Innovations in Solid State Lighting (LEDs)

Transcription

1 Innovations in Solid State Lighting () Allen M. Weiss, PE, LC SESCO Lighting 1133 W. Morse Blvd. Winter Park Florida T: F:

2 SESCO Lighting is a registered Provider with The American Institute of Architects Continuing Education Systems. Credit earned on completion of this program will be reported to CES records for AIA members. Certificates of Completion for non-aia are available on request. This program is registered with the AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation. 2

3 SESCO Lighting is a registered Provider with DBPR, the Florida Department of Business and Professional Regulations. Continuing Education Credit earned on completion of this program will be reported to DBPR records for Registered Professional Engineers, Registered Landscape Architects, Registered Architects, Registered Interior Designers, and licensed General and Electrical Contractors. Certificates of Completion will be provided for all in attendance for the entire seminar. This program is registered with DBPR for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the DBPR of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation. 3

4 Sesco Lighting Innovations in Solid State Lighting [1] [ID # ]

5 Allen M. Weiss P.E, LC is approved and authorized as a Continuing Education Provider by the Florida Board of Professional Engineers (# ), offering Area of Practice courses. In addition, Mr. Weiss is an employee of the Sesco Lighting Company and is offering this lecture to both the attendees and to Sesco Lighting on a Pro-Bono basis. Every attempt has been made to keep this lecture completely generic. At no time during this lecture will products represented by Sesco Lighting be discussed, either by manufacturer s name, product name or product part number. 5

6 Attendees will; Learning Objectives Review and analyze the methods by which light is created, and how solid state devices create light. Compare and quantify the advantages and disadvantages of the various LED types. Investigate and apply current lighting practices regarding lighting equipment, design strategies and energy considerations for solid state lighting. Identify, compare and analyze the reasons to consider the use of light emitting diodes in the application of architectural lighting. Learn and evaluate the advantages and disadvantages of the three currently available LED types. 6

7 Today, with advances in lumen output, optical control, thermal management systems, and robust fixture design, the LED is ready to compete with the HID for general outdoor illumination applications. 7

8 Top View LED Good for wide and slim applications (ex: automotive field) Types of Side View LED Good for small applications (ex: cell phone s on light) Chip LED Good for small, thin applications (ex: mobile phone keypad, site lighting) Lamp LED Good for outdoor or indoor applications (ex: MR16 downlights, street lights) High Flux LED Known for its brightness (ex: exterior signage, task lighting) Dot Matrix LED Used in notice boards or billboards 8

9 History of The first-ever report of light emission from a semiconductor was by the British radio engineer Henry Joseph Round, who noted a yellowish glow emanating from silicon carbide in However, the first devices at all similar to today s arrived only in the 1950s, at Signal Corps Engineering Laboratories, at Fort Monmouth, in New Jersey. Researchers there fabricated orange-emitting devices. In 1962 the first red LED was developed by Nick Holonyak at GE. Throughout the 1960 s, red were used for small indicator lights on electronic devices. Green and yellow were introduced in 1970, these were used in watches, calculators, traffic signs and exit signs. By 1990, of 1 lumen output were available in red, yellow and green. 9

10 History of In 1993, Shuji Nakamura, an engineer at Nichia, created the first high-brightness blue LED. Because red, blue and green are the three primary colors of light, could now produce virtually any color, including white. Phosphor white that combine a blue or UV LED with a phosphor coating to produce white light first appeared in By the late 1990 s began replacing incandescent sources in applications calling for colored light. Between 2000 and today, reached levels of output of 100 initial lumens and higher. White light became available in various shades of light to match the warmth or coolness of incandescents, fluorescents, or daylight. began competing with conventional light sources, and found their way into stage and entertainment applications. Today, represent viable sources for general illumination in many applications. 10

11 What is Light? Lighting 101 The 4 steps to creating light: 1. Excitement an atom absorbs energy 2. Jump electrons are forced to a higher orbit in an unsteady state 3. Fall the electrons fall back to their steady state orbit & release energy 4. Release the energy released is a photon * * The wavelength (color of the light photon) is dependent on the distance the electron has to fall, from a higher orbit, back down to its steady state orbit. 11

