Performance evaluation of a heat pump system using an HFC32/HFO1234yf blend with GWP below 150 for heating applications

Abstract

Refrigeration and air-conditioning systems become an integral part of modern society. Electricity-driven vapour compression systems have been dominating the heating, ventilation, air conditioning and refrigeration (HVAC&R) industry. The working fluids of these systems often contribute to the environmental issues in the forms of direct and indirection emissions. Pure refrigerants are often limited in meeting criteria such as efficiency, flammability, toxicity, and compatibility. Meanwhile, refrigerant mixtures offer flexibilities to tune these criteria, and the reusability of the existing hardware is often a priority in practice. We evaluated a binary mixture of HFC32 and HFO1234yf with a target global warming potential (GWP) under 150 for domestic heat pumps. Drop-in tests were conducted for two modes; Heating#1 and Heating#2 at different condensing temperatures. The performance of the current binary refrigerant was compared with those of target refrigerants, i.e., R410A, HFC32 and the binary mixture of HFC32/HFO1234yf (22/78 mass%, GWP = ~300) for part- and full-load operations. Experimental results showed that the performance of the present refrigerant is comparable with R410A and HFC32 for high condensing temperatures, especially at part-load operations. The system COP of the current binary blend exhibits from 6 to 14% drop as compared to that of R410A. A significant increase in the system irreversibility losses was observed with the increasing percentage of HFO1234yf. Despite the relatively low performance, the GWP of the present refrigerant is below 150, and it can be used in the existing systems without significant hardware changes while meeting tighter environmental regulations.