Boletín de noticias Led Marzo 2009

Ledding the future

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, white-

light 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,

LOS LED EN USA

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.

Clinton and LA Mayor Villaraigosa

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.

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-the-

art 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.

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:

• 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. 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.

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.

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.

“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.

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.

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

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).

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.

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.

Key findings include:

• 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.

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.

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.

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.

The benefits listed in the Councilman’s report are:

• 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.

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.

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.

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.

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.

“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.”

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.

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.

LOS LED JAPON

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

Light-

out

theory

Light

direction Life Reliability

Vibration

resistant Disadvantages

LED 2600~10,000 <1 sec Semi

condutor

Specific

direction

50,000

hours 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. 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.

NOTAS TECNICAS

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. 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 non-

uniform 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. 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. 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. 6

96 Watt, 7156 Lm, 5200K

Max. 29 Lx

Avg. 13 Lx

Min. 4.5 Lx

Uniformity

(Min./Avg.) 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 dust-

and 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.

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 1 2 3 4 5 6 7 8

ILED

(mA) 301.1 300.8 298.2 301.5 302.8 298.4 297.7 298.1

Table 4. Current of multi-channel design

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;

ECOLED DESARROLLOS S.L. Madrid Paseo de la Castellana, 153 28046 Madrid Oficina de atención al cliente Tel. 914 451 936 / 914 455 900 Fax 910 180 491(Madrid) www.ecoled.es info@ecoled.es .

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