Techno-economic and environmental analysis of low-GWP alternative refrigerants in cold storage unit under year-round working conditions

The impact of refrigerants with high global warming potential (GWP) on climate change necessitates the use of alternative refrigerants in cold storage systems. Designed cold storage units using low-GWP alternative refrigerants to R404A, i.e., R407A and R407F, are experimentally studied respectively in this study under year-round working conditions (ambient temperature of 32, 25, 15 and 5 °C). The year-round performance of the units in terms of energy saving and safety under three super-heating degrees (SHs) are also investigated. In each working condition, the performance of cold storage unit using R404A, R407A and R407F is compared in terms of the cooling capacity, energy efficiency ratio, sub-cooling degree, condensing temperature, evaporating temperature and discharge temperature (T_d). The results show that the annual energy effect ratio of the unit with R407A and R407F is higher than that of R404A, however the T_d of R407F is at an unfavorable level for safety at high ambient temperatures. The annual power consumption, life-cycle cost, total equivalent warming impact and life cycle climate performance of R407A are lower than those of R404A by 2.5%, 2.2%, 7.9% and 7.9%, respectively, and those of R407F are lower than those of R404A by 4.6%, 4.2%, 11% and 14.5%, respectively, indicating R407F is a better low-GWP alternative refrigerant for cold storage systems.