Simulation-based design of an angle-selective and switchable textile shading system

Recent improvements in the manufacture of textiles allow enhanced functionality in architectural applications. In this study, a switchable and angle-selective shading system is developed on the basis of a new textile structure. The geometry of the textile structure is optimized through a simulation-based approach. Textiles are characterized by Bi-directional Scattering Distribution Functions (BSDF), which are calculated by ray-tracing techniques and verified with measurement data from a three-dimensional scanning goniophotometer. The design workflow is constrained by a set of requirements on the optical properties of the shading device. The resulting shading system is evaluated in terms of daylighting provision and glare protection by applying state-of-the-art simulation techniques. For doing that, the optical behaviour of the switchable shading system is discretized in six states. These states are then compared with a conventional, white, glare-protection roller blind. The results of the evaluation indicate that at least one state of the new shading system provides a better daylighting performance than the conventional roller blind, and that at least two states provide better glare protection.