tag:blogger.com,1999:blog-5309053798160013742024-03-13T17:13:04.396-07:00DWF متخصصون فى الHVAC و ال MEP للتكييف ومشروعات التكييف المركزى من تصميم واستشارات للمشروعات والفلل والمنازل وحسابات الاحمالmohammed saifhttp://www.blogger.com/profile/04808794259319186322noreply@blogger.comBlogger12125tag:blogger.com,1999:blog-530905379816001374.post-71883741749958616152019-01-29T00:10:00.001-08:002020-05-11T06:38:16.840-07:00تحميل احدث نسخه من برنامج ال HAP<div dir="rtl" style="text-align: right;" trbidi="on">
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<span style="color: red;"><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 18pt; line-height: 27.6px;">ما هو برنامج تحليل </span><span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; font-size: 18pt; line-height: 27.6px;">الاحمال HAP</span></span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 18pt; line-height: 27.6px;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 18pt; line-height: 27.6px;">يعد برنامج تحليل الاحمال الشائع</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 18pt; line-height: 27.6px;"><span dir="LTR"></span><span dir="LTR"></span> Carrier </span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 18pt; line-height: 27.6px;">اثنين من الأدوات الفعالة في حزمة واحدة. </span><span style="font-size: 18pt; line-height: 27.6px;">HAP </span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 18pt; line-height: 27.6px;">ميزات متنوعة لتصميم أنظمة</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 18pt; line-height: 27.6px;"><span dir="LTR"></span><span dir="LTR"></span> HVAC</span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 18pt; line-height: 27.6px;">لل</span><span dir="LTR"></span><span dir="LTR"></span><span lang="AR-SA" style="font-size: 18pt; line-height: 27.6px;"><span dir="LTR"></span><span dir="LTR"></span> </span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 18pt; line-height: 27.6px;">للمباني التجارية. كما يوفر إمكانات قوية لتحليل الطاقة لمقارنة استهلاك الطاقة وتكاليف التشغيل لبدائل التصميم. من خلال الجمع بين كل الأدوات في حزمة واحدة يتم تحقيق وفورات كبيرة في الوقت. يمكن استخدام بيانات المدخلات والنتائج من حسابات تصميم النظام مباشرة في دراسات الطاقة. والله </span><span style="font-size: 18pt; line-height: 27.6px;"><o:p></o:p></span><br />
<span dir="RTL" lang="AR-SA" style="font-family: arial, sans-serif; font-size: 35.078px; line-height: 27.6px;"><a href="https://fbs.ae/promo/trade-100usd?ppu=9201621" target="_blank" style="outline: none"><img src="https://fbs.ae/upload/promo/banner/699e4252e269a87d69629d2d04e657f1.gif?ppu=9201621" width="300" height="250" border="0"></a></span><br />
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<span style="color: red;"><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 18pt; line-height: 27.6px;">من يستطيع الاستفادة من</span><span dir="LTR"></span><span dir="LTR"></span><span lang="AR-SA" style="font-size: 18pt; line-height: 27.6px;"><span dir="LTR"></span><span dir="LTR"></span> <span style="mso-spacerun: yes;"> HAP</span></span></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 18pt; line-height: 27.6px;">تم تصميم</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 18pt; line-height: 27.6px;"><span dir="LTR"></span><span dir="LTR"></span> HAP </span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 18pt; line-height: 27.6px;">للاستشارات الهندسية ، ومقاولي التصميم / البناء ، ومتعهدي</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 18pt; line-height: 27.6px;"><span dir="LTR"></span><span dir="LTR"></span> HVAC </span><span dir="RTL"></span><span dir="RTL"></span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 18pt; line-height: 27.6px;"><span dir="RTL"></span><span dir="RTL"></span>، ومهندسي المرافق وغيرهم من المهنيين المشاركين في تصميم وتحليل أنظمة.</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 18pt; line-height: 27.6px;"><span dir="LTR"></span><span dir="LTR"></span> HVAC </span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 18pt; line-height: 27.6px;">لبناء المباني التجارية</span><span style="font-size: 18pt; line-height: 27.6px;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 18pt; line-height: 27.6px;">بالإضافة إلى ذلك ، فإن قدرات تحليل الطاقة التي تبلغ 8760 ساعة في</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 18pt; line-height: 27.6px;"><span dir="LTR"></span><span dir="LTR"></span> HAP </span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 18pt; line-height: 27.6px;">مفيدة جدًا لتصميم المباني الخضراء. على سبيل المثال ، يتم قبول نتائج تحليل الطاقة</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 18pt; line-height: 27.6px;"><span dir="LTR"></span><span dir="LTR"></span> HAP </span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 18pt; line-height: 27.6px;">ت المتحدة لنظام التقييم</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 18pt; line-height: 27.6px;"><span dir="LTR"></span><span dir="LTR"></span> (</span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 18pt; line-height: 27.6px;">القيادة في الطاقة والتصميم البيئي). </span></div>
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<span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 18pt; line-height: 27.6px;">تطبيقات مفيدة</span><span style="font-size: 18pt; line-height: 27.6px;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 18pt; line-height: 27.6px;">البرنامج هو أداة قوية لتصميم أنظمة ومكونات نظام التحجيم. يمكن لـ</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 18pt; line-height: 27.6px;"><span dir="LTR"></span><span dir="LTR"></span> HAP </span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 18pt; line-height: 27.6px;">بسهولة التعامل مع المشاريع التي تشمل</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 18pt; line-height: 27.6px;"><span dir="LTR"></span><span dir="LTR"></span>:<o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 18pt; line-height: 27.6px;">المباني التجارية الصغيرة إلى الكبيرة. الأنظمة بما في ذلك أسطح المنازل المعبأة ، معالجات الهواء المركزية المعبأة والمبنية ، وملفات المروحة ، و</span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 18pt; line-height: 27.6px;"> ذلك. أنواع كثيرة من وحدات التحكم في حجم ثابت و</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 18pt; line-height: 27.6px;"><span dir="LTR"></span><span dir="LTR"></span> VRV. </span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 18pt; line-height: 27.6px;">مباني المكاتب الصغيرة ، ومحلات البيع بالتجزئة ، ومراكز التسوق ، والمدارس ، والكنائس ، والمطاعم ، ومباني المكاتب الكبيرة ، والفنادق ومراكز التسوق والمستشفيات والمصانع والمباني متعددة الاستخدامات. تصميم جديد أو إعادة تأهيل أو صيانة الطاقة.</span><span style="font-size: 18pt; line-height: 27.6px;"><o:p></o:p></span></div>
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<span style="font-family: "arial" , sans-serif;"><span style="font-size: 24px;">لتحميل برنامج الHAP من موقع ahi-carrie</span></span></div>
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<span style="font-family: "arial" , sans-serif;"><span style="font-size: 24px;"><a href="http://festyy.com/wVM8h7" target="_blank"><span style="color: red;">اضغط الرابط التالى</span></a></span></span></div>
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<span style="font-family: "arial" , sans-serif; font-size: large;">ثم اذهب الى نهاية الصفحه لمزيد من المعلومات ارجوا المراسله او التعليق</span><br />
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mohammed saifhttp://www.blogger.com/profile/04808794259319186322noreply@blogger.com0tag:blogger.com,1999:blog-530905379816001374.post-13203433628256203152019-01-14T12:28:00.002-08:002020-05-02T03:36:41.333-07:00DWF<div dir="rtl" style="text-align: right;" trbidi="on">
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<span style="background-color: white; font-size: x-large;">لتصاميم MEP </span></div>
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<span style="background-color: white; font-size: x-large;">وتصميم انظمة التكييف المختلفه بالتعاون مع شركة</span></div>
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<span style="background-color: white; font-size: x-large;"> DWF</span></div>
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<span style="background-color: white; font-size: x-large;"> للتصاميم الهندسية </span></div>
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<span style="background-color: white; font-size: x-large;">متخصصون فى مجال تهوية وتكييف المنازل</span></div>
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<span style="font-size: x-large;"><a href="https://khamsat.com/designing/presentation/955434?r=754209" target="_blank">يرجى الضغط هنا والتواصل</a></span><br />
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<span style="font-family: "georgia" , "times new roman" , serif; font-size: x-large;"> <span style="color: orange;"> <span dir="RTL" lang="AR-SA">بناء أنظمة التكييف لل</span></span></span></h2>
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<span style="font-size: large;">Vrv system</span><br />
<span style="font-size: large;">Shiller</span><br />
<span style="font-size: large;">Multi spilt</span><br />
<span style="font-size: large;">Mini spilt</span><br />
<span style="font-size: large;">Package</span><br />
<span style="font-size: large;">Cast</span><br />
<span style="font-size: large;">Stand</span><br />
<span style="font-size: large;">Ahu</span></div>
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<span style="font-size: large;"> <span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">تدفئة</span><o:p></o:p></span></div>
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<span style="font-size: large;"> <span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">أنظمة التبريد</span><o:p></o:p></span></div>
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<span style="font-size: large;"> <span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">التهويه</span><o:p></o:p></span></div>
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<span style="font-size: large;"> HVAC <o:p></o:p></span></div>
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TO CONTACT US Please Sending to : muhammedsaif1993@gmail.com<br />
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<span style="color: purple; font-size: large;">مع تراكم خبرات فريقنا لاكثر من ست سنوات فى شمال افريقيا والشرق الاوسط</span><br />
<span style="color: purple; font-size: large;">مشروعك فى ايد امينه</span></div>
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mohammed saifhttp://www.blogger.com/profile/04808794259319186322noreply@blogger.com0tag:blogger.com,1999:blog-530905379816001374.post-17082096745792472392019-01-14T12:13:00.003-08:002019-01-16T11:33:18.453-08:00المراحل الاوليه لفحص وصيانة المكيفات<div dir="rtl" style="text-align: right;" trbidi="on">
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<span lang="AR-SA" style="font-size: 16.0pt; line-height: 115%;"> </span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">نعمل في مجال التدفئة والتبريد منذ أكثر
من 20 عام ، وفي كل صيف نتلقي مكالمات من أصحاب المنازل المجهزين متسائلين عما إذا
كانوا بحاجة إلى إصلاح مكيفات الهواء. فيما يلي الإجابات (ونصائح الإصلاح) لبعض هذه
الأسئلة الشائعة حول إصلاح مكيف الهواء</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></span></div>
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<span dir="RTL"></span><span dir="RTL"></span><span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><span dir="RTL"></span><span dir="RTL"></span>1.</span><span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">كيف يمكنني معرفة ما إذا كان
مكيف الهواء الخاص بي معطلًا؟</span><span style="color: red; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">إذا توقف الهواء البارد عن التدفق ، فإن
أول شيء يجب عليك فعله هو فحص منظم الحرارة</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">فيما يلي الخطوات التي يجب اتخاذها</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">إذا كانت شاشة الترموستات فارغة ، قم بتغيير
البطاريات</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">إذا كانت الشاشة فارغة ، فقم بإزالة منظم
الحرارة من الحائط وتحقق من الأسلاك للتأكد من أنها تحصل على الطاقة. استخدم مقياس
متعدد للتحقق من الفولتية</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">إذا كنت لا تحصل على جهد كهربائي ، فتحقق
من مربع المصاهر لمعرفة ما إذا كانت هناك أية صمامات تم نفخها أو تعثرها. إذا كانت
الصمامات تبدو جيدة ، فقم بتحديد موقع المفتاح المتصل بالتكييف المركزي الخاص بك وقم
بتشغيله وإيقافه لإعادة ضبط الاتصال</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">إذا كانت تحصل على الطاقة ، ولكن لا تزال
الشاشة فارغة ، فاخرج إلى الخارج وتحقق من المكثف لمعرفة ما إذا كان قد تم تعتيم الفتيل</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">إذا كان منظم الحرارة لديك لا يعمل ، فقد
يكون الوقت قد حان لاستبداله. تحقق من الضمان لمعرفة ما إذا انتهت صلاحيته</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">إذا كان منظم الحرارة يعمل ، ولكن مكيف
الهواء لن يعمل ، فيجب عليك أيضًا</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">قم بتشغيل المروحة لمعرفة ما إذا كان المنفاخ
يحصل على الطاقة</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">غيّر فلتر الهواء إذا كان عمره أكثر من
شهر واحد. تراكم الأوساخ والحطام يمكن منع تدفق الهواء</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">تحقق من استنزاف التكثيف</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">إذا كنت لا تزال تواجه مشكلات ، فاتصل بمهني</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span> HVAC<o:p></o:p></span></div>
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<span dir="RTL"></span><span dir="RTL"></span><span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><span dir="RTL"></span><span dir="RTL"></span>2.</span><span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">متى يجب علي استبدال مكيف الهواء
الخاص بي؟</span><span style="color: red; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">استبدال مكيف الهواء الخاص بك هو استثمار</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">وهنا بعض الأشياء في الاعتبار:</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>:<o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">عمر مكيف الهواء الخاص بك. عمر مكيف الهواء
في مكان ما بين 10 و 20 سنة. لذلك ، إذا كان مكيف الهواء الخاص بك أكثر من 10 سنوات
، فقد يكون الوقت قد حان لاستبداله</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">ارتفاع فواتير الطاقة. كلما كبرت مكيفات
الهواء ، أصبحت أقل كفاءة في استخدام الطاقة. لمعرفة ما إذا كان مكيف الهواء الخاص
بك يفقد الكفاءة ، قارن بين فواتير الخدمات الخاصة بك على مدار الصيف الماضي. إذا كانت
تكاليفك ترتفع ، فقد تكون علامة على أن مكيف الهواء الخاص بك يتردى</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">تسرب المبردات. إن ﻏﺎزات اﻟﺘﺒﺮﻳﺪ ﻟﻴﺴﺖ ﻣﻜﻠﻔﺔ
ﻓﻘﻂ ، ﺑﻞ أن ﺗﺴﺮب ﻏﺎزات اﻟﺘﺒﺮﻳﺪ ﺳﻮف ﻳﺆدي إﻟﻰ اﻧﺨﻔﺎض اﻟﻤﻜﺒﺮ. قد يسبب نوع المبرد الذي
يحتاجه مكيف الهواء الخاص بك أيضًا مشكلات في الطريق</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">تكلفة الاصلاح. اتصل بشركة</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span> HVAC </span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">المحلية للحصول على عرض مجاني لتكاليف الإصلاح.
إذا كان أكثر من 3000 دولار ، فقد يكون من الأرخص شراء وحدة جديدة</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></span></div>
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<span style="color: red;"><span dir="RTL"></span><span dir="RTL"></span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><span dir="RTL"></span><span dir="RTL"></span>3.</span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">لماذا يتجمد مكيف الهواء الخاص بي؟</span></span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">تحدث جميع حالات تجميد أجهزة تكييف الهواء
تقريبًا بسبب نقص في مادة التبريد ، أو نقص تدفق الهواء إلى ملفات المبخر. إذا تم تجميد
مكيف الهواء الخاص بك ، فإن أول شيء يجب عليك فعله هو إيقاف تشغيله. إذا استمر تشغيله
، فقد يتلف الضاغط</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="color: #c00000; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">تحقق من العناصر التالية</span><span style="color: red; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">ترموستات درجة الحرارة الإعداد. إذا تم
ضبط الترموستات الخاص بك إلى أقل من 70 درجة ، فقد يؤدي ذلك إلى تجمد مكيف الهواء الخاص
بك - وهو في الواقع لا يبرد منزلك بشكل أسرع</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">مستوى التبريد. إذا كان مستوى سائل التبريد
لديك منخفضًا ، فقد يشير ذلك إلى مشكلة أكبر ، وننصح بالاتصال بالمحترف لإلقاء نظرة</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">مرشح الهواء. قد يكون فلتر الهواء الملوث
المسدود هو سبب المشكلة. كما ذكر أعلاه ، غيّر الفلتر إذا مر أكثر من شهر على آخر تغييرالمنافس.<o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><span style="mso-spacerun: yes;"> </span>تأكد من فتح جميع فتحات التهوية لضمان تدفق الهواء
إلى ملف المبخر</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">لفائف المبخر. إذا تم حظر ملفات المبخر
بواسطة الأوساخ والحطام ، فقد يكون هذا سبب المشكلة</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">معجب. مروحة الخاص بك هو ما ينفخ الهواء
البارد من خلال مجاري الهواء في منزلك - ويساعد أيضا على إعادة الهواء إلى ملف المبخر</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">اقرأ "لماذا يتم تجميد مكيف الهواء
الخاص بي؟" لمزيد من التفاصيل</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></span></div>
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<span dir="RTL"></span><span dir="RTL"></span><span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><span dir="RTL"></span><span dir="RTL"></span>4.</span><span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">لماذا يتسرب جهاز تكييف الهواء
الخاص بي؟ يجب أن أكون قلقا؟</span><span style="color: red; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">وظيفة واحدة لمكيفات الهواء هي لاستخراج
الرطوبة من الهواء ، لذلك القليل من التكثيف أمر طبيعي. ومع ذلك ، تشير التسريبات عادةً
إلى وجود مشكلة في طريقة استنزاف المكثفات</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">الأمور التالية يمكن أن تسبب هذه المشكلة</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">خط تكثيف مسدود</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">وعاء مكثف صدئ</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">ملف مبخر قذر أو مجمد</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">مستوى منخفض من المبردات</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">فلتر هواء قذر</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">مشكلات التثبيت</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">للحصول على نصائح حول كيفية التحقيق في
كل منها ، راجع مقالتنا "مكيف الهواء الخاص بي يتسبب في تكاثف التكثيف".
ماذا الآن؟</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>"<o:p></o:p></span></div>
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<br /></div>
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<span dir="RTL"></span><span dir="RTL"></span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><span dir="RTL"></span><span dir="RTL"></span>5.</span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">كيف أغير فلتر الهواء؟</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">كما ذكر أعلاه ، يجب عليك تغيير فلتر الهواء
الخاص بك بانتظام لضمان تشغيل مكيف الهواء بكفاءة - وعدم المساهمة في مشاكل الصيانة
الأخرى</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">لتغيير الفلتر ، اتبع</span><span style="font-size: 16.0pt; line-height: 115%; mso-bidi-font-family: Arial;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">اختر الحجم المناسب. أزل الفلتر القديم
وقاسه أو اقرأ دليل المستخدم</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">اختر</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span> MERV. </span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">تشير</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>
MERV </span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">إلى
"الحد الأدنى لقيمة الإبلاغ عن الكفاءة" وتتراوح من 1-20. كلما زاد</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span> MERV </span><span dir="RTL"></span><span dir="RTL"></span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><span dir="RTL"></span><span dir="RTL"></span>، كلما كان فلتر الهواء أكثر فاعلية</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">اختر نوع الفلتر. يمكنك الاختيار من الألياف
الزجاجية ، قابل للغسل ، أو المرافعة أو الإلكترونية</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">تثبيته. معظم مرشحات الهواء سهلة التركيب
للغاية. اتبع تعليمات الشركة المصنعة</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">احصل على مزيد من التفاصيل حول هذا الموضوع
، حيث يمكنك قراءة "كيف تقوم بتغيير فلتر تكييف الهواء الخاص بك</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>"<o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">إذا كان لديك سؤال آخر حول إصلاح تكييف
الهواء <a href="https://khamsat.com/designing/presentation/955434-%D8%AD%D8%B3%D8%A7%D8%A8-%D8%A7%D8%AD%D9%85%D8%A7%D9%84-%D9%88%D8%AA%D8%B5%D9%85%D9%8A%D9%85-%D8%AE%D8%B1%D8%B7-%D8%A7%D9%84%D8%AA%D9%83%D9%8A%D9%8A%D9%81-%D8%A7%D9%84%D9%85%D8%B1%D9%83%D8%B2%D9%89-16-%D9%85%D8%AA%D8%B1-%D9%85%D8%B1%D8%A8%D8%B9-%D8%A8%D9%89-5" target="_blank">للتواصل او طلب خدمه اضغط هنا</a></span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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mohammed saifhttp://www.blogger.com/profile/04808794259319186322noreply@blogger.com0tag:blogger.com,1999:blog-530905379816001374.post-6674427805247746322019-01-14T11:44:00.001-08:002019-01-14T13:52:00.240-08:00اسئله لمعاينات التبريد والتكييف<div dir="rtl" style="text-align: right;" trbidi="on">
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgfAEf9CO7GV38NewFLH8C-R5WDPpAR9yAZG6u3sjdhF68e0uPKmSv2IKidRtpblY4iEfooo-bylteTfNPBUf1Oe4U_mylvTWsu-dBHLw1SsXqDsZBEfQpAcRVTtkrH3NfHbIC6wuba18KC/s1600/Slide1.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="720" data-original-width="960" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgfAEf9CO7GV38NewFLH8C-R5WDPpAR9yAZG6u3sjdhF68e0uPKmSv2IKidRtpblY4iEfooo-bylteTfNPBUf1Oe4U_mylvTWsu-dBHLw1SsXqDsZBEfQpAcRVTtkrH3NfHbIC6wuba18KC/s400/Slide1.JPG" width="400" /></a></div>
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<span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">السؤال 1. ما هي الرطوبة النسبية
عند نقطة التشبع؟</span><span style="color: red; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">الاجابة :</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">الرطوبة النسبية = 100٪</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">السؤال 2. شرح مبدأ التبريد؟</span><span style="color: red; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">الاجابة :</span><span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">العملية وفقا للقانون الثاني للديناميكا
الحرارية - الحرارة يمكن أن تتدفق من الجسم البارد إلى الجسم الساخن بمساعدة مصدر خارجي</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">السؤال 3. ما هو مكيفات الهواء؟</span><span style="color: red; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">الاجابة :</span><span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">يقوم مكيف الهواء بسحب الهواء من الفضاء
المراد تبريده وتبريده بمبدأ التبريد وتفريغه مرة أخرى إلى نفس المساحة الداخلية التي
تحتاج إلى تبريد</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span style="color: red; font-size: 16.0pt; line-height: 115%;">Wet Bulb Depression</span><span dir="RTL"></span><span dir="RTL"></span><span dir="RTL" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><span dir="RTL"></span><span dir="RTL"></span> </span><span dir="RTL" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><span style="mso-spacerun: yes;"> </span><span style="mso-spacerun: yes;"> </span><span lang="AR-SA">السؤال 4. ما هو<span style="mso-spacerun: yes;"> </span></span></span><span style="color: red; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">الاجابة :</span><span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">إن هو الفرق بين درجة حرارة الثيرموميتر
الجاف ودرجة حرارة الثيرموميتر المبلل</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">السؤال 5. تعريف الرطوبة النسبية؟</span><span style="color: red; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">الاجابة :</span><span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">الرطوبة النسبية هي النسبة بين محتوى الرطوبة
الفعلي للهواء مقارنة مع محتوى الرطوبة في الهواء المطلوب للتشبع في نفس درجة الحرارة</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">السؤال 6. ما هو التبريد؟</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">الاجابة :</span><span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">التبريد هو عملية التبريد المستمر أو استخراج
الحرارة من الغلاف الجوي أو البيئة المحيطة بمساعدة العمل الخارجي</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">السؤال 7. الفرق بين التبريد
ومضخة الحرارة؟</span><span style="color: red; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">الاجابة :</span><span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">تقوم الثلاجات بإخراج الحرارة لكن مضخات
الحرارة تعطي الحرارة </span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">تحتوي الثلاجة على المضخة الحرارية ، وتضخ
الحرارة بحيث يبقى نظامك باردًا</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">السؤال 8. ما هي نسبة الحرارة
معقولة<o:p></o:p></span></div>
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<span dir="LTR"></span><span dir="LTR"></span><span lang="AR-SA" style="color: red; font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span><span style="mso-spacerun: yes;"> </span></span><span style="color: red; font-size: 16.0pt; line-height: 115%;">(shr)</span><span dir="RTL"></span><span dir="RTL"></span><span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><span dir="RTL"></span><span dir="RTL"></span>؟</span><span style="color: red; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">الاجابة :</span><span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">نسبة الحرارة الحساسة</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span> (SHR) </span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">تعبر عن النسبة بين الحمل الحراري المعقول
والحمل الحراري الكلي</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span style="color: red; font-size: 16.0pt; line-height: 115%;">.9</span><span dir="RTL"></span><span dir="RTL"></span><span dir="RTL" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><span dir="RTL"></span><span dir="RTL"></span> <span lang="AR-SA">السؤال</span></span><span style="color: red; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">لماذا معدل التكثيف أعلى على
سطح مصقول بالمقارنة مع السطح الصدئ</span><span style="color: red; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">الاجابة :</span><span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">سطح مصقول يعزز انخفاض التكثيف ولا يبلل
السطح</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">السؤال 10. ما هو التبريد الميكانيكي؟</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<br /></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">إجابة</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span> :<o:p></o:p></span></div>
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<br /></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">تبريد من قبل جهاز ما</span><span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<br /></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">السؤال 11. تصنيف أنظمة التبريد
المختلفة؟</span><span style="color: red; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<br /></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">الاجابة :</span><span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<br /></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">قد يكون من الأنواع الثلاثة التالية</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>:<o:p></o:p></span></div>
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<br /></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">نظام التبريد بضغط البخار</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">نظام التبريد امتصاص البخار</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">أنظمة تبريد الهواء</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<br /></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">السؤال 12.ما هي الوحدات الأساسية
لنظم التبريد الميكانيكية؟</span><span style="color: red; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<br /></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">الاجابة :</span><span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<br /></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">نظام التبريد يحتوي على 4 وحدات أساسية</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<br /></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">مبخر - وحدة التبريد</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">مضخة أو ضاغط</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">المكثف - المتخلص للحرارة</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">جهاز خلط سائل - صمام توسيع أو أسطوانة
أو أنبوب شعري<o:p></o:p></span></div>
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<br /></div>
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<span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">السؤال 13. أي وحدة تنتج تأثير
التبريد في نظام التبريد؟</span><span style="color: red; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<br /></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">الاجابة :</span><span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<br /></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">المبخر</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<br /></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">السؤال 14. ما هي وحدة التبريد؟</span><span style="color: red; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<br /></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">الاجابة :</span><span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<br /></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">بما أن وحدة الطاقة للأجهزة الميكانيكية
مقدمة من</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>
H.P </span><span dir="RTL"></span><span dir="RTL"></span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><span dir="RTL"></span><span dir="RTL"></span>،
فبالنسبة للمعدات الكهربائية ، تكون وحدة الطاقة</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span> kW </span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">أو</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>
MW. </span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">بنفس
الطريقة فإن وحدة التبريد هي "طن من التبريد</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>"<span style="color: red;"><o:p></o:p></span></span></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">السؤال 15. ما هو واحد طن من
التبريد؟</span><span style="color: red; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<br /></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">الاجابة :</span><span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<br /></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">واحد طن من التبريد يعني أن الآلة قادرة
على إزالة الحرارة من جسم مساو للحرارة الممتصة بمقدار طن واحد من الثلج عندما يذوب
من 0 درجة مئوية إلى صفر درجة مئوية من الماء خلال 24 ساعة. هنا طن واحد يساوي
2000 رطل</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></span></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<br /></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">السؤال 16. ما هي قدرة آلة طن
واحدة في نظام</span><span dir="LTR"></span><span dir="LTR"></span><span lang="AR-SA" style="color: red; font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span> </span><span style="color: red; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<span style="color: red; font-size: 16.0pt; line-height: 115%;"><span style="mso-spacerun: yes;"> </span>MKS</span><span dir="RTL"></span><span dir="RTL"></span><span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><span dir="RTL"></span><span dir="RTL"></span>؟</span><span style="color: red; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<br /></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">الاجابة :</span><span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<br /></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">في نظام</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span> MKS </span><span dir="RTL"></span><span dir="RTL"></span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><span dir="RTL"></span><span dir="RTL"></span>،
من المعروف أن الآلة التي لديها القدرة على إنتاج تأثير تبريد 50 كيلو كالوري / دقيقة
هي "آلة تون تون</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>"<o:p></o:p></span></div>
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<br /></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">السؤال 17. تعريف المشاركة الفعالة
للأداء؟</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
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<br /></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">الاجابة :</span><span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<br /></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">في حالة المحرك ، يتم الحكم على كفاءة المحرك.
هذا هو - الكفاءة = العمل المنجز / الحرارة الموردة</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></span></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<br /></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">وفي حالة التبريد ، يتم عكس العملية أولاً
، حيث يتعين علينا توفير العمل للحصول على درجة حرارة أقل أو القول عن إزالة الحرارة.
