Use Daylight Harvesting for Free Light


Property managers and boards are always searching for ways to reduce common area energy costs. Most buildings have implemented the change from T-12 magnetic ballast lighting to T-8 electronic. Others are taking advantage of LED lamps, occupancy sensors, CO detection for the garage fan controls and variable speed drives for the building’s motors. Another unique option for harvesting energy is to utilize the daylight pouring in through the windows. The basic concept of Daylight Harvesting is fairly simple. When sufficient daylight is available, the artificial lights either automatically turn off or dim to the appropriate level. The possible savings from a proper installation are impressive.

Most of the requests we receive for this type of technology are in lobby or pool areas
where a whole wall is often composed of floor to ceiling glass. In a recent application, the
custodial staff used  a series of switches to turn the pool area lights off at the end
of the day, and back on in the morning. The property manager was looking for a solution
to eliminate the need for this step, adding the ability to automatically reduce the number
of fixtures in use during daytime operation while further reducing energy costs.

The solution was to install a switching photosensor in conjunction with a series of relays,
which would adjust the  lighting levels without the need for manual changes. Equipped
with a sensor containing an advanced digital multi-band photosensor, an on-board
microcontroller, and an LCD display, the sensor can easily be adjusted to the appropriate
lighting level.

The cost of these installations can be fairly reasonable, assuming the path of
low voltage cable from the sensor to the local switches or breaker panel can be easily

In this particular installation, we also used a 24-hour timer that would override the
system, turning the lights off when the pool is closed and back on the following day.
For this customer, all of this switching is now automated, eliminating the need for staff

Please feel free to contact us if this type of solution sounds suitable for your property.

Yours in energy management.