Highly-Efficient Thermoelectronic Conversion of Heat and Solar Radiation to Electric Power

Thermionic energy conversion has long been a candidate to convert solar radiation and the combustion heat of fossil fuels into electricity at high efficiencies. However, the formation of electron space charges has prevented the widespread use of the principle since its was first suggested in 1915. In this work, a novel mechanism to suppress the effects of the space charge was investigated: the acceleration of electrons in a special configuration of electric and magnetic fields. This work describes the realization of a proof-of-principle experimental generator. Furthermore, based on model calculations and experiments, it gives an assessment of attainable output power densities and efficiencies. Despite substantial efforts in material science and engineering are still required, it is concluded that no fundamental hurdle prevents the realization of highly efficient generators