Getting the innovation right: the need for evaluation, measurement & validation of LED lighting (MAGAZINE)

Bringing products to market based on new technology is a risky business. The small number of truly successful innovations contrasts with the large number of new products that have failed to realize their promise. It can be confusing to read about how advancements in LED technology are transforming the lighting industry, because that future won’t happen unless we get the innovation right. We should consider how solid-state lighting (SSL) technology companies can employ system engineering, with all critical stakeholders using better measurement, validation and communication to get the innovation right in today’s new economy.

To efficiently penetrate the market and realize its full potential, key stakeholders must play their part in building a comprehensive and accurate body of knowledge about the new product experience. This will assist the earliest customers in making informed, thoughtful and prudent decisions, and help build the market on a foundation of realized expectations.

Such a body of knowledge includes two important components. First is the technical performance of the product in real-world conditions. This includes all aspects of the whole-product performance (including the LED chips and their drivers), and encompasses energy savings and power quality; product life and maintenance; light output, color, temperature, and uniformity; dimmability and controls performance; and environmental impacts.

Second is the user benefits and real-world impact of the product. In the case of SSL, some possible impacts include:
• The relative value of an entirely-new customer experience. This can only be understood through gauging consumer reaction to the in-situ experience of an activity under the new lighting conditions.
• The enhanced brand of a retail business and its attractiveness to customers, as well as enhanced real-estate value.
• Monetizing the value of improved productivity and health of employees, or of livestock in agricultural environments.
• Increased safety and security of business and municipal environments.

LED lighting represents perhaps a true opportunity for a potential technology home-run. In the March 2011 issue of LEDs Magazine, Philip Keebler of the Electric Power Research Institute (EPRI) demanded “show me the data” and pointed out the need for more measurement and validation of system efficacy, driver efficiency, and power quality. We agree, and call for even further data analysis that is focused on the customer.

FIG. 1.

Today’s customers increasingly rely on the internet, social media and customer testimonials to learn about new products. Word of the initial product experiences of early adopters are likely to spread quicker and further, and therefore are more influential in driving future market decisions. If product performance claims are not backed up with solid field data, mainstream adopters will be more skeptical, affecting market share. Those LED manufacturers that listen to customers and deliver and report authentic new value will be the successful ones.

Manufacturers as stakeholders

The market for new lighting products is competitive, and the potential rewards are high. Manufacturers must trade off the desire to be first to market with the need to provide the market with robust information about product capabilities and performance. Successful products will be focused on meeting stated and unstated customer needs. New-product-development guru Robert Cooper says the inability to effectively match a new product to real-world customer needs is the most frequent reason for new product failures in America.

Getting truthful answers to the good, bad and sometimes painful side of LED lighting is critical to ultimate market success. Among the key questions are:

• What drives a consumer to pay (or not pay) for energy efficiency?
• What level of dimming provides energy savings without sacrificing perceptions of safety in outdoor lighting?
• What are the primary components of value, and what are they worth?
• Alternatively, what are the pain points with today’s lighting that will drive consumers to LEDs?

For companies intending to be in the market for the long haul, it makes good business sense to be a leader by providing decision makers with a robust body of knowledge regarding new products. Measurement and validation should include:

• Relevant customer research data
• Test data for standards and certification compliance
• Independently-verified field-performance data
• Case studies to illustrate the application and customer reaction.

Demonstrations

Outsourced Innovation has managed over 15 LED demonstrations in collaboration with Midwest utilities, ranging from outdoor street and area lighting, to on-campus university lighting, to creating LED lighting conversions in agricultural settings. Among the lessons learned from these demonstrations is that measurement and validation clarifies product performance and aligns expectations with proven performance. Also, business value beyond energy savings is just as important and needs to be evaluated, too.

A true breakthrough will not occur just because LED technology is used, but because of the added value the technology brings to enrich our lives. We need to understand and monetize that added value.

The DOE works hard to publish realistic reports from both Gateway and Caliper programs. These studies help temper the “coolness” factor surrounding the notion of digital lighting, so the marketplace won’t be disappointed with LEDs.

