United States.
The deployment of a CO2/ammonia cascade refrigeration system has helped a supermarket in Columbus, Georgia, obtain the highest EPA status: GreenChill Platinum. The Piggly Wiggly store, which recently opened, was built through close cooperation with Kysor/Warren, a division of Heatcraft Worldwide Refrigeration.
According to the EPA, a typical U.S. supermarket leaks approximately 1,000 pounds of harmful refrigerant gas into the atmosphere each year. The GreenChill Platinum certified store reduces those emissions by at least 95%. This warehouse is said to go further by reducing its annual global warming impact to just a fraction of 1% of a traditional store, using HFC refrigerants.
The cascade cooling system design uses ammonia and carbon dioxide as refrigerants in a cascade run. Through the Kysor/Warren design they have reduced the amount of ammonia refrigerant to just 3/4 pounds per ton of refrigeration for a total of 53 pounds, all of which are confined to the supermarket rooftop. Minimizing ammonia load eliminates the need for on-site engineers and other requirements typically associated with ammonia applications.
In addition to providing significant benefits in direct emissions, Kysor/Warren says its NH3/CO2 cascade system can provide significant energy savings compared to traditional transcritical HFC and CO2 systems in many climates. The cascade system design is also highly configurable and can be designed with other secondary refrigerants to meet individual retailer preferences.
