@article {58219, title = {Light-scattering properties of a Venetian blind slat used for daylighting applications}, journal = {Solar Energy}, volume = {84}, year = {2010}, month = {12/2010}, pages = {2103 - 2111}, abstract = {

The low cost, simplicity, and aesthetic appearance of external and internal shading devices, make them commonly used for daylighting and glare-control applications. Shading devices, such as Venetian blinds, screens, and roller shades, generally exhibit light scattering and/or light redirecting properties. This requires the bi-directional scattering distribution function (BSDF) of the material to be known in order to accurately predict the daylight distribution and energy flow through the fenestration system. Acquiring the complete BSDF is not a straightforward task, and to complete the process it is often required that a model is used to complement the measured data. In this project, a Venetian blind slat with a white top surface and a brushed aluminum bottom surface was optically characterized. A goniophotometer and an integrating sphere spectrophotometer were used to determine the angle resolved and hemispherical reflectance of the sample, respectively. The acquired data were fitted to a scattering model providing one Lambertian and one angle dependent description of the surface properties. These were used in combination with raytracing to obtain the complete BSDFs of the Venetian blind system.

}, keywords = {ABg-model, BSDF, Raytracing, Venetian blinds}, issn = {0038092X}, doi = {10.1016/j.solener.2010.09.005}, author = {Annica M. Nilsson and Jacob C. Jonsson} } @article {58221, title = {Optical characterization of fritted glass for architectural applications}, journal = {Optical Materials}, volume = {31}, year = {2009}, month = {4/2009}, pages = {949 - 958}, abstract = {

Fritted glass is commonly used as a light diffusing element in modern buildings. Traditionally it has been used for aesthetic purposes but it can also be used for energy savings by incorporating it in novel daylighting systems? To answer such questions the light scattering properties must be properly characterized.

This paper contains measurements of different varieties of fritted glass, ranging from the simplest direct-hemispherical measurements to angle-resolved goniometer measurements. Modeling the light scattering to obtain the full bidirectional scattering distribution function (BSDF) extends the measured data, making it useful in simulation programs such as Window 6 and Radiance. Surface profilometry results and SEM micrographs are included to demonstrate the surface properties of the samples studied.

}, keywords = {BRDF, BTDF, Fritted glass, Integrating sphere, light scattering}, issn = {09253467}, doi = {10.1016/j.optmat.2008.10.050}, author = {Jacob C. Jonsson and Michael D. Rubin and Annica M. Nilsson and Andreas Jonsson and Arne Roos} }