APPLICATION OF TECHNOLOGY:

• Sending control signals to electronic fluorescent and high intensity discharge (HID) lamp ballasts over existing wiring

ADVANTAGES:

• Much less expensive than installing control wiring in existing buildings to obtain dimming control
  
• Enables lighting system to respond to available daylight and demand response control
  
• Allows building occupants to dim their local lighting systems
  
• Won’t compromise the electrical distribution system by adding undesirable current harmonics
  
• Favorable signal-to-noise ratio compared to conventional Power Line Carrier (PLC) techniques
  
• Eliminates the possibility of interfering with other upstream building equipment

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.

	Diagram of the Phase Cut Carrier lighting control system which can be implemented using existing wiring.

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.

STATUS: Patent pending. Available for licensing or collaborative research

REFERENCE NUMBER: IB-1871