12 What is Solid State Lighting? Lighting applications that use light-emitting diodes (), organic lightemitting diodes (O), or light-emitting polymers are commonly referred to as solid-state lighting. The term solid-state refers to the fact that the light in an LED is emitted from a solid object a semiconductor rather than a filament in the case of an incandescent lamp or an expanded gas in the case of a fluorescent or HID lamp. The LED is based on the semiconductor diode. When a diode is switched on electrons are able to recombine with holes within the device, releasing energy in the form of photons. The effect is called electroluminescence. This new technology has the potential to far exceed the energy efficiencies of most other known light sources. 12

13 What is a Semiconductor? A semiconductor is a substance whose electrical conductivity can be altered through variations in temperature, applied fields, concentration of impurities, etc. The most common elemental (pure undoped) semiconductor is silicon, which is used predominantly for electronic applications (where electrical currents and voltages are the main inputs and outputs). Other elemental semiconductors include Carbon and Germanium. An optoelectronic application is when light is the output. In order to create light, other semiconductors material (dopants) must be used. Two examples are indium gallium phosphide (InGaP), which emits amber and red light, and indium gallium nitride (InGaN), which emits near-uv, blue and green light. 13

14 What is a Diode? A diode is a semiconductor made up of two dissimilar materials, an N-Type and P-Type, bonded together. N-Type: A semiconductor that has been doped with extra negative electrons. Dopants might include Nitrogen, Phosphorus, Arsenic or Antimony. P-Type: A semiconductor that has electron holes. Dopents might include Boron, Aluminum, Gallium or Indium. In a diode, current can only flow in one direction. When a DC voltage is applied, the electrons are forced to flow across a junction called the depletion zone and the interaction of the electrons ( falling into ) recombining with the holes creates light! The distance the electron falls determines the wavelength and therefore, the color of the light. (4 steps to creating light Excitement, Jump, Fall, Release) 14

15 What is a Light Emitting Diode? A light emitting diode (LED) is a semiconductor diode that emits light of one or more wavelengths (colors). The two basic types of are indicator type and Illuminator type. Indicator type are usually inexpensive, low power suitable for use only as indicator lights in panel displays, electronic devices or instrument illumination. Illuminator type (high brightness) are durable high power devices capable of providing functional illumination. All illuminator share the same basic structure. They consist of a semiconductor chip or dye (< 1mm² in area), a substrate that supports the die, contacts to apply power, bond wire to connect the contacts to the die, a heat sink, lens and outer casing. Illuminator are packaged in surface mount solder connections, and provide a thermally conductive path for extracting heat. This path is critical for proper thermal management and operation of the LED. Indicator-Type LED Illuminator - Type LED 15

16 How produce white light By itself, an LED can emit only the one color that the specific composition of its materials can produce. The real magic happens when of different colors are combined. According to the RGB (additive) color model, white light is produced by the proper mixture of red, green, and blue light. Methods to generate white light using can be broadly classified into two approaches. 1. Wavelength Conversion (phosphor white) 2. Color Mixing (RGB) 16

17 White Light Wavelength Conversion In a typical phosphor white manufacturing process, a phosphor coating is deposited on the LED die. The exact shade or color temperature of white light produced by the LED is determined by the dominant wavelength of the blue or ultra-violet LED and the composition of the phosphor (s). The thickness of the phosphor coating produces variations in the color temperature of the LED. Phosphor white offers much better color rendering (CRI) than RGB white, often on a par with fluorescent sources. Phosphor white is also much more efficient than RGB white. Because of its superior efficiency and CRI, phosphor white is the most commonly used method of producing white light with. 17

18 White Light Wavelength Conversion Blue LED + yellow phosphor (the least expensive of today s methods). Some of the blue light from an LED is used to excite a phosphor which re-emits yellow light. The yellow light mixes with some of the blue light leaking through, resulting in the appearance of white light. Blue LED + several phosphors Similar to the above method, except that the blue light excites several phosphors, each of which emits a different color. These different colors are mixed with some of the blue light leaking through, to make a white light with a broader, richer wavelength spectrum. This gives a higher colorquality light than the above method, albeit at a slightly higher cost. Ultraviolet (UV) + red, green and blue phosphors The UV light from an LED is used to excite several phosphors, each of which emits a different color. These different colors mix to make a white light with the broadest and richest wavelength spectrum. This gives the highest color-quality light, again albeit at a slightly higher cost. 18

