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

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 (GPW100=146), R455A (GPW100=146), R468A (GPW100=146), R290 (GPW100=5) and R1270 (GPW100=1.8) have been tested in a horizontal freezing cabinet maintaining a product target temperature of -20 degrees C at the heat rejection temperatures of 20, 30 and 40 degrees 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 degrees C, demonstrating that the enhancement of the IHX is better as higher the heat rejection conditions are.