If there is an unforeseen problem or disappointment with SSL, the product can leave a bad impression with the public. Even if a fix is found that makes the product superior to anything else in the marketplace, the damage can be irreversible and be further exacerbated with today’s social-media tools. So understanding your customer and the complex operation of SSL systems is advisable before making one big enthusiastic sales pitch on LEDs.

Municipal and commercial customers

The City of Apple Valley, MN, and its host utility Dakota Electric Association surveyed residents as part of a recent demonstration project. Brightness was found to be the most important characteristic in a residential street-lighting system. Surprisingly, energy savings, light trespass and color were far less important to consumers (Fig. 1). These results suggest that, when residents view brightness as far more important than energy savings, education is needed to support the rationale for reducing light levels during after-midnight hours.

The good news is that our research consistently shows that, no matter what the geographic location, LED outdoor lighting is preferred to conventional street lighting by a factor greater than 7. But a related question for builders and home buyers is this: will an LED lighting system create a more attractive place to live, adding new value to real estate? New product research should characterize that value, as it will help justify a scalable deployment of new and more expensive technology.

FIG. 2.

Another promising example includes the city of Bettendorf, Iowa, which is collaborating with its host utility, MidAmercian Energy, to better understand the performance of LED lighting in front of the downtown Quad Cities Waterfront Convention Center (Fig. 2).

After testing several manufacturer’s products, the city chose thirty-two Capella LED fixtures from Philips. The lamps were installed on State Street and promise to deliver a 45% energy saving. The city of Bettendorf routinely tracks residents’ perception of downtown safety at night (Fig. 3). Results show a 20% increase in the city’s safety score at night following the installation of LED streetlights in 2009. Defining additional value of this type will be important in order to accelerate the technology adoption with other municipalities.

Taking it one step further, the city of Bettendorf could track whether the downtown convention center attracts more visitors or lures more booked conventions due to the installation of SSL systems. Again, this level of evaluation could help to justify such installations.

FIG. 3.

Business tactics such as these are referred to as Blue Ocean strategies, where value innovation becomes so important that competition is irrelevant and price becomes inconsequential. This is a good market strategy for SSL as long as we understand it and leverage the technology to create meaningful value that goes well beyond energy savings.

There is a growing body of evidence that customers are installing LED lighting products like light bulbs, with very little if any efforts to understand the nuances of the semiconductor technology or consideration of whether it indeed makes a good business case. But doing business without listening to the customer is like sailing a ship without a rudder: it may take a lot longer, or worse yet we may never get there.

Lighting professionals may not always understand the unique photometric characteristics of LEDs, or their optical or thermal behavior. They may not have regard for what type of LED lighting system the community prefers on the parkway in front of their homes, or whether residents may want to have less-bright streetlights or even the ability to control brightness. New innovation cannot survive on intuition alone.

These communities can be our labs. A close watch of customer insights can bring innovation to the most iconic and established products like lighting. But a lack of coordination and good data collaboration has been a big barrier to innovation in the past.

Examples from agriculture

Another critical example involves US-based agricultural businesses. What problems have evolved in such operations using today’s energy-efficient lighting systems, and what new value can be engineered into an LED system?

The National Rural Electricity Cooperative Association’s (NRECA) Cooperative Research Network, along with Oklahoma State University, has commissioned several agricultural LED field assessments to seek some answers. Early power-quality measurements suggest LED performance that is true to manufacturers’ claims, and that has matched or slightly better light levels (Table 1 and Table 2) compared with incumbent technologies. Energy savings of 50% have been validated for LED conversions in both swine and dairy facilities.

TABLE 1.

These results are laudable, especially as the measured LED lights at both agricultural test sites put out the same amount of illumination as the legacy lighting systems they’ve replaced.

For these field studies, researchers hope to prove that the added value goes beyond energy savings. The hypothesis is that animal livestock and poultry will exhibit measureable weight gain or increased milk production, or that farmers could realize a reduction in feed costs by leveraging the spectral light intensity of LEDs. Many of today’s progressive farmers have advanced tracking systems in place to evaluate behavioral data, along with the power-usage data collected by the utility, so the full value of the new lighting system can be determined.

