Wireless Lighting Control - EPM Archives

The last barrier preventing the widespread use of effective lighting controls is about to be broken with the advent of wireless control. Beta testing sites are now generating feedback that designers will use to provide simple and affordable control of lighting systems within the next year. Lights left blazing on at night in buildings in every city in the nation demonstrate the need for a more widely applied control technology. Homeland security provides a rationale for leaving some lights burning. But more often lights are left full on because of our attitudes toward energy.

Existing lighting control technologies may fail to provide expected energy savings. Facilities often find themselves with sophisticated lighting control systems that the occupants who work in the spaces find too difficult to manage. These controls are often go unused or are bypassed. Sometimes, controls are installed with little or no attention paid to proper adjustment or monitoring for proper operation. Some lighting systems are turned on and off from circuit breakers-a practice that can lead to the failure of this circuit protection device to trip on an overload. Switches may be hard to find in some spaces where moves and rearrangements have made them inaccessible. Wireless controls promise to reduce or eliminate these problems.

Wireless lighting controls also promise to greatly reduce installation costs for new systems and allow cost-effective retrofits in existing buildings. However, the bigger promise is for individual control of lighting associated with a worker's space.

Research at the Lighting Research Center (LRC) shows that when individual control is provided, building occupants are more responsible about controlling their lighting. At one test site, occupants used 40% less lighting energy when they were given individual control.

In addition to the higher potential for energy savings, a wireless system will have significant potential for demand-reduction strategies in response to automated signals from a utility. The savings from such demand-response controls will play a more important role when real-time-pricing (RTP) rates become more common in the future.

There are wireless lighting switches on the market today, but they were developed for the residential market to control a particular relay plugged into a wall receptacle and operate table lamps. These switches do not address the more critical requirements of commercial buildings where the lighting is not normally plugged into wall receptacles and where much more flexibility is needed.

Researchers at the University of California (UC), Berkeley's Center for the Built Environment (CBE) received a grant in 2004 from the California Energy Commission (CEC) to develop a flexible, low-cost lighting control system that will provide commercial building owners with significant energy savings and more satisfied tenants. Unlike lighting control systems now available, CBE's proposed system promises to be compatible with a wide variety of existing light luminaires, lamps, and ballasts. In pilot installations, CBE has installed light controllers in a matter of minutes.

According to CBE research specialist Charles Huizenga, the cost of installing today's wired switches is approximately $150 to $200 per switch. “Improvements in wireless technology will make our system cost effective for many applications. We estimate that within a few years, the installed cost of our wireless devices could be as low as $25 per device,” he said.

Other research efforts include a Wireless Lighting Control Initiative, in which the U.S. Department of Energy (DOE) Lawrence Berkeley National Laboratory is working to create an advanced system that will enable organizations to implement wireless lighting control strategies without incurring high wiring costs.

Francis Rubinstein, staff scientist for Department of Energy's Lawrence Berkeley National Laboratory says “Advanced lighting control systems can dramatically reduce the amount of energy used for lighting while increasing occupant comfort.” LBNL has teamed with SVA Lighting, USA, and Dust Networks, which provide enterprise-class low-power wireless mesh networking systems.

Beyond the research laboratories, there are commercial systems that promise to be available within months. One major company-Philips Lighting Electronics-is planning to introduce a comprehensive wireless lighting control system in early 2006 that it believes will be competitive in both new and retrofit markets.

The system, announced and demonstrated to select customers at Lightfair International 2005 in New York, will be marketed through Philips' Advance division. The system features ballasts with the wireless capability built in and software to guide users through a simple commissioning process.”

The new ballasts, with built-in wireless receivers, replace the existing ballast in each luminaire. This wireless system is based on a networking concept called mesh networks. This type of network features wireless nodes that are linked together to form a self-organizing network, an important feature for providing a cost-effective solution.

The Philips Lighting Electronics system, based on the open ZigBee protocol, features a transmitter that plugs into a USB port that enables occupants and facilities managers to communicate to individual or groups of light luminaires from their personal computer (PC), laptop, or PDA. ZigBee uses an IEEE standard, making it easy for devices to communicate and operate with each other. Occupants can control light levels in their workspaces via a their desktop PC, laptop, or PDA. Facility managers can access the system to control lights and sensors throughout their buildings using a local or remote PC through a customizable web interface. The system sends and receives status as well as controls luminaires and strategically placed occupancy and daylight sensors. Each device-ballast, wall switch, occupancy sensor, or daylight sensor can communicate independently and can be configured in any way required.

Building managers need controls that are flexible and scalable. As the requirements of a building change, so do the system requirements. The system allows users to make changes and modifications to their building systems without having to rewire any system devices.

The features include:

Ballasts with an integrated built-in wireless control interface
Easy installation, eliminating dimming panels and control wires
Full addressability with up to 65,000 node capabilities
Wireless interface based on the widely accepted ZigBee Open Protocol
Ability to communicate with other ballasts and controls in a mesh configuration, ensuring that there is no point of failure within the system

Building lighting systems need to be able to communicate with other building systems to provide increased levels of personal comfort, safety, and security. Wireless connections will make it easy for devices to communicate with other building systems such as HVAC equipment and controls and the ZigBee open protocol will foster the required interoperability.

Wireless lighting control promises to deliver the control needed to complete the energy savings formula and to provide occupant comfort satisfaction.