Thermodynamic assessment of a condenser outlet split ejector-based high temperature heat pump cycle using various low GWP refrigerants

This paper presents a condenser outlet split ejector based cycle for high temperature heat pump. The thermodynamic behaviors of the cycle are investigated with energetic and exergetic methods. The condenser outlet split ejector-based cycle and ejector outlet split cycle are compared at various low GWP refrigerants suitable for high temperature heat pump applications, and results indicate that R600, R1224yd(Z), R1234ze(Z) and R1233zd(E) are proposed due to low GWP, high coefficient of performance (COP) and small compressor size. The condenser outlet split ejector-based cycle could provide dual-temperature evaporation with an ejector between two evaporators. In comparison with the basic heat pump cycle and the ejector outlet split cycle, the condenser outlet split-based cycle presents 14.1-17.5% and 5.4-11.9% higher COP, respectively. The ejector pressure lift ratio of the condenser outlet split ejector cycle is 6.5-12.5% higher than that in the ejector outlet split-based cycle. The exergy destruction of the evaporator can be effectively reduced by the dual-temperature evaporation in the condenser outlet split ejector-based cycle. The performance characteristics of the ejector outlet split cycle show its potential advantages in high-temperature heat pump applications. (C) 2019 Elsevier Ltd. All rights reserved.