Double-Skin and Mid-Pane Devices
Whereas conventional buildings may have 35 or 40% window surface in the exterior wall, many modern, highly glazed buildings are almost all-glass. That presents many challenges from an energy and comfort point of view: can these buildings respond dynamically to quickly varying outdoor weather conditions and to changing occupants’ needs? Solar shading is part of the solution to that problem. Many of these buildings in Europe have double skin façades, characterized by two glass skins, typically 30 cm apart, but often far more. The cavity between the two skins is ventilated, naturally or mechanically. One of the skins, often the interior, is double glazing. For solar shading, the benefits are truly optimized: they can be placed between the two skins and thereby combine the benefits of both external and internal solar control. In this way the shading system can be used all year long and will not be influenced by wind or other outdoor conditions. The combination of intermediately placed solar shading and ventilation of the cavity is the major advantage of double skin façades.
So-called ‘mid-pane’ shading devices, mostly very thin venetian blinds, may be located in the narrow space between the panes of a double glazed unit.