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North America // End User

Walmart’s overall refrigerant strategy calls for moving away from high-GWP refrigerant gases, including HFCs, to refrigerant gases with low- and ultra-low GWP “for new systems as they come commercially viable by 2025,” said Ragland, adding that Walmart was “the first retailer to set an approved sciencebased emissions reduction plan to 2025.” Walmart is also working to reduce refrigerant use and improve efficiency in current systems and install new systems that are “high-efficiency” and “less susceptible to leaking,” she said. The company reduced its refrigerantrelated direct emissions by 10% between 2016 and 2018, she noted. Last year Walmart reported operating 11,700 stores in 28 countries. Ragland acknowledged that “much of [Walmart’s refrigerants] are HFCs.” Walmart is a member of the Consumer Goods Forum, a global consortium of retailers and packaged goods companies that has pledged since 2015 that its members would take steps to cut their high-GWP emissions (https://bit. ly/31DCQni). Ragland comments came in response a new HFC - reduction campaign launched by GreenAmerica.org, a nonprofit environmental group founded in 1982. The campaign, called “Cool It!” (https://bit.ly/2N4WpRu), initially targets Walmart and urges the retailer to “phase out harmful HFCs, track and repair its refrigerant leaks, and commit to responsible disposal.” “Walmart has known the urgency of this issue for years but has not taken serious steps to put its words into action,” said GreenAmerica.org on its website. “We’re calling on Walmart to finally develop a plan to cut these harmful super pollutants from its stores.” On its website the group has also set up a petition form so that anyone can email this message to Doug McMillan, Walmart’s CEO, and Kathleen McLaughlin, its chief sustainability officer.

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Secondary CO2 systems Walmart has in the past installed refrigeration systems that use HFCs as the primary refrigerant and CO 2 as a secondary fluid. However, it discontinued using those systems in 2014, according to an industry source. The company did not reply to a request for comment on its discontinuation of those systems. In a 2013 report called “The Dirty Dozen: How your local supermarket is killing the climate” (https://bit.ly/33yGKzC), the U.S. branch of the Environmental Investigation Agency (EIA) said that “Walmart is using a secondary loop refrigeration system that combines either carbon dioxide or glycol and HFCs in more than 125 stores and two Sam’s Club stores in the U.S.” One example of a Walmar t store with a secondar y CO 2 system is a M a s s a c h u s e t t s S u p e r c e n te r converted from a traditional Walmart. The system includes a secondary medium-temperature glycol system and a secondary CO 2 low-temperature system, noted Stan Shumbo, VP at Colchester, Conn.- based Eastern Refrigeration, which installed it. (See, “Gaining Natural Experience,” Accelerate America, May 2018.) In its 2018 Global Responsibility Report ( https://bit.ly/2jh9WoV ), Walma r t said that its engineers from multiple markets have been “working on bringing distributed packaged refrigeration systems into our stores and clubs. These ‘plug and play’ units are poised to simplify the business of refrigeration for many of our markets in the coming years. “This approach to refrigeration design will suppor t quicker installations, reducing store interruptions and are packed with the latest thinking in energy efficient technology and on-board system diagnostics. These systems are designed to use less refrigerant gas, less copper pipe and to be simpler to maintain.”

The report did not disclose which refrigerant it would use in these units, though plug-and-play display cabinets using propane (R290) have become more prevalent in Walmart’s home U.S. market. The Global Responsibility Report also noted that Walmart’s grocery distribution centers utilize “large ammonia systems” for cooling. In recent years, it added, the company has “worked with our vendors to design a smaller version that could be used in our regional distribution centers.” These small ammonia plants are designed “to double the life expectancy of the old plants, use less energy through reduced horsepower and eliminate over 200 pounds of freon.” Asda, Walmart’s retail business in the U.K., is testing a system called Mistral, which uses chilled ducted air to cool products held in display cases. According to a 2017 report from the University of Birmingham, U.K. (https:// bit.ly/2Tz7I5w), the system’s cold refrigerant gas is pumped to a large air handling unit on the roof directly above the aisles; then the cold is transferred to air through a heat exchanger, and the cold air is blown through ducting down to the cabinets below. In the Global Responsibility Report Walmart said the Mistral system uses less refrigerant gas, offers more energy savings, needs less maintenance and “is also much safer to operate in our stores.” The 2017 University of Birmingham report, “Retail Refrigeration: Making the Transition to Clean Cold,” said that Asda had converted a dozen of its stores to Mistral, with one store reporting energy savings of 33%. The stores used R407 refrigerant, though the system could operate with any natural refrigerant, it said. MG

September 2019 // Accelerate Magazine

Profile for shecco

Accelerate Magazine #103 - September 2019  

With special coverage of HFO refrigerants, the September 2019 edition of Accelerate Magazine examines the potential long-term environmental...

Accelerate Magazine #103 - September 2019  

With special coverage of HFO refrigerants, the September 2019 edition of Accelerate Magazine examines the potential long-term environmental...

Profile for shecco