A3 and A2 refrigerants: Border determination and hunt for A2 low-GWP blends

Abstract

The hunt for new refrigerant blends has been concentrated to locate A1 refrigerants. However, the investigation for A2 or A2L blends to replace hydrocarbons (A3) has not attracted attention yet, although these mixtures will allow to increase the maximum charge of refrigeration systems from 500 g to 1200 g. This paper extends Linteris’ et al. work to define, for first time, the frontier between A3 and A2 ASHRAE safety classifications with an approach that can avoid large experimental campaigns. Then, using the methodology, it determines the composition limits of possible A2 binary blends with hydrocarbons that have a GWP below 150. Only mixtures of hydrocarbons with A2 or A2L components meet the criteria, and the composition of the least flammable fluid is predominant. Proposed hypothesis, developed theoretically, should be completed in the future with experimentation, to quantify the energy performance of found blends.