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LEDs - Past, Present and Future. FAA Eastern Region Airports Conference Thursday, 3 March 2011 Presented by Pete Butler, P.E. Agenda. Definition of LED Characteristics of LED Fixtures Evolution of LEDs in Airfield Lighting Systems Recent Developments Future Implementation

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leds past present and future
LEDs - Past, Present and Future

FAA Eastern Region Airports Conference

Thursday, 3 March 2011

Presented by Pete Butler, P.E.

agenda
Agenda
  • Definition of LED
  • Characteristics of LED Fixtures
  • Evolution of LEDs in Airfield Lighting Systems
  • Recent Developments
  • Future Implementation
  • Design Considerations
  • Roundtable Discussion
definition of led
Definition of LED
  • Light Emitting Diode
  • Semiconductor light source
  • Within device, electrons

jump a gap to recombine with

electron holes

  • During jump, energy is released in form of photons
  • Result - phenomenon called electroluminescence
  • Color of LED determined by energy gap of semiconductor
characteristics of leds
Characteristics of LEDs

Positive Characteristics

  • Lower energy consumption
  • Longer lifetime
  • Improved robustness
  • Smaller size
  • Faster switching
  • Greater durability
  • Higher reliability

+

+

characteristics of leds1
Characteristics of LEDs

Negative Characteristics

  • More expensive
  • Require more precise current
  • Sensitive to high temperatures
    • Light output decreases
    • Light spectrum in negatively impacted
    • Heat sinks / beveled or ridged exterior

(-)

(-)

evolution of leds in airfield lighting systems
Evolution of LEDs in Airfield Lighting Systems
  • Implemented in clusters to create a light source
  • LED-lamped taxiway elevatededge lights emerged in early 2000s
  • Original fixtures resembled lighthouses with lamp / LED

cluster at base of fixture

  • Inherent maintenance issues
  • Water infiltration
evolution of leds in airfield lighting systems1
Evolution of LEDs in Airfield Lighting Systems
  • LED technology improved, airport interest increased - additional manufacturers developed edge lights
  • Mid 2000s, at least three vendors of edge lights
  • Fixtures better resemble typical

edge lights

evolution of leds in airfield lighting systems2
Evolution of LEDs in Airfield Lighting Systems
  • Fixtures installed in existing 5kV airfield lighting environment
  • LEDs are DC-based devices that operate in milliamp range
  • As LED technology improved, experts discussed alternate power sources
  • Test beds reviewed

alternate power

sources

evolution of leds in airfield lighting systems3
Evolution of LEDs in Airfield Lighting Systems

Prescott Municipal Airport Testing

  • Modified LED edge lights, incandescent edge lights, and LED guard lights
  • Modified edge lights – 2.8A max
  • 0.28/0.84/2.8A circuit vs. 4.8/5.5/6.6A circuit (traditional)
  • Testing proved successful, system still operating after five years with no fixture failures
evolution of leds in airfield lighting systems4
Evolution of LEDs in Airfield Lighting Systems

Hartsfield-Jackson Atlanta International Airport Test Bed (2006 – present)

  • Modification to Standards / airport funded
  • Re-used existing series circuit infrastructure
  • DC-based system with LED taxiway centerline and edge lights (600V DC)
  • Small, rack-mounted powersupply
  • Fixtures directly connected tocircuit
evolution of leds in airfield lighting systems5
Evolution of LEDs in Airfield Lighting Systems
  • LED Equipment has evolved significantly
  • Lighting equipment available
    • Obstruction Lights
    • Elevated and in-pavement taxiwayedge lights
    • Taxiway centerline lights
    • Elevated and in-pavement guard lights
    • Medium-intensity runway edge lights
evolution of leds in airfield lighting systems6
Evolution of LEDs in Airfield Lighting Systems
  • Other equipment available
    • Signage
    • Wind Cones
    • REILS
  • LED-supporting equipmentavailable
    • Smaller constant current regulators
    • Isolation transformers
    • Sign Retrofit Kits
recent developments
Recent Developments

Orlando International Airport Test Bed (2010 to present)

  • DC-powered circuits, pulse width modulated
  • Two interleaved circuits
  • LED Taxiway Centerline Lights
  • No isolation transformers
  • Rack-mounted power supply
recent developments1
Recent Developments

False River Airport Test Bed (2010 to present)

  • Funded by State of Louisiana
  • DC power supply fed by batteries connected to solar panels
  • Two interleaved circuits
  • LED Taxiway Edge Lights
  • Rack-mounted power supply
recent developments2
Recent Developments
  • Runway centerline and touchdown zone lights certified over last year
  • Moratorium on acquisition andinstallation
  • Pilots – fixtures too bright at lower steps
  • FAA tested circuits and verified operation
  • Result - LED fixtures brighter at lowersteps than incandescent fixtures
  • Light curves differ between fixture types
recent developments3
Recent Developments
  • Incandescent fixture output is linear, LED output is non-linear
  • Engineering Brief 67C recently issued, moratorium lifted
  • Light Dimming Curve modified for white LED lights only
recent developments4
Recent Developments
  • Airport / manufacturer focus on runway edge lights
    • Will impact majority of airports
    • Main restriction is intensity of white LEDs
    • High-intensity elevated edge lights anticipated in 2011
    • FAA requirement for in-pavement light to match elevated fixtureswill hinder production
future implementation
Future Implementation
  • System Approach needed
    • Embrace LED properties and maximize efficiency
    • Cease adapting to existing environment / infrastructure
  • Two approaches evolving
    • Lower current system (possible maximum current of 2.8A)
    • DC-based system with pulsewidth modulation
design considerations
Design Considerations
  • Consider LEDs for lights, signs, wind cones, etc.
    • Maximize energy savings
  • Interspersing of LED and incandescent fixtures - not acceptable
  • Segmenting of circuiting / operations
  • Separate circuits for incandescent and LED fixtures
  • Match isolation transformer sizes to maximize efficiency
design considerations1
Design Considerations
  • Analyze impact of circuit load on circuits, vault, airport
  • Perform Benefit Cost Analysis (BCA)
    • Higher material cost
    • Longer lamp life
    • Lower energy consumption
    • Higher replacement cost
  • Training/expertise of maintenance staff

$$$

design considerations2
Design Considerations
  • Arctic Kit or no Arctic Kit
    • Apprehension to use LED lights, because fixture won’t melt snow
    • Snow melting is inherent property of incandescent fixture
    • Arctic kit negates lower energy consumption
    • Selection impacts circuit load, regulator size
    • Snowplowing impacts
design considerations3
Design Considerations
  • Test Beds – w/ and w/o Arctic Kit
    • Multiple sites in Midwest
      • Taxiway Edge Lights
      • Guidance Signs
    • Current Testing at JFK
      • Taxiway Centerline Lights
      • Multiple vendors
roundtable discussion
Roundtable Discussion
  • Denise De Natale - Director of Sales, Multi Electric Manufacturing Inc.
  • Galen Dixon - Regional Sales Manager, ADB Airfield Solutions
  • Tony Mancini - Director of Marketing, Cooper Crouse-Hinds
roundtable discussion1
Roundtable Discussion
  • Topics of Discussion
    • Feedback / Lessons Learned on existing LED installations
    • Interpretation / Impacts of recently issued Engineering Brief 67C
    • Recent developments with LEDs / emerging equipment
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