Experimental evaluation for potential drop in refrigerants under high-ambient conditions

Abstract

Compliance with the Kyoto Protocol and United Nations Sustainable Development Goals requires nations to lower greenhouse gas emissions. Air conditioners, as contributors to direct and indirect emissions of greenhouse gases, can play a major role in limiting global warming to 1.5 °C above pre-industrial levels. Nations classified as Article Five parties, including 147 nations, are required to completely phase out Hydrochlorofluorocarbons including R-22 in 2040. Some of these nations reside in extremely hot climates, and new refrigerants perform poorly under hot weather conditions. While the time is ticking to the phaseout, transitional solutions can be used to move away from R-22 to facilitate the phase-down, especially for units that are still in service.In this paper, a comparative experimental assessment of R453A and R458A as drop-in replacements for R22 is presented. This study aims to evaluate the performance of the two refrigerants to assess their suitability for countries residing in hot climates during the transitional phase-out and phase-down of refrigerants. R22 is used as the baseline refrigerant because it is widely used in developing nations and performs well under high ambient temperatures, reaching as high as 50 °C. Six ambient temperatures (35 °C, 40 °C, 46 °C, 48 °C, 50 °C, and 52 °C) were tested to evaluate the performance of a concealed ducted split air-conditioning unit. The unit rated cooling capacity is 10.39 kW at 48 °C. The measured cooling capacity in comparison to that of R22 was between 87 % and 96 % and 88 % to 96 % for R453A and R458A, respectively, over the tested range of temperatures. The coefficient of performance compared to the baseline showed degradation of 6 %–17 % and 3–10 % for R435A and R458A, respectively. The compression ratio increased by 9 % to 15 % on average for both tested alternative refrigerants over the tested temperature range. It is concluded that R458A performs well as a drop-in alternative refrigerant to R22 and surpasses that of R453A, as it showed slightly less deviation in coefficient of performance.