Craig DiLouie, LC recently interviewed Charles Knuffke, WattStopper VP of Systems & Evangelist for an article about controlling LED lighting for an article for tED Magazine. The interview is published in its entirety below.
DiLouie: How are LED sources different from traditional sources in terms of controllability and behavior while controlled?
Knuffke: “Controllability” may be a confusing term to use, as it could be taken to mean the hardware that controls LED lighting, or it could mean the output of the LED source itself.
If the question is about the general controllability of the LED compared to other sources, such as fluorescent or compact fluorescents, for most of the fixtures we encounter LEDs offer excellent controllability. There is little to no startup delay, no issues with flickering, none of the “socket/ballast” compatibility issues we’ve seen with dimmable fluorescents. And as a manufacturer of occupancy sensors, LEDs offer huge benefits over other sources in that there’s is no reduction of lamp life if they are switched on and off repeatedly. That’s why the freezer cases in many grocery stores use LED strips with a short time delay occupancy sensor mounted on the top of the case.
As a controls manufacturer, when asked about the controllability of an LED source I’m usually thinking that the question is about the ability to alter the light output of the LED. To answer that I’m going to ask several follow up questions to make sure I’m able to provide the proper hardware to control the LED… How does the manufacturer intend the source to be controlled? To control the LED’s light output, is there an input to for a 0-10V signal, a DMX signal, or a DALI signal? If none of these, does the manufacturer recommend controlling the LED with a forward or reverse phase dimmer? Hopefully the manufacturer has made it clear how to best control the output of the fixture.
DiLouie: What opportunities (and problems) occur as a result of how controllable LED sources are and how they behave while controlled?
Knuffke: We’ve seen little issue with the general controllability of LEDs as long as manufacturer’s make it clear what method should be used to dim the fixture.
DiLouie: What are the top three technology trends impacting lighting controls for LED sources?
Knuffke: 1) The ability to provide dimmable fixtures at price points that meet those for standard on/off or bi-level fixtures.
In the case of California, there was considerable concern that the Title 24 Energy Code’s required fluorescent and LED general lighting in spaces over 100 sqft and with general LPDs over .5 w/sqft must be dimmable. Luckily by the time the code took effect, LEDs with dimming capability were so widely available and so cost competitive that meeting this requirement was rarely an issue. I think few folks in California expected the LED revolution to be this far along when the code was being debated.
2) The combination of increased light output while reducing lighting wattage that can be achieved by using LED fixtures. With lighting power being so significantly reduced, other building loads are now being considered for control since they represent a larger portion of the overall electrical usage (such as plug loads).
3) LED fixtures that offer the option to manually or dynamically adjust the Kelvin temperature of their light. While color changing for “Architainment” may be applicable for some limited number of spaces (retail for instance), its use in others will probably be limited. If however convincing research can be provided that there are significant health and/or productivity enhancements with “Human Centric Lighting”, we’ll be seeing significant demand for this type of lighting in many spaces – hospitals, education, and commercial spaces.
4) You didn’t ask for a fourth trend, but I couldn’t resist adding the potential for “LiFi” to change our lives in the future. This isn’t a lighting technology – it’s advancing a different technology using light. The idea of using lighting as a connection point to the building’s IT network, especially if it has the possibility of exceeding speeds currently offered by WiFi is incredibly exciting.
DiLouie: LED luminaires are more often installed in new construction, where energy codes mandate a broad palette of lighting controls. This means LED sources and more sophisticated control systems are advancing hand in hand. How has this impacted development of LED products and controls?
Knuffke: The biggest impact LEDs have had on controls manufacturers is to remind us that there are endless possibilities on where LED applications and technologies will go in the future, and so we’ve got to be open to considering completely different uses for our products. We’ve got to leave the comfort of the control world we’ve known, because there’s no telling where our customers will want to go in the future.
I’ve joked in the past that for my first 15 years in the industry (primarily selling relay panels solutions), all I ever had to worry about was creating a smarter timeclock. Compare that to the last five years, when the entire lighting industry has gone fractal by moving in so many different directions primarily based on the new silicon platform. I know very few people who say they know what lies ahead for our industry. The technology has completely changed, and functionality that was either limited or none existent is now being widely promoted. When your business is all about providing controls for LED light sources, there is bound to be quite a few sleepless nights thinking about your company’s roadmap.
DiLouie: What should specifiers be doing to go beyond code and take advantage of the controllability of LEDs?
Knuffke: Many of us focus on the energy codes, and that means we’re focusing on reducing wattage and ensuring that the lights are off when not needed. This is the road we’ve been on for the last 20+ years. LEDs are having a significant impact on both these as aspects, through their excellent ability to be dimmed, their ability to be turned on and off repeatedly without reducing the life of the fixture, and their higher lighting efficacy. So what is the next road that we’ll be asked to focus on?
I’m going to say the next challenges are going to be about data – specifically about getting, sharing, and making visual information about occupancy and power consumption information. Think about it – every building out there has lighting of some sort installed in it. If you wanted to build an infrastructure to communicate data about how the building is being used, the most logical path to start with is the lighting system.
