electric light sources

Illumination and acoustics
Electric Lighting Sources
BY-
Dr. Abdultawab Qahtan
Illumination & Acoustics

Revision
• Illuminance ‫االضاءة‬ is a measure of
the amount of light that falls on
a surface per unit area.
• The unit of illuminance is the
lux or foot-candle,
where 1 fc = 10.76 lx.

The relationships among the five
photometric units
Now …you know the difference
between “luminance” and “Illuminance”
Luminous flux is commonly
called light output and is
measured in lumens (lm).
Illuminance is called light
level and is measured in
foot-candles (lux or fc).
Luminance is referred to
as brightness and is
measured in candelas/m2
(cd/m2).
Luminous intensity is a
characteristic of the source
only; it is independent of the
visual sense.
Unites ?
Candela (cd): I
Lumen (lm): Luminous flux ɸ
-Revision

SUSTAINABLE LIGHTING DESIGN
The best and most sustainable
lighting design results when the
three-tier design approach is
applied, and this lecture covers
tier three (electric lighting).
‫يأتي‬ ‫لإلضاءة‬ ‫مستدام‬ ‫تصميم‬ ‫افضل‬ ‫على‬ ‫الحصول‬‫من‬
‫المستوي‬ ‫وفق‬ ‫اإلضاءة‬ ‫تصميم‬ ‫في‬ ‫التدرج‬ ‫تطبيق‬‫الثالث‬ ‫ات‬
‫الموضح‬‫ه‬‫الشكل‬ ‫في‬.
-‫المصدر‬ Refer to chapter 14 (heating, cooling,
lighting, Norbert Lechner)
Fig. Sustainable lighting design

1-LIGHT SOURCES EFFICACY CRI & Life.
 Light sources efficacy
 Highest efficacy & efficiency ?
 Light sources CRI
2-ELECTRIC LIGHT SOURCES:
 Incandescent and halogen lamps
 Discharge lamps
 Fluorescent lamps
 High intensity discharge lamps (mercury,
 Metal halide, and high pressure sodium)
 Solid state lighting
 Comparison of the major lighting sources
3-LIGHTING AND THERMAL CONSIDERATIONS
Lecture
Contents
Lecture2
Sustainable Lighting Design -Tier3:
ELECTRIC LIGHTIN

In choosing a lamp, the three major characteristics are
efficacy (lumens per watt), color rendering (CRI), and the
life of the lamp. To make comparisons easier, all three
characteristics are shown side by side.
‫اختيار‬ ‫يتم‬«‫اللمبة‬»‫بناءا‬‫الخصائص‬ ‫الثالث‬ ‫هذه‬ ‫على‬:‫بالساع‬ ‫والعمر‬ ‫واللون‬ ‫الفعالية‬‫ة‬.
1-LIGHT SOURCES Efficacy, CRI & Life.
‫والعمر‬ ‫واللون‬ ‫الفعالية‬-‫الضوئي‬ ‫للمصدر‬

1-The efficacy of each lamp type is a function of several factors :
a. High-wattage lamps have greater efficacy than low-wattage lamps. For example, a 100-watt
lamp gives off much more light than the combined effect of two 50-watt lamps.
b. The spectral distribution also influences the efficacy of lamps.
For example, warm white lamps have a lower efficacy than cool white lamps.
LIGHT SOURCES Efficacy.
‫الضوئي‬ ‫للمصدر‬ ‫الفعالية‬
‫تعريف‬ Efficacy :
The ratio of lumens per
watt.
100w bulb or two
50w... Which is
brighter?
Source.‫المصدر‬
[Norbert_Lechner]_Heati
ng,_Cooling,_Lighting_Su
st(BookZZ.org) p455

Wattage vs. Lumens
One of the biggest arguments is a light Wattage versus the Lumens and
determining brightness. The old way of looking at how bright a light will
be is to look at the wattage, and with incandescent lamps, the higher the
wattage the lamp is, the brighter it is.
Now we need to focus on the Lumens of the lamp to determine the
brightness of the lamp, especially when it comes to LEDs.
A lumen is the amount of light a certain lamp gives off. If replacing a
standard 150 Watt light bulb which gives off around 2600 Lumens, using
a 42 Watt CFL or a 25 Watt LED is about the equivalent. This lowers the
needed power of the light by over a quarter of the required power to
produce the same light.
--LIGHT SOURCES Efficacy.
‫الضوئي‬ ‫للمصدر‬ ‫الفعالية‬

