LED ROADWAY LIGHTING

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LED ROADWAY LIGHTING

• Presented by DaTran Lighting

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AGENDA

• Of the numerous illumination platforms currently
  available, only Solid State Lighting offers our
  nation the potential to save energy and enhance
  the quality of our environment.

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AGENDA

• Introduction and Highlights
• - Solid State Lighting standards
• - Luminaire efficiency
• - Photopic / Scotopic considerations
• - Thermal Management
• - Lightning protection
• - LED roadway and post lighting examples

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Solid state lighting standards

• All lighting products used in the United States
  are subject to the standards governing safety and
  performance. Solid-state lighting (SSL) is an
  emerging technology that is difficult to qualify
  under the existing standards covering HID roadway
  lighting. As a result, new standards and testing
  methods have been developed for solid state
  luminaires.
• LM-79, IESNA Approved Method for the Electrical
  and Photometric Measurements of Solid-State
  Lighting Products, specifies procedures for
  measuring total luminous flux, electrical power,
  luminous efficacy, and chromaticity of solid
  state lighting.
• LM-80, IESNA Approved Method for Measuring
  Lumen Depreciation of LED Light Sources,
  specifies procedures for determining lumen
  depreciation of LEDs and LED modules (but not
  luminaires) related to effective useful life of
  the product.

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Luminaire efficiency

• The inherent directionality of LED emitters
  make them an ideal choice for roadway lighting.
  All conventional roadway HID fixtures have a low
  CRI (color rendering index) and require the use
  of reflectors / refractors which can be up to 40
  inefficient. This inefficiency substantially
  reduces a HID lamps actual lumen and foot candle
  output when measured on the ground.
• LEDs, on the other hand, have a high CRI and
  emit light only in one direction without the need
  of a reflector. This allows for unprecedented
  control of the light patterns on the ground and
  the near total elimination of wasted light. It
  demands, however, that lighting designers are
  cognitive of these features up-front and not rely
  on the 360 nature of conventional bulb
  technology. Slides 6-9 demonstrate these
  concepts.

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Luminaire efficiency
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Luminaire efficiency

• TYPICAL 150 WATT HIGH PRESSURE SODIUM STREET
  LIGHT
• MEASUREMENT OF LUMENS REACHING THE GROUND
• TOTAL LUMEN OUTPUT OF HPS LAMP 22000lm 100
• DOWNWARD STREET SIDE 6656lm 30.3
• DOWNWARD HOUSE SIDE 6057lm 27.5
• DOWNWARD TOTAL LUMENS 12712lm 57.8
• REFLECTOR INEFFICIENCY -9278lm 42.2

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Luminaire efficiency
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Luminaire efficiency
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Luminaire efficiency

• The efficiency of LED luminaires is based on its
  calculated efficacy. Actual measured efficacy can
  be difficult to calculate as LED and power supply
  performance vary greatly and can offset the
  efficacy value.
• All LED products should be evaluated with
  photometric and IES files to verify the true
  performance of the LED luminaire.

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Photopic / Scotopic considerations in lighting

• Low light/Starlight - Scotopic vision (rods)
• Interior lighting - Photopic vision
  (cones)
• Outdoor lighting - Mesopic vision (rods and
  cones)

Visible light measurement is based on a photopic
standard developed by the CIE.  Photopic
measurement is the human retinal response to
visible light. Lumens, foot-candles, lux, etc.,
are all photopic measurements. Lower the
photopic light level and retinal sensitivity
begins to shift into a very low light energy
region, defined as human scotopic response and is
only active in very low starlight
conditions. The area between photopic and
scotopic is known as mesopic, which all outdoor
lighting falls under.
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Thermal Management

• Thermal management and an awareness of the
  operating environment are critical when
  considering an LED luminaire for general
  illumination.
• Successful LED luminaires will employ adequate
  heat sinks and an Advanced Processor based
  Thermal Management System that prevents the LEDs
  from overheating.
• Maintaining the LED junction temperature as low
  as possible and within the manufacturers
  specification is necessary in order to maximize
  the performance and longevity of post and street
  light luminaires. The following slide provides
  an example of an efficient thermal design by the
  Niland Fixture Company.

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Thermal Management
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Lightning protection
Electronic power supplies and LED luminaires are
sensitive to power surges and impulse lightning
events. Without sufficient protection, these
events will destroy an LED luminaire. Electronic
power supplies and LED luminaires need to be
rated for 15kV and pico second response time in
order to prevent damage. Additionally, all
power supplies should contain components rated
for 100,000 hour lifespan. No short life
components such as electrolytic capacitors should
be used in the design as these will fail in less
than 2000 hrs of use.
Lightning protection circuit
Lightning damage to unprotected power supply
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HID vs LED
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LED street light fixtures
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LED street light fixtures
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LED post light fixtures
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LED post light fixtures
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LED high bay fixtures
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Questions and comments

• Thank -You For Your Time Today