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The annual saving rates of primary energy and operating cost of NH 3 and CO 2 heat pumps for seven food processes in four characteristic locations with different energy prices in the U.S. are analyzed. The modeled food processes include beer brewing, food pasteurization, fluid milk processing, cheese processing, vegetable and fruit canning, juice canning, and poultry slaughtering. The investigation focuses on the effects of the characteristics of the thermal demands, the location of the proposed systems, and the energy price structure on the savings of primary energy and the operating cost. The results indicate that the characteristics of the thermal demands are the most crucial factor. The energy price structure significantly impacts the operating cost-saving rate. The analysis shows that the annual savings of primary energy can achieve 32% in food pasteurization, 44% in beer brewing, and 35% in fluid milk processing. [ABSTRACT FROM AUTHOR]

Food processing has significant simultaneous requirements of cooling, warm water and hot water. In order to reduce energy consumption and greenhouse gases emission, one type of NH 3 heat pump and two types of transcritical CO 2 heat pumps are proposed. These natural refrigerant heat pumps can supply not only cooling, but also warm water and hot water simultaneously. The characteristics and performance of the heat pumps are analyzed and simulated. Annual primary energy saving and annual operation cost saving are predicted for California, Wisconsin, New York, and Florida. Research results show that the maximum possible value of annual primary energy-saving rates using the CO 2 heat pumps ranges from 56% to 65%, and using the NH 3 heat pump is approximately 44%; the maximum possible value of annual operation cost saving rates using the CO 2 heat pumps ranges from 50% to 66%, and using the NH 3 heat pump is from 20% to 47%. [ABSTRACT FROM AUTHOR]