Designing CO₂ Systems for Warmer Climates

This news is about commercial refrigeration, not home heating or cooling, but it's worth understanding if you're curious about where cooling technology is headed. Supermarkets and other large facilities increasingly use CO₂-based refrigeration instead of traditional synthetic refrigerants, and engineers used to assume CO₂ systems lost too much efficiency in hot climates to be worth using. That assumption is changing.

The shift comes down to design rather than the refrigerant itself. CO₂ systems in hot regions, including the U.S. Sun Belt and Mexico, are now built around a "gas cooler" (the hot-climate equivalent of a condenser) sized for the hottest days a site will see, along with variable-speed fans, extra compressors to handle pressure changes, and sometimes heat recovery that reuses waste heat for things like hot water. A supermarket project in South Korea, engineered for 100°F peak heat, ended up running about 34% more efficiently than a comparable system using the older refrigerant R-404A. Some very hot, dry sites also use a water-based pre-cooling step to help the system work less hard, though that trades off against water use.

None of this changes what's available for home heat pumps or air conditioners today, but it signals that CO₂, a natural refrigerant with a much lower climate impact than many synthetic ones, is becoming more viable even in extreme heat. That matters because refrigerant choices made in commercial systems now often trickle down to residential equipment over time.