LED Terminology, Technology and Application Robert Ebbert, LC © 2015 Eaton, All Rights Reserved. A History of Light Sources • • • • • • • • • • • • • ~400,000 BCE - Fire is discovered. ~3000 BCE - Oil lamps are open bowls with a spout to hold the wick. ~400 - The candle is invented. 1809 - Sir Humphrey Davey demonstrates electrical discharge lighting to the Royal Institution in London, using an open-air arc between two carbon rods. The result is a very intense, and very pure white light. Unfortunately, as the arc runs, carbon boils off and the rods wear away: constant attention must be paid to readjusting the arc, feeding more carbon in. 1841 - Frederick DeMoleyns patented incandescent lamp using filaments of platinum and carbon, protected by a vacuum. 1880 - Thomas Edison receives U.S. patent #223,898 for the carbon filament incandescent lamp. 1932 - Low pressure sodium lamps are first used commercially. 1934 - The high-pressure mercury lamp is introduced. 1938 - First commercial sale of the fluorescent lamp 1957 - The quartz halogen lamp (A.K.A. tungsten halogen lamp) is invented. In conventional tungsten lamps, the filament metal slowly evaporates and condenses on the glass envelope, leaving a black stain. In this case, the halogen removes the deposited tungsten and puts it back on the filament. 1962 - First light emitting diode (LED) 1966 - Commercial introduction of the high pressure sodium lamp 1969 - A new form of metal halide lamp, the HMI lamp (mercury medium arc iodides) is introduced. The H stands for mercury (atomic symbol "Hg"), M is for Metals and the I is for halogen components (iodide, bromide). It provides a daylight type spectrum. © 2015 Eaton, All Rights Reserved. 2 Life Rating of Light Source Note regarding life ratings: • Life for HID is calculated when 50% of lamps are burned out. • Life for LED is calculated via IESNA TM‐21, limits life claim to 6 x the number of hours tested. Typical is 60,000, life is then given as the lumen depreciation estimated at that life number. For example, L9060,000 is 90% lumen depreciation at 60,000 hours. © 2015 Eaton, All Rights Reserved. 3 Overview of Sources BLUE COLOR LIFE: 24,000 RATED 9,600 MEAN EFFICACY: 50~60 LPW CCT: 5700K CRI: 15 WHITE COLOR LIFE: 16,000 RATED 6,400 MEAN EFFICACY: 80~100 LPW CCT: 4000K~5000K CRI: 60~70 YELLOW COLOR LIFE: 24,000 RATED 12,000 MEAN EFFICACY: 100~120 LPW CCT: 2000K CRI: 15~25 WHITE COLOR LIFE: 24,000 RATED 9,600 MEAN EFFICACY: 100~120 LPW CCT: 3500K~4100K CRI: 80~90 © 2015 Eaton, All Rights Reserved. WHITE – ANY COLOR AVAILABLE LIFE: 350,000 RATED 60,000 MEAN EFFICACY: 60~110 LPW CCT: 3000K~6000K CRI: 65~85 PRICE: $-$$$ 4 4 Induction Lighting Opportunities Threats Low price points compared to LED driving "second look“ Additional awareness of maintenance costs 160 $100 •Efficiency 140 $90 $80 120 $70 100 $60 80 $50 60 $40 $30 40 •Cost 20 $20 •Cost ($/kilolumen) •Efficacy (lumens/watt) LED might obsolete $10 $0 0 2007 2012 2017 •Source: DOE Report “Energy Savings Potential of SSL in General Illumination Applications (High CRI)– Dec 2006” Strengths 100,000 Hour Life (50% mortality) Instant Start and Re-Strike System 80-90 Lumens per Watt Excellent Lumen Maintenance 100% Flicker Free Excellent CRI – 80-95 Weaknesses Thermal Management with retrofits Poor or limited optical control due to size of lamp, Generally not dimmable Limited lumen packages Not a strong track record for reliability Requires mercury to operate Light output varies with operating temperature. Low delivered lumens per watt •Interesting technology, but limitations have depressed adoption © 2015 Eaton, All Rights Reserved. 