Category: LED + SSL

DOE Publishes GATEWAY Report on Tunable Lighting in Three Texas Classrooms

The U.S. Department of Energy’s GATEWAY program has released a new report on a trial installation of tunable-white LED lighting systems in three classrooms in the Carrollton-Farmers Branch Independent School District in Carrollton, TX, which provides valuable insights into the use of this technology in a real-world setting.

The U.S. Department of Energy’s GATEWAY program has released a new report on a trial installation of tunable-white LED lighting systems in three classrooms in the Carrollton-Farmers Branch Independent School District in Carrollton, TX, which provides valuable insights into the use of this technology in a real-world setting.

The LED systems were installed in August 2016 and provide the ability to vary the spectral power distribution (SPD) across four preset conditions associated with nominal CCTs of 3000 K, 3500 K, 4200 K, and 5000 K. The controls also provide for preset scenes to vary the on/off status and dimming level of different luminaire zones within the room, to better support such classroom functions as audiovisual presentations.

Among the findings:

• The reduction in input power for the tunable-white LED lighting system was estimated to be 58% relative to the incumbent fluorescent system, and was attributable to the higher efficacy of the LED luminaires and a reduction in illuminances, which previously exceeded IES-recommended levels.
• Dimming furthered the energy savings in each classroom.
• While the teachers’ usage of the controls varied widely as recorded by the monitoring system, in each case the lighting consistently operated with all or some of the luminaires turned off or dimmed for portions of the school day.
• When the control locations were more easily accessed by the teacher, the dimming level was varied more regularly.
• The teachers used the scene controls regularly but used the SPD controls infrequently.
• Color consistency for the tunable-white LED luminaires was very good, even over the dimming range, with only minor variations in CCT and Duv.
• The two teachers interviewed by DOE appreciated the ability to tailor the lighting to different classroom needs, and felt that the lighting and controls allowed the students to be engaged in choosing the settings for various classroom activities. Both teachers stated that the lighting system improved the overall learning environment.

Click here to get the report.

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Presentation Proposals are Being Accepted for LEDucation 2018

LEDucation 2018 planning is in full swing and you are invited to share your knowledge and expertise on subjects related to and about LED Lighting. Speaking proposals are due November 19, 2017.

LEDucation 2018 planning is in full swing and you are invited to share your knowledge and expertise on subjects related to and about LED Lighting.

Speaking proposals are due November 19, 2017.

Click here to learn more.

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Tackling Flicker

Flicker is an old lighting issue diminished by the mass adoption of fluorescent electronic ballasts and returned with the advent of LED sources. Photometric flicker is the modulation of light source intensity or output over time. Here’s an update on industry efforts to tackle the challenge, with a focus on the recently published NEMA standard.

Below is an article I wrote for the October issue of tED Magazine about industry efforts to tackle the challenge of LED flicker, with a focus on the recently published NEMA standard. Reprinted with permission.

Flicker is an old lighting issue diminished by the mass adoption of fluorescent electronic ballasts and returned with the advent of LED sources. Photometric flicker is the modulation of light source intensity or output over time.

Flicker may be external or internal to the lighting system. It may be visible (present in an immobile light source observed by an immobile observer) or stroboscopic (visible or invisible, and perceptible if the light source or observer is in motion). And its effects range from irritating to impairment, in some cases even if it is not perceptible by users. Studied have linked it to eyestrain, blurred vision and impaired performance. A small percentage of people is particularly susceptible and may suffer headaches and migraines. Flicker may also be problematic for videoconference applications, which use cameras.

The problem with LEDs is that, unlike traditional sources, they have no persistence. This means changes in forward current results in a nearly instant change in light output, potentially making flicker more pronounced.

Dimming LEDs is particularly concerning. Phase-control dimmers, which chop the AC waveform to produce dimming, may cause LEDs to rapidly cycle and produce flicker. If flicker is present, dimming may also make it more visibly pronounced, as flicker is more noticeable at lower light levels.

Generally, LED products featuring high-quality drivers that are properly paired with compatible controls will not produce objectionable flicker. These drivers are typically larger and more costly, however. In particular, digital controls generally do not induce flicker in the LED lighting system. So to minimize flicker, the electrical installation should minimize potential for electrical noise (external cause), feature LED products with high-quality drivers, and feature dimming controls are that are either digital or confirmed as compatible with the LED product. For maximum assurance, a test installation may be beneficial. Flicker can be measured in the field using specially designed handheld meters.

