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In the first part of the study, we present a model of the solid oxide fuel cell (SOFC) system with anode off-gas recirculation (AGR) in the SchIBZ-project. In this last second paper, we conduct an exergy analysis of this real SOFC plant, using validated models for the reformer and the SOFC module from our first study. We find that an optimum recirculation and low O / C -ratios yield a high exergetic efficiency, due to the small exergy losses in the conversion of chemical energy to electrical power in the SOFC-module under these operation conditions. We conduct our simulations based on a real concept and use validated models, so that the exergy analysis given in this work may be a reliable estimate to the real thermodynamic behavior of this SOFC plant. • The efficiency of the fuel cell system of the well-known SchIBZ project is analysed. • An exergy analysis depending on the recirculation rate and O/C-ratio is conducted. • The SOFC model is successful validated within the system in part load. • The fuel cell characteristics are calculated with the validated model. [ABSTRACT FROM AUTHOR]

Solid oxide fuel cell (SOFC) systems with anode off-gas recirculation (AGR) and diesel pre-reforming are advantageous because they can operate with the current fuel infrastructure. In the SchIBZ-project, the prototype of such a SOFC system for maritime applications has already been commissioned. In this first paper, we model the system devices to conduct an exergy analysis of this real SOFC plant and validate them with experimental values from experiments in laboratory scale. The results of our simulation agree well with the experimental values. The calculations with the validated results may be closer to the real thermodynamic behavior of such system components than previous literature. [ABSTRACT FROM AUTHOR]

The calculation of the entropy production rate within an operational high temperature solid oxide fuel cell (SOFC) is necessary to design and improve heating and cooling strategies. However, due to a lack of information, most of the studies are limited to empirical relations, which are not in line with the more general approach given by non-equilibrium thermodynamics (NET). The SOFC 1D-model presented in this study is based on non-equilibrium thermodynamics and we parameterize it with experimental data and data from molecular dynamics (MD). The validation of the model shows that it can effectively describe the behavior of a SOFC at 1300   K . Moreover, we show that the highest entropy production is present in the electrolyte and the catalyst layers, and that the Peltier heat transfer is considerable for the calculation of the heat flux in the electrolyte and cannot be neglected. To our knowledge, this is the first validated model of a SOFC based on non-equilibrium thermodynamics and this study can be extended to analyze SOFCs with other solid oxide electrolytes, with perovskites electrolytes or even other electrochemical systems like solid oxide electrolysis cells (SOECs). [ABSTRACT FROM AUTHOR]