5 LED vs Induction 40’ Grid Right 25’ MH . . Street Street Left 165 watt Induction luminaire (180 total watts)Type 3 Short with 8414 delivered lumens, 47 lumens per watt. Light behind the pole for over 40’. LED with Type 2 optic, 9294 lumens (92 watts), 101 delivered lumens per watt with light evenly dispersed 10’ to 30’ behind the luminaire for sidewalk illumination. © 2015 Eaton, All Rights Reserved. Plasma Lighting Opportunities Threats LED price points forcing examination of alternate technology 160 $100 •Efficiency 140 $90 $80 120 $70 100 $60 80 $50 60 $40 $30 40 •Cost 20 $20 •Cost ($/kilolumen) •Efficacy (lumens/watt) LED might obsolete $10 $0 0 2007 2012 2017 •Source: DOE Report “Energy Savings Potential of SSL in General Illumination Applications (High CRI)– Dec 2006” Strengths Weaknesses Quick Start and Re-Strike Excellent CRI ~ 80 Purported to have Long Life Relatively inefficient source (~50-80 LPW @ Source) Thermal Management with retrofits Lifetimes of electrical components suspect Optical control in Outdoor asymmetric applications a challenge •Interesting Source, but may be too late to Market © 2015 Eaton, All Rights Reserved. 7 LED Luminaire and Component Testing Reliability System Testing • Humidity • Salt Spray • Water IPX6 • Dust IP6X • Vibration testing • UV testing • Thermal testing on luminaires at -30°C (-30°F) degree to 40°C(104°F) standard, -40°C to 50°C for certain models. • Thermal testing on components from -40°C to 90°C • Require UL accredited test laboratory and NVLAP accredited Photometrics laboratory. • DOE approved Lighting Facts Test Laboratory partner © 2015 Eaton, All Rights Reserved. 8 Thermal Test Information At right is a sample thermal test report on an outdoor LED luminaire. Note readings are taken on many parts of the luminaire including the LED case, driver and surge module. © 2015 Eaton, All Rights Reserved. 9 Absolute and Relative Photometry Absolute Photometry LED luminaires LM-79-08 Lamps integral to luminaire No lamp seasoning, calibrated to lamp of known output Actual lumen output measured Unique results for each product Relative Photometry Bare lamps measured separately. • • • Seasoned (aged) lamps Output stabilization Raw output measured Luminaire test • • • Same lamps and ballast Identical electrical and thermal characteristics Results scaled to initial rated lamp lumens Same results with different lamps © 2015 Eaton, All Rights Reserved. 10 Photometric Testing per IES LM-79-08 Electrical and Photometric Measurements of SolidState Lighting Products – Luminaire based absolute photometry • Total Luminous Flux • Luminous Intensity Distribution • Electrical Power • Luminous Efficacy (LPW - calculated) • Color Characteristics • Chromaticity • CCT • CRI Integrating Sphere © 2015 Eaton, All Rights Reserved. 11 Integrating Sphere Report © 2015 Eaton, All Rights Reserved. 12 Quality of Light High Pressure Sodium (2000K) Metal Halide (Quartz, Ceramic, Moonlight) ~4000K COLD LED (6000-6500K) 4000K, 70 CRI is becoming an industry standard for the majority of outdoor applications. © 2015 Eaton, All Rights Reserved. 13 Measuring Luminaire Performance Goniophotometer An apparatus for measuring the directional light distribution characteristics of light sources, luminaires, media, and surfaces. PLAN VIEW Luminaire Indirect Light Shield Photocell Mirror © 2015 Eaton, All Rights Reserved. 14 Absolute IES file information from Goniophotometer © 2015 Eaton, All Rights Reserved. 15 Luminaire Classification System Backlight Up-light Glare 180° UH 100° 100° UL 90° 80° 90° FVH BVH 80° BH FH 60° 60° BM 30° FM BL FL 0° 30° Zonal distribution of the fixture are broken up into 10 distinct sections. Values are often in terms of a percentage of overall lamp lumens. Any one rating is determined by the maximum rating obtained for that table. For example, if the BH zone is rated B1, the BM zone is rated B2, and the BL zone is rated B1, then the backlight rating for the luminaire is B2. © 2015 Eaton, All Rights Reserved. 