Concentrated solar thermalProject Fabrication of Thermionic Device using Advanced Ceramics
Research on ways to improve the efficiency of materials for converting heat directly to electricity for Concentrated Solar Thermal technology, which also have prospects for mass production.
The primary learning relates to the synthesis and characterisation of electron emissive materials, design and construction of the high-temperature – high vacuum envelope and assembly of a working device. These were:
- High purity electron emissive materials comprising of rare-earth hexaborides can be synthesized at reduced temperatures than previously thought
- Suitable gap forming material with good electrical and thermal insulation properties that is chemically compatible with rare-earth hexaborides materials has been identified
- A demountable enclosure with a maximum service temperature of 1400°C, constructed using commercially available products, to meet the ultra-high vacuum and oxidation resistance requirements for the thermionic prototype has been fabricated
- The efficiency of the thermionic device was affected by the low effective heat transfer rates (contact resistance) between the components and by the space charge build up across the 45micron gap
- The combination of the wide scope of the project coupled with a low starting TRL made the project challenging and at times difficult to meet set milestones.