As LEDs continue to mature, the advantages they offer become more pronounced. But they are not yet a universal solution for new construction or retrofits, so facility managers find themselves needing to use a combination of different types of lighting to meet their needs.
For example, in an office building, there may be high-pressure sodium lights in the parking lot, metal halide downlights in the lobby, and fluorescents in the lunchroom and office spaces. Could you replace all those with LEDs? Yes. But the question of whether you should has to be answered first, says Eric Richman, senior research engineer, Pacific Northwest National Laboratory.
"It's not always just a slam dunk to say 'oh, LED will solve all our problems,'" he says. In that theoretical office building, "there are four different cases and all have different characteristics."
The odds are that you're going to end up with different types of lighting based on the characteristics of your spaces, and you might even end up with different types of LEDs. Where these differences between different LEDs and different types of lighting overall can become a big challenge is in the control of the lights. Fluorescents operate differently than metal halides, which operate differently than LEDs, so those differences need to be worked out for the lights to be controlled by one system. While dimming capability is a common feature of LEDs, not all LEDs work the same way and not all can be used with the same type of dimming. With dimming becoming a more common way to save energy, take advantage of daylighting and demand response opportunities, and even meet code requirements, managing different LEDs and different types of lighting takes on greater importance.
Managing controls for different types of lighting may seem like a daunting task when you first start considering how many different ballasts, drivers, sensors, and control schemes may be involved in a facility. It certainly can be done, but it does require paying close attention to a few things, including what you need your lights to do, what space you need them in, and how energy efficiency efforts and energy codes require lighting to be controlled.
With the advent of LEDs, the options for control strategies and more precise control keep improving, says Gabe Arnold, market strategies program manager, Northeast Energy Efficiency Partnerships.
"We're seeing integration between controls and the source technology in a way that we never saw before, and I think a lot of that is due to LED technology and the ease with which it can be integrated with controls," he says.
But, a cautionary note: Not every LED works with controls the same way, and there's no guarantee that you'll be able to simply drop in whichever LED you want and have it work with your controls. Dimming capability is a strong selling point for LEDs, but Richman points out that it's not always as simple as installing an LED and gaining instant dimming capability.
"You can't stick any old LED on a typical dimmer circuit and expect it to work," says Richman. "It may work, it may work well in a certain range, it may not work at all. Unlike the fluorescent industry where they've kind of settled on how to make sure you can dim the product — at least to most users' satisfaction — that hasn't quite been nailed down for LEDs."
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