TABLE 2.

Rich Robinson of Robinson Family Farms, who owns and manages a swine operation with 22,000 sows in Holdenville, OK, reported: “As you can imagine, our operation is harsh and dirty. The energy saving from the LED prototype lamps in our swine facility is proven, but now we can hose and foam-clean the lamps without fear of breakage, which is a common occurrence with CFLs.”

Robinson further commented: “We’ve gone through 3 cycles of piglets with no damage or breakage to the LED lights and that’s substantial when we typically replace many CFLs each month. That’s the real value of LEDs for our operations.”

Table 2 shows promising results from an LED dairy conversion project for about 120 milk-producing cows. However, these findings beg the question: will more LED fixtures be required or could re-engineered optics provide the additional benefit of driving a behavioral change? And especially as past research implies that 15 foot-candles are necessary to instigate an increase in milk production (Josefsson et al., 2000). The answer appears to be no, more LED fixtures may not be required: early field data at the dairy is showing a 13% increase in milk yield on the LED side of the barn, suggesting a compelling argument for LEDs. However, there is a need for continued study.

Utilities as stakeholders

Electric utilities have an important role in demonstrating significant new energy-saving products and in facilitating their adoption in applications that make good business sense. CFLs have been a pillar of utility energy-efficiency program portfolios, but now utilities are beginning to embrace SSL.

Utilities and their regulators are recognizing the importance of a comprehensive measurement and verification approach to validate the full value of SSL and ensure an apples-to-apples baseline comparison for determining energy-efficiency savings.

Outsourced Innovation recently held a workshop for MidAmerican Energy on solid-state street lighting, bringing together Iowa municipalities, manufacturers and distributors. The main take-away from the workshop was how utilities and municipalities typically don’t have the staff to select a quality LED system. Dave Ahlberg, MidAmerican Energy’s Product Manager of Industrial Energy Efficiency Programs, stated: “We want to be a good resource for our customers and advisor for SSL projects, offering grants or incentives to help prove market acceptance of the technology.”

For SSL, utilities will also need to be creative in designing new rate structures that preserve the diversity of street-lighting ownership options now offered to municipalities. Utilities like the controllability features of SSL, which allow lighting-optimization strategies for different municipal applications and have a natural fit into the industry’s vision of the “smart grid.”

Utilities strive to achieve reliable electricity service and high customer-satisfaction scores. Consumers look to their electricity provider for leadership and education on emerging technologies that save energy. Good measurement and validation provides customers with the unbiased facts on the results that new technology can deliver.

Conclusion

SSL has significant market potential, but it is still in the critical early stages of its development. Product success depends upon the market taking a system-engineering approach and evaluating the individual technology components as an integrated product that provides a variety of customers with an important and complex energy service. Market participants must also support customer decisions by tempering product claims with solid real-world test results, as well as designing products and services that provide optimal value by listening to the customer.

Manufacturers, service providers, municipalities, electric utilities and end users all have a stake in the success of SSL technology. Getting the innovation right is more important today when word of failed expectations can reach so many decision-makers very rapidly. However, we can indeed leverage SSL’s future market potential to transform lives and position the economy to move forward.

About the Author

Nora Lighting Releases Handy “Pocket Guide” Featuring More Than 500 New Products

Mechanical Electrical Electronic Technology, Canada (02-May-2012 to 03-May-2012)

Elemental LED Announces Lower Prices on Popular Replacement LED Light Bulbs

The LED lighting retailer cuts prices on three screw-in LED light bulbs by up to 45%, signaling a similar trend throughout the industry.

Elemental LED, a San Francisco Bay Area-based LED lighting company, recently cut prices on its popular Tess Bulbs, the LED Replacement Bulbs with a standard e26/27 screw-in base and cutting-edge Cree LED chips. 6W Tess Bulbs, a replacement for standard incandescent 30W bulbs, were $29.99 and are now $17.99. 7W Tess Bulbs, equivalent to 40W incandescent bulbs, were $34.99 and are now $19.99. 9W Tess Bulbs, a 60W replacement, were $39.99 and are now $21.99.