وبالتالي يتم عكس أداء التبريد فقط. هذا هو</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span> - N / W<o:p></o:p></span></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<br /></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">حيث</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span> - N = </span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">معدل الحرارة المستخرجة من الجسم في وقت معين يسمى تقنيًا "تأثير
التبريد الصافي" و</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>
W = </span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">العمل
المنجز</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></span></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<br /></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">وهكذا</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span> COP = </span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">صافي تأثير التبريد / العمل المقدمة. هذا يسمى</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span> COP </span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">النظرية</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></span></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<br /></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">السؤال 18. ما هو شرطي النسبي؟</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<br /></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">الاجابة :</span><span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<br /></div>
<div align="right" class="MsoNormal" style="text-align: right;">
<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">هو نسبة</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span> COP </span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">الفعلي و</span><span dir="LTR"></span><span dir="LTR"></span><span style="font-size: 16.0pt; line-height: 115%;"><span dir="LTR"></span><span dir="LTR"></span>
COP </span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 16.0pt; line-height: 115%;">النظري</span><span style="font-size: 16.0pt; line-height: 115%;"><o:p></o:p></span></div>
<br /></div>
mohammed saifhttp://www.blogger.com/profile/04808794259319186322noreply@blogger.com0tag:blogger.com,1999:blog-530905379816001374.post-30492358513952857422018-12-18T06:36:00.000-08:002019-01-16T11:02:32.378-08:00فحص جهاز التحكم عن بعد<div dir="rtl" style="text-align: right;" trbidi="on">
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjYy0XnQ3B-7UNRNqyQQ4iXHt0-4uBpoHDl0lAb9TNFBjM21GktPR71_ypnPF6YM3TzfdEuybgfc7DtNaMmms5H5t9DTOcrnYlWQXxunXK1qwzhl-nDXjr79CMJlrmiC33p70xbgUYF-ZDS/s1600/item_XL_5103816_1840220.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="477" data-original-width="600" height="317" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjYy0XnQ3B-7UNRNqyQQ4iXHt0-4uBpoHDl0lAb9TNFBjM21GktPR71_ypnPF6YM3TzfdEuybgfc7DtNaMmms5H5t9DTOcrnYlWQXxunXK1qwzhl-nDXjr79CMJlrmiC33p70xbgUYF-ZDS/s400/item_XL_5103816_1840220.jpg" width="400" /></a></div>
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<span style="color: red;">كيفية التحقق من جهاز التحكم عن بعد؟</span><br />
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فحص جهاز التحكم عن بعد<br />
أخذت أجهزة التحكم عن بعد بالأشعة تحت الحمراء مكانها بقوة في مجال الإلكترونيات الاستهلاكية. ما هو نوع المعدات التي لا تكملها مع هذا الجهاز المريح للغاية ، فهي أجهزة التلفزيون ، وأجهزة الإستريو ، وأفران الميكروويف ، ومشغلات CD / MP للسيارة ، والثريات والعديد من الأشياء الأخرى التي اعتدنا عليها.<br />
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مثل هذا التوزيع الواسع لأجهزة التحكم عن بعد لا يمكن أن يؤثر على الأعطال المتكررة. نظرًا لأنه من الصعب أحيانًا الحصول على جهاز جديد ضروري للتحكم عن بعد بجهاز معين ، يتم تسليمه للإصلاح.<br />
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<span style="color: #e69138;">كيف تحقق بسرعة من جهاز التحكم عن بعد؟</span><br />
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يمكن اعتبار أبسط الطرق وأكثرها فعالية في فحص أجهزة التحكم عن بعد (RC) بمساعدة الكاميرات الرقمية. الآن تقريبا كل هاتف خلوي لديه كاميرا رقمية.<br />
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العديد من أجهزة الكمبيوتر المحمولة لديها كاميرا ويب مدمجة. بالنسبة إلى أجهزة الكمبيوتر المحمولة ، تعد كاميرا الويب الرقمية سمة مطلوبة بشكل عام. أيضا ، الكاميرات الرقمية وكاميرات الفيديو هي مناسبة لفحص أجهزة التحكم عن بعد. بشكل عام ، فإن أي جهاز يوجد فيه أبسط كاميرا رقمية سوف يتناسب مع جهاز التحكم عن بعد.<br />
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لفحص جهاز التحكم عن بعد ، من الضروري فقط توجيه ضوء الأشعة تحت الحمراء المتجه إلى عدسات الكاميرا. على الشاشة الرقمية ، سيؤدي الضغط على الأزرار الموجودة على جهاز التحكم عن بعد إلى عرض ومضات دورية من الضوء الملون البنفسجي. هذا يدل على صحة جهاز التحكم عن بعد.<br />
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تعرض الصورة لمبة LED بالأشعة تحت الحمراء التي يتم التقاطها بواسطة كاميرا الهاتف المحمول Sony Ericsson K810i.<br />
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الصمام بالأشعة تحت الحمراء ومضات<br />
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إذا لم تكن هناك أجهزة مزودة بكاميرا رقمية ، فيمكنك استخدام الطريقة التالية.<br />
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فمن الضروري بدلا من الصمام الأشعة تحت الحمراء لحام مؤقت الصمام الثنائي التقليدي الذي ينبعث منها الضوء. يمكن أن يكون الصمام أي لون من الضوء: أحمر ، أخضر ، أصفر ، أبيض ، بشكل عام ، لا يهم ، الشيء الرئيسي هو أن الصمام هو 3 فولت.<br />
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عند الضغط على أزرار جهاز التحكم عن بعد ، سيصدر مؤشر LED العادي الملحوم مؤقتًا ومضات من الضوء. تجدر الإشارة إلى أن سطوع الإشعاع سيكون صغيرًا.<br />
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في الصورة - LED الأبيض المعتاد ، ملحوم بدلا من الأشعة تحت الحمراء.<br />
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فحص التحكم عن بعد<br />
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يمكن<span style="color: #e69138;"> التحقق من جهاز التحكم عن بعد باستخدام الثنائيات الضوئية تحت الحمراء ومنظار الذبذبات.</span><br />
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في هذه الحالة ، يتم توصيل الضوئي الضوئي بالأشعة تحت الحمراء بمدخل الذبذبات. عند تشغيل جهاز التحكم عن بعد ، سيعرض جهاز الذبذبات نبضات قصيرة من النبضات. من المهم أن يتم توصيل الثنائي الضوئي بالمدخل المفتوح لمنبس الذبذبات.<br />
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ببساطة وبسهولة يمكنك التحقق من أداء أي جهاز تحكم عن بعد بالأشعة تحت الحمراء. للقيام بذلك ، ليس من الضروري على الإطلاق تجميع أي من دارات أخذ العينات وفوضى في ورشة العمل المثقلة بالأعباء ، لأن جميع الأدوات الضرورية متوفرة بالفعل ، لذا فإن الهاتف المحمول المزود بالكاميرا</div>
mohammed saifhttp://www.blogger.com/profile/04808794259319186322noreply@blogger.com0tag:blogger.com,1999:blog-530905379816001374.post-55762840442678345792018-12-18T06:22:00.000-08:002019-01-14T13:59:01.093-08:00 عدم عمل ريموت كنترول المكيف<div dir="rtl" style="text-align: right;" trbidi="on">
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<span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">لماذا لا يتم تشغيل مكيف الهواء؟</span></span><br />
<span style="background-color: #990000; font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">بغض النظر عن العلامة التجارية ونوع مكيف الهواء ، فإن أسباب عدم تشغيله هي نفسها.</span><br />
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<span style="background-color: #990000; font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;"><br /></span></div>
<span style="background-color: #990000;"><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;"><span style="color: #e06666;">الأسباب الرئيسية:</span></span></span><br />
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<span style="font-family: "roboto" , "arial" , sans-serif;"><span style="background-color: #990000; font-size: 18px; white-space: pre-wrap;">الكترونيك</span></span></div>
<span style="background-color: #990000; font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">باور او عدم وجود كهرباء</span><br />
<span style="background-color: #990000; font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">لوحة تحكم خاطئة</span><br />
<span style="background-color: #990000; font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">ربط الربط</span><br />
<span style="background-color: #990000; font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">لوحة تحكم خاطئة أو وحدة استقبال في مكيف الهواء</span><br />
<span style="background-color: #990000; font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">محمي مكيف الهواء ، ويعطي خطأ</span><br />
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<span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">تشخيص الخطأ</span></span><br />
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<span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">نقص القوة</span></span><br />
<span style="background-color: #990000;"><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">من الضروري أن نفهم كيف يتم تضمين مكيف الهواء في الشبكة - مع قابس أو أوتوماتيكي:</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">إذا تم توصيل قابس الطاقة ، فأنت بحاجة إلى التحقق مما إذا كان قيد التشغيل.</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">إذا كان تشغيله ، فإن الخطوة التالية هي التحقق من وجود الطاقة في المقبس نفسه - مع مفك مفك أو مؤشر متعدد.</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">إذا كانت هناك قوة في المخرج ، فإننا نتحقق من وجود التيار الكهربائي مباشرة في مكيف الهواء نفسه - في محطات الوحدة الداخلية أو الخارجية (يعتمد على طريقة توصيل جهاز تكييف الهواء)</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">إذا لم يكن هناك جهد ، فإن كبل الطاقة مكسور - نقوم بتغييره ،</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">إذا كان هناك - مشكلة في المجلس الداخلي لأجهزة تكييف الهواء.</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;"> </span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">أيضا ، يمكن لمكيف الهواء الحصول على الطاقة من صندوق التوزيع الكهربائي من خلال قاطع الدائرة.</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">نحن نبحث عن جهاز مغلقاً ونشغله ،</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">إذا لم يكن الأمر كذلك ، فبالنسبة للنقوش الموجودة على لوحة القيادة ، نبحث عن نوع الجهاز الأوتوماتيكي الذي يغذي مكيف الهواء.</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">قياس الجهد عند المدخلات والمخرجات.</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">إذا كان هناك مدخلاً ، ولا يوجد مخرج - فالأوتوماتي يكون معيبًا ، إذا كان هناك واحد أيضًا ، فهناك انهيار لكبل الإمداد في مكان ما.</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">الخلاصة: لإصلاح مكيف الهواء في هذه الحالة ، تحتاج إلى أدوات تركيب بسيطة - المفكات ، قواطع الأسلاك ، فضلا عن مفك البراغي مؤشر أو ، أفضل بكثير ، الفولتميتر.</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">تحذير! إذا لم يكن لديك التدريب المناسب. لا تنفذ هذه الإجراءات!</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;"> </span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;"><span style="color: #ea9999;">عطل لوحة التحكم</span></span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;"> </span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">لوحات المفاتيح هي الجدار ، السلكية واللاسلكية ، عن بعد.</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">التحكم عن بعد لاسلكية التحكم في مكيف الهواء باستخدام الأشعة تحت الحمراء (IR) ، باستخدام هذه الخاصية ، يمكنك بسهولة التحقق من حالة جهاز التحكم عن بعد مع كاميرا الهاتف العادية أو أي دولة أخرى ، لمزيد من التفاصيل ، راجع هذه المقالة.</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">إذا كان يعمل عن بعد ، ولكن مكيف الهواء لا يزال لا يعمل ، فإن رسوم الاستقبال به خاطئة.</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;"> </span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">من السهل التحقق من وحدة التحكم في الحائط - فهي تحتوي دائمًا على شاشة LCD ، وإذا لم تعمل ، فيجب إزالتها أولاً وقبل أن يتم التحقق من الفولتية في المحطات.</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">إذا كان كذلك ، يكون جهاز التحكم عن بعد معيبًا ، لذا يلزم استبداله أو إصلاحه.</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">في حالة عدم وجود جهد ، يجب البحث عن السبب في الأسلاك أو لوحة الدائرة للوحدة الداخلية لنظام الانقسام.</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;"> </span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">تكييف الهواء في الحماية عن طريق الخطأ</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;"> </span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">تحتوي كل أجهزة تكييف الهواء على نظام تشخيص ذاتي ، وبعضها يحتوي على نظام بسيط ، والبعض الآخر يحتوي على نظام أكثر ذكاء ، ولن يسمح لأجهزة تكييف الهواء بالفشل.</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">كيف تعرف ما هو الشرط في الخطأ؟</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">في هذه الحالة ، عادةً ما تومض المؤشرات على لوحة الوحدة الداخلية ،</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">عند التضمين من اللوحة ، يتم توزيع الإشارة الصوتية أو تغيرات الوميض</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">جهاز تكييف الهواء لا يزال لا يعمل أو يتحول ، ولكن بعد فترة من الوقت ينطفئ مرة أخرى.</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">إذا كانت وحدة التحكم مثبتة على الحائط ، فعادةً ما يتم عرض رمز الخطأ عليها ، على سبيل المثال؟ هي كما يلي:</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">E2 ، A5</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">00-00</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">خطأ 02</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;"> </span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;"> </span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">فك رموز الشفرات موجود في دليل الخدمة لمكيف الهواء أو على موقع ويب متخصص ، على سبيل المثال ، هنا.</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">قد يكون السبب هو:</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">تشغيل أجهزة استشعار الضغط في دائرة التبريد</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">ارتفاع درجة حرارة الضاغط</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">الاستهلاك الزائد الحالي ، وما إلى ذلك</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;"> </span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">لا يتم تشغيل تكييف الهواء في فصل الشتاء</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;"> </span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">هذه ظاهرة متكررة إلى حد ما بالنسبة لنماذج جديدة من أنظمة الانقسام ، وهذا ليس خطأ ، ولكن نظام حماية.</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">يتم تركيب مستشعر درجة حرارة الهواء على الوحدة الخارجية لمكيف الهواء ، وإذا كان الهواء شديد البرودة ، فإن مكيف الهواء لا يعمل ببساطة ، وهي القيمة الأكثر شيوعًا لدرجة حرارة التشغيل المنخفضة:</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">- 6 غرام مئوية</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">إذا كان من الضروري أن يعمل مكيف الهواء في درجات حرارة منخفضة ، فيجب معالجة هذه المشكلة في مرحلة الشراء والاختيار لمكيف الهواء ، ولكن كقاعدة ، تكون مثل هذه النماذج أكثر تكلفة.</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;"> </span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">عطل لوحة التحكم </span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;"> </span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">هذه هي مساحة كبيرة إلى حد ما من عطل ، أبسط شيء يمكن أن يحدث هو احتراق الصمامات ، الثرمستور.</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">أكثر من 90٪ من أسياد الثلاجات لا يقومون بتصليح الألواح الإلكترونية ، بل يقومون ببساطة بتغييرها إلى لوحات جديدة ، وهي مكلفة للغاية.</span><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><br style="font-family: roboto, arial, sans-serif; font-size: 18px; white-space: pre-wrap;" /><span style="font-family: "roboto" , "arial" , sans-serif; font-size: 18px; white-space: pre-wrap;">إذا كنت مهتمًا بموضوع إصلاح اللوحات الذاتية ، فقم بقراءة قسم "الإصلاح الذاتي لمكيفات الهواء" ، بالإضافة إلى الكتابة على "ثلاجات المنتدى".</span></span></div>
mohammed saifhttp://www.blogger.com/profile/04808794259319186322noreply@blogger.com0tag:blogger.com,1999:blog-530905379816001374.post-74191340880954209212018-12-18T05:41:00.001-08:002018-12-18T05:41:25.163-08:00مكونات المكيف الاسبيلت<div dir="rtl" style="text-align: right;" trbidi="on">
<span style="color: red; font-size: x-large;">تصميم وهيكل مكيف الاسبيلت</span><br />
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يعتبر مكيف الاسبيلت مثالًا لنوع جدار الفصل. تتكون الأنظمة المقسمة مع أنواع أخرى من الوحدات الداخلية من نفس العقد ، وتختلف فقط في المظهر.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9g4jAlRWp5RqLLl9B9DW8QDk8XXTwJvwwxEYGoq5cI5lEWiCx_e951QyGjZg4RbrSZ8TOr7bnQPrrgufjCArlQ4xVQ0yuHdRpTay8L51Imy_xUuMpc1MpKc6tOEg8g1G9hHLlq5Uq6mHy/s1600/ls091hsv3_99f17.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1600" data-original-width="1522" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9g4jAlRWp5RqLLl9B9DW8QDk8XXTwJvwwxEYGoq5cI5lEWiCx_e951QyGjZg4RbrSZ8TOr7bnQPrrgufjCArlQ4xVQ0yuHdRpTay8L51Imy_xUuMpc1MpKc6tOEg8g1G9hHLlq5Uq6mHy/s400/ls091hsv3_99f17.jpg" width="380" /></a></div>
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يعتبر مكيف الاسبيلت مثالًا لنوع جدار الفصل. تتكون الأنظمة المقسمة مع أنواع أخرى من الوحدات الداخلية من نفس العقد ، وتختلف فقط في المظهر.<br />
<span style="color: orange; font-size: large;">مكونات الوحده الخارجية :</span><br />
<span style="color: #cc0000; font-size: large;"> ضاغط</span> - يضغط الفريون ويدعم حركته على طول دائرة التبريد. ضاغط هو من المكبس أو نوع التمرير. تكون الضواغط الترددية أرخص ، ولكنها أقل موثوقية من ضواغط التمرير ، خاصة في درجات الحرارة المحيطة المنخفضة.<br />
<span style="color: #cc0000; font-size: large;">صمام رباعي الاتجاه</span> - مثبت في مكيفات الهواء القابلة للانعكاس (حرارة - باردة). في وضع التسخين ، يغير هذا الصمام اتجاه حركة الفريون. في الوقت نفسه ، يبدو أن الوحدات الداخلية والخارجية تغير الأماكن: تعمل الوحدة الداخلية للتدفئة ، والأخرى في الهواء الطلق للتبريد.<br />
<span style="font-size: large;"><span style="color: #cc0000;">يتم تثبيت لوحة التحكم</span> </span>- كقاعدة عامة فقط على مكيفات الهواء العاكسة. في الموديلات غير العاكسة ، تتم تجربة جميع الأجهزة الإلكترونية في الوحدة الداخلية ، نظرًا لأن الاختلافات الكبيرة في درجة الحرارة والرطوبة تقلل من موثوقية المكونات الإلكترونية.<br />
<span style="color: #cc0000; font-size: large;">مروحة</span> - يخلق تيار من الهواء الذي ينفخ مكثف. في النماذج منخفضة التكلفة لديها سرعة دوران واحدة فقط. يمكن لمكيف الهواء هذا العمل بثبات في مجموعة صغيرة من درجات الحرارة الخارجية. في الموديلات الراقية المصممة لمجموعة واسعة من درجات الحرارة ، وكذلك في جميع مكيفات الهواء التجارية ، تحتوي المروحة على 2 إلى 3 سرعات دوران ثابتة أو ضبط سلس.<br />
<span style="color: #cc0000; font-size: large;">المكثف</span> - المبرد ، الذي تبريد وتكثيف الفريون. يسخن الهواء من خلال المكثف وفقا لذلك.<br />
يتم تثبيت<span style="font-size: large;"> <span style="color: #cc0000;">مرشح نظام الفريون</span></span> - أمام مدخل الضاغط ويحميها من رقائق النحاس والجسيمات الصغيرة الأخرى التي قد تدخل إلى النظام أثناء تركيب مكيف الهواء. وبطبيعة الحال ، إذا تم تنفيذ التثبيت في انتهاك للتكنولوجيا ودخل كمية كبيرة من الحطام في النظام ، فلن يساعد الفلتر.<br />
<span style="color: #cc0000; font-size: large;">تركيبات</span> - يتم توصيل أنابيب النحاس لهم يربط بين الكتل الخارجية والداخلية.<br />
<span style="color: #cc0000; font-size: large;">غطاء حماية سريع</span> - يغلق التركيبات وكتلة المحطة الطرفية المستخدمة لتوصيل الكابلات الكهربائية. في بعض الطرازات ، لا يغطي الغطاء الواقي سوى طرف المحطة ، وتبقى وصلات الخنق في الخارج.<br />
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<span style="color: orange; font-size: x-large;"> الوحدة الداخلية :</span><br />
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<span style="color: #b45f06; font-size: large;">اللوحة الأمامية</span> عبارة عن جسم بلاستيكي يدخل عبره الهواء إلى الوحدة. يمكن إزالة اللوحة بسهولة لصيانة مكيف الهواء (فلاتر التنظيف ، إلخ.)<br />
<span style="font-size: large;"><span style="color: #b45f06;">المرشح الخشن</span> </span>عبارة عن شبكة بلاستيكية ومصممة لتأخير الغبار الخشن وشعر الحيوانات وما إلى ذلك. للتشغيل العادي لمرشح مكيف الهواء يجب تنظيفه مرتين على الأقل في الشهر.<br />
المبخر هو جهاز تدفئة يتم فيه تسخين الفريون البارد وتبخيره. يتم تبريد الهواء المنفوخ خلال المبرد وفقًا لذلك.<br />
<span style="color: #b45f06;"><span style="font-size: large;">الستائر الأفقية</span> </span>- تنظم اتجاه تدفق الهواء عموديًا. هذه الستائر لديها محرك كهربائي ويمكن تعديل موقفها مع جهاز تحكم عن بعد. بالإضافة إلى ذلك ، يمكن للستائر أن تقوم تلقائيًا بحركات تذبذبية لتوزيع منتظم لتدفق الهواء في جميع أنحاء الغرفة.<br />
لوحة المؤشرات - على اللوحة الأمامية لمكيف الهواء ، يتم تثبيت المؤشرات (LED) ، مما يدل على وضع التشغيل لمكيف الهواء والإشارة إلى الأعطال المحتملة.<br />
يمكن أن يكون المرشح الناعم من أنواع مختلفة: الفحم (يزيل الروائح الكريهة) ، الكهروستاتيكي (يحافظ على الغبار الناعم) ، إلخ. وجود أو عدم وجود مرشحات دقيقة ليس له أي تأثير على تشغيل مكيف الهواء.<br />
<span style="color: #b45f06;"><span style="font-size: large;">المروحة</span> </span>- لديها 3 - 4 سرعات دوران.<br />
<span style="color: #b45f06; font-size: large;">الستائر الرأسية</span> - تستخدم لضبط اتجاه تدفق الهواء أفقياً. في مكيفات الهواء المنزلية ، يمكن تعديل وضع هذه الستائر يدويًا فقط. القدرة على التكيف من جهاز التحكم عن بعد ليست سوى في بعض النماذج من مكيفات الهواء قسط.<br />
صينية التكثيف (غير مبينة في الشكل) - تقع تحت المبخر وتعمل على تجميع المكثفات (الماء المتشكل على سطح المبخر البارد). من البليت يتم تفريغ المياه إلى الخارج من خلال خرطوم الصرف.<br />
يقع عادةً <span style="color: #b45f06; font-size: large;">لوحة التحكم</span> (غير المبينة في الشكل) على الجانب الأيمن من الوحدة الداخلية. تحتوي هذه اللوحة على وحدة إلكترونية مزودة بمعالِج مركزي مركزي.<br />
توجد التجهيزات (غير المبينة في الشكل) في الجزء الخلفي السفلي من الوحدة الداخلية. ترتبط أنابيب النحاس التي تربط الكتل الخارجية والداخلية بها.<br />
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وهذه هى جميع مكونات المكيف الاسبيلت ارجوا الاشتراك فى المدونة ليصلكم كل جديد .<br />
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للتواصل واتساب : 249906087031+<br />
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mohammed saifhttp://www.blogger.com/profile/04808794259319186322noreply@blogger.com0tag:blogger.com,1999:blog-530905379816001374.post-23076206173373368822018-09-22T18:46:00.004-07:002018-09-22T18:46:59.677-07:00العزل الحراري للانابيب <div dir="rtl" style="text-align: right;" trbidi="on">
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<span style="color: #1900ff; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 25px;">يتم استخدام العزل الحراري في نظام تكييف الهواء في المقام الأول للحد من كسب الحرارة أو فقدان الحرارة من الأنابيب. وتشمل العوامل الأخرى منع تجمد بخار الماء والتكثيف على السطح البارد.</span></span></h1>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgTUlu0lTJQgOZo3keR0Yc8_7dkAA6E6xuoyK2XR5zwKEQeIZWSVc_IFsaw_sj7Dp1cp66sqTh9g7Sr0VG_Lq7_dXgW1S2ey0Qy4GMRja8ROdMkQpu080C4opCbyRPz3cIC6wmsaaNkZeLZ/s1600/18.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="199" data-original-width="253" height="503" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgTUlu0lTJQgOZo3keR0Yc8_7dkAA6E6xuoyK2XR5zwKEQeIZWSVc_IFsaw_sj7Dp1cp66sqTh9g7Sr0VG_Lq7_dXgW1S2ey0Qy4GMRja8ROdMkQpu080C4opCbyRPz3cIC6wmsaaNkZeLZ/s640/18.jpg" width="640" /></a></div>
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<span style="color: #1900ff; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 25px;">يجب الحفاظ على بخار الماء من الهواء أو المنطقة المحيطة من دخول الجانب البارد من الأنبوب لمنع تكثف الرطوبة من الهواء على السطح الخارجي للأنابيب الباردة</span></span></h1>
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<span style="color: #1900ff; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 25px;">قد يسبب التكثيف أضرارًا للمناطق المجاورة مثل السجاد أو المفروشات الأخرى. وبالتالي ، يجب أن يعمل العزل كحاجز بخار.</span></span></h1>
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<span style="color: #1900ff; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 25px;">كما أنه يساعد على الحد من مستوى الضوضاء ، وامتصاص الاهتزازات الناتجة عن النظام ، ومنع انتشار الحريق وإضافة القوة الهيكلية للجدران أو السقوف.</span></span></h1>
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<span style="color: #1900ff; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 25px;">كما يمكن للمواد التي تم اختيارها بشكل جيد أن تحمي الأنابيب التي يتم عزلها من الظروف البيئية القاسية مثل الأشعة فوق البنفسجية ، والملح ، والمياه ، والغبار ، والمواد الكيميائية ، والنفط. قد تشمل الخصائص الأخرى القدرة على منع النمو أو الفيروسات والبكتيريا والفطريات.</span></span></h1>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjEoNiOuFpy3uHV3IKmSxccGkRdyrTWh_iiOmCQH_M1S9j3L7RO-xkCuCGj6SKI-RKXOwVH36UZXTe0S3mmPKK6nRh1vcltsLb1jx6XKX9vwBnGCJftaBuxjTEvI7SzkQsY_8ikPzTg_qoi/s1600/17.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="210" data-original-width="241" height="346" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjEoNiOuFpy3uHV3IKmSxccGkRdyrTWh_iiOmCQH_M1S9j3L7RO-xkCuCGj6SKI-RKXOwVH36UZXTe0S3mmPKK6nRh1vcltsLb1jx6XKX9vwBnGCJftaBuxjTEvI7SzkQsY_8ikPzTg_qoi/s400/17.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">صورة توضح عازل حرارى لمواسير المياه المبرده carbon steel<br />www.dreamworldfly.blogspot.com</td></tr>
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<span style="color: #1900ff; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 25px;">خصائص العزل</span></span></h1>
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<span style="color: #1900ff; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 25px;">الموصلية الحرارية المنخفضة.</span></span></h1>
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<span style="color: #1900ff; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 25px;">قوة معقولة</span></span></h1>
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<span style="color: #1900ff; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 25px;">غير قابلة للاحتراق.</span></span></h1>
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<span style="color: #1900ff; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 25px;">مقاومة للفطريات مثل التي تعتمد على معيار ASTM G21.</span></span></h1>
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<span style="color: #1900ff; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 25px;">مقاومة ممتازة للأوزون</span></span></h1>
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<span style="color: #1900ff; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 25px;">مقاومة ممتازة للأشعة فوق البنفسجية.</span></span></h1>
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<span style="color: #1900ff; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 25px;">لا تتدهور أو تتعفن مع مرور الوقت.</span></span></h1>
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<span style="color: #1900ff; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 25px;">يمكن تصنيع مواد عزل الأنابيب من المطاط أو الصوف أو الألياف الزجاجية أو الفلين. البولي يوريثين أو P.U. هي مادة اصطناعية شائعة الاستخدام هذه الأيام بسبب الموصلية الحرارية المنخفضة وخصائص جيدة أخرى.</span></span></h1>
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<span style="color: #1900ff; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 25px;">موقع العزل في نظام التبريد</span></span></h1>
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<span style="color: #1900ff; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 25px;">يتم عزل Cold Line لمنع تسرب الهواء إلى العزل الذي يمكن أن يسبب تكثيف الرطوبة في الأنبوب.</span></span></h1>
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<span style="color: #1900ff; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 25px;">يتم عزل خط السحب لمنع فقد القدرة أو التعرق بسبب كسب الحرارة. يتسبب كسب الحرارة في زيادة الحمل على المكثف وبالتالي تقليل السعة الكلية لنظام تكييف الهواء.</span></span></h1>
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<span style="color: #1900ff; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 25px;">لا يتطلب خط السائل أي عزل لأنه في درجة حرارة أعلى من الهواء المحيط. من المستحسن فقدان الحرارة للهواء المحيط لأنه يحسن قدرة النظام.</span></span></h1>
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<span style="color: #1900ff; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 25px;">لا يتطلب خط التفريغ العزل لأن فقدان الحرارة يزيل الحمل من المكثف. هذا يساعد على تحسين أداء الضاغط.</span></span></h1>
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mohammed saifhttp://www.blogger.com/profile/04808794259319186322noreply@blogger.com1tag:blogger.com,1999:blog-530905379816001374.post-19241261945067760432018-09-22T17:25:00.001-07:002019-01-14T12:31:41.380-08:00كيفية اختيار أفضل مكيف لمنزلك: مقارنة أنظمة التكييف :<div dir="rtl" style="text-align: right;" trbidi="on">
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">عندما تبدأ درجة الحرارة في الصعود ، من السهل أن ترى لماذا يعتبر تكييف
الهواء ضرورة راحة منزلية ، خاصة إذا كنت تعيش في منطقة ذات رطوبة عالية او منطقه
صحراوية .</span><o:p></o:p></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">هناك أربعة أنواع رئيسية من وحدات وأنظمة تكييف الهواء المنزلية التي
تعمل على مبدأ إزالة الحرارة. ومع ذلك ، عندما يتعلق الأمر بمستويات الكفاءة والجماليات
والقدرة على توفير الراحة ، يمكن أن تختلف النتائج. سنلقي نظرة على إيجابيات وسلبيات
كل وحدة أو نظام لمساعدتك في تحديد الخيار الأفضل لمنزلك.</span><o:p></o:p></div>
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<span style="color: #cc0000;">-Window-<span dir="RTL"></span><span dir="RTL"></span><span dir="RTL" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><span dir="RTL"></span><span dir="RTL"></span> <span lang="AR-SA">مكيفات
الهواء النافذة</span></span><span dir="LTR"></span><span dir="LTR"></span><span dir="LTR"></span><span dir="LTR"></span>-1</span><o:p></o:p></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><br /></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">وحدات النوافذ هي نوع شائع من معدات التبريد المصممة لتناسب النوافذ المزدوجة
والمغلقة. يتم تثبيتها بشكل شائع في الشقق التي تفتقر إلى التكييف المركزي ، أو أنها
يمكن أن تعطي دفعة تبريد للغرف الفردية في المنازل الكبيرة</span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">.</span><o:p></o:p></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">فوائد استخدام مكيف هواء النافذة</span><o:p></o:p></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">مكيفات الهواء النافذة صغيرة نسبياً ، محمولة إلى حد ما وسهلة التركيب
دون مساعدة المحترفين. إذا كان لديك قيود على الميزانية ، فإن وحدة النافذة هي أرخص
خيار من التجهيزات لإضافة مكيفات الهواء إلى منزلك. ونماذج اليوم أكثر فعالية بنسبة
30٪ من تلك التي صنعت قبل عقد واحد فقط. كما أنها تأتي مع ضمانات لمدة تصل إلى خمس
سنوات لتوفر لك راحة البال عند إجراء عملية الشراء.</span><o:p></o:p></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">مساوئ استخدام مكيف هواء النافذة</span><o:p></o:p></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">تذكر فقط أن مكيفات الهواء في النوافذ لا تهدف إلى تبريد المنزل بأكمله.
