Design and optimization of Nano-catalytic energy cell as a portable power source

• Author / Creator

  Baladi, Arash

• Catalytic nanoburning (CNB) of methanol vapor using platinum nanoparticles on a thermoelectric (TE) module is a simple method for converting chemical energy into electrical power. Despite the many advantages of integrated nanoburning and thermoelectric modules, continuous power generation using this method is a challenge. CNB is a two-step process whereby platinum particles ignite the methanol, raising the particle temperature. This is followed by the auto-combustion of methanol in the region near the heated particles. When the catalyst is directly integrated with a thermoelectric generator, the capillary condensation of byproduct water at the particle-particle and particle-support interfaces progressively reduces the catalyst surface area, and in turn, lowers their catalytic activity. We show that the heat transfer coefficient value of the medium between the Pt-loaded substrate and the TE generator plays a critical role in achieving the optimum catalyst surface temperature and generated voltage by the TE device. A systematic investigation of various heat transfer media shows that very high thermal conductivity and heat transfer coefficient has a detrimental effect on power generation, as the catalyst surface temperature does not attain sufficiently high values owing to excessive conductive heat dissipation. This leads to elimination of thermal gradient, which is required when TE device is used to generate output voltage and power, and water condensation on the catalyst in case of very high conductive heat loss. Very low thermal conductivity and heat transfer coefficient are also undesirable due to poor heat transfer to the thermoelectric element, resulting in the very low output voltages and powers. Controlling the heat transfer mechanisms to the TE device can
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  maintain a high uniform surface temperature to eliminate water condensation while sustaining a constant thermal gradient across the TE generator. Heat conduction simulations corroborate this observation and provide predictions of the heat transfer coefficient, thermal conductivity, and thickness of the heat transfer medium that can optimize the performance of the device. We demonstrate a device having a sustained output power of ~285 mW at 1.053 V using 225 sccm flow rate of air-methanol mixture.

• Subjects / Keywords

  • Thermoelectric generator
  • Portable power generation
  • Catalytic combustion
  • Pt nanoparticle catalyst
  • Methanol combustion

• Graduation date

  Fall 2014

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R33N20M62

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.