1. Overview of Recent TechnologyTrends in Energy-Efficient Lighting N. Narendran, Ph.D. Lighting Research Centre Rensselaer Polytechnic InstituteTroy, NY 12180 USAApril 27-28, 2009

2. AcknowledgmentsUSAID/SARI/PA ConsultingSLSEALRC faculty, staff, and studentsLRC program and project sponsors 2009 Rensselaer Polytechnic Institute. All rights reserved. 2 3. Electric lighting historyIn 1879, Thomas AlvaEdison demonstratedthe first successful lightbulb.Over the past 125 years,incandescent and gas dischargetechnologies have provided manyshapes and sizes of light sourcesfor a variety of lightingapplications. 2009 Rensselaer Polytechnic Institute. All rights reserved. 3 4. Light source technologiesSpectral powerIncandescent distribution (SPD)1.21.0Relative Energy0.80.60.40.20.0 350450 550650750 Wavelength(nm) Fluorescent 1.2 1.0 Relative Energy 0.8 0.6 0.4 0.2 0.0350 450 550 650750 Wavelength(nm) High PressureSodium 6 5 Relative energy 4 3 2 1 0350 450 550 650 750Wavelength(nm)my.dteenergy.com/products/images/roadway1.jpg 2009 Rensselaer Polytechnic Institute. All rights reserved. 4 5. Luminous flux and efficacy 1.0 0.8 Relative EnergyLumen and lumens per watt are two key0.6metrics commonly used in the lighting0.4industry to quantify performance of light0.2sources. 0.0350 400 450 500 550 600 650 700 750 Wavelength(nm)Lumen: The luminous flux accounts forthe sensitivity of the eye by weighting theradiant power at each wavelength withFlux () = 683SV d (lm)the human eye response function.Lumens per watt: Luminous efficacy of alight source is the total luminous fluxEfficacy = / W (lm/W)emitted by the lamp divided by the totallamp power (electrical) input. 2009 Rensselaer Polytechnic Institute. All rights reserved.5 6. Light source technologiesIncandescent and halogen lightsources range in efficacy from 2to 30 lm/W.Fluorescent light sources range inefficacy from 25 to 105 lm/W.High-intensity light sources rangein efficacy from 25 to 150 lm/W. 2009 Rensselaer Polytechnic Institute. All rights reserved.66 7. IncandescentFilament heating produces light Only 5% of the total energy input is converted to light and the rest is heat Very inefficientEfficacy Generally around 15 lm/WColor CRI = 95+ CCT = 2500K 3000KLife (average rated) 750 2000 hours Dimming can extend life 2009 Rensselaer Polytechnic Institute. All rights reserved.7 8. HalogenA halogen lamp contains an inert gasand a small amount of halogen.Efficacy PAR and MR Lamps (line or low voltage) 10 to 25 lm/W IR PAR Lamps (Infrared reflector) 20 to 30 lm/WColor CRI 95+ CCT Typically 3000KLife (average rated) 2000 hours Shortens if consistently dimmed below 80% 2009 Rensselaer Polytechnic Institute. All rights reserved. 8 9. FluorescentA fluorescent lamp is a low-intensity gas-discharge lampthat uses electricity to excite mercury vapor to produceultraviolet (UV) radiation that causes a phosphor tofluoresce and produce light. Linear fluorescent lamps (LFL) and compact fluorescent lamps (CFL) are popular choices for conserving energy. About 20% to 30% of the total energy input is converted to light. 2009 Rensselaer Polytechnic Institute. All rights reserved.99 10. Compact fluorescent lamp (CFL)Types: Pin-base for dedicated fixtures Screw-base self-ballastedEfficacy: 25 to 60 lm/WColor CRI = 82 typical CCT = 2700K, 3000K, 3500K, 4100K, 5000KLife 6,000 to 10,000 hours Frequent on-off switching can reduce life significantly Dimming is possible but can reduce life 2009 Rensselaer Polytechnic Institute. All rights reserved. 10 11. Linear fluorescent lamp (LFL)Lamp Efficacy Ranges from 65 to 105 lm/WColor CRI = 82 typical CCT = 2700K to 5000KLife 20,000 to 30,000 hours Frequent on-off switching can reduce life significantly Dimming can reduce life 2009 Rensselaer Polytechnic Institute. All rights reserved. 