advanced building skins 14 | 15 June 2012 - lamp.tugraz.at - Graz ...

Advanced Building Skins
blinds offer sun protection only, without avoiding overheating, as the heat is already inside the
building. Blinds inside the cavity offer a good compromise of functionality, maintenance and design.
An integral louver system has more to offer than merely an aesthetic advantage. Because they are
located inside the cavity, the blinds are protected from weather influences and do not get dirty which
means they are totally maintenance free. More important, the functional glass fulfills all of the
requirements of thermal insulation while allowing a differentiated daylighting to the interior.
Integrated systems exhibit a slightly higher amount of total solar energy transmission than systems
mounted on the exterior. Blinds mounted on the interior have the worst functionality in this
comparison. Practice proves them to be extremely prone to becoming dirty as well as needing
intensive maintenance. They are also hardly able to keep the summer heat out of the interior rooms.
They only afford a certain amount of glare control.
Integrated sun control systems are therefore a good compromise for a variety of different requirements.
These systems can be either fixed or movable. Even fixed louver systems, without any moving
components, allow for effective sun control and a self-regulatory function. Compared to conventional
glass with a homogeneous sun control coating the amount of incoming sunlight and with it the total
solar energy depends strongly on the position of the sun (Figure 11).
Figure 11: The selective light and solar energy transmittance of fixed integral louver systems depend on the sun
angle.
The cross-section and surface of the slat as well as the spacing and the orientation of the single slats
are decisive for perfect functioning of a sun control system. But the function also depends on the
current radiation and weather conditions. The system should be designed in such a way as to largely
suppress direct sunlight in summer allowing only diffused daylight to enter the room.
Figure 12: Integral sun control system at the façade of the Landesdenkmalamt Baden-Württemberg, Esslingen.
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Without sun control
With sun control