حتى إذا كنت تعيش في شقة ، فستحتاج إلى وحدات متعددة للحفاظ على راحة كل غرفة. كل وحدة
تقوم بتثبيت يضعف قدرتك على تشغيل هذه النافذة وعرقلة نظرتك للخارج. عليك أيضا التعامل
مع ضجيج الضاغط الذي يعمل على الأذن مباشرة</span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">.</span><o:p></o:p></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">إذا قررت أنك بحاجة إلى وحدة كبيرة ، فقد تجد صعوبة في تركيبها وإزالتها
للتخزين في فصل الشتاء. وتشمل العوامل التي يمكن أن تضعف كفاءة مكيف الهواء في النوافذ
السقوف العالية والكثير من النوافذ والأبواب والتعرض لأشعة الشمس العالية وتبريد غرفة
في الطابق العلوي.</span><o:p></o:p></div>
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<span style="color: #cc0000;">-Stand-<span dir="RTL"></span><span dir="RTL"></span><span dir="RTL" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><span dir="RTL"></span><span dir="RTL"></span> <span lang="AR-SA">مكيفات
الهواء المحمولة</span></span><span dir="LTR"></span><span dir="LTR"></span><span dir="LTR"></span><span dir="LTR"></span>-2</span><o:p></o:p></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiNbm0TV7DZCG-tabaVPv1h6sXCetL6FG5WTWaFYa328-4ZXddpXNCaEG5krUzE_l204GN_QAsk3q7STV1dTIYlF81GmCK8iSaympOaBhT4z_wQgw18-LRjaoD7WX8B1tOiHFmyo9jejj5g/s1600/12.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="600" data-original-width="367" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiNbm0TV7DZCG-tabaVPv1h6sXCetL6FG5WTWaFYa328-4ZXddpXNCaEG5krUzE_l204GN_QAsk3q7STV1dTIYlF81GmCK8iSaympOaBhT4z_wQgw18-LRjaoD7WX8B1tOiHFmyo9jejj5g/s400/12.jpg" width="243" /></a></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><br /></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">هذه الوحدات تشبه مكيفات الهواء النافذة ، لكنها تقف على الأرض بدلا من
الذهاب مباشرة إلى النافذة. ترسم الوحدة الهواء ، وتزيل الحرارة والرطوبة ، وتعيد الهواء
البارد والجاف إلى منزلك. يتم تهوئة الهواء الحار والرطب عبر خرطوم عادم يخرج من النافذة.
يعد هذا الخيار أفضل فقط لوحدات النوافذ إذا كان لديك نوع خاطئ من النوافذ ، أو أنك
غير قادر على رفع مكيفات هواء النوافذ الثقيلة</span><span dir="LTR"></span><span dir="LTR"></span><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">فوائد استخدام مكيف هواء محمول</span><o:p></o:p></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">تكون مكيفات الهواء المحمولة أسهل في الإعداد من وحدات النافذة. تدور
وحدات الكلمة حول العجلات بحيث يمكنك وضعها بشكل صحيح.</span><o:p></o:p></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">مساوئ استخدام مكيف الهواء المحمول</span><o:p></o:p></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">وفقًا لتقارير المستهلك ، فإن مكيفات الهواء المحمولة تميل فقط إلى توفير
نصف قدرة التبريد التي تدعيها ، مما قد يجعلك تشعر بالانتفاخ والعرق حتى عندما تعمل
الوحدة بدون توقف. كما أنها أكثر تكلفة وأقل كفاءة من وحدات النوافذ ذات الحجم المماثل
، مما يدفع تكاليف الشراء والتشغيل إلى أعلى. اﻟﻀﻮﺿﺎء هﻮ ﻋﺎﻣﻞ ﺁﺧﺮ ، وﻣﻌﻈﻢ ﻣﻜﻴﻔﺎت اﻟﻬﻮاء
اﻟﻤﺤﻤﻮﻟﺔ ﻟﺪﻳﻬﺎ ﺧﺰاﻧﺎت ﻣﻴﺎﻩ ﻳﺠﺐ ﻋﻠﻴﻚ ﺗﺼﺮﻳﻔﻬﺎ ﻳﺪوﻳًﺎ ﺣﻴﺚ ﺗﺰﻳﻞ اﻟﻮﺣﺪة اﻟﺮﻃﻮﺑﺔ اﻟﺰاﺋﺪة
ﻣﻦ اﻟﻬﻮاء</span><span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-language: AR-EG; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">.</span><span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR-EG; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-language: AR-EG; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><br /></span></div>
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<span style="color: #cc0000;"> - Multi spilt -<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">مكيفات هواء صغيرة مجزأة بدون مجاري</span><span dir="LTR"></span><span dir="LTR"></span><span dir="LTR"></span><span dir="LTR"></span> -3</span><o:p></o:p></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhFkL9yn1Q-rkr770YBNFItJu6mkkKYsvM6BL7m0OlILC4lXRpKR1Pd8C0G0SdGbu5GYJ-Vpm7uy8HTRhzvdWoc9Gr2J_3rVk3UAEx3TPWbBLGcM8W-hXMOQAVH5oxQV-ZwJLpPIfnYXZ5l/s1600/13.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><br /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhFkL9yn1Q-rkr770YBNFItJu6mkkKYsvM6BL7m0OlILC4lXRpKR1Pd8C0G0SdGbu5GYJ-Vpm7uy8HTRhzvdWoc9Gr2J_3rVk3UAEx3TPWbBLGcM8W-hXMOQAVH5oxQV-ZwJLpPIfnYXZ5l/s1600/13.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><br /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhFkL9yn1Q-rkr770YBNFItJu6mkkKYsvM6BL7m0OlILC4lXRpKR1Pd8C0G0SdGbu5GYJ-Vpm7uy8HTRhzvdWoc9Gr2J_3rVk3UAEx3TPWbBLGcM8W-hXMOQAVH5oxQV-ZwJLpPIfnYXZ5l/s1600/13.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="200" data-original-width="336" height="237" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhFkL9yn1Q-rkr770YBNFItJu6mkkKYsvM6BL7m0OlILC4lXRpKR1Pd8C0G0SdGbu5GYJ-Vpm7uy8HTRhzvdWoc9Gr2J_3rVk3UAEx3TPWbBLGcM8W-hXMOQAVH5oxQV-ZwJLpPIfnYXZ5l/s400/13.jpg" width="400" /></a></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><br /></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><br /></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><br /></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">إن شق صغير مجدول هو في الأساس مضخة حرارية بدون مجاري هواء. لديها اثنين
من المكونات الرئيسية. الأول هو ضاغط في الهواء الطلق ، على غرار تلك الموجودة في مكيفات
الهواء المركزية. والثاني هو وحدة المبخر الداخلي ومعالج الهواء الذي يتصاعد إلى الجدار
أو السقف. وتربط القناة التي تسير عبر فتحة مغلقة في الجدار الوحدتين معاً</span><span dir="LTR"></span><span dir="LTR"></span><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">تم تصميم مكيفات الهواء ذات الانقسام الصغير بدون مجاريات لتبريد المنازل
القديمة بدون مجاري الهواء ، والمنازل الصغيرة والإضافات حيث لا يمكن إضافة مجاري الهواء.
تحقق بعض طرز</span><span dir="LTR"></span><span dir="LTR"></span><span dir="LTR"></span><span dir="LTR"></span> AC <span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">غير المجدية أعلى تصنيفات كفاءة لأي نوع
من أنظمة تكييف الهواء.</span><o:p></o:p></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">فوائد استخدام مكيف هواء صغير مجزأ بدون مجرى هواء</span><o:p></o:p></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">وتتمثل الميزة الرئيسية للتقسيمات الصغيرة في قدرتها على توفير التبريد
المرن للأجزاء الفردية من منزلك ، مع الحفاظ على الحجم الصغير والكفاءة في استخدام
الطاقة. إنها أقرب ما يمكن أن تصل إلى التكييف المركزي دون الحاجة إلى تمزيق السقف
والجدران لتركيب مجاري الهواء. بالإضافة إلى ذلك ، بما أن الشقوق الصغيرة هي نوع من
المضخات الحرارية ، فإنها يمكن أن توفر أيضًا التدفئة المنزلية في الشتاء</span><span dir="LTR"></span><span dir="LTR"></span><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">كمكافأة إضافية ، تعمل التقسيم الصغير بلا مجرى بهدوء مثل المروحة العادية.
بما أن الضاغط موجود في الخارج ، فهذه الوحدات أكثر هدوءًا من النافذة أو مكيف الهواء
المنزلي المحمول. بالإضافة إلى ذلك ، مع عدم الحاجة إلى الوصول إلى النافذة أثناء التثبيت
، توفر الشقوق الصغيرة أمن منزلي أفضل ، رؤية بدون عائق من الخارج ، والقدرة على تشغيل
النافذة وقتما تشاء</span><span dir="LTR"></span><span dir="LTR"></span><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">مساوئ استخدام مكيف هواء صغير مجزأ بدون مجاري هواء</span><o:p></o:p></div>
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<span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR-EG; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">ا</span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">لانقسامات المصغرة
هي أكثر تكلفة من النوافذ أو الوحدات المحمولة. أنت أيضًا بحاجة إلى محترف لإجراء التثبيت
، والذي يتضمن حفر ثقب ثلاثي الأبعاد في الجدار لربط المكونات الداخلية والخارجية.
تحتاج أيضًا إلى أخذ اعتبارات التصميم الداخلي في الحسبان نظرًا لأن الوحدة تتصاعد
إلى الحائط أو السقف في الغرفة التي ترغب في تسخينها أو تبريدها</span><span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-language: AR-EG; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">.</span><span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR-EG; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><o:p></o:p></span></div>
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</span></span><!--[endif]--><span style="color: #cc0000;"><span dir="LTR"></span>Centeral Condition - <span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">نظام تكييف مركزي</span><span dir="LTR"></span><span dir="LTR"></span><span dir="LTR"></span><span dir="LTR"></span>- 4<o:p></o:p></span></div>
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<span style="color: #cc0000;">(minispilt - chiller –VRV )</span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><o:p></o:p></span></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgMnO0Y3ZNbjbp0N90EkktUT8P2SlMVcQNCEk7QHEryEtSk_hT99nlRQ2BstkjWh5gVF3_HJ-RMFjzbrxQ5Vh32yVp_I3ZGR5ZtymmV6T8mZ_yf0Yn7VadUrJ3qUiOTdnS5mVUkRJsotkJn/s1600/14.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="168" data-original-width="300" height="224" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgMnO0Y3ZNbjbp0N90EkktUT8P2SlMVcQNCEk7QHEryEtSk_hT99nlRQ2BstkjWh5gVF3_HJ-RMFjzbrxQ5Vh32yVp_I3ZGR5ZtymmV6T8mZ_yf0Yn7VadUrJ3qUiOTdnS5mVUkRJsotkJn/s400/14.jpg" width="400" /></a></div>
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<span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-language: AR-EG; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><br /></span></div>
<div align="right" class="MsoNormal">
<span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-language: AR-EG; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"> </span><span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">هذا الخيار هو الطريقة الأكثر شمولاً لتبريد
منزلك. ينطوي على توزيع الهواء المبرد من خلال مجاري الهواء مع سجلات العودة والعرض
في كل غرفة. توجد جميع مكونات تكييف الهواء في الخارج ، باستثناء معالج الهواء ، إذا
كنت تبحث عن تبريد منزلي بالكامل ، ولديك بالفعل مجاري هواء ، فهذا هو الخيار الأكثر
شيوعًا</span><span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-language: AR-EG; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">.</span><o:p></o:p></div>
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<br /></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">فوائد استخدام نظام</span><span dir="LTR"></span><span dir="LTR"></span><span dir="LTR"></span><span dir="LTR"></span>
AC <span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">مركزي</span><o:p></o:p></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">تكييف الهواء المركزي هو الطريقة الأكثر فعالية للحفاظ على منزلك كله
بارد. يمكنك أن تتوقع فواتير طاقة أقل إلى جانب راحة داخلية أفضل ودرجات حرارة أقل
ودرجة رطوبة أقل. مع جميع مكونات التكييف الموجودة بالخارج ، يمكنك الحفاظ على البرودة
مع نظام صامت غير مرئي.</span><span dir="RTL" lang="AR-EG" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-language: AR-EG; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><o:p></o:p></span></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">التثبيت سهل إلى حد ما إذا كان لديك بالفعل مجاري هواء ، ولكنك ستظل بحاجة
إلى توظيف محترف لهذا المنصب. ومع ذلك ، حيث أنه يصبح لاعبا اساسيا دائما في منزلك
، فهو استثمار يضيف قيمة له.<o:p></o:p></span></div>
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<br /></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">إن اعتبارك النهائي عند مقارنة أنظمة تكييف الهواء هو الحجم الذي تحتاجه.
إذا اخترت وحدة أصغر حجمًا ، فلن تستمر في الأيام الأكثر سخونة. إذا قمت بتثبيت وحدة
كبيرة الحجم ، فستقوم بدورة قصيرة ، والتي تلبس الأجزاء بشكل أسرع ولا تعطي الوحدة
فرصة لتجفيف المساحة</span><span dir="LTR"></span><span dir="LTR"></span><span dir="LTR"></span><span dir="LTR"></span>.<o:p></o:p></div>
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<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 11.0pt; line-height: 115%;">ان اختيار نظام التكييف الصحيح والتصميم الجيد
يوفر الكفاءة التبريدية والراحه المطلوبة ويقوم بتقليل التكاليف مقدما او مؤخرا.</span><br />
<span dir="RTL" lang="AR-SA" style="font-family: "arial" , "sans-serif"; font-size: 11.0pt; line-height: 115%;"><br /></span>
<span dir="RTL" lang="AR-SA" style="color: red; font-family: "arial" , "sans-serif"; font-size: 11.0pt; line-height: 115%;"><a href="https://khamsat.com/designing/presentation/955434-%D8%AD%D8%B3%D8%A7%D8%A8-%D8%A7%D8%AD%D9%85%D8%A7%D9%84-%D9%88%D8%AA%D8%B5%D9%85%D9%8A%D9%85-%D8%AE%D8%B1%D8%B7-%D8%A7%D9%84%D8%AA%D9%83%D9%8A%D9%8A%D9%81-%D8%A7%D9%84%D9%85%D8%B1%D9%83%D8%B2%D9%89-16-%D9%85%D8%AA%D8%B1-%D9%85%D8%B1%D8%A8%D8%B9-%D8%A8%D9%89-5" target="_blank">للتواصل او طلب خدمه يرجى الضغط هنا</a></span></div>
mohammed saifhttp://www.blogger.com/profile/04808794259319186322noreply@blogger.com0tag:blogger.com,1999:blog-530905379816001374.post-2551317544014535332018-07-25T04:05:00.001-07:002018-07-25T04:05:26.606-07:00Piping<div dir="rtl" style="text-align: right;" trbidi="on">
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjNO_stveeAjk8qidWwV39VhVrltaueLgO-rQEyHAP5OPuS0WBe-FukU9fSAqzsI4Zx88Fxi4tVTRL70zDNWrsQD-gc3BlJ1WTminaM5rOYv6L0YPirHVyo8YcG8l_KouUg5UybIAQ_wu5B/s1600/ToolRaid%252B12.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="225" data-original-width="225" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjNO_stveeAjk8qidWwV39VhVrltaueLgO-rQEyHAP5OPuS0WBe-FukU9fSAqzsI4Zx88Fxi4tVTRL70zDNWrsQD-gc3BlJ1WTminaM5rOYv6L0YPirHVyo8YcG8l_KouUg5UybIAQ_wu5B/s400/ToolRaid%252B12.jpg" width="400" /></a></div>
<div style="text-align: left;">
<span style="font-size: large;"><br /></span></div>
<div style="text-align: left;">
<span style="font-size: large;">Refrigerant Piping</span></div>
<div style="text-align: left;">
<span style="font-size: large;">One of the Fundamental Series</span></div>
<div style="text-align: left;">
<span style="font-size: large;">A publication of Trane, a business</span></div>
<div style="text-align: left;">
<span style="font-size: large;">of American Standard Companies</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Preface</span></div>
<div style="text-align: left;">
<span style="font-size: large;">© 2002 American Standard Inc. All rights reserved</span></div>
<div style="text-align: left;">
<span style="font-size: large;">ii TRG-TRC006-EN</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Trane believes that it is incumbent on manufacturers to serve the industry by</span></div>
<div style="text-align: left;">
<span style="font-size: large;">regularly disseminating information gathered through laboratory research,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">testing programs, and field experience.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The Trane Air Conditioning Clinic series is one means of knowledge sharing. It</span></div>
<div style="text-align: left;">
<span style="font-size: large;">is intended to acquaint a technical audience with various fundamental aspects</span></div>
<div style="text-align: left;">
<span style="font-size: large;">of heating, ventilating, and air conditioning (HVAC). We have taken special care</span></div>
<div style="text-align: left;">
<span style="font-size: large;">to make the clinic as uncommercial and straightforward as possible.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Illustrations of Trane products only appear in cases where they help convey the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">message contained in the accompanying text.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">This particular clinic introduces the reader to refrigerant piping.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Refrigerant Piping</span></div>
<div style="text-align: left;">
<span style="font-size: large;"><br /></span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period one</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Refrigerant Piping Requirements</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The focus of this clinic is on the design and installation of the interconnecting</span></div>
<div style="text-align: left;">
<span style="font-size: large;">piping for vapor-compression refrigeration systems. Reviewing the physical</span></div>
<div style="text-align: left;">
<span style="font-size: large;">changes that the refrigerant undergoes within the refrigeration cycle will help</span></div>
<div style="text-align: left;">
<span style="font-size: large;">demonstrate certain demands that the piping design must meet.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">This clinic focuses on systems that use Refrigerant-22 (R-22). While the general</span></div>
<div style="text-align: left;">
<span style="font-size: large;">requirements are the same for systems that use other refrigerants, velocities</span></div>
<div style="text-align: left;">
<span style="font-size: large;">and pressure drops will differ.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 3 illustrates a basic vapor-compression refrigeration cycle. Refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">enters the evaporator in the form of a cool, low-pressure mixture of liquid and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">vapor (A). Heat is transferred to the refrigerant from the relatively warm air that</span></div>
<div style="text-align: left;">
<span style="font-size: large;">is being cooled, causing the liquid refrigerant to boil. The resulting refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">vapor (B) is then pumped from the evaporator by the compressor, which</span></div>
<div style="text-align: left;">
<span style="font-size: large;">increases the pressure and temperature of the vapor.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period one</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Refrigerant Piping Requirements</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Refrigerant Piping Requirements</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The resulting hot, high-pressure refrigerant vapor (C) enters the condenser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">where heat is transferred to ambient air, which is at a lower temperature than</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the refrigerant. Inside the condenser, the refrigerant vapor condenses into a</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid and is subcooled. This liquid refrigerant (D) then flows from the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condenser to the expansion device. This device creates a pressure drop that</span></div>
<div style="text-align: left;">
<span style="font-size: large;">reduces the pressure of the refrigerant to that of the evaporator. At this low</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pressure, a small portion of the refrigerant boils (or flashes), cooling the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">remaining liquid refrigerant to the desired evaporator temperature. The cool</span></div>
<div style="text-align: left;">
<span style="font-size: large;">mixture of liquid and vapor refrigerant (A) enters the evaporator to repeat the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">cycle.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The vapor-compression refrigeration cycle, and the four major components of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the refrigeration system (evaporator, compressor, condenser, and expansion</span></div>
<div style="text-align: left;">
<span style="font-size: large;">device), are discussed in more detail in separate clinics. Refer to the list of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">references at the end of Period Six.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">These individual components are connected by refrigerant piping. The suction</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line connects the evaporator to the compressor, the discharge line connects the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor to the condenser, and the liquid line connects the condenser to the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">expansion device. The expansion device is typically located at the end of the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid line, at the inlet to the evaporator.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">There is more to the design of refrigerant piping than moving refrigerant from</span></div>
<div style="text-align: left;">
<span style="font-size: large;">one component to another. Regardless of the care exercised in selection and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">application of the components of the refrigeration system, operational</span></div>
<div style="text-align: left;">
<span style="font-size: large;">problems may be encountered if the interconnecting piping is improperly</span></div>
<div style="text-align: left;">
<span style="font-size: large;">designed or installed.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Interconnecting Refrigerant Piping</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condenser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">evaporator</span></div>
<div style="text-align: left;">
<span style="font-size: large;">expansion</span></div>
<div style="text-align: left;">
<span style="font-size: large;">device</span></div>
<div style="text-align: left;">
<span style="font-size: large;">discharge</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Refrigerant Piping Requirements</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">When a refrigeration system includes field-assembled refrigerant piping to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">connect two or more of the components, the primary design goals are generally</span></div>
<div style="text-align: left;">
<span style="font-size: large;">to maximize system reliability and minimize installed cost. To accomplish these</span></div>
<div style="text-align: left;">
<span style="font-size: large;">two goals, the design of the interconnecting refrigerant piping must meet the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">following requirements:</span></div>
<div style="text-align: left;">
<span style="font-size: large;"> Return oil to the compressor at the proper rate, at all operating conditions</span></div>
<div style="text-align: left;">
<span style="font-size: large;"> Ensure that only liquid refrigerant (no vapor) enters the expansion device</span></div>
<div style="text-align: left;">
<span style="font-size: large;"> Minimize system capacity loss that is caused by pressure drop through the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">piping and accessories</span></div>
<div style="text-align: left;">
<span style="font-size: large;"> Minimize the total refrigerant charge in the system to improve reliability and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">minimize installed cost</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The first requirement is to ensure that oil is returned to the compressor at all</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Refrigerant Piping Requirements</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Return oil to compressor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Ensure that only liquid refrigerant enters</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the expansion device</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Minimize system capacity loss</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Minimize refrigerant charge</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 5</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Scroll Compressor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">stationary</span></div>
<div style="text-align: left;">
<span style="font-size: large;">scroll</span></div>
<div style="text-align: left;">
<span style="font-size: large;">driven</span></div>
<div style="text-align: left;">
<span style="font-size: large;">scroll</span></div>
<div style="text-align: left;">
<span style="font-size: large;">intake</span></div>
<div style="text-align: left;">
<span style="font-size: large;">discharge</span></div>
<div style="text-align: left;">
<span style="font-size: large;">intake</span></div>
<div style="text-align: left;">
<span style="font-size: large;">discharge</span></div>
<div style="text-align: left;">
<span style="font-size: large;">port</span></div>
<div style="text-align: left;">
<span style="font-size: large;">motor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">shaft</span></div>
<div style="text-align: left;">
<span style="font-size: large;">seal</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 6</span></div>
<div style="text-align: left;">
<span style="font-size: large;">4 TRG-TRC006-EN</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period one</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Refrigerant Piping Requirements</span></div>
<div style="text-align: left;">
<span style="font-size: large;">operating conditions. Oil is used to lubricate and seal the moving parts of a</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor. For example, the scroll compressor shown in Figure 6 on page 3</span></div>
<div style="text-align: left;">
<span style="font-size: large;">uses two scroll configurations, mated face-to-face, to compress the refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">vapor. The tips of these scrolls are fitted with seals that, along with a thin layer</span></div>
<div style="text-align: left;">
<span style="font-size: large;">of oil, prevent the compressed refrigerant vapor from escaping through the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">mating surfaces. Similarly, other types of compressors also rely on oil for</span></div>
<div style="text-align: left;">
<span style="font-size: large;">lubrication and for providing a seal when compressing the refrigerant vapor.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Characteristically, some of this lubricating oil is pumped along with the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant throughout the rest of the system. While this oil has no function</span></div>
<div style="text-align: left;">
<span style="font-size: large;">anywhere else in the system, the refrigerant piping must be designed and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">installed so that this oil returns to the compressor at the proper rate, at all</span></div>
<div style="text-align: left;">
<span style="font-size: large;">operating conditions.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Returning to the system schematic, droplets of oil are pumped out of the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor along with the hot, high-pressure refrigerant vapor. The velocity of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the refrigerant inside the discharge line must be high enough to carry the small</span></div>
<div style="text-align: left;">
<span style="font-size: large;">oil droplets through the pipe to the condenser.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Inside the condenser, the refrigerant vapor condenses into a liquid. Liquid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant and oil have an affinity for each other, so the oil easily moves along</span></div>
<div style="text-align: left;">
<span style="font-size: large;">with the liquid refrigerant. From the condenser, this mixture of liquid refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">and oil flows through the liquid line to the expansion device.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Next, the refrigerant–oil mixture is metered through the expansion device into</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the evaporator, where the liquid refrigerant absorbs heat and vaporizes. Again,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the velocity of the refrigerant vapor inside the suction line must be high enough</span></div>
<div style="text-align: left;">
<span style="font-size: large;">to carry the droplets of oil through the pipe back to the compressor.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Without adequate velocity and proper pipe installation, oil may be trapped out</span></div>
<div style="text-align: left;">
<span style="font-size: large;">in the system. If this condition is severe enough, the reduced oil level in the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor could cause lubrication problems and, potentially, mechanical</span></div>
<div style="text-align: left;">
<span style="font-size: large;">failure.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Return Oil to Compressors</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condenser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">evaporator</span></div>
<div style="text-align: left;">
<span style="font-size: large;">expansion</span></div>
<div style="text-align: left;">
<span style="font-size: large;">device</span></div>
<div style="text-align: left;">
<span style="font-size: large;">discharge</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">warm</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">hot</span></div>
<div style="text-align: left;">
<span style="font-size: large;">vapor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">cool</span></div>
<div style="text-align: left;">
<span style="font-size: large;">vapor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 7</span></div>
<div style="text-align: left;">
<span style="font-size: large;">TRG-TRC006-EN 5</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period one</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Refrigerant Piping Requirements</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The second requirement of the refrigerant piping design is to ensure that only</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid refrigerant enters the expansion device. There are several types of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">expansion devices, including expansion valves (thermostatic or electronic),</span></div>
<div style="text-align: left;">
<span style="font-size: large;">capillary tubes, and orifices.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">In addition to maintaining the pressure difference between the high-pressure</span></div>
<div style="text-align: left;">
<span style="font-size: large;">(condenser) and low-pressure (evaporator) sides of the system, a</span></div>
<div style="text-align: left;">
<span style="font-size: large;">thermostatic expansion valve (TXV) also controls the quantity of liquid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant that enters the evaporator. This ensures that the refrigerant will be</span></div>
<div style="text-align: left;">
<span style="font-size: large;">completely vaporized within the evaporator, and maintains the proper amount</span></div>
<div style="text-align: left;">
<span style="font-size: large;">of superheat in the system.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Inside the condenser, after all of the refrigerant vapor has condensed into</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid, the refrigerant is subcooled to further lower its temperature. This</span></div>
<div style="text-align: left;">
<span style="font-size: large;">subcooled liquid refrigerant leaves the condenser (A) and experiences a</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pressure drop as it flows through the liquid line and accessories, such as a filter</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Thermostatic Expansion Valve (TXV)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">external equalizer</span></div>
<div style="text-align: left;">
<span style="font-size: large;">remote</span></div>
<div style="text-align: left;">
<span style="font-size: large;">bulb</span></div>
<div style="text-align: left;">
<span style="font-size: large;">evaporator</span></div>
<div style="text-align: left;">
<span style="font-size: large;">TXV</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">vapor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">distributor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 8</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Subcooling</span></div>
<div style="text-align: left;">
<span style="font-size: large;">A B</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pressure</span></div>
<div style="text-align: left;">
<span style="font-size: large;">enthalpy</span></div>
<div style="text-align: left;">
<span style="font-size: large;">subcooling</span></div>
<div style="text-align: left;">
<span style="font-size: large;">mixture of liquid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">and vapor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">saturated</span></div>
<div style="text-align: left;">
<span style="font-size: large;">vapor curve</span></div>
<div style="text-align: left;">
<span style="font-size: large;">saturated</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid curve</span></div>
<div style="text-align: left;">
<span style="font-size: large;">expansion</span></div>
<div style="text-align: left;">
<span style="font-size: large;">device</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condenser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">evaporator</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 9</span></div>
<div style="text-align: left;">
<span style="font-size: large;">6 TRG-TRC006-EN</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period one</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Refrigerant Piping Requirements</span></div>
<div style="text-align: left;">
<span style="font-size: large;">drier and solenoid valve, installed upstream of the TXV. On the pressureenthalpy chart, Figure 9 on page 5, this moves the condition of the refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">toward the saturated liquid curve (B). If this pressure drop is high enough, or if</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the refrigerant has not been subcooled enough by the condenser, a small</span></div>
<div style="text-align: left;">
<span style="font-size: large;">portion of the refrigerant may boil (or flash), resulting in a mixture of liquid and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">vapor (C) entering the expansion device.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The presence of refrigerant vapor upstream of the expansion device is very</span></div>
<div style="text-align: left;">
<span style="font-size: large;">undesirable. Bubbles of vapor displace liquid in the port of the TXV, reducing</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the flow rate of liquid through the valve, therefore substantially reducing the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">capacity of the evaporator. This results in erratic valve operation.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The design of the piping system must ensure that only liquid refrigerant (no</span></div>
<div style="text-align: left;">
<span style="font-size: large;">vapor) enters the expansion device. This requires that the condenser provide</span></div>
<div style="text-align: left;">
<span style="font-size: large;">adequate subcooling at all system operating conditions, and that the pressure</span></div>
<div style="text-align: left;">
<span style="font-size: large;">drop through the liquid line and accessories not be high enough to cause</span></div>
<div style="text-align: left;">
<span style="font-size: large;">flashing. Subcooling allows the liquid refrigerant to experience some pressure</span></div>
<div style="text-align: left;">
<span style="font-size: large;">drop as it flows through the liquid line, without the risk of flashing.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The third requirement of the refrigerant piping design is to minimize system</span></div>
<div style="text-align: left;">
<span style="font-size: large;">capacity loss. To achieve the maximum capacity from the system, the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant must circulate through the system as efficiently as possible. This</span></div>
<div style="text-align: left;">
<span style="font-size: large;">involves minimizing any pressure drop through the piping and other system</span></div>
<div style="text-align: left;">
<span style="font-size: large;">components.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Whenever a fluid flows inside a pipe, a characteristic pressure drop is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">experienced. Pressure drop is caused by friction between the moving liquid (or</span></div>
<div style="text-align: left;">
<span style="font-size: large;">vapor) and the inner walls of the pipe. The total pressure drop depends on the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe diameter and length, the number and type of fittings and accessories</span></div>
<div style="text-align: left;">
<span style="font-size: large;">installed in the line, and the mass flow rate, density, and viscosity of the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">As an example, the chart in Figure 10 demonstrates the impact of pressure</span></div>
<div style="text-align: left;">
<span style="font-size: large;">drop, through the suction line, on the capacity and efficiency of the system. For</span></div>
<div style="text-align: left;">
<span style="font-size: large;">this example system operating with Refrigerant-22, increasing the total</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Pressure Drop in a Suction Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period one</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Refrigerant Piping Requirements</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes </span></div>
<div style="text-align: left;">
<span style="font-size: large;">pressure drop in the suction line from 3 psi (20.7 kPa) to 6 psi (41.4 kPa)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">decreases system capacity by about 2.5 percent and decreases system</span></div>
<div style="text-align: left;">
<span style="font-size: large;">efficiency by about 2 percent.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">This reveals a compromise that the system designer must deal with. The</span></div>
<div style="text-align: left;">
<span style="font-size: large;">diameter of the suction line must be small enough that the resulting refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">velocity is sufficiently high to carry oil droplets through the pipe. However, the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe diameter must not be so small that it creates an excessive pressure drop,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">reducing system capacity too much.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The first three requirements have remained unchanged for many years.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">However, years of observation and troubleshooting has revealed that the lower</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the system refrigerant charge, the more reliably the system performs.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Therefore, a fourth requirement has been added for the design of refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">piping: minimize the total amount of refrigerant in the system. To begin with,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">this involves laying out the shortest, simplest, and most-direct pipe routing. It</span></div>
<div style="text-align: left;">
<span style="font-size: large;">also involves using the smallest pipe diameter possible, particularly for the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid line because, of the three lines, it impacts refrigerant charge the most.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The chart in Figure 11 shows that the liquid line is second only to the condenser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">in the amount of refrigerant it contains.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">This reveals another compromise for the system designer. The diameter of the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid line must be as small as possible to minimize the total refrigerant charge.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">However, the pipe diameter cannot be small enough to create an excessive</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pressure drop that results in flashing before the liquid refrigerant reaches the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">expansion device.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Minimize Refrigerant Charge</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid line suction line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condenser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">evaporator</span></div>
<div style="text-align: left;">
<span style="font-size: large;">filter</span></div>
<div style="text-align: left;">
<span style="font-size: large;">drier</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">discharge</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period one</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Refrigerant Piping Requirements</span></div>
<div style="text-align: left;">
<span style="font-size: large;">This clinic discusses the processes for sizing the interconnecting piping in an</span></div>
<div style="text-align: left;">
<span style="font-size: large;">air-conditioning system. Some of the information required for selecting the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">optimal line sizes is best known by the manufacturer. Therefore, if the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">manufacturer of the refrigeration equipment provides recommended line sizes,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">or tools for selecting the optimal line sizes, we recommend that you use those</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line sizes.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">If, however, line sizes are not provided by the manufacturer, the processes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">outlined within this clinic could be used for selecting the sizes.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Before discussing the design and installation of the suction, discharge, and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid lines, there are some general requirements that apply to all of these lines.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">First, copper tubing is typically used for refrigerant piping in air-conditioning</span></div>
<div style="text-align: left;">
<span style="font-size: large;">systems. This tubing is available in various standard diameters and wall</span></div>
<div style="text-align: left;">
<span style="font-size: large;">thicknesses. The nominal diameter of the tubing is expressed in terms of its</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Involve the Manufacturer</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ If provided, use refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line sizes recommended by</span></div>
<div style="text-align: left;">
<span style="font-size: large;">manufacturer</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 12</span></div>
<div style="text-align: left;">
<span style="font-size: large;">General Piping Requirements</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Use clean Type L copper tubing</span></div>
<div style="text-align: left;">
<span style="font-size: large;">◆ Copper-to-copper joints: BCuP-6 without flux</span></div>
<div style="text-align: left;">
<span style="font-size: large;">◆ Copper-to-steel (or brass) joints: BAg-28, non-acid flux</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Properly support piping to account for</span></div>
<div style="text-align: left;">
<span style="font-size: large;">expansion, vibration, and weight</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Avoid installing piping underground</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Test entire refrigerant circuit for leaks</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 13</span></div>
<div style="text-align: left;">
<span style="font-size: large;">TRG-TRC006-EN 9</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period one</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Refrigerant Piping Requirements</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes outside diameter. This tubing must be completely free from dirt, scale, and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">oxide. New Type L or Type ACR tubing that has been cleaned by the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">manufacturer and capped at both ends is recommended for air-conditioning</span></div>
