BoletĂn de noticias Led Marzo 2009
Ledding the future
LOS LED EN USA
19 Feb 2009│ LA looking at LED street lights, with help from Clinton Climate Initiative Over a five-year period, the City of Los Angeles' Bureau of Street Lighting will replace 140,000 existing streetlight fixtures in the city with LED units. On February 16, former President Bill Clinton announced that the Outdoor Lighting Program of the Clinton Climate Initiative (CCI) is working with Los Angeles on the largest LED street lighting retrofit project ever undertaken by a city to date, said a report by the CCI. Over a five-year period, the City of Los Angeles' Bureau of Street Lighting will replace 140,000 existing streetlight fixtures in the city with LED units that not only will improve LA's lighting quality and reduce its electricity use, but also will help the city to save money in the process. While typical streetlight lamps will last from four to six years, LED fixtures have a longer life span, estimated from 10 to 12 years. The new, whitelight LED streetlight units are more durable and damage-resistant than other technologies. This not only will reduce the frequency and cost to repair streetlight fixtures, but also will provide LA with considerable savings in labor and material. The improved equipment life also means that fixtures will more reliably light streets and sidewalks for city residents. In addition, LA is committed to using LED fixtures that will ease what is known as sky glow - the artificial illumination of the night sky. "If you have ever been to Death Valley National Park and looked up on a clear night, you would see that the stars seem to be dimmer than they were when I was a child. But they are not getting dimmer, really - the rest of the sky is getting brighter because of all the lights from Los Angeles and Las Vegas and other surrounding cities and communities," President Clinton said. "Now, thanks to the work of Mayor Antonio Villaraigosa, the Los Angeles Bureau of Street Lighting, and my Foundation's Climate Initiative, the stars over Death Valley may again shine more brightly." Once this overhaul is fully complete, LA will save electricity expended on street lighting in the city by a minimum of 40 percent and reduce carbon emissions by approximately 40,500 tons a year,
Clinton and LA Mayor Villaraigosa
which is the equivalent of taking 6,700 passenger vehicles off the road every year. Over a seven-year period, the city will save a total of $48 million and reduce carbon emissions by 197,000 tons. After the loan is repaid in seven years, LA will continue to save $10 million annually as a direct result of this lighting retrofit project. In addition, this loan will have no adverse impact on the city, as the loan payments will be covered in full by savings from current energy and maintenance costs. This LED retrofit project also will include the installation of remote monitoring units at all 140,000 streetlights replaced in the city. These devices will automatically report streetlight failures directly to the Bureau of Street Lighting for immediate repair, thus enabling its staff to optimize its maintenance services. "If every city followed the example of Los Angeles and reduced the electricity used by their streetlights by 50 percent, it would be equivalent to eliminating over 2.5 of those coal plants per year," President Clinton said. "We would do that while saving taxpayers money. And by doing that, we would also reclaim our night sky." CCI's Outdoor Lighting Program works with partner cities to improve the energy efficiency of street and traffic light systems through a combination of technical, purchasing, and project assistance.
19 Feb 2009 │ Pittsburgh and San Jose looking at LEDs for street lighting Two major cities in the USA are considering plans to start converting street lights to LEDs. Pittsburgh is considering the replacement of its 40,000 street lights with LED fixtures, according to a news report in the Pittsburgh Post-Gazette.
The city estimates it could save up to upwards of $1.4 million a year in energy and maintenance costs, and “look nicer.” Next month the city expects to invite firms to submit ideas for a pilot transformation of some portion of the city's street light system to one of several available technologies, including LED, although other efficient technologies have not been ruled out. Public Works Director Guy Costa said the city spends around $4 million a year powering and maintaining its lights, and figured the city could shave $1.4 million from that total.
In this project, LED street lights from four manufacturers installed on four public avenues in the Sunset District of San Francisco, each with a total of five street lights from the beginning to end of the block. On each avenue, 100-watt nominal high-pressure sodium (HPS) luminaires were replaced with new LED luminaires (each street featuring a different LED product). Key findings are: •
Council officials debated how to select a vendor for the work, which could involve a $25 million contract, through a competitive bidding process. • Meanwhile in California, San Jose is looking to replace its 62,000 streetlights with new LED versions that will “cast a white, warm glow, could cut energy costs in half, and will use state-of-theart technology to vary their intensity and timing,” according to the Mercury News. For decades, says the article, San Jose motorists, pedestrians and police have complained about the city's thousands of yellow streetlights, which are too easily confused with traffic signals, and distort the colors of cars and painted curbs. San Jose plans to convert 100 lights this spring, and is seeking $20 million from a government stimulus package to install 20,000 new lights as part of a project that officials think will attract national attention. The goal is to have all the city's streetlights changed by 2022.
