Overview of recent technology for energy efficient in lighting in textiles

Overview of Recent Technology
Trends in Energy-Efficient Lighting
N. Narendran, Ph.D.
Lighting Research Centre
Rensselaer Polytechnic Institute
Troy, NY 12180 – USA
April 27-28, 2009
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Acknowledgments
 USAID/SARI/PA Consulting
 SLSEA
 LRC faculty, staff, and students
 LRC program and project sponsors
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Electric lighting history
 In 1879, Thomas Alva
Edison demonstrated
the first successful light
bulb.
 Over the past 125 years,
incandescent and gas discharge
technologies have provided many
shapes and sizes of light sources

for a variety of lighting
applications.
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Light source technologies
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Wavelength(nm)
Relative Energy
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Wavelength(nm)
Relative Energy
Incandescent
Fluorescent

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Wavelength(nm)
Relative energy
High Pressure
Sodium
Spectral power
distribution (SPD)
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Wavelength(nm)
Relative Energy
Luminous flux and efficacy

 Lumen and lumens per watt are two key
metrics commonly used in the lighting
industry to quantify performance of light
sources.
 Lumen: The luminous flux accounts for
the sensitivity of the eye by weighting the
radiant power at each wavelength with
the human eye response function.
 Lumens per watt: Luminous efficacy of a
light source is the total luminous flux
emitted by the lamp divided by the total
lamp power (electrical) input.
Flux (Φ) = 683 ∫ S
λ
V
λ
dλ (lm)
Efficacy = Φ / W (lm/W)
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Light source technologies
 Incandescent and halogen light
sources range in efficacy from 2
to 30 lm/W.
 Fluorescent light sources range in
efficacy from 25 to 105 lm/W.

 High-intensity light sources range
in efficacy from 25 to 150 lm/W.
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Incandescent
 Filament heating produces light
¾ Only 5% of the total energy input is
converted to light and the rest is heat
¾ Very inefficient
 Efficacy
¾ Generally around 15 lm/W
 Color
¾ CRI = 95+
¾ CCT = 2500K – 3000K
 Life (average rated)
¾ 750 – 2000 hours
¾ Dimming can extend life
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Halogen
 A halogen lamp contains an inert gas
and a small amount of halogen.
 Efficacy
¾ PAR and MR Lamps (line or low

voltage)
9 10 to 25 lm/W
¾ IR PAR Lamps (Infrared reflector)
9 20 to 30 lm/W

Color
¾ CRI – 95+
¾ CCT – Typically 3000K
 Life (average rated)
¾ 2000 hours
¾ Shortens if consistently dimmed below
80%
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Fluorescent
 A fluorescent lamp is a low-intensity gas-discharge lamp
that uses electricity to excite mercury vapor to produce
ultraviolet (UV) radiation that causes a phosphor to
fluoresce and produce light.
¾ Linear fluorescent lamps (LFL) and compact fluorescent lamps
(CFL) are popular choices for conserving energy.
¾ About 20% to 30% of the total energy input is converted to light.
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Compact fluorescent lamp (CFL)
 Types:
¾ Pin-base for dedicated fixtures
¾ Screw-base self-ballasted
 Efficacy:
¾ 25 to 60 lm/W
 Color
¾ CRI = 82 typical
¾ CCT = 2700K, 3000K, 3500K,
4100K, 5000K
 Life
¾ 6,000 to 10,000 hours
9 Frequent on-off switching can
reduce life significantly
9 Dimming is possible but can
reduce life
Ö
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Linear fluorescent lamp (LFL)
 Lamp Efficacy
¾ Ranges from 65 to 105 lm/W
 Color
¾ CRI = 82 typical
¾ CCT = 2700K to 5000K
 Life