16 UV stabilizers greatly reduce the rate of yellowing on plastic materials Require UV stabilizers on all optical materials Control UV Treated © 2015 Eaton, All Rights Reserved. 17 Class 2 LED Driver LED luminaires with Class 2 drivers can use an acrylic lens. © 2015 Eaton, All Rights Reserved. 18 Class 1 LED Driver Class 1 LED luminaires will have a glass or polycarbonate lens © 2015 Eaton, All Rights Reserved. 19 Superior thermal management results in long life The above driver data sheet indicates that the driver lifetime is 100,000 hours with a Tcase operating temperature of 75C or lower. The following thermal report had a Tcase temperature of 56°C when operating in a 40°C ambient environment. © 2015 Eaton, All Rights Reserved. 20 Thermal report to confirm driver and LED operating temperature at 40°C ambient The above 40C thermal report shows the driver running at 56C. Per the driver specification sheet on the previous slide the driver should last 100,000 hours at this temperature without a disabling electrical surge. © 2015 Eaton, All Rights Reserved. 21 Surge protection is also essential for driver life • Magnetic ballast designs tend to meet 7 kV or 10kV BIL requirements • not uncommon to see 10kV to 15 kV or more capability • ANSI C82.6 Mandates 10kV for Roadway Application, 6kV for all other Outdoor Applications. • Electronic Drivers tend to meet a 2-4kV BIL • fine for many applications • far more susceptible to lighting strike induced transients than magnetic. ... Unless very specific provisions have been incorporated in their design © 2015 Eaton, All Rights Reserved. 22 Make sure the SPD meets UL1449 © 2015 Eaton, All Rights Reserved. 23 UL1449 Surge Protector Label Deciphered This information is required on the label of a UL 1449 Surge Protective Device Ratings: max nominal voltage, frequency and line current that the product is rated for. These are the nominal operating conditions under which the surge protector will essentially do nothing. ln =3kA: this is the current magnitude used to evaluate the product. Each protection mode (line-neutral, line-ground, neutralground) is surged 15 times at this 3kA current. Type 2 – UL surge protector designation. Type 2 is defined as a permanently connected surge protector installed after the main disconnect or circuit breaker (in other words, installed in the fixture as opposed to on the panel). MLV: Measured Limiting Voltage. This is the voltage measured for each mode (line-neutral, line-ground, neutral-ground) during the 3kA surge tests described above. In other words, this was the voltage needed to drive a 3kA surge for each mode. Essentially it documents what took place during the 3kA surge test. MCOV: Max Continuous Operating Voltage. This is the voltage below which the surge protector doesn’t do anything. It is generally about 15-20% higher than the nominal rated voltage (347V) in order to accommodate small fluctuations in operating voltage. Above MCOV (in this case, 420V), the surge protector starts shunting current across the mode (line-neutral, line-ground, neutral-ground) instead of allowing it into the fixture. Once this starts, the surge protector will begin to suffer damage. Instantaneous spikes do little damage, but sustained over-voltage conditions will cause permanent damage to the surge protector until it fails, at which point the fixture will not operate until the surge protector is replaced. Surge modules available in series or parallel configurations with up to 20kV/20kA protection © 2015 Eaton, All Rights Reserved. 