Experimental research on heating performance of solar energy coupled with water source heat pump system

Abstract This paper establishes an experimental platform for a solar energy coupled water source heat pump system, tests the performance curve of the heat pump, and analyzes the system’s operational performance. The experimental study shows that under the conditions of compressor power (0.7 kW-2.2 kW) and evaporator inlet water temperature (14°C-21°C), for every 1°C increase in the heat pump inlet temperature, the Coefficient of Performance (COP) improves by an average of 0.07, and the heating capacity increases by an average of 0.15 kW; for every 0.4 kW increase in compressor power, the COP decreases by about 0.7, and the heating capacity increases by an average of 0.47 kW. The inlet and outlet temperatures of each component of the water source heat pump are related to the evaporator inlet water temperature. As the evaporator inlet water temperature rises, the inlet and outlet temperatures of all components increase, and vice versa. A standalone water source heat pump heating system, with a compressor power of 1 kW, has a COP of only 3.82, gradually decreasing as the power increases. The minimum COP of the solar-coupled water source heat pump system is 3.86, and it gradually increases with the intensity of solar radiation. This composite system not only improves the overall energy efficiency of the system but also avoids the high-power consumption drawbacks of traditional heat pumps. It can serve as one of the optional heating solutions for rural small-area residences.