FIELD MEASUREMENTS OF A R404A LOW-TEMPERATURE SUPERMARKET REFRIGERATION SYSTEM RETROFITTED WITH R449A

摘要

Current international regulations set incentives to replace refrigerants with high global warming potential (GWP) values using environmentally friendly alternatives. This study presents the field measurements of an indirect commercial refrigeration system retrofitted with R449A, an alternative to R404A with a GWP value of 1282 (67% lower than that of R404A). The system has been operated at low evaporation temperature conditions(secondary refrigerant temperatures from -34 to -25°C). The results indicate that the cooling capacity of the retrofitted system was 1.3% lower than that of the reference R404A system on average, while the COP values are higher when using R449A (8.1% increase on average). The compressor discharge temperature increase is approximately 18.5 K. As a conclusion, R449A can be used as a replacement to R404A in indirect low-temperature supermarket refrigeration systems given that implications of its higher compressor discharge temperature, lower mass flow and difference in transport properties are taken into consideration.