Lighting accounts for a quarter of the total energy consumed by U.S. commercial businesses, according to the United States Department of Energy. The DaySwitch could reduce lighting energy consumption by up to 30 percent in buildings with sufficient windows or skylights. Developed by Rensselaer Polytechnic Institute’s Lighting Research Center (LRC), the DaySwitch senses when there’s enough daylight available to replace electric light and turns off fixtures. When daylight decreases, it turns the lights back on.
Traditional dimming ballast systems do the same thing by reducing lamp current to adjust light levels. But they’re expensive, and their photosensors are difficult to program and install. Meanwhile, the DaySwitch controls individual light fixtures. Its design also makes production less expensive. And, its built-in microcontroller enables self-commissioning and easy installation and maintenance. Together with the microcontroller, its light-to-frequency diode provides accuracy from 1 to 12,000 lux.
The DaySwitch works with all conventional fluorescent ballasts, which regulate voltage and current supplied to the lamp. The researchers say that commercial businesses can recoup the DaySwitch expenses in energy savings within two to five years in retrofit applications. Building the DaySwitch into new construction yields a one- to three-year payback. The New York State Energy Research and Development Authority has given the LRC a $198,745 award to further develop and commercialize the device.
Rennselaer Polytechnic Institute
www.rpi.edu