Impact of the R407C and R134yf refrigerant charge on the performance of a new pure electric vehicle heat pump air conditioning system

The objective of this study was to investigate the impact of varying refrigerant charge levels of R407c and R134yf on the refrigeration performance of a vehicle heat pump air conditioning system. The study was conducted under high temperature conditions (45?C) to assess the influence of different refrigerant systems on refrigeration performance parameters. The results demonstrated that the optimal refrigerant charge level can be determined by analyzing the change in refrigeration performance parameters with varying charge levels. The results indicated that an increase in the refrigerant charge of R407c from 2.3 kg to 2.6 kg resulted in a maximum cooling capacity and COP of the system reaching 4.935 kW and 2.1, respectively. The optimal charging capacity of the system was determined to be 2.5 kg. Similarly, an increase in the refrigerant charging capacity of R134yf from 2.3 kg to 3.5 kg resulted in a maximum cooling capacity and COP of the system reaching 5.08 kW and 2.71, respectively. The optimal charging capacity of the system was determined to be 2.9 kg. The COP of the R134yf system is 0.61 higher than that of the R407c system. Furthermore, the energy saving of the R134yf system is more pronounced under extreme conditions.