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LED street light |
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LED street light－Design
and style
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LED street light beam
pattern
An LED street light is
an integrated light that uses
LEDs as
its light source. These are considered
integrated lights because, in most
cases, the
luminaire and the
fixture are not separate parts
(except LEDGine-based luminaires). New
in manufacturing, the LED light cluster
is sealed on a panel and then assembled
to the LED panel with a
heat sink to become an integrated
lighting fixture.
Different designs have been created
that incorporate various types of LEDs
into a light fixture. The current trend
is to use high power 1 watt LEDs, but
some companies use low power LEDs in
their products, including several low
power LEDs packed together to perform
the same purpose as a single high power
LED. The shape of the LED street light
depends on several factors, including
LED configuration, the heat sink used
with the LEDs, and aesthetic design
preference.
Heat sinks for LED street lights are
similar in design to heat sinks used to
cool other electronics such as
computers. Heat sinks tend to have as
many grooves as possible to facilitate
the flow of hot air away from the LEDs.
The area of heat exchange will directly
affect the lifespan of the LED street
light.
The lifespan of an
LED
street light is determined by its light
output compared to its original design
specification. Once its brightness
decreases by 70 percent, an LED street
light is considered to be at the end of
its life.
Most LED street lights have a lens on
the LED panel, which is designed to cast
its light in a rectangular pattern, an
advantage compared to traditional street
lights, which typically have a reflector
on the back side of a
ledlightssuppliers.org. In this case
much of the luminance of the light is
lost and produces light
pollution(www.streetlighting.org) in the
air and surrounding environment. Such
street lights can also cause glare for
drivers and pedestrians.
A drawback of LED focus panels is that
most light is directed to the road, and
less light to the footpaths and other
areas. This can be addressed by the use
of specialised lens design and
adjustable mounting spigots.
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| The primary appeal of LED
street lighting is energy efficiency
compared to incandescent bulbs of the
same luminance. Research continues to
improve the efficiency of newer models.
One such advance can be found in a
street light product created by Lighting
Science Group. One model of LED street
lights produced by this group is up to
60 percent more efficient than previous
models, lasts for 12 years, and allows
for cost recovery through energy savings
in only three years.
An LED street light based on a 901
milliwatt output LED can normally
produce the same amount of (or higher)
luminance as a traditional light, but
requires only half of the power
consumption.
As the LED lighting fixtures normally
produce less lumen/Watt illumination it
is very crucial to have a well
distributed illumination pattern in
order to do the same job as higher
lumen/Watt conventional fixtures. So a
good design of LED street lights is to
point different LEDs in one fixture to
different target points. A good example
of such design might be found in
www.azelectronics.com.au |
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LED
street light－Advantages
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Advantages of using
LED lights:
- Low power consumption and long and
predictable life time
The lifetime of Led Street lights is
usually 10 to 15 years which is three
times the life of current technologies
adopted. The LED’s also have low
maintenance cost which adds to the
benefit.
- Dimming
LED’s can be dimmned at times when the
use of the street lights is less like
late nights and early mornings.
- Small package size
- High color rendering
The color rendering index is the ability
of a light source to correctly reproduce
the colors of the objects in comparison
to the normal light source.
- Quick turn on and off
Unlike flourescent bulbs which take time
to heat up once switched on
LED’s
turn on instantly. LED’s don’t have
problem with hot ignition
- RoHS complaint free
LED’s dont contain Hg/Pb and dont emit
poisonous gases
- Less attraction to nocturnal insects
Insects are sensitive to the UV-blue and
green region of the light spectrum.
Nocturnal insects are attracted to the
emission of UV-blue and green light from
conventional light sources. White LEDs,
however, emit light in a small peak in
the blue range and smaller in the green
range, so nocturnal insects are less
attracted to such light sources.
- Easy to design non glare lighting
equipment
Most LED street lights have a lens on
the LED panel, which is designed to cast
its light in a rectangular pattern, an
advantage compared to traditional street
lights, which typically have a reflector
on the back side of a high-pressure
sodium lamp. In this case much of the
luminance of the light is lost and
produces light pollution in the air and
surrounding environment. Such street
lights can also cause glare for drivers
and pedestrians.
- Higher light input even at low
temperatures
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