SOFC mathernatic model for systems simulations. Part one: from a micro-detailed to macro-black-box model

The aim of the present work is to assess the requirements of an SOFC mathematic model for system simulation. Several models can be found in the literature to predict fuel cells electrochemical and then-no-fluid-dynamic characteristics, but these models are generally based on local characteristics, such as gas concentration, temperature, pressure and so on. The equations representing these characteristics can be in a finite or differential form, but, in any case, they are locally solved using a mesh. The obtainable results can be very useful to guide future researches for FC improvements and optimization. On the other hand, most of these data are useless if the FC system has to be modeled. In this situation, in fact, what is necessary for mathematic modeling are just the discharge characteristics, such as outlet gas composition and temperature, the electric current and power provided. Moreover, calculations for micro-model solution imply numerical methods that are often complex and time consuming. Since during FC systems parametric analyses, the FC characteristics can be computed up 2 hundred times, the need for an easy model is crucial. In applying the local equations as "global", however, some problems can arise. In the present work, a review of the most significant SOFC models is conducted and then the possibility of their use in a macro-model is evaluated. Different results can be generated according to the assumptions made when adapting micro-model equations to a macro-model. A quantitative analysis of these differences is finally performed and the reliability of the model is estimated. (C) 2004 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.