<div style="text-align: left;">
<span style="font-size: large;">applications.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The piping system is constructed by brazing copper tubes and fittings together.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">When brazing copper-to-copper joints, use BCuP-6* without flux. For copper-tosteel or copper-to-brass joints, use BAg-28* with a non-acid flux.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The refrigerant piping must be properly supported to account for expansion,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">vibration, and the total weight of the piping. When a pipe experiences a</span></div>
<div style="text-align: left;">
<span style="font-size: large;">temperature change, it is subject to a certain amount of expansion and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">contraction. Because the refrigerant piping is connected to the compressor,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">vibration forces are transmitted to the piping itself. Finally, the weight of the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant-filled pipe and fittings must be supported to prevent the pipes from</span></div>
<div style="text-align: left;">
<span style="font-size: large;">sagging, bending, or breaking.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Avoid installing refrigerant piping underground. It is very difficult to maintain</span></div>
<div style="text-align: left;">
<span style="font-size: large;">cleanliness during installation or to test for leaks. If underground installation is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">unavoidable, each line must be insulated separately, and then the lines must be</span></div>
<div style="text-align: left;">
<span style="font-size: large;">waterproofed and protected with a hard casing (such as PVC).</span></div>
<div style="text-align: left;">
<span style="font-size: large;">After the piping has been installed, the entire refrigeration circuit must be</span></div>
<div style="text-align: left;">
<span style="font-size: large;">tested for leaks before it can be charged with refrigerant. This process typically</span></div>
<div style="text-align: left;">
<span style="font-size: large;">involves pressurizing the entire piping system with dry nitrogen to examine</span></div>
<div style="text-align: left;">
<span style="font-size: large;">each brazed joint for leaks.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Each of these issues is discussed in greater detail in the Trane Reciprocating</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Refrigeration Manual.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">* Based on the American Welding Society’s (AWS) Specification for Filler</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Metals for Brazing and Braze Welding, publication A5.8–1992</span></div>
<div style="text-align: left;">
<span style="font-size: large;">10 TRG-TRC006-EN</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period two</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Suction Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The first line to be considered is the suction line. Again, this pipe conducts lowpressure refrigerant vapor from the evaporator to the compressor.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Requirements for Sizing and Routing</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The diameter of the suction line must be small enough that the resulting</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant velocity is sufficiently high to carry oil droplets, at all steps of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor unloading. If the velocity in the pipe is too high, however,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">objectionable noise may result. Also, the pipe diameter should be as large as</span></div>
<div style="text-align: left;">
<span style="font-size: large;">possible to minimize pressure drop and thereby maximize system capacity and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">efficiency.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period two</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Suction Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Refrigerant Piping</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 14</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Requirements for Sizing and Routing</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Ensure adequate velocity to return oil to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor at all steps of unloading</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Avoid excessive noise</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Minimize system capacity and efficiency loss</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 15</span></div>
<div style="text-align: left;">
<span style="font-size: large;">TRG-TRC006-EN 11</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period two</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Suction Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">It may be helpful to compare the old “rules” for selecting the diameter of the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction line with the newer rules that result from changes in compressor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">technology, recent research, and the additional requirement to minimize</span></div>
<div style="text-align: left;">
<span style="font-size: large;">system refrigerant charge.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">In the past, many suction lines for systems operating with Refrigerant-22 were</span></div>
<div style="text-align: left;">
<span style="font-size: large;">sized to ensure that the minimum velocity in a vertical suction riser was more</span></div>
<div style="text-align: left;">
<span style="font-size: large;">than 1,000 fpm (5 m/s), and the minimum velocity in a horizontal section was</span></div>
<div style="text-align: left;">
<span style="font-size: large;">more than 500 fpm (2.5 m/s). Actually, the minimum allowable velocity in a</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction riser depends on the diameter of the pipe.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The minimum velocity required to carry oil droplets up a vertical riser is higher</span></div>
<div style="text-align: left;">
<span style="font-size: large;">for a larger diameter pipe than it is for a smaller diameter pipe. This is due to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the velocity profile of the refrigerant flowing inside the pipe. In a smaller</span></div>
<div style="text-align: left;">
<span style="font-size: large;">diameter pipe, the higher-velocity refrigerant is closer to the inner walls of the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe than it is in a larger-diameter pipe. For instance, while the minimum</span></div>
<div style="text-align: left;">
<span style="font-size: large;">allowable velocity in a 2 1/8 in. (54 mm)-diameter suction riser is approximately</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1,000 fpm (5 m/s), the minimum velocity in a 1 1/8 in. (28 mm)-diameter riser is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">only 700 fpm (3.6 m/s). While the old minimum-velocity limits were easy to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">remember, they may lead to the unnecessary use of double suction risers.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The recommended maximum-velocity limit of 4,000 fpm (20 m/s) has not</span></div>
<div style="text-align: left;">
<span style="font-size: large;">changed. A higher velocity inside the suction line may cause objectionable</span></div>
<div style="text-align: left;">
<span style="font-size: large;">noise for those nearby.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Another common rule, in a system operating with R-22, was to limit the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pressure drop through the suction line to 3 psi (20 kPa). Although this was often</span></div>
<div style="text-align: left;">
<span style="font-size: large;">thought to be a maximum limit, this value was originally intended to be only a</span></div>
<div style="text-align: left;">
<span style="font-size: large;">recommendation, or guideline, for minimizing capacity and efficiency loss.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Today, architects and HVAC system design engineers are placing the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">components of the refrigeration system farther apart, and this 3 psi (20 kPa)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">limit is often overly restrictive. Longer line lengths and the associated higher</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pressure drop can be tolerated, assuming that the loss of system capacity and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">efficiency is acceptable for the given application. Of course, it is still good</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Sizing “Rules”</span></div>
<div style="text-align: left;">
<span style="font-size: large;">minimum velocity</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1,000 fpm (5 m/s) based on diameter of riser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">for vertical risers</span></div>
<div style="text-align: left;">
<span style="font-size: large;">500 fpm (2.5 m/s) percentage of minimum</span></div>
<div style="text-align: left;">
<span style="font-size: large;">for horizontal sections riser velocity</span></div>
<div style="text-align: left;">
<span style="font-size: large;">maximum velocity</span></div>
<div style="text-align: left;">
<span style="font-size: large;">4,000 fpm (20 m/s) 4,000 fpm (20 m/s)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">maximum pressure drop</span></div>
<div style="text-align: left;">
<span style="font-size: large;">3 psi (20 kPa) based on specific system</span></div>
<div style="text-align: left;">
<span style="font-size: large;">requirements</span></div>
<div style="text-align: left;">
<span style="font-size: large;">old rules for R-22 new rules for R-22</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 16</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period two</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Suction Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">practice to minimize pressure drop, but an arbitrary limit places an unnecessary</span></div>
<div style="text-align: left;">
<span style="font-size: large;">restriction on the system designer.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Sizing Process</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Following are the steps to follow when selecting the proper diameter of the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction line:</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1) Determine the total length of suction-line piping.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">2) Calculate the refrigerant velocity at both maximum and minimum system</span></div>
<div style="text-align: left;">
<span style="font-size: large;">capacities.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">3) Select the largest pipe diameter that will result in acceptable refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">velocity at both maximum and minimum capacities.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">4) Calculate the total “equivalent” length of piping by adding the actual length</span></div>
<div style="text-align: left;">
<span style="font-size: large;">of straight pipe to the equivalent length of any fittings to be installed in the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction line.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">5) Determine the pressure drop (based on the total equivalent length) due to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the straight pipe and fittings.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">6) Add the pressure drop due to any accessories installed in the suction line.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">To begin with, the refrigerant piping should be routed in the shortest and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">simplest manner possible, minimizing the total length of piping. From the initial</span></div>
<div style="text-align: left;">
<span style="font-size: large;">layout, the total measured length of the suction line can be estimated.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Process for Sizing</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1 Determine total length of piping</span></div>
<div style="text-align: left;">
<span style="font-size: large;">2 Calculate refrigerant velocity at maximum and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">minimum capacities</span></div>
<div style="text-align: left;">
<span style="font-size: large;">3 Select largest pipe diameter that results in</span></div>
<div style="text-align: left;">
<span style="font-size: large;">acceptable velocity at both maximum and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">minimum capacities</span></div>
<div style="text-align: left;">
<span style="font-size: large;">4 Calculate total equivalent length of straight pipe</span></div>
<div style="text-align: left;">
<span style="font-size: large;">and fittings</span></div>
<div style="text-align: left;">
<span style="font-size: large;">5 Determine pressure drop due to pipe and fittings</span></div>
<div style="text-align: left;">
<span style="font-size: large;">6 Add pressure drop due to accessories</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period two</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Suction Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">If the system contains more than one independent refrigerant circuit, each</span></div>
<div style="text-align: left;">
<span style="font-size: large;">circuit requires its own set of refrigerant lines. Therefore, the capacity of each</span></div>
<div style="text-align: left;">
<span style="font-size: large;">individual circuit must be considered separately.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Some refrigeration circuits include only one compressor that cycles on and off.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">This is very common in residential and light-commercial air-conditioning</span></div>
<div style="text-align: left;">
<span style="font-size: large;">systems. In this case, the refrigeration circuit only operates at one capacity—</span></div>
<div style="text-align: left;">
<span style="font-size: large;">fully on—so only the maximum system capacity needs to be considered.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">However, if the circuit contains a compressor that is capable of unloading, such</span></div>
<div style="text-align: left;">
<span style="font-size: large;">as a single reciprocating compressor with cylinder unloaders, or if more than</span></div>
<div style="text-align: left;">
<span style="font-size: large;">one compressor is manifolded together on a single circuit, such as multiple</span></div>
<div style="text-align: left;">
<span style="font-size: large;">scroll compressors, then the minimum capacity of the circuit must also be</span></div>
<div style="text-align: left;">
<span style="font-size: large;">determined. When the circuit unloads, less refrigerant flows through the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">system and the refrigerant velocity inside the piping is reduced.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Recall that the diameter of the suction line must provide adequate velocity at</span></div>
<div style="text-align: left;">
<span style="font-size: large;">both maximum and minimum capacities. At maximum capacity, the refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">velocity through the suction line will be the highest. Therefore, maximum</span></div>
<div style="text-align: left;">
<span style="font-size: large;">capacity is important to ensure that the refrigerant velocity is below the upper</span></div>
<div style="text-align: left;">
<span style="font-size: large;">limit of 4,000 fpm (20 m/s). At minimum capacity, the refrigerant velocity will be</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the lowest. Therefore, the minimum capacity of the refrigeration circuit is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">critical for ensuring that the refrigerant velocity is high enough to properly</span></div>
<div style="text-align: left;">
<span style="font-size: large;">return oil to the compressor.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">It is important to note that the diameter of a vertical riser does not necessarily</span></div>
<div style="text-align: left;">
<span style="font-size: large;">need to be the same as the diameter of the horizontal or vertical drop sections</span></div>
<div style="text-align: left;">
<span style="font-size: large;">of pipe. The horizontal or vertical drop sections can often be selected one</span></div>
<div style="text-align: left;">
<span style="font-size: large;">diameter larger than a vertical riser, reducing the overall pressure drop due to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the suction line. This will be demonstrated later in this period.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Unloading Refrigeration Circuits</span></div>
<div style="text-align: left;">
<span style="font-size: large;">reciprocating compressor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">with cylinder unloaders</span></div>
<div style="text-align: left;">
<span style="font-size: large;">scroll compressors</span></div>
<div style="text-align: left;">
<span style="font-size: large;">manifolded on a</span></div>
<div style="text-align: left;">
<span style="font-size: large;">single circuit</span></div>
<div style="text-align: left;">
<span style="font-size: large;"><br /></span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period two</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Suction Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The refrigerant velocity inside a pipe depends on the mass flow rate and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">density of the refrigerant, and on the inside diameter of the pipe. The chart in</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 19 shows the velocity of R-22 inside pipes of various diameters at one</span></div>
<div style="text-align: left;">
<span style="font-size: large;">particular operating condition—40°F (4.4°C) saturated suction temperature,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">125°F (51.7°C) saturated condensing temperature, 12°F (6.7°C) of superheat,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">15°F (8.3°C) of subcooling, and 70°F (38.9°C) of compressor superheat. For an</span></div>
<div style="text-align: left;">
<span style="font-size: large;">example system with an evaporator capacity of 20 tons (70.3 kW), the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant velocity inside a 2 1/8 in. (54 mm)-diameter pipe at this condition is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">about 1,850 fpm (9.4 m/s).</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The easiest and most accurate method for determining refrigerant velocity is to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">use a computer program that can calculate the velocity for various pipe sizes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">based on actual conditions. However, if you do not have access to such a</span></div>
<div style="text-align: left;">
<span style="font-size: large;">program, a chart like this may be useful.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Assume that this example 20-ton (70.3-kW) system contains one refrigeration</span></div>
<div style="text-align: left;">
<span style="font-size: large;">velocity, fpm (m/s)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">evaporator capacity, tons (kW)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">R-22</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Determine Refrigerant Velocity</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe diameter, in. (mm)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 19</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Determine Refrigerant Velocity</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe velocity, fpm (m/s)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">diameter,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">in. (mm)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">20 tons</span></div>
<div style="text-align: left;">
<span style="font-size: large;">(70.3 kW)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">10 tons</span></div>
<div style="text-align: left;">
<span style="font-size: large;">(35.2 kW)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1 1/8 (28) 7,000 (35.6) 3,500 (17.8)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1 3/8 (35) 4,600 (23.4) 2,300 (11.7)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1 5/8 (42) 3,250 (16.5) 1,625 (8.3)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">2 1/8 (54) 1,850 (9.4) 925 (4.7)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">2 5/8 (67) 1,200 (6.1) 600 (3.1)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">3 1/8 (79) 850 (4.3) 425 (2.2)</span></div>
<div style="text-align: left;">
<span style="font-size: large;"><br /></span></div>
<div style="text-align: left;">
<span style="font-size: large;">period two</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Suction Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes circuit with two steps of capacity. Maximum system (evaporator) capacity is 20 tons (70.3 kW) and the circuit can unload to 10 tons (35.2 kW) of capacity.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Using the chart in Figure 19 on page 14, the refrigerant velocity at both</span></div>
<div style="text-align: left;">
<span style="font-size: large;">maximum and minimum capacities is determined for several pipe diameters.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">After these velocities have been determined, the largest acceptable pipe</span></div>
<div style="text-align: left;">
<span style="font-size: large;">diameter is selected to minimize the overall pressure drop due to the suction</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">When this system operates at maximum capacity, use of either the 1 1/8 in.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">(28 mm)- or the 1 3/8 in. (35 mm)-diameter pipes results in a refrigerant velocity</span></div>
<div style="text-align: left;">
<span style="font-size: large;">that is greater than the recommended upper limit of 4,000 fpm (20 m/s). Again,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">these high velocities may cause objectionable noise, so these pipe sizes should</span></div>
<div style="text-align: left;">
<span style="font-size: large;">probably not be considered.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 21 shows the minimum allowable refrigerant velocity, for both a vertical</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction riser and a horizontal (or vertical drop) section of suction line, for each</span></div>
<div style="text-align: left;">
<span style="font-size: large;">standard pipe diameter. As mentioned earlier in this period, the minimum</span></div>
<div style="text-align: left;">
<span style="font-size: large;">allowable velocity in a suction riser depends on the diameter of the pipe. The</span></div>
<div style="text-align: left;">
<span style="font-size: large;">minimum velocity for a horizontal, or vertical drop, section is 75 percent of the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">minimum allowable velocity for a vertical riser of the same diameter.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The minimum velocities listed in this table assume a worst-case operating</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condition of 20°F (-6.7°C) saturated suction temperature. This provides a safety</span></div>
<div style="text-align: left;">
<span style="font-size: large;">factor, because a system will probably operate at this type of condition at some</span></div>
<div style="text-align: left;">
<span style="font-size: large;">time in its life.</span></div>
<div style="text-align: left;">
<span style="font-size: large;"><br /></span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Minimum Allowable Velocities</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 21</span></div>
<div style="text-align: left;">
<span style="font-size: large;">16 TRG-TRC006-EN</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period two</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Suction Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Based on the minimum allowable velocities listed in Figure 21 on page 15, a</span></div>
<div style="text-align: left;">
<span style="font-size: large;">2 1/8 in. (54 mm) pipe will result in acceptable velocity, at both maximum and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">minimum capacities, for the horizontal and vertical drop sections of this</span></div>
<div style="text-align: left;">
<span style="font-size: large;">example suction line. One size larger would result in a velocity that is too low</span></div>
<div style="text-align: left;">
<span style="font-size: large;">when the system operates at minimum capacity.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">When the circuit unloads to 10 tons (35.2 kW), however, the velocity inside a</span></div>
<div style="text-align: left;">
<span style="font-size: large;">2 1/8 in. (54 mm) pipe—925 fpm (4.7 m/s)—will drop below the minimum</span></div>
<div style="text-align: left;">
<span style="font-size: large;">allowable velocity for a vertical riser of this diameter—980 fpm (5.0 m/s).</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Downsizing all vertical suction risers to 1 5/8 in. (42 mm)-diameter pipe will</span></div>
<div style="text-align: left;">
<span style="font-size: large;">result in acceptable velocity at both maximum and minimum capacities. At</span></div>
<div style="text-align: left;">
<span style="font-size: large;">minimum capacity, the velocity—1,625 fpm (8.3 m/s)—is above the minimum</span></div>
<div style="text-align: left;">
<span style="font-size: large;">allowable velocity for a riser of this diameter—840 fpm (4.3 m/s). At maximum</span></div>
<div style="text-align: left;">
<span style="font-size: large;">capacity, the velocity—3,250 fpm (16.5 m/s)—is below the 4,000 fpm (20 m/s)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">upper limit.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Select Suction Line Size</span></div>
<div style="text-align: left;">
<span style="font-size: large;">riser horiz/drop</span></div>
<div style="text-align: left;">
<span style="font-size: large;">20 (70.3) 1,850 (9.4)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">10 (35.2) 925 (4.7)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">circuit</span></div>
<div style="text-align: left;">
<span style="font-size: large;">capacity,<span class="Apple-tab-span" style="white-space: pre;"> </span>minimum velocity for 2 1/8 in.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">(54 mm) pipe, fpm (m/s)<span class="Apple-tab-span" style="white-space: pre;"> </span>velocity inside</span></div>
<div style="text-align: left;">
<span style="font-size: large;">2 1/8 in. (54 mm)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">tons (kW)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe, fpm (m/s)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">980 (5.0) 735 (3.7)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">riser horiz/drop</span></div>
<div style="text-align: left;">
<span style="font-size: large;">20 (70.3) 3,250 (16.5)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">10 (35.2) 1,625 (8.3)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">circuit</span></div>
<div style="text-align: left;">
<span style="font-size: large;">capacity,<span class="Apple-tab-span" style="white-space: pre;"> </span>minimum velocity for 1 5/8 in.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">(42 mm) pipe, fpm (m/s)<span class="Apple-tab-span" style="white-space: pre;"> </span>velocity inside</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1 5/8 in. (42 mm)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">tons (kW)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe, fpm (m/s)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">840 (4.3) 630 (3.2)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 22</span></div>
<div style="text-align: left;">
<span style="font-size: large;">TRG-TRC006-EN 17</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period two</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Suction Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">For this example system, a 2 1/8 in. (54 mm)-diameter pipe can be used for the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">horizontal and vertical drop sections of the suction line, and a 1 5/8 in. (42 mm)-</span></div>
<div style="text-align: left;">
<span style="font-size: large;">diameter pipe should be used for the vertical riser. This combination of pipe</span></div>
<div style="text-align: left;">
<span style="font-size: large;">sizes will ensure proper oil movement at both maximum and minimum system</span></div>
<div style="text-align: left;">
<span style="font-size: large;">capacities, and minimize the overall pressure drop due to the suction line.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">This process suggests selecting the largest-possible pipe diameter to minimize</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pressure drop. For some applications, however, using a smaller pipe diameter</span></div>
<div style="text-align: left;">
<span style="font-size: large;">may be possible and can reduce the installed cost of the system. Of course, the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">smaller pipe diameter will result in a higher pressure drop and must meet the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">minimum and maximum velocity requirements.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">For this example system, for the vertical riser, a single pipe diameter was</span></div>
<div style="text-align: left;">
<span style="font-size: large;">selected that provides adequate velocity at minimum capacity without</span></div>
<div style="text-align: left;">
<span style="font-size: large;">exceeding the upper velocity limit at maximum capacity. This is generally</span></div>
<div style="text-align: left;">
<span style="font-size: large;">possible when the minimum capacity of the refrigeration circuit is not less than</span></div>
<div style="text-align: left;">
<span style="font-size: large;">30 to 37 percent of maximum capacity.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Selected Suction Line Sizes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">evaporator</span></div>
<div style="text-align: left;">
<span style="font-size: large;">2 1/8 in.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">(54 mm)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1 5/8 in. (42 mm)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">riser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">2 1/8 in.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">(54 mm)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">drop</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 23</span></div>
<div style="text-align: left;">
<span style="font-size: large;">18 TRG-TRC006-EN</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period two</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Suction Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">If the refrigeration circuit unloads to less than 30 to 37 percent of maximum</span></div>
<div style="text-align: left;">
<span style="font-size: large;">capacity, a double suction riser may be required.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Using the same example 20-ton (70.3-kW) system, assume that the refrigeration</span></div>
<div style="text-align: left;">
<span style="font-size: large;">circuit can, instead, unload to 5 tons (17.6 kW). At this minimum capacity, the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">velocity inside the 1 5/8 in. (42 mm) pipe—810 fpm (4.1 m/s)—will drop below</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the minimum allowable velocity for a riser of this diameter—840 fpm (4.3 m/s).</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Selecting the smaller 1 3/8 in. (35 mm)-diameter pipe for the vertical riser would</span></div>
<div style="text-align: left;">
<span style="font-size: large;">result in a velocity that is too high—4,600 fpm (23.4 m/s)—at maximum</span></div>
<div style="text-align: left;">
<span style="font-size: large;">capacity.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">A double suction riser is constructed of a larger-diameter riser with a trap at the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">base and a smaller-diameter riser in parallel. At maximum capacity, the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant vapor flows up both risers at velocities that are adequate to carry the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">oil droplets.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Double Suction Riser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">20 (70.3) 3,250 (16.5)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">5 (17.6) 810 (4.1)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">circuit</span></div>
<div style="text-align: left;">
<span style="font-size: large;">capacity,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">tons (kW)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">minimum velocity for</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1 5/8 in. (42 mm) riser,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">fpm (m/s)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">velocity inside</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1 5/8 in. (42 mm)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe, fpm (m/s)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">840 (4.3)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">20 (70.3) 4,600 (23.4)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">5 (17.6) 1,150 (5.9)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">circuit</span></div>
<div style="text-align: left;">
<span style="font-size: large;">capacity,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">tons (kW)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">minimum velocity for</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1 3/8 in. (35 mm) riser,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">fpm (m/s)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">velocity inside</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1 3/8 in. (35 mm)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe, fpm (m/s)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">780 (4.0)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 24</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Double Suction Riser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">larger</span></div>
<div style="text-align: left;">
<span style="font-size: large;">riser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">smaller</span></div>
<div style="text-align: left;">
<span style="font-size: large;">riser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">trap</span></div>
<div style="text-align: left;">
<span style="font-size: large;"><br /></span></div>
<div style="text-align: left;">
<span style="font-size: large;">period two</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Suction Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes At minimum capacity, the refrigerant velocity in the two risers becomes too low</span></div>
<div style="text-align: left;">
<span style="font-size: large;">to carry the oil droplets. The oil from both risers therefore drains down, filling</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the trap at the base of the larger riser. When this trap becomes completely filled</span></div>
<div style="text-align: left;">
<span style="font-size: large;">with oil, it prevents refrigerant vapor from flowing up the larger riser, and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">diverts all the refrigerant up the smaller riser. This smaller riser is constructed</span></div>
<div style="text-align: left;">
<span style="font-size: large;">of a pipe with a diameter that is small enough to maintain adequate velocity at</span></div>
<div style="text-align: left;">
<span style="font-size: large;">minimum capacity. When system capacity is increased again, the higher</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant velocity clears the trap of oil, and refrigerant vapor again flows up</span></div>
<div style="text-align: left;">
<span style="font-size: large;">both risers.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Notice the inverted trap at the top of the larger riser. When the trap at the base</span></div>
<div style="text-align: left;">
<span style="font-size: large;">of the larger riser is filled with oil, and refrigerant flows up only the smaller</span></div>
<div style="text-align: left;">
<span style="font-size: large;">riser, this inverted trap prevents oil from draining back into the larger riser. This</span></div>
<div style="text-align: left;">
<span style="font-size: large;">configuration minimizes the amount of oil trapped in the double riser under this</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condition, therefore maximizing the amount of oil that is returned to the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">When sizing a double suction riser, the diameter of the smaller riser should be</span></div>
<div style="text-align: left;">
<span style="font-size: large;">selected to provide the minimum allowable velocity at minimum capacity. The</span></div>
<div style="text-align: left;">
<span style="font-size: large;">diameter of the larger riser should then be selected so that, at maximum</span></div>
<div style="text-align: left;">
<span style="font-size: large;">capacity, the velocities in both risers are greater than the minimum allowable</span></div>
<div style="text-align: left;">
<span style="font-size: large;">velocity and less than 4,000 fpm (20 m/s).</span></div>
<div style="text-align: left;">
<span style="font-size: large;">For this example system, the diameter of the smaller riser is 1 3/8 in. (35 mm).</span></div>
<div style="text-align: left;">
<span style="font-size: large;">When the system operates at its minimum capacity of 5 tons (17.6 kW), the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">velocity inside the 1 3/8 in. (35 mm) riser—1,150 fpm (5.8 m/s)—is above the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">minimum allowable velocity for a riser of this diameter.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">At the maximum system capacity of 20 tons (70.3 kW), the smaller riser is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">assumed to handle the same 5 tons (17.6 kW) of capacity, and the larger riser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">must handle the remaining capacity. At 15 tons (52.8 kW) of capacity, the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant velocity in a 1 5/8 in. (42 mm) riser—2,450 fpm (12.4 m/s)—is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">between the maximum and minimum allowable velocities for a riser of this</span></div>
<div style="text-align: left;">
<span style="font-size: large;">diameter.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Sizing a Double Suction Riser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Sizing the smaller riser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Sizing the larger riser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">5 (17.6) 1,150 (5.8)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">circuit</span></div>
<div style="text-align: left;">
<span style="font-size: large;">capacity,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">tons (kW)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">minimum velocity</span></div>
<div style="text-align: left;">
<span style="font-size: large;">for 1 3/8 in. (35 mm)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">riser, fpm (m/s)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">velocity inside</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1 3/8 in. (35 mm)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe, fpm (m/s)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">780 (4.0)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">15 (52.8) 2,450 (12.4)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">circuit</span></div>
<div style="text-align: left;">
<span style="font-size: large;">capacity,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">tons (kW)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">minimum velocity</span></div>
<div style="text-align: left;">
<span style="font-size: large;">for 1 5/8 in. (42 mm)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">riser, fpm (m/s)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">velocity inside</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1 5/8 in. (42 mm)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe, fpm (m/s)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">840 (4.3)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period two</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Suction Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">For this example system, a 2 1/8 in. (54 mm)-diameter pipe can be used for the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">horizontal or vertical drop sections, and the double suction riser should be</span></div>
<div style="text-align: left;">
<span style="font-size: large;">constructed using 1 5/8 in. (42 mm)-diameter pipe for the larger riser and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1 3/8 in. (35 mm)-diameter pipe for the smaller riser.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Do not use a double suction riser unless it is absolutely necessary! The double</span></div>
<div style="text-align: left;">
<span style="font-size: large;">riser stores a large amount of oil—oil that is preferably left in the crankcase of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the compressor. If a double riser is required, check with the equipment</span></div>
<div style="text-align: left;">
<span style="font-size: large;">manufacturer to determine if more oil must be added to the system.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">After the pipe diameters are selected, the overall pressure drop due to the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction line can be calculated. The next step is to calculate the total</span></div>
<div style="text-align: left;">
<span style="font-size: large;">“equivalent” length of the suction line. The total equivalent length is the actual</span></div>
<div style="text-align: left;">
<span style="font-size: large;">measured length of straight pipe plus the pressure drop through any fittings,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">such as elbows and tees. The pressure drop through the fittings is expressed in</span></div>
<div style="text-align: left;">
<span style="font-size: large;">terms of the length of straight pipe that would produce the same pressure drop.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">To determine the equivalent length of various copper fittings, Trane now uses</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the results from two decades of research conducted for the American Society of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Mechanical Engineers (ASME). This research produced a method for predicting</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the pressure drop, in terms of equivalent length (Leq), through various types of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">copper fittings by using the radius of curvature (r) of the fitting divided by its</span></div>
