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Temperature regulation in an evaporatively cooled proton exchange membrane fuel cell stack
Maintaining proton exchange membrane fuel cell (PEMFC) stack operating temperature across transient current profiles presents a significant challenge for fuel cell vehicles. Liquid cooled systems require active control of coolant temperature and flow rate to match heat rejection to heat generation. Evaporative cooling is an alternative to conventional liquid cooling in automotive sized PEMFC stacks. In an evaporatively cooled system, liquid water is injected directly into the cathode flow channels where it evaporates, both cooling and humidifying the stack. This paper uses a validated simulation to explore the inherent temperature regulation abilities of an evaporatively cooled PEMFC stack across a range of current profiles and drive cycles. Results show that throughout the normal operating current range, stack temperature varies by less than±2.0°C, this is comparable to liquid cooling but without the need for active temperature control. The introduction of variable operating pressure and cathode stoichiometry using proportional integral control, can further reduce temperature variation to±1.0°C and±1.2°C respectively for step increases in current demand. Variable operating pressure is also shown to improve warm up time and reduce heat loss at low operating loads.
Funding
The authors would like to acknowledge the support of the EPSRC and the Doctoral training centre in hydrogen fuel cells and their applications, grant number EP/G037116/1.
History
School
- Aeronautical, Automotive, Chemical and Materials Engineering
Department
- Aeronautical and Automotive Engineering
Published in
International Journal of Hydrogen EnergyCitation
FLY, A. and THRING, R.H., 2015. Temperature regulation in an evaporatively cooled proton exchange membrane fuel cell stack. International Journal of Hydrogen Energy, 40(35), pp.11976-11982.Publisher
© The Authors. Published by Elsevier Ltd on behalf of Hydrogen Energy Publications, LLC.Version
- VoR (Version of Record)
Publisher statement
This work is made available according to the conditions of the Creative Commons Attribution 4.0 International (CC BY 4.0) licence. Full details of this licence are available at: http://creativecommons.org/licenses/ by/4.0/Publication date
2015Notes
This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).ISSN
0360-3199Publisher version
Other identifier
S0360-3199(15)00998-2Language
- en