Theoretical research on the performance of the transcritical ejector refrigeration cycle with various refrigerants

• A thermodynamic model is used to simulate the ejector with real properties.
• The performance of the TERC with various refrigerants is compared.
• The environment-friendly working fluid of R1270 shows the most proper one.
• The COP of the transcritical cycle is higher than that of the subcritical cycle.

The transcritical ejector refrigeration cycle (TERC), which has shown an attractive alternative to the ejector refrigeration systems, can better match large variable-temperature heat sources and yields higher COP. In this paper, in order to find a proper working fluid for the TERC, the performance of the TERC with CO2 and various working fluids with low critical temperatures including R1270, R32, R143a, R125 and R115 are studied and compared. A thermodynamic model for ejector is set up to simulate the ejector by introducing the real properties of refrigerants. The results indicate that R1270 has the highest COP at the same heat source condition and medium working pressures, and is one of environment-friendly working fluids, hence R1270 is the most proper one. The COP of the transcritical cycle is higher than that of the subcritical cycle, and The effective performance coefficient COPm of the transcritical cycle is also better. When the heater outlet temperature is increased, its system COPm improves, but its system COP almost does not change.