<div style="text-align: left;">
<span style="font-size: large;">diameter (d), or r/d. Table 1 on page 21 includes this data.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Calculate Total Equivalent Length</span></div>
<div style="text-align: left;">
<span style="font-size: large;">L</span></div>
<div style="text-align: left;">
<span style="font-size: large;">eq is based on r/d</span></div>
<div style="text-align: left;">
<span style="font-size: large;">radius of curvature (r)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">diameter (d)</span></div>
<div style="text-align: left;">
<span style="font-size: large;"><br /></span></div>
<div style="text-align: left;">
<span style="font-size: large;">period two</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Suction Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The research findings show that the equivalent lengths of copper fittings are</span></div>
<div style="text-align: left;">
<span style="font-size: large;">much smaller than the data used in the past. The table in Figure 28 compares</span></div>
<div style="text-align: left;">
<span style="font-size: large;">some of the equivalent-length data from this research to the values commonly</span></div>
<div style="text-align: left;">
<span style="font-size: large;">used in the past. While this data is for long-radius elbows, the same method is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">used to predict the equivalent length of short-radius elbows and tees.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The suction line for this example 20-ton (70.3-kW) system, shown in Figure 23</span></div>
<div style="text-align: left;">
<span style="font-size: large;">on page 17, is 70 ft (21.4 m) long. The horizontal and vertical drop sections total</span></div>
<div style="text-align: left;">
<span style="font-size: large;">55 ft (16.8 m) in length, and are constructed of 2 1/8 in. (54 mm)-diameter pipe</span></div>
<div style="text-align: left;">
<span style="font-size: large;">with three long-radius elbows and three short-radius elbows. The single vertical</span></div>
<div style="text-align: left;">
<span style="font-size: large;">riser is 15 ft (4.6 m) long, and is constructed of 1 5/8 in. (42 mm)-diameter pipe</span></div>
<div style="text-align: left;">
<span style="font-size: large;">with no fittings.</span></div>
<div style="text-align: left;">
<span style="font-size: large;"><br /></span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Determine Pressure Drop</span></div>
<div style="text-align: left;">
<span style="font-size: large;"><br /></span></div>
<div style="text-align: left;">
<span style="font-size: large;">p2 1/8 in. = = 66.1 ft 1.4 psi/100 ft 0.93 psi</span></div>
<div style="text-align: left;">
<span style="font-size: large;">p54 mm = = 20.2 m 3.2 kPa/10 m 6.4 kPa</span></div>
<div style="text-align: left;">
<span style="font-size: large;">p1 5/8 in. = = 15 ft 6 psi/100 ft 0.9 psi</span></div>
<div style="text-align: left;">
<span style="font-size: large;">p42 mm = = 4.6 m 13.5 kPa/10 m 6.2 kPa</span></div>
<div style="text-align: left;">
<span style="font-size: large;"><br /></span></div>
<div style="text-align: left;">
<span style="font-size: large;">period two</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Suction Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes Therefore, the total pressure drop through the straight pipe and fittings for this example suction line is 1.83 psi (12.6 kPa).</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The final step toward calculating the total pressure drop is to add the pressure</span></div>
<div style="text-align: left;">
<span style="font-size: large;">drop due to any accessories that are to be installed in the suction line. The most</span></div>
<div style="text-align: left;">
<span style="font-size: large;">common accessories installed in a suction line are a suction filter and manual</span></div>
<div style="text-align: left;">
<span style="font-size: large;">ball valves that can be used to isolate this filter when it needs to be replaced.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Assuming that this example system includes one suction filter and two manual</span></div>
<div style="text-align: left;">
<span style="font-size: large;">ball valves installed in the 2 1/8 in. (54 mm) line, the total pressure drop due to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the suction line is 3.86 psi (26.6 kPa).</span></div>
<div style="text-align: left;">
<span style="font-size: large;">As mentioned earlier, a common rule in the past was to limit the pressure drop</span></div>
<div style="text-align: left;">
<span style="font-size: large;">through the suction line to 3 psi (20 kPa) for a system operating with R-22.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">However, long line lengths, and the associated higher pressure drops, can be</span></div>
<div style="text-align: left;">
<span style="font-size: large;">tolerated assuming that the impact on system capacity and efficiency is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">acceptable for the given application.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">∆p = = 0.93 psi 0.9 psi + 1.83 psi</span></div>
<div style="text-align: left;">
<span style="font-size: large;">∆p = = 6.4 kPa 6.2 kPa + 12.6 kPa</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Add Pressure Drop of Accessories</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Suction filter = 2 psi (13.8 kPa)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Angle valve = 1 psi (6.9 kPa)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Ball valve = 1 equivalent ft (0.3 m)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction line filter</span></div>
<div style="text-align: left;">
<span style="font-size: large;">p 1.83 psi 2 psi 2 1 ft = = + + 1.4 psi/10 ft 3.86 psi</span></div>
<div style="text-align: left;">
<span style="font-size: large;">p 12.6 kPa 13.8 kPa 2 0.3 m = = + + 3.2 kPa/10 m 26.6 kPa</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period two</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Suction Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Other Considerations</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Certain precautions should be taken when routing the suction line. First, proper</span></div>
<div style="text-align: left;">
<span style="font-size: large;">location and attachment of the remote expansion-valve bulb is very</span></div>
<div style="text-align: left;">
<span style="font-size: large;">important. This remote bulb, which measures the temperature of the refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">leaving the evaporator, should be firmly attached to a straight, well-drained,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">horizontal section of the suction line. The external equalizer line should be</span></div>
<div style="text-align: left;">
<span style="font-size: large;">inserted downstream of the remote bulb, in order to prevent influencing the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">temperature measured by the bulb due to any leakage of liquid refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">through the equalizer line.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The section of pipe at the outlet of the evaporator must be long enough to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">permit the attachment of the remote bulb and the insertion of the external</span></div>
<div style="text-align: left;">
<span style="font-size: large;">equalizer line. A good rule is to allow 12 in. (300 mm) of straight horizontal pipe</span></div>
<div style="text-align: left;">
<span style="font-size: large;">for these two connections. Under no circumstances should the remote bulb be</span></div>
<div style="text-align: left;">
<span style="font-size: large;">located on a section of pipe where oil or liquid refrigerant could be trapped. The</span></div>
<div style="text-align: left;">
<span style="font-size: large;">presence of oil or liquid refrigerant can cause false temperature readings.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Slightly pitch this short horizontal section of pipe downward from the suction</span></div>
<div style="text-align: left;">
<span style="font-size: large;">header—1 in./10 ft (10 mm/3 m) in the direction of flow. For best temperature</span></div>
<div style="text-align: left;">
<span style="font-size: large;">sensing, the remote bulb should be firmly attached to the top of this section of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe and well insulated.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">In addition, an access port should be located near the external equalizer line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">connection. This port provides a point for accurate pressure measurement</span></div>
<div style="text-align: left;">
<span style="font-size: large;">when checking or adjusting the superheat setting of the TXV.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">TXV Installation</span></div>
<div style="text-align: left;">
<span style="font-size: large;">external equalizer line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">remote</span></div>
<div style="text-align: left;">
<span style="font-size: large;">bulb</span></div>
<div style="text-align: left;">
<span style="font-size: large;">evaporator</span></div>
<div style="text-align: left;">
<span style="font-size: large;">TXV</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">vapor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">distributor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;"><br /></span></div>
<div style="text-align: left;">
<span style="font-size: large;">period two</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Suction Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">After this short horizontal section, the suction line should drop vertically</span></div>
<div style="text-align: left;">
<span style="font-size: large;">downward to allow the evaporator, and the section of pipe with the TXV bulb</span></div>
<div style="text-align: left;">
<span style="font-size: large;">attached, to drain freely when the system is operating.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">If the suction line leaves the evaporator and then must rise immediately, this</span></div>
<div style="text-align: left;">
<span style="font-size: large;">can be accomplished by using a small trap at the end of the horizontal section</span></div>
<div style="text-align: left;">
<span style="font-size: large;">of pipe, just before the suction line rises. The purpose of this trap is to provide</span></div>
<div style="text-align: left;">
<span style="font-size: large;">free drainage from the evaporator and the section of pipe to which the TXV</span></div>
<div style="text-align: left;">
<span style="font-size: large;">bulb is attached. This ensures that the TXV bulb is not the “low spot” in the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">piping where oil or liquid refrigerant could be trapped. The purpose of this trap</span></div>
<div style="text-align: left;">
<span style="font-size: large;">is not to drain the suction riser.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The suction line must then rise above the height of the evaporator coil. This</span></div>
<div style="text-align: left;">
<span style="font-size: large;">prevents refrigerant and oil inside the evaporator from free draining into the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction line, and toward the compressor, when the system is off.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The configuration in Figure 32 is typical for a system with an indoor air handler,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">where the refrigerant piping is routed along the ceiling and must drop down to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the evaporator.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">single distributor on circuit</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Evaporator Coil Connection</span></div>
<div style="text-align: left;">
<span style="font-size: large;">TXV</span></div>
<div style="text-align: left;">
<span style="font-size: large;">bulb</span></div>
<div style="text-align: left;">
<span style="font-size: large;">must rise above</span></div>
<div style="text-align: left;">
<span style="font-size: large;">height of evaporator</span></div>
<div style="text-align: left;">
<span style="font-size: large;">must drop below</span></div>
<div style="text-align: left;">
<span style="font-size: large;">header outlet</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction header</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 32</span></div>
<div style="text-align: left;">
<span style="font-size: large;">26 TRG-TRC006-EN</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period two</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Suction Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">If the suction line leaves the evaporator and then must drop vertically, an</span></div>
<div style="text-align: left;">
<span style="font-size: large;">inverted trap is used to prevent refrigerant and oil inside the evaporator from</span></div>
<div style="text-align: left;">
<span style="font-size: large;">free draining into the suction line, and toward the compressor, when the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">system is off.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">This involves piping the suction line to rise above the height of the evaporator</span></div>
<div style="text-align: left;">
<span style="font-size: large;">coil, installing an inverted trap, and then allowing the line to drop back down</span></div>
<div style="text-align: left;">
<span style="font-size: large;">below the evaporator.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">When an evaporator has more than one distributor connected to a single</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigeration circuit, there are some additional considerations for manifolding</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the suction headers into a single suction line.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">First, arrange the suction line so that the refrigerant vapor leaving the top</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction header flows downward, connecting to the pipes leaving the other</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction headers. This manifold pipe should drop below the lowest suction</span></div>
<div style="text-align: left;">
<span style="font-size: large;">single distributor on circuit</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Evaporator Coil Connection</span></div>
<div style="text-align: left;">
<span style="font-size: large;">TXV</span></div>
<div style="text-align: left;">
<span style="font-size: large;">bulb</span></div>
<div style="text-align: left;">
<span style="font-size: large;">must rise above</span></div>
<div style="text-align: left;">
<span style="font-size: large;">height of evaporator</span></div>
<div style="text-align: left;">
<span style="font-size: large;">must drop below</span></div>
<div style="text-align: left;">
<span style="font-size: large;">header outlet</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction header</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 33</span></div>
<div style="text-align: left;">
<span style="font-size: large;">multiple distributors on circuit</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Evaporator Coil Connections</span></div>
<div style="text-align: left;">
<span style="font-size: large;">TXV</span></div>
<div style="text-align: left;">
<span style="font-size: large;">bulb</span></div>
<div style="text-align: left;">
<span style="font-size: large;">must drop below</span></div>
<div style="text-align: left;">
<span style="font-size: large;">lowest header outlet double-elbow</span></div>
<div style="text-align: left;">
<span style="font-size: large;">configuration</span></div>
<div style="text-align: left;">
<span style="font-size: large;">must rise above</span></div>
<div style="text-align: left;">
<span style="font-size: large;">height of evaporator</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 34</span></div>
<div style="text-align: left;">
<span style="font-size: large;">TRG-TRC006-EN 27</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period two</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Suction Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes header outlet before being allowed to turn upward. This allows all of the oil to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">drain out of the evaporator and congregate before it must be carried up a</span></div>
<div style="text-align: left;">
<span style="font-size: large;">vertical riser.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Second, the remote TXV bulbs and external equalizing line connections must</span></div>
<div style="text-align: left;">
<span style="font-size: large;">be located so that the conditions affecting one valve cannot influence the other</span></div>
<div style="text-align: left;">
<span style="font-size: large;">valves. The double-elbow configuration allows the corresponding section of the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">evaporator coil to drain freely while also isolating the remote bulb and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">equalizer line from the suction pressure and temperature of the above coil</span></div>
<div style="text-align: left;">
<span style="font-size: large;">sections.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The single suction line then rises above the height of the evaporator coil,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">preventing refrigerant and oil inside the evaporator from free draining into the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction line, and toward the compressor, when the system is off.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">As mentioned earlier, the trap shown in Figure 32 on page 25, and Figure 33 on</span></div>
<div style="text-align: left;">
<span style="font-size: large;">page 26, is used to provide free drainage from the evaporator and section of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe to which the TXV bulb is attached. Its purpose is not to drain the suction</span></div>
<div style="text-align: left;">
<span style="font-size: large;">riser.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">A common practice in the past was to install a trap at the base of any vertical</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction riser, and often part of the way up the riser. It was believed that these</span></div>
<div style="text-align: left;">
<span style="font-size: large;">traps would cause turbulence at the base of the riser section so that oil</span></div>
<div style="text-align: left;">
<span style="font-size: large;">accumulating in the trap would be more easily “broken up” into a mist, which</span></div>
<div style="text-align: left;">
<span style="font-size: large;">could then be carried to the top of the riser with the refrigerant vapor.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Today, we understand that oil droplets are moved inside a pipe by the force of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">mass flow, not by turbulence. It is possible to size a vertical suction riser, which</span></div>
<div style="text-align: left;">
<span style="font-size: large;">will allow the refrigerant to carry oil droplets at minimum capacity, without the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">need for a trap. If a suction riser is sized properly, oil will return to the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor regardless of whether a trap is present at the base of the riser. If a</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction riser is oversized, however, adding such a trap will not restore proper</span></div>
<div style="text-align: left;">
<span style="font-size: large;">oil movement.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Riser Traps Are Not Required</span></div>
<div style="text-align: left;">
<span style="font-size: large;"><br /></span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period two</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Suction Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Horizontal sections of the suction line should be pitched slightly—1 in./10 ft</span></div>
<div style="text-align: left;">
<span style="font-size: large;">(10 mm/3 m)—so that the refrigerant drains back toward the evaporator. This</span></div>
<div style="text-align: left;">
<span style="font-size: large;">prevents any refrigerant that condenses in the suction line from flowing into the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor when the circuit is off.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The refrigerant temperature inside the suction line is generally cooler than the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">surrounding air. Therefore, it is always good practice to insulate the entire</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction line to prevent condensation and loss of capacity due to heat gain.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Without insulation, moisture may condense on the outside surface of the pipe</span></div>
<div style="text-align: left;">
<span style="font-size: large;">and drip onto the floor or suspended ceiling below. Also, any heat gained by</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the suction line places an additional load on the system that reduces cooling</span></div>
<div style="text-align: left;">
<span style="font-size: large;">capacity, and also may result in improper motor cooling with some compressor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">designs.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The suction-line filter should be located as close as possible to the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor—its purpose is to remove foreign matter from the system and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">protect the compressor. This filter should be accompanied by manual shutoff</span></div>
<div style="text-align: left;">
<span style="font-size: large;">valves on both sides, allowing it to be isolated when the filter core needs to be</span></div>
<div style="text-align: left;">
<span style="font-size: large;">replaced.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Additionally, the suction line typically includes two access ports. One is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">installed near the compressor and is used to measure suction pressure. The</span></div>
<div style="text-align: left;">
<span style="font-size: large;">other is located near the external equalizer line connection for the TXV, and is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">used to measure superheat when checking or adjusting the TXV.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Other Considerations</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Do not use suction riser traps: they are not</span></div>
<div style="text-align: left;">
<span style="font-size: large;">required</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Pitch horizontal sections to drain toward</span></div>
<div style="text-align: left;">
<span style="font-size: large;">evaporator</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Insulate entire suction line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">◆ Prevents condensation</span></div>
<div style="text-align: left;">
<span style="font-size: large;">◆ Minimizes loss of capacity due to heat gain</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Install suction-line filter close to compressor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">◆ Manual shutoff valves allow isolation for replacement</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Install access ports to measure suction</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pressure and superheat</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period two</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Suction Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The compressor is designed to compress refrigerant vapor only. A suctionline accumulator is a device that attempts to prevent a slug of liquid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant or oil from causing damage to the compressor. The accumulator</span></div>
<div style="text-align: left;">
<span style="font-size: large;">allows liquid refrigerant and oil to separate from the refrigerant vapor, and then</span></div>
<div style="text-align: left;">
<span style="font-size: large;">be drawn into the compressor at a rate that will not cause damage.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Oversizing the accumulator, however, can cause inadequate oil return due to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">low refrigerant velocity through the accumulator. An accumulator also</span></div>
<div style="text-align: left;">
<span style="font-size: large;">increases the refrigerant charge of the system and increases the pressure drop.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Some refrigeration systems that use a flooded evaporator may require a</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction-line accumulator for freeze protection or other functions. Check with the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">equipment manufacturer to determine if a suction-line accumulator is required,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">recommended, or discouraged.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Suction-Line Accumulator</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Check with</span></div>
<div style="text-align: left;">
<span style="font-size: large;">equipment</span></div>
<div style="text-align: left;">
<span style="font-size: large;">manufacturer to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">determine if required,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">recommended, or</span></div>
<div style="text-align: left;">
<span style="font-size: large;">discouraged</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period two</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Suction Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Finally, when the system includes a reciprocating compressor, an anchored,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">45-degree canted loop should be constructed very close to the location at which</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the suction line connects to the compressor. This loop absorbs vibration</span></div>
<div style="text-align: left;">
<span style="font-size: large;">generated by the reciprocating motion of the compressor, minimizing the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">amount of vibration transmitted to the piping system.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The loop is constructed of four straight sections of pipe, each one at least ten</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe diameters in length, and four elbows. The pipe is anchored a short</span></div>
<div style="text-align: left;">
<span style="font-size: large;">distance downstream from the loop, allowing the loop to absorb vibration in</span></div>
<div style="text-align: left;">
<span style="font-size: large;">both the vertical and horizontal planes. Note that the loop is pitched downward</span></div>
<div style="text-align: left;">
<span style="font-size: large;">to provide free drainage away from the compressor.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Reciprocating Compressors</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe</span></div>
<div style="text-align: left;">
<span style="font-size: large;">anchor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pitch</span></div>
<div style="text-align: left;">
<span style="font-size: large;"><br /></span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period three</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Discharge Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The next line to be considered is the discharge line. This section of pipe</span></div>
<div style="text-align: left;">
<span style="font-size: large;">conducts hot, high-pressure refrigerant vapor from the compressor to the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condenser.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The design of the discharge line is probably less critical than that of the suction</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line because the refrigerant vapor is at a higher temperature, allowing the oil to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">be carried along more easily than in the cooler suction line. Even so, if the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">discharge line is not properly sized and installed, reliability or performance</span></div>
<div style="text-align: left;">
<span style="font-size: large;">problems can result.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Requirements for Sizing and Routing</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Similar to the suction line, the diameter of the discharge line must be small</span></div>
<div style="text-align: left;">
<span style="font-size: large;">enough that the resulting refrigerant velocity is sufficiently high to carry oil</span></div>
<div style="text-align: left;">
<span style="font-size: large;">droplets, at all steps of compressor unloading. However, if the velocity in the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe is too high, it may cause objectionable noise.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period three</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Discharge Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Refrigerant Piping</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 39</span></div>
<div style="text-align: left;">
<span style="font-size: large;">discharge line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Requirements for Sizing and Routing</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Ensure adequate velocity to return oil to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor at all steps of unloading</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Avoid excessive noise</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Minimize efficiency loss</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period three</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Discharge Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Finally, anything that causes the compressor discharge pressure to rise causes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the compressor to work harder. Therefore, the pipe diameter should be as large</span></div>
<div style="text-align: left;">
<span style="font-size: large;">as possible to minimize pressure drop and maximize compressor efficiency.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">As with the suction line, it may be helpful to compare the old “rules” for</span></div>
<div style="text-align: left;">
<span style="font-size: large;">selecting the diameter of the discharge line with the newer rules that result</span></div>
<div style="text-align: left;">
<span style="font-size: large;">from changes in compressor technology, recent research, and the additional</span></div>
<div style="text-align: left;">
<span style="font-size: large;">requirement to minimize system refrigerant charge.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">In the past, many discharge lines for systems operating with R-22 were sized</span></div>
<div style="text-align: left;">
<span style="font-size: large;">using the same minimum-velocity values that were used for sizing suction</span></div>
<div style="text-align: left;">
<span style="font-size: large;">lines. As explained in Period Two, the minimum allowable velocity at a specific</span></div>
<div style="text-align: left;">
<span style="font-size: large;">operating condition depends on the diameter of the pipe. The minimum</span></div>
<div style="text-align: left;">
<span style="font-size: large;">allowable velocity values for discharge lines are different than for suction lines,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">because the refrigerant vapor is at a higher temperature, and oil moves more</span></div>
<div style="text-align: left;">
<span style="font-size: large;">easily than in the cooler suction line.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The recommended maximum velocity limit for discharge lines is 3,500 fpm</span></div>
<div style="text-align: left;">
<span style="font-size: large;">(17.5 m/s). Again, a higher velocity inside the pipe may cause objectionable</span></div>
<div style="text-align: left;">
<span style="font-size: large;">noise.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Another “old” rule, for a system operating with R-22, was to limit the pressure</span></div>
<div style="text-align: left;">
<span style="font-size: large;">drop through the discharge line to 6 psi (41 kPa). While it is still good practice to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">minimize pressure drop, higher pressure drops can be tolerated, assuming that</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the impact on system efficiency is acceptable for the given application.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">discharge line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Sizing “Rules”</span></div>
<div style="text-align: left;">
<span style="font-size: large;">minimum velocity</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1,000 fpm (5 m/s) based on diameter of riser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">for risers</span></div>
<div style="text-align: left;">
<span style="font-size: large;">500 fpm (2.5 m/s) percentage of minimum</span></div>
<div style="text-align: left;">
<span style="font-size: large;">for horizontal sections riser velocity</span></div>
<div style="text-align: left;">
<span style="font-size: large;">maximum velocity</span></div>
<div style="text-align: left;">
<span style="font-size: large;">3,500 fpm (17.5 m/s) 3,500 fpm (17.5 m/s)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">maximum pressure drop</span></div>
<div style="text-align: left;">
<span style="font-size: large;">6 psi (41 kPa) based on specific system</span></div>
<div style="text-align: left;">
<span style="font-size: large;">requirements</span></div>
<div style="text-align: left;">
<span style="font-size: large;">old rules for R-22 new rules for R-22</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period three</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Discharge Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Sizing Process</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The steps for selecting the proper diameter of the discharge line are identical to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the steps for sizing the suction line:</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1) Determine the total length of discharge-line piping.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">2) Calculate the refrigerant velocity at both maximum and minimum system</span></div>
<div style="text-align: left;">
<span style="font-size: large;">capacities.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">3) Select the largest pipe diameter that will result in acceptable refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">velocity at both maximum and minimum capacities.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">4) Calculate the total “equivalent” length of piping by adding the actual length</span></div>
<div style="text-align: left;">
<span style="font-size: large;">of straight pipe to the equivalent length of any fittings to be installed in the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">discharge line.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">5) Determine the pressure drop (based on the total equivalent length) due to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the straight pipe and fittings.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">6) Add the pressure drop due to any accessories installed in the discharge</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Again, the total measured length of the discharge line can be estimated from</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the initial layout.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">discharge line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Process for Sizing</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1 Determine total length of piping</span></div>
<div style="text-align: left;">
<span style="font-size: large;">2 Calculate refrigerant velocity at maximum and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">minimum capacities</span></div>
<div style="text-align: left;">
<span style="font-size: large;">3 Select largest pipe diameter that results in</span></div>
<div style="text-align: left;">
<span style="font-size: large;">acceptable velocity at both maximum and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">minimum capacity</span></div>
<div style="text-align: left;">
<span style="font-size: large;">4 Calculate total equivalent length of straight pipe</span></div>
<div style="text-align: left;">
<span style="font-size: large;">and fittings</span></div>
<div style="text-align: left;">
<span style="font-size: large;">5 Determine pressure drop due to pipe and fittings</span></div>
<div style="text-align: left;">
<span style="font-size: large;">6 Add pressure drop due to accessories</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period three</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Discharge Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The chart in Figure 43 shows the velocity of R-22 inside discharge pipes of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">various diameters at one particular operating condition—40°F (4.4°C) saturated</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction temperature, 125°F (51.7°C) saturated condensing temperature, 12°F</span></div>
<div style="text-align: left;">
<span style="font-size: large;">(6.7°C) of superheat, 15°F (8.3°C) of subcooling, and 70°F (38.9°C) of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor superheat.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">For the same example 20-ton (70.3-kW) system, the refrigerant velocity inside a</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1 5/8 in. (42 mm)-diameter pipe is about 1,100 fpm (5.6 m/s) at this condition.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Again, a computer program can be used to calculate the velocity based on</span></div>
<div style="text-align: left;">
<span style="font-size: large;">actual conditions, but without a program, a chart like this may be useful.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">This example 20-ton (70.3-kW) system contains one refrigeration circuit with</span></div>
<div style="text-align: left;">
<span style="font-size: large;">two steps of capacity. Maximum capacity is 20 tons (70.3 kW) and minimum</span></div>
<div style="text-align: left;">
<span style="font-size: large;">capacity is 10 tons (35.2 kW). Using the chart in Figure 43, the refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">discharge line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Determine Refrigerant Velocity</span></div>
<div style="text-align: left;">
<span style="font-size: large;">velocity, fpm (m/s)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">evaporator capacity, tons (kW)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe diameter, in. (mm)</span></div>
<div style="text-align: left;">
<span style="font-size: large;"><br /></span></div>
<div style="text-align: left;">
<span style="font-size: large;">discharge line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Determine Refrigerant Velocity</span></div>
<div style="text-align: left;">
<span style="font-size: large;">7/8 (22) 4,050 (20.6) 2,025 (10.3)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1 1/8 (28) 2,400 (12.2) 1,200 ( 6.1)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1 3/8 (35) 1,550 ( 7.9) 775 ( 3.9)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1 5/8 (42) 1,100 ( 5.6) 550 ( 2.8)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">2 1/8 (54) 650 ( 3.3) 325 ( 1.7)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe velocity, fpm (m/s)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">diameter,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">in. (mm)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">20 tons</span></div>
<div style="text-align: left;">
<span style="font-size: large;">(70.3 kW)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">10 tons</span></div>
<div style="text-align: left;">
<span style="font-size: large;">(35.2 kW)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period three</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Discharge Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes velocity at both maximum and minimum capacities is determined for several</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe diameters.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">After these velocities have been determined, the largest acceptable pipe</span></div>
<div style="text-align: left;">
<span style="font-size: large;">diameter is selected to minimize the overall pressure drop due to the discharge</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">When this system operates at maximum capacity, use of the 7/8 in. (22 mm)-</span></div>
<div style="text-align: left;">
<span style="font-size: large;">diameter pipe results in a refrigerant velocity that is greater than the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">recommended upper limit of 3,500 fpm (17.5 m/s) for discharge lines. This high</span></div>
<div style="text-align: left;">
<span style="font-size: large;">velocity may cause objectionable noise, so this pipe size should probably not</span></div>
<div style="text-align: left;">
<span style="font-size: large;">be considered.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The table in Figure 45 shows the minimum allowable refrigerant velocity, for</span></div>
<div style="text-align: left;">
<span style="font-size: large;">both a vertical riser and a horizontal (or vertical drop) section of discharge line,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">for each standard pipe diameter. As with suction lines, the minimum velocity</span></div>
<div style="text-align: left;">
<span style="font-size: large;">for a horizontal, or vertical drop, section of discharge line is 75 percent of the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">minimum allowable velocity for a vertical riser of the same diameter.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The minimum velocities listed in this table assume a worst-case operating</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condition of 80°F (26.7°C) saturated condensing temperature.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">discharge line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Minimum Allowable Velocities</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period three</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Discharge Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Based on the minimum allowable velocities listed in Figure 45 on page 35,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1 5/8 in. (42 mm) is the largest diameter of pipe that will result in acceptable</span></div>
