Irregular light scattering properties of innovative fenestration for comfortable and energy-efficient buildings

The irregular reflection and transmission properties of innovative fenestration components allow to redirect, and to selectively admit or block solar irradiation based on its incident direction. Compared to e.g. systems that implement adaptivity to external conditions by mechanical transformations, such tailored light scattering properties promise to reduce the complexity of installation, operation and maintenance as well as the impact on outward view and the aesthetical appearance of buildings. Examples of such innovative fenestration techniques, e.g. light redirecting films and Venetian blinds featuring irregular reflection properties, are presented with their gonio-photometrically measured light scattering properties. Techniques to model such innovative, optically complex fenestration in building simulation software to support product development and planning are presented. The effects on daylight availability, glare and solar gains are demonstrated for exemplary cases. Preliminary results indicate the potential of such innovative fenestration technology to control and modulate rather than to block solar irradiation with minimal interventions in the design of buildings aiming at high performance in terms of comfort and energy efficiency.