11 12. Ballasts for LFLFluorescent lamps require aballast to operate MagneticLow frequency (60 Hz) operationMay produce audible humMay produce noticeable lamp flickerInefficient lamp operation ElectronicHigh frequency (20 to 60 kHz)operationQuietNo noticeable lamp flickerMore efficient lamp operation 2009 Rensselaer Polytechnic Institute. All rights reserved. 12 13. High intensity discharge (HID)Metal halide lamps produce light bypassing an electric arc through a mixtureof gases, which causes a metallic vapor toproduce radiant energy. It contains a high-pressure mixture of argon, mercury, and a variety of metal halides in a compact arc tube. About 24% of the total energy input is converted to light.Three types of HID lamps:www.holophane.com Mercury vapor lamp Metal halide lamps High-pressure sodium (HPS) lamp 2009 Rensselaer Polytechnic Institute. All rights reserved. 13 14. Ballasts for HIDMetal halide lamps require ballasts toregulate the arc current flow anddeliver the proper voltage to the arc. Probe-start metal halide: Contains a starting electrode within the lamp to initiate the arc when the lamp is first lit. Pulse-start metal halide: No starting electrode but has a special starting circuit to generate a high-voltage pulse to the operating electrodes. 2009 Rensselaer Polytechnic Institute. All rights reserved. 14 15. Lighting controlsManual controls Wall switch: on or off DimmersAutomatic controls Time clocks Occupancy sensors Infrared Ultrasonic Dual technology Panel relays Centralized controls 2009 Rensselaer Polytechnic Institute. All rights reserved.15 16. Efficacy and energy savingsEnergy use depends on the connected load andtime of use Watt-hoursMYTH: High efficacy light sources always savemore energy than low efficacy light sources. Spatial light not reaching the application area is wasted light (energy) Temporal light beyond the required time is wasted light (energy) 2009 Rensselaer Polytechnic Institute. All rights reserved.16 17. Energy Conservation 2009 Rensselaer Polytechnic Institute. All rights reserved. 17 18. Different forms of luminous efficacyLight source (lamp) efficacy: Total lumensout of the light source divided by the totalinput power to the light sourceLight source + ballast efficacy: Totallumens out of the light source divided by thetotal input power to the ballastLuminaire efficacy: Total lumens exitingthe luminaire divided by the total inputpower 2009 Rensselaer Polytechnic Institute. All rights reserved. 18 19. Luminaire efficacyIn this example, the total luminaire efficiency is 33%to 54%.A 60 lm/W CFL would yield: 19 to 32 lm/W final system efficacy in these luminaires IR Halogen PAR lamp would be a better choice than combinations A to J 2 4 W C F L F ix tu re100% Flux exiting the fixture80%60%40%CFL20% 0% A BC DE FG H IJKL 2009 Rensselaer Polytechnic Institute. All rights reserved. 19 20. Application efficacyLighting Objective Illuminating the picture on the wallApplication lumens: Total lumens reaching a picture areaWasted lumens: Lumens beyond the area of the picture Wasted lumensApplication lumens 2009 Rensselaer Polytechnic Institute. All rights reserved. 20 21. Application efficacyIn this example, compared to sample 1, sample 3 isdesigned better to direct the exiting lumens to the areawhere it is needed.6050Efficacy (lm/W)40-12%30+32%20100 HalogenF8T5 F8T5LEDLED sample 1 sample 2 Sample 3 Sample 4Application Efficacy (lm/W)(Fixture + Driver) Efficacy (lm/W) 2009 Rensselaer Polytechnic Institute. All rights reserved. 21 22. Application efficacyNot switching off the light at the right time wastes energy. 