Thermionic converter - Normal and transparent collectors
Abstract
A novel thermionic converter concept is described in which the collector is largely transparent in that the thermal radiation absorbed from the emitter is small, with the greater part transmitted. This can be accomplished by using sapphire as the structure of the collector with a coating of metal tens or hundreds of angstroms thick serving as the electrode surface. Outside of the transparent collector is a reflecting surface (ideally adiabatic) which would operate at or near the same temperature as the emitter. Since thermal radiation is parasitic to the thermionic power conversion process, elimination or reduction of radiation enhances converter efficiency directly. Preliminary analysis suggests that potential efficiencies of near 40 percent may be achievable for the SAVTECs (self-adjusting versatile thermionic converters) with transparent collectors. Such efficiency is attractive in applications ranging from terrestrial solar concentrator heat sources with ambient convection heat rejection to nuclear heat sources with space radiation as the ultimate heat sink.
- Publication:
-
IECEC-90; Proceedings of the 25th Intersociety Energy Conversion Engineering Conference, Volume 2
- Pub Date:
- 1990
- Bibcode:
- 1990iece....2..283F
- Keywords:
-
- Energy Conversion Efficiency;
- Thermal Insulation;
- Thermal Radiation;
- Thermionic Converters;
- Metal Coatings;
- Radiative Heat Transfer;
- Sapphire;
- Thin Films;
- Energy Production and Conversion