Efficiency :
Thus, electric lighting, and especially incandescent lighting:
‫قليلة‬ ‫كفاءتها‬ ‫تكون‬ ‫اضاءة‬ ‫الى‬ ‫واالقل‬ ‫حرارة‬ ‫الى‬ ‫الكهرباء‬ ‫من‬ ‫عظيمة‬ ‫كمية‬ ‫تحول‬ ‫التي‬ ‫اللمبات‬:
- uses large amounts of electrical energy
- contributes greatly to the air-conditioning load of a building.
One way that building codes regulate lighting efficiency is by specifying the maximum
number of watts permitted per square foot (watts per square meter) of floor area.
The efficiency requirements of various codes for offices: Refer to page 457- Figure
14.2c & table 14.2
The theoretical maximum
efficacy is where 100
percent of the electrical
energy is converted into
light.
‫نظريا‬:‫القصوى‬ ‫الفعالية‬(‫للمبة‬)‫هي‬
‫تحول‬ ‫عندما‬100%‫الى‬ ‫الكهرباء‬ ‫من‬
‫ضوء‬.
Efficacy & Efficiency ?
The modern incandescent lamp turns only about
7 percent of the electricity into light; the other 93
percent is immediately turned into heat .
The fluorescent lamp is a great improvement, it
still converts only about 28 percent of the
electricity into light.
Watts are not the way to
compare... that just states
how much energy is
consumed and bulbs have a
wide variety of efficiency

Efficacy

LIGHT SOURCES CRI.
‫الضوئي‬ ‫للمصدر‬ ‫اللون‬
Color Rendering Index (CRI): the ability of a light
source to accurately render all frequencies of its color
spectrum when compared to a perfect reference light
of a similar type (color temperature).
Define CRI?

SPECTRAL
DISTRIBUTION OF
LIGHT
SOURCES
Why are danger signals
red when the eye is most
sensitive to yellow and
green?

SPECTRAL
DISTRIBUTION OF
LIGHT
SOURCES

Efficacy and color of Lamp. ‫فعالية‬ ‫بين‬ ‫العالقة‬(‫اللمبة‬)‫واللون‬
The human eye is not equally sensitive to all colors.
yellow-green light is about 680 lumens/ watt,
white light it is only about 200 lumens/watt.
This difference exists because the human eye is not equally sensitive to all
colors. Since the eye is most sensitive to yellow-green light, a lamp of that
color will have the highest efficacy.
The eye is not very sensitive to such colors as red and blue, and any light
containing these colors, such as white, will have a lower efficacy than yellow-
green monochromatic (or one-color) light.
Therefore, whenever color rendition is important, we must accept
the lower efficacy of white light.

The efficacy of each lamp type is shown in the figure bellow as a range because efficacy is a function of
several factors:
Figure, In choosing a lamp, the
three major characteristics are
efficacy (lumens per watt),
color rendering (CRI), and the
life of the lamp. To make
comparisons easier, all three
characteristics are shown side
by side.
‫اختيار‬ ‫يتم‬«‫اللمبة‬»‫بناءا‬‫الثالث‬ ‫هذه‬ ‫على‬
‫الخصائص‬:‫بالساعة‬ ‫والعمر‬ ‫واللون‬ ‫الفعالية‬.
lumens per watt
The incandescent lamp is inefficient when compared
to what else is available.
--LIGHT SOURCES Efficacy, CRI & Life.
‫والعمر‬ ‫واللون‬ ‫الفعالية‬-‫الضوئي‬ ‫للمصدر‬

Color temperature
Reddish light has a technically
lower color temperature, its
frequently described as warm.
Bluish light, which has a higher
color temperature, is described
as cool.
Warmer & cooler describe
color, not temperature

2- ELECTRIC LIGHT
SOURCES:
1- Incandescent And Halogen Lamps
2- Discharge Lamps

I- INCANDESCENT AND
HALOGEN LAMPS
‫التوهج‬ ‫مصابيح‬
THE INCANDESCENT FILAMENT LAMP ‫الفتيل‬ incandescent lamp
Although incandescent
lamps are obsolete for
general illumination,
they are still used for a
number of special
applications.
Fig. 14.1
Common
incandescent
lamp bulb.