2009 Rensselaer Polytechnic Institute. All rights reserved.22 23. Environmental considerationsMercury An essential component of many energy-efficient light bulbs. Throwing these lamps into the garbage, which ultimately end up in landfills, can pollute the environment. http://www.epa.gov/mercury/about.htmwww.ci.st-joseph.mo.us/publicworks/CFL_Ad.jpgHealth Effects Mercury exposure at high levels can harm the brain, heart, kidneys, lungs, and immune system of people of all ages. http://www.epa.gov/mercury/about.htmLamp Disposal Programs that promote energy-efficient technologies must also consider proper disposal programs.http://blog.lib.umn.edu/scha1028/architecture/htdocs/blog/scha1028/architecture/Lo-Landfill.jpg 2009 Rensselaer Polytechnic Institute. All rights reserved.23 23 24. Selecting Technologiesfor Energy-efficient Lighting Application 2009 Rensselaer Polytechnic Institute. All rights reserved. 24 25. Lamps for residential applicationsToday, linear and compactfluorescent lamps can be used inhouses to conserve energy andreduce nighttime power demand. A variety of CCTs available for the different applications 2009 Rensselaer Polytechnic Institute. All rights reserved. 25 25 26. Lamps for residential applications LFLsCFLsLFLs CFLsLFLs CFLs 2009 Rensselaer Polytechnic Institute. All rights reserved.26 26 27. Lamps for commercial applicationsLFL and CFL can be used in offices,shops, and hotels to conserve energyand reduce power demand.Cool-white and warm-white optionsCan use controls (occupancy anddaylight) to save additional energyDimming is an option, however it couldshorten life 2009 Rensselaer Polytechnic Institute. All rights reserved.27 27 28. Lamps for commercial applicationsIncandescent / halogen PAR and MRlamps are the most commonly usedlamps in shops and hotels GE LightingCFL and ceramic metal halide (MH)reflector lamps are beginning to servethese applications to reduce energy,especially in accent lighting Philips Lightingapplications.However, dimming CFL and MH couldbe difficult GE LightingGE Lighting 2009 Rensselaer Polytechnic Institute. All rights reserved.2828 29. Lamps for industrial applicationsLinear and high-wattage compactfluorescent lamps, and HID lamps can beused in industrial lighting applications. High efficacy 70-95 lm/W Color rendering index >80 Can use controls (occupancy and daylight) to save additional energy 2009 Rensselaer Polytechnic Institute. All rights reserved.29 29 30. Lamps for roadway applicationsHPS, HID, CFL, and LFL lamps can beused in roadway applications to saveenergy and reduce power demand.During nighttime conditions we arewww.westberks.gov.ukmore sensitive to light of a higher colortemperature.Mesopic visionwww.osram-os.com/.../_img/CEC_Street_Lamp.jSeveral studies have demonstrated the pgbenefits of mesopic street lightingObservers perceptions of visibility, HPSCFL, LFL, MH, or LEDsafety, brightness and color2100 K >4000 Krendering are more positive withmesopically tuned lighting.A 30% reduction in power ispossible while maintaining visualperformance. 2009 Rensselaer Polytechnic Institute. All rights reserved. 30 30 31. Emerging Technology 2009 Rensselaer Polytechnic Institute. All rights reserved. 31 32. Rapidly emerging light sourcesNow, solid-state light (SSL) sourcesLEDs andOLEDsare evolving to displace some of thetraditional light sources in some applications. Light-Emitting Diode (LED)LumiLeds OSRAM Opto Cree Light-Emitting Polymer (LEP)Organic Light Emitting Diode (OLED)Universal-displayUniversal- 2009 Rensselaer Polytechnic Institute. All rights reserved. 32 33. What is an LED?Semiconductor p-n junction Light JunctionP-type (depletion region)n-type++ + + - - - -++ -Holes + ++-- Electrons+ + Light ++- - + - - - - Electrons LumiLeds OSRAM 2009 Rensselaer Polytechnic Institute. All rights reserved. 33 34. Colored LEDs All colors within the visible range.However, efficiency is notequal at all wavelengths.1.00.80.60.40.20.0400 450 500 550 600650 700750 Wavelength (nm)450 530 590 650nmnmnmnm 2009 Rensselaer Polytechnic Institute. All rights reserved. 34 35. Creating white light with LEDsMixing different colored LEDs (red, green, and blue)in the right proportions produces white light. RGB LED Systems 2009 Rensselaer Polytechnic Institute. All rights reserved.35 36. Creating white light with LEDsCombining blue or UV LEDs with phosphors produces whitelight. Phosphor-converted White (PC-white) www.olympusmicro.com/primer/java/leds/basicoperation/ledmuseum.candlepower.us/ninth/tf6led1.gifwww.emsd.gov.hk/emsd/images/pee/image1.jpg 2009 Rensselaer Polytechnic Institute. All rights reserved. 