Numerical investigation on thermodynamic performance of CO2-based mixed refrigerants applied in transcritical system

The CO2-based mixed refrigerants R744/R152a and R744/R161 are proposed to enhance the thermodynamic performance of pure CO2 refrigerant. The basic physical properties of the three refrigerants were analyzed, and the thermodynamic performance of refrigerants with different CO2 ratios are compared. The results present that the optimized ratios of the new refrigerants are R744/R152a: 0.875/0.125, R744/R161: 0.850/0.150, based on which the coefficient of performance (COP), heating and cooling capacity of the optimized refrigerants increase significantly, which are up to 90% of R134a, and the exhaust pressure reduces by 1.6–1.8 MPa compared with that of pure CO2.