2 Feb 2009 │ DOE reports on San Francisco street lighting demo The U.S. Department of Energy (DOE) has published the report from a demonstration of LED street lighting in San Francisco, California. An LED street lighting demonstration in San Francisco is one of a number of DOE Gateway demonstrations that showcase high-performance LED products for general illumination. This Gateway report, prepared by Pacific Gas & Electric and Energy Solutions, provides an overview of project results including lighting performance, cost effectiveness, and potential energy savings.
While lighting performance varied among the LED luminaires assessed in this study, energy savings potential was high in each case, with energy reductions ranging from 50% to 70% over the current HPS system. The products that generally performed better in terms of lighting performance also proved to be more economically attractive.
The report says that, overall, this assessment shows that energy savings potential from current LED street lighting is significant, and that savings potential is likely to further increase in the future as the energy and lighting performance of LED street lights continues to improve. However, not all products currently available are ready for mass deployment; limitations continue to exist in the lighting performance of some. Additionally, economic viability (which is subject to location details), will remain a key factor that must be weighed in concert with lighting performance. Incentive program development may further encourage LED street light adoption. The study recommends that any such incentive programs include performance standards that consider warranty, efficacy, light distribution, and other important criteria.
More cities tap stimulus package for LED streetlights By Judy Keen, USA TODAY Cities across the USA are making their streetlights brighter and greener by switching to LEDs. Light-emitting diodes produce light when exposed to an electrical charge. They cost more than traditional lights, but last longer because they don’t have filaments and use less electricity. Several cities, including Ann Arbor, Mich., and Anchorage, have installed LED streetlights, and dozens more are planning conversions. At least 30 cities have asked for more than $104 million in federal stimulus funds to help them make the change. Pittsburgh’s City Council votes Wednesday on a bid deadline for test LEDs for its five-year, $25 million plan to replace 40,000 streetlights. Councilman William Peduto, a Democrat, says the city could cut its $4 million annual tab for power and repairs. “Our goal is to become one of the leaders in a full transformation to LED technology,” he says. FIND MORE STORIES IN: Texas | Arizona | Illinois | Michigan | Wisconsin | San Jose | Anchorage | Ann Arbor | Racine | LEDs | Bill Gray San Jose will convert 100 lights this spring and is seeking $20 million in stimulus money for up to 25,000 more. City Transportation director Jim Helmer hopes to change all 62,000 streetlights by 2022. Besides cutting the $4 million annual electric bill for streetlights, San Jose’s LEDs will have transmitters and receivers so they can alert the city when maintenance is needed. They can be dimmed overnight, brightened when pedestrians are near and flash to guide first responders.
As part of a pilot program, the city of Raleigh, N.C. last year replaced nine streetlamps in its downtown area with lights made by Beta LED
Elsewhere: • If Milwaukee gets $14 million in stimulus funds it’s seeking for the project, it will replace 6,700 of its 67,709 streetlights with LEDs, says Bob Bryson, chief street-lighting engineer. • Missouri City, Texas, wants to convert 75% of its 31,000 streetlights to LEDs. Public Works director Scott Elmer says electricity for each would be about $7.50 a month, compared with $14.77 for incandescent lamps. • Urbana, Ill., is testing LED streetlights. Public works director Bill Gray says their lifespan is about 14 years, compared with two years for current lights. “We need to be sold on the … uniformity of the light,” he says. Glendale, Ariz., isn’t using LED streetlights, but it’s the first U.S. city with an automatic system that monitors 19,270 streetlights and alerts the city when one is out. Transportation director Jamsheed Mehta says the result is “significant savings” in fuel and emissions.
Solar panels could power them, Helmer says, so higher costs — about $1,000 for an LED streetlight compared to $250 for a traditional one — can be quickly offset and excess energy fed back into the power grid.
2 Feb 2009 │ DOE releases Phase III of Oakland Demonstration Report on LED street lights Energy savings increased by 25% relative to Phase II (LED luminaire wattage dropped from 78 W to 58 W) and by 52% relative to the baseline system (from 121 W to 58 W).
“City budgets are being squeezed … and 50% energy savings is significant,” says Christopher Ruud of Beta LED, a Racine, Wis., company that works with cities on LED projects.
