Comparative Studies on the Efficiency of Solar Flat-Plate Collector and Evacuated Tube Collector

Solar collectors are the key components of solar thermal utilization. The comparative tests of solar flat-plate collector (SFPC) and heat pipe evacuated tube collector (HPETC) were done in this paper. The results show that during the low temperature difference range, the heat collecting efficiency of the flat-plate collector is about 2.3 times higher than the efficiency of the heat pipe evacuated tube collector and the heat loss of the flat-plate collector is about 3.2 times bigger than that of the heat pipe evacuated tube collector. Through the analysis, two measures are proposed to improve the efficiency of flat-plate collector and reduce the heat loss in order to make it more efficient in the solar heat pump system.