An optical characterization platform for transparent insulation materials in solar energy

Book · Sat Dec 31 04:00:00 EST 1994

OSTI ID:194865

Platzer, W J ^[1]

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1. Fraunhofer-Inst. for Solar Energy Systems, Freiburg (Germany)

The precise optical characterization of transparent insulation materials used in windows, flat-plate collectors or for transparent insulation of buildings, is an important step to design solar collector and daylighting systems with these materials and to estimate energy benefits, peak loads, efficiencies, and different potential risks such as overheating, thermal damage or glare. Physically the aim is clear: Angle-dependent transmittance and reflectance properties for the solar and visible wavelength ranges yield the necessary information for the engineer to enable him to design a good system. However, it is far from trivial to obtain these data with sufficient precision for the rather different materials. The authors have set-up a set of radiation sources and integrating detector spheres which are able to measure directional-hemispherical and hemispherical-hemispherical reflectance and transmittance (hence also absorptance) for the visible and the solar wavelength range. This was possible by applying a PTFE-based coating to the spheres, having a unique spectrally flat response over the whole range, and using non-selective broadband detectors. Careful design tried to optimize integrating sphere geometry. Moreover, spectral measurements between 285--1,100nm are possible with an optical multichannel analyzer utilizing glass fiber optics. The whole experimental set-up will be presented and discussed together with representative results.

• OSTI ID: 194865
• Report Number(s): CONF-9404167--; ISBN 0-8194-1564-2
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
BUILDINGS
EXPERIMENTAL DATA
FLAT PLATE COLLECTORS
OPTICAL PROPERTIES
THERMAL INSULATION
WINDOWS