Elemental LED introduced the Tess Bulb to its catalog last year as a top-of-the-line product with significant improvements in function and light quality to that of its LED replacement light bulb predecessors. Tess Bulbs are UL listed and feature Cree LED chips, top-rated for their brightness and energy-efficiency. According to Cree, “Cree LEDs combine highly efficient InGaN Indium gallium nitride materials with proprietary G•SIC® substrates to deliver superior price/performance for high-intensity LEDs.”

The prices of LED light bulbs and fixtures are decreasing dramatically throughout the industry, making them an economically viable option for consumers. The price decrease follows similar trends of other consumer electronic products, for which a gradual increase in demand and consumption leads to a dramatic lowering of prices.

Features of the Tess LED Light Bulb include no flickering or humming, a durable housing that is difficult to break, no warm-up time required, and no mercury. Containment of toxic mercury, flickering, humming, fragility and slow warm-up are all well documented problems with CFLs. The Tess Bulb lasts for 50,000 hours, 10 to 50 times longer than a standard incandescent bulb or CFL, and uses 20% as much energy as an incandescent bulb.

The Tess Bulb is available in a warm white color temperature, which creates an inviting, smooth, even light for indoor living spaces. It is also available in neutral white, which works well against metal and cool color tones or outdoors.

The decrease in prices by Elemental LED signals that the company is positioning itself as a viable competitor to big box retailers. “We are top of the market when it comes to quality and customer service,” says Director of Business Development Matthew John, “In the past some of our competitors have beat us in terms of price, but that is quickly changing.”

ANSI evaluates revisions to SSL chromaticity standard (MAGAZINE)

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This article was published in the July/August 2011 issue of LEDs Magazine.

View the Table of Contents and download the PDF file of the complete July/August 2011 issue.

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In early 2008, the American National Standards Institute (ANSI) published its Solid State Lighting (SSL) color standard, ANSI C78.377-2008, entitled “Specifications for the Chromaticity of Solid State Lighting Products.” For manufacturers, this standard defines how to communicate the chromaticity of white-light SSL products to end users.

After two years of practice using this LED standard, the industry recognized the need for improvements in its accuracy and the need to make the standard more user-friendly. In fall 2010, the ANSI Technical Committee TC78, Working Group of SSL Light Source WG09, formed an ad hoc task force to define the appropriate revisions to the document, focusing primarily on making improvements without requiring major thematic changes.

Similar to other lamp-color standards, this specification will provide recommendations on the white-color-variation ranges when SSL products are used for indoor lighting applications. The white-light chromaticity specified in the standard may deviate from “perceived” white, but are generally acceptable to most users.

Variations of white

The variations of white are primarily described in four so-called directions. These are yellowish (or warm) white; blueish (or cool) white; greenish white, and pinkish white. The variation from yellowish to blueish white occurs in the direction of the correlated color temperature (CCT), where the CCT ranges from lower temperatures (warm white) to higher temperatures (cool white), and the change is measured in delta T. Meanwhile, the variation from greenish to pinkish occurs as a deviation from the Plankian locus or blackbody curve, and is measured in delta uv (Duv). The Duv value on the curve equals zero, while the direction towards greenish color has a positive Duv, and conversely the direction toward pinkish color has a negative Duv value.

The CCT range and Duv range together form white-color boundaries that are detailed in the ANSI SSL chromaticity standard. Using this specification, a manufacturer of SSL products and the users of these products can achieve a common understanding of how any given white color will appear on the chromaticity diagram where the color point of the product fits within (or outside of) these color boundaries.

The ANSI standard does not imply that the whites that fit within the color boundaries are the “good” whites, or that those outside of the color boundaries are inferior. This is because the perceived whiteness of a light source is not directly related to its color rendering capabilities, or to personal preferences. Interestingly, if products’ color variations or tolerance fall within these ranges, they will not necessarily be consistent for observers. In other words, the specified color tolerance in the ANSI standard is large enough that color inconsistency from the same CCT products can be detected.

About the Author

LED lighting and control systems evolve for optimal efficacy (MAGAZINE)

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This article was published in the July/August 2011 issue of LEDs Magazine.

