At NTT Power and Building Facilities, an air conditioning system is being developed that uses the exhaust heat from phosphoric acid fuel cells. This paper describes the operating characteristics of an absorption refrigerator that uses two types of waste heat recovered from fuel cells for year-round operation. The design combines a single-effect and a double-effect absorption refrigerator to make effective use of two heat sources as the heat level recovered from the fuel cells varies. To ensure year-round operation, the refrigerator is designed to function at cooling water temperatures as low as 15/spl deg/C. It can also efficiently use hot water between 65 and 85/spl deg/C recovered from the fuel cell's exhaust gas. The average yearly cooling capacity of this waste-heat driven machine designed for year-round operation is 30% greater than that of conventional absorption refrigerators. This increases to 50% when the low-temperature exhaust gas from the fuel cell is also used.
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