<div style="text-align: left;">
<span style="font-size: large;">velocity, at both maximum and minimum capacities, within horizontal and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">vertical drop sections.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">When the circuit unloads to 10 tons (35.2 kW), the velocity inside a 1 5/8 in.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">(42 mm) pipe—550 fpm (2.8 m/s)—remains above the minimum allowable</span></div>
<div style="text-align: left;">
<span style="font-size: large;">velocity for a riser of this diameter—520 fpm (2.6 m/s). One size larger (2 1/8 in.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">[54 mm]) would result in a velocity that is too low when the system operates at</span></div>
<div style="text-align: left;">
<span style="font-size: large;">minimum capacity.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">For this example system, a 1 5/8 in. (42 mm)-diameter pipe can be used for all</span></div>
<div style="text-align: left;">
<span style="font-size: large;">horizontal and vertical sections of the discharge line, including vertical risers.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">This pipe size will ensure proper oil movement at both maximum and minimum</span></div>
<div style="text-align: left;">
<span style="font-size: large;">system capacities, and minimize the overall pressure drop due to the discharge</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Select Discharge Line Size</span></div>
<div style="text-align: left;">
<span style="font-size: large;">riser horiz/drop</span></div>
<div style="text-align: left;">
<span style="font-size: large;">20 (70.3) 1,100 (5.6)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">10 (35.2) 550 (2.8)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">tons (kW)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe, fpm (m/s)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">520 (2.6) 390 (2.0)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Selected Discharge Line Size</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1 5/8 in.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">(42 mm)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condenser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1 5/8 in. (42 mm)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">riser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1 5/8 in.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">(42 mm)</span></div>
<div style="text-align: left;">
<span style="font-size: large;"><br /></span></div>
<div style="text-align: left;">
<span style="font-size: large;">period three</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Discharge Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes For this example, a single pipe diameter can be selected that provides adequate</span></div>
<div style="text-align: left;">
<span style="font-size: large;">velocity at minimum capacity, without exceeding the maximum velocity limit at</span></div>
<div style="text-align: left;">
<span style="font-size: large;">maximum capacity. If the maximum and minimum velocity requirements</span></div>
<div style="text-align: left;">
<span style="font-size: large;">cannot be achieved with a single pipe diameter, a double riser may be required.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">After the pipe diameter is selected, the overall pressure drop due to the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">discharge line can be calculated. The next step is to calculate the total</span></div>
<div style="text-align: left;">
<span style="font-size: large;">“equivalent” length of the straight pipe and fittings. The equivalent length data</span></div>
<div style="text-align: left;">
<span style="font-size: large;">for copper fittings used in the discharge line is the same as for the suction line.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The discharge line for this example 20-ton (70.3-kW) system, shown in</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 47 on page 36, is a total of 50 ft (15.2 m) long. Both the horizontal</span></div>
<div style="text-align: left;">
<span style="font-size: large;">sections and the vertical riser are constructed of 1 5/8 in. (42 mm)-diameter pipe</span></div>
<div style="text-align: left;">
<span style="font-size: large;">and contain a total of two long-radius elbows. Based on the “new” data from</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Table 1 on page 21, the equivalent length of each long-radius elbow of this</span></div>
<div style="text-align: left;">
<span style="font-size: large;">diameter is 1.0 ft (0.30 m), so the total equivalent length of the discharge line is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">52 ft (15.8 m).</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The next step is to determine the pressure drop due to the straight pipe and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">fittings, based on this calculated total equivalent length. The chart in Figure 48</span></div>
<div style="text-align: left;">
<span style="font-size: large;">shows the pressure drop, per unit of equivalent length, for different pipe</span></div>
<div style="text-align: left;">
<span style="font-size: large;">diameters and various capacities. At the maximum capacity of 20 tons</span></div>
<div style="text-align: left;">
<span style="font-size: large;">(70.3 kW), the pressure drop due to the straight, 1 5/8 in. (42 mm)-diameter pipe</span></div>
<div style="text-align: left;">
<span style="font-size: large;">and fittings is 2.1 psi per 100 ft of equivalent length (4.8 kPa/10 m), or 1.1 psi</span></div>
<div style="text-align: left;">
<span style="font-size: large;">(7.6 kPa).</span></div>
<div style="text-align: left;">
<span style="font-size: large;"><br /></span></div>
<div style="text-align: left;">
<span style="font-size: large;">discharge line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Determine Pressure Drop</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period three</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Discharge Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The final step is to add the pressure drop due to any accessories that will be</span></div>
<div style="text-align: left;">
<span style="font-size: large;">installed in the discharge line, and calculate the total pressure drop. The most</span></div>
<div style="text-align: left;">
<span style="font-size: large;">common accessories installed in a discharge line are manual ball valves that</span></div>
<div style="text-align: left;">
<span style="font-size: large;">are used to isolate portions of the system during maintenance.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Assuming that this example system includes one manual angle valve, the total</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pressure drop due to the discharge line is 2.1 psi (14.5 kPa).</span></div>
<div style="text-align: left;">
<span style="font-size: large;">As mentioned earlier, in the past, a common rule was to limit the pressure drop</span></div>
<div style="text-align: left;">
<span style="font-size: large;">through the discharge line to 6 psi (41 kPa) for a system operating with R-22.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">However, long line lengths, and the associated higher pressure drops, can be</span></div>
<div style="text-align: left;">
<span style="font-size: large;">tolerated assuming that the impact on system efficiency is acceptable for the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">given application.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">discharge line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Add Pressure Drop of Accessories</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Angle valve = 1 psi (6.9 kPa)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Ball valve = 1 equivalent ft (0.3 m)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period three</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Discharge Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Other Considerations</span></div>
<div style="text-align: left;">
<span style="font-size: large;">As with the suction line, riser traps are not required in a discharge line,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">assuming that the riser is properly sized to return oil at minimum capacity.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Horizontal sections of the discharge line should be pitched slightly—1 in./10 ft</span></div>
<div style="text-align: left;">
<span style="font-size: large;">(10 mm/3 m)—so that the refrigerant drains toward the condenser. This</span></div>
<div style="text-align: left;">
<span style="font-size: large;">prevents any refrigerant that may condense in the discharge line from flowing</span></div>
<div style="text-align: left;">
<span style="font-size: large;">back into the compressor when the system is off.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">In most cases, the discharge line does not need to be insulated. The refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">temperature inside the line is generally warmer than the surrounding air. Any</span></div>
<div style="text-align: left;">
<span style="font-size: large;">heat loss reduces the heat-rejection load of the condenser, improving system</span></div>
<div style="text-align: left;">
<span style="font-size: large;">efficiency. However, the outer surface of the discharge line can be hot. Some</span></div>
<div style="text-align: left;">
<span style="font-size: large;">sections of the discharge line may be insulated to prevent injury to someone</span></div>
<div style="text-align: left;">
<span style="font-size: large;">who may come in contact with the piping. Also, if the system has long</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant lines and is expected to operate when it is cold outdoors, the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">discharge line should be insulated to prevent refrigerant from condensing</span></div>
<div style="text-align: left;">
<span style="font-size: large;">inside the line before it reaches the condenser.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">discharge line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Other Considerations</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Do not use discharge riser traps: they are not</span></div>
<div style="text-align: left;">
<span style="font-size: large;">required</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Pitch horizontal sections to drain toward</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condenser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Insulate only to prevent accidental burns or</span></div>
<div style="text-align: left;">
<span style="font-size: large;">when system must operate in cold ambient</span></div>
<div style="text-align: left;">
<span style="font-size: large;">conditions</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period three</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Discharge Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Finally, when the system includes a reciprocating compressor, an anchored,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">45-degree canted loop should be constructed very close to the location at which</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the discharge line connects to the compressor. This loop absorbs vibration</span></div>
<div style="text-align: left;">
<span style="font-size: large;">generated by the reciprocating motion of the compressor. Note that the loop is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pitched downward to provide free drainage away from the compressor.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">discharge line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Reciprocating Compressors</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe</span></div>
<div style="text-align: left;">
<span style="font-size: large;">anchor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pitch</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period four</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Liquid Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The third line to be considered is the liquid line. This section of pipe conducts</span></div>
<div style="text-align: left;">
<span style="font-size: large;">warm, high-pressure liquid refrigerant from the condenser to the expansion</span></div>
<div style="text-align: left;">
<span style="font-size: large;">device and evaporator.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Requirements for Sizing and Routing</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The liquid line must be designed and installed to ensure that only liquid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant (no vapor) enters the expansion device. The presence of refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">vapor upstream of a TXV can result in erratic valve operation and reduced</span></div>
<div style="text-align: left;">
<span style="font-size: large;">system capacity. In order to meet this requirement, the condenser must provide</span></div>
<div style="text-align: left;">
<span style="font-size: large;">adequate subcooling, and the pressure drop through the liquid line and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">accessories must not be high enough to cause flashing upstream of the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">expansion device. Subcooling allows the liquid refrigerant to experience some</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pressure drop as it flows through the liquid line, without the risk of flashing.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period four</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Liquid Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Refrigerant Piping</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 52</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Requirements for Sizing and Routing</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Ensure that only liquid refrigerant enters</span></div>
<div style="text-align: left;">
<span style="font-size: large;">expansion device</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Minimize refrigerant charge</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Avoid excessive noise and pipe erosion</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period four</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Liquid Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Oil and liquid refrigerant mix readily, so oil movement within the liquid line is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">not a concern. However, the design of the liquid line is the most critical when it</span></div>
<div style="text-align: left;">
<span style="font-size: large;">comes to minimizing the system refrigerant charge. This is because, of the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">three lines, it has the greatest impact on the quantity of refrigerant required to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">charge the system. The diameter of the liquid line must be as small as possible</span></div>
<div style="text-align: left;">
<span style="font-size: large;">to minimize the refrigerant charge, therefore improving reliability and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">minimizing installed cost. However, if the pipe is too small, the increased</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pressure drop may cause flashing upstream of the expansion device.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The final requirement is to limit the refrigerant velocity in order to prevent</span></div>
<div style="text-align: left;">
<span style="font-size: large;">objectionable noise or erosion of the inner surfaces of the piping.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">In this example system, the refrigerant (R-22) is condensed at a temperature of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">125°F (51.7°C), which corresponds to a pressure of 293 psia (2,020 kPa). Inside</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the subcooling tubes, the temperature of the liquid refrigerant is reduced by</span></div>
<div style="text-align: left;">
<span style="font-size: large;">15°F (8.3°C) to 110°F (43.3°C). Ignoring the pressure drop due to the condenser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">and subcooler tubes, the pressure of this subcooled liquid refrigerant is the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">same, 293 psia (2,020 kPa).</span></div>
<div style="text-align: left;">
<span style="font-size: large;">At 110°F (43.3°C), the pressure of the refrigerant can be reduced to 241 psia</span></div>
<div style="text-align: left;">
<span style="font-size: large;">(1,662 kPa) before it reaches the saturated liquid condition, where flashing</span></div>
<div style="text-align: left;">
<span style="font-size: large;">occurs. In other words, the liquid refrigerant could experience a pressure drop</span></div>
<div style="text-align: left;">
<span style="font-size: large;">of up to 52 psi (358 kPa) before flashing occurs.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">In years past, the liquid line was considered an independent component of the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">system and was sized based solely on the physics of fluid flow through the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe. It was believed that increasing the diameter of the liquid line, which would</span></div>
<div style="text-align: left;">
<span style="font-size: large;">reduce the pressure drop through the piping, would increase the amount of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">subcooling remaining at the inlet of the expansion device.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The internal volume of the liquid line, however, has a significant impact on the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">ability of the condenser to provide subcooling at part-load operating</span></div>
<div style="text-align: left;">
<span style="font-size: large;">conditions. When this interaction between the liquid line and condenser is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">considered, we find that the amount of subcooling available at the expansion</span></div>
<div style="text-align: left;">
<span style="font-size: large;">device is as dependent on the ability of the condenser to provide subcooling as</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Subcooling</span></div>
<div style="text-align: left;">
<span style="font-size: large;">enthalpy, Btu/lb (kJ/kg)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period four</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Liquid Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">it is on the pressure drop due to the liquid-line piping. In fact, if the liquid line is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">too large, it will actually reduce the subcooling at the expansion device under</span></div>
<div style="text-align: left;">
<span style="font-size: large;">cooler ambient conditions.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Therefore, proper sizing of the liquid line requires an understanding of the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">entire refrigeration system, not just the liquid-line piping.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Take a look at an example 25-ton (87.9-kW) system with 150 ft (45.7 m) of liquidline piping to illustrate this point. System A uses a 7/8 in. (22 mm)-diameter</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe for the liquid line, while system B uses a larger 1 1/8 in. (28 mm)-diameter</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe. Both systems are charged so that the condenser provides 18°F (10°C) of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">subcooling at the same high outdoor temperature. Even though the rest of the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">system components are identical, system B requires 25 lb (11.3 kg) more</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant to charge the system because of the larger liquid line.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">As expected, the pressure drop due to the piping is less for system B with the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">larger diameter pipe. When the outdoor temperature is high, this reduced</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pressure drop results in more subcooling remaining at the expansion device—</span></div>
<div style="text-align: left;">
<span style="font-size: large;">14.2°F (7.9°C) compared to 12.3°F (6.8°C) for system A.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">However, one should examine what happens when the system operates at a</span></div>
<div style="text-align: left;">
<span style="font-size: large;">cooler outdoor temperature. As the outdoor temperature decreases, the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">temperature of the refrigerant inside the condenser and liquid line also</span></div>
<div style="text-align: left;">
<span style="font-size: large;">decreases. This lower temperature causes the density of the refrigerant to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">increase, requiring more mass of refrigerant in order to fill up the internal</span></div>
<div style="text-align: left;">
<span style="font-size: large;">volume of the liquid line. The result is less refrigerant remaining inside the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condenser, and therefore less subcooling provided by the condenser.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">This change in density has a more severe impact on system B with the largerdiameter liquid line, because the internal volume of the liquid line is greater. For</span></div>
<div style="text-align: left;">
<span style="font-size: large;">these two example systems, when the outdoor temperature is cooler, the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">amount of subcooling provided by the same condenser is 12.9°F (7.2°C) for</span></div>
<div style="text-align: left;">
<span style="font-size: large;">system A, but only 7.2°F (4°C) for system B.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Even though the pressure drop is still less through the larger-diameter line—</span></div>
<div style="text-align: left;">
<span style="font-size: large;">5.2°F (2.9°C) loss in subcooling due to pressure drop in system B versus 7.4°F</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Impact of Refrigerant Density Change</span></div>
<div style="text-align: left;">
<span style="font-size: large;">A 7/8 (22) high 18.0 (10) - 5.7 (3.2) = 12.3 (6.8)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">B 1 1/8 (28) high 18.0 (10) - 3.8 (2.1) = 14.2 (7.9)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">A 7/8 (22) low 12.9 (7.2) - 7.4 (4.1) = 5.5 (3.1)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">B 1 1/8 (28) low 7.2 (4.0) - 5.2 (2.9) = 2.0 (1.1)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">available subcooling, °F (°C)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">diameter,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">in. (mm)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period four</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Liquid Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">(4.1°C) in system A—the impact of the change in refrigerant density has a</span></div>
<div style="text-align: left;">
<span style="font-size: large;">greater impact on the overall system. At this cooler outdoor condition, only</span></div>
<div style="text-align: left;">
<span style="font-size: large;">2.0°F (1.1°C) of subcooling is available at the TXV in system B, while 5.5°F</span></div>
<div style="text-align: left;">
<span style="font-size: large;">(3.1°C) of subcooling is available at the TXV in system A.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Again, proper sizing of the liquid line requires an understanding of the entire</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigeration system, not just the liquid-line piping. The diameter of the liquid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line should be as small as possible, to minimize the impact of the change in</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant density. If the liquid line is too large, it may result in too little</span></div>
<div style="text-align: left;">
<span style="font-size: large;">subcooling at some part-load operating conditions.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 56 compares the old “rules” for selecting the diameter of the liquid line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">with the newer rules that result from this understanding of the impact of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant density change, recent research, and the additional requirement to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">minimize system refrigerant charge.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">In the past, many liquid lines in systems operating with R-22 were sized to limit</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the pressure drop through the piping and accessories to 6 psi (41 kPa).</span></div>
<div style="text-align: left;">
<span style="font-size: large;">However, as we just explained, limiting the pressure drop through the liquid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line does not necessarily ensure that only liquid refrigerant (no vapor) enters</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the expansion device. This rule has been rewritten to specify that adequate</span></div>
<div style="text-align: left;">
<span style="font-size: large;">subcooling must be available at the inlet of the expansion device at all</span></div>
<div style="text-align: left;">
<span style="font-size: large;">operating conditions, acknowledging this interaction between the liquid line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">and condenser. The condenser must provide adequate subcooling, and the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pressure drop through the liquid line and accessories must not be high enough</span></div>
<div style="text-align: left;">
<span style="font-size: large;">to cause flashing upstream of the expansion device. A margin of safety, such as</span></div>
<div style="text-align: left;">
<span style="font-size: large;">5°F (2.8°C), may be used to account for unexpected variations.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">In the past, the recommended maximum velocity limit for a liquid line was</span></div>
<div style="text-align: left;">
<span style="font-size: large;">360 fpm (1.8 m/s). Velocities in excess of this limit caused concern for liquidhammer effect when the flow of refrigerant was suddenly stopped, such as</span></div>
<div style="text-align: left;">
<span style="font-size: large;">when a solenoid valve closed. However, most solenoid valves used in airconditioning systems today are not quick-closing valves. That is, they do not</span></div>
<div style="text-align: left;">
<span style="font-size: large;">close rapidly enough to cause a serious hammer effect.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Sizing “Rules”</span></div>
<div style="text-align: left;">
<span style="font-size: large;">maximum pressure drop</span></div>
<div style="text-align: left;">
<span style="font-size: large;">6 psi (41 kPa) 5°F (2.8°C) subcooling</span></div>
<div style="text-align: left;">
<span style="font-size: large;">remaining at inlet to expansion</span></div>
<div style="text-align: left;">
<span style="font-size: large;">device at all operating conditions</span></div>
<div style="text-align: left;">
<span style="font-size: large;">maximum velocity</span></div>
<div style="text-align: left;">
<span style="font-size: large;">360 fpm (1.8 m/s) 600 fpm (3 m/s)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">old rules for R-22 new rules for R-22</span></div>
<div style="text-align: left;">
<span style="font-size: large;"><br /></span></div>
<div style="text-align: left;">
<span style="font-size: large;">period four</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Liquid Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The new maximum-velocity limit of 600 fpm (3 m/s) is based on preventing</span></div>
<div style="text-align: left;">
<span style="font-size: large;">erosion of the inner surfaces of the pipe.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Sizing Process</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Following are the steps to follow when selecting the proper diameter of the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid line:</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1) Determine the total length of liquid-line piping.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">2) Obtain the amount of subcooling provided by the condenser from the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">manufacturer.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">3) Determine the refrigerant velocity at maximum system capacity.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">4) Select the smallest pipe diameter that will result in acceptable refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">velocity at maximum system capacity.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">5) Calculate the total equivalent length of piping by adding the actual</span></div>
<div style="text-align: left;">
<span style="font-size: large;">measured length of straight pipe to the equivalent length of any fittings to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">be installed in the liquid line.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">6) Determine the pressure drop (based on the total equivalent length) due to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the straight pipe and fittings.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">7) Add the pressure drop due to any accessories installed in the liquid line.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">8) Calculate the loss of subcooling due to pressure drop and to any change in</span></div>
<div style="text-align: left;">
<span style="font-size: large;">elevation, to verify adequate subcooling at the inlet to the expansion</span></div>
<div style="text-align: left;">
<span style="font-size: large;">device.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">From the initial layout, the total measured length of the liquid line can be</span></div>
<div style="text-align: left;">
<span style="font-size: large;">estimated. Again, the refrigerant piping should be routed in the shortest and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">simplest manner possible, minimizing the total length of piping.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Process for Sizing</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1 Determine total length of piping</span></div>
<div style="text-align: left;">
<span style="font-size: large;">2 Obtain subcooling provided by condenser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">3 Determine refrigerant velocity</span></div>
<div style="text-align: left;">
<span style="font-size: large;">4 Select smallest pipe diameter that results in</span></div>
<div style="text-align: left;">
<span style="font-size: large;">acceptable velocity at maximum capacity</span></div>
<div style="text-align: left;">
<span style="font-size: large;">5 Calculate total equivalent length of pipe and fittings</span></div>
<div style="text-align: left;">
<span style="font-size: large;">6 Determine pressure drop due to pipe and fittings</span></div>
<div style="text-align: left;">
<span style="font-size: large;">7 Add pressure drop due to accessories</span></div>
<div style="text-align: left;">
<span style="font-size: large;">8 Calculate loss of subcooling due to pressure drop</span></div>
<div style="text-align: left;">
<span style="font-size: large;">and elevation change </span></div>
<div style="text-align: left;">
<span style="font-size: large;">period four</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Liquid Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The next step is to determine how much subcooling is provided by the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condenser. This is difficult because the amount of subcooling provided by an</span></div>
<div style="text-align: left;">
<span style="font-size: large;">air-cooled condenser depends on many factors, including the total amount of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">heat that must be rejected, the outdoor dry-bulb temperature, the internal</span></div>
<div style="text-align: left;">
<span style="font-size: large;">volume of the liquid line, and the system refrigerant charge.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">To demonstrate, look at an example operating envelope for a system comprised</span></div>
<div style="text-align: left;">
<span style="font-size: large;">of an air-cooled condensing unit (compressors and condenser packaged</span></div>
<div style="text-align: left;">
<span style="font-size: large;">together) and a cooling coil (evaporator). The operating envelope is the entire</span></div>
<div style="text-align: left;">
<span style="font-size: large;">range of cooling loads for the system over the entire range of outdoor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">temperatures at which the system will be operating. Identifying the extreme</span></div>
<div style="text-align: left;">
<span style="font-size: large;">corners of this system operating envelope helps us to understand how the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">amount of subcooling provided by the condenser varies.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">In Figure 58, two of the lines depict the performance of the condensing unit</span></div>
<div style="text-align: left;">
<span style="font-size: large;">operating over a range of cooling loads. One line assumes that the unit</span></div>
<div style="text-align: left;">
<span style="font-size: large;">operates at a constant high outdoor-air (outdoor or OA) temperature, while the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">other line assumes that the same unit operates at a constant low outdoor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">temperature.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The other two lines depict the performance of the evaporator coil operating</span></div>
<div style="text-align: left;">
<span style="font-size: large;">over a range of outdoor-air temperatures. One line assumes that the coil</span></div>
<div style="text-align: left;">
<span style="font-size: large;">operates with a constant high cooling load, while the other line assumes that</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the same coil operates with a constant low cooling load.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">System Operating Envelope</span></div>
<div style="text-align: left;">
<span style="font-size: large;">saturated suction temperature</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condensing unit,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">high OA temperature</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condensing unit,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">low OA temperature</span></div>
<div style="text-align: left;">
<span style="font-size: large;">evaporator,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">high cooling load</span></div>
<div style="text-align: left;">
<span style="font-size: large;">evaporator,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">low cooling load</span></div>
<div style="text-align: left;">
<span style="font-size: large;">system cooling capacity</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period four</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Liquid Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">This operating envelope defines four extreme corners. Condition A depicts the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">system operating with a high cooling load at a high outdoor temperature, and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condition B depicts a low cooling load at the same high outdoor temperature.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Condition C depicts the system operating with a low cooling load at a low</span></div>
<div style="text-align: left;">
<span style="font-size: large;">outdoor temperature, and condition D depicts a high cooling load at the same</span></div>
<div style="text-align: left;">
<span style="font-size: large;">low outdoor temperature.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">A common belief is that the amount of subcooling provided by the condenser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">increases when the outdoor temperature is cooler. But this is not necessarily</span></div>
<div style="text-align: left;">
<span style="font-size: large;">true in systems that use a TXV for the expansion device. Figure 60 shows how</span></div>
<div style="text-align: left;">
<span style="font-size: large;">subcooling changes throughout the operating envelope of an example system.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">When the system operates with a high cooling load and a high outdoor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">temperature (A), the condenser provides 18°F (10°C) of subcooling. When</span></div>
<div style="text-align: left;">
<span style="font-size: large;">operating with the low cooling load at the same high outdoor temperature (B),</span></div>
<div style="text-align: left;">
<span style="font-size: large;">less heat must be rejected by the condenser, allowing it to provide more</span></div>
<div style="text-align: left;">
<span style="font-size: large;">subcooling—21°F (11.7°C).</span></div>
<div style="text-align: left;">
<span style="font-size: large;">System Operating Envelope</span></div>
<div style="text-align: left;">
<span style="font-size: large;">high cooling load,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">high OA temperature</span></div>
<div style="text-align: left;">
<span style="font-size: large;">A</span></div>
<div style="text-align: left;">
<span style="font-size: large;">B</span></div>
<div style="text-align: left;">
<span style="font-size: large;">D</span></div>
<div style="text-align: left;">
<span style="font-size: large;">C</span></div>
<div style="text-align: left;">
<span style="font-size: large;">high cooling load,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">low OA temperature</span></div>
<div style="text-align: left;">
<span style="font-size: large;">low cooling load,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">high OA temperature</span></div>
<div style="text-align: left;">
<span style="font-size: large;">low cooling load,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">low OA temperature</span></div>
<div style="text-align: left;">
<span style="font-size: large;">saturated suction temperature</span></div>
<div style="text-align: left;">
<span style="font-size: large;">system cooling capacity</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 59</span></div>
<div style="text-align: left;">
<span style="font-size: large;">effect of cooling load and outdoor temperature</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Subcooling Leaving Condenser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">A high high 18 (10.0)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">B low high 21 (11.7)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">C low low 13 (7.2)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">D high low 5 (2.8)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">subcooling leaving</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condenser*, °F (°C)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">cooling</span></div>
<div style="text-align: left;">
<span style="font-size: large;">load</span></div>
<div style="text-align: left;">
<span style="font-size: large;">outdoor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">temperature</span></div>
<div style="text-align: left;">
<span style="font-size: large;">* This example system uses a TXV for the expansion device.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 60</span></div>
<div style="text-align: left;">
<span style="font-size: large;">48 TRG-TRC006-EN</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period four</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Liquid Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">When the system operates with the low cooling load at a low outdoor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">temperature (C), the impact of the refrigerant density change reduces the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">subcooling provided by the condenser to 13°F (7.2°C). Finally, when the system</span></div>
<div style="text-align: left;">
<span style="font-size: large;">operates with the high cooling load at the same low outdoor temperature (D),</span></div>
<div style="text-align: left;">
<span style="font-size: large;">subcooling drops to 5°F (2.8°C). At condition D, the mass flow rate of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant is high due to the high cooling load, and the refrigerant density is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">high due to the low outdoor temperature. This results in very little liquid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant remaining in the condenser for subcooling.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The key points here are that the amount of subcooling provided by the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condenser changes within the operating envelope, and this subcooling is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">actually reduced at cooler outdoor temperatures due to the change in</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant density. This example demonstrates that the condenser provides the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">smallest amount of subcooling when the system is operating with a high</span></div>
<div style="text-align: left;">
<span style="font-size: large;">evaporator load at a low outdoor temperature.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Defining the operating envelope for a particular system is no easy task, and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">therefore is generally not done for each project. Determining the amount of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">subcooling provided by the condenser throughout an operating envelope is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">also quite complicated. It requires a model of the entire refrigeration system</span></div>
<div style="text-align: left;">
<span style="font-size: large;">and help from the manufacturer of the condenser. Therefore, if the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">manufacturer of the refrigeration equipment provides recommended line sizes,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">or tools for selecting the optimal line sizes, we suggest that you use them.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">If recommended line sizes are not provided, however, consult the manufacturer</span></div>
<div style="text-align: left;">
<span style="font-size: large;">to determine the amount of subcooling provided by the condenser. For this</span></div>
<div style="text-align: left;">
