Comprehensive analysis of R600a/R1150/R50 on performance, economy, and environmental impact of auto-cascade refrigeration system: Experimental study.

Deep cryogenic temperatures were widely applied in various fields such as biomedicine, aerospace, and fundamental physics research. The Auto-cascade Refrigeration Cycle was one of the primary methods for achieving temperature requirements ranging from -40 ◦C to -180 ◦C. However, with the implementation of environmental agreements, the use of refrigerants with lower Global Warming Potential had become a trend in refrigeration system development. To investigate the impact of low-GWP mixed refrigerants on ARC system performance, this paper focused on a typical three-stage self-refrigerating cascade system, selected R600a, R1150, and R50 as refrigerants, analyzed the impact of Hydrocarbons(HCs) mixed refrigerant ratios on evaporation temperature, system refrigeration capacity, COP, and other ARC performance, and compared the characteristics with the ARC system using R600a/R23/R14 mixed refrigerants. The results showed that the mixed refrigerants R600a/R1150/R50 had an optimal mass fraction in the ARC; that is, when the ratio of R600a, R1150, and R50 was 73/15/12, the evaporation temperature was lowest at -125.3 ◦C, and the COP was relatively high at 0.15. The change in the mass fraction of R50 has a greater impact on ARC. A 9 % increase in mass fraction results in a 17 % increase in ARC cooling capacity, but only an 9 % decrease in COP to 2.5 %. The discharge temperature of HCS systems is 15 % higher than that of R600a/R23/R14 systems, but the GWP of HCs is 99.6 % lower than that of the latter. The use of HCs reduces set-up costs(SET) by more than 90 % and reduces carbon emissions by more than 47 %.