リスクトレードオフを考慮した次世代低GWP 冷媒の選定

Abstract

Because the refrigerants currently used in air-conditioners have high global-warming-potentials (GWP), substances with lower GWPs, such as R-1234yf, are considered to be candidates for next-generation refrigerants. However, low-GWP substances often have comparatively high chemical reactivity and may carry increased risks of combustibility, toxicity, generation of degraded products, and increased CO2 emission caused by poor energy-saving performance. Therefore, a possible risk trade-off exists between currently used refrigerants and those with low-GWPs. In this research, I proposed a framework for evaluating this trade-off in the following five categories: (1) environmental characteristics; (2) combustion characteristics; (3) toxicity; (4) volume of greenhouse gas emissions; and (5) applicability to air-conditioning equipment. I then selected substances well suited as next-generation refrigerants in accordance with a specific screening process. I showed the importance of clearly specifying the combination of a number of end points and assessment criteria in the process of decision-making based on risk trade-off. This method yielded a rapid understanding of the necessary data, as well as flexible decision-making that is relevant to social conditions.