Performance of a daylight-redirecting glass-shading system

• We tested a performance of a daylight-redirecting glass-shading system.
• The measurements were carried at the demonstration building.
• The analysis and the performance assessment were carried out by program Radiance.
• We found out that redirecting daylight can improve visual comfort in the room.

This paper evaluates the daylighting performance of a prototype external dynamic shading and daylight-redirecting system, and the main focus is on the performance simulation. The demonstration project was carried out on a building with an open-plan office. Part of the original façade was replaced with the prototype façade. This layout allowed the use of the same orientation and surroundings for both façades. The working plane illuminance was measured over several months and the measurements were accompanied with annual daylight simulations. The prototype system improved the daylighting conditions compared to the original system. The visual comfort was evaluated by glare analysis and the redirected daylight did not cause an additional discomfort glare. The higher utilization of daylight can save 20% of the lighting energy. The thermal insulation of the fenestration was maintained, with slightly increased solar gains, but without producing an excessive overheating.