Determination and Application of Bidirectional Solar-Optical Properties of Fenestration Systems

Accurate determination of the luminous and thermal performance of fenestration systems that incorporate optically complex components requires detailed knowledge of their radiant behavior. We describe a large scanning radiometer used to measure the bidirectional transmittance and reflectance of fenestration systems and components. We present examples of measured data obtained for simple non-specular samples. We describe a method of obtaining the overall properties of fenestration systems by calculation from scanning radiometer measurements of fenestration components. Finally, we describe the application of bidirectional solar-optical properties of fenestration systems to determine their luminous and thermal performance with respect to building energy consumption and occupants comfort. We also discuss the advantages and limitations of the method, which appears to be promising.