Status of TPV-energy conversion

R&D effort in TPV-Energy Conversion, which just has passed the 5-year milestone, was concentrated on the two major components, the photovoltaic, p-n junction conversion device, and the radiation heat source. Three types of germanium photovoltaic cells were under intense study and their performance characteristics are analyzed and results presented. The performance characteristics of a high radiation intensity Si-photovoltaic cell was also analyzed, using a SiC and various types of rare earth oxide radiators. Results are compared with the germanium cell performance and conclusions are drawn for future promising effort. Radiation heat source development is now channeled into studies on highly efficient, spectrally selective radiators of the rare earth oxide type. Initial results of these studies have recently become available and indicate a possible breakthrough in the effort to increase the spectral efficiency of the TPV-system. Test results on a small (100 Watt) model TPV-Generator are presented to demonstrate state of the art hardware development. Future effort will emphasize the optimization of the rare earth emitter materials and the appropriate matching with the photovoltaic cell characteristics. (No major system hardware development is contemplated for the next three years.)