MULTIPHYSICS MODELING OF FUEL CELLS
Can Özgür Çolpan
Department of Mechanical Engineering
Dokuz Eylul University
Fuel cells are electrochemical devices that convert the energy in the fuel into electricity with high efficiency and low environmental impact. There are different types of fuel cells, which can be categorized according to their operating temperature level. In this study, the modeling of a low temperature fuel cell type, namely Flowing Electrolyte-Direct Methanol Fuel Cell (FE-DMFC), and a high temperature fuel cell type, namely Solid Oxide Fuel Cell (SOFC) will be discussed.
FE-DMFC is a novel low temperature fuel cell type in which a flowing electrolyte (e.g. diluted sulfuric acid) is pumped to the cell to reduce the methanol crossover through the membrane. A model has been developed to characterize the performance of this fuel cell. In this model, methanol, water, and oxygen transport equations are integrated with the electrochemical relations. The effects of the operating parameters (such as electrolyte flow rate, flowing electrolyte channel thickness, and methanol concentration at the feed stream) on the performance characteristics of the cell (including concentration distribution of the species, cell voltage, power density, and electrical efficiency of the cell) will be discussed.
SOFC is a high temperature fuel cell that can be designed to operate in temperatures ranging from 500 °C to 1000 °C. Several models at cell level including a thermodynamic model, a carbon deposition model, a 2-D transient heat transfer model, and a thermo-mechanical model of a direct internal reforming SOFC have been developed. The first two models are based on the principles of thermodynamics and electrochemistry; whereas in the other models, the conduction, convection, and radiation heat transfer equations are coupled with the electrochemical relations to find the performance of a cell at the heat-up and start-up stages of the SOFC. In addition, an innovative integrated SOFC and biomass gasification systems will be introduced. The effects of the gasification agent (air, enriched oxygen and steam), rotational speed of the pyrolysis reactor, number of SOFC stacks, and the moisture content of the biomass on the output parameters will be discussed.
C. Ozgur Colpan is currently an Associate Professor at the Mechanical Engineering Department of Dokuz Eylul University in Izmir. He received his PhD Degree (2009) from Carleton University in Ottawa, Canada and his Bachelor of Science (2003) and Master of Science (2005) Degrees from the Middle East Technical University in Ankara. His research areas include the modeling of electrochemical systems such as fuel cells and batteries, and exergy and thermoeconomic analyses of integrated energy systems.