Due to the importance of this issue, the lighting industry required metrics and guidelines to help electrical professionals evaluate and specify appropriate products. In 2015, the Institute of Electrical and Electronics Engineers (IEEE) published IEEE PAR1789-2015, providing recommendations for minimizing flicker based on existing flicker metrics. These recommendations can be summarized as three major application needs: prevent seizures among light-sensitive people, limit other biological effects, and prevent these other effects. For each, IEEE recommends maximum percent flicker based on frequency.

After IEEE published its recommendations, the National Electrical Manufacturers Association (NEMA) released a position paper stating the IEEE recommendation is overly stringent for many applications, which could result in unnecessary additional cost to products due to more robust electronics required. In April 2017, the National Electrical Manufacturers Association (NEMA) published NEMA 77-2017, a new standard recommending a method for quantifying visibility of temporal light artifacts such as flicker and recommending application-based limits. The measurement methods and recommendations are applicable to all types of lighting (lamps, luminaires, etc.) and controls, though control methods and recommendations are limited to phase-cut dimming. It addresses visibility among human observers with limited speeds of motion. It does not address interference with equipment such as cameras, nor stroboscopic flicker.

Standards provide manufacturers a basis for testing and reporting and electrical professionals a basis for product evaluation, comparison and application. Recommendations give electrical professionals guidance to properly select products. This is important to the industry because if a lighting installation suffers from objectionable flicker, and that flicker is part of the LED product’s normal operation, typically the only recourse is product replacement. For this reason, distributors should vet LED products as posing a low risk of producing flicker before commitment. New methods and recommendations provide valuable tools to facilitate this vetting.

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National Academy of Sciences Releases Report on Solid-State Lighting

The National Academy of Sciences, Engineering, and Medicine (NAS) has published a report, Assessment of Solid-State Lighting, Phase Two, which is a follow-up to its 2013 report. The new report…

The National Academy of Sciences, Engineering, and Medicine (NAS) has published a report, Assessment of Solid-State Lighting, Phase Two, which is a follow-up to its 2013 report.

The new report focuses on three key areas: commercialization (noting the rapid uptake of SSL since the 2013 report), technology development (updating the findings of the 2013 report), and manufacturing. In the process, the NAS committee has updated material that was presented in the earlier study.

Click here to read it.

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New Report Published on Color Shift Impact on Reliability

An industry working group facilitated by with the Department of Energy has published a new report on the impact of color shift on reliability. LED Luminaire Reliability: Impact of Color…

An industry working group facilitated by with the Department of Energy has published a new report on the impact of color shift on reliability. LED Luminaire Reliability: Impact of Color Shift was written to provide a better understanding of how and why color shifts. It does not define limits for specific applications.

Developed by the LED Systems Reliability Consortium (LSRC) under the auspices of the Next Generation Lighting Industry Alliance, it’s available here.

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DOE Publishes LIGHTFAIR International Presentations

At LIGHTFAIR 2017 in Philadelphia, DOE once again hosted an informational booth that offered free educational sessions to attendees. DOE has now made these presentations available for free download. They…

At LIGHTFAIR 2017 in Philadelphia, DOE once again hosted an informational booth that offered free educational sessions to attendees.

DOE has now made these presentations available for free download. They include:

Connected Lighting Systems Efforts
Michael Poplawski, PNNL

NGLS Competition One: Installation and Configuration Evaluations
Ruth Taylor, PNNL

There’s Something About Red: Applying TM-30 in Your Practice
Naomi Miller, PNNL

Many Shades of White: DOE SSL Explorations into Color Tuning
Andrea Wilkerson, PNNL

A Case of the Blues: Research Reveals Why Spectrum Alone is Not Enough
Bruce Kinzey, PNNL

Download them here.

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Acuity’s Dan Ryan on Bundling in Lighting Industry

I recently had the pleasure of interviewing Dan Ryan, VP Product, IoT Solutions, Acuity Brands Lighting. The topic: disruption in lighting, notably the current trend of “bundling,” which was the…

I recently had the pleasure of interviewing Dan Ryan, VP Product, IoT Solutions, Acuity Brands Lighting. The topic: disruption in lighting, notably the current trend of “bundling,” which was the subject of his presentation I caught at Strategies in Light. I’m happy to share his responses with you here. The interview informed an article I wrote for the July 2017 issue of tED.

