Incorporate
Daylighting Controls in
Architecturally Daylit spaces
An effective
control system is essential for daylighting and electric lighting
for energy savings and occupant satisfaction. For workspaces,
continuous dimming is the least obtrusive. This allows changes
to the electric lighting output to be unnoticeable to occupants.
On/off or multi-step strategies can be distracting and may result
in occupant complaints or tampering with the sensors; these are
best suited for storage areas or other intermittently occupied
areas.
A photosensor
should be assigned to each lighting zone. There are two main types
of daylight controls, “closed loop” and “open loop”.
In a closed-loop system the sensor is located in the controlled
space. This type of system is best for classrooms, open offices,
concourses, lobbies, malls, factories and other large open areas.
In an open loop system the photosensor is located outside the
space(s) it controls, and is not affected by the electric light
contribution. This type of system is appropriate for a series
of small offices or rooms all with the same sky exposure, outdoor
lighting, atria, and other daylighting features.
Cautions
- Requires
time-out and sensitivity adjustments after 100-hour burn-in
of fluorescent lamps, with room furnishings in place and HVAC
systems operating.
- Proper
commissioning is critical for energy savings and occupant satisfaction.
- Sensors
must be periodically calibrated and tested to ensure long-term
energy savings.
