Waste Heat Recovery from Refrigeration in a Meat Processing Facility

Abstract

A case study is reviewed on a heat recovery system installed in a meat processing facility to preheat water for the plant hot water supply. The system utilizes waste superheat from the facility's 1,350-ton ammonia refrigeration system. The heat recovery system consists of a shell and tube heat exchanger (16"? x 14'0") installed in the compressor hot gas discharge line. Water is recirculated from a 23,000-gallon tempered water storage tank to the heat exchanger by a circulating pump at the rate of 100 gallons per minute. All make-up water to the plant hot water system is supplied from this tempered water storage tank, which is maintained at a constant filled level.

Tests to determine the actual rate of heat recovery were conducted from October 3, 1979 to October 12, 1979, disclosing an average usage of 147,000 gallons of hot water daily. These tests illustrated a varied heat recovery of from 0.5 to 1.0 million BTU per hour. The deviations were the result of both changing refrigeration demands and compressor operating modes. An average of 16 million BTU per day was realized, resulting in reduced boiler fuel costs of $30,000 annually, based on the present $.80 per gallon #2 fuel oil price. At the total installed cost of $79,000, including test instrumentation, the project was found to be economically viable. The study has demonstrated the technical and economic feasibility of refrigeration waste heat recovery as a positive energy conservation strategy which has broad applications in industry and commerce.