Wireless Sensor and Actuator Networks for Lighting Energy ...

light output from the daylight simulating structure reached the maximum level. Notice
that each stair in Figure 9-19 indicates a new energy usage level after a set of new
iterations of lighting optimization was triggered and revised light settings were
delivered. Remember that the lighting optimization algorithm was not necessarily
triggered every time the simulated daylight changed, but only when the task illuminance
on any of the present occupant’s desk diverged from specified preference by 5%.
Figure 9-19 Percentage of energy consumption in the first case.
Seven-occupant case with simple daylight changing sequence
This test considered a more compactly occupied office where seven occupants
were present with a wide range of lighting preferences as shown in Figure 9-20. Figure
9-21 illustrates the change sequence of the simulated daylight. The simulated daylight
was turned on to the dimmest level four minutes after the test started and was gradually
brightened approximately every two minutes to the maximum. The simulated daylight
was then dimmed to 50% for two minutes, turned back up to the maximal level, and
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