Carbon Mitigation Potential of the New Energy Bus Thermal Management Systems with the International Ban of Hydrofluorocarbons

Abstract

To address carbon emissions from transportation, an integrated thermal management system for electric buses using natural refrigerant CO2 (CO2-TMS) was developed. Based on the China Heavy-Duty Commercial Vehicle Test Cycle (CHTC-B), its thermodynamic performance and environmental benefits were evaluated against conventional R407C and Basic-CO2 systems. Key findings include: a. Heating: At −30 °C, the COP of Basic-CO2 was 2.11 times that of R407C. With 16 kW of recovered waste heat, the COP was further improved by 17.65%. The R407C system relied on PTC heating (91% contribution), with a COP only 47.4% of Basic-CO2.b. Cooling: At 36 °C, R407C showed 21.5% higher COP than Basic-CO2, but CO2-TMS improved COP by 3.0% via 3 kW of motor/battery waste heat dissipation.c. Driving range: CO2-TMS extended range by 27.0% at −30 °C and 9.6% at 28 °C compared to R407C.d.LCCP: Based on an LCCP model incorporating city-level climate data nationwide, the CO2-TMS achieved a total LCCP reduction of 89,370 kt (2137% of Basic-CO2) and an average LCCP reduction rate of 7.68%, far above Basic-CO2 (0.61%)..This study offers quantitative support for low-carbon thermal management in new energy buses.

Keywords: Electric bus, Waste heat recovery, CO2 thermal management system, Driving range, Carbon emission