Case Studies

Whole Foods Market

Whole Foods Market, Santa Clara partnered with M&M Carnot to develop a propane/CO2 cascade refrigeration system that would reduce operational costs while lowering Global Warming Potential.

Market Customer


To comply with corporate sustainability initiatives, Whole Foods Market was searching for a natural refrigeration solution that would use propane as a viable primary refrigerant in their centralized supermarket rack system.

grocery store cooler aisle


To meet the challenge, M&M Carnot designed and installed a propane/CO2 cascade refrigeration system containing 265 lbs. of propane spread across seven rooftop chiller units, including three for low-temperature and four for medium-temperature applications. The system’s propane never leaves the roof and is used to condense its refrigeration partner, CO2. The CO2 is piped up from a rack inside the building, directly below. Liquid CO2 is then piped down to DX evaporators in low-temperature cases and pumped to liquid-overfeed coils in medium-temperature cases.


Whole Foods is experiencing impressive results with their new propane/CO2 cascade refrigeration system. Propane’s miniscule global warming potential (three), effectiveness as a working fluid, efficiency, affordability, and safe operation were all attractive customer benefits. M&M Carnot’s user-friendly propane solution also provided a low compression ratio, high COP, very good heat transfer, and easy oil separation.

Global Warming Icon

System delivered a Global Warming Potential of 3.

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