Introduction to LED Lighting
Presented by:
Darrell Huffman
Mercer-Zimmerman
Learning Objectives
LO1:
What is an LED?
LO2:
LED Terminology
LO3:
Why LED?
LO4:
LED Equivalency
LO5:
LED Control
LO1: What is an LED?
Lighting Emitting Diode
An LED is a type of solid-state diode that emits light when voltage is applied.
The light output of an LED is a function of its physical construction material
used, and amount of current passing through the device. LED can also radiate
infrared (heat) energy or UV energy.
Generated Light from Direct Electronic
Transitions in a Semiconductor Device
 No Filament Failures

Ongoing Technological Advancement
 AC/DC Conversion
Thermal Management
Optical Efficiency
LED luminaires use light emitting diodes to produce light very efficiently. The
movement of electrons through a semiconductor material illuminates the tiny
light sources we call LEDs. A small amount of heat is released backwards, into a
heat sink, in a well-designed product; LEDs are basically cool to the touch.
LO1: What is an LED?
White Light:
There are two primary ways of producing white light-emitting diodes (WLEDs), LEDs that generate highintensity white light.
•
One is to use individual LEDs that emit three primary colors— red, green, and blue —and then mix all
the colors to form white light.
•
The other is to use a phosphor material to convert monochromatic light from a blue or UV LED to broadspectrum white light, much in the same way a fluorescent light bulb works.
•
Phosphor: A coating of phosphorescent material which photons from a royal blue LED pass through
causing those photons to exit with a different color property.
•
Remote Phosphor: A phosphor conversion technique in which photons from a royal blue LED pass
through a phosphor material that is not attached to the LED chip.
white light
y
red
green
w
m
phosphor
Blue
c
LED
blue
RGB SYSTEM
PHOSPHOR SYSTEM
LO1: What is an LED?
LED Die (Chip)
• Light emitting semiconductor.
LED Package
• LED Chip integrated with electrical, thermal,
optical, and mechanical interfaces.
LED Array
• An assembly of LED packages on a printed
circuit board that are intended to connect an
LED driver.
LO1: What is an LED?
LED Module
• A component part of an LED light source that includes one or more
LED arrays connected to the LED driver. Electrical, thermal, optical,
and mechanical components may also be part of an LED module.
LED Driver
• A power source with integral LED control circuitry designed to meet
the specific requirements of a LED array.
Heat Sink
• A part of the thermal system that conducts or convects heat away
from sensitive components, such as LEDs and electronics.
LED Luminaire
• A complete LED lighting unit consisting of a light source and driver
together with parts to distribute light, to position and protect the
light source, and to connect the light source to a branch circuit.
LO1: What is an LED?
Component Selection, Luminaire Design, Final Assembly, Testing
Thermal Management
Power
Input
Dimmer
or
Control
System
Power
Supply &
Driver
Power
Management
LED
Package
Heat
Sink
Secondary
Diffuser
Optics
Optical Management
Luminaire Assembly Integrity
Light
Output
LO2: LED Terminology
Lumen Output
•
The total lumens emitted of a light source, system or solution.
Color Rendering Index (CRI)
•
A measure of the degree of color shift objects undergo when illuminated by
the light source as compared with the same objects when illuminated by a
reference source of comparable color temperature. The reference source
has a CRI of 100.
Correlated Color Temperature (CCT)
•
The absolute temperature of a blackbody whose chromacticity most nearly
resembles that of the light source. Usually specified in Kelvin (K). The lower
the Kelvin temperature, the warmer the light feels, or appears.
Efficacy
•
The light output of a light source divided by the total electrical power input to
that source, expressed in lumens per watt (lm/W).
LO2: LED Terminology
LM-79 Test
• LM-79: Measures an LED luminaire or integral lamp as a whole
system
Total Luminous Flux (Lumens)
Luminous Intensity Distribution (Photometrics)
Luminous Efficacy (LPW – Lumens Per Watt)
Color Characteristics (CRI, CCT, etc.)
• LM-79 requires that solid state lighting products be tested to
“Absolute Photometry.” Conventional HID/Fluorescent uses
“Relative Photometry.”
• Absolute Photometry - lumen output of LED based luminaires
that is dependent on the chip, thermal management, drive
current and optical system.
LO2: LED Terminology
LM-80 Lumen Maintenance Information
• LM-80: Measures lumen maintenance of light source to the array or
module but not as a complete system.




3 Temperatures to be tested at: 55C, 85C and 3rd is selected by LED
Manufacturer.
