Industrial refrigeration
SEIZING THE NH3 /CO2 OPPORTUNITY
Rendering of new Lineage Logistics facility in Charleston, S.C.
For its new Charleston, S.C., plant, Lineage is installing a cascade NH3/CO2 system that is gaining popularity for cutting ammonia charge while operating very efficiently – By James Ranson
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here are big changes afoot in the North American industrial refrigeration business, as systems that use far less ammonia than conventional setups are gaining considerable traction. Add Lineage Logistics, one of the nation’s largest coldstorage providers, to the list of companies going in this direction. Next March Lineage, which operates 110 warehouses in the U.S. encompassing over 600 million cubic feet, plans to unveil a refrigerated warehouse in Charleston, S.C., that will be its first to employ a cascade ammonia/carbon dioxide refrigeration system in lieu of a traditional two-stage ammonia system to blast freeze product from 30-40°F down to 0°F. The reasons for this are many, but chief among them: NH3/CO2 systems dramatically cut ammonia charge, improving safety while exempting operators from most ammonia regulations. Moreover, economies of scale are bringing down the cost of NH3/CO2 systems, and
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for facilities like Lineage’s relying on blast freezing, these systems have proven to be very efficient.
Bethlehem, Pa., facility has 6,400 pounds of ammonia and 48,000 pounds of CO2 in the cascade setup.
Another large cold-storage operator, US Cold Storage, can be credited with bringing the NH3/CO2 system to the fore in 2005, when that technology was virtually unheard of. Since then the company has established many industry standards when it comes to NH3/CO2 installations, with 11 of its 35 public refrigerated warehouses operating this system. (See “Shaking Up Industrial Refrigeration,” Accelerate America, April 2015.)
Lineage’s 180,262-square-foot Charleston facility will contain 7,969 pounds of ammonia and 60,111 pounds of CO2. (The ammonia side serves only as a condenser and to reject heat from the CO2 system.) This will accommodate 2,191 tons of refrigeration capacity across 646,160 cubic feet of storage. By contrast, a traditional two-stage pump-recirculated ammonia system typically contains between 40,000 and 50,000 pounds of ammonia.
Overall, there are now 53 NH3/CO2 cascade systems installed in industrial facilities in the U.S., eight in Canada and eight in Mexico, according to the 2015 GUIDE to Natural Refrigerants in North America. Ten of US Cold Storage’s systems are cascade models, using low-temperature CO2 compressors, while one, in Quakertown, Pa., uses a critical brine solution with CO2 circulated as a secondary refrigerant. Its
Accelerate America October 2015
SIGNIFICANT UPTAKE FOR NH3/CO2 Matt Hirsch, president of Primus Builders, Woodstock, Ga., which, together with Republic Refrigeration, is installing Lineage’s NH3/CO2 system, has the benefit of hindsight on its side. Primus has completed seven of US Cold Storage’s NH3/CO2 installations, including the most recent one in Covington, Tenn. “It’s true, we’ve seen a significant uptake for NH3/