So what should specifiers be doing? Even in areas where there is no mandate to install networked lighting and controls, they should be looking at what is being offered in the marketplace, and start trying out different types of networked lighting and control systems. Get their clients to understand that this is where we’re all going, and that the sooner they start to build competency in integrating their lighting and IT systems, the better off they’ll be. It doesn’t have to be the entire building, but they should be looking at setting aside a few areas in their buildings to prototype advanced lighting and control systems – because soon enough data about what is happening in their buildings is going to be an expectation of every building.
DiLouie: LED lamps and to an extent luminaires are being retrofitted into existing buildings. Controls, however, are often left out of conventional lighting retrofits. Has LED penetration into the existing construction market created new opportunities for lighting controls that previously were less available?
Knuffke: Absolutely – manufacturers understand that LEDs are the “go to” light source for replacement of existing lamps and luminaires, and so that’s where they’re focusing their efforts. Manufacturers are building fixtures with integrated controls, or making them ready for future control opportunity.
The Philips Hue lamp served as a wakeup call to everyone in the industry – here was a single replacement lamp that homeowners could install on their own that included remote controllability and color changeability, at a price premium over standard lamps. It was a single product case study showing that customers would consider lighting and controls as a single package.
DiLouie: A number of luminaire manufacturers now offer integrated control packages. Is this having an appreciable effect on the lighting controls industry, and if so, what is that effect? What is likely the long term?
Knuffke: When multiple manufacturers start offering integrated control packages, it sends a pretty strong message to the marketplace that controls are important. So if controls are important, the question is whether you want to be tied to someone that does controls as a secondary focus, or whether you want to use products from a manufacturer whose primary focus is controls and who can work with any manufacturer of lighting.
With manufacturing of Advanced Networked Lighting Controls now requiring expertise in multiple communication protocols, integration to other systems, and network security, you’ve got to ask who your controls partner will be moving forward – a luminaire manufacturer, or a company who specializes in controls.
DiLouie: LED lighting presents such a small load that the economic argument for lighting controls is more likely to be challenged. Assuming an LED future, what energy-saving control strategies are considered essential and therefore likely to endure? Will any fall away due to lack of cost-effectiveness?
Knuffke: I doubt that we’ll ever get to a point where the basic elements in the energy codes will go away – an area control device will always be needed so an occupant can turn their lights off, a shut off device (occupancy sensor for instance) will be needed to turn the fixture off when no one is in the space, and the general lighting will have to have a multi-level requirement which will be no issue with LEDs since they’re easily provided with a dimmable interface.
I do believe that other energy code requirements will be reviewed to see if they are still economically viable, and we may see some of these requirements “de-emphasized” or removed, and possibly replaced with other requirements such as demand response and/or the ability for the lighting systems to provide data to the system owners.
DiLouie: With LED, lighting controls can go far beyond energy savings. Lighting controls can respond to individual occupants and completely transform a workspace. What are these capabilities, and how would you characterize demand for them?
Knuffke: There are several capabilities that come immediately to mind, with color tuning being at the top of the list. Demand is small right now, but if more research is done to back up possible performance and health benefits, demand will increase significantly.
There’s also several discussions about the level of granularity that should be employed with lighting controls – some folks are pushing for individual fixture control while others believing that zone control (control of multiple fixtures together) make more sense economically. I can state that the first installation of individually controlled fixtures that I was involved in back in 2004 proved to be very difficult for the owner to manage. No one in the building wanted to take responsibility for programming groups and scenes for ~480 individual fixtures (control points) over two relatively small floors. While the engineering staff in a Class A building would be able to manage that sort of a system, who would be able to keep that sort of a control scheme working for a Class B or C type building? Just because something is possible doesn’t always mean it right for that customer.
DiLouie: What should distributors be doing right now to maximize the value they offer to their customers when lighting controls are included in a project?
Knuffke: Start by asking their customers what products and control systems they are currently using, and learn everything they can about these systems. Make sure to stock the more commonly used components so if project needs change, no one has to wait for new components to be shipped out from the manufacturer.
Controls and Lighting is getting so complex and is changing so rapidly that the smarter distributors are appointing product specialists whose responsibility is working closely with the manufacturers and/or local lighting reps, and then offering training on these topics to their customers. There’s a huge opportunity to become more valuable to their customers (end users and contractors) by being recognized for their product skills and educational programs.
We’ve also having to learn entire new ways of comparing products – in the past incandescent were rated according to their wattage, not lumen output. LEDs have completely changed the way we will be talking about lighting, and whenever there is confusion, there is an opportunity for education.
DiLouie: If you could tell the entire electrical industry just one thing about controlling LED lighting, what would it be?
Knuffke: There’s so much to learn about LEDs, if you haven’t already started learning about them, or plan to immediately, you’re going to be left behind.
DiLouie: Is there anything else you’d like to add about this topic?
Knuffke: Be careful with current draw on some LED fixtures – the initial draw may be much higher than the fixture’s rating.
I was just on a project where a breaker on an inverter kept tripping whenever a string of exterior LED fixtures was turned on. The lighting load was less than the breaker’s rating, so there shouldn’t have been an issue there. The contractor thought the problem was caused by a relay that was controlling the loads, but I explained to them the relay was a dry contact closure and not affecting the circuit at all. They finally called the LED fixture manufacturer and found out that their fixtures had a high inrush current, and that was what was causing the breaker to trip.