Do s and Don ts of LED Lighting

Transcription

1 Do s and Don ts of LED Lighting

2 Jeff Hakenewerth, LC Industrial Lighting Specialist Lighting Certified with NCQLP National Council on Qualifications for the Lighting Professions

3 Summary Quick Review of LED Lighting How They Work Compontents Key Terms When Evalulating LEDS Do s and Don ts of LED Lighting Common Mistakes Made What To Do Instead Why

4 WHAT IS LED

5 The Digital Revolution LED lighting is transforming the entire landscape* 93% 7% 2008 <25% Traditional lighting 2020 LED lighting >75% *Market estimate based on internal Philips study

6 What is a LED? Light Emitting Diode LEDs are semiconductor diodes Semiconductors are materials with ability to conduct electrical current The diodes are formed by combining two different semiconductor materials to form a PN junction (P=charged positive(holes) and N charged negative(electrons) By applying current, electrons(n) are forced to move to one direction and P to the opposite direction Photons (light) are generated when the positive and negative charges recombine. 6

7 How LEDs Work The diodes are formed by combining two different semiconductor materials to form a PN junction (P=charged positive(holes) and N charged negative(electrons) By applying current, electrons(n) are forced to move to one direction and P to the opposite direction Photons (light) are generated when the positive and negative charges recombine. 7

8 How LEDs Produce Millions of Colors 8

9 How LEDs Produce White Light There are two methods of producing white light with LEDs: The RGB white method produces white light by combining the output from red, green, and blue LEDs. The phosphor white method produces white light in a single LED by combining a shortwavelength LED, such as blue or UV, and a yellow phosphor coating Encapsulant White Light Phosphor Coating Absorbed Light Heat 9 Blue chip

10 How Do LEDs Make White Light? Phosphor coating converted LED Source Encapsulant Absorbed Light White Light Phosphor Coating Heat Blue chip 10

11 Summary LED Source LED Source is a Solid State Light source - semiconductor component A semiconductor device that converts electrical energy directly into discrete color of light Made from different materials and substrates Made in chip fabrication factories No brass, glass and gas ( solid state ) White LED Sources are a blue LED device + phosphor LED Chip Light emitted forward 11 Reflector Cathode lead PC board Anode lead Cathode lead Gold wire Heatsink or slug Light emitted forward Plastic lens Sillicone encapsulent InGaN Semiconductor Flip Chip Solder connection Reflector cup 5 mm LED high power LED

12 PARTS OF A LED

13 LED Source Array Multiple LED sources are typically mounted to a printed circuit board (PCB) in an array LED source PCBs are typically fiberglass (FR4) or metal core (typically aluminum) Metal core PCBs conduct heat better due to lower thermal resistance and therefore are commonly used for high-power or high-output applications FR4 PCB MC PCB 13

14 COB Chip On Board Multiple LED chips are packed together as a single lighting module LED Array COB

15 LED Lighting Optics Primary optics are frequently part of the LED source Secondary optics are utilized to redirect light to produce a specific pattern, distribution or beam of light Secondary optics can consist of lenses, reflectors, light shaping films or a combination of these elements Some light is lost each time it is reflected or refracted, these are the optical losses 15

16 LED Lighting Heat Sink A heat sink is typically required to dissipate the heat produced by the LED sources The interface between the circuit board and the heat sink is critical due to the heat sensitive nature of LED sources A thermally conductive material is typically used between the PCB and heat sink to minimize air gaps which reduce the transfer of heat For retrofit lamps, the size of the heat sink is limited to the envelope of the lamp being replaced, output will be limited by the size of the lamp 16

17 Power Supply and Driver LEDs are typically driven by a constant-current DC power source High brightness or power LED generally refers to an emitter package of roughly 1.2W at a drive current of 350 ma The light output of an LED is proportional to the current applied, most high brightness LED sources will operate across a range of current Drivers also contain temperature sensitive electronic components There is energy lost in the power conversion, power supply efficiencies can vary from 90% all the way down to 50% or lower 17 17

