Reported May 2007

BACKGROUND: Scientists at Rensselaer Polytechnic Institute’s Lighting Research Center have developed a simple, cost-effective, energy-saving device designed to harvest daylight automatically. Unlike traditional systems where one sensor controls many lamps at once, the Dayswitch controls light fixtures individually, providing flexibility for on/off control and simple installation.

ABOUT DAYSWITCH: The Dayswitch eliminates wasted or unwanted electric light by sensing when enough daylight is available to take the place of electric light, and then responds by turning off the fixture. When daylight decreases, the device turns the light back on. A built-in microcontroller automatically calibrates the Dayswitch, allowing for easy installation and maintenance. Although it’s made for office buildings with large sunlit spaces – such as at the concourse of a mall – the Dayswitch system can be installed anywhere, including private homes. It can even be more energy-efficient in homes, since most homes use incandescent lamps, which require more energy than fluorescent lamps.

LET THERE BE LIGHT: Typical daylight harvesting systems include a photosensor paired with a dimming ballast – a device that regulates the electricity supplied to a lamp -- to control fluorescent lighting, dimming or brightening the lights according to the amount of daylight entering the workspace. However, full-dimming ballasts are expensive, and photosensors are difficult to program and install. Dayswitch works with all conventional fluorescent ballasts, and has simple circuitry and on/off operation, making it less expensive than similar daylight control systems.

SENSORY FEEDBACK: A sensor is a type of transducer: an electronic device that converts energy from one form to another. For instance, microphones convert sound waves into electrical signals, while speakers receive the electrical signals and convert them back into sound waves. There are many different kinds of sensors, but most are electrical or electronic. A photosensor is an electronic component that detects the presence of various wavelengths of light: visible, infrared, or ultraviolet for example. The electrical conductance will change in response to the intensity of the light being detected, and this change is recorded by a computer.

The Optical Society of America contributed to the information contained in the TV portion of this report.

If you would like more information, please contact:

Optical Society of America
Washington, DC 20036-1023
202-223-8130
http://www.osa.org
info@osa.org

DID YOU KNOW?

Lighting accounts for one-quarter of the total energy consumed by US commercial businesses. Dayswitch could reduce lighting energy consumption by as much as 30%.

ON THE WEB...

Press Release: Scientists Develop Simple Alternative for Harvesting Daylight and Saving Energy

RPI's Daylight Dividends Program