Energy, exergy, environmental and exergoeconomic (4E) analysis of an ultra-low temperature cascade refrigeration system with environmental-friendly refrigerants

Abstract

To ensure the efficacy of some special vaccines, the ultra-low temperature storage below −80 °C is strictly required and the classical cascade refrigeration system has a good application prospect in the production, storage, transportation and distribution of COVID-19 vaccines. Previous investigations are mainly focused on the thermodynamic performance of cascade refrigeration cycles (CRSs) to generate low temperature, and the impact of cascade refrigeration cycles on environmental and exergoeconomic aspects is few involved. In this paper, an energy-exergy-environmental-exergoeconomic (4E) analysis model was built to investigate the comprehensive performance of an ultra-low temperature cascade refrigeration system. Eight environmental-friendly refrigerant pairs, including R290-R170, R290-R1150, R717-R170, R717-R1150, R1270-R170, R1234yf-R170 and R1234yf-R1150, were chosen and the associated refrigeration performance was compared. The results show that the optimal refrigerant pair is propane-ethane (R290-R170). Compared with HFC refrigerant pair R404A-R508B CRS, R290-R170 CRS could improve the COP by 5.94%, save 5.68% power consumption, reduce 29.67% carbon dioxide emission and decrease 5% exergy economic cost. This work is significant to select environmental-friendly nature refrigerants, enrich understanding of comprehensive performance of cascade refrigeration system and enhance depth research on ultra-low temperature refrigeration.