Measurement of bidirectional optical properties of complex shading devices
A new method of predicting the solar heat gain through complex fenestration systems involving nonspecular layers such as shades or blinds has been examined in a project jointly sponsored by ASHRAE and DOE. In this method, a scanning radiometer is used to measure the bidirectional radiative transmittance and reflectance of each layer of a fenestration system. The properties of systems containing these layers are then built up computationally from the measured layer properties using a transmission/multiple-reflection calculation. The calculation produces the total directional-hemispherical transmittance of the fenestration system and the layer-by-layer absorptances. These properties are in turn combined with layer-specific measurements of the inward-flowing fractions of absorbed solar energy to produce the overall solar heat gain coefficient. This paper describes the method of measuring the spatially averaged bidirectional optical properties using an automated, large-sample gonioradiometer/photometer, termed a ``Scanning Radiometer.`` Property measurements are presented for one of the most optically complex systems in common use, a venetian blind. These measurements will form the basis for optical system calculations used to test the method of determining performance.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States); American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., Atlanta, GA (United States)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 70819
- Report Number(s):
- LBL-36243; CONF-950104-9; ON: DE95012250; CNN: A bg 87-127
- Resource Relation:
- Conference: American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) winter meeting and exhibition, Chicago, IL (United States), 28 Jan - 1 Feb 1995; Other Information: PBD: Jan 1995
- Country of Publication:
- United States
- Language:
- English
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A new method for predicting the solar heat gain of complex fenestration systems
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