Assessment of thermodynamic and environmental performances in subcooling process for different refrigerants

Abstract

Subcooling application in cooling processes leads to increasing of cooling performance and energy efficiency within defined limits. This study examines subcooling effects of refrigerants on the coefficient of performance (COP), exergy efficiency and environmental performances based on total equivalent warming impact (TEWI) and human health damage (HDD), which are considered environmental parameters, by considering different refrigerants. In the analyses, direct expansion (DX) system, which is used commonly in supermarkets, and the evaporator temperatures of the system 238 and 273 K are taken as reference. In addition, current refrigerants R-22, R-404A and R-507 and the alternative refrigerant R-407C are examined separately. The results of analyses show that the subcooling of 5 K in condenser causes energy saving between 4% and 8% as depending on the refrigerants and provides an increase as the exergy efficiency between 3% and 25%. Besides, HDD and TEWI values also decrease with increasing of subcooling temperature. At the end of the study, effect on system performance of subcooling processes was emphasised as related to exergy and TEWI analyses.