Seebeck Effect Generators for Orbit-to-Ground Power Supply

Abstract

In this paper, we examine two types of Seebeck effect generators in three different configurations when exposed to thermal gradients representative of the thermal load which would be experienced by such a device when placed in Earth, Lunar, or Solar orbit under full Sun exposure in a configuration representative of a theoretical satellite with the purpose of gathering large amounts of energy from the Sun and transmitting that energy back to Earth through the use of visible wavelength lasers. We compare the voltage output and electrical conductance of 65x65mm Bismuth-Telluride (BiTe) and Calcium-Manganese Oxide (CMO) Seebeck effect generators individually and in a serial hybrid configuration which positions the generators in such a way as to take advantage of their different optimal temperature ranges. We also compare the power transfer effectiveness of a polycrystalline silicon photovoltaic cell when exposed to three lasers of different visible wavelengths including a 405nm violet laser, a 532nm green laser, and a 650nm red laser. By experimentally determining the power transfer through each component, we derive a theoretical effectiveness of a system designed to collect and transmit energy from orbit to the Earth, and the effectiveness of each of the major components in that system. Our analysis of the Seebeck effect generators shows that the serial hybrid configuration outperforms the individual generators under all temperature gradients examined, with the highest average Seebeck coefficient and maximum power transfer of the three and achieving a maximum power transfer rate of 9.5W at a temperature gradient of 200℃. The 532nm laser was found to have the best performance of all three lasers examined, having a maximum observed power transfer of 37.0%, reduced to a maximum theoretical power transfer through the atmosphere of the Earth of 32.9%.