The U.S. Department of Energy (DOE) has released the Phase III report from the solid-state lighting (SSL) demonstration of LED street lights in Oakland, CA.
This GATEWAY demonstration report, prepared by Pacific Gas & Electric and Energy Solutions, provides an overview of project results measured over a 12-month period, including comparison to Phase II luminaires, energy consumption and illuminance levels, and economic analysis.
A spokesperson for Peduto said the proposal’s approval timeline is not clear, as it may get held for a public hearing. He said it will come up for some form of action next week, but likely will be held for true action until January.
In this project, four LED luminaires on one of the Phase II streets were replaced with next-generation LED luminaires (58 W) from the same manufacturer, with the same chip and driver.
Over six months ago, Councilman Peduto launched a trial of LED lights along the Walnut Street business district. Today, he is submitting a proposal for Pittsburgh to replace all existing street lights with 200 W LED lights.
Key findings include:
The benefits listed in the Councilman’s report are:
•
•
The plan would save taxpayers more than $2.5 million annually in energy and maintenance costs. In addition, the conversion would lead to the reduction of more than 984 lbs of carbon dioxide emissions each year.
Pittsburgh currently spends $3.2 million each year in electricity costs for street lights. With the reduction of 137 W of energy used by each of the 40,000 lights, taxpayers will save $1.92 million per year in energy costs. Pittsburgh currently spends approximately $1 million each year maintaining our street lights. An HPS bulb has 2-4 year life span versus 10-15 years for an LED light. Additionally, an LED fixtures burns out one LED at a time, which is in contrast to the current lights HPS lights which completely blow out all at once. This is expected to save taxpayers approximately $700,000/year in maintenance costs. A 200W LED light only uses 93W of power. However, the existing 150 W high power sodium (HPS) bulbs use ~230 W (includes the ballast) of power. Therefore, over the year, the City of Pittsburgh will save 600 kWh of energy. This translates into 984 lbs of carbon dioxide emissions eliminated by switching all lights to LED. LED lights turn on and off instantly with no warm up time. The existing HPS bulbs have a slow warm up period that is a waste of energy. Additionally, the existing sodium bulbs contain mercury in the ballasts, LED lights have no mercury. LED lights produce a white light that stimulates the rods and the cones of our eyes. This creates a higher quality white light, while using less energy than the HPS lights that only stimulate the cones of our eyes and produce a yellow-orange light.
“This is a plan that saves taxpayers millions of dollars, while also protecting the environment,” said Councilman Peduto. “LED street lights use less energy, require less maintenance, provide a brighter light, reduce carbon dioxide emissions, and contain no mercury. This is a win-win situation.”
Thecosts Each LED light costs ~$500 to purchase. Additionally, it would cost about $100 in labor/light in conversion costs. Therefore, the cost to replace 40,000 lights would be approximately $24 million. With an annual savings of $2,620,000 upon complete conversion, the City can fully payoff the LED conversion in 10.5 years, said the report.
• •
Energy savings increased by 25% relative to Phase II (LED luminaire wattage dropped from 78W to 58W) and by 52% relative to the baseline system (from 121W to 58W). Luminaire cost decreased by 34% between Phase II and Phase III (from $610 to $400). Lighting performance was maintained.
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For more details, download the complete Phase III demonstration report at www.netl.doe.gov/ssl. This commercial LED lighting demonstration is one of a number of DOE GATEWAY demonstrations that showcase high-performance LED products for general illumination.
09 Feb 2009 │ Pittsburgh councilman releases plan to convert city street lights to LEDs If the city approves the proposal, it would save taxpayers more than $2.5 M annually and allow manufacturers to submit test products.
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At a press conference Monday afternoon, Pittsburgh (Pennsylvania) City Councilman William Peduto released a plan to convert all 40,000 city street lights to LED lights. •
3) The City should immediately submit an application with the State through the Guaranteed Energy Savings program. 4) The City should determine programs to properly dispose of the existing HPS lights. This could be done through the United States Agency for International Development (USAID) or a similar program.