<span style="font-size: large;">example, we will assume 15°F (8.3°C) of subcooling is provided by the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condenser.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Involve the Manufacturer</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ If provided, use refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line sizes recommended by</span></div>
<div style="text-align: left;">
<span style="font-size: large;">manufacturer</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 61</span></div>
<div style="text-align: left;">
<span style="font-size: large;">TRG-TRC006-EN 49</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period four</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Liquid Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">notes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The chart in Figure 62 shows the velocity of liquid R-22 inside liquid lines of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">various diameters at one particular operating condition—40°F (4.4°C) saturated</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction temperature, 125°F (51.7°C) saturated condensing temperature, 12°F</span></div>
<div style="text-align: left;">
<span style="font-size: large;">(6.7°C) of superheat, 15°F (8.3°C) of subcooling, and 70°F (38.9°C) of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor superheat.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">For the same example 20-ton (70.3-kW) system, the refrigerant velocity inside a</span></div>
<div style="text-align: left;">
<span style="font-size: large;">5/8 in. (15 mm)-diameter pipe is about 520 fpm (2.6 m/s) at this condition.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Again, a computer program can be used to calculate the velocity based on</span></div>
<div style="text-align: left;">
<span style="font-size: large;">actual conditions, but without a program, a chart like this may be useful.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Using the chart in Figure 62, the refrigerant velocity at maximum system</span></div>
<div style="text-align: left;">
<span style="font-size: large;">capacity—20 tons (70.3 kW), for this example—is determined for various pipe</span></div>
<div style="text-align: left;">
<span style="font-size: large;">diameters. Use of the 1/2 in. (12 mm)-diameter pipe results in a refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;"><br /></span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period four</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Liquid Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">velocity that is greater than the recommended upper limit of 600 fpm (3 m/s) for</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid lines, so it should probably not be considered.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">After the velocity inside pipes of various diameters has been determined, the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">smallest acceptable pipe diameter is selected to minimize the system</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant charge. The table in Figure 63 on page 49 shows that 5/8 in. (15 mm)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">is the smallest diameter of pipe that will result in a velocity below the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">recommended upper limit of 600 fpm (3 m/s).</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The next step is to calculate the total equivalent length by adding the actual</span></div>
<div style="text-align: left;">
<span style="font-size: large;">measured length of straight pipe to the equivalent length of any fittings to be</span></div>
<div style="text-align: left;">
<span style="font-size: large;">installed in the liquid line. The equivalent length data for copper fittings used in</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the liquid line is the same as for the suction and discharge lines.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The liquid line for this example 20-ton (70.3-kW) system, shown in Figure 64, is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">100 ft (30.5 m) long. It is constructed entirely of 5/8 in. (15 mm)-diameter pipe</span></div>
<div style="text-align: left;">
<span style="font-size: large;">and contains a total of four long-radius elbows. Based on the “new” equivalent</span></div>
<div style="text-align: left;">
<span style="font-size: large;">length data from Table 1 on page 21, the equivalent length of each elbow of this</span></div>
<div style="text-align: left;">
<span style="font-size: large;">diameter is 0.4 ft (0.12 m). The total equivalent length of this example liquid line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">is calculated to be 101.6 ft (31.0 m).</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Calculate Total Equivalent Length</span></div>
<div style="text-align: left;">
<span style="font-size: large;">evaporator</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condenser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period four</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Liquid Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The next step is to determine the pressure drop due to the straight pipe and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">fittings, based on the calculated total equivalent length. The chart in Figure 65</span></div>
<div style="text-align: left;">
<span style="font-size: large;">shows the pressure drop, per unit of equivalent length, for different pipe</span></div>
<div style="text-align: left;">
<span style="font-size: large;">diameters and capacities. This chart is based on one specific operating</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condition, but is likely to be representative of the condition when the system</span></div>
<div style="text-align: left;">
<span style="font-size: large;">operates at maximum capacity. Alternatively, a computer program can be used</span></div>
<div style="text-align: left;">
<span style="font-size: large;">to determine pressure drop at specific conditions.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">At the maximum capacity of 20 tons (70.3 kW), the pressure drop due to the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">straight pipe and fittings of the liquid line is 17 psi per 100 ft of equivalent</span></div>
<div style="text-align: left;">
<span style="font-size: large;">length (72.2 kPa/10 m), or 17.3 psi (119 kPa).</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Determine Pressure Drop</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period four</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Liquid Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The next step is to add the pressure drop due to any accessories that will be</span></div>
<div style="text-align: left;">
<span style="font-size: large;">installed in the liquid line, and calculate the total pressure drop. The most</span></div>
<div style="text-align: left;">
<span style="font-size: large;">common accessories installed in a liquid line are a filter-drier, a sight glass, a</span></div>
<div style="text-align: left;">
<span style="font-size: large;">solenoid valve, and manual ball valves that are used to isolate portions of the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">system during maintenance, such as when replacing the core of the filter-drier.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The pressure drop for the filter-drier, shown in Figure 66, assumes that it is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">properly sized but dirty.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Assuming that this example system includes a filter-drier, solenoid valve, sight</span></div>
<div style="text-align: left;">
<span style="font-size: large;">glass, and two ball valves, the total pressure drop due to the liquid line is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">27.8 psi (191 kPa).</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Add Pressure Drop of Accessories</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Filter-drier = 6 psi (41.4 kPa)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Solenoid valve = 4 psi (27.6 kPa)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Sight glass = 1 equivalent ft (0.3 m)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Angle valve = 1 psi (6.9 kPa)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Ball valve = 1 equivalent ft (0.3 m)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">solenoid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">valve</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period four</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Liquid Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The next step is to calculate the loss of subcooling due to the liquid-line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pressure drop and any elevation change.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">When the condenser is at a lower elevation than the evaporator, the refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">must overcome the pressure due to a column of liquid refrigerant when flowing</span></div>
<div style="text-align: left;">
<span style="font-size: large;">up to the evaporator. This liquid column causes a pressure drop that results in a</span></div>
<div style="text-align: left;">
<span style="font-size: large;">decrease in the amount of subcooling available at the expansion device. When</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the condenser is at a higher elevation than the evaporator, however, the liquid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">column causes a pressure gain that results in an increase in subcooling.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Most systems will include some vertical risers and some vertical drops in the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid line, but the critical distance is net elevation difference. For example, the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid line in this example system (Figure 67) rises 15 ft (4.6 m) and then later</span></div>
<div style="text-align: left;">
<span style="font-size: large;">drops 11 ft (3.4 m). The vertical rise will cause a pressure drop and the vertical</span></div>
<div style="text-align: left;">
<span style="font-size: large;">drop will cause a pressure gain, but the net effect of these two vertical sections</span></div>
<div style="text-align: left;">
<span style="font-size: large;">will be 4 ft (1.2 m) of rise.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Pressure Drop Due to Elevation</span></div>
<div style="text-align: left;">
<span style="font-size: large;">evaporator</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condenser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">15 ft (4.6 m)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">vertical rise</span></div>
<div style="text-align: left;">
<span style="font-size: large;">creates</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pressure drop</span></div>
<div style="text-align: left;">
<span style="font-size: large;">11 ft (3.4 m)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">vertical drop</span></div>
<div style="text-align: left;">
<span style="font-size: large;">creates</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pressure gain</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period four</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Liquid Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The chart in Figure 68 shows that the magnitude of the associated pressure</span></div>
<div style="text-align: left;">
<span style="font-size: large;">drop (or gain) depends primarily on the temperature (density) of the liquid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant. The greatest pressure drop (or gain) due to this vertical column of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid occurs when the temperature of the liquid refrigerant is the lowest.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Using the example liquid line in Figure 67 on page 53, and assuming a liquidrefrigerant temperature of 110°F (43.3°C), the pressure drop due to the 4 ft (1.2</span></div>
<div style="text-align: left;">
<span style="font-size: large;">m) net liquid-line rise is 1.9 psi (13.4 kPa).</span></div>
<div style="text-align: left;">
<span style="font-size: large;">As you can see, the effect of this liquid column of refrigerant can dramatically</span></div>
<div style="text-align: left;">
<span style="font-size: large;">affect the amount of subcooling available at the expansion device, especially at</span></div>
<div style="text-align: left;">
<span style="font-size: large;">cooler ambient conditions when the condenser is already providing less</span></div>
<div style="text-align: left;">
<span style="font-size: large;">subcooling than it could under design conditions. In fact, it may even use up all</span></div>
<div style="text-align: left;">
<span style="font-size: large;">of the subcooling provided by the condenser, resulting in no subcooling</span></div>
<div style="text-align: left;">
<span style="font-size: large;">remaining at the expansion device.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Historically, the rule-of-thumb has been to assume a pressure drop of 0.5 psi for</span></div>
<div style="text-align: left;">
<span style="font-size: large;">each foot (11.3 kPa/m) of net liquid-line rise.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Pressure Drop Due to Elevation</span></div>
<div style="text-align: left;">
<span style="font-size: large;"><br /></span></div>
<div style="text-align: left;">
<span style="font-size: large;">period four</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Liquid Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Next, the pressure drop due to the elevation change is added to the frictional</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pressure drop due to the straight pipe, fittings, and accessories. For our</span></div>
<div style="text-align: left;">
<span style="font-size: large;">example 20-ton (70.3-kW) system, the total pressure drop due to all of these</span></div>
<div style="text-align: left;">
<span style="font-size: large;">effects is 29.7 psi (204.4 kPa).</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Then, using the chart in Figure 69, this total pressure drop is converted to an</span></div>
<div style="text-align: left;">
<span style="font-size: large;">equivalent loss in subcooling. Assuming a liquid refrigerant temperature of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">110°F (43.3°C), the loss of subcooling is 3 psi/°F (37.3 kPa/°C), or 9.9°F (5.5°C).</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period four</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Liquid Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The last step is to verify that adequate subcooling is available at the inlet to the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">expansion device. This involves subtracting the impact of pressure drop and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">elevation difference from the amount of subcooling provided by the condenser.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">At this condition, 5.1°F (2.8°C) of subcooling is remaining at the inlet to the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">expansion device. This is above the minimum limit of 5°F (2.8°C).</span></div>
<div style="text-align: left;">
<span style="font-size: large;">As mentioned earlier, in the past, a common rule was to limit the pressure drop</span></div>
<div style="text-align: left;">
<span style="font-size: large;">through the liquid line to 6 psi (41 kPa) for a system operating with R-22.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">However, as this example demonstrates, in many cases a much higher pressure</span></div>
<div style="text-align: left;">
<span style="font-size: large;">drop can be tolerated and allows the liquid line to be smaller. This reduces the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant charge, which improves system reliability and lowers the installed</span></div>
<div style="text-align: left;">
<span style="font-size: large;">cost.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Subcooling Remaining at</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Expansion Device</span></div>
<div style="text-align: left;">
<span style="font-size: large;"><br /></span></div>
<div style="text-align: left;">
<span style="font-size: large;">subcooling remaining at expansion device 15 = = F 9.9 – F 5.1F</span></div>
<div style="text-align: left;">
<span style="font-size: large;">subcooling remaining at expansion device 8.3 = = C 5.5 – C 2.8C</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period four</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Liquid Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Other Considerations</span></div>
<div style="text-align: left;">
<span style="font-size: large;">When an evaporator has more than one distributor connected to a single</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigeration circuit, the liquid line should be designed and installed to provide</span></div>
<div style="text-align: left;">
<span style="font-size: large;">equal inlet pressures to the distributors.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">In this example, the liquid line is split and the same sizes and lengths of piping</span></div>
<div style="text-align: left;">
<span style="font-size: large;">are used to make the connections to the expansion devices and distributors.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">This equalizes the pressure drops of the two connections and provides the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">most-balanced expansion-device performance.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">For proper refrigerant distribution into the evaporator coil, one TXV is required</span></div>
<div style="text-align: left;">
<span style="font-size: large;">for each distributor.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">A sight glass is installed as close as practical, upstream of the expansion</span></div>
<div style="text-align: left;">
<span style="font-size: large;">device. This is a fitting that contains a glass window through which the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant entering the expansion device may be viewed and its state</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Evaporator Coil Connections</span></div>
<div style="text-align: left;">
<span style="font-size: large;">TXV</span></div>
<div style="text-align: left;">
<span style="font-size: large;">distributor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">evaporator</span></div>
<div style="text-align: left;">
<span style="font-size: large;">solenoid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">valve</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Refrigerant Accessories</span></div>
<div style="text-align: left;">
<span style="font-size: large;">sight</span></div>
<div style="text-align: left;">
<span style="font-size: large;">glass</span></div>
<div style="text-align: left;">
<span style="font-size: large;">TXV</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">solenoid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">valve</span></div>
<div style="text-align: left;">
<span style="font-size: large;">filter-drier</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period four</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Liquid Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">determined. As mentioned earlier, flashing of refrigerant upstream of the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">expansion device is undesirable. A sight glass can be used to indicate that this</span></div>
<div style="text-align: left;">
<span style="font-size: large;">problem exists.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">A solenoid-operated shutoff valve is typically installed in the liquid line to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">facilitate system pumpdown or to prevent refrigerant migration when the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">system is off. Solenoid valves may also be used to control the flow of liquid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant to multiple sections of the evaporator. In this application, a valve</span></div>
<div style="text-align: left;">
<span style="font-size: large;">would be installed upstream of the TXV for each individually controlled section</span></div>
<div style="text-align: left;">
<span style="font-size: large;">of the evaporator coil.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">A liquid line filter-drier should be installed upstream of, and as close as</span></div>
<div style="text-align: left;">
<span style="font-size: large;">possible to, the solenoid valve and TXV. The filter-drier prevents moisture and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">foreign matter, introduced during the installation process, from damaging the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">solenoid valve or TXV. Manual ball valves should be installed for isolating the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">filter-drier when the core needs to be replaced. It is important to realize that the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">filter-drier is not a cure-all for poor installation practice. The piping must be</span></div>
<div style="text-align: left;">
<span style="font-size: large;">clean, and any air or moisture must be thoroughly evacuated from the system.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Finally, an access port is typically installed in the liquid line in a convenient</span></div>
<div style="text-align: left;">
<span style="font-size: large;">location and is used to charge the system with liquid refrigerant. It is also used</span></div>
<div style="text-align: left;">
<span style="font-size: large;">to measure the amount of subcooling in the system.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">How the liquid line is routed can be important, particularly when the condenser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">is located below the evaporator. As an example, the upper system in Figure 73</span></div>
<div style="text-align: left;">
<span style="font-size: large;">routes the liquid-line riser before a long horizontal run. The lower system</span></div>
<div style="text-align: left;">
<span style="font-size: large;">routes the riser after a long horizontal run.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">In both cases, when the refrigeration circuit shuts off, the liquid refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">inside the vertical riser will drain back into the condenser. In the upper system,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">however, some of the liquid refrigerant from inside the horizontal run will also</span></div>
<div style="text-align: left;">
<span style="font-size: large;">drain back into the condenser. If this quantity of refrigerant is large enough, it</span></div>
<div style="text-align: left;">
<span style="font-size: large;">will fill the condenser and overflow into the discharge line and then into the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor. This can result in compressor lubrication problems, system</span></div>
<div style="text-align: left;">
<span style="font-size: large;">shutdown due to activation of a protective safety device, or mechanical failure.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Liquid Line Routing</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period four</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Liquid Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Alternatively, a check valve can be installed in the liquid line, near the outlet of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the condenser, whenever the liquid line rises above the height of the condenser.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">This check valve will prevent liquid refrigerant from draining back into the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condenser when the system is off.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">A pressure-relief valve is required if both a check valve and a solenoid valve are</span></div>
<div style="text-align: left;">
<span style="font-size: large;">installed in the same liquid line. When the refrigeration circuit is off, these two</span></div>
<div style="text-align: left;">
<span style="font-size: large;">valves trap liquid refrigerant between them. The pressure-relief valve is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">required to relieve the increased pressure that can result when the temperature</span></div>
<div style="text-align: left;">
<span style="font-size: large;">of this trapped refrigerant increases.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Generally, horizontal sections of the liquid line should be pitched to run</span></div>
<div style="text-align: left;">
<span style="font-size: large;">alongside of the accompanying suction or discharge line. This simplifies the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">installation of the line set. Sloping the liquid line in one direction will not always</span></div>
<div style="text-align: left;">
<span style="font-size: large;">prevent the flow of refrigerant in the opposite direction because it may move</span></div>
<div style="text-align: left;">
<span style="font-size: large;">due to the siphon effect.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The refrigerant temperature inside the liquid line is generally higher than that of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the surrounding air. Therefore, insulation is not typically required. In fact, heat</span></div>
<div style="text-align: left;">
<span style="font-size: large;">loss may be desirable because it provides additional subcooling. If the liquid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line is routed through areas that are significantly warmer than the liquid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant (such as unconditioned attic spaces or boiler rooms), however, the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">sections of the liquid line that are exposed to the warmer temperatures should</span></div>
<div style="text-align: left;">
<span style="font-size: large;">be insulated to prevent loss of subcooling.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Other Considerations</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Pitch horizontal sections to run alongside</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction or discharge line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Insulate lines that are routed through very</span></div>
<div style="text-align: left;">
<span style="font-size: large;">warm spaces</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period five</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Hot-Gas Bypass Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The last refrigerant line to be considered is the hot-gas bypass line. The hot-gas</span></div>
<div style="text-align: left;">
<span style="font-size: large;">bypass line diverts hot, high-pressure refrigerant vapor from the discharge line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">to the low-pressure side of the refrigeration system. This adds a “false load” to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the system that can help stabilize the suction pressure and temperature.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Hot-gas bypass is sometimes used to help prevent evaporator frosting in directexpansion (DX) applications, or in applications where the compressor cannot</span></div>
<div style="text-align: left;">
<span style="font-size: large;">be allowed to cycle on and off, such as a process-cooling application.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">In general, however, hot-gas bypass should be avoided for most comfortcooling applications. It increases the refrigerant charge in the system, adds</span></div>
<div style="text-align: left;">
<span style="font-size: large;">more paths for potential refrigerant leaks, and increases the likelihood of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant-distribution and oil-return problems. It also increases the first cost of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the system, and the operating cost, because it prevents compressors from</span></div>
<div style="text-align: left;">
<span style="font-size: large;">cycling off with fluctuating loads.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period five</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Hot-Gas Bypass Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Refrigerant Piping</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period five</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Hot-Gas Bypass Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Similar to the discharge line, the refrigerant flowing through the hot-gas bypass</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line is in the form of a hot, high-pressure vapor. However, unlike the discharge</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line, the minimum velocity is difficult to determine. A typical hot-gas bypass</span></div>
<div style="text-align: left;">
<span style="font-size: large;">valve is a modulating valve, so the refrigerant velocity through the valve and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">piping can range all the way from zero flow to full flow. At times, the refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">velocity inside a given pipe diameter will fall below the minimum velocity</span></div>
<div style="text-align: left;">
<span style="font-size: large;">required to carry oil droplets.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Therefore, it is not possible to select a pipe diameter that is small enough to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">move oil at all valve positions. The hot-gas bypass line should be sized as small</span></div>
<div style="text-align: left;">
<span style="font-size: large;">as possible, without the maximum velocity being high enough to cause</span></div>
<div style="text-align: left;">
<span style="font-size: large;">objectionable noise. Because the hot-gas bypass line is basically an extension</span></div>
<div style="text-align: left;">
<span style="font-size: large;">of the discharge line, the recommended maximum velocity is 3,500 fpm</span></div>
<div style="text-align: left;">
<span style="font-size: large;">(17.5 m/s). Selecting the smallest possible line size also minimizes the amount</span></div>
<div style="text-align: left;">
<span style="font-size: large;">of oil and condensed refrigerant that could be trapped in the hot-gas bypass</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Also, the hot-gas bypass line must be installed so that oil and condensed</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant can freely drain out of all sections of the line, at all operating</span></div>
<div style="text-align: left;">
<span style="font-size: large;">conditions.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">hot-gas bypass line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Requirements for Sizing and Routing</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Ensure that oil and refrigerant are not trapped</span></div>
<div style="text-align: left;">
<span style="font-size: large;">in piping</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Avoid excessive noise</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Proper routing is more critical than pipe</span></div>
<div style="text-align: left;">
<span style="font-size: large;">diameter</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period five</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Hot-Gas Bypass Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Hot-Gas Bypass to Evaporator Inlet</span></div>
<div style="text-align: left;">
<span style="font-size: large;">In a DX application, there are two bypass methods that are commonly used.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The first, and preferred, method bypasses refrigerant vapor from the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor discharge line to the inlet of the evaporator. Sensing a decrease in</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction pressure, the hot-gas bypass valve opens to bypass hot refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">vapor from the compressor discharge line to the inlet of the evaporator,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">between the TXV and the distributor. This adds a “false load” to the evaporator</span></div>
<div style="text-align: left;">
<span style="font-size: large;">and increases the suction pressure (and temperature).</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The principal advantage of hot-gas bypass to the evaporator inlet is that the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant velocity inside the evaporator and the suction line is higher at low</span></div>
<div style="text-align: left;">
<span style="font-size: large;">loads. This promotes a uniform movement of oil through the evaporator and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the suction line.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Due to the widely varying velocity in the hot-gas bypass line, the selected</span></div>
<div style="text-align: left;">
<span style="font-size: large;">diameter of the pipe is not as critical as its routing. Install the hot-gas bypass</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Hot-Gas Bypass to Evaporator Inlet</span></div>
<div style="text-align: left;">
<span style="font-size: large;">evaporator</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condenser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">hot-gas</span></div>
<div style="text-align: left;">
<span style="font-size: large;">bypass valve</span></div>
<div style="text-align: left;">
<span style="font-size: large;">TXV</span></div>
<div style="text-align: left;">
<span style="font-size: large;">distributor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 77</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Hot-Gas Bypass Valve Installation</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condenser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">hot-gas</span></div>
<div style="text-align: left;">
<span style="font-size: large;">bypass valve</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pitch back toward</span></div>
<div style="text-align: left;">
<span style="font-size: large;">discharge line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pilot</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">discharge</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pitch away</span></div>
<div style="text-align: left;">
<span style="font-size: large;">from hot-gas</span></div>
<div style="text-align: left;">
<span style="font-size: large;">bypass valve</span></div>
<div style="text-align: left;">
<span style="font-size: large;">hot-gas</span></div>
<div style="text-align: left;">
<span style="font-size: large;">bypass line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period five</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Hot-Gas Bypass Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">valve above the discharge line and close to the compressor. Pitch the section of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe between the discharge line and the hot-gas bypass valve so oil will drain</span></div>
<div style="text-align: left;">
<span style="font-size: large;">back into the discharge line.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">When using a pressure-actuated hot-gas bypass valve, tap the pilot line for the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">valve close to the compressor inlet. This pilot line senses suction pressure, to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">which the valve responds by modulating open or closed. Pitch the piping</span></div>
<div style="text-align: left;">
<span style="font-size: large;">downstream of the hot-gas bypass valve so that oil or condensed refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">will drain away from the valve, toward the evaporator.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">If the hot-gas bypass line includes a vertical riser of any height, or if the line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">does not allow free drainage from the valve to the evaporator, the retention of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">oil or condensed refrigerant within the riser must be considered. As mentioned,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">because the refrigerant velocity within the hot-gas bypass line varies over a</span></div>
<div style="text-align: left;">
<span style="font-size: large;">wide range, no pipe, regardless of its diameter, can ensure adequate velocity to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">carry oil up a riser of any height. Oil will collect at the base of the riser when the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">hot-gas bypass valve throttles to lower flow rates.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">This problem is commonly addressed by installing a small oil-return line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">between the base of the riser and the suction line. First, a drain leg is provided</span></div>
<div style="text-align: left;">
<span style="font-size: large;">at the base of the riser to collect the oil and condensed refrigerant. This short</span></div>
<div style="text-align: left;">
<span style="font-size: large;">section of pipe should be about 12 in (300 mm) long and be the same diameter</span></div>
<div style="text-align: left;">
<span style="font-size: large;">as the riser.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Next, the oil-return line is connected to the side of the drain leg to prevent any</span></div>
<div style="text-align: left;">
<span style="font-size: large;">foreign material from plugging the tube. This oil-return line is constructed of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">1/8 in. (3 mm)-diameter copper tubing and should be at least 5 ft (1.5 m) in</span></div>
<div style="text-align: left;">
<span style="font-size: large;">length. This length is required to create the necessary pressure drop between</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the high-pressure and low-pressure sides of the system, yet this tubing is large</span></div>
<div style="text-align: left;">
<span style="font-size: large;">enough to drain oil and liquid refrigerant from the drain leg. If the oil-return line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">must be longer than 5 ft (1.5 m), 1/4 in. (6 mm)-diameter tubing can be used for</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the rest of the distance.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Hot-Gas Bypass Risers</span></div>
<div style="text-align: left;">
<span style="font-size: large;">hot-gas</span></div>
<div style="text-align: left;">
<span style="font-size: large;">bypass riser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">drain leg</span></div>
<div style="text-align: left;">
<span style="font-size: large;">oil-return</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condenser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">hot-gas</span></div>
<div style="text-align: left;">
<span style="font-size: large;">bypass valve</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period five</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Hot-Gas Bypass Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The hot-gas bypass line is then piped to the evaporator inlet. It must be</span></div>
<div style="text-align: left;">
<span style="font-size: large;">connected to the top of the pipe, between the TXV and the distributor. Any hotgas bypass piping upstream of this connection should be pitched so that oil or</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condensed refrigerant will drain toward the evaporator.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">An orifice-type distributor is typically not able to permit adequate flow of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant vapor through the orifice. If this type of distributor is used, the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">orifice must be relocated upstream of the point at which the hot-gas bypass line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">connects to the distributor.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">When the evaporator contains multiple distributors on a single refrigeration</span></div>
<div style="text-align: left;">
<span style="font-size: large;">circuit, the hot-gas bypass line should be piped to each distributor that is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">“active” when the hot-gas bypass valve opens. The evaporator shown in</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 80 contains two distributors on the refrigeration circuit, each equipped</span></div>
<div style="text-align: left;">
<span style="font-size: large;">with a solenoid valve. In this example, the top solenoid valve closes when the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor unloads. Only the bottom distributor is “active” at minimum</span></div>
<div style="text-align: left;">
<span style="font-size: large;">capacity when the hot-gas bypass valve opens. Therefore, the hot-gas bypass</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pipe only connects to the bottom distributor.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">hot-gas bypass line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Connection to Evaporator</span></div>
<div style="text-align: left;">
<span style="font-size: large;">evaporator</span></div>
<div style="text-align: left;">
<span style="font-size: large;">distributor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">hot-gas</span></div>
<div style="text-align: left;">
<span style="font-size: large;">bypass line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">solenoid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">valve</span></div>
<div style="text-align: left;">
<span style="font-size: large;">TXV</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period five</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Hot-Gas Bypass Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The evaporator shown in Figure 81 also contains two distributors on a single</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigeration circuit, but it only contains one solenoid valve. In this example, the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">solenoid valve closes only after the last compressor on the circuit shuts off.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Both distributors are “active” at all times and the hot-gas bypass pipe must be</span></div>
<div style="text-align: left;">
<span style="font-size: large;">connected to both distributors.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">When the hot-gas bypass line is piped to more than one distributor, check</span></div>
<div style="text-align: left;">
<span style="font-size: large;">valves should be installed in each section of pipe that feeds a distributor.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Without these check valves, a path is created between coil circuits whenever</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the hot-gas bypass valve is closed. The coil circuits will become unequally</span></div>
<div style="text-align: left;">
<span style="font-size: large;">loaded and refrigerant will travel from the outlet of one TXV into the section of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">coil that is served by a different TXV. This will result in the loss of superheat</span></div>
