Cycle Analysis using Exhaust Heat of SOFC and Turbine Combined Cycle by Absorption Chiller

The power generating efficiency of solid oxide fuel cell (SOFC) and gas turbine combined cycle is fairly high. However, the exhaust gas temperature of the combined cycle is still high, about 300°C. Thus, it should be recovered for energy saving, for example, by absorption chiller. The energy demand for refrigeration cooling is recently increasing year by year in Japan. We propose here a cogeneration system by series connection of SOFC, gas turbine and LiBr absorption chiller to convert the exhaust heat to the cooling heat. As a result of cycle analysis of the combined system with 500-kW-class SOFC, the bottoming single-effect absorption chiller can produce a refrigerating capacity of about 120 kW, and the double-effect absorption chiller can produce a little higher refrigerating capacity of about 130 kW without any additional fuel. But the double-effect absorption chiller became more expensive and complex than the single-effect chiller. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(1): 49– 55, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20578