¾ 20,000 to 30,000 hours
9 Frequent on-off switching can
reduce life significantly
9 Dimming can reduce life
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Ballasts for LFL
 Fluorescent lamps require a
ballast to operate
¾ Magnetic
9 Low frequency (60 Hz) operation
9 May produce audible hum
9 May produce noticeable lamp flicker
9 Inefficient lamp operation
¾ Electronic
9 High frequency (20 to 60 kHz)
operation
9 Quiet
9 No noticeable lamp flicker
9 More efficient lamp operation
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High intensity discharge (HID)
 Metal halide lamps produce light by

passing an electric arc through a mixture
of gases, which causes a metallic vapor to
produce radiant energy.
¾ It contains a high-pressure mixture of argon,
mercury, and a variety of metal halides in a
compact arc tube.
¾ About 24% of the total energy input is
converted to light.
 Three types of HID lamps:
¾ Mercury vapor lamp
¾ Metal halide lamps
¾ High-pressure sodium (HPS) lamp
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Ballasts for HID
 Metal halide lamps require ballasts to
regulate the arc current flow and
deliver the proper voltage to the arc.
¾ Probe-start metal halide: Contains a
starting electrode within the lamp to
initiate the arc when the lamp is first lit.
¾ Pulse-start metal halide: No starting
electrode but has a special starting circuit
to generate a high-voltage pulse to the
operating electrodes.
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Lighting controls
 Manual controls
¾ Wall switch: on or off
¾ Dimmers
 Automatic controls
¾ Time clocks
¾ Occupancy sensors
9 Infrared
9 Ultrasonic
9 Dual technology
¾ Panel relays
¾ Centralized controls
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Efficacy and energy savings
 Energy use depends on the connected load and
time of use
¾ Watt-hours
 MYTH: High efficacy light sources always save
more energy than low efficacy light sources.
¾ Spatial – light not reaching the application area is
wasted light (energy)
¾ Temporal – light beyond the required time is wasted light

(energy)
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Energy Conservation
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Different forms of luminous efficacy
 Light source (lamp) efficacy: Total lumens
out of the light source divided by the total
input power to the light source
 Light source + ballast efficacy: Total
lumens out of the light source divided by the
total input power to the ballast
 Luminaire efficacy: Total lumens exiting
the luminaire divided by the total input
power
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Luminaire efficacy
 In this example, the total luminaire efficiency is 33%
to 54%.

 A 60 lm/W CFL would yield:
¾19 to 32 lm/W final system efficacy in these luminaires
¾IR Halogen PAR lamp would be a better choice than
combinations A to J
CFL
24W CFL Fixture
0%
20%
40%
60%
80%
100%
ABCDEFGH I JKL
Flux exiting the fixture
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Application efficacy
Lighting Objective – Illuminating the picture on the wall
 Application lumens: Total lumens reaching a picture area
 Wasted lumens: Lumens beyond the area of the picture
Application
lumens
Wasted
lumens
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0
10
20
30
40
50
60
Halogen F8T5
sample 1
F8T5
sample 2
LED
Sample 3
LED
Sample 4
Efficacy (lm/W)
Application Efficacy (lm/W) (Fixture + Driver) Efficacy (lm/W)
-12%
+32%
0
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40
50
60
Halogen F8T5
sample 1

F8T5
sample 2
LED
Sample 3
LED
Sample 4
Efficacy (lm/W)
Application Efficacy (lm/W) (Fixture + Driver) Efficacy (lm/W)
-12%
+32%
Application efficacy
 In this example, compared to sample 1, sample 3 is
designed better to direct the exiting lumens to the area
where it is needed.
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Application efficacy
 Not switching off the light at the right time wastes energy.
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Environmental considerations
 Mercury
¾ An essential component of many

energy-efficient light bulbs.
¾ Throwing these lamps into the garbage,
which ultimately end up in landfills, can
pollute the environment.
– /> Health Effects
¾ Mercury exposure at high levels can
harm the brain, heart, kidneys, lungs,
and immune system of people of all
ages.
– /> Lamp Disposal
¾ Programs that promote energy-efficient
technologies must also consider proper
disposal programs.
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Selecting Technologies
for Energy-efficient
Lighting Application
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Lamps for residential applications
 Today, linear and compact

fluorescent lamps can be used in
houses to conserve energy and
reduce nighttime power demand.
A variety of CCTs
available for the
different applications