Advanced External Shading Device to Maximize Visual and View Performance

Controlling or avoiding direct sun beam shining into the interior is a key criterion for consideration in most architectural daylighting designs. This treatment is mainly intended to attenuate the adverse glare and contrast associated with direct sunlight and to lessen the negative contribution of direct sunlight on the cooling load. Window shades are commonly used in Korea to reduce heat gains in the form of direct beam radiation, particularly in summer. Very often they consist of non-movable structures, such as overhangs, vertical fins or composition of both, forming eggcrate-type systems, and ideally should be designed by incorporating these methods. One of the simplest sunlighting controls is Venetian blind. It plays a role in excluding direct sunlight but reflecting light to rear interior, while still allowing a view to exterior. The blinds also go far toward improving uniformity in illuminance. External shading devices are much more effective than internal shading devices. However, it is not popular because of cost, maintenance, and esthetic reasons. We developed an experimental configuration of external shading device, providing better performance of shading and view. A series of simulations and measurements have verified the differentiated advantages in illumination and building energy consumption by using this system.