CO2 as a refrigerant has been a part of the refrigeration landscape for close to a decade — from early efforts combining it with ammonia in cascade systems for industrial plants, to cascade and other approaches with HFC refrigerants in supermarkets.
The most anticipated next step was running CO2 as a standalone refrigerant in a system, which is being done in Europe in more and larger applications. Finally, the approach crossed the Atlantic and made a high profile debut less than a year ago in Brooklyn, New York.