How it works?
In an incandescent lamp, light is emitted by electrically heating a
tungsten filament until it is reddish-white-hot (Fig. 14.3a textbook).
By increasing the current, the filament gets hotter and the light
gets whiter (higher color temperature- see the figure bellow).
Unfortunately, a hotter filament also burns out faster. The life of a
typical incandescent lamp is only about 1000 hours.
INCANDESCENT AND
HALOGEN LAMPS- ‫التوهج‬ ‫مصابيح‬
Incandescent lamps wear out as the tungsten filament evaporates
and eventually, as the filament gets thinner, it breaks.
This evaporation of the filament can be reduced by adding halogen
elements to the inert gases inside the lamp to operated at higher
temperatures without shortening lamp life excessively (Fig. 14.3b textbook).
HALOGEN
‫مشكلة‬
‫مصابيح‬
‫التوهج‬
‫المشكلة‬ ‫لحل‬ ‫تطوير‬

--HALOGEN
Because of their intense light and small size, they are very popular as:
 automobile headlamps,
 projector lamps, and
 spotlights for accent lighting.
Halogen lamps have a slightly better efficacy than incandescent lamps,
and a new version called the Halogen IR (infrared) is even better.
CONT--INCANDESCENT AND
HALOGEN LAMPS
However, LEDs are
significantly better and
will likely displace many
halogen lamps in the
near future.

 The advantages of incandescent
lamps:
 low cost;
 immediate start and restart;
 simple, inexpensive dimming;
 simple, compact installation requiring
no accessories;
 cheap fixtures;
 focusability as a point source;
 high power factor; (related to voltage)
 lamp life independent of the number
of starts; and
 skin‐flattering, full‐spectrum color.
From a human factor perspective, the
full‐spectrum quality of incandescent
light, with higher amounts of light in
the red wavelengths, is best for
rendering skin tones.
 The disadvantages:
- low efficacy- means more fixtures and
larger heat gain than with more
energy‐efficient alternative sources.
- short lamp life- results in high
lamp‐replacement labor costs,
- critical voltage sensitivity- Voltage
sensitivity may require careful and
expensive circuit design.
Cont--INCANDESCENT LAMPS ‫التوهج‬ ‫مصابيح‬

 Applications:
Incandescent lamp use should be limited to the following
applications:
1. Where use is infrequent.
2. Where there is frequent short‐duration use.
3. Where low‐cost dimming is required.
4. Where the point source characteristic of the lamp is important, as in
focusing fixtures.
5. Where minimum initial cost is essential.
6. Where its characteristically good color rendering is desired.
INCANDESCENT LAMPS ‫التوهج‬ ‫مصابيح‬

APPLICATION examples :
Halogen lamps can be appropriate for accent
lighting of small areas or objects, such as retail
displays, sculpture, and paintings.
Halogen lamps are especially appropriate when
sparkle and specular reflectance are desired in
the display of glassware, silverware, or jewelry.
However, LED lamps are increasingly replacing halogen
lamps.
Recommendation:
Incandescent lamps should be used as little as possible and halogen
lamps should be used economically.
CONT--INCANDESCENT AND
HALOGEN LAMPS

II- DISCHARGE LAMPS
All of these lamps are based on a phenomenon known as discharge,
in which an ionized gas rather than a glowing hot solid tungsten
filament emits the light. All discharge lamps require an extra device
known as a ballast
The long life and high efficacy of the
discharge lamps are more than enough to
offset the extra cost of the ballast and the
higher cost of each lamp when compared
to incandescent lamps.
All discharge lamps require a ballast
first to start the lamp and then to
maintain the proper operating current.

a- FLUORESCENT LAMPS
Although the fluorescent lamp
was first introduced in the
1930s, it is still one of the best
light sources. It is available in a
wide variety of sizes, colors,
wattages, and shapes.