19 Color Mixing White Light Color Mixing This method uses multiple in a single lamp, and mixes the light to produce white light. Typically, the lamp contains at least two (blue and yellow) and sometimes three (red, blue, and green) or four (red, blue, green and yellow). RGB white gives control over the exact color of the light, and it tends to make colors pop. But RGB white is hardware intensive since it requires multiple to produce white light. Also, it tends to render pastel colors unnaturally, a fact which is largely responsible for the poor CRI of RGB white light. Tunable white light fixtures adapt the mixing principles of tricolor LED devices to produce white light in an adjustable range of color temperatures. Tunable white light devices typically combine cool and warm white, which can be individually controlled like red, green and blue in a full color LED device. Adjusting the relative intensities of the warm and cool changes the color temperature just as adjusting the relative intensities of the red, green and blue changes the color in a full color device. 19

20 Color Rendering Index & RGB According to the U.S. Department of Energy The color rendering index (CRI) has been used to compare fluorescent and HID lamps for over 40 years, but the International Commission on Illumination (CIE) recently announced that it does not recommend its use with white! Why?... CRI is a measure of how well light sources render the colors of objects, materials and skin tones. The test procedure for CRI involved comparing (8) color samples under the light in question and a reference light source of the same color temperature. The Problem Due to the RGB spikiness it scores low on CRI, but is usually very visually appealing. 20

21 Chip LED Optics Conventional HID Systems Bare HID lamp: - Omni-directional - Needs reflector to re-direct light to create different distributions - Not uniform (significant uncontrolled lights is emitted from luminaire) Packaged LED System Chip LED: - Uniformly distributed (forward only) - Distribution < Secondary optics (refractors) can be added for precise beam control - Refractors are more efficient than reflectors 21

22 Chip LED Optics Bare LED - No Optics With Optics Precise Beam Control 22

23 Chip LED Optics for Roadways 23

24 LED Vs. HID Lumen Maintenance average delivered lumens are 46% higher than HIDs over 60,000 hours. 24

25 LED Vs. HID Lumen Maintenance Where do the lumens go?... HID system LED system Note * Therefore, LLF (Light Loss Factors) for LED photometric calculations can be significantly higher than LLF used in Metal Halide or High Pressure Sodium applications. 25

26 LED Progress The development of LED technology has caused their efficiency and light output to increase exponentially, with a doubling occurring about every 36 months since the 1960s. In 2000, the LED ranged around 50 lm/w. By 2010 most major manufacturers of are producing 6000K around 100 lm/w that deliver lm/w in the field depending on fixture efficiency. (Warmer are slightly less efficacious). Initial Lumens 2010 Remember These # s are initial lumens not maintained lumens. 26

27 SSL Research & Development: Multi-Year Program Plan Summary of LED Luminaire Price and Performance Projections (DOE) METRIC Package Efficacy (lm/w, 25C) Commercial Cool White Thermal Efficiency 87% 89% 92% 95% 98% Efficiency of Driver 86% 87% 89% 92% 96% Efficiency of Fixture 81% 83% 87% 91% 96% Resultant Luminaire Efficiency Luminaire Efficacy (lm/w) Commercial Cool White 61% 64% 71% 80% 90% METRIC Cool White Efficacy (lm/w) Cool White Price ($/klm) Warm White Efficacy (lm/w) Warm White Price ($/klm)

28 General Design Factors No matter what you re individual opinion is (for or against ), there are decision factors that all lighting designers, architects, specifiers, etc.. must consider. The basics of the specification decision are: Efficiency: Once lower on the list simply because the lumens per watt were not there, now a top reason for considering LED. (especially for colors = no filters needed) Performance: At the very least, must match the performance of current HID luminaires, but it s becoming obvious, that they are outperforming HID in light output, lumen maintenance, light control and distribution, uniformity, color, and reduced glare. Longevity: A quality LED fixture will give you long life (50k+ hrs) without sacrificing efficiency and performance (unlike fluorescents and HIDs) 28

29 Advantages of Small (small lamp = small fixtures, good for designers + better optical control) Instant on, Quick to reach full brightness (microseconds). No re-strike issues Cool to the touch (Low wattage) Tunable (Various color temperatures and CRI s available) On/Off constant cycling does not effect lamp life (good with occupancy sensors) Little forward heat (good for lighting precious objects) No UV available No Mercury (RoHS compliant, many are lead-free as well) One LED failure does not make others in same lamp fail Does not require filters to create color The LED package can be designed to focus light, without the need of an external reflector Resistant to external shock (good for shipping & places with constant vibration, like a parking garage) Long life (35-50,000 hrs for white, 100,000 hrs for red) less environmental waste Fail by dimming over time (not abruptly like other lamps) Excellent lumen maintenance (very little degradation LLFs >.90) Full cutoff is available Recent enforcement of testing standards to enable meaningful product comparisons 29