18 Drivers Typically Range ballasts that autosense voltage rather than different voltage taps like HID Drivers comes in different currents, typically 350mA, 530mA, 700mA and 1000mA. The same LED package can produce more light (lumens) by increasing the driver current. This also raises the energy (watts) used Below is performance data from a Lithonia DSX1 LED

19 KEY TERMS

20 LED LIFE Traditional Sources Incandescent Fluorescent & HID Rated Average Life is the length of the operation in hours at which point 50% of a large sample of lamps will still be operational and 50% will not LED LEDs do not fail like traditional sources, the light output just slowly diminishes over time. New methods of rating lamp life were developed L70 Point in hours at which lumen output is depreciated to 70% of initial lumen output L70 is the standard but sometimes different percentages are sometimes used. L80 would be 80% of initial lumen output 20

21 LED Life Testing Initially all manufactures reported LED performance data using their own systems. Because of the variance in testing there was no real way to compare LED components, lamps and luminaires. The Illuminating Engineers Society or IES set up standards in order to evaluate and compare LED components, lamps and luminaires. LM80 is a method for measuring the lumen depreciation of LED lighting sources. It does not measure performance, it only describes how the LED light package will perform over time. Tests are ran hours TM21 Is a way of projecting LED life beyond 6000 hours using LM80 data

22 LM80 Test Report

23 Evaluating Light Output LM IES LM Electrical and Photometric measurements of Solid-State Lighting Products, published by IESNA IESNA - Illuminating Engineering Society of North America Defines how to measure photometry and chromaticity Fixture must be measured at 25C ambient, after thermal stabilization, no seasoning (1000 hour burnin ) Does not have any requirement for product quality IES LM is NOT an international standard BUT it does define the best way to measure LED luminaire photometrics to represent the performance that a customer can realistically expect from the fixture they purchase LED luminaire suppliers should always provide an IES, photometric data file, for their LED luminaire IES file should be produced by a 3rd party, accredited photometric measurement laboratory 23 23

24 Efficacy Vs. Efficiency Luminous efficacy the total luminous flux emitted by the light source divided by the lamp wattage; expressed in lumens per watt (lm/w) Lighting Fixture Efficiency is the ratio of the total lumens exiting the fixture to the total lumens produced by the light source.

25 How Is The LED System Efficacy Determined Lm/W relation from LED component to luminaire system LED LED array Optics Driver Luminaire Color temperature Temperature (Tj) Drive current lm/w Thermal losses (higher Tj) Optical losses Driver losses % % -10%-50% 85 lm/w 70 lm/w 50 lm/w = system efficacy 25

26 Fuzzy Math or Something Else? A wallpack that uses a 400w MH lamp with initial lumens of can be effectively replaced by a LED wallpack that has 7000 lumens, how is this possible? Understanding the below terms will help explain this: Lighting Fixture Efficiency Delivered Lumens Absolute Photometry Relative Photometry

27 Lighting Fixture Efficiency is the ratio of the total lumens exiting the fixture to the total lumens produced by the light source. Luminaire performance in all sources prior to LED was done using Relative Photometry. This process allowed fixtures and lamps to be evaluated separately. Designers could use the best fixture lamp combination for there application. Different lamps could be used in a fixture by simply scaling to the lamp mfgs. lumens even if that was not what the fixture was tested with An example would be a photometric report from a 6 lamp T8 highbay. The report for this fixture could be used with standard 2900 lumen T8 lamps or with High Lumen 3100 T8 lamps With LED fixtures performance is evaluated as a system and results are not relative or scaled to a source that was not tested. This is known as Absolute Photometry, since the result is actual or absolute. Fixture Efficiency is the ratio of the total lumens exiting the fixture to the total lumens produced by the light source. Since LEDs are measured with Absolute Photometry and the entire fixture is looked at as a system, the whole fixture is the source rather than a lamp, therefore by default all LED fixtures are 100% efficient

