Performance of virtually non-flammable azeotropic HFO1234yf/HFC134a mixture for HFC134a applications

In this study, ‘drop-in’ performance of HFC134a, HFO1234yf and HFO1234yf/HFC134a mixture at three compositions of 5%, 10%, and 15% HFC134a is measured in a heat pump bench tester under summer and winter conditions. Test results show that the COP, capacity, discharge temperature of HFO1234yf and HFO1234yf/HFC134a mixture are similar to those of HFC134a. For HFO1234yf/HFC134a mixture, flammability decreases as more HFC134a is added and at compositions of more than 10% of HFC134a, the mixture becomes non-flammable. The amount of charge for HFO1234yf and HFO1234yf/HFC134a mixture is up to 11% lower than that of HFC134a. Since HFO1234yf/HFC134a mixture with 10–11% HFC134a is virtually non-flammable and azeotropic and has no ODP and GWP of less than 150 meeting the requirement of European mobile air-conditioner directive, it can be used as an environmentally friendly solution for various HFC134a applications including mobile air-conditioners with minor modifications.