In the light of low efficiency of photovoltaic power generation and the problems of air source heat pump applied in cold regions

a composite heat exchanger evaporator is developed and a new type of solar-air composite heat source heat pump hot water system is designed in this study

which is comprised of independent solar photovoltaic-thermal collector based on flat plate micro heat pipe and air source heat pump. The performance of heat pump hot water system is evaluated experimentally under different operating conditions

including water temperature of the tank

heating time of hot water

suction and discharge pressure

consumption of compressor power and heat pump coefficient of performance (COP)

etc. Experimental results show that at ambient temperature of 5℃

10℃ and 15℃

with 73 L hot water heated by heat pump and water temperature in the tank ranged from 15℃ to 50℃

the running time of composite heat source operation is shorter than that of separate air heat source operation

decreased by 5.14%

10.29% and 11.38%

respectively. COPs are increased by 5.99%

9.28% and 11.96%

respectively.