Katie S. Howe Centre for Hydrogen and Fuel Cell Research SOFC Research group Dynamic Performance of Micro-Tubular Fuel Cells
Overview Starting Point –Fuel cells –Status of dynamic performance research Experimental Work Results Conclusions Next Steps
Starting Point: Fuel Cells Change electrochemical energy into useful electricity Like a battery, but not limited by how much fuel they can hold
Starting Point: Fuel Cells mSOFCs –Tubular –Better thermal shock resistance –Fewer issues with sealing
Starting Point: Research Status Load-following capability is vital for most real-world applications In the literature: Many papers on steady-state performance Some modelling work on dynamic behaviour [1-3] ...but hardly any experimental results [1] Nehter, P., 2006, Journal of Power Sources, 157(1), pp [2] Ota, T., Koyama, M., Wen, C. J., Yamada, Y., and Takahashi, H., 2003, Journal of Power Sources, 118(1-2), pp [3] Serincan, M. F., Pasaogullari, U., and Sammes, N. M., 2009, Journal of Power Sources, 194(2), pp
Starting Point: Research Status Thermal transport time dominates dynamics [4] Readjustment time independent of step size [5] Undershooting of voltage when current rises [5] –Size of undershoot related to step size [4] Bhattacharyya, D., and Rengaswamy, R., 2009, "A Review of Solid Oxide Fuel Cell (SOFC) Dynamic Models," Ind. Eng. Chem. Res., 48(13), pp [5] Achenbach, E., 1995, "Response of a solid oxide fuel cell to load change," Journal of Power Sources, 57(1-2), pp
Experimental Work - Method Single cells made to in-house techniques [6] – Operated at 750 C – Fuel: 20ml/minute of pure hydrogen Solartron TM analytical 1400 Cell Test System –Apply sets of square pulses of current Paper submitted [7] with precise details [6] Dhir, A., 2008, "Improved Microtubular Solid Oxide Fuel Cells," PhD Thesis, University of Birmingham, [7] Howe, K. S.; Kendall, K., Transient Performance of Micro-tubular Solid Oxide Fuel Cells. Journal of Fuel Cell Science and Technology 2010,.Paper Accepted – awaiting editorial changes
Results Transient behaviour:
Results
Conclusions Short re-adjustment time of <0.5s is independent of step size –Agreement with models in the literature No under-shooting of voltage on the change –Suggests thermal transport is better than expected in these tubes
Next Steps Combination of cells into small stacks –Higher powers –Dynamic performance testing of stacks Effects of changing to a hydrocarbon fuel on transient performance
Acknowledgements With thanks to... My supervisors: Kevin Kendall and Stephen Decent My sponsors: RCUK and EADS Innovation Works
Thank you! Any questions?