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Title: Measurements of Conversion Efficiency for a Flat Plate Thermophotovoltaic System Using a Photonic Cavity Test System

The performance of a 1 cm{sup 2} thermophotovoltaic (TPV) module was recently measured in a photonic cavity test system. A conversion efficiency of 11.7% was measured at a radiator temperature of 1076 C and a module temperature of 29.9 C. This experiment achieved the highest direct measurement of efficiency for an integrated TPV system. Efficiency was calculated from the ratio of the peak (load matched) electrical power output and the heat absorption rate. Measurements of these two parameters were made simultaneously to assure the validity of the measured efficiency value. This test was conducted in a photonic cavity which mimicked a typical flat-plate TPV system. The radiator was a large, flat graphite surface. The module was affixed to the top of a copper pedestal for heat absorption measurements. The heat absorption rate was proportional to the axial temperature gradient in the pedestal under steady-state conditions. The test was run in a vacuum to eliminate conductive and convective heat transfer mechanisms. The photonic cavity provides the optimal test environment for TPV efficiency measurements because it incorporates all important physical phenomena found in an integrated TPV system: high radiator emissivity and blackbody spectral shape, photon recycling, Lambertian distribution of incident radiation andmore » complex geometric effects. Furthermore, the large aspect ratio between radiating surface area and radiator/module spacing produces a view factor approaching unity with minimal photon leakage.« less
Authors:
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Publication Date:
OSTI Identifier:
821940
Report Number(s):
LM-00K041
TRN: US0401129
DOE Contract Number:
AC12-00SN39357
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 30 May 2000
Research Org:
Lockheed Martin Corporation, Schenectady, NY 12301 (US)
Sponsoring Org:
US Department of Energy (US)
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ABSORPTION; ASPECT RATIO; COPPER; EFFICIENCY; EMISSIVITY; GRAPHITE; HEAT TRANSFER; PERFORMANCE; PHOTONS; RADIATIONS; RADIATORS; RECYCLING; STEADY-STATE CONDITIONS; SURFACE AREA; TEMPERATURE GRADIENTS