The concept of a secondary refrigeration system for high-temperature use was investigated in 1991, and a design for a full high-temperature system was completed the following year. In late 1992, a supermarket chain commissioned a study of the feasibility of turning the design into a practical application and assisted the project in 1993 by commissioning a test facility for single-temperature secondary refrigeration at one of the company's factory sites. Results and conclusions from this trial work pointed toward the need for a total secondary refrigeration system, including a low-temperature system for frozen food display cases, and the possibility of utilizing environmentally friendly ammonia as the primary refrigerant. Therefore, in late 1993/early 1994, a low-temperature system was developed and commissioned at the test facility. Full collaboration between the supermarket company and the contractor resulted in the funding of practical trial work and feasibility studies for both secondary refrigeration and a fully detailed proposal for the use of ammonia in a public retail environment. In May 1995, the first U.K. ammonia and two-level secondary refrigeration system began operation in a supermarket in Horsham, Sussex England.

Units: SI