Performance assessment of a hybrid system integrating a molten carbonate fuel cell and a thermoelectric generator

A hybrid system consisting of an MCFC (Molten Carbonate Fuel Cell), a TEG (Thermoelectric Generator) and a regenerator is proposed. In this system, the MCFC produces electricity and heat from fuels and the TEG utilizes the heat for additional power generation. A numerical model is developed to evaluate the performance of the proposed system. The relationship between the operating current density of the MCFC and the dimensionless current of the TEG is theoretically derived and the operating current density region of the MCFC that allows the TEG to function is determined. Numerical expressions of the power output and efficiency for the hybrid system are specified under different operating conditions. The general performance characteristics and optimum criteria for the hybrid system are revealed. It is found that the hybrid system is superior to the stand-alone MCFC system as the bottoming TEG can effectively increase the maximum power density. In addition, the effects of the operating current density, operating temperature, operating pressure, heat conductivity, integrated parameters and dimensional figure of merit on the performance characteristics of the hybrid system are investigated. The results obtained are useful for the design and optimization of novel MCFC system to achieve a better performance.