Experimental study on the effect of refrigerant charging amount on the performance of CO2-air source heat pump system

The experimental study was carried out to explore the influence of refrigerant charging amount on the performance of the heat pump system. In the experiment, the amount of refrigerant to be charged was reflected by the pressure during refrigerant charging, and the pressure during refrigerant charging was changed to be 4.5 MPa, 5MPa, 5.5 MPa, 6 MPa and 6.5MPa, the ambient temperature was 25 degrees C, and the outlet water temperature of the heat pump was set to 65 degrees C Experimental research showed that the refrigerant filling quantity change would affect the CO2 air source heat pump system performance parameters, When the refrigerant charging amount increased, the system had the minimum power consumption and the maximum COP, and the system heat production increased gradually, and the time consuming decreased first and then increased. When the pressure of refrigerant was 6MPa, the CO2 air source heat pump system reached the best operating condition, with the minimum power consumption of 0.79kW and the maximum COP of 5.11.