36 37. Projected efficacySSL sources hold the promise to reduce electricenergy use by 50% 250 200 Efficacy (lm/W) Projected for SSL 150 100 Fluorescent 50 Incandescent01990 20002010 2020 Year 2009 Rensselaer Polytechnic Institute. All rights reserved. 37 38. National programs around the worldIn 1998, Japan initiated the first national program to catalyze SSLtechnology.The Japan Research and Development Center of Metals established thefive-year national project "Light for the 21st Century".In early 2000, USA initiated a national program in SSL.Congressional Appropriation for SSL Portfolio, 2003-2009 US DOE Program Mission: Guided by a Government-industry partnership, the mission is to create a new, U.S.-led market for high-efficiency, general illumination products through the advancement of semiconductor technologies, to save energy, reduce costs and enhance the quality of the lighted environment.In mid 2000, China started their national program in SSL.$350M RMB($70M USD) was invested from the Ministry of Science andTechnology to support the development of solid-state lighting. The five-yearprogram is lead by Ms. Wu Ling.Several other countries have initiated national SSL programs to catalyzeenergy efficiency in lighting. 2009 Rensselaer Polytechnic Institute. All rights reserved.3838 39. Commercial white LEDsCool WhiteWarm White 100100 XRE (Q5)90 90 Z-Power P480 80Rebel Rigel70 Z-Power P770 XRE (P3)Luminous efficacy (lm/W) Luminous efficacy (lm/W)Golden DRAGON60 Acriche 60Rigel Moonstone Z-Power P4 Vio Vio50Ostar50 DiamondLuxeon K2Rebel Acriche DRAGONGolden40Titan40 DRAGONLuxeon IMoonstone PlatinumPlatinum DRAGON Ostar30DRAGON 30 Luxeon K2OstarLuxeon ITitan20 20 Luxeon K2 Luxeon III10 10 00 0 200400 600 800 10000200400600 800 1000Luminous flux (lm)Luminous flux (lm) 2009 Rensselaer Polytechnic Institute. All rights reserved.39 40. LED applicationsMid-2000Early 2000 to mid-2000www.lumileds.com/gallery/www.ledeffects.com/Late 1990s to early 2000 2009 Rensselaer Polytechnic Institute. All rights reserved.40 41. Festival lightingPower demand increasesduring festivals wherelights are usedColored lightsLEDs can reduce load andsave energy 2009 Rensselaer Polytechnic Institute. All rights reserved.41 42. Present trendsOutdoor Street and Area LightingLED streetlights to take over downtown Ann Arbor 17 Oct. 2007 Ann Arbor plans to become the first U.S. city to convert 100 percent of its downtown streetlights to LED technology, with the installationwww.treehugger.com/files/2008/0of more than 1,000 LED fixtures.7/led-streetlights-anchorage-alaska-16000.phpOSRAM Opto Semiconductorstoday announced that its GoldenDRAGON LEDs are lighting up amajor thoroughfare of Jing JiangCity in the Jiangsu province ofChina. The 180W prototype LEDstreetlights were installed byJiangsu Hua Jing Photoelectronicsfor replacing traditional 250W HIDlamps.http://ecoworldly.com/2008/10/17/intelligent-flowery- street-lights-that-smell-humans-unveiled/ GE Luminations outdoor LED area lightAccording to the article, it saves up to 60 percent energy, longer life, and significantly improved light-level uniformity compared with traditional HID lamp sources andoptical systems, such as a standard 400- www.ledjournal.com/.../june/ GE_outdoor%20LED.jpg watt quartz metal halide system 2009 Rensselaer Polytechnic Institute. All rights reserved.42 43. Present trendsReplacement Lamps & Light Engines Philips-Master LED BulbFigures from: Progress Lighting Figures from Prescolite 2009 Rensselaer Polytechnic Institute. All rights reserved. 