Comparison of Performance and Efficiency of Different Refrigerants at High Load Conditions and their Impact on CO2eq Emissions

For battery-electric vehicles (BEVs), the climate control and the driving range are crucial criteria in the ongoing electrification of automobiles in Europe towards the targeted carbon neutrality of the automotive industry. The thermal management system makes an important contribution to the energy efficiency and the cabin comfort of the vehicle. In addition to the system architecture, the refrigerant is crucial to achieve high cooling and heating performance while maintaining high efficiency and thus low energy consumption. Due to the high efficiency requirements for the vehicle, future system architectures will largely be heat pump systems.

The alternative refrigerant R-474A based on the molecule R-1132(E) achieved top performance for both parameters in various system and vehicle tests. An own-built energy efficiency tool was used to determine the possible energy reduction of R-474A in comparison to refrigerant alternatives that can be translated in a CO2 reduction of the thermal management as part of the overall vehicle CO2 footprint reduction.

The results served as the basis for an efficiency study comparing the refrigerant R-474A against systems with pure R-1234yf and R-744 in a BEV in both cooling mode (AC mode) and heating mode (HP mode). The analysis was carried out with a focus on the performance and efficiency of thermal management under different climatic conditions and considering different driving cycles. The results of the most recent investigations and the study will be presented in this paper.