24 Surge Protector – What to Look For Does not display a UL or CSA marking; non-compliance with Article 285.5 Does not describe short circuit current rating; non-compliance with Article 285.6 Does not incorporate fusing such that SPD becomes disconnected after MOV failure; non-compliance with Article 285.27 May not be 14AWG Wires; possible non-compliance with Article 285.26 Insufficient protection will reduce fixture life. © 2015 Eaton, All Rights Reserved. 25 IESNA LM-80 Test Report summary page Luminous flux depreciation information After 10,000 hours of testing this LED has actually increased at the 85°C and 105°C case temperatures with only a .0006 decrease at 55°C case temperature © 2015 Eaton, All Rights Reserved. 26 IESNA LM-80 Test Report summary page Color or kelvin temperature shift information In-situ case operating temperature of 86°C the NVN LED at 25C ambient at 86°C shows minimal color shift over the 10,000 hour test period. © 2015 Eaton, All Rights Reserved. 27 TM-21-11 • LM-80 -- only an LED testing standard • IES TM-21-11 -- mathematical framework for LM-80 data and making useful LED lifetime projections Key points of TM-21: • Developed by major LED suppliers with support of NIST, PNNL • Projection limited to 6x the available LM-80 data set • Projection algorithm: least squares fit to the data set • L70, L80, L90, Lxx projections easily possible • Nomenclature: Lp(Yk)where p is Lumen Maintenance percentage and Y is length of LM-80 data set in thousands of hours ie: L85(10k) © 2015 Eaton, All Rights Reserved. 28 TM-21 – Use the latest data Initial data variability (i.e. “hump”) is difficult for models to evaluate (0-1000 hr) Later data exhibits more characteristic decay curve of interest • Non-chip decay (encapsulant, etc.) occurs early and with varying effects on decay curve • Later decay is chip-driven and relatively consistent with exponential curve • Verification with long duration data sets (>10,000 hr) shows better model to reality fit with last 5,000 hours of 10,000 hour data For 6,000 hours of data (LM-80 minimum) and up to 10,000 hours: Use last 5,000 hours For > 10,000 hours: Use the last ½ of the collected data © 2015 Eaton, All Rights Reserved. 29 Energy Star TM-21 Report Displays lumen maintenance of the LED in the luminaire at a selected ambient temperature over a specific period of time. This TM-21 report shows 95% lumen maintenance at 60,000 hours in a 40C ambient environment with 10,000 hours of LM-80 data. © 2015 Eaton, All Rights Reserved. 30 Drive Current, What is it? LuxeonTX HP MPG Efficacy LPW Drive Current Vf Watts Lumen Output 350mA 2.71V .95 147 155 700mA 2.80V 1.96 269 137 1050mA 2.86V 3.00 360 136 The harder you drive an LED the less efficient it is, but remember the Prius in not necessarily going to “last” longer than the Porsche. 408 HP 17 MPG / 0-60MPH 3.7 sec. 134 HP 50 MPG / 0-60 MPH 11 sec. © 2015 Eaton, All Rights Reserved. 31 Drive current and fixture specification • Each LED package has different maximum current and junction temperature specifications. • The drive current that pushes one past its thermal limits may be well within another’s operating limits. • Managing the thermal load is key to operating an LED within its performance limits. • An LED that is properly heatsinked can withstand higher drive currents. • The key is to draw heat away from the LED junction so that it reaches thermal equilibrium below its max allowable temperature. • Lighting should be specified around the performance needs of the end user (luminance, illuminance, efficacy, etc.), not its internal design. © 2015 Eaton, All Rights Reserved. 