R1234ze/HCs非共沸混合工质热泵系统循环性能分析

在热泵热水器名义工况下,本文建立了热泵系统循环热力学模型,利用EES程序对混合工质R1234ze/HCs及对应的纯工质热泵系统循环性能进行了对比分析。结果表明:R1234ze/R600在质量分数(20/80)和R1234ze/R600a在质量分数(40/60)存在最优配比,对应的最大制热COP_h分别为3. 41和3. 32,而R1234ze/R290则呈现单调下降趋势。R1234ze/R600(20/80)系统的制热COP_h比R1234ze/R600a(40/60)、R1234ze、R290、R600、R600a系统分别高2. 7%、17%、0. 09%、16. 3%和17. 8%,排气温度为76. 9℃,冷凝压力为0. 711 MPa,压比为6. 32,有望成为新型替代工质。

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.