BDCS - Brise Soleil

A typical wooden brise soleil, shading overly transparent exteriors

Brise soleil, (from French, "sun breaker"), in architecture refers to a variety of permanent sun-shading techniques, ranging from the simple patterned concrete walls popularized by Le Corbusier to the elaborate wing-like mechanism devised by Santiago Calatrava for the Milwaukee Art Museum or the mechanical, pattern-creating devices of the Institut du Monde Arabe by Jean Nouvel.

Calatrava's wing-like mechanism as seen from inside the Milwaukee Art Museum

In the typical form, a horizontal projection extends from the sunside facade of a building. This is most commonly used to prevent facades with a large amount of glass from overheating during the summer. Often louvers are incorporated into the shade to prevent the high-angle summer sun falling on the facade, but also to allow the low-angle winter sun to provide some passive solar heating.

Originally, brise soleils were constructed out of concrete, per Le Corbusier's tenets established in his Towards a New Architecture, widely considered now a manifesto for all things modern architecture

On the Arab World Institute, where Nouvel pioneered his brise soleil innovation in his Institut du Monde Arabe: one sees a glass-clad storefront where a metallic screen unfolds with moving geometric motifs. The motifs are actually 240 motor-controlled apertures, which open and close every hour. They act as brise soleil to control the light entering the building. The mechanism creates interior spaces with filtered light — an effect often used in Islamic architecture with its climate-oriented strategies. This building catapulted Nouvel to fame and is one of the cultural reference points of Paris.

Nouvel's metallic screens with circular apertures