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Cascade CO2 Low Temperature Retrofit

Project Goals

SEER2 was hired to oversee the retrofit of an existing 40,000 sq. ft store in Northern California with a primary focus on 2 existing R507 Medium Temp Racks and an existing R507 Low Temp Rack.

  • Existing medium and low temp racks have loop piping and air-cooled condensers that were installed in 2004.

  • Both Medium Temp Racks were running without issue and their cases were updated during a remodel with most open cases having doors added.

Low Temp Rack required higher than normal maintenance and its cases were original from 2004 with ongoing maintenance issues.

Existing 2004 RTU’s were running on R-22 and past their useful life.

Existing 2004 exhaust fans and makeup air units were experiencing maintenance issues.

Existing 1992 main air handler 5H Direct Drive R407c compressor had failed.


We converted the existing Medium Temp mechanical to R-448A and replaced their air-cooled condensers with Adiabatic condensers.

We replaced the rear load dairy cases with walk-in doors and closed an additional 46’ of open cases with doors.

We replaced the existing Low Temp Rack with Cascade CO2 system and replaced the existing Low Temp glass doors, ice machine, blast chiller, and walk-in coils.

We replaced the Main Air Handler with a Roof-Mounted Desiccant System that will handle 100% of the makeup air and has heat reclaim coils.

We replaced existing RTUs with new reheat units.

We replaced the existing exhaust fans and makeup air units with new ECM and VFD units.

We replaced existing Einstein Medium Temp Rack Controls with new E2 controllers.

We replaced the existing HVAC Metasys controls with E2 controllers. Control/monitor all HVAC equipment and implementing demand ventilation controls that reduce exhaust and outside air requirements.

We replaced the exterior lighting with new LED package.

We implemented and oversaw commissioning and lockdown for the entire store.


The new Low Temp Cascade CO2 system total rack capacity required was reduced by 10% due to the newer, more efficient cases.

Design simplicity of the DX CO2 System keeps the operating pressures consistently lower.

The rear-load dairy case replacement, dairy walk-in extension and installation of new doors collectively reduced the Medium Temp Rack’s load by 21%.

We achieved considerable reduction of the Weighted GWP of the building’s refrigeration and HVAC System.

Rack A Power Calculation was reduced by 93.7%.

Rack B Power Calculation was reduced by 15.5%.

Rack C Power Calculation was reduced by 49.1%.


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