Energy impact of the Internal Heat Exchanger in a horizontal freezing cabinet. Experimental evaluation with the R404A low-GWP alternatives R454C, R455A, R468A, R290 and R1270

Abstract

• It has been tested the IHX effect in the energy performance of a freezing cabinet. • Test has been carried out with R404A and its current low and ultra‐low GWP alternatives: R468A, R454C, R455A, R290 and R1270. • It has been measured Energy saving with all refrigerants and operating conditions tested. • Greater energy saving as greater the heat sink temperature is. • No significant increment in compressor discharge temperature. This work analyses the influence of the Internal Heat Exchan ger (IHX) on the energy performance of a vapor compression cycle associated with a freezing cabinet using different R404A low-GWP alternatives. Among them, the refrigerants R454C (GPW 100 =146), R455A (GPW 100 =146), R468A (GPW 100 =146), R290 (GPW 100 =5) and R1270 (GPW 100 =1.8) have been tested in a horizontal freezing cabinet maintaining a product target temperature of -20°C at the heat rejection temperatures of 20, 30 and 40°C. The results from tests show that the use of the IHX reduces energy consumption in all scenarios without significantly increasing the compressor's discharge temperature. For a test period of 16 h, the refrigerants that offer better reductions are R404A and R1270, followed by R455A, R290, R454C and R468A. The maximum energy saving is rated to 9.2% at the heat rejection temperature of 40°C, demonstrating that the enhancement of the IHX is better as higher the heat rejection conditions are.