Process Analysis and Evaluation of Exergy Loss in Solid Oxide Fuel Cell

A solid oxide fuel cell (SOFC) is expected to be applied to the distributed energy systems because of its high thermal efficiency and exhaust gas utilization. The exhaust heat from the SOFC can be transferred to the electric power by a gas turbine and the high efficiency power generation can be achieved. In this paper, the local processes in electrodes and electrolyte of unit SOFC are analyzed taking into account the heat conduction, mass diffusion, electrode reactions and transport of electron and oxygen ion. The temperature and concentration distributions in electrodes and electrolyte membrane are investigated. The effects of operating conditions on the cell performance are also shown. Furthermore, the entropy generation and exergy loss of each process are analyzed and the reason for generating the exergy loss in the SOFC is clarified. It is noted that two electrode reactions are responsible for the major exergy loss.