Transcript Electrical Power Utilization

Electrical Power Utilization LEDs
Guide:
Dr. S.S. Bhatt
Pranav Deshpande
Dhiraj Deshmukh
Vamsi Sriram
Ashlesha Dupare
Preethi Eashwar
BT14EE021 to BT14EE025
Topics
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What are LEDs?
Working Principle of LEDs
Applications
Advantages and disadvantages
LEDs vs. Conventional Lighting Sources
Government Schemes on LEDs
Domestic Lighting
Street Lighting
LED Lens and Beam Angle
LED Drivers
LED Downlights
Comparison Of Various LED Brands
What Is An LED?
 LED - Light Emitting Diode
 LED is a two lead semi conductor light source which emits
monochromatic light when operated in forward bias.
 The LED is actually a PN Junction diode.
 Available in many colours as well as infra-red radiation.
 The wavelength of the light emitted depends upon the
material used.
What is an LED?
Working Principle
 The P‐N junction emits light when electrical energy is
applied to it.
 This phenomenon is called electroluminescence, defined as
the emission of light from a semi‐conductor under the
influence of an electric field.
 The charge carriers recombine in a forward‐biased P‐N
junction as the electrons cross from the N‐region and
recombine with the holes existing in the P‐region. Some
energy must be dissipated here. It is released in the form
of photons.
Working Principle
 In Gallium arsenide phosphide (GaAsP) and Gallium
phosphide (GaP) semiconductors, the electrons
dissipate energy by emitting photons.
 The LED should always be operated in forward bias. If
operated in reverse bias, the LED may get damaged.
 Longer lead - Anode
 Shorter lead - Cathode
Working Principle
HISTORY OF LED
 For over 30 years, LEDs have been used in various areas of
application, whether for industrial systems, car lights or
advertising. In the course of recent years, the white LEDs'
luminous efficacy has increased to a startling 130 lumens per
watt and more.
A short glance back over the history of the LED:
 1907 - The Englishman Henry Joseph Round discovers that
inorganic materials can light up when an electric current is
applied. In the same year, he publishes his discovery in the
journal "Electrical World".
 1921 - The Russian physicist Oleg Lossew again observes the
"Round effect" of light emission. In the succeeding years, from
1927 to 1942, he examined and described
this phenomenon in greater detail.
 1935 - The French physicist Georges Destriau discovers light emission in
zinc sulfide. Today Georges Destriau is credited as the inventor of
electroluminescence.
 1951 - The development of a transistor marks a scientific step forward in
semiconductor physics. It is now possible to explain light emission.
 1962 - The first red luminescence diode (type GaAs), developed by
American Nick Holonyak, enters the market. This first LED in the visible
wavelength area marks the birth of the industrially-produced LED.
 1993 - Japanese Shuji Nakamura develops the first brilliant blue LED and
a very efficient LED in the green spectrum range (InGa diode). Some
time later he also designs a white LED..
 1995 - The first LED with white light from luminescence conversion is
presented and is launched on the market two years later.
 2006 - The first light-emitting diodes with 100 lumens per watt are
produced. This efficiency can be outmatched only by gas discharge
lamps.
 2010 - LEDs of a certain color with a gigantic luminous efficacy of 250
lumens per watt are already being developed under laboratory
conditions.
 Today, further development towards OLED is seen as the technology of
the future.
Efficiency and operational
parameters
Color
Wavelength
range(nm)
Typical
Efficacy
(Lumen/watt)
Typical
efficiency
coefficient
620 < λ < 645
Red
Red-orange 610 < λ < 620
72
98
0.39
0.29
520 < λ < 550
490 < λ < 520
460 < λ < 490
93
75
37
0.15
0.26
0.35
Green
Cyan
Blue
Applications Of LED
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Mobile phone technologies
Signs and Hoardings
Automative Application
Signal application
Illumination
Indicators
Sensors
Applications in Mobile Technologies
 Flash feature the in camera of mobile phones.
Generally white LEDs are used for mobile phones .
 Used in LCD(liquid crystal display): LCD is a display
technology for televisions and tablets and mobile
phones as well.
 Nowadays LED screens are available as well.
Signs and Hoardings:
 Full Color Video Screen.
 Traffic Lights : For stop ,look
and go actions.
Automative Applications:
 Interior Lighting - Instrument
Panels & Switches.
 Exterior Lighting - CHMSL, Rear
Stop/Turn/Tail
 Truck/Bus Lighting - Retrofits,
New Turn/Tail/Marker Lights
Sensors
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Daylight sensor
Bar Code Readers
Line follower sensors
Optical Switches
ADVANTAGES OF LED
 Efficiency: LEDs emit more lumens per watt than incandescent
light bulbs. The efficiency of LED lighting fixtures is not affected
by shape and size, unlike fluorescent light bulbs or tubes.
 Color: LEDs can emit light of an intended color without using any
color filters as traditional lighting methods need. This is more
efficient and can lower initial costs.
 Size: LEDs can be very small (smaller than 2 mm) and are easily
attached to printed circuit boards.
