Theoretical Study of HFO1336mzz(Z)/HFO1224yd(Z) Refrigeran t Mixtures for High-temperature Heat Pump

Background: The global energy consumption problem is becoming more serious, therefore, it is a hot trend to improve energy efficiency and choose environmentally friendly alternative working fluids. Objective: The main thermophysical parameters of the refrigerant mixture, which blended HCFO 1224yd(Z) and HFO1336mzz(Z) in the high-temperature heat pump cycle, were theoretically studied to replace HFC245fa. The theoretical cycle model of refrigerant mixtures of high-temperature heat pumps was established. Methods: In this paper, a theoretical cycle model of the mixed refrigerant high-temperature heat pump is established, and the cycle performance of the mixed refrigerant in the high-temperature heat pump system under different working conditions is compared. Results: It was found that HFO1336mzz(Z) could reduce the exhaust temperature of the compressor and increase the heat pump coefficient COPh, and HCFO1224yd(Z) could improve the problem of excessive suction specific volume in high-temperature heat pump systems. Conclusion: The result shows that the refrigerant mixture with 0.6/0.4 HCFO1224yd(Z)/HFO1336 mzz(Z) has the best cycle performance when the condensing temperature is 150 °C, and the cycle temperature rise ranges from 50 to 70°C.When the cycle temperature rise is 70°C, and the condensing temperature ranges from 110 °C to 150°C, the coefficient of performance value of the refrigerant mixture with 0.2/0.8 HCFO1224yd(Z)/HFO1336mzz(Z) reaches the maximum of 3.11.