Assessment of total equivalent warming impact (TEWI) of supermarket refrigeration systems

Refrigeration system of supermarket applications significantly contributes to direct and indirect global warming. The aim of this paper is to present a methodology of assessing such systems in terms of refrigerants, machinery and operational protocol to minimize the total equivalent warming impact (TEWI). Another perspective is painted for the refrigeration industry to ameliorate environmental impact. Air-cooled refrigeration system is analyzed for low temperature (LT) evaporation at −20 °C and medium temperature one (MT) at 0 °C with condensation at 40 °C. The effects of suction superheat and subcooling have also been accounted for. Various refrigerants such as HFC 134a, HFC blend 507A and their combinations are considered as working fluids for catering to a LT load of 50 kW and MT load of 250 kW. It is observed that HFC 134a for LT and MT gives the best combination. In addition, the impacts of COP on the TEWI for transcritical CO2 systems were also estimated. Based on our results, HFC blend 507A refrigerants have the highest TEWI along with the maximum economic loss. Transcritical CO2 refrigeration system with conceivably higher COP in the operating conditions are found to be the best from the TEWI perspectives with minimum economic loss due to refrigerant leakage because of its abundance availability.