DiLouie: What would you say is the thesis of your 2017 Strategies in Light talk?

Ryan: A great place to think through what will happen next in our industry is to map out how concepts from computing will transfer over to lighting and building automation. The intersection between the two is a great area to spot opportunities.

One famous pattern in the history of computing is best captured in a well-known quote that I really love, attributed to Jim Barksdale: “There are two ways to make money in business: You can unbundle, or you can bundle.”

Almost every major technological wave in computing included either a bundle or unbundle event. Microsoft dominated the pre-Internet computing era by bundling all of your applications onto Windows, and made a fortune. The internet came along and unbundled everything into a sort of chaos, until Google, Facebook, Amazon, and Apple and others emerged to re-bundle everything again. More recently, we’re seeing bits & pieces of these devices and services being siphoned off into discrete items – with products like Amazon’s Echo, Apple’s Earpods (unbundling audio), and Snapchat Spectacles. And there’s currently a sense that another huge unbundling event is about to happen with blockchains and cryptocurrencies.

My talk at SiL was looking at the bundling phenomenon and seeing whether it is a good framework for understanding what’s happening in lighting right now.

DiLouie: In your talk, you brought up the concept of bundling. What is bundling, and how did it play out in the example of smart phones?

Ryan: Bundling is exactly what you’d think – the tendency for products to be sold together in a package, vs sold discretely. 15 years ago, it would take an entire closet full of devices (video recorder, telephone, CD player, TV, laptop) to fulfill the functions that an iPhone can deliver today.

The economics behind bundling is a pretty complex topic, and the definitive piece on this was put together by Chris Dixon.

But the basic aspect is that there are powerful economic forces in play that benefit both buyers and sellers. Buyers get access to more services for a lower cost than they would if they purchased independently, and sellers gain more profits by selling to a larger customer base.

DiLouie: You said you see lighting as the new iPhone. How is bundling applying to the lighting industry right now?

Ryan: The world is starting to recognize that lighting is uniquely positioned to be an aggregation point for the delivery of IoT services – due to its ubiquity in the as-built environment, and the proliferation of networked lighting control systems. So you’re starting to see lighting companies bundle new digital services with lighting, with offers like indoor-positioning, asset-tracking, and occupancy analytics. And much like that closet full of consumer electronics that’s now bundled into an iPhone, you’re seeing a bunch of systems that used to be sold, installed, and maintained independently start to consolidate a single platform – smart lighting.

DiLouie: Lighting is moving beyond its core benefits to potentially offer an array of services. What are these potential services, and what services are being offered now?

Ryan: Indoor positioning has emerged as the early-leader, with significant deployments underway by the major players. Acuity has been a leader in this space, with over 50M sqft of indoor-positioning infrastructure already deployed. For customers switching over to LED, particularly in segments like retail stores, LED lighting simply offers the most cost effective and highest performance platform for providing location services. End-users are leveraging indoor-positioning to deliver a variety of value-added services, with things like shopper indoor-wayfinding, mobile-marketing, and location analytics.

More recently, both startups and established players are starting to explore how lights can act as sensors for other things. Examples of this range from asset-tracking solutions (for tracking the location of critical assets like patient-beds/wheelchairs in hospitals), and space utilization solutions that tap into existing lighting-control occupancy sensors.

The common pattern between all of these solutions is leveraging the lighting network to collect data about the environment, and then using that data to improve a business-process.

DiLouie: You brought up that consumer electronics is undergoing unbundling. How does this concept work, and how do you see it potentially applying to lighting in the future?

Ryan: You’re seeing a physical manifestation of unbundling happening right now. All the major tech companies are offering voice-assistant products, including Amazon Echo, Google Home, and whatever Apple is about to launch. This is taking a service that used to be bundled with your smartphone – a voice based assistant – and unbundling it into a single, discrete device. Amazon even took this a step further with the recent Echo Show product – which contains an app for making phone calls!

Right now, the lighting industry is going through a “bundling” phase, where IoT services as well as BMS are bundling with lighting projects, which is a trend that will continue for the foreseeable future. What I think will eventually change this is the desire for compatibility between different systems. Compatibility drives standardization, which drives competitive dynamics and opens up the opportunity for a new services layer. An independent services layer would allow individuals pieces to pull pulled off – and unbundle yet again!

But that’s still a few years out at least – although you are starting to see some initial momentum around industry standards for networking lighting systems, building automation, and sensor interfaces.

