Influence of subcooling in R-449A supermarket refrigeration system and screening of refrigerant mixtures for its energetic and environmental improvement

Abstract

Current demands of the cooling sector are focused on using refrigerants with a low Global Warming Potential (GWP) and increasing energy efficiency in vapour compression installations. The main objectives of this paperwork arise from these needs, in which the use of subcooling in an R-449A commercial refrigeration system is evaluated. In addition, eco-friendly alternative refrigerants are proposed and studied. Firstly, the effect of an integrated type of subcooling is semi-empirically analysed with Engineering Equation Solver (EES). Then, the refrigeration system’s operation is simulated using low-GWP alternative refrigerants, R-454C and R-290, which have been scarcely studied in commercial refrigeration systems due to their safety classification. Moreover, new refrigerant mixtures are searched from the binary and ternary combination of pure refrigerants using the software REFPROP. The best refrigerant with safety classification A1, A2L, and A2/A3, for both medium temperature (MT) and low temperature (LT) systems is obtained from this search. After their determination, the supermarket’s operation is simulated with these refrigerants. Finally, an environmental assessment is performed. The highest energy efficiency is obtained with R-152a for the MT system and the R-290/R-1270 mixture for the LT system. However, the highest reduction of GHG emissions is achieved by R-290, with a reduction of 73.78 % with respect to the baseline system.