Improving the performance of evacuated tube heat pipe collectors using oil and foamed metals

Abstract

The objective of this research is to improve the heating capability of evacuated tubes that comprises heat pipes. Thermal oil is inserted in the evacuated tube in order to improve the rate of heat transfer, such that the mode of heat transfer from the inner surface of the evacuated tube to the heat pipe becomes convection via the oil, as well as conduction through the installed fin. The finned surface has been replaced by a foamed-copper. An experimental setup has been developed to study the influence of oil and foamed metals on the performance of evacuated tubes with heat pipes. It has been found that the bulb temperature as well as the heating efficiency of the evacuated tube heat pipe has increased in case of inserting oil in the evacuated tube and replacing the finned surface with foamed copper. Also, the thermal oil acts as a heat storage. Keywords: Evacuated tube, Heat pipe, Energy storage