32 3 LED Comparison 3.2W 5.8W 61W • The LED on the left is from a Navion. • Voltage = 3V Drive Current = 1.05A, Wattage = 3.2W. • The LED in the middle is from a Caretaker. • Voltage = 145V Drive Current = 0.04A, Wattage = 5.8W • The LED on the right is from a Verdeon. • Voltage = 34V Drive Current = 1.8A, Wattage = 61W Question: Which one is running at the best drive current? © 2015 Eaton, All Rights Reserved. 33 LED Comparison 3.2W 5.8W 61W Answer: Each is running at the correct drive current for its application. • 1-Square Navion • 16 LEDs @ 3.2W each • Total wattage = 51W • Case temperature of LEDs < 85oC, within mfr specs • Caretaker • 8 LEDs @ 5.8W each • Total wattage = 46W • Case temperature of LEDs < 85oC, within mfr specs • Verdeon A01 • 1 LED @ 61W • Total wattage = 61W • Case temperature of LEDs < 100oC, within mfr specs © 2015 Eaton, All Rights Reserved. 34 What Determines Life? Heat = Life An LED driven at 1050mA with a Tc (case temperature) of 85C will outlive the same LED driven at 530mA with a Tc of 90C Life = Tc Drive Current = Efficiency © 2015 Eaton, All Rights Reserved. 35 Why you should not specify by lumens per watt Same source, same ballast, different performance 150 WATTS 150 WATTS 25’ 85 Lumens per Watt 67 Lumens per Watt 0.46 Average Illuminance 0.93 Average Illuminance Why the “lumens per watt method” of calculating lighting fixture performance alone does not equate to energy efficiency. Although the luminaire on the left is 27% higher in fixture LPW, it produces less than half the average illumination on the ground To give the same illumination as the lower LPW fixtures, over twice as many of the higher LPW fixtures would be needed, resulting in a net energy increase of 102% © 2015 Eaton, All Rights Reserved. 36 Where is the light going? Three dimension rendering of light distributions and relative footcandles on ground High LWP post top on left, lower LPW shoebox on right © 2015 Eaton, All Rights Reserved. 37 Luminaire Dirt Depreciation Dirt, dust, dead bugs and water collect inside this HID luminaire lens in Boston, MA How much light is really passing through the lens? © 2015 Eaton, All Rights Reserved. 38 HID │LED LIGHT LOSS FACTORS HID (High Pressure Sodium) vs. LED LED Type 3 distribution HID Type 3 distribution LLF = BF * LDD * LLD Ballast Factor Luminaire Dirt Depreciation 1.0 0.90 Ballast Factor Luminaire Dirt Depreciation 1.0 0.95 (IP66 optical chamber) LLD (Lamp Lumen Depreciation) 0.90 LLD = Mean Lumens (@ 50% of lamp life) / Initial Lumens (12,000 hours) LLF = 0.9 * 0.90 = 0.81 LLD (Lamp Lumen Depreciation) 0.96 LLD = Mean Lumens (@ ~60,000 hrs) / Initial Lumens LLF = 0.95 * 0.96 = 0.91 © 2015 Eaton, All Rights Reserved. 39 39 HID │LED Equivalency HID vs. OVX Type 3 distribution 250W HPS Lamp LED LED Type 3 distribution 28,000 lumens 110 watt LED 10,567 lumens 70% Total Downward Luminaire Efficiency 19,600 lumens 100% Total Downward Luminaire Efficiency 10,567 lumens Street Side Lumens (52.7%) 10,329 lumens (300 ballast watts) X 0.81 LLF = 8,366 lumens Street Side Lumens (82%) X 0.91 LLF 8,660 lumens = 7,880 lumens ~6% less street side lumens after 5X the operating hours © 2015 Eaton, All Rights Reserved. 