View the Table of Contents and download the PDF file of the complete July/August 2011 issue.

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For multiple fiscal and environmental reasons, lighting efficacy – defined loosely as light only when, where, and how it is needed – should be given the utmost consideration when we deploy lighting systems. From an energy-consumption standpoint, LED-based lighting represents the most important advancement in lighting in decades. LEDs as light sources are inherently efficient and LEDs can be configured in systems that are much more intelligent in terms of both controllability and adaptability than traditional fluorescent and HID technologies. Indeed LED-based solid-state lighting (SSL) can provide an advantage in efficacy from many angles, but luminaire and control-system architectures must evolve to deliver truly optimal efficacy.

From a system perspective, lighting efficacy is comprised of several elements, all of which are of first-order importance. Several are outlined in Table 1. Light source efficacy is not enough. Truly efficient lighting also requires efficient electronics, fixtures that don’t waste light, and control systems that further reduce wasted light.

Table 1. Elements of lighting efficacy

Based on efficacy advantages, LED-based fixtures appear to be either in the lead or quickly approaching the lead in many applications such as high-bay lighting, street lighting, indoor downlighting and even fluorescent troffer replacement. Still, we need to rethink proper light levels, focus on lighting only where it is required, and push deployment of control schemes to maximize energy savings and eliminate light pollution in the environment.

The lighting industry still has work to do in determining proper light levels. For example, regulatory bodies in North America do not currently take into consideration the differences between photopic (day), mesopic (dusk), and scotopic (night) human visual systems. Our visual system has evolved to account for the differences in lighting between day and night. During bright sunlit days, our eyes are more excited by warmer CCTs (correlated color temperatures) than during dim nights when our eye sensitivity shifts toward the colder, more-bluish moonlight. Mesopic lumen output describes a situation in between photopic and scotopic and is generally considered the most appropriate measure for street lighting.

Efficacy and eye sensitivity

The differences in efficacy can be dramatic when considered relative to photopic, mesopic, and scotopic sensitivity. This is shown in Table 2, which compares a low-CCT high-pressure-sodium (HPS) source to a much-higher -CCT, metal-halide (MH) source. High-CCT sources such as MH and LED are not necessarily given proper credit for exciting the eye in an optimal way for given environmental conditions. Given the data in the table, it’s no surprise that many people involved with case studies report that LED street lights with a lower total lumen output appear brighter than higher-total-lumen HPS street lights. Note that this statement refers to the brightness of the target area and not the fixture itself which may (falsely) appear brighter due to glare effects. We need standards that ensure safety without wasting light and energy.

Table 2. Comparison of high-pressure sodium (HPS) and metal-halide (MH) source efficacies.

Likewise, some regulations and guidelines don’t consider the CRI (color rendering index) of a light source even though it has recently been proven to have an effect in some applications (again, like street lighting) where small-target visibility is critical. Both CCT and CRI are critical because the required lumen output of a lamp varies greatly based on these factors. That said, their importance is still being debated and as recently as 2007, CIE’s stated position in CIE 180:2007 is that, “Colour rendering is not highly important for roadway lighting, except in sensitive urban centres and/or areas with large numbers of pedestrians.”

Utilization factor

Now let’s discuss utilization factor. The first three efficacy elements in Table 1 are static, at least within a relatively short timeframe of days or weeks. This is not the case with the fourth element that addresses the difference between the light supplied relative to the light needed. Utilization factor is a combination of the percentage of time that the lights are on and, when lights are on, the intensity of the light compared to what’s required or being utilized. Optimized lighting controls are essential to improving utilization factor and thereby reducing energy costs. LED lights present a new opportunity for controls as they are easy to regulate using various dimming methods, sensor interfaces, and communication infrastructures that allow the light to be modulated based on environmental conditions.

Lighting systems can perform occupancy detection to control on and off states. Several technologies can detect occupancy including passive infrared (PIR) or ultrasonic motion sensors, capacitive- or MEMS-based microphones, and digital cameras that perform image processing. Motion sensors are relatively inexpensive and are used most often although a combination of a motion sensor and another occupancy-detection method can yield superior performance. Multi-technology sensors decrease the likelihood of erroneous behavior, thus maximizing precision and decreasing energy usage.