 Warm Up time: LEDs light up very quickly. A typical red indicator
LED will achieve full brightness in under a microsecond. LEDs
used in communications devices can have even faster response
times.
 Cycling: LEDs are ideal for uses subject to frequent on-off cycling, unlike
incandescent and fluorescent lamps that fail faster when cycled often,
or high-intensity discharge lamps (HID lamps) that require a long time
before restarting.
 Dimming: LEDs can very easily be dimmed either by pulse-width
modulation or lowering the forward current. This pulse-width
modulation is why LED lights, particularly headlights on cars, when
viewed on camera or by some people, appear to be flashing or
flickering. This is a type of stroboscopic effect.
 Cool light: In contrast to most light sources, LEDs radiate very little heat
in the form of IR that can cause damage to sensitive objects or fabrics.
Wasted energy is dispersed as heat through the base of the LED.
 Slow failure: LEDs mostly fail by dimming over time, rather than the
abrupt failure of incandescent bulbs.
 Lifetime
 Shock resistance
 Focus
DISADVANTAGES
 High initial price
 Temperature dependence: LED performance largely depends on the
ambient temperature of the operating environment or "thermal
management" properties. Toshiba has produced LEDs with an operating
temperature range of -40 to 100°C, which suits the LEDs for both indoor and
outdoor use in applications such as lamps, ceiling lighting, street lights, and
floodlights.
 Voltage sensitivity: LEDs must be supplied with a voltage above their
threshold voltage and a current below their rating. Current and lifetime
change greatly with a small change in applied voltage. They thus require a
current-regulated supply (usually just a series resistor for indicator LEDs).
 Blue hazard: There is a concern that blue LEDs and cool-white LEDs are now
capable of exceeding safe limits of the so-called blue-light hazard as defined
in eye safety specifications.
 Blue Pollution
LED Tubelight vs. Fluorescent
Tubelight
Costs
Rs.16002000
Payback
3-4 years
Life
10-15 years
Efficiency
About 110-120
lumens per watt
T-5 Fluorescent
Tubelight
Rs. 500
6 months to
1 year
3-4 years
110 lumens per
watt
Regular
Fluorescent T-8
Tubelight
Rs. 100
3-4 years
60-80 lumens
per watt (lower
for one with
electromagnetic
ballast)
T-8 LED
Tubelight
LEDs vs. conventional lighting
technologies
Light Output
Light Emitting
Diodes (LEDs)
Incandescent
Light Bulbs
Compact
Fluorescents
(CFLs)
Lumens
Watts
Watts
Watts
450
4-5
40
9-13
800
6-8
60
13-15
1,100
9-13
75
18-25
1,600
16-20
100
23-30
2,600
25-28
150
30-55
LEDs vs. conventional lighting
technologies
Environmental
Impact
Contains TOXIC Mercury
RoHS Compliant
Light Emitting Diodes
(LEDs)
Incandescent
Light Bulbs
Compact Fluorescents
(CFLs)
No
Yes - Mercury is very toxic
to the health and the
environment
Yes
Yes
No - contains 1mg-5mg of
Mercury and is a major
risk to the environment
204 kg/year
2041 kg/year
477 kg/year
No
Carbon Dioxide Emissions
(30 bulbs per year)
Lower energy consumption
decreases: CO2 emissions, sulfur
oxide, and high-level nuclear
waste.
LEDs vs. conventional lighting
technologies
Energy Efficiency
& Energy Costs
Light Emitting Diodes
(LEDs)
Incandescent
Light Bulbs
Compact
Fluorescents
(CFLs)
Life Span (average)
50,000 hours
1,200 hours
8,000 hours
6 - 8 watts
60 watts
13-15 watts
329 KWh/yr
3285 KWh/yr
767 KWh/yr
Watts of electricity used
(equivalent to 60 watt bulb).
LEDs use less power (watts) per unit
of light generated (lumens). LEDs
help reduce greenhouse gas
emissions from power plants and
lower electric bills
Kilo-watts of Electricity used
(30 Incandescent Bulbs per year
equivalent)
Government Schemes
 A National programme for LED-based Home and Street
Lighting has been launched by the government of India Domestic Efficient Lighting Programme (DELP).
 Under the scheme, LED bulbs are sold at heavily subsidized
rates.
 The main aim is to save electricity by replacing lighting
sources incandescent bulbs.
 As of 19th March 2016, a total of 8 crore LED Bulbs have
been distributed under the scheme. This led to a savings of
28.58 GWh of energy per day.
Domestic and Commercial Lighting
 Omnidirectional LED Bulbs – These use a diffusing
lens to scatter light in all directions.
 Dimmable LED Bulbs
 LED Tubelights – Intended as a replacement for
conventional tubelights. Some have a power
consumption of 8 Watt or 16 Watt unlike conventional
tubelights.
 Flood Lights
LED STREET LAMPS
An LED street light (also referred to as LED road
lighting) is an integrated light-emitting
diode (LED) light fixture that is used for street
lighting.
 The current trend is to use high power 1 watt
LEDs
 Heat sinks are used. They facilitate the flow of
hot air away from the LEDs.
