Page 182 - Solar Power in Building Design The Engineer's Complete Design Resource

152 ENERGY CONSERVATION

In some instances, radio control applications can eliminate trenching and cable
installation, which can offset the entire cost of a central control system. Contrary to
conventional wiring schemes where all wires from fixtures merge into switches and
lighting panels, an intelligent lighting control system, such as the one described here,
makes use of Type 5 cable (a bundle of four-pair twisted shielded wires), which can
interconnect up to 2400 lighting control elements. A central control and monitoring
unit located in an office constantly communicates with a number of remotely located
intelligent control boxes that perform the lighting control measures required by Title
24 and beyond.
Since remote lighting, dimming, and occupancy sensing is actuated by means of
electronically controlled relay contacts, any number of devices such as pumps, out-
door fixtures, and devices with varying voltages can be readily controlled with the
same master station.
In addition to providing intelligent master control, remote station control devices
and intelligent wall-mount switches specifically designed for interfacing with intelli-
gent remote devices provide local lighting and dimming control override. Moreover,
a centralized lighting control system can readily provide required interlocks between
heating, ventilation, and air-conditioning (HVAC) systems by means of intelligent
thermostats. Figure 6.3 depicts a relay lighting control wiring plan.
Even though central intelligent lighting control systems, such as the one described
here, add an initial cost component to the conventional wiring, in the long run the
extended expectancy of lamps, lower maintenance cost, added security, and consider-
able savings resulting from energy conservation undoubtedly justify the added initial
investment.
In fact, the most valuable feature of the system is flexibility of control and ease of
system expansion and reconfiguration. The system is indispensable for applications
such as the Water and Life Museum project discussed in Chapter 5.
The major cost components of a centralized lighting control system consist of the
central- and remote-controlled hardware and dimmable fluorescent T8 ballasts. It is
a well-established fact that centralized lighting control systems pay off in a matter of
a few years and provide a substantial return on investment by the sheer savings on
energy consumption. Needless to say, no measure of security can be achieved with-
out central lighting control. Figure 6.4 depicts a centralized dimming and lighting
control diagram.
The automated centralized lighting control system manufactured by Lighting
Control & Design (LCD), and shown in Figure 6.4, provides typical control compo-
nents used to achieve the energy conservation measures discussed earlier. Note that the
lighting control components and systems presented in this chapter are also available
from Lutron and several other companies.
Some of the major lighting system components available for system design and
integration include centralized microprocessor-based lighting control relays that
incorporate 32 to 64 addressable relay channels, 365-day programmable astronomical
timers, telecommunication modems, mixed voltage output relays (120 or 277 V), man-
ual override for each relay, and a linkup capability of more than 100 links to digital