Thermal investigation of a micro-gap thermionic power generator

Remi Yacine Belbachir, Zhonglie An, Takahito Ono

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)


The demand for safe and clean energy sources has become more important than ever worldwide. Thermionic power generation is one of these energy sources, which directly converts heat into electrical energy using thermionic electrons. We developed a micro-gap thermionic power generator, which operates at relatively low temperature using SiC as an emitter. Electrons are emitted and travel from the heated SiC emitter to the collector electrode by thermionic emission. In this work, we have firstly demonstrated low temperature operation at 830 oC as a result of micro-gap between the emitter and collector electrodes. An output power density of 11.5 mW/cm2 is obtained. In addition, the heat losses from the emitter electrode are evaluated. Thermal conduction to the collector is by far the predominant thermal loss. In order to validate this result, a thermal resistance measurement device is built and the thermal resistance of the micro-gap is measured. Its value of 2.4 K/W allows for estimating in a more realistic way the heat loss by thermal conduction from the emitter to the collector via the gap. The newly estimated value still corresponds to a predominant thermal loss, hence highlighting the need for downsizing the SiO2 columns of the micro-gap in order to increase the power conversion efficiency.

Original languageEnglish
Article number085009
JournalJournal of Micromechanics and Microengineering
Issue number8
Publication statusPublished - 2014 Aug 1


  • SiC emitter
  • heat transfers
  • micro-gap
  • thermal resistance measurement
  • thermionic power generation


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