Heat Pump Systems with Low GWP Refrigerants [5]

Throughout the last few decades, there has been a significant effort to improve the environmental impact of refrigerants used in residential air conditioning systems. Since the current refrigerant, R410A, has a high GWP value of 2,088 when it leaks out of its air conditioning system, it has a tremendous effect on the buildup of greenhouse gasses. Fortunately, researchers and engineers across the world are actively working to search for low-GWP solutions to R410A such as natural refrigerants and newly-identified synthetic refrigerants. Since these refrigerants have quite different thermodynamic and heat transfer characteristics from currently used R410A and encountered new design challenges such as a charge limit associated with safety, transitioning to lower-GWP refrigerants requires a whole-system approach. To accelerate the promotion of low-GWP refrigerant applications the Internal Energy Agency’s Heat Pumping Technology (IEA-HPT) started Annex 54: Heat Pump Systems with Low GWP Refrigerants” in 2019. This annex aims at developing design guidelines for optimized heat pump components and systems for low-GWP refrigerants. Annex 54 participants are Austria, France, Germany, Italy, Japan, South Korea, Sweden, and the U.S. This presentation provides an update of Annex 54 activities in 2020. A comprehensive review was conducted for the R&D progress on components using low-GWP refrigerants for residential applications. The review particularly focused on heat exchangers and compressors. Furthermore, it presents a study on circuitry optimization of tube-fin heat exchangers. It also presents highlights of several projects on heat pumps using low-GWP refrigerants by Germany, Italy, Italy, and Sweden.