R-454C, R-459B, R-457A and R-455A as low-GWP replacements of R-404A: Experimental evaluation and optimization

This work evaluates R-454C, R-459B, R-457A and R-455A as R-404A low-GWP substitutes in a stand-alone commercial refrigeration system for fresh product under ISO 23953-2. System is tested with and without receiver. Charge was optimized based on energy consumption tests in climatic chamber. A significant increment of the evaporating temperature of the new mixtures has been observed, which mitigate the negative effects associated to the large glide. Operation is compatible with R-404A for this system, offering energy consumption reductions for optimized charges without receiver of: 2.07% with R-454C, 10.76% with R-459B, 10.48% with R-457A and 2.95% R-455A. Energy consumption reductions with receiver are of 2.45% with R-454C, 11.55% with R-459B, 10.69% with R-457A and 2.9% with R-455A. In most of the cases the optimum refrigerant charge was below R-404A one. It is concluded that R-404A low-GWP substitutes can reduce refrigerant charge and improve energy performance in relation to R-404A. (C) 2019 Elsevier Ltd and IIR. All rights reserved.