 The lifespan of an LED street light is determined
by its light output compared to its original
design specification. Once its brightness
decreases by 30 percent, an LED street light is
considered to be at the end of its life.
Advantages of LED street lights:
 Low energy consumption
 Long and predictable lifetime: The projected lifetime of LED
street lights is usually 10 to 15 years. LEDs themselves do not
generally fail or "burn out" in a way comparable to other
technologies, lifetimes are typically set by a decrease in luminous
output of 30%. But the functional lifetime of an LED typically
projected to last about 50,000 hrs.
 More accurate color rendering: The color rendering index(CRI)is
the ability of a light source to correctly reproduce the colors of
the objects in comparison to an ideal light source. Improved color
rendering makes it easier for drivers to recognize potential road
hazards.
 Quick turn on and off: LEDs once switched on come on with full
brightness instantly.
 No problem with immediate restart: Unlike mercury vapor, metal
halide and sodium vapor lamps (commonly used in street
lighting), LEDs do not have a problem restarting immediately.
 Higher light output even at low temperatures.
Disadvantages of LED street lights:
 There is a main risk from glare. A luminance level higher
than 10,000 cd/m2 causes visual discomfort.
 LEDs have concentrated point sources which cause
luminance of 1000 times greater than comfort visual level.
 The initial cost of LED street lighting is high. The material
used in LEDs are often made on sapphire or other expensive
substrates.
 LED street lights make light pollution ,they emit more blue
and green light(which is sensitive for human eyes)
 It also increases impacts on bird migration and animal
behaviour!
Beam Angle
 Refers to the angle between the two planes of light where
the intensity is at least 50% of the maximum intensity at
center beam. The average beam angle on most par lights is
25 degree, which works well for most purposes.
 Example – Consider a 40° light bulb. At 20° on either side of
that central point the light intensity is ½ the intensity right
under the bulb(20° + 20° = 40°).
 Also, the lamp with greater beam angle looks dimmer. 25° &
40° lamps both have the same light output, but the 40°
covers much more space and, therefore, looks a little dim.
LED Lens
 The beam angle is determined by the type of lens used in
the LED fixture.
 The smaller lens on the
right is typical in RGB
fixtures (one color lamp
under each lens) and this
sample is a 25 degree
lens. Beam angles ranging
from 10 degree (narrow)
to 60 degree (wide) are
common.
LED Lens
 The lens on the right is a larger lens
This type is common on Quad-LED
fixtures in which all 4 LED color
lamps are located under each lens,
hence the reason for the larger size.
 Larger lenses have wider beam
angles of 25 - 60 degrees.
 Notice the textured surface, the
purpose of this is to produce better
color mixing.
 However, the textured surface will
reduce beam intensity by a small
percentage.
Different Types Of Beam Spread In
LED Lens
25° Beam spread
Different Types Of Beam Spread In
LED Lens
45° Beam spread
LIGHT SPREAD OF DIFFERENT LED
BEAM ANGLES FOR VARIOUS
CEILING HEIGHTS
NAMES OF LED BULB BEAM ANGLES
LED Drivers
 An LED driver is an electrical device which regulates the
power to an LED or a string of LEDs.
 It provides a constant quantity of power to the LED as its
electrical properties change with temperature.
 The power level of the LED is maintained constant by the
LED driver as the electrical properties change throughout
the temperature increases and decreases seen by the LED
or LEDs.
 Without the proper driver, the LED may become too hot
and unstable, therefore causing poor performance or
failure.
LED DRIVER CIRCUIT
Applications Of LED Drivers
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Industrial / outdoor lighting
Commercial lighting
Residential lighting
Cell phone camera flash
Automotive interior or tail lights
Garden lighting
Portable flashlight / torch
Signage
Elevator lighting
LCD backlighting
LED DOWN LIGHT
LED down lights are advanced low energy luminaires that outperform
halogen and CFL. Energy efficient and providing substantial energy
savings. These units are extremely small in size so they can be discreetly
hidden within the decor.
Advantages Of LED Downlight
1. LED down light bulbs can last up to 50,000 hours, which is
10 times longer than your average halogen or CFL down
light.
2. Another benefit you get from LED down lights is that they
are safe and do not produce a lot of heat, which means
they can even be installed near flammable.
3. Although they cost more, their energy savings of up to 90
percent mean that they will easily pay for themselves
within 1 or 2 years after installation, depending on usage.
1.
2.
3.
4.
5.
6.
PHILIPS
HAVELLS
OSRAM
EVEREADY
WIPRO
OREVA
7.
8.
9.
10.
BAJAJ
SYSKA
SURYA
NTL LEMNIS
Top Branded LED bulb comparison:
NOW QUESTION IS WHICH BRAND IS
THE BEST ?
Technical parameters to consider while buying a high quality light are
Lumens output (Lumens/watt), Power Factor, CRI (Color rendering index)
and LED life in hours.
Parameter
Average
Good
Best
Lumens/watt
75
90
100
Power factor
0.7
0.8
0.9
CRI
60
70
80
15000
20000
25000
Led life in hrs
THANK YOU!