Grocers Can Slash Carbon Emissions with Natural Refrigerants

–With the right planning and implementation, ‘transcritical’ CO2 systems could be a game-changer for cold-storage in grocery and food retailing, advises veteran HFA engineer

BENTONVILLE, Ark., Nov. 15, 2023 /PRNewswire/ — Grocers can advance their sustainability goals by rolling out CO2-based cold-storage systems, but the shift to natural refrigerants requires careful planning and coordination, advises a veteran engineer from HFA Architecture + Engineering.

In a column for Progressive Grocer, HFA Senior Vice President of Engineering Greg Schluterman (P.E., LEED AP BD+C, CXA, ASHRAE BEAP + BEMP) highlights the specific advantages of high-pressure, high-temperature “transcritical” systems based on carbon dioxide, a natural refrigerant otherwise known as R-744.

“What makes carbon dioxide a better choice for fighting climate change?” the executive asks. “While it is, of course, a greenhouse gas, it is far less heat-trapping than the refrigerants traditionally used in conventional, direct-expansion refrigeration and HVAC systems.”

But grocers should be aware of the engineering challenges and upfront costs associated with these systems, Schluterman advises. Shifting to transcritical CO2 requires:

  • A complete change of refrigeration equipment throughout the building, including existing cases. (The evaporator and piping used in traditional, direct-expansion systems, Schluterman explains, are far too large for transcritical CO2 equipment, which is highly compact).
  • Extensive planning, with designs and block-flow diagrams that take into account the space, utility and engineering requirements of the new systems.
  • A potentially longer permitting process, due to the specialized nature of this equipment, which requires careful attention to safety due to the extremes of both temperature and pressure required for using carbon dioxide as a refrigerant.

Based on factors such as their budgets, store lease terms and specific decarbonization targets, grocers and other food retailers can work with engineering firms and energy consultants to determine whether these upfront costs are worth it, Schluterman advises. The HFA executive routinely partners with clients to solve problems and pursue opportunities in growth areas such as EV charging and next-gen refrigeration, as well as using fast-evolving AEC technologies to deliver greater project safety and efficiency.

The advantages of transcritical CO2 can make it well worth some extra efforts, he writes. Operators such as Walmart, Kwik Trip and supermarket conglomerate Ahold Delhaize USA reportedly are among those actively exploring CO2’s potential.

By some calculations, just a pound of the most commonly used hydrofluorocarbon refrigerant—R-22—is nearly as potent in global warming potential as a ton of carbon dioxide, Schluterman observes. Transcritical CO2 systems also “maintain efficiency in hot weather and are extremely effective at capturing heat, which then can be reused for hot water or other needs.”

The engineer notes that one Norwegian SPAR supermarket reportedly slashed its energy consumption by 58% after installing a transcritical CO2 cold-storage system. In Belgium, meanwhile, Ahold Delhaize is routing captured heat to an urban farm as part of its efforts to achieve a 70% cut in emissions by 2050.

Meanwhile, the U.S. government continues to slowly phase out hydrofluorocarbons, and so older refrigerants will be getting more expensive and harder to acquire over time. “Combined with their internal decarbonization targets,” he concludes, “this external pressure is just one more reason for grocers to explore climate-friendly approaches to keeping things cool.”

The full column is available at:

Media Contacts: Jaffe Communications, Elisa Krantz, (908) 789-0700,

SOURCE HFA Architecture + Engineering