Pennsylvania’s Guaranteed Energy Savings Agreement (GESA) can be utilized to cover the upfront costs of the LED conversion. According to the State, “Projects will be implemented where, through simple-payback analysis, cost savings resulting from energy conservation improvements exceed the associated financing. In other words, these guaranteed savings are used to cover operating budget finance payments over a period not to exceed fifteen years." Request for proposals If the plan is approved, it recommends:
1) the City should issue a Request for Proposals (RFP),immediately requesting that all interested companies provide the City with ten test lights to install throughout business districts in the City for a six month trial (February 1, 2009 – July 31, 2009). During the trial period, measurements should be taken to determine the luminous intensity and the energy produced. Solar powered lights and those with photo-sensitive detectors that lessen the light during dusk and dawn should be included in the trial. 2) The City should award the contract no later than August 31, 2009, based on required conditions of the RFP process, reliability through trial phase, and long term financial and environmental impact. The contract should require work to begin no later than October 1, 2009 and completed by December 31, 2010.
LOS LED JAPON
01 Feb 2009 │ Japanese development to be lit entirely by LEDs A residential development of more than 200 houses in Azabu no Oka, Japan, will use LED fixtures for all its outdoor lighting. The outdoor areas of a residential housing development in Azabu no Oka, Japan, will be lit entirely by LEDs, according to a detailed series of articles on the Nikkei Tech-On. The development is being built by Toyota Smile Life Inc and has been dubbed Toyota “LED Town.” The LED lights being installed at the development, located in Miyoshicho, Aichi Prefecture, Japan, will illuminate public areas including streets, sidewalks, parks and bridges, as well as private areas such as the gate, porch and walls of each house. A total of 204 houses will be built, and more than 20 have already been completed. Each of the houses has four to five LED exterior lamps that light the roads and pathways as well as exterior walls of each house. The LED street lamps are installed only at the intersections of main roads inside the subdivision. When completed, the development will have a total of about 1000 LED lights, all using white LEDs with a color temperature of slightly less than 3,000K to create a “relaxing and warm atmosphere,” according to the article. The LED fixtures are being supplied by Japanes manufactured according to the fixture maker .
Toyota LED Town.
NOTAS TECNICAS
LED street light design technologyAlliance Optotek’s street light design takes into account the LED’s thermal, optical, power and mechanical properties Over the past few years, LED light-out efficiency has largely risen from 35 lm/W (2006) to 100 lm/W (Q1’2009). From the viewpoint of LED efficiency increasing, LED products that replace traditional lighting have been deeply anticipated, especially in high power consumption products. Due to the lighting market business being very large, there are many new companies joining in recent years. However, LED product quality has become a very big issue, especially in new companies’ products since these new companies are not experts in the lighting field. CCT (K)
Response
Lightout theory
Light direction
Life
Reliability
Vibration resistant
Specific direction
50,000 hours
Disadvantages
LED
2600~10,000
<1 sec
Semi condutor
High
High
High price
FCL
4000~8000
<60 sec
Hg vapor
Full direction
6000 hours
Middle
Low
Hg pollution, broken
Halogen
2500~3000
<150 sec
Heating
Full direction
1000 hours
Low
Low
Power exhaust, short life, fragile
Table 1. Comparison of LED and traditional lamp
Fig. 2 In the past two years, LED street lights have been widely discussed since there exists a very large market and the LED’s power saving performance is obvious especially in replacing the 250 W or 400W mercury lamp. To build an LED street light, the key issue is needed to reach and meet a specific specification, for example, it needs to guarantee 5 years (since everyone knows LED life is 50,000 hours), the light pattern has a specific request to meet the roadway regulation specification, dust and water-resistant has to reach IP65, mechanism strength needs to be enough, etc. Based on these requests, to design the LED street light, one needs to consider the thermal, optical, power and mechanism. LED life depends on the LED junction temperature (Figure 1). Cree has announced data to show the relationship of life versus light maintenance for different junction temperatures. Therefore, to guarantee 50,000 hours life, the LED junction temperature has to be controlled under 75C.
Fig. 1 On the other hand, LED’s characteristics are obviously different from the traditional lamp, ex. Halogen lamp efficiency raising depends on the heat increasing, but LED is very afraid of heat: worse LED temperature, worse light output. LED light direction is specific, not same as traditional lamp full direction. All of the differences between LED and traditional lamps are shown in Table 1. Since there exists obvious differences, the thermal, optical, power, mechanism and control become very important as one designs LED lighting products.