Controlling fixtures and dimming lights to produce the appropriate amount of artificial light based on ambient light conditions is critical to both energy efficiency and user experience. Dual-loop sensors are now able to differentiate between light provided by the sun and artificial lighting systems so that fixtures can maintain a consistent light level on a target area. LED-based lamps have the advantage that deep dimming is easy to do and actually increases lamp life, in contrast with competing technologies.

Leveraging lumen depreciation

SSL also affords the potential of further energy savings in luminaire designs that accurately account for lumen depreciation in regulating light output. Light-output regulation is very important to LED-based lighting because of the technology’s extremely long lifetime. If properly protected and driven, LEDs shouldn’t burn out. Instead, the LED light output decreases over time based on a phenomenon called lumen depreciation. L70 is a parameter that describes the point in time at which the light output has decreased 30% from its initial value, and is typically on the order of 35,000 to 100,000 hours for LED lamps, as shown in Fig. 1.

FIG. 1.

To maintain a minimum amount of light output over the lifetime of a fixture, say 750 lm for a 65W replacement lamp or 6,000 lm for a parking-lot light, many fixture designs initially output 30% more light than is required. This represents a significant waste of electricity in that the target area is being over-lit for virtually the entire lifetime of the fixture.

Intelligent fixtures can regulate the light output to a lower level initially and increase the output over the fixture life. Ancillary benefits include consistency of light intensity and color, lower overall energy expenditure, and lower total thermal load. Lowering the total thermal load is extremely beneficial as it leads to longer lifetimes for all electronic components, especially the LEDs and power electronics.

Though beneficial, light-output regulation provides a significant technical challenge. One could use a predictive algorithm that estimates LED efficacy or output based on hours of operation and temperature measurements. But LED performance over time and temperature may not be all that predictable. For several families of LEDs from various suppliers, the actual lumen-depreciation curves have been shown to be significantly shallower than those predicated by accelerated, high-temperature testing.

Alternatively, a fixture design could add a sensor to measure the lumen output during operation, but there are challenges here as well. First, achieving proper mechanical placement of the sensor to measure overall- or average-lumen output may be difficult or even impossible. Second, dirt can can prevent photons from getting out of the fixture and may even redirect them towards the sensor, thus corrupting the measurement. Third, sensor aging and temperature drift could complicate matters even further.

FIG. 2.

In lighting systems, external sensors could measure the light output and communicate the data to the fixture. Such a system could be cumbersome, costly, and have its own set of technical issues. The right answer is likely a combination of approaches, and light-output regulation appears to be one area that is ripe for innovation.

Microcontrollers and networks

Clearly the industry must move toward intelligent lighting platforms to maximize energy savings via sensors, programmatic controls, and communications links between fixtures. Such intelligent luminaires rely on driver modules that integrate a microcontroller for interfacing to sensors and for control of the dimming profile. The smart fixtures enable managed-lighting systems with wired- or wireless-communications capabilities.

The communications infrastructure allows lights to communicate with each other, with remote sensors, and with centralized control and data-collection points. Such control systems have existed for some time but have not been widely deployed, having an estimated market share at 2% to 4%. Cost and complexity have hampered deployments. Moreover, the lighting industry focused first on more efficient sources such as fluorescent and HID that weren’t inherently controllable.

With LED sources, it’s time for broader deployment of control networks although the technology landscape is fragmented. Wired communications options include 0-10V dimming, DALI (Digital Addressable Lighting Interface), DMX (Digital Multiplex) or power-line communications. Wireless personal area network (PAN) options include Zigbee, Z-Wave, 6LoWPAN, or even Google’s new Android lighting platform. All may find usage although the market will likely pick the winners.

New lighting system topology

The trend is clearly toward systems that integrate the control strategies and intelligence directly into the ballast or driver. But, the overall power-supply and control architectures of these systems will likely change to take full advantage of LED technology. For example, consider a space lit by four 25W downlights, as shown in Fig. 2.

