Experimental analysis of heat pipe solar collector with different L/d_i ratio of heat pipe

Abstract

Heat pipe solar collector has better collecting efficiency compared to the conventional collectors. In this paper, experiments on the effect of L/dratio of heat pipe on heat pipe solar collector are presented. Two solar collectors with different L/d_i have been designed and fabricated. A heat pipe with stainless steel wick replaces the transport tubes of the solar collector. Copper and stainless steel were used as container and wick material and methanol was used as working fluid of heat pipe. Heat pipes are designed to have heat transport factor of around 194 W and 260 W of thermal energy. Experiments were conducted during summer season with a collector tilt angle of 13^o to the horizontal. The collector with L/d_i ratio of 52.63 was found to be more efficient than the collector with L/d_i ratio of 58.82. This improved efficiency is due to increase in heat transport factor of heat pipe, which increase with decrease in L/d_i ratio.