Rensselaer Research Review Spring/Summer 2010
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*  DaySwitch® Demonstrates Simple Daylight Harvesting Technology to Save Energy

There are three main components to the DaySwitch: the sensor module, the control module, and a remote commissioning device.

How the DaySwitch Works

There are three main components to the DaySwitch: the sensor module, the control module, and a remote commissioning device. A built-in microcontroller automatically calibrates the DaySwitch, allowing for easy setup, according to LRC researchers. The DaySwitch senses when sufficient daylight is available to take the place of the electric light in the space and turns off the light fixture. When daylight decreases below the set point, the device switches the electric light back on. To install the DaySwitch, the microcontroller is mounted inside the luminaire to switch the lamps on and off. The photosensor is connected to the micro-controller via wires and is mounted outside the luminaire to monitor daylight levels in the space.

“The field test results support the use of the DaySwitch as an alternative to the existing lighting dimming control technologies that are expensive and difficult to commission,” said Jennifer Brons, LRC research scientist and DELTA Program manager. “The feedback we gathered has enabled us to identify applications where the DaySwitch will be most effective in saving energy associated with turning off unnecessary electric lighting.”

Study Findings

  • The DaySwitch provided the most energy savings in large open spaces with plentiful daylight, high luminaire wattages, and long hours of use.
  • Commissioning was hassle-free, requiring only about 30 seconds per DaySwitch.
  • The DaySwitch worked as intended by automatically switching off lights when sufficient daylight was available.
  • Feedback from most occupants was generally neutral or positive. There were a few occupants of private offices who objected to automatic switching.
  • Private offices showed little or no energy savings because of minimal daylight availability (blinds, window tinting, and obstructions), low luminaire wattages, short hours of occupancy, and manual operation of a wall switch. Some private offices on the campus were over-lighted, which reduced the ability to switch off the lights because the Dayswitch determines its switching threshold as a function of the measured electric light level.

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