Performance investigation of solar thermal collector with auxiliary heater for space heating

Abstract

In this paper, the performance of a solar thermal system with a focus on space heating was investigated. A 70 m² detached house was considered in the weather conditions of the city of Tehran, Iran. A thermosyphon solar water heater with a flat plate collector combined with an auxiliary electrical heater supplies the heating demand of the house. The proposed system was modeled and analyzed using TRNSYS software. In this regard, the TRNBuild module was employed for the building load calculation. The model has been simulated for one year of operation. The effects of the solar collector’s surface area and storage volume were assessed. The results show that for a solar collector with a 15 m² surface area, the solar fraction is 0.29 in January, during which the solar radiation is the lowest. Using solar collectors of 10 m² and 5 m² surface areas, the solar fraction falls to 0.23 and 0.14, respectively in January. Besides, two cases of 150 L and 300 L storage tanks are taken into account. Eventually, it is found that using a 15 m² solar collector and a 150 L storage tank can appropriately provide the building’s heating demand taking the thermal performance and economic aspects into consideration.

Keywords

space heating / solar water heater / thermosiphon / solar collector / TRNSYS software

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