Cascade system earns highest GreenChill status

USA: The deployment of an ammonia/CO2 cascade refrigeration system has helped a supermarket in Columbus, Georgia, achieve the EPA’s highest GreenChill platinum status.

The Piggly Wiggly store, opened on Wednesday, was built through a close co-operation with Kysor/Warren, a division of Heatcraft Worldwide Refrigeration.

According to the EPA, a typical US supermarket leaks approximately 1,000lbs of harmful refrigerant gas into the atmosphere every year. GreenChill Platinum Certified Stores reduce those emissions by at least 95%. This store is said to go further by reducing its annual global warming impact to only a fraction of 1% of a traditional store using HFC refrigerants.

The cascade refrigeration system design utilises ammonia and carbon dioxide as refrigerants in a cascade arrangement. Through innovative design, Kysor/Warren has reduced the amount of ammonia refrigerant to only 3/4lb per ton of refrigeration totalling 53lbs, all of which is confined to the roof of the supermarket. Minimising the ammonia charge eliminates the need for on-site engineers and other requirements typically associated with ammonia applications.

In addition to providing significant direct emissions benefits, Kysor/Warren says its NH3/CO2 cascade system can provide significant energy savings versus both traditional HFC systems and CO2 transcritical systems in many climates. The cascade system design is also highly configurable and can be designed with other high-side refrigerants to meet individual retailer preferences.

“As environmental impact and sustainability have gained attention, many retailers are turning to us to ensure they have the most sustainable refrigeration systems possible,” states Michael Lehtinen, marketing director for Kysor/Warren. “We are working with our customers to implement market-leading HFC-free solutions to ensure that we not only help our customers minimize environmental footprint, but also maximize savings and operational benefits.”

In addition to using “natural” refrigerants, the refrigeration system also employs energy recovery to provide hot water. The store features several other energy-saving features, including skylights and LED ambient lighting throughout the store and doors on all beverage, preserved meat and dairy refrigerated cases.