Thesis (M. Tech. - (Engineering: Electrical, Department: Electronic Engineering, Faculty of Engineering and Technology)) -- Vaal University of Technology, 2011. / “Never before in peacetime have we faced such serious and widespread shortage of energy”
according to John Emerson, an economist and power expert for Chase Manhattan Bank.
Many analysts believe that the problem will be temporary, but others believe the energy gap
will limit economic growth for years to come. A possible solution to this problem can be fuel
cell technology. Fuel cells (FCs) are energy conversion devices that generate electricity from
a fuel like hydrogen. The FC however, could also be used in the reverse or regenerative
mode to produce hydrogen.
The reversible fuel cell (RFC) can produce hydrogen and oxygen by introducing water to the
anode electrode chamber, and applying a potential across the anode and cathode. This will
cause the decomposition of the water to produce oxygen at the anode side and hydrogen at
the cathode side. In order to make this process as efficient as possible several aspects need
to be optimised, for example, the operation temperature of the RFC, water management
inside the RFC and supply voltage to the RFC.
A three cell RFC and its components were constructed. The three cell RFC was chosen
owing to technical reasons. The design factors that were taken into consideration were the
different types of membranes, electrocatalysts, bipolar plates and flow topologies. A water
trap was also designed and constructed to eliminate the water from the hydrogen water
mixture due to water crossover within the MEA. In order to optimise the operation of the RFC
a number of experiments were done on the RFC. These experiments included the optimal
operating voltage, the effect that the temperature has on the production rate of hydrogen,
and the effect that the water flow through the RFC has on the production rate of hydrogen.
It was found that there is no need to control the water flow through the RFC because it had
no effect on the production rate of hydrogen. The results also showed that if the operating
temperature of the RFC were increased, the energy it consumes to warm the RFC
significantly decreases the efficiency of the whole system. Thus the RFC need not be heated
because it consumes significantly more energy to heat the RFC compared to the energy
available from the hydrogen produced for later use. The optimised operating voltage for the
three cell RFC was found to be 5.05 V. If the voltage were to be increased or decreased the
RFC efficiency would decrease.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:vut/oai:digiresearch.vut.ac.za:10352/111 |
| Date | 12 1900 |
| Creators | Van Tonder, Petrus Jacobus Malan |
| Contributors | Pienaar, HCvZ |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | xi, 76 leaves :|bill., diagr., graphs. (some col.) |
| Relation | PDF (Adobe Acrobat Reader) |
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