Life cycle climate performance evaluation (LCCP) of electric vehicle heat pumps using low-GWP refrigerants towards China's carbon neutrality

Abstract

The environmental-friendly heat pump with low global warming potential (GWP), such as R1234yf, CO2, R290, and several potentially promising refrigerant mixtures, is increasingly essential for the electric vehicle (EV) to save energy consumption and extend the driving range. It is beneficial to achieve carbon neutrality by reducing both direct and indirect carbon emissions. Previously, the life cycle climate performance (LCCP) was a widely accepted metric to evaluate the carbon footprint of mobile air conditioning systems “from cradle to grave” for the internal combustion engine vehicle (ICEV), however, such LCCP analyses about EV heat pumps can hardly be found. To facilitate the EV industry and policymakers' better understanding of the environmental impacts of those low-GWP refrigerants, this study provided a comprehensive LCCP analysis for the EV heat pumps based on the system bench test results, local climates, local power supply characteristics, real-world driving patterns, vehicle cabin thermal sensation, and climate control load. Five low-GWP refrigerants, i.e., R1234yf, CO2, R290, binary blends of CO2 and R41 (with GWP values of 49), M2(R410A substitute with GWP values of 137), were compared against R134a and R410A in 31 provinces of mainland China. We also considered the impacts of electric vehicle adoption rates and the carbon intensity of electricity from 2020 to 2060. Results show that the total life-cycle emissions per vehicle are highly related to climate conditions in different provinces, while R290 shows the lowest emission on the national average. The national mean life-cycle emissions per vehicle are projected to decrease 14% by 2030 and 45.4% by 2060 under the current technological trajectory of electricity generation. By using low-GWP heat pump systems in EVs, the cumulative emissions counting all vehicles can be saved up to 1450 Mt. CO2e from 2020 to 2060.