M. Tech. (Engineering Department Applied Electronics and Electronic Communication, Faculty of Engineering) Vaal University of Technology / This study presents the design of a proton exchange membrane fuel cell stack that can
be used to replace conventional sources of electrical energy in an uninterruptible
power supply system, specifically for use in the telecommunications industry. One of
the major concerns regarding the widespread commercialization of fuel cells is the high
cost associated with fuel cell components and their manufacturing. A fuel cell design is
presented in which existing, low-cost, technologies are used in the manufacture of cell
components. For example, printed circuit boards are used in the manufacturing of
bipolar flow plates to significantly reduce the cost of fuel cells.
The first objective was to design, construct and test a single fuel cell and small fuel
cell stack in order to evaluate the use of printed circuit boards in bipolar plate
manufacturing. Since the use of copper in a fuel cell environment was found to reduce
the lifetime of the cells, the bipolar plates were coated with a protective layer of nickel
and chrome. These coatings proved to increase the lifetime of the cells significantly.
Power outputs of more than 4 W per cell were achieved.
The second objective was to analyze a small fuel cell stack in order to obtain a model
for predicting the performance of larger stacks. A mathematical model was developed
which was then used to design an electronic circuit equivalent of a fuel cell stack. Both
models were adapted to predict the performance of a fuel cell stack containing any
number of cells. The models were proven to be able to accurately predict the
performance of a fuel cell stack by comparing simulated results with practical
performance data.
Finally, the circuit equivalent of a fuel cell stack was used to evaluate the capability of
a switch mode boost converter to maintain a constant voltage when driven by a fuel
cell stack, even under varying load conditions. Simulation results showed the ability of
the boost converter to maintain a constant output voltage. The use of supercapacitors
as a replacement for batteries as a secondary energy source was also evaluated.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:vut/oai:digiresearch.vut.ac.za:10352/286 |
| Date | 01 1900 |
| Creators | Du Toit, Johannes Paulus |
| Contributors | Pienaar, H. C. v Z. |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | xii, 75 leaves: illustrations |
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