6K hours min testing period. 10K preferred.
Testing on a component level
approved method for measuring lumen depreciation of solid-state
(LED) light sources, arrays & modules
• LM-80 does not cover measurement of luminaires.
• LM-80 does not define or provide methods for estimation of life.
LO2: LED Terminology
TM-21
• TM-21: provides a method for determining an LED luminaire or
integral replacement lamp’s expected operating life, based on initial
performance data collected per LM-80 testing.
• For 6,000 hrs of data (LM-80 min) and up to 10,000 hrs, use data
from the last 5,000 hrs.
• For greater than 10,000 hrs of testing, use the last ½ of the collected
data.
• TM-21 can extrapolate up to 6 times the data.
• IES has determined end-of-life of LED products to be when the
lumen output is 70% of its initial output (30% depreciation). This is
known as L70.
•
Conventional lamp life is rated when 50% of the lamps in an installation
burn out. This is known as B50.
 LED Luminaires and lamps do not “fail” like conventional sources. LED
luminaires and lamps gradually decrease in output over time.
LO2: LED Terminology
50,000 Hours is…….?
137 Years
68.5 Years
34.2 Years
22.8 Years
17.1 Years
11.4 Years
5.7 Years
1 Hour/Day
2 Hours/Day
4 Hours/Day
6 Hours/Day
8 Hours/Day
12 Hours/Day
24 Hours/Day
LO2: LED Terminology
Efficacy
(LPW)
CCT
(°K)
CRI
Lifetime (Hours)
LED
100+
2700 – 6500
70 – 95
30,000–100,000+
Incandescent
8 – 15
2500 – 2800
97+
750 – 1500
Tungsten Halogen
10 – 15
2800 – 3200
97+
3000 -- 5000
Compact Fluorescent
50 – 80
2700 – 5000
80 – 85
10,000 – 16,000
Linear Fluorescent
70 – 110
2700 – 8000
50 – 90
24,000 – 55,000+
Induction
48 – 75
2700 – 5000
80 – 85
100,000
Metal Halide
70 – 125
2700 –
10,000
60 – 95
10,000 – 20,000
High Pressure
Sodium
70 – 145
1800 – 2550
20 – 25
16,000 – 55,000
Lamp Type
LO2: LED Terminology
Lighting Facts
• Lighting Facts® is a program of the U.S. Department
of Energy that showcases LED products for general
illumination from manufacturers who commit to
testing products and reporting performance results
according to industry standards.
Energy Star
• ENERGY STAR is a joint program of the U.S.
Environmental Protection Agency and the U.S.
Department of Energy whose goal is to help
consumers save money and protect the environment
through energy efficient products and practices.
LO3: Why LED? – Financial & Emotional
Reduced
Maintenance
Long Life,
No Lamp
Controls
Integration
Replacement
Financial
Visual
Comfort
(safety)
Energy
Savings
Instant
on/off
(safety)
Reduced
Carbon
Footprint
Mercury /
Lead Free
Emotional
15
LO3: Why LED? – Environmentally Friendly
Most LED Fixtures Comply With RoHS,
(Restriction of Hazardous Substances)
• No mercury or lead
• 4 mg of mercury (most commercial lamps have <5 mg) is
enough to contaminate up to 7,000 gallons of freshwater.
• The mercury from one fluorescent bulb can pollute 6,000
gallons of water beyond safe drinking levels.
• Each year and estimated 600 million fluorescent lamps
are disposed of in U.S. landfills amounting to 30k lbs of
mercury waste.
Sources: EPA.gov, NaturalNews.com, lamprecycle.org, energywiseepa.org/why/mercury
LO3: Why LED? – Rugged Construction
Solid State Construction
• LED chips are completely embedded in
an epoxy resin enclosure which is much
more sturdy than traditional glass bulbs
and fluorescent tubes.
• With no loose or moving parts LEDs are
virtually indestructible.
LO3: Why LED? – Thermal Management
Thermal Management
• Every 10C° ↑ = ½ life of LED
• Every 10C° ↑ = 5% loss in output
• Every 10C° ↓ = 2x life of LED
• Every 10C° ↓ = 5% gain in output
LO3: Why LED? - Controllability
HID:
LED:
100 lm/W
100 lm/W
40% Utilization Efficiency
Lighting Efficacy 40 LPW
80% Utilization Efficiency
Lighting Efficacy 80 LPW
Energy Savings, Higher min., Better uniformity
LO4: LED Equivalency
• Best way to compare Traditional Lamp Sources vs LED is
by doing calculations via lighting calculation software.
