بهینه یابی انرژی گنبدهای آب انبارها؛ نمونه موردی: گنبدهای شهر قزوین (مقاله علمی وزارت علوم)
درجه علمی: نشریه علمی (وزارت علوم)
آرشیو
چکیده
آب انبارها علاوه بر مناطق گرم و خشک، در مناطق سرد کشورمان نیز مورد استفاده عموم قرار می گرفته است. یکی از اصلی ترین عنصر آب انبارها پوشش مخزن آن هاست، که از طاق های آجری گوناگون مانند آهنگ، کلنبو با خیز و فرم های متفاوت ساخته شده است. هدف از این پژوهش شناخت میزان دریافت تابش خورشید در سطوح و جریان حرارت در داخل گنبد آب انبارهای قزوین می باشد که منجر به شناخت بهینه ترین فرم پوشش مخزن آب انبار در بین نمونه های مطالعه شده می گردد. برای انجام این تحقیق چهار نمونه از آب انبارها با ساختار متفاوت گنبد در شهر قزوین انتخاب، سپس گنبدها در نرم افزار Revit 2016 مدلسازی شد و میزان دریافت تابش خورشید گنبدها در سردترین روز سال و در ساعات 13، 14و 16 با استفاده از پلاگین های Honeybee & Ladybug با موتور انرژی پلاس مشخص گردید. برای اعتبارسنجی با استفاده از نرم افزار COMSOL تحلیل جریان هوای یکسان CFD در گنبدهای خیز بلند و کم انجام شد. نتایج آنالیزها نشان دادند که میزان دریافت تابش در سطوح گنبد آب انبارها متفاوت است و در گنبدهای خیز کم و سطح تماس زیاد نسبت به تابش خورشید، عملکرد دریافت حرارت نسبت به گنبدهای خیز بلند، بیشتر است. زیرا این گنبدها سطوح بیشتری در معرض تابش خورشید قرار می دهند. در تحلیل جریان CFD در هنگام ظهر و گرمای شدید روز، در قسمت بالای گنبد خیز بلند گردابه ی گرما ایجاد می گردد که از گرم شدن بیش از حد داخل گنبد جلوگیری می نماید. بنابرین مناسب ترین گنبد برای آب انبارهای اقلیم سرد قزوین، گنبدهای خیز کم می باشند.Energy optimization of the Ab-Anbar domes; Case study: Domes of Qazvin city
Extended Background and Objectives: Traditionally, the public has used Ab-Anbars (water reservoirs) in hot and dry areas and also in cold regions of Iran. One of the main elements of Ab-Anbar is the reservoir coverage (reservoir lining), which is made of various brick vaults such as barrel and colombo vaults with different rises and forms. Due to the dry weather in most parts of Iran and insufficient rainfall in more than six months of the year in most places, which has resulted in the seasonality of rivers and the lack of access to water, various arrangements have been established for freshwater supply in dry seasons. The construction of the Ab-Anbar (water reservoir and cistern) is one of the innovative ways to supply drinking water. In this regard, the Ab-Anbar, as its name implies, is used to store water in rainy seasons to be used for the rest of the year. The main structure of the Ab-Anbar consists of an underground storage tank and a dome to cover it. In some areas in Iran, a wind catcher is added to this structure to keep the water cool in summer. The construction material used for Ab-Anbars was a special mortar called Sarooj, which was made of sand, clay, lime, goat hair, egg whites, and ash in specific proportions, depending on the location and climate of the place. Some Ab-Anbars had rectangular storage tanks, and some tanks had a cylindrical shape. This study aims to determine the amount of solar radiation received on the surfaces and heat flow inside the Ab-Anbar domes of Qazvin, which leads to recognizing the most optimal form of reservoir coverage for Ab-Anbars among the studied samples. Methods: The data, including dry and humid temperature, air, radiation, and current radiation situation of Qazvin city weather station, were prepared over a ten-year period (1996-2006). The library documents also provided the map of the Ab-Anbar domes. In order to conduct the research, four samples of Ab-Anbars with different dome structures in Qazvin city were selected. After that, the domes were modeled in Revit 2016, and the amount of solar radiation received by the domes on the hottest day of the year, at 14, 16, and 18 o’clock, were determined using honeybee & ladybug plugins with Energy plus Engine. COMSOL software, and the CFD airflow analysis, were performed for validation in high-rise and low-rise domes. Findings: The results of the analyses showed that low-rise domes with large surface contact receive more heat than high-rise domes with a small surface contact, and the area of the domes is effective in receiving the sun radiation. Sardar Kouchak (Little Commander) dome, a low-rise dome, is approximately exposed to its total surfaces and solar heat by 84.3% at 14 o’clock. In comparison, the high-rise dome next to the Grand Mosque is exposed by 52.5% at 14 o’clock. The low-rise dome is exposed by 74.7%, while the high-rise dome is exposed by 53.5% at 16 o’clock. Finally, the low-rise dome is exposed by 62.4%, and the high-rise dome is exposed by 43.2% at 18 o’clock. Therefore, low-rise domes in the cold climate are more efficient in receiving solar radiation than high-rise ones. Conclusion: The airflow inside the domes was graphically performed for validation using CFD analysis on a hot day. The results are consistent with the outputs from honeybee & ladybug plugins. Low-rise domes can retain more heat than high-rise domes, and the vortex of hot air created in low-rise domes is less than in high-rise domes, which leads to more heat gain inside the dome. Therefore, the most suitable dome for Ab-Anbar in the cold climate of Qazvin are low-rise domes.
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