تعیین فاصله مناسب بین صفحه جاذب و پوشش یک لایه در جمع‌کننده‌های خورشیدی صفحه تخت به روش عددی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 گروه مهندسی ماشین های کشاورزی و مکانیزاسیون، دانشگاه علوم کشاورزی و منابع طبیعی خوزستان، ملاثانی، ایران

2 گروه مهندسی ماشینهای کشاورزی و مکانیازسیون-دانشگاه علوم کشاورزی و منابع طبیعی خوزستان-ملاثانی

چکیده

بیشترین اتلاف انرژی در جمع­کننده­های صفحه تخت مربوط به افت گرمایی از بالاست. متغیرهای دمای سطح جاذب، دمای محیط، سرعت وزش باد، فاصله بین صفحه جاذب تا پوشش، طول و زاویه جمع­کننده بر این افت تأثیرگذار هستند. در این پژوهش با در نظر گرفتن اطلاعات بلند مدت هواشناسی و روابط توسعه داده شده در پژوهش­های گذشته برای افت از بالا در جمع­کننده­های خورشیدی صفحه تخت شامل افت­های همرفت، هدایتی و تابشی، محاسبات در قالب کدهای فرترن انجام شد. نتایج نشان داد مقدار مناسب فاصله بین صفحه جاذب و پوشش تک لایه در محدوده 11 تا 38 میلی­متر برای چند شهر کشور است. همچنین تحلیل حساسیت متغیرها بر افت از بالا نشان داد، ترتیب آنها از بیشترین به کمترین عبارت است از: سرعت وزش باد، فاصله پوشش تا صفحه جاذب، زاویه شیب جمع­کننده، طول جمع­کننده، دمای صفحه جاذب و دمای محیط.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Determination of the Proper Distance between the Absorber Plate and One-layer Cover in Flat-plate Solar Collectors Using Numerical Method

نویسندگان [English]

  • Rouhollah Farhadi 1
  • Morteza Taki 2
1 Department of Agricultural Machinery and Mechanization, Agricultural Sciences and Natural Resources University of Khuzestan, Mollasani, Iran
2 Department of agricultural machinery and mechanization- Agricultural Sciences and Natural Resources University of Khuzestan-Mollasani
چکیده [English]

The Maximum energy loss in flat-plate solar collectors is due to top heat loss. The variables of absorber plate temperature, ambient temperature, wind speed, the distance between the absorber plate and the cover, collector length, and tilt angle are effective. In this research, considering the long-term meteorological data and developed relations for the top loss in flat-plate solar collectors in previous researches, including convection, conduction and radiation losses, calculations were performed in the form of Fortran codes. Results showed that the proper value for the distance between the absorber plate and one-layer cover has the range of 11 to 38 mm for some cities of the country. In addition, the sensitivity analysis of the top loss showed that the order of variables from maximum to minimum is wind speed, the distance between the absorber plate and the cover, collector tilt angle, collector length, absorbent plate temperature and ambient temperature.

کلیدواژه‌ها [English]

  • Air gap
  • Renewable Energies
  • Sensitivity analysis
  • shadow
  • Top loss
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