Energetic performance and driving range comparison among CO₂ and R290 in the new energy vehicle thermal management systems

To address the pressing issues posed by the phase-out of high-GWP hydrofluorocarbon (HFC) refrigerants in electric vehicle (EV) thermal management systems (TMS) and the “driving range anxiety” due to excessive heating energy consumption in winter conditions, this study focused on natural refrigerants CO₂ and R290 as alternatives to HFC for EVs’ TMS. Firstly, high-fidelity dynamic TMS models incorporating three refrigerants (R134a, CO₂, and R290) were developed based on a multi-physics simulation platform. Then, the thermal management performances of TMSs using different refrigerants under CLTC driving cycles were systematically evaluated by performance metrics including coefficient of performance (COP), thermal management energy consumption factor (TMEF), and driving range (DR). Furthermore, seasonal variations in cooling/heating performance and annual comprehensive performance were analyzed. The results demonstrated that: The CO₂ TMS performed the worst in cooling modes, while the R290 TMS showed smaller gaps compared to the R134a TMS, with the most severe attenuation. However, the CO₂ TMS had the leading heating performance, particularly in severe cold conditions, while the R290 TMS performed better than the R134a TMS at temperatures below −12 °C. Therefore, CO₂ significantly reduced DR anxiety in winter through excellent heating performance, and R290 provided better energy efficiency in cooling conditions. In combination with annual average COP, TMEF, and DR results, CO₂ was suitable for cold regions, and R290 was more suitable for hot regions and hot summer/winter regions. These analyses provide critical guidance for refrigerant substitution initiatives and served as a significant reference for advancing high-efficiency, low-carbon thermal management technologies in EVs.