Thermionic energy conversion

Abstract

The concept of a vacuum thermoelement is attractive as it removes one of the problems in thermoelectric energy conversion, namely heat conduction through a solid. It is shown that efficient thermionic generation in a vacuum device might be possible if improved thermionic emitters become available. It is shown that an emitter with an even smaller work function is needed for a practical thermionic refrigerator. Consideration is also given to solid-state thermionic convertors in which the current flow is ballistic rather than diffusive.