7.2.1 Automatically Controlled Window Shades

Some advanced buildings include either interior or exterior shading systems that include automatic controls to optimize the shade position for energy savings. In some cases, this may be as simple as a time based control system that operates the shades based upon time of day. More sophisticated systems may include sensors designed to detect solar gains on the fenestration, and determine the optimum shade position.

Most simulation programs include a variety of commands to facilitate modeling the various scenarios that will be found in buildings. In the case of the simple time of day based control system, a straightforward hourly/daily/monthly schedule command can be utilized that will adjust the solar gain through the fenestration using a multiplier that is applied to the hourly solar gain.

For the more sophisticated case, a solar gain or glare threshold should be input that will result in the shades being closed. In some software, this may include hourly pairs of values that describe the solar gain threshold and corresponding solar gain multiplier resulting from the shade.