Comparison of thermal performances of external and internal reforming molten carbonate fuel cells using numerical analyses

The temperature, thermal stress distribution, and structural stability were compared to investigate the thermal effects in external and internal reforming molten carbonate fuel cell (MCFC) systems with a large active area. A computational fluid dynamic (CFD) analysis that considers electrochemical reactions is performed, and the thermal stresses using the temperature distributions are calculated. The heat transfer rate toward the anode side is slightly lower than that toward the cathode side in the external reforming MCFC. However, most of the internally generated heat is transferred toward the anode side due to the highly intensive endothermic process that occurs in the internal reforming MCFC. The electric power of the internal reforming MCFC is 3.2% lower than that of the external reforming MCFC, but the efficiency was 11% higher. Due to more uniform temperature and thermal stress distributions than the external reforming MCFC, the internal reforming MCFC is mechanically more stable, and thus, and extended lifespan can be expected for high-temperature operations.