Fig. 3 (patent pending) As for the illumination uniformity of roadway, the batwing light pattern is inevitable. The cut-off light pattern for glare limitation is also required. The other important subject is about both the driver (power) design and LED light module design: we know that each LED has a little different drive voltage and we can not guarantee all of the same drive voltage LEDs have been built into the street light. So, a worse circuit design will induce a nonuniform current to drive the LED, which will impact
each LED’s life. AOP knows all of the design issues that will directly affect the LED street light product quality, hence, AOP combined thermal / optical / power / mechanism to do a overall design to make sure of street light quality. LED street light design and analysis An excellent LED lighting product has to consider: thermal, optical, power and mechanism (industry design). 1.Thermal design As we know, worse LED junction temperature, worse LED life-time. To guarantee 50,000 hours life-time, AOP has designed a street light in which the LED junction temperature is controlled under 75°C and heat sink temperature variation is constrained below 2°C to ensure all of LEDs applied on the street light can reach the same life. AOP has used a DOE method to analyze the effects of the fin pitch, thickness, height of heat sink and found a best solution; see Fig. 2. We found a reasonable heat sink size to reach designed target, LED junction below 75°C and heat sink temperature variation under 2°C.
Fig. 5 which can reach 4 times mounting height (max. cd located on 60 degree) and illumination uniformity is larger than 0.33 required; see Figs. 4 and 5. This is a case study for an AOP street light installed on 8 m pole height, and projected on 32 m roadway length. The illuminance distribution is shown in Figure 4. This light optical pattern can largely reduce the street light installation quantities as on a specific roadway length. By the way, the optical pattern also met the cut-off requirement. AOP also provided an .IES file for the designer to design the different roadway project.
Fig. 4 2. LED street light optical pattern design As the above mentions, if the street light wants to apply on the roadway, then it needs to meet roadway illumination specification, i.e., the optical pattern has to meet the uniformity (>0.33) of roadway, and glare rating. Except to meet the roadway regulation specification, how to let the light output project on the large roadway area is also important course. Since if your street light only can project on 3 times mounting height region, that means as mounting height is 6m, then the light output only distributed 18 m roadway length. So, as there existed a specific length roadway needs to install street light, then you need more street lights to apply to meet the roadway specification and avoid the zebra pattern appearing. Hence, to avoid increasing the quantities of street light, AOP designed a batwing optical light pattern (patent pending, the pattern has measured by ITRI, see Fig. 3),
Fig. 6 96 Watt, 7156 Lm, 5200K Max.
29 Lx
Avg.
13 Lx
Min. Uniformity (Min./Avg.)
4.5 Lx 0.35
Table 2. Uniformity
3. Mechanism and industry design (patent pending) In AOP’s street light, we also considered the moving and installation convenience; see Figs. 5 and 6. In the power space, we have installed a socket, so the operator can easily install the city cable into the socket and its process is 100% same as traditional lamp installation. By the way, the bow shape design in the front of luminaire can let the operator easily moved. This luminaire is dustand water-resistant and its rating reaches IP 65.
4. LED light module and driver power design As we know, each LED has a little different drive voltage, so avoiding the non-uniform current appearing on each LED becomes a very important key design. Although, every street light supplier says their power supply is using constant current output, actually after we measured the LED current, we found there existed a very large variation; see Table 2.
Conclusion AOP’s street light design is combined of thermal, optical, mechanism and power, hence, all of the possible effects on the LED life are considered. That is why we are very confident our street light product. By the way, based on ITRI measurement data, AOP street light luminaire’s efficacy already reaches 72.8 lm/W; its performance almost cannot be found in the world at this time. About the Author Tsung-Chieh, Chen, is in the System Integration Development Division for Alliance Optotek Corp., No. 5, Lane 191, Chung-Ho St., Chupei City, Hsinchu 30267, Taiwan;
Fig. 7 LED
1
2
3
4
5
6
ILED(mA) 514.0 348.0 378.0 235.0 207.0 273.0 Table 3. Current of different LEDs
That was due to the LED light module is designed by series and parallel combined circuit; see Fig. 7. So, if each LED drive voltage is not the same, then the LED will get different current even though you used the constant current design. Hence, if one of then LEDs failed, then it will be quickly extended to others, which was due to the other LED passing more current.
Fig. 8 (patent pending) AOP’s street light is different from other suppliers’ design; we used the multi-channel circuit design (patent pending) on both the power and LED light module (see Fig. 8); per channel power output constant current to the single series LEDs to ensure each LED passed the constant current. The measured result is shown in Table 3, where a very uniform current passes to each channel. The constant current of using multi-channel design will not be influenced even though the varied LED voltage. Channel ILED (mA)
1
2
3
4
5
6
7
8
301.1 300.8 298.2 301.5 302.8 298.4 297.7 298.1
Table 4. Current of multi-channel design
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