The primary purpose of a sunshade is to control the amount of direct
sunlight through your building's windows.
Where to Shade
Southern, Eastern, and Western exposures of your building will derive
benefits from solar shading. Southern exposure is the easiest to shade and
provides the greatest energy savings. Occupants, however, will appreciate any
reduction in morning sun glare (Eastern exposure) and afternoon sun glare
(Western exposure). In some climates, these exposures can generate large energy
savings as well. Northern exposures do not require solar shading. The only
reason to shade a Northern exposure is to create uniformity in the building
appearance. Otherwise, virtually no energy benefit can be gained from shading
the North side of a building (again, we are referring to a location in the
Northern Hemisphere).
How to Shade Southern Exposures
Based on the solar altitude and azimuth and orientation of your building,
shading methods will vary. A shelf system is best utilized on Southern
exposures and will allow the best configuration for energy savings. Variations
in the shelf location, projection, and blade spacings will optimize the energy
benefits. The objective is to maximize shading during peak cooling season while
allowing direct sunlight and heat gain during the heating season. In most of
the southern climates, the need for shading throughout the cooling season
generates the greatest energy savings, so we will optimize the shading for this
period (April 15 through September 1). This altitude is 60° in our example.
