ABSTRACT
Glazed areas and shading devices have an important role in a building’s energy
consumption. Highly glazed fac¸ades have been increasingly used in new buildings,
allowing access to daylight and an external view. However, the risk of a high cooling
and heating demand in the building must be considered (Hien et al, 2005; Poirazis et al,
The most effective way to reduce the solar load on fenestration is to intercept direct
radiation from the sun before it reaches the glass. The energy performance of buildings
using different shading designs, such as overhangs (Lee and Tavil, 2007), external roller
shades (Tzempelikos and Athienitis, 2007) and venetian blinds (Simmler and Binder,
2008), has been studied. Glazed areas that are fully shaded from the outside reduce
solar heat gain by as much as 80 per cent (ASHRAE, 1997). In all exterior shading
structures, the air must move freely to carry away heat absorbed by the shading and
glazing materials. This is the case with external louvres.
