Theoretical energy performance evaluation of different single stage vapour compression refrigeration configurations using R1234yf and R1234ze(E) as working fluids

• The energy performance of different single stage vapour compression configurations is compared.
• Working fluids considered are R1234yf and R1234ze(E) as alternatives for R134a.
• The most efficient configuration is the one which uses a turbine or an ejector as expansion device.
• Using an internal heat exchanger with a turbine/ejector could produce a reduction on the COP.
• On the other hand, an internal heat exchanger produces an increase on the cooling capacity.

R1234yf and R1234ze(E) have been proposed as alternatives for R134a in order to work with low GWP refrigerants, but this replacement results generally in a decrease of the performance. For this reason, it is interesting to explore ways to improve the system performance using these refrigerants. In this paper, a comparative study in terms of energy performance of different single stage vapour compression configurations using R1234yf and R1234ze(E) as working fluids has been carried out. The most efficient configuration is the one which uses an expander or an ejector as expansion device. On the other hand, using an internal heat exchanger in a cycle which replaces the expansion valve by an expander or an ejector could produce a detrimental effect on the COP. However, for all the configurations the introduction of an internal heat exchanger produces a significant increment on the cooling capacity.