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30 Delivered lumens Amount of a light source s raw lumen output reaches a surface or area you want to illuminate. We are used to evaluating fixtures based on initial lamp lumens With LEDs delivered lumens are used. Because of absolute photometry LEDs are 100 efficient so all of the stated lumens are used. For other sources luminaire efficiency is dependent on the design of the fixture. Fixtures can lose 50% or more of their initial lamp lumens. Because LED is directional, very little if any light goes where it is unneeded, other sources have unwanted spill or glare. Therefore the math isn t wrong it is just a different way of comparing fixtures.

31 Do s and Don ts with LED Lighting WHAT TO DO AND WHAT NOT TO DO WHEN CONSIDERING A LED LIGHTING SYSTEM

32 ALL LEDS ARE NOT CREATED EQUAL DO NOT assume that just because fixtures have similar stated lumen output that they will perform the same. DO your research, ask for photometric, lighting calcs, or samples fixtures Lumen output may be similar but how and where the light is directed may differ greatly. Although Lumen output is the same, fixture efficacy may vary greatly LED fixtures are built for different environments, if not used as designed then output will be affected

33 KNOW WHO YOU ARE BUYING FROM BEWARE of start up or unheard of lighting manufactures DO use manufactures who are established in the lighting and understand how to make lighting fixtures Since LEDs are basically computer chips, everyone in that industry thinks they can make LED fixtures, but just they can make it doesn t mean they understand what it takes to make a good light fixture What makes LEDs so great is their long life, you want to buy from a company that you know will be around as long as it s projected life or at the very least it s warranty.

34 NEW AND OLD TECHNOLOGY DON T DO NOT assume that any fixture can be converted to LED. DO look for fixtures designed around LEDs or performance tested with LEDs. ALWAYS MIX Lesser manufactures are just buying LED boards and putting them in the housings of traditional source fixtures. Although this sometimes works, more often than not these fixtures will lack the heat sinks or optics need to make the LED perform correctly.

35 TO RETROFIT OR NOT TO RETROFIT DO NOT think that everything can be retrofitted to LED. DO look for retrofit kits designed by the original fixture manufacturer, or kits tested on multiple manufactures LEDs need to stay cool to perform. Putting LEDs kits in fixtures with little space or enclosed space may hinder this. Check for UL listing of kits and watch out for components not being used as intended. Use common sense, there are good retrofits and bad ones and it is usually easy to tell the difference.

36 CHECK YOUR EFFICACY DO NOT use lumen output alone when evaluating LED lighting fixtures. DO look at fixture efficacy (Lumens per Watt) to determine how energy efficient a fixture is Efficacy is like miles per gallon. Higher efficacy fixtures are more energy efficient. When comparing fixtures with equal lighting output the more energy efficient will be the one with the highest efficacy.

37 CHECK YOUR TEMPERATURE DO NOT assume that all fixtures will perform the same regardless of the ambient temperature DO read the fine print and know the max ambient temp of a the fixture and how it will perform as it approaches the upper limits of it While cold is rarely an issue for LED fixtures, heat can affect performance. Fixtures have a max ambient temperature listing and using in environments above the listed temperature can affect performance or cause premature failure Some have offer full performance to a given ambient temperature while others have thermal fold back as they approach the upper limits of their temperature listing. Thermal fold back is a safeguard to where the fixture ramps down as it approaches higher temperatures. While this protects the fixture, output is diminished.

