Industrial operators look to CO₂ in plant expansions

CO₂ is becoming a growing refrigeration add-on option for cold-storage and food processing operators that are expanding their ammonia-based operations, said an account executive for M&M Refrigeration, a leading supplier of ammonia/CO₂ cascade systems, in an exclusive interview yesterday.

The CO₂ in these scenarios is used as the cooling agent, with ammonia serving to condense the CO₂ in what is known as an ammonia/CO₂ cascade system.

Since 2004, M&M, based in Federalsburg, Md., has installed more than 55 ammonia/CO₂ systems in North and Central America and Southeast Asia, said Todd Donohoe, the account executive, in an interview yesterday at the Global Cold Chain Expo at McCormick Place in Chicago.

Asked about the growth of the market for ammonia/CO₂ systems, he said M&M cold-storage operators planning to add a frozen room to an existing facility may initially inquire about a standard single-stage or two-stage ammonia system. “We say, ‘Have you thought about CO₂, because it can save you money in the long run,’” said Donohoe. “That’s where the conversation usually starts.”

When installing CO₂ in an expansion, M&M sometimes uses the existing ammonia engine room to condense the CO₂ in a cascade heat exchanger, and sometimes adds additional ammonia equipment. “If there’s no room in the existing engine room, we can do a self-supporting skid outside,” he said.

In a current expansion scenario, M&M is converting the entire plant to CO₂, using ammonia only in the engine room to condense the CO ₂, said Donohoe, who declined to name the operator without its permission. “We are repurposing the existing ammonia screw compressors, using different motors, and adding CO₂ reciprocating compressors.”

CO₂/NH₃ cascade technology is a compelling option for industrial operators employing blast or spiral freezers because it uses smaller line sizes than ammonia, is easier to install, and reduces the ammonia charge – “all the buzzwords,” said Donohoe. Moreover, the cascade systems are up to 35% more efficient than a two-stage ammonia system at -58°F saturated suction temperature, he noted.