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Nonresidential Refrigeration System Opportunities

Measure Description

The California Energy Code (Title 24, Part 6) currently includes mandatory efficiency requirements for refrigeration systems serving refrigerated warehouses and retail spaces with walk-in coolers or freezers or refrigerated display cases. This measure proposes code change proposals that will improve energy performance end reduce greenhouse gas (GHG) emissions from refrigeration systems in refrigerated warehouse, retail stores, and commercial kitchens. Requirements for commercial kitchens would apply to a variety of building types including restaurants, schools, and hospitals. 

Establish Design and Control Requirements for Transcritical CO2 Systems 

Historically, refrigeration systems have used halocarbon refrigerants that have high global warming potential (GWP), but use of these high GWP refrigerants is being phased out in California (Health and Safety Code Section 39730.5). Many types of refrigerants will no longer be allowed for us in supermarket refrigeration or refrigerated cold storage by the time the 2022 Title 24, Part 6 standards take effect in January 2023.  As high GWP refrigerants are being phased out, transcritical CO2 systems are becoming more prominent. Specific code requirements will be determined as part of the advocacy effort but may include requirements for sizing and efficiency of gas coolers for heat rejection, implementing parallel compression system configuration, and heat pressure control strategies. The requirements would apply to refrigeration systems in refrigerated warehouses, retail spaces (e.g., supermarkets), and commercial kitchens.  

This measure will establish design and control requirements for transcritical CO2 systems utilized in both commercial refrigeration and refrigerated warehouses. Proposed measures include minimum sizing for gas coolers, minimum gas cooler specific efficiency, floating head pressure control, parallel compression, and gas ejectors. These measures would not mandate that CO2 systems be required, but it would establish mandatory design and control requirements that will optimize energy performance should a designer elect to use these systems. 

Establish Design and Control Requirements for Large Packaged Systems 

As part of an effort to reduce the ammonia charge as compared to what is required for typical built up central ammonia systems, multiple manufacturers have developed large packaged systems for use in refrigerated warehouses. This measure will establish design and control requirements for these large packaged systems. Proposed measures primarily will address condenser sizing and condenser specific efficiency, as the current code requirements for traditional central systems may not be economical/applicable to packaged systems. 

Evaporator Minimum Specific Efficiency for Refrigerated Warehouses 

This measure will define mandatory minimum specific efficiency requirements for evaporators in refrigerated warehouses. Specific efficiency is a metric that determines the amount of cooling an evaporator can provide per unit of input power required.  This is similar to the metric of specific efficiency currently defined in Title 24 for evaporative, air cooled, and adiabatic condensers.  Specific efficiency requirements are expected to be defined for different refrigerants and evaporator types. 

Require Automatic Door Closers 

This measure would require walk-in coolers to have automatic door closures. There are two types of closures. One is the spring or gravity/cam hinge that closes the door from a standing-open position to a closed position. The second is the closure devices that snaps the door tightly closed (when magnetic gaskets are not applicable). This code change proposal would define both types of closures and require them both for walk-ins.  

Acceptance Testing for Commercial Refrigeration 

This proposed measure would add acceptance testing to verify compliance with existing code requirements for commercial refrigeration systems.  

Relevant Documents

Measure proposals, supporting documents, and other outside references will be made public as they become available.

Round Two Utility-Sponsored Stakeholder Meeting Materials

Round One Utility-Sponsored Stakeholder Meeting Materials

Provide Feedback

This measure description will be updated as research is developed to support the 2022 code cycle. For questions or suggestions, email Include the measure name in the subject line.

Give Us Your Feedback

The Statewide CASE Team values input from all stakeholders engaged in the Title 24, Part 6 code change process. We encourage the open exchange of code change comments and concerns.

  • Use the form above to provide feedback on this measure.