Spectral radiant heat emitted by honeycomb-type solar collector covers
- Fraunhofer Inst. for Solar Energy Systems, Freiburg (Germany)
A new type of transparent insulation with glass capillaries allows the construction of high temperature flat-plate reaching stagnation temperatures of 260 C and more. In the temperature range above 100 C, the radiant heat is the dominant heat loss mechanism. For the plastic honeycomb materials used up to now, the heat losses were described adequately with a non-spectral ``grey`` model. To describe the radiant heat losses for the new glass capillary collector covers, a spectral analysis is necessary, due to the strong spectral dependence of the absorptance in glass. A new experimental set-up allows the measurements of the spectral radiant heat emitted by large samples, not only integrated over a hemisphere but also with angular resolution. A theoretical model for the calculation of the spectral, angle-dependent total emission of a TI/absorber construction has been developed. The presented results of the calculations for glass capillaries show good agreement with the measurements.
- OSTI ID:
- 194870
- Report Number(s):
- CONF-9404167-; ISBN 0-8194-1564-2; TRN: IM9611%%372
- Resource Relation:
- Conference: SPIE 13: international symposium on optical materials technology for energy efficiency and solar energy conversion, Freiburg (Germany), 18-22 Apr 1994; Other Information: PBD: 1994; Related Information: Is Part Of Optical materials technology for energy efficiency and solar energy conversion XIII; Wittwer, V. [ed.] [Fraunhofer Inst. for Solar Energy Systems, Freiburg (Germany)]; Granqvist, C.G. [ed.] [Uppsala Univ. (Sweden). Dept. of Technology]; Lampert, C. [ed.] [Lawrence Berkeley Lab., Berkeley, CA (United States). Energy and Environment Div.]; PB: 863 p.; Proceedings/SPIE, Volume 2255
- Country of Publication:
- United States
- Language:
- English
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