The lamps are controlled by remote occupancy and ambient-light sensors over a wireless PAN. A wired configuration could just as easily have been shown. Regardless, each fixture operates from line voltage and includes significant intelligence and therefore requires:

• 25W AC/DC converter
• 25W DC/LED constant-current converter
• Radio for the wireless PAN
• A relatively expensive microcontroller including flash memory for the PAN protocol stack
• Energy meter
• Optional sensors (temperature, light output, or color).

FIG. 3.

As shown in Fig. 2, data gathered by the MCU could be backhauled to a central location that records energy usage. Such a system could also be under remote control in addition to being able to interface to local sensors. This system, while perfectly functional, is expensive to implement and does not take into account the simple but significant fact that we now have a light source that is easy to power remotely. An alternative approach is shown in Fig. 3.

In this case, the 100W power supply incorporates the room controller/coordinator and is therefore capable of communicating directly with the sensors and the remote-control/data-backhaul interface. In this case, each fixture contains:

• 25W DC/LED constant-current converter
• A relatively inexpensive microcontroller
• Optional sensors (temperature, light output, or color).

From a power-supply standpoint, one 100W AC/DC converter is both more electrically efficient and less expensive than four 25W AC/DC converters. Energy metering is performed at the centralized power supply instead of at each lamp. The lamps communicate with the 100W supply over an extremely simple and inexpensive wired interface and therefore contain a less-expensive microcontroller, lighter communications-protocol stack, and no radio. Finally, if the optional local sensors aren’t needed, then no electronics are required locally inside the lamp – the 100W power supply could send a constant current directly to the lamp.

Our proposed system lies somewhere in the spectrum between 100% local power supplies and intelligence and 100% remote power supplies and intelligence (something akin to Redwood Systems’ technology). The market must decide on the best solution.

Finally, artificial-intelligence or fuzzy-logic technology will enable these systems to become more efficient by enabling active learning – prediction of occupancy and even a user’s desired light level. Such systems could also greatly simplify and possibly even eliminate the commissioning process. This is obviously yet another area begging for innovative solutions.
About the Author

LFI report, part 1: Linear LED lighting, OLED and planar lighting (MAGAZINE)

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This article was published in the July/August 2011 issue of LEDs Magazine.

View the Table of Contents and download the PDF file of the complete July/August 2011 issue.

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LFI report, part 2: Retrofit lamps, modular SSL

LFI report, part 3: LED technology, outdoor lighting

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LEDs again stole the show at the annual Lightfair International (LFI) tradeshow. While you could find plenty of conventional lighting on the exhibit floor, it was solid-state lighting (SSL) products that were prominent in most booths, ranging from A-lamp retrofits to decorative and architectural lighting. Purpose-built LED-based linear lighting that might replace fluorescent fixtures was arguably the biggest story. There was little new on the OLED lighting front at LFI, but other planar technologies are coming to market. There were both new players and new looks in outdoor SSL. And adaptive-control technology for sensing and controlling light levels is headed into the mainstream – despite the lack of broadly-accepted industry standards.

LFI continues to surge in popularity and surely LED lighting is partially responsible. Despite some concern in the industry about moving LFI to Philadelphia due to construction issues at the New York venue, registered attendance hit 23,709 – up slightly from last year’s Las Vegas show.

Again this year SSL dominated the LFI Innovation Awards. The Most Innovative Product of the Year award went to the Revel OLED luminaire from Acuity Brands. The Design Excellence Award went to Tech-Generation Brands for a low-voltage LED-based wall washer. Philips Lumileds took the Technical Innovation Award for its Luxeon A LED that the company is hot-testing at typical operating temperatures of 85°C. LED-based products also dominated the product-category awards, with winners including Cooper Lighting, Visa Lighting, and Lumenpulse.

Ironically, LEDs were an afterthought in the keynote presentations this year. But the conference sessions included plenty of LED-centric content.

In the following pages, we’ll present what we saw as the most-compelling product announcements and demonstrations in OLED and planar lighting, linear LED lighting, LED retrofit lamps, modular SSL products, LED technology, outdoor lighting, and other areas.