DiLouie: You stated that the impact on distribution matters more than product. What examples can you provide from the consumer electronics industry?

Ryan: My point here was that when people look at these big, disruptive technology shifts, most of the analysis is very product-centric. People very naturally focus on the things they see – Netflix, the Apple Watch, Snapchat Spectacles, Spotify, etc. But the real story is underneath in distribution – technological shifts that impact distribution are the real drivers. “Disruptive” products are merely symptoms of an underlying disruption in distribution.

Probably the example that hits closest to home is what’s currently happening to the cable TV industry. Before streaming-video over the Internet, it was basically impossible to get access to content outside of the cable bundle. Whoever had the local monopoly on the data-pipe to your home became the sole provider of content, so everyone got used to paying for 1000 different cable channels that they never watched.

Once it became feasible to stream video over the Internet, you saw the rise of all the standalone subscription services for video content, like Netflix, HBO GO, and Hulu. So by changing the distribution model for content from cable to the Internet, an unbundling event happened.

DiLouie: What impact do you see lighting technology bundling (and unbundling) having on traditional electrical distributors?

Ryan: The powerful economic principle behind bundling is that both buyers and sellers benefit. So in that sense, when you apply this to the lighting channel, electrical distributors will benefit. The sale of higher-end systems will lead to larger project sizes, and help fight the commoditization and price erosion that we’re currently seeing in the traditional lighting market.

DiLouie: What impact do you see lighting technology bundling (and unbundling) having on electrical contractors?

Ryan: One of the major product challenges with deploying bundled IoT services is making them simple to install and maintain. Complicated systems lead to longer time spent on the job site, frustration, and lost profits. Companies need to keep their products simple so that IoT doesn’t get in the way of traditional jobs. Technology should make the lives of contractors and installers easier.

DiLouie: The smart/IoT-enabled lighting bundle may serve two markets—core benefits serving traditional buyers and value-added services serving new buyers. Will electrical distributors be able to serve both of these markets?

Ryan: I think the real question for distribution is where the intersection is between IoT service sales and the tradition lighting sale. At one level, distribution will sell higher-end systems, and will see benefits there. There are also some lighting-channel specific IoT services – things like preventative maintenance, and lighting-asset management, that will unlock new opportunities for selling to the traditional buyer. But I think it’s still very much an open question of how value-added IoT services will actually be sold, and what role the traditional channel will play there. The majority of the new services being developed are really orthogonal to what distributors do today. Regardless of how it all plays out, I expect traditional distribution to play a huge role.

DiLouie: You stated that the buyer of lighting is not the user of the bundle’s value-added services, which is a key difference with consumer electronics. What does this mean? How does it affect the lighting market?

Ryan: The reason bundle economics are so powerful is that it reduces the price of obtaining a suite of products for the end-user. Instead of buying a music player, a telephone, a calculator, and a mobile TV separately, I can just buy an iPhone. That model works because the person making the purchasing decision (me) is also benefiting from all of the services. And since the utility of the bundled product is so high, the seller of the product (Apple) gets to serve a much larger market.

Lighting is different in that the buyer of lighting – typically someone in facilities – is not the user of, and does not benefit from, IoT services. If a facilities manager invests in deploying IoT technology from their own budget, another department will get the benefits. This would be like someone like myself spending $900 on an iPhone and only using it to do phone calls, but then handing the rest of the phone over to my cousin to watch YouTube videos, surf the web, and post on Facebook.

DiLouie: What potential roles will electrical contractors serve in the future lighting market? What are potential scenarios where contractors are winners or losers? How can they position themselves best to survive, and thrive, during disruption and bundling in lighting?

Ryan: I don’t think contractors need to – nor should we expect them to – become experts in IoT services to still play the important role they play in the channel today. Intelligent lighting systems need to be simple to install, commission ,and maintain. If deploying a lighting-based IoT network becomes as costly as maintaining an independent network, then why bundle at all?

The one wild-card in the market is low-voltage DC lighting controls solutions like PoE, which is gaining momentum in the new-construction segment and allow contactors to tap into a different pool of labor for executing projects.

DiLouie: What potential roles will electrical distributors serve in the future lighting market? What are potential scenarios where distributors are winners or losers? How can they position themselves best to survive, and thrive, during disruption and bundling in lighting?

