Ammonia refrigeration takes several forms at Seafood Expo

A variety of ammonia refrigeration applications, from cold storage to quick-freezing to ice making, were showcased at the Seafood Expo North America/Seafood Processing North America shows, co-located at the Boston Convention and Exhibition Center last week. A growing trend is the use of ammonia-carbon dioxide systems, which reduce the ammonia charge and improve safety.

NH₃-CO₂ systems gaining traction

Mayekawa’s freezer division, which markets process freezers that quick-freeze seafood products was at the Seafood Expo as part of its effort to enter the North American market. (Its refrigeration division is already well established in North America.)

While most of Mayekawa’s end users employ ammonia in quick-freeze applications, closed ammonia-CO₂ systems are being more widely used.

“Processors want to eliminate ammonia in the processing area and use CO₂ there,” said Bud Martinson, Mayekawa’s sales manager, freezer division. “The ammonia can then be isolated in the refrigeration room.” The dual-refrigerant system also can go to lower temperatures.

Unusual ammonia condensing unit for ice maker

Chicago-based Howe Corp.’s industrial ice flake makers typically tie into a facility’s ammonia refrigeration system or to a dedicated condensing unit using an HFC (hydrofluorocarbon) gas. However, two years ago, Freshwater Fish Marketing installed a 20-tons-per-day ice flake maker linked to a dedicated condensing unit using ammonia. “It’s unusual to put in a condensing unit with ammonia to run an ice machine,” said Andrew Ortman, Howe’s vice president, sales & marketing. The reason for that is the ammonia condensing unit requires steel rather than copper piping, boosting the cost.

Colmac Coil, Colville, Wash., promoted its reverse-air ammonia blast freezer, designed to reduce freezing time and improve product quality, said CEO Scott McMillan.

It uses computer simulation to determine the “best air-flow pattern” for maximum freezing, he added.

Ammonia-CO₂ systems growing in popularity

Lineage Logistics, Richmond, Va., a six-year-old company that has grown its network of 111 temperature-controlled warehouses through the acquisition of 16 companies, recently began installing ammonia/CO₂ refrigeration systems, in lieu of ammonia-only or HFC refrigeration, in a few of its newer facilities.

The lower ammonia charge in the ammonia/CO₂ system brings a facility under the federal reporting threshold and minimises the impact of an ammonia leak, noted Scott Chapman, vice president, industry relations.

Skaginn, based in Iceland, also offers ammonia/CO₂ refrigeration systems. Its latest customer for this technology is Eastern Fisheries, which uses a closed-loop mechanical system for an IQF (individually quick freeing) application, said Sigurour Skulason, sales and service. The system combines frosting and freezing.

“It’s a new refrigeration system in an existing plant,” he said. “They took out a nitrogen (cryogenic) system and put in an ammonia/CO₂mechanical freezer.” He said this type of transition is ‘unusual’.”

Because of their lower running costs, ammonia/CO₂ systems are “getting popular” for cold-temperature applications, he said. Other customers have been using ammonia/CO₂ for a few years in plate freezers.