Germanium-silicon, lead telluride, and bismuth telluride alloy solar thermoelectric generators for venus and mercury probes

The design, theory, and fabrication of Bi₂Te₃ alloy solar thermoelectric flat plate generators for near-Earth orbit missions has been previously described. [1] This present paper considers the feasibility of extending its application to auxiliary power systems for exploratory missions towards the Sun for the incident solar radiation fluxes from 130 to 1000 W/ft². The principal potential advantages of flat plate solar generator technology for these high solar fluxes are increased power-per-unit area, increased power-per-unit weight, increased power-per-unit cost and increased radiation resistance. Design equations and comoputational techniques are discussed which allow approximate solution for the generator output power as a function of distance from launch. Commercially available Bi₂Te₃ alloy, PbTe, and SiGe alloy materials are considered separately though combined systems may offer a greater flexibility of power design for any particular mission.

With state-of-the-art thermoelectric materials and emissive coating technology and for the worst case of equal absorber and radiator plate areas, the principal results of these calculations are as follows: For near Mercury and Venus orbits, PbTe has a higher W/ft² (21 W/ft²) than GeSi or Bi₂Te₃ alloy; but GeSi alloy has a higher W/lb of thermoelectric material (1000 W/lb).