Performance improvement potentials of low global warming potential refrigerants for intercity bus air conditioning system

Abstract

In this study, theoretical investigation of two evaporator ejector refrigeration system was carried out based on energy and exergy analysis using R134a and low global warming potential refrigerants (namely R1234yf and R1234ze(E)). In order to perform the analyses, a simulation model was developed and then the influence of different parameters on the COP, COP increase rate and exergy destructions were discussed for each refrigerant. The model was validated with experimental data for R134a and later used to predict the behavior with R1234yf and R1234ze(E). It was found that the highest exergy destruction occurs in the R1234yf system and the increase rate in the COP with respect to the conventional system by using ejector as an expansion device are 15% for R134a, about 17% for R1234yf and about 15% for R1234ze(E), respectively.