DaySwitch™ Adjusts Lighting Per Daylight Availability
The DaySwitch™, developed by Rensselaer Polytechnic Institute,
consists of a photosensor that measures daylight levels and sends a signal to
the switch to turn off the electric light as the sunlight gets bright enough --
an ultra-simple solution to wasted electricity.
TROY, NY, USA -- Scientists at Rensselaer Polytechnic Institute’s Lighting
Research Center (LRC) have developed a simple, cost-effective, energy-saving
device designed to take advantage of daylight automatically.
“The DaySwitch™ is designed to build end-use efficiency by reducing light energy usage in commercial buildings and maintaining occupant satisfaction,” said Peter Morante, director of energy programs at the LRC. “It is estimated that the DaySwitch™ will be able to reduce lighting energy consumption by 30 percent in buildings with significant daylight contribution through windows or skylights, allowing for a payback period of approximately three years.” This is an on-the-cheap setup usable only where this exterior light is available.
Typical dimming systems have several drawbacks, including high initial cost and difficult photosensor programming and installation. As a result, dimming systems have not permeated the market, according to Morante.
The DaySwitch™ development team, led by Morante and Richard Pysar, an electronic design engineer at the LRC, created a low-cost prototype to control individual light fixtures, unlike traditional systems where one sensor controls numerous lamps. Individual control provides flexibility for on/off control and simple installation.
The DaySwitch™ works with all conventional fluorescent ballasts—the device regulating voltage and current supplied to the lamp. Because of its simple circuitry and on/off operation, the cost to produce the device is minimal and far less expensive than traditional daylighting control systems that utilize dimming ballasts, according to the LRC research team.
“The DaySwitch™ offers a low cost option for harvesting daylight that is simple, accurate, and convenient to install,” said Andrew Bierman, senior research scientist at the LRC. “By taking advantage of natural light and using systems like the DaySwitch™, we can significantly reduce energy consumption and the growing strain on the nation’s power grid.”
The United States Department of Energy estimates that lighting accounts for one-quarter of the total energy consumed by U.S. commercial businesses.
How the DaySwitch™ works
A built-in microcontroller automatically calibrates the DaySwitch™, allowing for self-commissioning and easy installation and maintenance. The design also includes a light-to-frequency photodiode that, together with the microcontroller, provides accuracy over a wide range of light levels (1 to 12,000 lux).
According to the LRC research team, commercial customers can expect a two- to five-year payback in retrofit applications and a one- to three-year payback when the DaySwitch™ is built into fixtures installed in new construction.
Initial research into simple concepts for daylight harvesting was funded by the Daylight Dividends program, a national effort, administered by the LRC, to educate and provide evidence, guidance, and perspectives supporting the use of daylighting in commercial and educational facilities. Daylight Dividends sponsors include California Energy Commission, Connecticut Light and Power Company, Efficiency Vermont, Iowa Energy Center, NYSERDA, North Carolina Daylighting Consortium, Northwest Energy Efficiency Alliance, and the U.S. Department of Energy. The initial research results are published in Lighting Research & Technology volume 37, issue 1.
The LRC also received a $75,000 Energy Innovations Small Grant (EISG) to develop the first DaySwitch™ prototype. EISG is a California Energy Commission Public Interest Energy Research (PIER) program designed to establish the feasibility of new, innovative energy concepts.
About the Lighting Research Center
Page posted by Sterling
D. Allan Apr. 25, 2006