شبیه‌‌سازی عددی استخر خورشیدی گرادیان نمک با استفاده از تابع تخمین شدت تابش خورشیدی به همراه اثر سایه دیوارها

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشکده مهندسی مکانیک، دانشگاه کاشان، کاشان، ایران

2 مجتمع دانشگاهی مکانیک، دانشگاه صنعتی مالک اشتر، اصفهان، ایران

چکیده

در این تحقیق تابع تخمین تابش خورشیدی بر اساس جرم هوا و آمار روزهای آفتابی و ابری جهت استفاده در مدل‌‌سازی عددی استخرهای خورشیدی معرفی شده است. استخرهای خورشیدی یکی از روش‌‌های جذب تابش خورشیدی و ذخیره‌سازی آن به صورت حرارت با دوره‌‌های ذخیره طولانی‌‌مدت می‌‌باشند. این تحقیق با کد شبیه‌‌سازی یک‌بعدی، نسبت به تحلیل عملکرد حرارتی استخرهای خورشیدی گرادیان نمک اقدام می‌‌نماید. در مدل‌‌سازی عددی با حذف فرضیات معمول، شرایط محیطی به صورت واقعی‌‌تر لحاظ شده‌‌اند. این شرایط دمای محیط متغیر برحسب روز و ساعت، تابعیت خواص محلول آب و نمک از دما و غلظت، متغیر شدت تابش بر حسب زاویه فراز خورشید و تاثیر سایه دیوارها در استخر بوده است. تحلیل گذرا انجام شده و شرایط روز و شب لحاظ شده‌‌اند. نوآوری روش مورد استفاده، مربوط به تخمین شدت تابش خورشیدی با استفاده از مفهوم جرم هوا و مقدار ابری‌بودن آسمان بوده است. رابطه‌‌ای نوین جهت محاسبه فاکتور پوشش ابر ارائه نموده، که از آمار روزهای ابری و نیمه ابری محل وقوع استخر استخراج گردیده و شدت تابش با میزان اندازه‌‌گیری‌شده تجربی مقایسه شده است. شدت تابش بدست‌آمده در مدل‌‌سازی عددی استخر خورشیدی مورد تحقیق با نتایج تجربی موجود تطابق خوبی دارد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Numerical simulation of salt gradient solar pond by employing the solar radiation estimating function considering wall-shading effects

نویسندگان [English]

  • Javad Amini Froshani 1
  • Ali Akbar Abbasian Arani 1
  • Mohammad Gandomkar 2
1 Mechanical Engineering Department, University of Kashan, Kashan, Iran
2 Faculty of Mechanics, Malek Ashtar University of Technology, Iran
چکیده [English]

In this study, a function for estimating solar radiation has been proposed using air mass effects and annual statistics of daylight conditions. A new relation for calculating the cloud cover factor has been provided by using the annual statistics of clear sky, partially cloudy, and overcast days. Estimated solar radiations have been compared with the measured experimental ones for two cities in Iran, and a good agreement has been observed. The proposed function can be used at places where the facilities and required instruments for solar radiation measurement are not available. As an illustration, the function has been used in numerical simulations of salt gradient solar ponds. One dimensional thermal analyses of the salt gradient solar ponds have been performed through an in-house code, which models the various parameters. Variation of environmental temperature, solar radiation intensity based on zenith angle of the sun, saline properties as a function of temperature and concentration, and wall-shading effects are among those parameters. A fair agreement has been observed between the results of the slat gradient solar pond numerical simulations and the experimentally measured temperatures, which shows the capability of the proposed function for estimating the solar radiation correctly.

کلیدواژه‌ها [English]

  • Solar radiation
  • Solar energy
  • Solar pond
  • Air mass
  • Cloud cover factor
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