AN EXPERIMENTAL STUDY ON PERFORMANCE IMPROVEMENT FOR AN AIR SOURCE HEAT PUMP BY ALTERNATE DEFROSTING OF OUTDOOR HEAT EXCHANGER

Abstract

For a space heating air source heat pump (ASHP) in the condition of low temperature and high humidity, frost on the surface of heat exchanger becomes the major cause decreasing heating surface area and thus the performance of heat pump. In this study, we showed a method of delaying the implantation of frost using alternate defrost control. First, we acquired the performance data for conventional periodic reversed-cycle defrosting with a 5RT heat pump. After the experiment, the heat pump was modified to verify the effects of newly introduced alternate defrosting and compared with the conventional periodic reverse cycled method. It was found that heating coefficient of performance (COP) of heat pump using newly proposed alternate defrost method was about 17% higher than conventional heat pump using periodic reverse cycled defrosting.