This piece was originally published in the March/April 2020 issue of electroindustry.
by Steve Mesh, Principal, Lighting Education & Design
Mr. Mesh teaches a full-day class on networked lighting controls on behalf of the DesignLights Consortium (DLC)
Lighting controls save energy. That’s why many electric utility companies incentivize people for installing them, and, in some cases, they also incentivize manufacturers for making them. Any time a control device switches off or dims a light, it
reduces energy use. Saving energy (and therefore money) is a great reason to install lighting control devices or systems.
There has been a rapid expansion of incentive offerings for networked lighting control (NLC) systems among utilities throughout the country. They know that NLC systems are the “next big thing” to hit the market. As incentives for older technology
(such as compact fluorescent lamps and wallbox occupancy sensors) are starting to go away, the utilities want new arrows in their quiver. NLC systems represent a major new opportunity.
Ironically, lighting power densities (LPDs) are rapidly decreasing and, as a result, the opportunities for saving energy are diminishing. Some industry experts have recently called for an end to energy codes altogether for this reason. As the financial
argument for deploying lighting control devices or networked lighting control systems changes, what else can justify the use of this equipment? Answer: Non-energy benefits!
NLC systems are computer networks that happen to control light fixtures. Since these networks are digital, it means they are designed with the express intention of transmitting data. Fundamentally, these systems must transmit native commands telling light
fixtures to turn on, dim, or turn off based on schedules, or based on input from occupancy sensors, photosensors, or switches. Increasingly, however, NLC systems are designed with the expectation that data from light fixtures, sensors, and switches
will be shared. Many systems now have options for interfacing with other building systems using the BACnet protocol (and others). Additionally, the advent of true Internet of Things (IoT) architecture means that NLC systems will increasingly be able
to interface with— theoretically—anything.
What kinds of non-energy benefits are either currently offered or are in the works?
Some systems enable the user to determine where specific pieces of equipment (or even people) are within a facility. For example, some hospitals now equip things like wheelchairs or even crash carts with a discoverable “tag.” This type of
system allows staff to immediately locate items that may be critically needed. One hospital gives doctors as well as patients similar tags. Their policy is that an exam cannot commence until three things are present in the appropriate exam room: 1.)
doctor, 2.) patient, 3.) required diagnostic or other equipment. That policy helps to reduce wasted time— and remember, time equals money. These systems may use protocols such as Bluetooth or Bluetooth Low Energy (BLE) to discover the tags.
Even if the NLC doesn’t use Bluetooth protocol to communicate with the light fixtures, sensors, and switches, the Bluetooth technology may piggyback on the fixtures. After all, light fixtures always have some source of power needed to run the
Bluetooth network as well. And light fixtures are in every space in every building. So, it’s a great match.
These days, you probably get around by using a global positioning system (GPS). Your car (or phone, for that matter) is a GPS receiver that takes signals from a handful of satellites to triangulate your position anywhere on the planet. What if this kind
of triangulation could be deployed indoors? It can. The ubiquity of light fixtures throughout every space ensures that the lighting system is the perfect vehicle for creating the means to provide this triangulation indoors. This might be useful in
a large space such as a warehouse, big-box retail store, or distribution center. This functionality might also be “piggybacked” by adding appropriate circuitry or equipment into light fixtures and/or NLC systems to provide this function.
Diagnostics and Reporting/Alerting
Many NLC systems currently on the market have diagnostic and reporting/alerting functions. Diagnostics are typically ongoing. For example, standalone ceiling-mounted occupancy sensors used in a wireless control system are usually battery-powered. Instead
of waiting for the battery to die, rendering the functionality of the sensor useless, some systems continuously monitor the signal from the sensor, which can then alert maintenance staff when the battery output is very low. At that point, they can
head directly to the sensor in question and change the battery, avoiding sensor downtime, which might potentially increase light levels, load, and electricity use. The same type of ongoing diagnostics and reporting/alerting also happens for light
fixtures and other devices used by the system. In an outdoor lighting system, monitoring and reporting on malfunctioning fixtures have the added benefit of improving the safety of drivers and/ or pedestrians by allowing maintenance staff to quickly
locate the equipment in question and repair or replace it.
Conference Room Scheduling
If a scheduling system can interface with a lighting control system, light fixtures and occupancy sensors can help staff know when a conference room is free or alert people already in the room that another group is coming in soon. For example, the scheduling
software can send instructions to turn the lights on in the room a few minutes before the scheduled use. It might also send instructions to lower shades (if needed for A/V reasons), or even to change the temperature setpoint on the HVAC system—then
revert the shades and/or HVAC system back after that group leaves. It might blink or dim light fixtures five minutes before the next group comes in as a reminder that they must vacate the room shortly. This is getting into the realm of IoT,
where diverse building systems must be able to interface—either with each other or even with non-building systems (e.g., with a software-based companywide scheduling system that isn’t typically designed to “talk” with building
Integration with HVAC/BMS/Other Systems
As mentioned, NLC systems are increasingly being offered with options to talk BACnet (or other protocols) so they can interface with other building controls. That might be an HVAC system (for example, so both the HVAC and lighting systems can use
the input from only one occupancy sensor). It might be a more comprehensive building management system. Another option that is being offered by some NLCs is the ability to interface with an “Automated Demand Response” (ADR) server.
In at least one currently available NLC system, other equipment on-site talks with the ADR server, which is usually run by a third party and is off-site. That on-site equipment then connects via low-voltage wires to the NLC, sending a simple signal
that says “there is now a demand response event— change all lighting to levels as pre-programmed for the demand response event.” In other systems, all that’s needed is to enter the URL for the ADR server. The functionality
is the same. In certain locations, there are code requirements to use equipment with provisions to enable at least a 15 percent reduction in lighting power—automatically—based on the signal from the ADR server. Typically, fixtures must
be dimmed by at least 20-30 percent before the average person can perceive the reduction. So, even if your utility doesn’t offer a financial incentive for tying into an ADR server for your area, it may still pay by reducing lighting loads during
times of peak demand. In most commercial and industrial buildings, evening out the load profile is typically a way to save energy and money even if you’re not participating in an incentive program. ei
Editor’s Note: This article was originally published at the Lighting Controls Association’s website at www.LightingControlsAssociation.org.
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