In this paper, the feasibility of two low global warming potential
refrigerants R513A and R1234yf as alternatives to R134a was tested in an
automotive air conditioning system in winter. The test results showed that
the heating capacities of R513A and R1234yf were 2% and 4% lower than that
of R134a, and their COP were 3-9% and 6-19% lower than that of R134a,
respectively. It revealed that R513A can be used as a transition product to
replace R134a, and R1234yf required further improvements to improve the
energy efficiency.