Simulation of diffusion of combustible refrigerants R1234yf and R290 leakage in automotive air conditioning.

• Conducted a numerical study on the leakage of R1234yf and R290 into the passenger compartment of electric vehicles. • Evaluated and compared the volume concentrations of R1234yf and R290 with experimental data. • Discussed the volume concentration distributions of R1234yf and R290 within the passenger compartment in detail. • Analyzed and compared the highest volume concentrations of R1234yf and R290 against their respective LFL. Electric vehicles that utilize a heat pump system have a refrigerant charge increase of at least 400 g compared to traditional fuel vehicle air conditioning systems. If combustible refrigerants are used, the risk of combustion increases when the refrigerant leaks and spreads to the passenger compartment. This paper dynamically monitored the volume concentrations of combustible refrigerants R1234yf and R290 as they leaked and entered the passenger compartment accompanied by air supply by numerical simulation. The results indicated that refrigerants are more prone to accumulate in the rear row than in the front. After a leak, the average volume concentration of R1234yf at the four air outlets was 1.58 %, and 3.36 % for R290. at the breathing points of four passengers, the average volume concentration was 0.99 % for R1234yf and 2.39 % for R290. Near the feet of the passengers, the average volume concentration was 0.95 % for R1234yf and 2.27 % for R290. The highest volume concentration of R1234yf in the passenger compartment was below its LFL, whereas all monitoring points for R290 exceeded its LFL. Compared to experimental data, the difference in maximum refrigerant volume concentration was approximately 1.2 %. [ABSTRACT FROM AUTHOR]