Top Tips for Daylighting Control
Staff -- Consulting-Specifying Engineer, 3/1/2005
The term "daylighting" often appears in the pages of this magazine, but perhaps without a clearly defined notion of the engineer's role in such illumination schemes.
According to daylighting expert Dr. Pekka Hakkarainen, director of technology and business development with Coopersburg, Pa.-based Lutron Electronics Co., the definition we're really talking about, as far as consulting engineers are concerned, is the ability to adapt electric lighting in the presense of daylight.
Hakkarainen, who recently spoke before the Emerging Technologies in Energy Efficiency Summit in California, explains the basic components of a typical daylighting system consist of smart ballasts and sensors, including photocells, infrared receivers, occupant sensors and wall-station controls, and finally the control device itself, which runs the algorithm. In a nutshell, he says, such a smart lighting control system should collect data from these interconnected sensors, but then interpret this information and transmit that information to other ballasts to adjust light levels accordingly.
Hakkarainen offers this advice:- Be aware of systems that use exterior vs. interior sensors. The latter, he argues, require lower maintenance and offer better local response.
- Understand the operating principles of sensors—how they work; what kind of features they offer; whether they're good; and most importantly, where to put them. "If a sensor is properly placed, the illumination corresponds with the task. If more light shines on the sensor, the less electric light required," said Hakkarainen.
- Optional, but often useful, is an understanding of the algorithm schemes used in the control devices.
According to Hakkarainen's colleague, David Bennett, manager of commercial marketing, the need to control electric light in the presence of daylight will only continue to grow for three major reasons:
- LEED
- Emerging energy codes
- An emphasis from owners to make spaces more comfortable.
The good news, adds Hakkarainen, is that current technology, particularly regarding addressable ballasts, accommodate an expansion of daylighting control, even if it's not part of the initial scheme.
"I really think the pairing of daylighting and addressable ballasts will have the biggest impact on the design community," he says.
Bennett adds system control flexibility is key, as a switching system for even greater control, such as time-clock management, or occupancy schedules, can also be easily and reasonably added.
"Our approach is to go on a fixture-by-fixture or room-by-room basis. This way if you can identify the human comfort level, it's easy to adapt the lighting control," says Bennett.
For a white paper on electric lighting control and daylighting visit the Lighting community at www.csemag.com.
