TY - JOUR T1 - Light-scattering properties of a Venetian blind slat used for daylighting applications JF - Solar Energy Y1 - 2010/12// SP - 2103 EP - 2111 A1 - Annica M. Nilsson A1 - Jacob C. Jonsson KW - ABg-model KW - BSDF KW - Raytracing KW - Venetian blinds AB - 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. VL - 84 IS - 12 JO - Solar Energy DO - 10.1016/j.solener.2010.09.005 ER - TY - JOUR T1 - Optical characterization of fritted glass for architectural applications JF - Optical Materials Y1 - 2009/ SP - 949 EP - 958 A1 - Jacob C. Jonsson A1 - Michael D. Rubin A1 - Annica M. Nilsson A1 - Andreas Jonsson A1 - Arne Roos KW - BRDF KW - BTDF KW - Fritted glass KW - Integrating sphere KW - light scattering AB - 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. VL - 31 IS - 6 JO - Optical Materials DO - 10.1016/j.optmat.2008.10.050 ER -