Analysis of a molten carbonate fuel cell: cogeneration to produce electricity and cold water

The fuel cell is an emerging cogeneration technology that has been applied successfully in Japan, the USA and some countries in the European Union. Th is system performs direct conversion of the chemical energy of the oxidatio n of hydrogen from fuel with atmospheric oxygen into direct current electri city and waste heat via an electrochemical process relying on the use of di fferent electrolytes (phosphoric acid, molten carbonate and solid oxide, de pending on operating temperature). This technology permits the recovery of waste heat, available from 200 degreesC up to 1000 degreesC depending on th e electrolyte technology, which can be used in the production of steam, hot or cold water, or hot or cold air, depending on the associated recuperatio n equipment. In this paper, an energy, exergy and economic analysis of a fu el cell cogeneration system (FCCS) is presented. The FCCS is applied in a s egment of the tertiary sector to show that it is a feasible alternative for rational decentralized energy production under Brazilian conditions. The t echnoeconomic analysis shows a global efficiency or fuel utilization effici ency of 86%. Analysis shows that the exergy losses in the fuel cell unit an d the absorption refrigeration system are significant. Furthermore, the pay back period estimated is about 3 and 5 years for investments in fuel cells of 1000 and 1500 US$/kW, respectively. (C) 2001 Elsevier Science Ltd. All r ights reserved.