Refrigeration Systems Chillin’ With Carbon Dioxide

Growing U.S. Interest

Though it’s the first North American retailer with transcritical systems, Sobeys has been joined by other Canadian retailers, such as Overwaitea and Metro, according to Luc Simard, senior engineer, CSC, which supplies transcritical refrigeration equipment (pictured) to those retailers as well as Sobeys. Another Sobeys supplier, Carnot Refrigeration, has two other transcritical installations under way in Canada, and one in the U.S., said Marc-André Lesmerises, vice president of engineering for Carnot.

One of the key stumbling blocks to U.S. implementation has been the absence of UL (Underwriters Laboratories) approval for transcritical compressors due to the high-pressure issue. However, UL approval is expected to come this year for compressors made by at least two U.S. manufacturers, said Simard, who now orders his transcritical compressors from Europe. “This will change the availability of transcritical systems for the U.S. market,” he said.

With the UL issue almost resolved, there is an increasing focus on transcritical systems by U.S. retailers. For example, Fresh & Easy Neighborhood Market, El Segundo, Calif., is “evaluating the opportunity” to test a transcritical system, and could do so early next year, said Steve Hagen, procurement and engineering director for the chain, a division of U.K.-based Tesco, which uses transcritical systems in the U.K. “I think in mild climates, transcritical is the future of the industry,” he said.  “CO₂ is a natural refrigerant, so you won’t have to worry about it being phased out.”

Fresh & Easy is one of the food retailers in the Environmental Protection Agency’s GreenChill Advanced Refrigeration Partnership that have expressed “a lot of interest in CO₂ transcritical systems,” according to a statement supplied by the EPA.  “Some GreenChill partners are working on CO₂ transcritical pilot projects,” the agency said. “Many are thinking about transcritical systems, but they may be holding back and waiting to see what others do.”

Executives from Hill Phoenix, Conyers, Ga., which also supplies refrigeration technology to Sobeys (though not yet transcritical equipment) and many U.S. retailers, also see interest in transcritical expanding in the U.S. “There are a bunch of retailers that want to be first,”  said Scott Martin, director of advanced engineering, Hill Phoenix. Queries are coming from both warmer and cooler climates. “There’s a retailer that wants to put one in Southern California,” he said.  Rusty Walker, senior trainer with the Hill Phoenix Learning Center, said in a recent GreenChill-sponsored webinar that a transcritical system is being installed in the New York area this summer.

Part of the interest in CO₂ refrigeration derives from a desire by a many retailers to move away from using HFC and other fluorinated refrigerants for environmental reasons, since they are from 1,500 to 4,000 times more potent that carbon dioxide as a greenhouse gas contributing to global warming. For example, while CO₂ has a global warming potential of 1, R-404A’s GWP is 3,922. So-called F-gases, which include HFCs and HCFCs, are projected to be responsible for 9% to 19% of annual greenhouse gas emissions by 2050, according to the U.K.-based Environmental Investigation Agency.

In November 2010, at the Cancun Climate Summit, the Consumer Goods Forum, Paris, a group of about 400 global retailers and CPG manufacturers, pledged to begin phasing out HFC refrigerants by 2015 and replace them with non-HFC refrigerants, such as CO₂, other natural refrigerants and other low-GWP synthetics. “This is the first time that the entire sector has aligned around the importance of taking action to accelerate the move to climate-friendly refrigeration,” said Lars Olofsson, chief executive officer of French food retailer Carrefour, and Muhtar Kent, CEO of Coca-Cola, in a statement at the time. Other Forum member companies associated with the pledge include Ahold, Delhaize, Wal-Mart Stores, Sobeys, Tesco and Metro.

And at the 23rd Meeting of the Montreal Protocol Parties last November, EPA and the U.S. Department of State announced that 108 countries signed a declaration to address HFCs.

The adoption of non-fluorinated refrigerant is still in its infancy in the U.S., though interest is growing fast, said the EPA. “Some GreenChill partners are considering non-fluorinated refrigerants with low GWPs as a long-term solution,” the agency said. Carbon dioxide is the most prevalent of the non-fluorinated refrigerants in U.S. supermarkets, mainly due to its use in cascade and secondary systems as a low-temperature secondary fluid, rather than as a primary refrigerant.