This work presents an experimental analysis of circular-planar type intermediate-temperature solid oxide fuel cells, and the interpretation of the experimental results with a finite volume model. The model is developed to generate cell mass and energy balances and internal cell profiles for all the relevant thermodynamic or electrochemical variables, and includes a fluid-dynamic analysis focusing on the investigation of the cell internal flow conditions. Experiments have been carried out at the Edison laboratories, where several single cells fuelled with hydrogen were subject to polarization curve analysis and internal temperature measurements. The model is calibrated and validated over experimental voltage-current data, provides information on cell internal losses and demonstrates the capacity of predicting the single cell behavior and overall energy balances when changing significantly the cell operating conditions. The discussion also addresses the effects of diffusion losses appearing in the experiments carried out at high current output and low fuel hydrogen content. (C) 2007 Elsevier B.V. All rights reserved.