6. Remarks on Shading Systems

Over the last century, the proportion of the office buildings’ envelope that is transparent has increased significantly. Due to the low thermal insulation property of glass, in comparison to mass opaque building materials, the larger the transparent fraction of the building’s envelope, the more important is the control of solar energy inflow, in order to keep thermal and visual conditions indoors in acceptable levels. Transparent facades need an additional control system, one that helps avoid solar radiation during the overheated period, allows enough thermal loads during the underheated period and ensures comfortable visual conditions during operating hours. Due to the fact that passive design is most of the times not totally efficient for the control of solar and thermal gains, additional active systems are used to balance the interior thermal and visual comfort conditions. As a result, today’s buildings are dominated by technical systems for heating, cooling, ventilation and artificial lighting often resulting in high conventional energy consumption.