Wireless Sensor and Actuator Networks for Lighting Energy ...

ecome possible if the system generates more than 60% savings as the blue solid line
reveals in Figure 9-31. Since the system is capable of harvesting daylight and
considering occupancy status simultaneously, it is not unrealistic to expect energy
savings greater than 60% as demonstrated earlier in Chapter 9.4. Like most of the
energy-efficient lighting systems, the projected payback time for retrofitting, however,
stays at the high end of the three- to five-year period acceptable to facility managers for
adopting energy efficient products. The next section provides a detailed discussion on
the potential commercialization bottleneck of the proposed lighting system. An
exemplary analysis of energy savings and payback period for this particular office can
be found in Appendix C.2. The payback period for new installation is about 30% shorter
than for retrofitting without the overhead of dimmable ballasts as the green dashed line
suggests in Figure 9-31. In the meantime, it is important to recognize that in addition to
energy efficiency, the research system also emphasizes on satisfying occupants’ lighting
preferences. This desirable feature and unique advantage could potentially outweigh a
longer but reasonable payback period.
9.5.2 Commercialization Bottleneck
According to Table 9-1, the potential bottleneck for commercializing the
intelligent lighting system will be the dimmable ballasts. Although the prototyping
sensors and actuation modules currently cost more than the dimmable ballasts, the
prices of the components are expected to drop significantly, especially those for the
electronic components. However, the technologies of dimmable ballasts have been
mature and on the market for a while. Even though the notably fewer market demands
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