Experimental evaluation of an indirect air heating system employing heat pipe solar collectors

In this paper, a solar air heating system employing heat pipe solar collector was studied and analyzed experimentally. The proposed system was constructed and experimented under climatic conditions of Sannandaj, (Latitude 35, Longitude 45 and Altitude 1450 m), on the last days of August from 9:00 AM to 6:00 PM. It was resulted that the maximum collector outlet temperature is 64.3 °C. Collector inlet and outlet and storage tank temperature changes are also presented. Some fluctuations were observed, which was the result of drawn out hot water of the storage tank for air heating section. In the morning, there is essential need to back up system, but, after 14:00 PM, the solar system becomes indipendent of it. It was also resulted that outlet air temperature is completely a function of solar radiation. The maximum outlet air temperature is 48.3 °C which occurs at 12:50. Because of having a higher temperature difference between hot water and inlet air, the performance of the system is better before noon. The heat exchanger effectiveness increases as time passes. After noon, the effectiveness slope becomes descending

Keywords:

solar air heating , heat pipe solar collector , Sannandaj