Type of Document Master's Thesis Author Shevock, Bryan Wesley URN etd-01302008-170258 Title System Level Modeling of Thermal Transients in PEMFC Systems Degree Master of Science Department Mechanical Engineering Advisory Committee
Advisor Name Title Nelson, Douglas J. Committee Chair Ellis, Michael W. Committee Member von Spakovsky, Michael R. Committee Member Keywords
- Fuel Cell
- Polymer Electrolyte Membrane
Date of Defense 2007-01-28 Availability unrestricted AbstractFuel cell system models are key tools for automotive fuel cell system engineers to
properly size components to meet design parameters without compromising efficiency
by over-sizing parasitic components. A transient fuel cell system level model is being
developed that includes a simplified transient thermal and parasitics model. Model
validation is achieved using a small 1.2 kW fuel cell system, due to its availability. While
this is a relatively small stack compared to a full size automotive stack, the power,
general thermal behavior, and compressor parasitics portions of the model can be
scaled to any number of cells with any size membrane area. With flexibility in
membrane size and cell numbers, this model can be easily scaled to match full
automotive stacks of any size.
The electrical model employs a generalized polarization curve to approximate system
performance and efficiency parameters needed for the other components of the model.
General parameters of a stack’s individual cells must be known to scale the stack
model. These parameters are usually known by the time system level design begins.
The thermal model relies on a lumped capacity approximation of an individual cell
system with convective cooling. From the thermal parameters calculated by the model,
a designer can effectively size thermal components to remove stack thermal loads.
The transient thermal model was found to match experimental data well. The steady
state and transient sections of the curve have good agreement during warm up and cool
In all, the model provides a useful tool for system level engineers in the early stages of
stack system development. The flexibility of this model will be critical for providing
engineers with the ability to look at possible solutions for their fuel cell power
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