Optimizing R152a/R600 and R290/R600 mixtures for superior energy performance in vapor compression systems: Promising alternatives to Isobutane (R600a)

Abstract

This study presents an experimental investigation into the optimal composition of R152a/R600 and R290/R600 mixtures as potential alternatives to isobutane (R600a) in a single-stage vapor compression cycle. The research involved testing eight different mass compositions for R152a/R600 and ten mass compositions for R290/R600, comparing their performance with that of R600a. After careful analysis, the “optimum” mass compositions were identified as (10/90)% for both R152a/R600 and R290/R600, achieving a balanced trade-off among coefficient of performance (COP), volumetric cooling capacity (VCC), and cooling output (Q̇o). Further tests were conducted on the “optimum” compositions at nine different secondary fluid temperature inlets. The results indicated an average COP increase of + 7.3 % for the R152a/R600 mixture, with decreases of −11.4 % in VCC and −9.7 % in Q̇o. Similarly, the R290/R600 (10/90)% mixture showed a COP increase of + 10.3 %, accompanied by VCC and Q̇o decreases of −8.8 % and −6.6 %, respectively. Notably, both mixtures exhibited superior energy performance compared to isobutane while maintaining similar thermodynamic properties, particularly the R290/R600 (10/90)% mixture. These findings suggest that the R152a/R600 and R290/R600 mixtures could serve as long-term, high-efficiency alternatives to R600a in vapor compression cycles.