New Methods for Assessing Spectral, Bi-directional Transmission and Reflection by Complex Fenestration Systems

Advanced fenestration systems are increasingly being used to distribute solar radiation purposefully in buildings. Distribution of visible light and near infrared radiation can be optimized for daylighting and to reduce thermal loads. This can be achieved by fenestration systems that are spectrally and angularly selective. To study these systems, a device that measures the spectral, bi-directional transmission and reflection distribution functions of complex fenestration system components is under development. This device incorporates spectroradiometrically calibrated digital cameras and absorption filters to gather quasi-spectral information. The cameras could also be used to study the distribution of solar radiation in rooms.