<div style="text-align: left;">
<span style="font-size: large;">control and potential compressor damage.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">hot-gas bypass line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Connection to Evaporator</span></div>
<div style="text-align: left;">
<span style="font-size: large;">evaporator</span></div>
<div style="text-align: left;">
<span style="font-size: large;">distributor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">hot-gas</span></div>
<div style="text-align: left;">
<span style="font-size: large;">bypass line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">solenoid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">valve</span></div>
<div style="text-align: left;">
<span style="font-size: large;">check</span></div>
<div style="text-align: left;">
<span style="font-size: large;">valves</span></div>
<div style="text-align: left;">
<span style="font-size: large;">TXV</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period five</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Hot-Gas Bypass Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Hot-Gas Bypass to the Suction Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The second bypass method conducts refrigerant vapor from the compressor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">discharge line to the suction line. This method requires an additional expansion</span></div>
<div style="text-align: left;">
<span style="font-size: large;">valve, called a liquid-injection valve. The remote bulb of this liquid-injection</span></div>
<div style="text-align: left;">
<span style="font-size: large;">valve is attached to the suction line near the inlet to the compressor. When</span></div>
<div style="text-align: left;">
<span style="font-size: large;">reduced suction pressure causes the hot-gas bypass valve to open, the liquidinjection valve senses the resulting rise in suction temperature and opens to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">mix liquid refrigerant with the bypassed refrigerant vapor. The hot refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">vapor causes the liquid refrigerant to vaporize, cooling the mixture and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">stabilizing the suction pressure.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The advantage of this method is that it requires less actual piping than</span></div>
<div style="text-align: left;">
<span style="font-size: large;">bypassing hot gas to the evaporator inlet. However, the disadvantage is that the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant velocity inside the evaporator and suction line (upstream of the hotgas bypass connection) can drop very low when the hot-gas bypass valve is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">open. This may result in oil being trapped in the evaporator and the suction</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line. For this reason, this method is only acceptable in applications where the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">evaporator and the suction line are able to freely drain to the point at which the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">hot-gas bypass line connects into the suction line. Therefore, hot-gas bypass to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the evaporator inlet is the preferred method.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Hot-Gas Bypass to Suction Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">evaporator</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condenser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">hot-gas</span></div>
<div style="text-align: left;">
<span style="font-size: large;">bypass valve</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid-injection</span></div>
<div style="text-align: left;">
<span style="font-size: large;">valve</span></div>
<div style="text-align: left;">
<span style="font-size: large;">TXV</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period five</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Hot-Gas Bypass Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Again, routing of the hot-gas bypass piping is critical. Install the hot-gas bypass</span></div>
<div style="text-align: left;">
<span style="font-size: large;">valve above the compressor discharge and close to the compressor. Pitch the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">section of pipe between the discharge line and the hot-gas bypass valve so that</span></div>
<div style="text-align: left;">
<span style="font-size: large;">oil will drain back into the discharge line. Tap the pilot line for the hot-gas</span></div>
<div style="text-align: left;">
<span style="font-size: large;">bypass valve close to the compressor inlet, and pitch the piping downstream of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the hot-gas bypass valve so that oil will drain away from the valve, toward the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction line.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">A separate pipe routes liquid refrigerant from the liquid line to mix with the hot,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">bypassed refrigerant vapor. This mixture is then piped into the suction line at</span></div>
<div style="text-align: left;">
<span style="font-size: large;">an angle, at least 5 ft (1.5 m) upstream of the compressor inlet, and upstream of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the pilot line tap for the hot-gas bypass valve. This angled connection promotes</span></div>
<div style="text-align: left;">
<span style="font-size: large;">mixing, and the minimum distance helps ensure complete vaporization of the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid refrigerant before it reaches the compressor.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The liquid-injection line contains a thermal expansion valve, called a liquidinjection valve. The remote bulb for the liquid-injection valve is attached to the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">suction line, downstream of the point at which the hot gas enters the suction</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line. This valve is adjusted to maintain between 30°F and 35°F (-1°C and 1.5°C)</span></div>
<div style="text-align: left;">
<span style="font-size: large;">of superheat at the inlet to the compressor. A solenoid valve is installed</span></div>
<div style="text-align: left;">
<span style="font-size: large;">upstream of the liquid-injection valve to shut off the flow of liquid refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">whenever the hot-gas bypass valve is closed.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">hot-gas bypass line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Connection to Suction Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condenser</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor suction line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">hot-gas</span></div>
<div style="text-align: left;">
<span style="font-size: large;">bypass valve</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid-injection</span></div>
<div style="text-align: left;">
<span style="font-size: large;">valve</span></div>
<div style="text-align: left;">
<span style="font-size: large;">solenoid</span></div>
<div style="text-align: left;">
<span style="font-size: large;">valve</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period five</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Hot-Gas Bypass Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Other Considerations</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The hot-gas bypass valve, and the diameter of the hot-gas bypass line, are</span></div>
<div style="text-align: left;">
<span style="font-size: large;">selected based on the maximum amount of refrigerant vapor that will be</span></div>
<div style="text-align: left;">
<span style="font-size: large;">bypassed. This depends on the application and the purpose of the hot-gas</span></div>
<div style="text-align: left;">
<span style="font-size: large;">bypass system.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">For a traditional comfort-cooling application, the hot-gas bypass valve is used</span></div>
<div style="text-align: left;">
<span style="font-size: large;">to modulate the amount of refrigerant vapor bypassed to maintain the suction</span></div>
<div style="text-align: left;">
<span style="font-size: large;">temperature at a setpoint, such as 28°F (-2.2°C). This typically requires the valve</span></div>
<div style="text-align: left;">
<span style="font-size: large;">to only open when the cooling load on the system drops below the minimum</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor capacity.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">For example, consider the same 20-ton (70.3-kW), single-circuit system that can</span></div>
<div style="text-align: left;">
<span style="font-size: large;">unload to a minimum capacity of 10 tons (35.2 kW). The hot-gas bypass valve</span></div>
<div style="text-align: left;">
<span style="font-size: large;">and line would probably be sized for 10 tons (35.2 kW) of capacity or less.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Assuming a maximum bypass capacity of 10 tons (35.2 kW), the refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">velocity is determined for various pipe diameters using the chart in Figure 43</span></div>
<div style="text-align: left;">
<span style="font-size: large;">on page 34.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">As explained at the beginning of this period, the diameter of the hot-gas bypass</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line should be as small as possible while preventing the maximum velocity</span></div>
<div style="text-align: left;">
<span style="font-size: large;">from exceeding the recommended upper limit of 3,500 fpm (17.5 m/s). For this</span></div>
<div style="text-align: left;">
<span style="font-size: large;">example system, a 3/4 in. (18 mm)-diameter pipe is selected. If the overall</span></div>
<div style="text-align: left;">
<span style="font-size: large;">length of the hot-gas bypass line exceeds 75 ft (23 m), special precautions,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">including increasing the line size, may be required.</span></div>
<div style="text-align: left;">
<span style="font-size: large;"><br /></span></div>
<div style="text-align: left;">
<span style="font-size: large;">period five</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Hot-Gas Bypass Line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The full length of the hot-gas bypass line must be insulated to prevent the hot</span></div>
<div style="text-align: left;">
<span style="font-size: large;">refrigerant vapor from condensing before it reaches the evaporator.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">As the length of the hot-gas bypass line increases, the risk of refrigerant vapor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">condensing inside the line increases, even if the line is insulated. This can cause</span></div>
<div style="text-align: left;">
<span style="font-size: large;">a problem when the hot-gas bypass valve opens, because the refrigerant vapor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">could force a slug of liquid refrigerant into the evaporator. This over-feeding of</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the evaporator may cause liquid refrigerant to enter the suction line, possibly</span></div>
<div style="text-align: left;">
<span style="font-size: large;">slugging the compressor. For this reason, the overall length of the hot-gas</span></div>
<div style="text-align: left;">
<span style="font-size: large;">bypass line should be as short as possible.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">If the refrigeration system includes a pump-down cycle, then a solenoid valve</span></div>
<div style="text-align: left;">
<span style="font-size: large;">must be installed in the hot-gas bypass line. A pump-down cycle closes the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">liquid-line solenoid valve to stop the flow of refrigerant into the evaporator, and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">allows the compressor to run for a short period of time. This pumps refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">from the low-pressure side of the system (evaporator and suction line) to the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">high-pressure side of the system (discharge line, condenser, and liquid line).</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The solenoid valve in the hot-gas bypass line must also close when the system</span></div>
<div style="text-align: left;">
<span style="font-size: large;">begins the pump-down cycle, to prevent the high-pressure refrigerant vapor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">from migrating to the low-pressure side of the system. Some hot-gas bypass</span></div>
<div style="text-align: left;">
<span style="font-size: large;">valves are equipped with an integral solenoid that can be used to hold the valve</span></div>
<div style="text-align: left;">
<span style="font-size: large;">closed for this purpose.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">hot-gas bypass line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Other Considerations</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Insulate entire line to prevent refrigerant vapor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">from condensing</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Minimize overall length of the line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Install solenoid valve if system includes a</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pump-down cycle</span></div>
<div style="text-align: left;">
<span style="font-size: large;">We will now review the main concepts that were covered in this clinic regarding</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the design and installation of the interconnecting piping for vapor-compression</span></div>
<div style="text-align: left;">
<span style="font-size: large;">air-conditioning systems.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">As discussed in Period One, when a refrigeration system includes fieldassembled refrigerant piping, the primary design goals are generally to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">maximize system reliability and minimize installed cost. When the refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">piping is designed and installed, it is imperative that the following requirements</span></div>
<div style="text-align: left;">
<span style="font-size: large;">are met:</span></div>
<div style="text-align: left;">
<span style="font-size: large;"> Return oil to the compressor at all operating conditions</span></div>
<div style="text-align: left;">
<span style="font-size: large;"> Ensure that only liquid refrigerant (no vapor) enters the expansion device</span></div>
<div style="text-align: left;">
<span style="font-size: large;"> Minimize system capacity loss that is caused by pressure drop through the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">piping</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period six</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Review</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Refrigerant Piping</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Figure 86</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Review—Period One</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Refrigerant Piping Requirements</span></div>
<div style="text-align: left;">
<span style="font-size: large;">◆ Return oil to compressor</span></div>
<div style="text-align: left;">
<span style="font-size: large;">◆ Ensure that only liquid refrigerant (no vapor) enters</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the expansion device</span></div>
<div style="text-align: left;">
<span style="font-size: large;">◆ Minimize system capacity loss</span></div>
<div style="text-align: left;">
<span style="font-size: large;">◆ Minimize refrigerant charge</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ If provided, use line sizes recommended</span></div>
<div style="text-align: left;">
<span style="font-size: large;">by the manufacturer</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period six</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Review</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period six</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Review Minimize the total refrigerant charge in the system to improve reliability and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">minimize installed cost</span></div>
<div style="text-align: left;">
<span style="font-size: large;">If the manufacturer of the refrigeration equipment provides recommended line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">sizes, or tools for selecting the proper line sizes, use those line sizes.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Period Two reviewed the design of the suction line. The diameter of the suction</span></div>
<div style="text-align: left;">
<span style="font-size: large;">line should be selected small enough so the refrigerant velocity is high enough</span></div>
<div style="text-align: left;">
<span style="font-size: large;">to move oil, at all steps of compressor unloading. However, the pipe diameter</span></div>
<div style="text-align: left;">
<span style="font-size: large;">should be as large as possible to minimize pressure drop, maximize system</span></div>
<div style="text-align: left;">
<span style="font-size: large;">capacity and efficiency, and avoid causing objectionable noise.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The minimum allowable velocity in a suction line varies based on the diameter</span></div>
<div style="text-align: left;">
<span style="font-size: large;">of the pipe. The smaller the pipe diameter, the less velocity is required to move</span></div>
<div style="text-align: left;">
<span style="font-size: large;">the oil. Long line lengths and the associated higher pressure drop can be</span></div>
<div style="text-align: left;">
<span style="font-size: large;">tolerated, assuming that the loss of system capacity and efficiency is acceptable</span></div>
<div style="text-align: left;">
<span style="font-size: large;">for the given application. Of course, it is still good practice to minimize pressure</span></div>
<div style="text-align: left;">
<span style="font-size: large;">drop.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Review—Period Two</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Suction line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">◆ Ensure adequate velocity to return oil to the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor at all steps of unloading</span></div>
<div style="text-align: left;">
<span style="font-size: large;">◆ Avoid excessive noise</span></div>
<div style="text-align: left;">
<span style="font-size: large;">◆ Minimize system capacity and efficiency loss</span></div>
<div style="text-align: left;">
<span style="font-size: large;">72 TRG-TRC006-EN</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period six</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Review</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Period Three discussed the discharge line. Similar to the suction line, the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">diameter of the discharge line must be small enough that the refrigerant</span></div>
<div style="text-align: left;">
<span style="font-size: large;">velocity is high enough to move oil, at all steps of compressor unloading.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">However, the pipe diameter should be as large as possible to minimize</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pressure drop, maximize system efficiency, and avoid causing objectionable</span></div>
<div style="text-align: left;">
<span style="font-size: large;">noise.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">The liquid line was the focus of Period Four. The liquid line must be designed</span></div>
<div style="text-align: left;">
<span style="font-size: large;">and installed to ensure that only liquid refrigerant (no vapor) enters the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">expansion device. This requires the condenser to provide adequate subcooling,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">and the pressure drop through the liquid line and accessories must not be high</span></div>
<div style="text-align: left;">
<span style="font-size: large;">enough to cause flashing upstream of the expansion device.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">An understanding of the entire refrigeration system, not just the piping, is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">required to select the optimal liquid line size. The diameter of the liquid line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">must be as small as possible to minimize the quantity of refrigerant in the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Review—Period Three</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Discharge line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">◆ Ensure adequate velocity to return oil to the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">compressor at all steps of unloading</span></div>
<div style="text-align: left;">
<span style="font-size: large;">◆ Avoid excessive noise</span></div>
<div style="text-align: left;">
<span style="font-size: large;">◆ Minimize efficiency loss</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Review—Period Four</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Liquid line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">◆ Ensure that only liquid refrigerant enters the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">expansion device</span></div>
<div style="text-align: left;">
<span style="font-size: large;">◆ Minimize refrigerant charge</span></div>
<div style="text-align: left;">
<span style="font-size: large;">◆ Avoid excessive noise and pipe erosion</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period six</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Review</span></div>
<div style="text-align: left;">
<span style="font-size: large;">system and minimize the impact of changes in refrigerant density on the ability</span></div>
<div style="text-align: left;">
<span style="font-size: large;">of the condenser to provide subcooling. This improves system reliability and</span></div>
<div style="text-align: left;">
<span style="font-size: large;">minimizes the installed cost. However, if the pipe is too small, the increased</span></div>
<div style="text-align: left;">
<span style="font-size: large;">pressure drop may cause flashing upstream of the expansion device, and the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">high velocity may result in objectionable noise or erosion to the inside surfaces</span></div>
<div style="text-align: left;">
<span style="font-size: large;">of the piping.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Period Five discussed the importance of proper routing when hot-gas bypass is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">to be used. The two most common methods are hot-gas bypass to the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">evaporator inlet and hot-gas bypass to the suction line. Hot-gas bypass to the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">evaporator inlet is preferred because the refrigerant velocity in the evaporator</span></div>
<div style="text-align: left;">
<span style="font-size: large;">and the suction line is higher at low loads, resulting in improved oil return.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Because the hot-gas bypass valve modulates from full flow down to zero flow,</span></div>
<div style="text-align: left;">
<span style="font-size: large;">at times the refrigerant velocity will fall below the minimum velocity required to</span></div>
<div style="text-align: left;">
<span style="font-size: large;">carry oil droplets. Therefore, it is not possible to select a pipe diameter that is</span></div>
<div style="text-align: left;">
<span style="font-size: large;">small enough to move oil at all valve positions. The hot-gas bypass line must</span></div>
<div style="text-align: left;">
<span style="font-size: large;">be designed and installed so that oil and condensed refrigerant can freely drain</span></div>
<div style="text-align: left;">
<span style="font-size: large;">out of all sections of the line, at all operating conditions.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">When used, the overall length of the hot-gas bypass line should be as short as</span></div>
<div style="text-align: left;">
<span style="font-size: large;">possible. In general, however, hot-gas bypass should be avoided for most</span></div>
<div style="text-align: left;">
<span style="font-size: large;">comfort-cooling applications.</span></div>
<div style="text-align: left;">
<span style="font-size: large;">Review—Period Five</span></div>
<div style="text-align: left;">
<span style="font-size: large;">▲ Hot-gas bypass line</span></div>
<div style="text-align: left;">
<span style="font-size: large;">◆ Ensure that oil and refrigerant are not trapped in the</span></div>
<div style="text-align: left;">
<span style="font-size: large;">piping</span></div>
<div style="text-align: left;">
<span style="font-size: large;">◆ Avoid excessive noise</span></div>
<div style="text-align: left;">
<span style="font-size: large;">◆ Proper routing is more critical than pipe diameter</span></div>
<div style="text-align: left;">
<span style="font-size: large;">period six</span></div>
<div style="text-align: left;">
<br /></div>
<div style="text-align: left;">
<br /></div>
<div style="text-align: left;">
From*book-Trane Refrigerant Piping</div>
</div>
mohammed saifhttp://www.blogger.com/profile/04808794259319186322noreply@blogger.com0tag:blogger.com,1999:blog-530905379816001374.post-29607538876814768222018-07-25T03:22:00.001-07:002018-07-25T03:22:18.996-07:00الحسابات والمراعاة التصميمية الرئيسية لاختيار الchiller<div dir="rtl" style="text-align: right;" trbidi="on">
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjNrzhxkRf520gk67uTgHGRPnU4zk3Z5hT5OsZAXHDxIBG7uJYrGLoCBkHUlMkdbCG3qNb4GeMIAqkfFFbfuPiE4oMAXj2FcrwmJU_w5HCcCAbNavLH6pQ814l4ekPKVkZIpP8uq0JklQhR/s1600/0-DjVxPYM0CTkuzCJe-.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="935" data-original-width="1600" height="232" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjNrzhxkRf520gk67uTgHGRPnU4zk3Z5hT5OsZAXHDxIBG7uJYrGLoCBkHUlMkdbCG3qNb4GeMIAqkfFFbfuPiE4oMAXj2FcrwmJU_w5HCcCAbNavLH6pQ814l4ekPKVkZIpP8uq0JklQhR/s400/0-DjVxPYM0CTkuzCJe-.png" width="400" /></a></div>
<span style="font-size: large;"><br /></span>
<span style="font-size: large;">تستخدم Water chillers في مجموعة متنوعة من تطبيقات التبريد وتكييف الهواء. يتم استخدامها لصنع المياه الباردة التي يمكن نقلها في جميع أنحاء منشأة باستخدام المضخات والأنابيب. يمكن تمرير هذا الماء البارد من خلال أنابيب لفائف لتبريد الهواء في تطبيق تكييف الهواء ، أو يمكن أن توفر التبريد لعملية التصنيع أو الصناعية.</span><br />
<span style="font-size: large;">• تتباين Water chillers التي تستخدم دورة التبريد بضغط البخار باختلاف نوع الضاغط المستخدم.</span><br />
<span style="font-size: large;">• يتم استخدام الضواغط الترددية أو التمرير أو الحلزونية الدوارة (أو البرغي) أو الضواغط الطاردة المركزية عمومًا في مبردات المياه التي تستخدم دورة التبريد بضغط البخار.</span><br />
<span style="font-size: large;">• ﺗﺴﺘﺨﺪم أﺟﻬﺰة ﺗﺒﺮﻳﺪ اﻟﻤﻴﺎﻩ ﻟﻼﻣﺘﺼﺎص دورة ﺗﺒﺮﻳﺪ اﻻﻣﺘﺼﺎص وﻻ ﺗﺴﺘﺨﺪم ﺿﺎﻏﻄًﺎ ﻣﻴﻜﺎﻧﻴﻜﻴًﺎ</span><br />
<span style="font-size: large;">• هناك فروقان أساسيتان بين دورة التبريد الامتصاصية ودورة تبريد ضغط البخار.</span><br />
<span style="font-size: large;">• الأول هو أن يتم استبدال الضاغط عن طريق امتصاص ، ومضخة ، ومولد.</span><br />
<span style="font-size: large;">• والثاني هو أنه بالإضافة إلى المبرد ، تستخدم دورة التبريد الامتصاصية سائلًا ثانويًا يسمى الماص.</span><br />
<span style="font-size: large;">• تستخدم دورة التبريد بضغط البخار عموماً الهالوكربون (مثل HCFC-123 ، و HCFC-22 ، و HFC-134a ، وما إلى ذلك) كمبرد. تستخدم دورة التبريد الخاصة بالامتصاص التي نوقشت هنا الماء المقطر كمبرد.</span><br />
<span style="font-size: large;">• تشمل كلا الدورتين أيضًا جهازًا لزيادة ضغط جهاز التبريد وجهاز توسيع للحفاظ على فرق الضغط الداخلي ، وهو أمر مهم لعملية نقل الحرارة بشكل عام.</span><br />
<span style="font-size: large;">ميزات مبرد المياه أنظمة التبريد</span><br />
<span style="font-size: large;">• من السهل السيطرة على أي وحدة FCU بشكل منفصل.</span><br />
<span style="font-size: large;">• سهل الصيانة.</span><br />
<span style="font-size: large;">• انخفاض تكاليف التشغيل.</span><br />
<span style="font-size: large;">خطوات التصميم</span><br />
<span style="font-size: large;">• ماذا نصمم؟</span><br />
<span style="font-size: large;">1. احسب GPM</span><br />
<span style="font-size: large;">2. عامل خسارة الاحتكاك في كل الأنابيب</span><br />
<span style="font-size: large;">• احسب GPM</span><br />
<span style="font-size: large;">GPM = Q / (500 * فرق درجة الحرارة)</span><br />
<span style="font-size: large;">ثم نقوم بحساب إجمالي GPM</span><br />
<span style="font-size: large;">مراقبة</span><br />
<span style="font-size: large;">• صمام ثنائي الاتجاه</span><br />
<span style="font-size: large;">•<span class="Apple-tab-span" style="white-space: pre;"> </span>ثلاثي صمام</span><br />
<span style="font-size: large;">تذكر</span><br />
<span style="font-size: large;">• قدرة المبرد</span><br />
<span style="font-size: large;">• عدد المبردات</span><br />
<span style="font-size: large;">• لاختيار chiller:</span><br />
<span style="font-size: large;">- تبريد الهواء أو تبريد المياه</span><br />
<span style="font-size: large;">- مجموع GPM</span><br />
<span style="font-size: large;">-<span class="Apple-tab-span" style="white-space: pre;"> </span>الفرق في درجة الحرارة</span><br />
<span style="font-size: large;">- درجة الحرارة المحيطة</span><br />
<span style="font-size: large;"><br /></span>
<span style="font-size: large;"><br /></span>
<span style="font-size: large;">ساعدونة بتعليقاتكم ومشاركاتكم لنبدع اكثر</span><br />
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<br /></div>
</div>
mohammed saifhttp://www.blogger.com/profile/04808794259319186322noreply@blogger.com0tag:blogger.com,1999:blog-530905379816001374.post-17179506130655322202018-07-25T02:49:00.003-07:002018-07-25T02:49:55.404-07:00اساسيات ال HVAC<div dir="rtl" style="text-align: right;" trbidi="on">
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghpZ60ZPc_OkgvbnZn5SpPvSdX7_6OQ8B-Rpuue4M5CcIITPcFlHL9OaLftpxX3DxDVLmBMNsLSNbnKMItXR77FjEXjNfgdjbvcq7c7HFyiDdHatXk5jBa_F9HfJo_8f0HjVGS3KdSqLo4/s1600/hvac-1-638.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: large;"><img border="0" data-original-height="479" data-original-width="638" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghpZ60ZPc_OkgvbnZn5SpPvSdX7_6OQ8B-Rpuue4M5CcIITPcFlHL9OaLftpxX3DxDVLmBMNsLSNbnKMItXR77FjEXjNfgdjbvcq7c7HFyiDdHatXk5jBa_F9HfJo_8f0HjVGS3KdSqLo4/s640/hvac-1-638.jpg" width="640" /></span></a></div>
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<span lang="AR" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><span style="font-size: large;"><br /></span></span></div>
<div class="MsoNoSpacing" dir="RTL" style="direction: rtl; unicode-bidi: embed;">
<span style="font-size: x-large;"><span lang="AR" style="font-family: Arial, sans-serif;">تعريف </span><span dir="LTR">HVAC</span><span dir="RTL"></span><span dir="RTL"></span></span><span lang="AR" style="font-family: Arial, sans-serif;"><span style="font-size: x-large;"><span dir="RTL"></span><span dir="RTL"></span>؟</span><span style="font-size: large;"><o:p></o:p></span></span></div>
<div class="MsoNoSpacing" dir="RTL" style="direction: rtl; unicode-bidi: embed;">
<span style="font-size: large;"><span dir="LTR">HVAC</span><span dir="RTL"></span><span dir="RTL"></span><span lang="AR" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><span dir="RTL"></span><span dir="RTL"></span> هو
المجال الذي يهتم بالتدفئة والتهوية وتكييف الهواء في البيئة الداخلية للوفاء
بالراحة والمتطلبات الصحية لـ: - بناء الركاب ، - المعدات / العمليات</span><span dir="LTR"><o:p></o:p></span></span></div>
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<span style="font-size: large;"><span dir="RTL"></span><span dir="RTL"></span><span lang="AR-SA" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><span dir="RTL"></span><span dir="RTL"></span>:</span><span dir="LTR" style="font-family: 'Times New Roman', serif;">About Standards</span><span lang="AR-SA" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><o:p></o:p></span></span></div>
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<span dir="LTR"><span style="font-size: large;">ASHVE<o:p></o:p></span></span></div>
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<span dir="LTR"><span style="font-size: large;">ASHRAE<o:p></o:p></span></span></div>
<div class="MsoNoSpacing" dir="RTL" style="direction: rtl; unicode-bidi: embed;">
<span dir="LTR"><span style="font-size: large;">“ ANSI/ASHRAE standard 62.1 2007 ventilation for
acceptable indoor air quality “<o:p></o:p></span></span></div>
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<br /></div>
<div class="MsoNoSpacing" dir="RTL" style="direction: rtl; unicode-bidi: embed;">
<span lang="AR-SA" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><span style="font-size: x-large;">الانشطة :</span><span style="font-size: large;"><o:p></o:p></span></span></div>
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<span lang="AR" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><span style="font-size: large;">الحمل التبريدى<o:p></o:p></span></span></div>
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<span style="font-size: large;"><span lang="AR" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">أنواع وتطبيقات </span><span dir="LTR">AC</span><span lang="AR" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><o:p></o:p></span></span></div>
<div class="MsoNoSpacing" dir="RTL" style="direction: rtl; unicode-bidi: embed;">
<span lang="AR" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><span style="font-size: large;">تركيب مجاري الهواء والتصميم<o:p></o:p></span></span></div>
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<span lang="AR" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><span style="font-size: large;">ناشرات الهواء<o:p></o:p></span></span></div>
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<span lang="AR" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><span style="font-size: large;">التهوية<o:p></o:p></span></span></div>
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<span lang="AR" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><span style="font-size: large;">المراوح<o:p></o:p></span></span></div>
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<span lang="AR" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><span style="font-size: large;">تركيب مضخات وتصميم<o:p></o:p></span></span></div>
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<span style="font-size: large;"><span lang="AR" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">أنظمة المياه المبردة وأنظمة </span><span dir="LTR">VRF</span><span lang="AR" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><o:p></o:p></span></span></div>
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<span dir="RTL" lang="AR-EG" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR-EG; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><span style="font-size: x-large;">مقدمة :</span><span style="font-size: large;"><o:p></o:p></span></span></div>
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<span style="font-size: large;"><span dir="RTL" lang="AR" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">ما هي الحرارة؟</span><span dir="RTL" lang="AR-EG" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR-EG; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><o:p></o:p></span></span></div>
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<span style="font-size: large;"><span lang="AR" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">الحرارة هي شكل من أشكال الطاقة. كل كائن على
الأرض يحتوي على طاقة حرارية بكمية وكثافة.</span><span dir="LTR"><o:p></o:p></span></span></div>
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<span style="font-size: large;">Quantity Vs
Intensity<span dir="RTL"></span><span dir="RTL"></span><span dir="RTL" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><span dir="RTL"></span><span dir="RTL"></span> <span lang="AR">كثافة
مقابل شدة</span></span><o:p></o:p></span></div>
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<span style="font-size: large;">Measuring Heat
Quantity<span dir="RTL"></span><span dir="RTL"></span><span dir="RTL" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><span dir="RTL"></span><span dir="RTL"></span> <span lang="AR">قياس
كمية الحرارة<o:p></o:p></span></span></span></div>
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<span style="font-size: large;">One kcal is equal
to 4.19 kJ.<o:p></o:p></span></div>
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<span style="font-size: large;"><span dir="RTL"></span><span dir="RTL"></span><span style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><span dir="RTL"></span><span dir="RTL"></span> <span lang="AR">الحرارة تتدفق دائما من مادة أكثر
دفئا إلى مادة أكثر برودة.<o:p></o:p></span></span></span></div>
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<span lang="AR" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><span style="font-size: large;">ما يحدث هو أن الجزيئات المتحركة الأسرع تعطي
بعض طاقتها لبطء الشفاء المتحرك.<o:p></o:p></span></span></div>
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<span style="font-size: large;"><span lang="AR" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">لذلك ، فإن الجزيئات الأسرع تبطئ قليلاً ، أما
الخلايا الأبطأ فتتحرك أسرع قليلاً.</span><span dir="LTR"><o:p></o:p></span></span></div>
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<span style="font-family: Courier New, Courier, monospace; font-size: x-large;"><span lang="AR">مبادئ نقل الحرارة</span><span dir="LTR"></span><span dir="LTR"></span><span dir="LTR" lang="AR"><span dir="LTR"></span><span dir="LTR"></span> </span><span dir="LTR">Heat Transfer Principles</span></span><span lang="AR" style="font-family: Arial, sans-serif; font-size: large;"><o:p></o:p></span></div>
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<span style="font-size: large;"><span dir="LTR">Sensible VS Latent Heat</span><span lang="AR-SA" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><o:p></o:p></span></span></div>
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<span dir="LTR"><span style="font-size: large;">The rate of Heat Flow<o:p></o:p></span></span></div>
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<span style="font-size: large;"><span dir="LTR">TOR: One ton of refrigeration
produces the same cooling effect as the melting of 2000 lb of ice over a
24-hour period. </span><span dir="LTR"><o:p></o:p></span></span></div>
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<span dir="LTR"><span style="font-size: large;">Kilowatt:<o:p></o:p></span></span></div>
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<span dir="LTR"><span style="font-size: large;">Kilowatts describe the quantity of heat, in kJ, that flows
from one substance to another over a period of 1 second.<o:p></o:p></span></span></div>
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<span dir="LTR"><span style="font-size: large;">When <u>1 lb </u>of ice melts, it absorbs <u>144 Btu</u>.
Therefore, when 1 ton (<u>2000 lb</u>) of ice melts, it absorbs 288,000 Btu (<u>2000
x 144</u>). Consequently, <u>1 ton </u>of refrigeration absorbs <u>288,000 Btu </u>within
a <u>24-hour</u> period or <u>12,000
Btu/hr </u>(288,000/24).<o:p></o:p></span></span></div>
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<span style="font-size: large;"><b><span dir="LTR">Units of heat</span></b><b><span lang="AR-SA" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><o:p></o:p></span></b></span></div>
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<span style="font-size: large;"><b><span dir="LTR">Calorie [cal]...</span></b><span dir="LTR"><o:p></o:p></span></span></div>
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<span style="font-size: large;"><b><span dir="LTR">Kilocalorie [kcal]...</span></b><span dir="LTR"><o:p></o:p></span></span></div>
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<span style="font-size: large;"><b><span dir="LTR">Joule [J]...</span></b><span dir="LTR"><o:p></o:p></span></span></div>
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<span style="font-size: large;"><b><span dir="LTR">Kilojoules [kJ]...</span></b><span dir="LTR"><o:p></o:p></span></span></div>
<b><span style="font-family: Calibri, sans-serif; line-height: 115%;"><span style="font-size: large;">British thermal unit [Btu]...</span></span></b><div>
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<span style="font-size: large;"><span dir="LTR">The amount of heat required/removed to raise/lower the
temperature of <u>1lb</u> water <u>1°F</u>
is equal to <u>1Btu</u></span>.</span></div>
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<span style="font-size: large;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjLBLBYcFrV0WwO-cB9S6PnbXhLnt9GbGsL3Ss_bbvRPxr-G7oUFl7HtPnSdRS-qfYXkwzhSw_6XtJGbY8mxDy_Sann8PIU6jfxPL8s7yKDsScG2N_CG8s8D6ZMktNk6hwVRkpGzTm3Wt47/s1600/BE_L2_Chillers.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="400" data-original-width="600" height="266" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjLBLBYcFrV0WwO-cB9S6PnbXhLnt9GbGsL3Ss_bbvRPxr-G7oUFl7HtPnSdRS-qfYXkwzhSw_6XtJGbY8mxDy_Sann8PIU6jfxPL8s7yKDsScG2N_CG8s8D6ZMktNk6hwVRkpGzTm3Wt47/s400/BE_L2_Chillers.jpg" width="400" /></a></span></div>
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<span dir="RTL" lang="AR" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><span style="font-size: large;">ما هي "التبريد" و " تكييف الهواء"؟<o:p></o:p></span></span></div>
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<span style="font-size: large;"><span lang="AR" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;">يتم تعريف التبريد ... بأنه عملية تقليل والحفاظ
على درجة حرارة الفضاء أو المادة تحت درجة حرارة البيئة المحيطة.</span><span dir="LTR"><o:p></o:p></span></span></div>
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<span lang="AR" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><span style="font-size: large;">تكيف<o:p></o:p></span></span></div>
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<span lang="AR" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><span style="font-size: large;">يتم تعريف تكييف الهواء ... كعملية معالجة
الهواء وذلك للتحكم في نفس الوقت بالرطوبة والنظافة والتوزيع وكذلك درجة الحرارة
لتلبية متطلبات المساحة المكيفة.<o:p></o:p></span></span></div>
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<span lang="AR" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><span style="font-size: large;">تكييف الهواء هو جزء من التبريد بمعناه الواسع.</span></span><span dir="LTR"><o:p></o:p></span></div>
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<span lang="AR" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><span style="font-size: large;"><br /></span></span></div>
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<span lang="AR" style="font-family: "Arial","sans-serif"; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-language: AR; mso-bidi-theme-font: minor-bidi; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><span style="font-size: large;">ساعدونه بتعليقاتكم ونشركم لتعم الفائده</span></span></div>
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mohammed saifhttp://www.blogger.com/profile/04808794259319186322noreply@blogger.com0