40 40 300 ballast watts LED type 2 vs HID Flat Glass 250 watt HPS Type 3 cobrahead 24’ roadway, 2’ setback, 25’ mounting height, 4’ sweep arm, 145’ spacing Illuminance Comparison LED • • I I • • Red line = .1 FC 110 watts, 10,308 initial delivered lumens, 8,774 downward street side lumens .912 Light Loss Factor (60,000 hours) 1.61 average, .42 minimum, 3.56 maximum, 3.83 to 1 ave/min. Max Lv Ratio .33 on R3 pavement Green line = .5 FC HID • I I • • When lighting 2 to 3 lane roadways, type 2 distribution patterns will concentrate more light on the roadway than type 3 distribution patterns. © 2015 Eaton, All Rights Reserved. • 300 watts, 22,120 initial delivered lumens, 15,272 downward street side lumens .81 Light Loss Factor (12,000 hours) 2.88 average, .37 minimum, 9.86 maximum, 7.78 to 1 ave/min. Max Lv Ratio .35 on R3 pavement 43 LED Type 2 vs LED type 2 34’ mounting height, 8’ setback with 8’ arms LED Luminaire 1 • • I I • 149’ pole spacing for a 1.01 FC average • • 154 watts, 11,136 initial delivered lumens, 8,733 downward street side lumens .85 Light Loss Factor (60,000 +hrs) 1.01 average, .84 minimum, 1.21 maximum, 1.20 to 1 ave/min. Rear spill light 25’, forward spill light 46’ Max Lv Ratio .26 on R3 pavement LED Luminaire 2 • I I • • 155’ pole spacing for a 1 FC average • LED on top has shorter pole spacing while using more watts due to less light on task (roadway). • © 2015 Eaton, All Rights Reserved. 110 watts, 9,817 initial delivered lumens, 8,356 downward street side lumens .85 Light Loss Factor (60,000+ hrs) 1.0 average, .56 minimum, 1.66 maximum, 1.79 to 1 ave/min. Rear spill light 25’, forward spill light 38’ Max Lv Ratio .23 on R3 pavement 44 Existing Atlanta roadway lighting with 150 HPS drop glass cobra head Would you feel safe walking in this neighborhood at night? 2000K, 20CRI light source with poor optical distribution HID luminaires at the intersection in the foreground are contributing to light level at the bottom of the picture. © 2015 Eaton, All Rights Reserved. 45 Newly installed LED luminaires with over optic lens provides a visibly superior night environment for the residents of this Atlanta neighborhood. 4000K with ~73 CRI with the provides higher luminance levels on the roadway and sidewalks with 51% less energy Luminance = The amount of light reflected off the roadway or sidewalk Verdeon luminaires at the intersection in the foreground are contributing to light level at the bottom of the picture. © 2015 Eaton, All Rights Reserved. 46 External Shields Field installed LED shield © 2015 Eaton, All Rights Reserved. 47 Optical Control Advantage Over External Shields 40’ Grid 25’ MH . . Street Type 2 Short , 7928 lumens, 78 lumens per watt, with light more than 40’ behind the pole. Street . Street Type 2 Short with an external Type 2 Medium internal control shield, 6090 lumens, 60 optics, 7523 lumens, 105 lumens lumens per watt, light per watt with light evenly reduced to 20’ behind the dispersed 10’ to 20’ behind the pole. pole for sidewalk illumination. External shields can reduce luminaire efficiency by as much as 23%. precision optics maintain luminaire efficiency by re-directing the light evenly along the roadway. © 2015 Eaton, All Rights Reserved. 48 The poor optical control of the existing HID shoebox luminaires does a poor job of directing light into the second row of trucks at this auto dealership Superior light control with higher CRI produces better results with less total lumens and watts. Why field rotatable optics on a roadway fixture? Light both roadways and the intersection from a single pole. 50% of optics rotated 90 degrees. 35’ mounting height, 10’ arm. Intersection and over 170’ of roadway illuminated in both directions by a single luminaire using only 110 watts. 26’ Wide Road . Type 2 beam pattern shown with the luminaire delivering ~10,000 total lumens. © 2015 Eaton, All Rights Reserved. 51 New optical technology blocks the line of sight of the LED light source from the observer reducing glare while delivering 90 lumens per watt. © 2015 Eaton, All Rights Reserved. 52 Questions? © 2013 Eaton. All rights reserved. 53