Can carbon dioxide and ammonia work together? Apparently so, according to Mark Tomooka of Mayekawa in the US.

In his conference presentation, Tomooka described the company’s NH₃/C0₂ solutions for the supermarket industry, in which ammonia charge is kept below 250 pounds.

One system was installed in a SuperValue store in the town of Carpinteria in California in 2012 that is described as the first “all natural” supermarket in the US.

Tomooka said the Carpinteria project proved a low-charge ammonia system can be competitive with other systems.

"This store is seeing efficiency gains of 13 to 30 per cent,” he said.

He said there are signs the market for natural refrigerants in the US is maturing.
These signs include the development of standards such as the Underwriters’ Laboratories (UL) approval for C0₂ transcritical compressors and a pending update to ASHRAE standard 15, which will include C0₂ transcritical options.

CIMCO Refrigeration presented a case study demonstrating a successful ammonia/CO₂ refrigeration system deployment at Canadawide, one of the country’s largest distributors of fruit and vegetables.

The system has saved Canadawide nearly 20 per cent in maintenance costs, with even more significant reductions in operating costs.

Danfoss vice president of public affairs, Robert Wilkins, said no single refrigerant is suitable for all applications.