A Screening of Low-GWP Refrigerant for Ejector Refrigeration

Ejector refrigeration is a promising technology to reduce primary energy consumption for building cooling. Unfortunately, a change in the design criteria (i.e., geometry, working fluid, operating conditions) influences the system performance owing to variations in the local fluid dynamic phenomena at the “local-scale”. For this reason, a general agreement on ejector performance is far from being reached. In addition, a general assessment of ejector performance is even more challenging when considering the recent regulations concerning the working fluids, which are going to phase-out most of the refrigerants commonly used in refrigeration and air conditioning systems. Despite there are different options to replace them, no refrigerant has yet imposed. This paper contributes to the discussion on the screening of working fluids, using a previously-validated lumped parameter model. The modelling approach has been applied to sub-critic ejector refrigeration systems and some alternatives to high GWP refrigerants are considered. The influence of the generator, the evaporator and the condenser temperatures over the ejector performance, for the different working fluids, have been presented and commented. The results are comments in terms of entrainment ratio and coefficient of performance, to provide indications and guidelines for refrigerant selection in prospective ejector refrigeration systems