Prototype Design of a Small Scale Thermionic Energy Generator for Waste Heat Recovery in Hybrid Electric Vehicle

Sustainable energy solution for hybrid electric vehicles is an important area of research. Mobility and its ease is therefore being an essential component of development. Automotive technology is an area where methods are explored in recent times to provide sustainable solution for reduction of fuel consumption and carbon emissions by switching to hybrid technology and electric vehicles where regeneration of energy plays an important role. At present the research is focused on achieving methods of solid state conversion of heat into electricity but it is limited to thermoelectric methods which has lower conversion efficiency. A comparative analysis of the direct energy convertors shows that thermionic energy conversion stands better with a higher conversion efficiency. Very close and non-contact type of electrode spacing having electrical insulation provided with vacuum or inert gas environment is the basic requirement while designing any thermionic energy generator. Identifying these key research challenges, this article discusses the design of a prototype small scale thermionic generator. The paper hence explores a platform for conducting experimental research on solid state thermionic conversion, space charge limitation and thermionic emission using low work function materials.