38 EQUIVALENCIES ARE NOT ALWAYS EQUAL DO NOT go by stated equivalencies on cutsheets alone. DO your research and check the lumen output and photometric or have a calculation done comparing with the equivalent traditional light source LED 8089M 80W Shoe Box / Wall Pack / Roadway / Area LED Retrofit LED 8089M40 / M40C (Canada) LED 8089M50 / M50C (Canada) 80W LED Retrofit replaces up to 250W HID installations. Compact design intended for Shoe Box, Wall Pack, and Canopy HID retrofits. E39 Base, Cree high power LED's with type V optics standard, Available 5000K or 4000K CCT. What a manufacturer says is an equivalent to a specific wattage is often different from manufacturer to manufacturer

39 Environmental Concerns DO NOT assume that all LEDs work in all environments DO pay attention to IP Ratings, Class/Div Ratings and other specific fixture listings. Fixtures are designed for specific environments, some for clean spaces while others are designed to protect against harsh environments. Water, dust, chemicals, and hazardous areas may dictate what fixtures should be used.

40 DO NOT assume that just because fixtures look good on paper that they will work for your project DO mock ups on larger jobs or ask for samples if available GLARE Glare is a very hard thing to predict. Often glare issues are only discovered after installation

41 EVER CHANGING DO NOT expect that the fixture you purchased in the past will still be available today DO purchase extras if consistency is important LED fixtures are continually improving and becoming more efficient. The technology is improving at a very rapid pace. Manufactures are constantly introducing new generations and discontinuing older generations

42 CALCULATIONS AND MEASUREMENTS ARE NEVER CONSISTANT DO NOT assume that lighting calculations or measurements will all be done the same way DO have a trusted single source do all your calculations and measurements so that all parameters stay the same. There are many parameters that need to be inputted to do a lighting calculation. Most of which are noted on the output of a lighting calculation. Small changes can make fixture look better then it truly is. Measurements are dependent on meters, and how the measurements are taken, many times these can be manipulated one way or another

43 CHECK YOUR VERTICALS Beware footcandles on the horizontal plane do not tell the whole story. DO realize that in many applications vertical footcandles are just as important Horizontal footcandles are a good measure of lighting on the work plane but do not tell how well a vertical surface will be lit. This is especially important with storage racks, signs, and when lighting walls Vertical calculations can be done but are sometime difficult, samples are also effective

44 SAME COLORS ARE NOT ALL THE SAME DO NOT assume that all fixtures with a specified color temperature will look the same DO look at sample fixtures when comparing to existing fixtures if color is important There are allowable ranges for a given color temperature. A specific color temp may vary slightly from manufacturer to manufacturer Reputable manufactures get first choice of LED chips and have a tighten binning process

45 LONG LIFE LEDS AREN T EVERTHING DO NOT think that a long life LED fixture will never need to be touched again. DO pay attention to warranty information when choosing you LED fixtures LED fixtures are not immune to failures. Although boards are listed and tested to long life hours many times it is the driver that will fail prematurely Good manufactures have 5 or even 10 year warranties, some are limited while others are full performance.

46 LEDS ARE ONLY PART OF THE ENERGY DO NOT stop upgrading your lighting system after switching to LEDs DO take full advantage of LEDs by pairing with an appropriate control strategy EFFICIENT STORY Instant on and off, dimming and driver addressability make LEDs very suited for controls OCC sensors, photocells, dimmers, and networked systems allow for even greater energy savings and ROIs

47 DO NOT think that just because sensors are not needed now they will never be needed DO look into dimming, OCC and controls. Adding or having these options in the future will increase the value of your system FUTURE PROOF Many times adding no/minimal cost options will allow upgrading to multiple control system in the future

48 REPLACEABLE PARTS BEWARE of low cost fixtures that are not designed to be serviced DO look for fixture with replaceable parts LED are long life and energy efficient but they are not immune to problems, make sure that drivers or boards can be changed in event of a failure

49 DON T FORGET THE MAINTENANCE SAVINGS DO NOT use just the energy savings alone to calculate your savings DO include the additional maintenance savings of not having to change lamps and ballasts because of the long life of the LED fixtures Maintenance savings are huge, especially if you have high hours of operation

50 Questions Regarding Your Specific Project? Roundtable with Supporting Vendors