Distributed CO2 (R744) refrigeration systems such as small racks and condensing units could play a growing role in North America. 

That was the message from Andre Patenaude, Director for Solutions and Strategy at U.S. manufacturer Emerson, during a webinar at the ATMO World Summit on March 30. The World Summit was organized by ATMOsphere (formerly shecco).

“There really is a place for distributed CO2 systems,” Patenaude said. “What we’ve seen, for the most part, in North America to date are large centralized [CO2 ] systems, but with the advent of smaller CO2 compressors, there’s a lot more activity developing systems that are smaller.” 

This is a trend Emerson is seeing around the world, and these systems are also starting to be introduced in North America, Patenaude added. “This is important to retailers, for example if someone is looking at a remodeling strategy,” he stressed. 

For example, if a retailer has a lineup of display cases that have reached the end of their life, they can change these lineups, and replace them with a small distributed CO2 refrigeration system. They can then later start transitioning more assets in the store to CO2, Patenaude explained. 

Another benefit to having a distributed CO2 refrigeration system architecture, with for example three or four units around the store, is that it can save energy. With this layout “you can start optimizing medium-temperature suctions to improve energy further,” Patenaude noted, pointing out that the distributed medium-temperature suction pressures can be higher than they would be in a common circuit with a low-temperature load. “I think there’s definitely a need and a want for these types of systems.”

In the adoption of  CO2 condensing units, the North American market is still lagging behind Europe, but “we do have end users starting to request these types of units,” Patenaude said. He noted that while Emerson does not plan to manufacture CO2 condensing units, it does intend to mobilize its OEM customers to manufacture them.

Referencing a 2021 survey by the North American Sustainable Refrigeration Council (NASRC) Patenaude noted that 39% of the end users said that CO2 condensing units would be a good choice when they add additional load to a system. Another 39% said that when they are planning new remodeling strategies, CO2 condensing units would work well.  

Condensing units are also useful as the refrigeration system for smaller grocery stores and convenience stores. Moreover, if they have an attached car wash, they can get some good heat reclaim from the CO2 condensing unit that can be used to heat the water, Patenaude pointed out. 

“So, the need is there, but it takes a bit longer as you need to ‘Americanize’ the units and get approval of initial European designs, and that takes a bit longer, but the need is there, and the requests are starting to mount,” he said.

At the same time, Patenaude believes that distributed CO2 racks will be more popular than CO2 condensing units due to overall lower costs. “One CO2 pack will be able to handle significantly more loads than an individual condensing unit; therefore the lower Capex,” he said.

Emerson has been increasing its global R&D efforts, focusing on simplifying the application of CO2 refrigeration systems. The company has recently launched two new controllers that require less programming than previously, expanded its CO2 compressor portfolio and adopted a new communication and education strategy.

Along with the new products, Emerson is engaged in building four new labs for CO2 technology development that will open in July at its Sidney, Ohio, campus.

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