New U.S. cold stores feature CO₂ cascade refrigeration

Two new United States Cold Storage distribution centres, set to start operating in summer 2009, will employ CO₂ cascade refrigeration technology bringing to four the number of the company facilities already featuring such technology.

CO₂ cascade refrigeration technology is employed at a high-volume distribution centre in Lebanon, Indiana, which the public refrigerated warehousing (PRW) company United States Cold Storage (USCS) will start operating this July. The $38 million facility, offering a complete line of services from product storage to custom order handling and local area delivery, will feature:

• CO₂ cascade refrigeration technology
• convertible temperature rooms
• an enclosed shipping/receiving dock
• more than 24,000 variable-height pallet positions in temperatures ranging from -20° to +55° F (-28.9 to 12.8˚C)
• a 30-truck dock will provide access to a 65-foot-wide temperature-controlled area for loading and unloading goods

USCS continues to pursue a policy of aggressive investment in the modernisation of existing facilities and the construction of new refrigerated centers at carefully selected distribution locations. The distribution centre in Lebanon is the fourth USCS facility to employ CO₂ cascade refrigeration technology, with the other three being located in California, Pennsylvania and Florida. The company has made R744 systems the technology of choice to improve operating efficiency and reduce the impact on the environment.

Meanwhile, USCS is expanding its facilities in California with a 5 million cubic foot facility located in Turlock, which is also scheduled for completion in summer 2009. The facility will feature a state-of-the-art cascade CO₂/NH₃ refrigeration system to maintain +35ºF to -20ºF temperatures.

The first PRW using R744/R717 cascade system

A USCS facility in Pennsylvania was the first PRW in the US to use a combination of carbon dioxide and ammonia in a cascade refrigeration system. By combining CO₂ and NH₃, and employing efficient heat exchangers, the ammonia charge was greatly reduced and confined within the machinery room. This system offers lower operating costs at temperatures typically used for blast freezing compared to more traditional modes of refrigeration. Using R744 as the low side refrigerant and R717 as the high side refrigerant, the operating pressures can be kept at a relatively low level, and allows suction pressures to go as low as -65˚F (-53.8˚C) more efficiently than ammonia. The ammonia system is only used to condense the CO₂ gas in the CO₂ system.

M&M Refrigeration, Inc. of Federalsburg, Maryland, collaborated closely with USCS to design the system in Pennsylvania, where two ammonia screw and two CO₂ reciprocating compressor packages handle the entire load. CO₂ is pumped to evaporator coils in four freezers as well as to truck and rail loading docks. Room temperatures can on command be kept as low as -20˚F (-28˚C) in the freezers and between +35˚F (1.6˚C) and +50˚F (10˚C) on loading docks. Two of the freezers are convertible and can be switched from freezer to cooler mode. M&M Refrigeration was the one who also supplied the CO₂ refrigeration system in the Lake City, Florida, USCS facility.

About United States Cold Storage and M&M Refrigeration

USCS is among the top five largest PRWs in the USA, offering more than 170 million cubic feet of temperature-controlled warehouse and handling space in 31 facilities located in ten states, while it employs approximately 1,500 highly trained service professionals. USCS is wholly-owned by John Swire & Sons, founded in 1816 and headquartered in London, England.

M&M Refrigeration, Inc. is a "Total Solutions" provider of industrial refrigeration equipment and controls, including CO₂ compressor packages.