Transparency and the Performance of Building Skins

摘要

Glass manipulates the observer's perception of space and can produce the visual effect of dematerialising enclosing walls and facades. Since Mies van der Rohe's unbuilt glass tower [Hochhaus aus Glas 1920-21], the dream of curved and seamless glass walls wrapping large buildings has been present, sometimes in combination with, but more often opposed to, that other Modernist dream of transparency - a spatial continuity between interior and exterior. Transparency, once a spatial ideal, has been subsumed into the more literal transparency of glass. Transparency is neither a simple nor a static condition, and even the orthogonal planar curtain wall will produce a variation of effects between compete reflection and full transparency, dependent on the position of the viewer and the weather. It is the efforts to control the less desirable effects of glass curtain walls, particularly heat gains and losses, glare and reflection, noise and sound, that have provided the major technological imperative for recent design development.