Wireless Sensor and Actuator Networks for Lighting Energy ...

9.4 Daylight Response
The second phase of this implementation integrates the system with the wireless
photosensors developed in Chapter 7.2 and the lighting optimization algorithm
developed in Chapter 6.3 for harvesting daylight. This phase serves as the verification
of the research lighting system performance operating under the presence of extraneous
and uncontrollable light sources. The capacity to respond to daylight is a critical feature
for the developed system as daylight harvesting is one of the most energy efficient
lighting management strategies.
9.4.1 Experiment Setup
An important simplification of the occupants’ lighting preferences was made for
this assessment. Although an ideal lighting condition includes sufficient task
illuminance as well as desirable surrounding lighting, occupants’ lighting preferences
were strictly confined to the illuminances on their desktops for simplicity. In other
words, the desktop illuminance specified by an occupant in the first phase of the
assessment was considered as his/her lighting preference. Incorporating the lessons
learned from Chapter 8.3 – that sensor readings don’t always perfectly match the task
illuminances due to the locations of sensors – occupants’ lighting preferences were
defined by the sensor readings instead of illuminances directly read off of a light meter
placed at the center of the working areas.
Since the occupants mostly worked on their own desks instead of in the group
meeting area, only the part of the office with the workstations was implemented with
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