Technology Reviews: Shading Systems

Proper building envelope design is the most direct and efficient way to reduce cooling loads, by controling the radiative, convective and conductive heat transfer through the building envelope.

The most effective way to reduce cooling loads is to prevent their generation by controlling the output of the heat sources and the heat transfer through the building envelope. Heat sources can be either external, i.e., direct and diffuse solar radiation along with the associated convective and conductive heat transfer, or internal, i.e., electric lighting, equipment and building occupants. From these sources, only the electric lighting system can be partially controlled by the building designer with respect to output. The strategies to control the generation of cooling loads from the rest of the sources concentrate on the heat transfer modes through the building envelope, focusing on reducing heat transfer from the exterior to the interior and increasing heat transfer from the interior to the exterior.