Wireless Sensor and Actuator Networks for Lighting Energy ...

Furthermore, the structure allows the luminaire to tilt and thus simulate different
incident angles.
Figure 9-15 Daylight simulating structure.
The structure was mounted on top of the file cabinet that separates the work area
and the group meeting area in the office; it faced the work area to mimic a window with
daylight penetrating through it. The overall height of this daylight source from the floor
to the center of the troffer was 6.8'.
The light spectrum generated from the daylight simulating structure is close to
natural daylight, the intensity, however, is much weaker. The intensity of the simulated
daylight attenuates quickly with distance. When illuminated by the simulated daylight
alone, the horizontal illuminance on the closest desktop used in this test, approximately
ten feet away from the structure, is about 100 lux, and that on the farthest desktop is less
than 10 lux. In other words, the simulated daylight can at most contribute to roughly
one-third of the lighting required by the occupants. Although not as strong as true
daylight, the simulated daylight is good for testing the system performance under the
163