Performance Evaluation of Heat Pump System Using Non-Azeotropic Refrigerant Blends R1234ze/HCs

It is difficult for single refrigerant used in heat pump systems to achieve optimum results. However, according to the principle of complementary advantages, new refrigerant blends may perform much better than single refrigerant. Based on this idea, a thermodynamic model of a heat pump system was established under the nominal working conditions of heat pump water heater, and a comparative analysis was made between the refrigerant blends R1234ze/HCs and the corresponding pure refrigerant through the EES program. The results show that the R1234ze/R600 blend has the best ratio in a mass fraction of (20/80) and R1234ze/R600a in mass fraction of (40/60). The corresponding maximum heating coefficient of performance (COP) are 3.414 and 3.321, respectively. The COP of R1234ze/R290 blend, however, exhibits monotonicity with the change of mass fraction. The heating COP of the R1234ze/R600 (20/80) system is 2.7%, 17%, 0.09%, 16.3%, and 17.8% higher than that of the R1234ze/R600a (40/60), R1234ze, R290, R600, and R600a systems, respectively. The discharge temperature, condensing pressure and compression ratio of the R1234ze/R600 (20/80) system are 76.9 oC, 0.711 MPa and 6.32, respectively. The results are promising for the development of a prospective alternative working fluid.