Study on Economized Vapor Injection Heat Pump System Using Refrigerant R32

The refrigerant R32 is considered as a potential alternative refrigerant of R410A because of its low global warming potential (GWP) and the basic thermodynamic parameters. It can effectively improve the heating efficiency and reduce the discharge temperature of the compressor to use the economized vapor injection (EVI) refrigeration system. In this paper, the performance of the EVI heat pump system using refrigerant R32 is investigated experimentally under the conditions of the evaporating temperature ranged from -2 degrees C to -15 degrees C. The experimental results indicate that the injection ratio, heat capacity and power consumption of the EVI heat pump system increase with the injection pressure. The maximum injection ratio of the EVI heat pump system is about 33% under the evaporating temperature of -15 degrees C. For the EVI heat pump system, the system COP achieves the maximum value as the injection pressure ranges from 1.48 MPa to 1.54 MPa when the evaporating temperature is lower than -6 degrees C. The discharge temperature of the EVI heat pump system drops by 11 degrees C under the evaporating temperature of -15 degrees C. As the evaporating temperature is below -6 degrees C, the COP of the EVI heat pump system is higher than that of the traditional single stage heat pump.