Thermodynamic performance of heat pump with R1234ze(E)/R1336mzz(E) binary refrigerant

• Published in: Applied thermal engineering 2023-07, Vol.230, p.120795, Article 120795
• Main Authors: Hu, Hemin, Wang, Tao, Jiang, Yuyan, Bi, Chao, Zhang, Bing, Fan, Siyi, Li, Jianchao, An, Siyuan, Bai, Xiusen, Guo, Cong
• Format: Article
• Language: English
• Subjects: Binary refrigerant; Heat pump; R1234ze(E) / R1336mzz; Temperature glide; Thermodynamic performance
• ISSN: 1359-4311
• DOI: 10.1016/j.applthermaleng.2023.120795

•Configurations under different heat sources and heat targets are constructed.•R1234ze(E)(0.3)/R1336mzz(E)(0.7) is recommended, for heat pumps.•COP and high quality output heat respectively increase by 67.25% and 335.16%.•COP of hot water heat pump with binary refrigerant has greatly improved. In order to solve the temperature mismatch issue of cold and hot fluids in evaporation and condensation processes for heat pump system, binary refrigerant R1234ze(E)/R1336mzz is recommended in the present research due to its large temperature glide. Through theoretical analysis, multiple configurations under conditions of three different temperature heat sources (70/50 °C, 60/40 °C and 50/30 °C) and two different heat targets (steam above 100 °C and hot water with 70 °C) are constructed adopted Ebsilon code. The optimum mass proportion is obtained as 0.3/0.7 for R1234ze(E)/R1336mzz(E), because of its maximum temperature glide (can reach 21.52 °C) and excellent thermal performance (large COP, ECOP and exergy efficiency). COP of steam high temperature heat pump with R1234ze(E)(0.3)/R1336mzz(E)(0.7) binary refrigerant and the ratio of transferred heat of 110 °C condenser to all output heat (containing 110 °C and 100 °C steam intercooler and condensers) respectively increase up to 67.25% and 335.16% under some certain conditions, compared with that with pure R1336mzz(E). COP of hot water heat pump with R1234ze(E)(0.3)/R1336mzz(E)(0.7) binary refrigerant are respectively 10.31 and 6.89 under 60/40 °C and 50/30 °C heat source conditions, which greatly increases compared with that of heat pump with pure R1234ze(E) (6.67 and 5.03) and R1336mzz(E) (6.74 and 4.54). The present research may lay a foundation for binary refrigerant adoption to replace the scheme of multi-stage evaporator or multi-stage condenser, which could reduce the irreversible loss of phase change equipment and improve thermodynamic performance of heat pumps.