Replacement of R404A at high condensation temperature using R454C and R455A.

R404A must be replaced for all commercial refrigeration applications following the instructions of the European F-gas Regulation. The recently developed mixtures R454C and R455A offer Global Warming Potential below 150, solutions with an ASHRAE 34 flammability classification of A2L. This paper presents and compares the experimental results of a refrigeration system using R404A, R454C and R455A, at a condensation temperature of 47 °C and evaporation temperatures of -13 and -30 °C. The experimental results show that, when using the alternative refrigerants instead of R404A, the refrigerating effect is increased, but the compressor suction density is lower. While the volumetric cooling capacity of R455A is comparable, that of R454C is lower than R404A. The coefficient of performance with both alternatives is significantly higher, so there is an energetic and hence environmental benefit from their utilization. The discharge temperature is within the limits, but it can be a limitation in higher compression ratios. The drop-in replacement only required adjustments in the TXV screw and in the refrigerant charge.