30 Disadvantages of Minor Disadvantages: Expensive initial cost (but better life-cycle cost) Performance largely depends on ambient temperature & heat-sinking (you can t just stick an LED in a regular fixture housing) Must be supplied with the correct current (needs a power supply/driver to convert AC to DC) Because of their long life, they may not undergo the routine cleaning every 3-5 years typically corresponding with re-lamping. Major Concerns: False claims and misinformation from manufacturers Technology is changing DAILY! 30

31 Droop & Green Gap: the mysterious maladies Although LED internal quantum efficiencies initially tend to rise with increasing current densities, they subsequently level off and then drop as the operating current increases. This roll-over and the droop that follows it are major obstacles to the development of high-efficiency, high brightness for low-cost SSL. Unfortunately, while droop isn t such a problem for near-uv devices, it becomes increasingly important for longer-wavelength blue and green emitters, which contain high proportions of indium in the indium gallium nitride (InGaN) active regions of the device. This increase in indium content tends to be correlated with drastic reductions in device efficiencies even at the optimum operating current, limiting device performance as emission wavelengths move into the green and yellow spectral regions. Coming from the other end of the spectrum, the efficiencies of aluminum indium gallium phosphide (AlInGaP) devices - traditionally used to create red, yellow and orange emitters - also falls off as wavelengths shorten and move towards the green, hence the term green gap. 31

32 What to look for? : The first key component to an LED system is the right LED. Different have different efficacies. The next challenge is to maintain the efficacy of the LED as additional components are added to the system. Things to look for in a LED include: High brightness Super-white High Lumen/Watt ratio (efficacy) Long Life 32

33 What to look for? Drivers: Similar to Low Voltage Halogens, Fluorescents, & HIDs, require a power source. The LED driver converts line voltage (AC) into operating voltage (DC). will only be as good as the drivers which operate them. Things to look for in a driver include: 90 93% efficient A life that matches the paired with them Electronic Driver output frequency at least 120 HZ 12 bit or greater resolution for flicker free operation Auto sensing 50/60 HZ, universal voltage Dimming capability-driver and Dimmer must be matched High power factor Potted in a wet listed housing compartment Warranty 33

34 What to look for? Thermal Management System: Temperature DOES affect LED s. Although LED performance has improved tremendously over the past 10 years, thermal management remains a major concern for manufacturers and end users alike. operate most efficiently when cool. When electrical current is not converted into light, it is converted into heat. The higher the junction temperature, the lower the lumen output. Things to look for in a TMS include: Robust Heat Sink provides cool junction temperatures & proper dissipation of heat via the submount & substrate, out through the fixture Cool ambient temperatures - proper method to dissipate heat out of the fixture 34

35 What to look for? Dimming Capability : face a dimming challenge similar to that of CFLs: Their electronics are often incompatible with dimmers designed for incandescents. An LED driver connected directly to a line voltage incandescent dimmer may not receive enough power to operate at lower dimming levels or it may be damaged by current spikes. More sophisticated LED dimmers use low voltage controls connected separately to the driver. Full power is provided to the driver enabling the electronic controls to operate at all times, thus allowing to be uniformly dimmed (5% or lower). Most white are actually blue with a phosphor coating that generates warm or cool white light. Their light does not shift to red when dimmed; some may actually appear bluer with dimming. White light can be made with RGB, allowing a full range of color mixing and color temperature adjustment. Overall LED efficacy decreases with dimming due to reduced driver efficiency at low dimming levels. 35

36 What to look for? Housings: Since an LED lighting system is designed to last 50k-100k hrs (approx hrs./day), you need superior fixture design. Things to look for in a housing: Durability (Low copper content, die-cast aluminum, long lasting finish, minimum of an IP66 rating) Functionality (Heat dissipation-perforation or fins) Style (Modern will be around in 20 years!) Cleaning & Pre-treatment Epoxy e-coat Colorfast Powdercoat 36

37 Testing Standards IESNA -LM-79: Approved Method for testing the Electrical and Photometric Measurements of Solid-State Lighting Products - How to measure Lumens, Efficacy (Lumens/Watt) IESNA- LM-80 Approved Method for Measuring Lumen Depreciation of LED light Sources -LED lamp life (L70) occurs when lumens depreciate 30% NEMA /ANSI -ANSLG C : Specifications for the Chromaticity of Solid-State Lighting Products for Electric Lamps - How to determine CRI for wavelength conversion white 37

