Lighting architecture notes lecture

1. LED (LIGHT EMITTING DIODES) LIGHTS
•LED lights are widely used as replacement of bulbs in general lighting.
• Extremely energy efficient and extremely long-lasting light bulbs. An
LED light bulb can reduce energy consumption by 80-90% and last
around 100,000 hours.
•They even light up faster than regular bulbs. They are more expensive
presently.
•Widely used in hotels, hospitals, restaurants, jewellery showrooms,
exhibitions, art galleries, cosmetic counters, museums, factories,
gymnasiums, yards, advertising boards, streets, buildings, lawns and
gardens, house holds and places where spot lighting is needed and
other general lighting.
•LED lights save energy and is green which is why it is important to
convert to LED - also helps us to control the global warming up to some
extent.

2. Type of Lights
•Spot lights, Light Bulbs, Street Lights, Landscape Lighting.
• LED for Indoor and Outdoor Signage, flashlights, security products,
traffic safety products.
•LED Strips with all range of colors, including red, blue, green, white,
warm white, purple, pink and RGB. Waterproof and non-waterproof LED
strips are both available.

3. •What does LED stand for?
LED stands for Light Emitting Diode
•Is an LED a bulb?
LEDs do appear to be bulbs, but in fact are not. LEDs are tiny
semiconductors encapsulated in plastic which protects their
components and helps to focus the light.
•What is the difference between an incandescent bulb and LED?
Incandescent creates light by the use of a filament. When power is
applied, the filament glows and generates heat - which in turn produces
light. LEDs are just the opposite. LEDs create light through a 'cold
process'. When power is applied to semiconductors (usually gallium,
arsenic and phosphorous), they're stimulated by the movement of
electrons, which creates photons. Photons are the light that is visibly
seen by humans.

4. WHAT IS LED?
•Led is a diode that emits light. A diode is a device that allows current to
flow in one direction.
•Almost any two conductive materials will form a diode when placed in
contact with each other.
•When electricity is passed through the diode the atoms in one material
are excited to a higher energy level. The atoms in that first material have
too much energy and need to release that energy. The energy is then
released as the atoms shed electrons to the other material. During this
energy release light is created.
•A semiconductor has electrical conductivity intermediate to that of a
conductor and an insulator. Semiconductors differ from metals in their
characteristic property of decreasing electrical resistivity with
increasing temperature.

5. •Do LEDs have a wire filament?
No, LEDs operate using entirely different components. LEDs are diodes -
they only allow power to move in one direction. The anode (+) is where
the current comes in and the cathode (-) is where the current goes out,
much like the positive and negative terminals of a battery. Incandescent
bulbs project light in every direction (omni directional) as opposed to
LED lights which project light in specified directions (such as 20, 50 and
120 degrees) due to their package design and layout.
•Why do LEDs use such little power?
A. LEDs donot use a filament where a conductor is heated and light is
created. Filament based lighting consumes more power than the light
produced. LEDs produce very little amounts of heat and do not use
filaments making them far more efficient in consumption and output.

6. •Are LEDs affected by extreme conditions?
LEDs are geared for harsh environments. LEDs function from -40F to
180F. There is no delay or required "warm up time" for LEDs to function.
•How long do LEDs last?
LEDs are rated by manufacturers to operate under normal conditions for
approximately 10 years or 100,000 hours of continuous use. As LEDs get
older, they tend to dim and fade but aren't susceptible to blinking like
incandescent or fluorescents.
Since a single LED is a relatively low power device (by comparison with
other light sources), constructing LED arrays is attractive.

7. LED VS Other Light Source / LED
Light Sources Light
Output
Graph
Efficiency
Power
Consumption
(W)
Same Light
Output
Actual
Lighting
Fixture
Efficiency (%)
Luminance
(lm/m2)
Efficiency
(lm/w)
Lifetime (hour)
(6 hr/day)
Incandescent 107 50% 730 12.16 1,000
(167 days)
Halogen 80 50% 900 15 3,000
(500 days)
Energy Saving
Fluorescent
Lamp
27 68% 1,100 55 8,000
(1,333 days)
High Power LED 16 95% - 100% 62 62 30,000
(5,000 days)

8. Brightness VS Height
Ceiling
Lighting
Fixture
3W LED X 6 PCS 3W LED X 12 PCS 3W LED X 18 PCS
Normal Picture
Hanging Light
1.6 m
From Ceiling
160 -- 175 Lux 500 – 575 Lux N/A
Desk Height 2 m
From Ceiling
108 – 138 Lux 370 – 470 Lux 450 – 600 Lux
Floor 3 m
From Ceiling
41- 62 Lux 125 – 185 Lux 130 – 200 Lux

9. WHAT ARE THE ADVANTAGES OF LED?
•Energy consumption 1/10 of incandescent.
•High levels of brightness and intensity.
•Low voltage and current requirement.
•Low radiated heat - Low operating temperature - (vs. halogen which
can be over 600F).
•High reliability (resistant to shock and vibrations).
•Instant cold start.
•Reduced maintenance.
•Contains no mercury (fluorescent has 10 - 40mg Hg per bulb).
•Compatible with dimmer switches – can be easily controlled and
programmed.
•Long source life.
•Contain no toxic elements, and last so long that disposal is not much of
an issue.