• Fixture selection is dependent on the following:
•
–
–
–
–
–
•
–
–
If replacing existing:
What type of fixture are you replacing (troffer, parabolic, etc)?
How many lamps are in the existing fixtures?
Are you needing the same amount of light, more light, less light?
Look at IES recommendations and run calcs.
Are you trying to do a one-for-one replacement?
What LED product are you trying to use?
If new space:
What type of space are you trying to light? Look at IES
recommendations and run calcs.
What LED product are you trying to use?
LO4: LED Equivalency
• In addition, as you have been learning, it is hard to do a direct
comparison of LED lumens to traditional source lumens. With
LED’s, the lumen output given is typically the DELIVERED
lumens. With traditional sources, you are typically looking at the
raw lumens of the lamps and then have to take into account the
efficiency of the fixture.
• However, you can do some quick comparisons to give you an
idea.
– Interior: 3 Lamp T8 Fluorescent Recessed Troffer
• Bare Lamp Lumens = 2950 lumens x 3 = 8850 lumens
• Fixture Efficiency (look at fixture cutsheet) = let’s assume 78%
• 8850 lumens x 0.78 = 6903 lumens (need an LED fixture that has approximately
6903 DELIVERED lumens)
– Exterior: Look at street side Downward Delivered Lumens.
LO4: LED Equivalency
TYPE III 250W MHPS
TYPE III 107W LED
LO4: LED Equivalency
HID
vs.
71% Luminaire Efficiency [15,620 Fixture lms]
55 LPW [Luminaire Efficacy]
283W PSMH
LED
100% Luminaire Efficiency [10,680 fixture lms]
99.8 LPW - Luminaire Efficacy
22,000 lms
107W LED [Absolute]
10,680 lms
62% Energy Reduction
Street Side = 45%
9,908 lms
Street Side = 82.8%
8,845 lms
7,134 lms
0.912 LLF [Light Loss Factor]
8,067 lms
[63.4% of Fixture Lumens]
0.72 LLF [Light Loss Factor]
Comparible Task Lumens While Saving 30-75% Energy.
LO4: LED Equivalency
HID (Metal Halide)
vs.
LED
LLF = BF * LDD * LLD
Ballast Factor
1.0
Ballast Factor
1.0
DIRT (LDD)
0.90
DIRT (LDD)
0.95
Lumen Depr’n (LLD)
0.96
Lumen Depr’n (LLD)
LLD = Mean Lumens
0.65-0.80
[40% Rated Life]
÷ Initial Lumens
LLF = 0.9 * 0.80 = 0.72
LLD =
Lumen depreciation per TM-21
50,000 Hrs @ 25°C Ambient
LLF = 0.95 * 0.96 = 0.912
LO4: LED Lighting Case Study
Aflac Support Center Headquarters – Columbus, GA
Before
After
Project Description:
 (61) Existing 1000W MH fixtures
 Replaced with (53) Cooper Ventus LED (303W)
25
LO4: LED Lighting Case Study
Aflac Support Center Headquarters – Columbus, GA
Before
After
Benefits:
 Reduced load by 76% (49 kW)
 Average $17,500 in annual savings (166,000 kWh)
 3.4 Year Payback
 Maintenance-free for over 10 years
 Reduction equivalent to 120 metric tons of CO2 emissions annually
26
LO5: LED Control
Verify control system, LED Driver & method are compatible
Fixture
LED Driver
Control Unit
Switching control
Bi-Level Switching
Dimming Methods
•
•
•
•
•
• Option 1: Turn off
50% of the LEDs.
• Option 2: Dim LED
module to 50%.
• Forward Phase (Leading
Local wall station
Schedule-based
Occupant-based
Lumen-based
Panel-based
Edge, Triac, SCR, Incandescent)
• Reverse Phase (Electronic
Low Voltage, Trailing Edge)
•
•
•
•
Three-wire (Lutron Hi-Lume)
0 – 10V
DMX 512
DALI
LO5: LED Control
Start by asking a few questions:
• Will loads be switched or dimmed?
• If dimmed, is the LED driver dimmable?
• Which dimming method(s) does the LED driver support?
(i.e. forward phase, 0-10V, etc.)?
• Which dimming controls have been tested for
compatibility with the LED driver?
• Can the LED driver/control provide the desired minimum
dim level?
• Are there special requirements from the driver or
controls manufacturer (ie inrush power)?
• Is color changing control required?
• Does the fixture need to work with existing controls? If
so, what are the existing controls?
QUESTIONS?