38 Testing Standards -CALiPER -The DOE Commercially Available LED Product Evaluation and Reporting (CALiPER) program supports testing of a wide array of SSL products available for general illumination. DOE allows its test results to be distributed in the public interest for noncommercial, educational purposes only. Detailed test reports are provided to users who provide their name, affiliation, and confirmation of agreement to abide by DOE's NO COMMERCIAL USE POLICY. 38

39 & LEED USGBC s LEED-Green Building Design & Construction-2009 Four Levels of Certification Available (Certified, Silver, Gold, Platinum) Holistic Approach to Building Design No One Product, Technology or Process will ensure LEED Certification BUT: Individual Products can contribute significantly to earning LEED credits Relevant Credits that can utilize : Energy & Atmosphere Prerequisite 2 - Minimum Energy Performance Energy & Atmosphere Credit 1 Optimize Energy Performance (2-10pts) Environmental Quality Credit 6.1 Controllability of Systems: Lighting (1pt.) Sustainable Site Credit 8 Light Pollution Reduction (1 pt.) Innovative Design Credit 1 (ex: low mercury content in lamps) (1pt.) 39

40 Cost of HID vs. Life Cycle Costing vs. Traditional Initial Cost Analysis HID LED * Overall size of LED pie is smaller 40

41 To Think About Does the fixture utilize from a reputable LED manufacturer? Is the manufacturer quoting initial or delivered LED lumens? (is efficacy based upon testing the entire luminaire -, drivers, heat sinks, optical lenses and housing) Is the manufacturer quoting individual LED lamp life, or actual LED-fixturesystem lamp life? Does the fixture manufacturer utilize the new testing standards for quoting their product information (lumens, lamp life, CRI) How is the fixture designed to dissipate heat away from the? How well is the driver made, does it meet all your needs for the project? (PF >90%, THD <20%) Does the fixture utilize built-in LED optics to make it more efficient or does it depends on a less-efficient reflector? 41

42 To Think About Does the fixture (-Driver combination) come with a reasonable warranty that is similar to the life of the? Is the housing robust? (how well is it made, is it designed to last the life of the, IP66+, RoHS compliant (no lead, mercury, etc.) Does the fixture have various glare control and/or cut-off characteristics that suit your projects needs? (limit light pollution-light tresspass, sky glow & glare) How long will the manufacturer guarantee to be making or stock the product? (in case a replacement is needed in the future) What needs to be replaced when something burns out? (The whole fixture, or a portion of the fixture?) What are your maintenance costs? (changing lamps, ballasts, fixtures, etc.) Is initial cost or long-term energy cost the primary concern for the owner? 42

43 Real World Examples (Exterior) Before (HPS) After (LED) Before (Fluorescent) After (LED) 43

44 Real World Examples (Color Changing) Hollywood Casino 44

45 Real World Examples (Color Changing) Morimoto Restaurant Marriott Marquis Pfizer s Training Center Club Goddess 45

46 Real World Examples (Interior) Downlights: Cove Lights: Track Lights: Under Cabinet & Task Lights: Pendants & Sconces: 46

47 Real World Examples (Exterior) Water Features: Path/Marker: 47

48 Real World Examples (Exterior) Signs: Architecture: 48

49 Real World Examples (Exterior) Landscape: 49

50 Bibliography Beta LED LED Lighting Simplified-Philips-Color Kinetics ( Cree Lighting ( The Lighting Research Center at RPI ( Seoul Semiconductor US. Department of Energy Ruudlighting.com 50

51 QUESTIONS? Course Title: Innovations in Solid State Lighting () SESCO Lecture # 1 Provider: Allen Weiss Instructors: Allen Weiss / Fred Butler AIA/CES Provider # / Course #: L140 / 00SES1 FL DBPR-Architect & Interior Designer Provider # / Course #: / FL DBPR-Landscape Architect Provider # / Course #: / FL DBPR-Electrical Contractor Provider # / Course #: / FL DBPR-General Contractor Provider # / Course #: / IDCEC (ASID, IIDA) Course #: 7795 FBPE Provider # / Course #: / USGBC/GBCI/LEED Course #: SESCO Lighting 1133 W. Morse Blvd. Suite 100 Winter Park Florida This concludes the American Institute of Architects, GBCI s & DBPR s Continuing Education Systems Programs 51