Mathematical models are important tools for studying complex systems such as fuel cell devices. The aim of this work is to develop electrochemical model for intermediate temperature solid oxide fuel cells (IT-SOFCs) in order to investigate the whole fuel cell processes and the operating condition effects. In this way it is possible to select the optimal conditions leading to the highest cell performances. the investigation is focussed on the main factors affecting the cell performances, such as working temperature, the component thickness and the porosity. In addition, the exergetic analyses provide the contribution of every overpotential on cell voltage degradation. Copyright © 2013 Delta Energy and Environment.