Exergy Analysis of a Molten Carbonate Fuel Cell-Turbo Expander-Steam Turbine Hybrid Cycle

Exergy analysis of an integrated molten carbonate fuel cell-turbo expander-steam turbine hybrid cycle has been presented in this study. The proposed cycle has been used as a sustainable energy approach to provide a micro hybrid power plant with high exergy efficiency. To generate electricity by the mentioned system, an externally reformed molten carbonate fuel cell located upstream of the combined cycle has been used. Furthermore, the turbo expander and steam turbine systems have been considered as topping and bottoming cycles for the purpose of cogeneration, respectively. Results show that the proposed system is capable of reaching a net delivered power of 1125 kW, while the total exergy efficiency (including both electricity and heat) of this system is more than 68%. Moreover, the delivered power and exergy efficiency from the proposed cycle is stable against ambient temperature variations. In addition, the effect of a current density increase on cell voltage and total exergy destruction has been considered.