Everyone knows that if there’s available daylight, keeping lights off saves lots of energy. Up to 40 – 60% of lighting energy. But turning lights off to compensate for available ambient light is complicated and often easier said than done in large industrial facilities.
In a facility with skylights, windows, sidelights, clerestory windows, or the occasional open docks and bays, you have available daylight, which varies according to time of day, weather conditions and more. Areas that get light from those sources don’t necessarily need much artificial light – at least not during the day – but areas farther from those sources do. The problem is in a large site with thousands of square feet of space. Managing each fixture’s light output to compensate for the changing amounts of ambient light during the day is an enormous challenge and is impossible to do manually.
To date, facility managers trying to take advantage of daylight have looked to external daylight harvesting sensors that attach to groups of lights. These after-market offerings can provide incremental energy reductions, but still leave substantial savings on the table and have a number of performance issues that result in over- or under-lit areas and jarring jumps or drops in light levels. Not to mention that these sensors can be difficult to configure and are prone to implementation issues. Just check search for ‘daylight harvesting commissioning guide’ or for a tutorial on how to set this up and you’ll understand more. It’s high-order math for modest gains.
But there is a better way. It is possible to take full advantage of ambient daylight, manage light levels, and see exactly how much lighting energy is being saved. That is the approach Digital Lumens has taken with its latest additions to the Intelligent Lighting System, which integrate daylight sensing into every fixture. This approach delivers much higher energy savings and improved functionality because each fixture intelligently measures available ambient light and gradually adjusts light output to maintain desired light levels.
Easy to configure and manage, the Digital Lumens daylight harvesting functionality also provides an easy interface for controlling fixtures and reporting on savings. Do you want to know how much money and energy you’ve saved in your facility? That information is readily available. Do you want to change your target light levels? It’s at your fingertips; you don’t need to get up on a lift and adjust dipswitches on sensors controlling 100+ fixtures.
So how much energy does daylight harvesting actually save? In addition to the energy savings that Digital Lumens delivers by providing light when and where it is needed – up to 90% — daylight harvesting can save an additional 25-50% depending on the amount of ambient light available.
We will continue to delve into daylight harvesting and other savings opportunities in future posts. In the meantime, if there are other topics you’re interested in, please let us know by sending us a note at firstname.lastname@example.org.