The days of the simple dimmer switch being thought of as lighting control are long gone. LED technology now enables total control of solid-state lighting characteristics, including light intensity, color temperature, hue, power consumption, and more. And with these more sophisticated lighting controls, the value received from LED lighting has grown significantly.
For example, the power needed to light the average office building typically accounts for 60 percent of the electric bill and 40 percent of the total energy cost. Office lighting also incurs many indirect costs such as maintenance, replacement and the additional cooling needed to offset the heat generated by incandescent lighting. LED lighting not only reduces overall energy consumption, but implementing smart lighting controls gives the building occupant or owner the ability to gain even greater financial savings by enabling specialty lighting applications.
Traditionally, there have been four basic approaches to lighting control:
- Manual: The simplest controls are an on/off switch or a manually controlled dimmer switch.
- Timer controls: Scheduled lighting controls are a simple, energy-saving strategy, either dimming or turning off lights outside of business hours.
- Occupancy controls: Many office buildings are equipped with lighting controls that detect room occupancy, usually using motion sensors.
- Light harvesting: This is a newer lighting control strategy that senses ambient light and adjusts room lighting accordingly, e.g. less artificial lighting is required in a well-lit room on a sunny day.
All of these approaches use a localized device or system to control on a room-to-room basis. This is old school, limited lighting control. Real energy savings come when an entire suite, floor or building can be controlled and analyzed for lighting and energy optimization. Then the elements used in lighting control can provide input to controls for other energy hungry systems such as heating or air conditioning. When systems begin to link, you can substantially increase energy savings.
The difference is in the LEDs
To implement smart lighting, you have to start with programmable light fixtures.
As with any computer chip, solid-state LED fixtures should be thought of as flexible devices that can be readily tuned. For example, LED fixtures can be tuned to deliver unique lumen outputs, which is ideal for matching newer LED fixtures with older, less-efficient luminaires. Individual programmable LED fixtures also can be tuned for color, making it easier to match hues or adjust for unique lighting situations. And LED fixtures can be tuned via controls for a unique electrical profile, decreasing energy costs and extending the lifetime of the fixture.
This tuning, referred to as programmability, makes it possible to adjust LED fixtures for specific installations or applications, which is particularly valuable for OEMs. One of the challenges that today´s luminaire vendors face is how to differentiate their lighting products, especially when they all use the same solid-state lighting components with similar performance characteristics. Programmable LED drivers and modules make it possible to customize light fixtures with value-added capabilities.
Once these customization capabilities have been added to luminaires, the next question is what is the best way to program and manage LED lighting? Is it best to keep this lighting control functionality localized or centralize control? Distribute the intelligence like the internet, or amass it in a single location like a telephone switch?
Where to place the brains for smart lighting
With the advent of new, lower power and lower cost semiconductors, on-board intelligence can be provided simply and be significantly easier to operate. For example, replacement LED drivers can be tuned for intensity and hue when they are installed to match adjacent installed lights. Fulham´s programmable LED drivers, for example, can be configured using a handheld programmer that can set such characteristics as the output current, dimming curve, and lowest dimming percentage. The result is a better aesthetic for lighting at all power levels, as well as greater consistency of lumen output.
Increasingly, the industry is calling these types of programmable LED drivers “clever” lighting solutions; they have features that can be modified using software embedded in the driver itself. Supporting LED driver programmability is only the first step in implementing a smart lighting strategy. Beyond clever, smart or intelligent lighting requires connecting the luminaires to a central server or internet cloud that can be accessed via smart phone or web browser. The operational functions are embedded in the LED light fixture itself, but the smart lighting control data is centralized and available for additional analysis and optimization.
For many lighting professionals, this raises the question of where to place the control interface. Does it make more sense to localize lighting controls using a “one-to-many” power control module, similar to what is used now for light harvesting, or do you include lighting as part of a building automation system, using IoT protocols or other standards to centralize control?
The approach with the lowest initial cost and least amount of flexibility is to use a single centralized hardware-based controller to manage multiple LED fixtures, e.g., for a single room. With this strategy, you use the onboard intelligence in the LED fixture to program the devices once, giving the controller limited light control capabilities, such as dimming. Of course, it´s more complicated to wire and maintain a single controller, since you are wiring multiple lights to a single device. This one-to-many approach also makes it significantly more difficult to make changes to light groups or to add future functionality. And it means you have a central point of failure: the controller.
Better energy management
Installing an overall building automation control system can have more initial cost, but offers greater mid-term and long-term flexibility. By harnessing the intelligence in every LED fixture unit, you create smart, tunable end points that can be individually controlled. This not only provides better energy management but also centralizes control of light tuning so you can adjust specific fixtures or tune the light for an entire space. For example, you can link specific lights to respond to motion sensors or an alarm or emergency signal. You also can easily add light sensors near exterior windows to measure ambient light and harvest this light by reducing the output of your light fixtures while adjusting the output of the HVAC system. And centralized lighting controls provide more detailed data about power consumption and LED driver performance to monitor energy savings and provide a warning when a light is ready to fail.
Unfortunately, integrating lighting controls into today´s building automation systems is still problematic. There are multiple standards for managing lighting controls and they aren´t all adaptable to building automation. In a future article, we will discuss the dueling lighting controls standards and how to choose the right integration approach to get the most from smart lighting.
Written by Russ Sharer, Vice President of Global Marketing and Business Development for Fulham Co., Inc.