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ABSTRACT:
Francis
Rubinstein of Berkeley Lab and Peter Pettler of Vistron, Corp.have
made it possible to reliably send control signals from an
electrical junction box to fluorescent and high intensity
discharge (HID) lamps over existing wiring. The Phase Cut
Carrier (PCC) system works without compromising the performance
of the electrical wiring distribution system and has several
advantages over Power Line Carrier (PLC), the conventional
technique used to communicate with building loads over in-place
wiring.
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Diagram of the Phase Cut Carrier lighting control
system which can be implemented using existing wiring. |
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The
Berkeley Lab dimmable lighting control system not only provides
increased lighting comfort and control to users, but allows
building managers to reduce operating costs by implementing
advanced lighting control strategies, such as daylighting
and demand response control. Daylighting uses photosensors
to measure daylight and automatically raises or lowers electric
light levels in response. This results in significant cost
savings since the daylighting potential is greatest when electricity
prices are highest. Demand response control allows building
managers to reduce lighting in entire facilities during periods
when they have been notified that electricity shortages are
likely or imminent. Energy regulators in states that have
an insufficient electrical capacity are re-structuring electricity
billing to encourage the use of demand response control beyond
the current rate schedule.
Retrofitting existing buildings with dimmable ballasts to
implement these strategies has been prohibitively expensive
in the past partly because installing additional control wiring
between ceiling-mounted junction boxes and overhead lighting
systems is very expensive and error-prone. The PCC technology
simplifies the installation and reduces its cost.
In addition to replacing the existing ballasts with commercially-available
dimming ballasts, the Berkeley Lab system requires adding
an encoder to each switch zone and installing decoders on
each ballast to be controlled. Eventually, ballast manufacturers
may embed the decoder directly into their dimmable ballasts
making the retrofit even easier and less expensive. Berkeley
Lab researchers estimate that the system would cost about
a dollar per square foot to install in existing buildings
(labor and parts included), and could result in energy savings
of 20 cents per square foot per year.
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