A 100 Watt Radioisotope Energy System Using Current Generation Thermophotovoltaic Technology that Produces 13 Watts/Kg
- Paper ID
5459
- author
- company
Lockheed Martin
- country
United States
- year
2006
- abstract
Abstract. A critical issue in Radioisotope-Thermophotovoltaic (RTPV) space power systems is the size of the heat rejection radiator which is strongly dependent on the temperature at which heat is rejected to the ambient environment. Many of the RTPV system studies performed over the past ~10 years were based on the mistaken assumption that the TPV cells must operate at or near room temperature. Consequently, the heat rejection radiators in those studies were large and unattractive for many potential missions. Recent studies indicate that a 100 W output RTPV system using 2 GPHS units and TPV cells operating at 50 °C has the potential of achieving 16 W/kg specific power with a 1 m2 heat rejection radiator. Alternatively, an RTPV system using 3 GPHS units and TPV cells operating at 140 °C would have slightly reduced specific power (~13 W/kg) but would reduce the size of the heat rejection radiator by about a factor of 2X. Unfortunately, Sb2Se3 (the high refractive index material used in current TPV filters) exhibits an abrupt amorphous-to-polycrystalline phase transition at a temperature of ~140 °C. Initial time at temperature testing has indicated that long term operation of current TPV filters containing Sb2Se3 must be limited to temperatures less than 100 °C. GaTe and Sb2S3 have been identified as potential high index of refraction filter materials with significantly higher temperature capability than Sb2Se3. TPV filters using GaTe and Sb2S3 have been designed and fabricated and initial results indicate that they are capable of operation at temperatures of 150 °C or greater. Measured performance (spectral and time at temperature) of TPV filters containing Sb2Se3, GaTe, and Sb2S3 will be presented along with the impact that these filters would have on RTPV system performance.