TPV efficiency predictions and measurements for a closed cavity geometry

Technical Report · Thu May 01 04:00:00 EDT 1997

DOI:https://doi.org/10.2172/325754· OSTI ID:325754

Gethers, C K; Ballinger, C T; Postlethwait, M A; DePoy, D M; Baldasaro, P F ^[1]

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1. Lockheed Martin Corp., Schenectady, NY (United States)

A thermophotovoltaic (TPV) efficiency measurement, within a closed cavity, is an integrated test which incorporates four fundamental parameters of TPV direct energy conversion. These are: (1) the TPV devices, (2) spectral control, (3) a radiation/photon source, and (4) closed cavity geometry affects. The overall efficiency of the TPV device is controlled by the TPV cell performance, the spectral control characteristics, the radiator temperature and the geometric arrangement. Controlled efficiency measurements and predictions provide valuable feedback on all four. This paper describes and compares two computer codes developed to model 16, 1 cm{sup 2} TPV cells (in a 4x4 configuration) in a cavity geometry. The first code subdivides the infrared spectrum into several bands and then numerically integrates over the spectrum to provide absorbed heat flux and cell performance predictions (assuming infinite parallel plates). The second utilizes a Monte Carlo Ray-Tracing code that tracks photons, from birth at the radiation source, until they either escape or are absorbed. Absorption depends upon energy dependent reflection probabilities assigned to every geometrical surface within the cavity. The model also has the capability of tallying above and below bandgap absorptions (as a function of location) and can support various radiator temperature profiles. The arrays are fabricated using 0.55 eV InGaAs cells with Si/SiO interference filters for spectral control and at steady state conditions, array efficiency was calculated as the ratio of the load matched power to its absorbed heat flux. Preliminary experimental results are also compared with predictions.

• Research Organization: Knolls Atomic Power Lab., Schenectady, NY (United States)
• Sponsoring Organization: USDOE Assistant Secretary for Nuclear Energy, Washington, DC (United States)
• DOE Contract Number: AC12-76SN00052
• OSTI ID: 325754
• Report Number(s): KAPL-P--000177; K--97064; CONF-9705119--; ON: DE99001955
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
99 GENERAL AND MISCELLANEOUS
COMPARATIVE EVALUATIONS
COMPUTER CODES
EXPERIMENTAL DATA
INFRARED RADIATION
PERFORMANCE
QUANTUM EFFICIENCY
RADIATION SOURCES
THEORETICAL DATA
THERMOPHOTOVOLTAIC CONVERTERS