In the food cold chain, R-404A and R-22 are very widely used. But the ban of R-22 is now completed orongoing according to the regions. Due to its very high GWP, R-404A will also be subject to bans orrestrictions in the future. To replace R-22 and R-404A, over twenty synthetic refrigerants, mostly blends, areproposed by various producers and referenced with ASHRAE classification. This multiplicity of products isconfusing. Some are proposed as alternatives to R-22, or to R-404A, or both. Some are flammable; others arenot. GWP’s can vary in a wide range. This paper provides the basic concepts to understand why and whenblends are needed, and the link between their formulation and their key physical and environmentalproperties: operating pressures, temperature glide, volumetric capacity, GWP, and flammability. The mostcommonly proposed alternatives are analyzed to provide some understanding of the trade-offs between GWP,flammability, and key physical parameters.
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