LEDs - Past, Present and Future

1. LEDs - Past, Present and Future FAA Eastern Region Airports Conference Thursday, 3 March 2011 Presented by Pete Butler, P.E.

2. Agenda • Definition of LED • Characteristics of LED Fixtures • Evolution of LEDs in Airfield Lighting Systems • Recent Developments • Future Implementation • Design Considerations • Roundtable Discussion

3. 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

4. Characteristics of LEDs Positive Characteristics • Lower energy consumption • Longer lifetime • Improved robustness • Smaller size • Faster switching • Greater durability • Higher reliability + +

5. 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 (-) (-)

6. 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

7. 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

8. 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

9. 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

10. 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

11. 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

12. 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

13. 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

14. 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

15. 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

16. 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

17. 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

18. 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

19. 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

20. 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 $$$

21. 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

22. 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

23. 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

24. 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

25. THANK YOU