Page 199 - Solar Power in Building Design The Engineer's Complete Design Resource

OUTDOOR LIGHTING AND SIGNS 169

The power from the solar panels is distributed in the following three ways:
(1) 2.2 kW is dedicated to the lighting in the office; (2) 11.5 kW powers the lights
in the warehouse; and (3) 11.5 kW is not needed by the lighting system, so it is
inverted to alternating current and used elsewhere in the building or sold back to
the utility.
The entire system consists of 35 Nextek model NPS1000 smart power routers. As
mentioned previously, these devices take all the power from the solar panels and send
it directly to the lighting without significant losses. Additional power, when needed at
night or on cloudy days, is taken from the grid. Figure 6.13 depicts an interior light-
ing cluster control wiring plan.
In this project a number of NPS1000 lighting control power modules provide elec-
tric energy to 198 four-foot fluorescent fixtures that use two T8 energy-efficient lamps,
illuminating the entire warehouse. Each of the fixtures is equipped with a high-
efficiency dc ballast. Fixtures are controlled by a combination of manual switches,
daylight sensors, and occupancy sensors located in various zones. Lamp fixtures with
more than two lamps are controlled in a manner so that they can be dimmed by

CLUSTERING ELECTRICAL LOADS
AROUND THE POWER MODULE

220 VAC line

Example of unit clustering with the Nextek NPS1000. Figure 6.13 Interior
Note that one circuit breaker from the power panel lighting cluster control
will support five Nextek units for up to
wiring. Photo courtesy of Nextek
50 two-lamp fixtures.
Power Systems.