Flicking the Switch

According to the Energy Information Administration, which gathers and analyzes energy data for the U.S. Department of Energy, commercial buildings currently consume 18 percent of the energy in the United States (www.eia.doe.gov). Of this 18 percent, commercial building lighting consumes 23 percent. The general lighting in many existing commercial buildings is either on or off, and there is no ability to adjust light levels for individual preference, space occupancy, the activities taking place in the space or incoming natural light. With energy costs rising, private and public building owners are looking for ways to reduce operating costs. One solution is installing more efficient lighting.

In new buildings, owners are reducing their energy bill by installing more efficient lamps and luminaires, designing the building to take advantage of natural lighting with windows and skylights, and installing lighting control systems. Unfortunately, existing building owners have been limited to replacing or retrofitting existing luminaires and lamps. Existing building architecture often limits daylighting potential, and a wired lighting control system can be very expensive.

However, there are some easy lighting control improvements the electrical contractor can implement that will pay for themselves, save energy and increase customers’ flexibility. ECs should be aware of emerging technologies that make the installation of lighting controls economical for existing buildings.

Easy retrofit control solutions

A lot of energy can be saved in existing commercial buildings if lights are simply turned off when no one is in the space. The deployment of occupancy sensors to accomplish that can be easy and cost-effective. While occupancy sensors have been around for years, they have advanced considerably since their introduction, and there are a number of technologies available for different applications, including passive infrared, ultrasonic and combination technology sensors. Owners can choose the right sensor for the right application.

In addition, sensors can be mounted on walls and ceilings in open office areas and other public spaces as well as simply replacing light switches in private and semiprivate offices, conference rooms and other similar spaces. Commercial-grade occupancy sensors come with a variety of operating modes and features that allow their operation to be easily customized for the space, its use and the occupants’ needs.

Multilevel switching is another easy retrofit strategy, if the existing building luminaires have two ballasts or the space is being retrofitted with new luminaries. Multilevel switching works well with three-lamp luminaires so that with two switches, the light level can be varied at three levels: 33 percent (1 lamp), 67 percent (2 lamps) and 100 percent (3 lamps). This arrangement allows occupants to adjust the light level to their needs and account for incoming daylight. Rewiring individual perimeter offices and conference rooms with a few luminaires can be relatively easy and inexpensive, but large areas may not be as cost-effective.

Integrated control systems

If the customer is looking for a more advanced lighting control system that integrates luminaires and manual and automatic control devices, a number of proprietary systems on the market today will meet the need. These systems are modular and can serve individual spaces or be linked together and tied into an overall lighting control system or building management system. They are also scalable because they typically use a microprocessor-based control unit that is either a stand-alone module that interfaces with a set of standard ballasts or is integrated into a proprietary ballast unit. Furthermore, these systems are programmable and normally use low-voltage control wiring for control devices and sensors, which typically allows the control wiring to be installed without raceway, reducing installation cost and time. >

Emerging wireless controls

As noted above, one of the barriers when retrofitting lighting controls is the wiring. While the use of low-voltage control systems and wiring reduces installation time and cost, it still is expensive and may be challenging to install due to physical obstructions, hazardous materials or historic preservation restrictions. This may change as new ballasts, control devices and sensors using wireless technology enter the market.

The leading wireless control technology currently being integrated into a number of building products is ZigBee, which is a low-power, open-architecture wireless network based on IEEE Standard 802.15.4 and designed specifically for linking devices that perform a monitoring and control function. ZigBee ballasts, control devices and sensors automatically recognize each other and organize themselves into a programmable control network. ZigBee devices have an ultra-low power requirement and can run on batteries for months or years.

With the cost of electricity increasing and the cost of electronics decreasing, customer demand for lighting control retrofits in existing buildings will increase. Be ready to fulfill these demands.   EC

This article is the result of a research project that investigated the emerging IBS market for the electrical contractor that was sponsored by ELECTRI International. The author would like to thank EI for its support.

GLAVINICH is an associate professor in the Department of Civil, Environmental and Architectural Engineering at the University of Kansas. He can be reached at 785.864.3435 or tglavinich@ku.edu.



About the Author

Thomas E. Glavinich

Freelance Writer
Thomas E. Glavinich was an associate professor in the Department of Civil, Environmental and Architectural Engineering at the University of Kansas. His tenure as one of Electrical Contractor's most trusted and reliable source of industry research end...

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