The Myths and Realities of Thermophotovoltaic Energy Conversion
- Paper number
IAC-06-C3.2.06
- Author
Mr. Edward Brown, Lockheed Martin, United States
- Year
2006
- Abstract
Abstract. Over the past ten years, advances in thermophotovoltaics (TPV) energy conversion have increased measured conversion efficiencies from about 5Key aspects in the achievement of these performance milestones have been the ability to test integrated hardware in prototypic photonic environments and accurately model experimental results. In this paper, we present results of efficiency measurements for small (1-4 cm2) modules carried out in a photonic cavity test are as well as qualification comparisons for the computer models used to predict performance parameters. Results of a larger (50 watt) array are included to quantify the extrapolation from small module tests to full-scaled systems. In some applications, it may be advantageous to operate TPV modules at elevated temperatures which tends to reduce conversion efficiency. Measurements have been carried out on five modules to determine the magnitude of the efficiency sensitivity to module temperature. Results show that efficiency decreases by about one fourth when the module temperature increases from 30 to 75°C. The performance trends appear very linear and, in all cases, conversion efficiencies remain above 15To determine the longevity of the TPV modules operating at elevated temperatures, modules have been subjected to long “soaks” at elevated temperatures under vacuum conditions. In the extreme case, a module was held at 68°C for more than 3500 hours. Periodic evaluation showed no measurable degradation.
- Abstract document