Drop-in substitutes for R-600a. Experimental evaluation and optimization of a commercial fridge

Abstract

This work aims to validate the hypothesis that refrigerant blends could allow energy savings in real refrigeration systems. For that purpose, five selected blends have been evaluated as drop-in substitutes in a domestic fridge for fresh food designed for R-600a under laboratory conditions. Mixtures, selected from an initial theoretical work, were subjected to a charge optimization process following the standard EN 62552-2:2020. At their optimum refrigerant charge, three offered energy savings: 2.15% is obtained with the mixture R-600a/R-1234yf [92.5/7.5%]; 3.84% with R-1234ze(E)/R-600 [10.5/89.5%] and 1.31% with R-600/R-290 [89.0/11.0%]. This work discusses the experimental procedure and the operating parameters of the selected mixtures in relation to R-600a. Thus, it has been verified that energy savings could be obtained with refrigerant blends. However, understanding the operation of the mixtures requires further investigation not covered in this work.