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Section 1: Linear LED lighting

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At LFI a year ago, LED-based lamps designed to replace T8 linear fluorescent tubes were in the headlines as many companies sought to deliver an SSL retrofit for what is the largest installed base of office and industrial lighting. But as we reported after the show, LED tubes haven’t delivered equitable performance.

This year the focus was more on purpose-designed LED-based fixtures that can serve in place of fluorescent troffers. That’s not to say there weren’t LED tubes on display. In fact, Cree showed a T8 tube reference design that product marketing manager Paul Scheidt said “addresses all of the shortcomings that the US Department of Energy (DOE) has documented about LED T8s.” Still, the bigger fluorescent-replacement news in the Cree booth was the CR fixture that the company launched prior to the show.

RTLED from Lithonia Lighting

Lithonia Lighting (an Acuity Brand) was out in front of the purpose-built, LED, linear-fixture trend by announcing the RTLED product at LFI last year, and showcasing the family in its 2011 LFI exhibit.

The product also integrates support for Acuity’s lighting-control technology that relies on wired links between fixtures using Cat-5 (computer-network) cables. Moreover the products implement what the company calls lumen management where the LED driver produces less output early in the fixture life and increases the output over time to combat lumen depreciation.

Lithonia also demonstrated square surface fixtures called TLED, and square recessed ACLED coffer fixtures, both of which use an array of LEDs and feature integrated controls.

LED Distributed Array from Osram

Osram Sylvania introduced an LED module for linear fixtures that it will both sell to others and use in its own luminaires. The LED Distributed Array integrates 48 LEDs on a 2×9-in circuit board. Luminaire designers can utilize multiple modules to create fixtures of almost any size. The company states that the module design produces uniform diffused light with no apparent bright or dark areas associated with LED location.

Just after LFI, Sylvania’s sister business unit Osram Opto Semiconductors announced the Duris E3 LED designed with a wide beam angle to produce uniform light in linear fixtures.

ALM LED module from Cooper

Cooper Lighting launched an LED module called the ALM that the company will use as a technology base for linear lighting, and also unveiled 32 luminaires across Cooper brands that will utilize the new module.

The module design is based on a dense array of relatively low-power (0.25W) LEDs, and the design only drives the LEDs at half the rated power. The scheme optimizes efficacy, according to Cooper, and will yield products that last 50,000 hours. The company asserts that its linear products will match or exceed fluorescent systems in optical performance with a 15-20% reduction in power density.

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Section 2: OLED and planar lighting

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Acuity Brands took the top LFI Innovation Award with its Revel OLED luminaire, and actually announced two OLED products at LFI. The ceiling-mounted Revel (pictured) is more decorative in nature although the individual OLED modules can be positioned to direct light where it is needed. The Kindred is a stylish ambient light designed to be suspended from the ceiling. The Kindred integrates more OLED panels and produces more than 3000 lm in aggregate. Acuity termed the LFI announcement a commercial launch, but the products will not be available until the first quarter of 2012.

Oree’s LightCell planar LED-based technology

Oree and Future Lighting Solutions have partnered hoping to commercialize Oree’s LightCell planar LED-based technology. At LFI, the partners conducted private demonstrations of tunable white panels whereas much of Oree’s earlier efforts have been focused on color panels.

As shown in the picture, the panels are relatively small, but Oree believes they can be combined to construct much larger fixtures. Each small panel includes built-in LED emitters. Future plans to have a demonstration platform available for sale by the end of the summer, allowing product designers to experiment with the technology and start luminaire designs. Separately, Future announced an intelligent lighting platform based on a partnership with Synapse Wireless.

Rambus from GE Lighting

GE Lighting made LFI news with LED-based planar luminaires based on technology licensed from Rambus. Rambus’s edge-lit Pentelic technology relies on etching a substrate layer to control the ray angle of light to provide uniform distribution over a panel. The company has said that the technology delivers 92-95% optical efficiency. GE demonstrated the Pentelic-based Edge family of luminaires at LFI including a ceiling troffer, a circular suspended pendant and a suspended rectangular luminaire. GE plans to ship the troffer this year and the others in the first half of 2012. All of the products will support adaptive controls and dimming for maximum energy savings.

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