SOFC stacks respond quickly to changes in load and exhibit high part- and full-load efficiencies (due to rapid electrochemistry), which is not true for the balance of plant (BOP), where load-following time constants are several orders of magnitude higher. This dichotomy diminishes the reliability and performance of the electrode with increasing demand of load. Because these unwanted phenomena are not well understood, the manufacturers of SOFC use conservative schemes to control stack responses to load variations, which limit the applicability of SOFC systems from a cost standpoint. Thus, a need exists for the synthesis of component- and system-level models of SOFC power-conditioning systems and the development of methodologies for investigating the system-interaction issues (which reduce the lifetime and efficiency of a SOFC) and optimizing the responses of each subsystem. Equally important are “multiresolution” finite-element modeling and simulation studies that can predict the impact of changes in system-level variables (e.g., current ripple and load-transients) on the local current densities, voltages, and temperature (these parameters are very difficult or cumbersome, if not impossible to obtain) within a SOFC cell. Towards that end, this paper presents a design methodology (with illustrations) for a simulation tool that will enable comprehensive analyses of above (critical) issues.

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