Ryan: As anyone who’s ever looked at the value-chain for lighting & constructions projects will tell you – it’s a complicated channel. And most of the “disruptive” products that people talk about aren’t going to change the buying process for your typical project. So I think that for the foreseeable future, distribution’s role will remain largely the same. There will be more opportunities to sell higher-value products, and for those distributors who strive to move up the value-chain, opportunities to develop deeper end-user relationships. I think the broader point here is that by moving into an entry-point for IoT, the total available market opportunity for the entire industry is going to increase – which will benefit multiple players in the channel.

DiLouie: If you could tell the entire electrical industry just one thing about disruption posed by LED/IoT, what would it be?

Ryan: Channel & access to market – not technology – continue to remain the most important drivers of activity in the lighting space. I don’t think we’ll see true “disruption” – in the classic sense of the word – until we see changes in how lighting projects are specified & sold. That is certainly going to evolve as IoT capability starts to make its way into more project specifications, but I tend to think the disruption story gets a little overhyped.

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Cree Canada’s Shirley Coyle’s Response to AMA Outdoor Lighting Guidelines

Shirley Coyle, President of Cree Canada, recently contributed her thoughts to Lighting Design & Application in response to a request to chime in on the American Medical Association’s recent guidelines…

Shirley Coyle, President of Cree Canada, recently contributed her thoughts to Lighting Design & Application in response to a request to chime in on the American Medical Association’s recent guidelines for LED outdoor lighting.

She points out that basing recommendations on correlated color temperature (CCT) is flawed:

On the issue of safety, the most obvious flaw of the concerns raised is that CCT is not the issue at all — CCT is an overly simplistic value that describes the colour appearance of a light source, and for these issues the important metric to consider is the specific blue content, and more specifically the melanopic response, which cannot be captured in CCT. And along with spectral content, consideration has to be given to dosage, duration, and time of day.

She points out that the leading health issue is driver and pedestrian safety:

So there is a disconnect here between real lighting science and those leading the outcry on the basis of CCT. Fifty percent of fatal collisions happen at night time even though only 25% of roadway travel happens at night time. There is a statistics-based consensus that roadway lighting decreases night time collision rates. We light roadways primarily for safety reasons: the goal is to use well-designed roadway lighting to improve visibility for drivers, including their ability to detect other vehicles, pedestrians and cyclists.

Check it out here.

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2017 DOE SSL R&D Workshop Presentations Posted

Earlier this year, the Department of Energy hosted its 14th annual Solid-State Lighting R&D Workshop. Over three full days, 250 attendees participated in sessions covering LED and OLED technology. Presentations…

Earlier this year, the Department of Energy hosted its 14th annual Solid-State Lighting R&D Workshop. Over three full days, 250 attendees participated in sessions covering LED and OLED technology. Presentations from 60 experts addressed the complex science and technology challenges facing SSL today, as well as innovative new ways to improve manufacturing processes, reduce costs and foster U.S. competitiveness.

Check out the presentations here.

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DOE Publishes Report on LED Street Lighting’s Impact on Sky Glow

DOE has published the results of a study of the expected contributions to sky glow from converting high-pressure sodium (HPS) street lighting to broader-spectrum (i.e., white light) sources, with specific…

DOE has published the results of a study of the expected contributions to sky glow from converting high-pressure sodium (HPS) street lighting to broader-spectrum (i.e., white light) sources, with specific focus on LEDs, and presents the contributions in a manner relative to HPS baseline conditions. These conditions represent typical conversions in the U.S. and include changes in spectral power distribution (SPD), percent uplight, and lumen output.

Among the findings of An Investigation of LED Street Lighting’s Impact on Sky Glow:

• All of the LED product conversions reduce sky glow relative to an HPS baseline when the results are expressed as unweighted radiant power, for both near and distant observers.
• When the results are scotopically weighted to evaluate the effects on human vision, some LED products reduce sky glow for the near observer compared to the baseline, and others increase it, depending on their relative content of shorter wavelengths. An important related finding, however, is that CCT is not a very reliable predictor of sky glow impacts, especially when scotopic weighting is not applied.
• Overall, the results for LED conversions in this study ranged from a low of 0.2 to a high of 1.6 times the baseline HPS sky glow, depending on the combination of variables and factors studied.
• For a distant observer under the scenarios modeled, even at only 40 kilometers from the city center, the elimination of uplight that occurs in typical conversions nearly removed (by 95% or more) the contribution to sky glow from the street lighting system, for both the unweighted and scotopically weighted results, for all SPDs and atmospheric conditions.

Click here to get the report.

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