A comprehensive assessment of refrigerants for cabin heating and cooling on electric vehicles

With more and more stringent environmental requirements that go into effect, the automotive industry is moving away from R134a. All major automotive manufacturers are considering next generation refrigerants, but there is still no agreement on the final choice. As for electric vehicles, the choice of refrigerant to replace R134a is even more complex, since a refrigerant's heating capacity and efficiency should be considered with the gradual adoption of heat pump technology for cabin heating. In order to help select the best refrigerant for electric vehicle HVAC systems, in this paper a comprehensive assessment has been conducted for seven refrigerants: R134a, R152a, R1234yf, R290, R410A, R32, and R744 (CO2). TEWI method is used for evaluating the total global warming impact for each refrigerant, in which both the cabin cooling and heating are considered in the calculation of indirect emission from energy consumption. For cabin heating, heat pump is used to its maximal available capacity, whereas PTC heater is used for supplemental heating. TEWI assessment results show that R290 refrigerant generates the lowest amount of equivalent CO2 emission whereas R744 gives off the highest amount. When considering comprehensively safety, heating capacity and global warming impact, R32 is found to be a very promising heat pump refrigerant.