Mandatory Requirement Updated Guidance
The 2025 Energy Code sections 120.6(a)8A and 120.6(b)5A prohibit air-cooled gas coolers in new transcritical CO2 refrigeration systems in refrigerated warehouses in climate zones 9 – 15, and in commercial refrigeration in climate zones 10 – 15, respectively.
Several interested members of the public have submitted comments to the California Energy Commission (CEC) expressing concerns that prohibiting air-cooled gas coolers could discourage installation of lower-capacity transcritical CO2 refrigeration systems typically used in smaller grocery stores or convenience stores. The alternative to an air-cooled gas cooler is an adiabatic, or similar, water-cooled gas cooler. For these lower-capacity refrigeration systems, the increased water use, maintenance needs, and initial costs of the alternative gas coolers can exceed the costs assumed in the technical analysis used to develop the adopted Energy Code requirements.
Investigation by CEC staff determined that the analysis supporting the mandatory requirements for refrigeration systems focused on large, refrigerated warehouses and large supermarket buildings with capacities of more than 80 tons. Staff also note that as part of a 2028 Energy Code measure proposal, a market review of available air-cooled gas coolers used in small commercial refrigeration and small refrigerated warehouse applications was performed. This review proposes a minimum size threshold of 20 tons for freezers and 40 tons for coolers, where the availability of smaller systems with air-cooled gas coolers were readily available. The CEC received positive feedback from the public on this measure proposal. The 2028 Energy Code Covered Process Refrigeration Final CASE Team Comment Letter, which evaluates these systems, is available on the CEC website.
Based on the original analysis, CEC staff recommend that enforcement agencies apply the mandatory requirements in sections 120.6(a)8A and 120.6(b)5A only to air-cooled gas cooler systems with capacity greater than 80 tons. CEC staff note that docketed comments and additional public feedback support applying the mandatory requirements to freezer systems with capacity greater than 20 tons, and cooler systems with capacity greater than 40 tons.
Further Information
Questions about this guidance or the Building Energy Efficiency Standards in general may be directed to the Energy Code Hotline Submission Form.