بررسی عددی تأثیر سرعت و مکان قرارگیری فن‌سقفی بر آسایش‌حرارتی و کاهش مصرف انرژی در ساختمان‌های اداری

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشکده مهندسی مکانیک، دانشگاه کاشان، کاشان، ایران

چکیده

هدف از مطالعه حاضر بررسی عددی تأثیر سرعت و مکان قرارگیری فن سقفی بر پارامترهای آسایش حرارتی و مصرف انرژی در دو نمونه اتاق اداری متفاوت با ابعاد مشخص در فصل زمستان با سیستم گرمایش متمرکز است. در تمامی مدل ها رژیم جریان آشفته بوده و از مدل k-ε برای مد لسازی آشفتگی استفاده شده است. بر اساس نتایج، استفاده از فن سقفی، بدون درنظرگرفتن مکان آن در یک ارتفاع مشخص، باعث کاهش مصرف انرژی می شود. با روشن کردن فن و افزایش سرعت عمودی آن، وضعیت شاخص های میانگین آراء افراد نسبت به شرایط گرمایی محیط (PMV   ) و درصد نارضایتی افراد نسبت به شرایط گرمایی محیط (  PPD  ) بهبود می یابد؛ اما از جایی به بعد کارکرد فن به سمت خنک کاری پیش رفته و دیگر برای سیستم گرمایش مناسب نیست. همچنین نتایج نشان می دهند که شاخص های آسایش حرارتی PMV و PPD تنها شرط لازم برای تأمین آسایش حرارتی انسان نیستند و شرط کافی بررسی جداگانه پارامترهای پنج گانه تشکیل دهنده شرایط آسایش حرارتی است. در پایان حالت های CF.A با p(x)=1m ، سرعت عمودی هوای فن 0/2m/s و دمای رادیاتور 51°C و CF.B.1 با m p(x)=2.5m ، سرعت عمودی هوای فن 0/27m/s و دمای رادیاتور 37°C ، با تأمین شرایط آسایش حرارتی و کاهش میزان مصرف انرژی به ترتیب در حدود 37 % و 48 % ، به عنوان مدل های بهینه در کار حاضر معرفی شده است.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Numerical Study of the Effects of Speed and Place of Ceiling Fans on Thermal Comfort and Reducing Energy in Office Buildings

نویسندگان [English]

  • G.A. Sheikhzadeh
  • S. Sadripour
  • M. Mollamahdi
Mechanical Engineering Department, University of Kashan, Kashan, Iran
چکیده [English]

The main aim of the present study is to investigate the effects of speed and place of ceiling fans on thermal comfort parameters (predicted mean vote and predicted percentage of dissatisfied) and energy expenses in two different office rooms with a certain geometry in winter using district heating system. In all of the models, the regime of a flow is turbulent and governing equations are solved by finite volume method and SIMPLE algorithm. Based on the results, using ceiling fans in winter (heating system) has a considerable influence on the improvement of buildings thermal comfort and reducing consumption of energy. By using ceiling fans the effective temperature of room increases and therefore radiator energy consumption decreases. Furthermore, the results show that the location of ceiling fan does not have any effect on room effective temperature and residents’ thermal comfort. According to the results, predicted mean vote and predicted percentage of dissatisfied parameters improve by turning ceiling fans on and increasing fan normal air velocity. But, the operation of fan leads to cooling system after a certain velocity and it is not acceptable for the heating system. Finally, the CF.A case with p(x)=1.0 m, V=0.2 m/s and Tradiator=51oC, and CF.B.1 case with p(x)=2.5 m, V=0.27 m/s and Tradiator=37oC, by providing thermal comfort conditions and reducing consumption of energy about 58% and 73%, respectively are reported as optimal cases. 

کلیدواژه‌ها [English]

  • Place of ceiling fan
  • heat transfer
  • Turbulent flow
  • Thermal comfort
  • Reducing consumption of energy

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نشریه مهندسی مکانیک امیرکبیر
دوره 50، شماره 2
خرداد و تیر 1397
صفحه 309-326

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