43 44. Present trends DownlightingLightoliers ColorWash Sharp Corporation will introduceinto the Japanese market six newLED Downlight Lightings,including three that deliver a lightintensity equivalent to a 150-wattincandescent lamp, an industry first for downlight models. 2009 Rensselaer Polytechnic Institute. All rights reserved. 44 45. General illuminationFrom the Press:Over 4,200 recessed LED lights to be installed in the Pentagon.Recessed LED lights to save over 22 percent energy compared withfluorescent lights, and save 140 tons of carbon dioxide emissions peryear. Cree LR24 Before: A Pentagon room before Crees LED lights were installed. After: The same room at the Pentagon after Crees LED lights were installed (Credit: Cree) (Credit: Cree) 2009 Rensselaer Polytechnic Institute. All rights reserved.45 46. Lighting rural homesKerosene lamps are the predominantsource for lighting in many rural homes Expensive Hazardous Poor quality lightingrolexawards.com/.../02_RAE98WG019.jpg www.wordjourney.com/images/kerosene-lamp.jpg www.designthatmatters.org/k2/pictures/IMG_N29Affordable battery powered LED, LFL, or CFLlamps can be effective in providing lightingsolutions to rural homesDavid Irvine-Halliday, founder of the Light Up TheWorld Foundation (Calgary, Alberta, Canada) 2009 Rensselaer Polytechnic Institute. All rights reserved. 46 47. Lighting transformationLEDs are providing new life to oldsystems www.backcountry.com/store/CMN0105/Coleman-8D-... www.stuga-cabana.com/petromax.gif www.wordjourney.com/images/kerosene-lamp.jpg www.allproducts.com/.../torches/product5-s.jpgwww.giftsscentfromheaven.com.au/shop/images/l... www.shoppingmallsonline.org/uploads/ images/be 2009 Rensselaer Polytechnic Institute. All rights reserved. 47 48. LED lighting systems performance(2009)At best, LEDs have 60% 250system efficiency.Performance (lm/W) 200White LEDEven though the bestLEDs can have 100 lm/W,R&D Resultslighting systems will be at15060 lm/W. 100 Linear Fluorescent Systems Majority of commercial50CFL SystemsLED products have LED SystemsIncand. Systemsefficacies in the range of 10 0to 30 lm/W.20002004 20082012Year www.hrg-ledlighting.com/ProductPicture-china/... deals2give.com/.../uploads/2007/07/ www.global-b2b-p13112a.jpgwww.blogcdn.com/.../2007/02/led-light-bulb.jpg network.com/.../LED_Light.jpg 2009 Rensselaer Polytechnic Institute. All rights reserved. 48 49. LED life Reliability is still a concernHigh Power LEDs100%Buyer bewareRelative light output90%80%70%100%60%50% LRC Data 2004Light Output 100 1000 Hours 10000 100000 90%White Red Blue GreenIncreasing heat 80% 70%010000 2000030000 40000Hours 2009 Rensselaer Polytechnic Institute. All rights reserved.49 50. Over-promised products TaipeiLong life is not a guarantee. System integration greatly determines the life of the product. 2009 Rensselaer Polytechnic Institute. All rights reserved.50 51. LED system lifeFixture B - 26W LED Downlight110%100%Both systems were rated atRelative Light Output90% 40,000 hrs, life80%70%Fixture C - 12W LED Downlight 110%60% 100% Relative Light Output50% 100 1,000 10,00090% Time (hours) 80% Enclosed Semi-ventilated Open air 70% 60% 50%100 1,00010,000Time (hours)Enclosed Semi-ventilatedOpen air 2009 Rensselaer Polytechnic Institute. All rights reserved. 51 52. Final thoughtsSelecting a product for an applicationcan be challenging.Performance varies significantlyLook for independent laboratory testreports.http://www.lrc.rpi.edu/programs/NLPIP/about.aspwww.ci.berkeley.ca.us/.../lightbulbs2.jpg www.nesllc.com/images/Compact-Array.gif 2009 Rensselaer Polytechnic Institute. All rights reserved.52 53. Final thoughtsIt is not about the technology. it is about the productand the application. Within the same technology the product performance varies significantly Same product in different applications performs differently 2009 Rensselaer Polytechnic Institute. All rights reserved. 53 54. Thank you 7W 12W40W LEDCFLIncandescentTechnology on the move 2009 Rensselaer Polytechnic Institute. All rights reserved. 54