Converters of the Thermal Component of Concentrated Solar Radiation Based on Granular Silicon

Abstract

This study provides the results of researching electrophysical properties of granular silicon powder without any agglomeration of a powder placed in a dielectric, formative housing with metal contacts. The particles of silicon powder of the working body, made on this basis as a thermal energy converter, are mechanically pressed against each other with a certain force. The heating of this body results in abnormally high open-circuit voltage (Uoc) and short-circuit current (Isc). The Seebeck coefficient of this material at temperatures from 300 to 350 K is 10 times greater than that of single-crystal silicon and equal to ~500 μV/K and the thermal conductivity is ~16 W/(m K), which is, respectively, 9 times lower than that of single-crystal silicon. Short-circuit current Isc depends on the magnitude of the external pressure and the temperature gradient along the length of the specimen’s working body. Granular silicon thermal energy converters can be used in several extreme conditions, including exposure to high radiation levels, unlike single- or polycrystal silicon semiconductor devices. Various designs and characteristics of heat and pressure converters are presented, which use medium-intensity concentrated solar radiation as a source of thermal energy.