In this paper,the experimental setup of the direct expansion solar-assisted heat pump system was constructed.The experimental study was performed in spring and the results indicated that the COP ranged from 2.50 to 3.35 with 22-24 ℃ environment temperature and 700-1 000 W/m2 solar insolation.The influences of the parameters such as solar insolation,environment temperature and condenser temperature on the COP and the collector efficiency were thoroughly discussed through the analysis of typical results,based...