FLUORESCENT LAMPS-
Compact fluorescent lamps (CFLs)
Compact fluorescent lamps (CFLs) are widely used around the world
as replacements for incandescent lamps because of their high efficacy,
warm color, and small size.
The spiral shape is a result of the goal to get the most light out of the
smallest-size fluorescent lamp.

FLUORESCENT LAMPS
Five characteristics define the operation of a fluorescent lamp:
1- Efficacy: Light output per unit of power input- (lumens per watt).
2- Lumen maintenance: The decreasing output of light as a lamp ages. The lumen
output of a fluorescent tube decreases rapidly during the first 100 hours of
burning, and thereafter much more slowly.
3- Lamp life: Average (statistically defined) lamp life expectancy.
4- Temperature and humidity: How a lamp responds to environmental operating
conditions. Outside of the optimal operating temperature range (5–25°C), there is
a rapid drop in light output and difficulty in starting. High humidity causes
electrical leakage along the lamp surface, lowering the starting voltage provided
by the ballast.
5- Dimming: Controlling light production of the lamp.

b- Neon Lamps
Neon lamps are close relatives of fluorescent
lamps. These lamps use such gases as neon,
which gives off red light, and argon, which
gives off blue light. Through the use of different
combinations of gases, colored glass, and
phosphors, a large variety of rich, colored light
sources is possible.
The main advantage of these lamps is that
they can be custom-made to almost any
desired shape.

c- Cold-Cathode Lamps
Cold-cathode: like fluorescent lighting,
cold-cathode lighting produce mainly white
light, but it has a much lower efficacy than
fluorescent lighting. Like neon, it is
custom-made for a particular project, and
like neon, it is for decorative rather than
functional purposes.

d- HIGH INTENSITY DISCHARGE
LAMPS
- Mercury‐vapor lamps
- Metal Halide, and
- High Pressure Sodium)
High intensity discharge lamps have important
characteristics in common:
 (HID) lamps are very efficient light sources that in
size and shape are more like with a point source.
 They all require a few minutes to reach maximum
light output, and
 They will not restrike immediately when there is a
temporary voltage interruption.
Some discharge Lamps include
additional substances, like
mercury, sodium, and metal halides,
which are vaporized during startup
to become part of the gas mixture.

Application
Mercury‐vapor lamps are applicable to indoor and outdoor use, with
proper attention to performance characteristics.
 The most common exterior application is for parking lots.
 Indoor application is generally limited to mounting heights of 3 m
AFF (above finish floor) or higher, to avoid direct glare potential
and permit adequate floor area coverage.
 Their use in industrial spaces and stores was once common, but
today use of metal–halide lamps is typical.
 Warehouses and non‐color‐sensitive industrial areas continue to
use mercury‐vapor lamps.
e- Mercury‐vapor lamps
The mercury‐vapor lamp was the first HID lamp to
be developed

f- METAL–HALIDE LAMPS
This lamp began its life in the early 1960s as a modified mercury‐vapor lamp. Major
advances in miniaturization, color rendering, color temperature, and consistency—
by the addition of halides such as thallium, indium, and sodium to the arc
tube—resulted in changes in the output, efficacy, color, and life of the lamp. Metal–
halide lamps have excellent color characteristics and therefore almost unlimited
applicability.
Various configurations of
metal–halide lamps

The common shapes of high intensity discharge (HID) lamps.

III. SOLID STATE
LIGHTING
The most fully developed lamp is the light
emitting diode (LED), while the organic light
emitting diode (OLED) is only now
coming on the market.
LEDs are ideal for creative, decorative,
and task lighting.
As their efficacy increases, they are also
being used for general area lighting.

COMPARISON OF
THE
MAJOR
LIGHTING
SOURCES
Refer to the textbook
page 466
‫الصفحة‬ ‫في‬ ‫مدونة‬ ‫المقارنة‬466

Understanding the characteristics of light sources
will allow a designer to use them appropriately for
energy efficiency and to provide visual and
thermal comfort.
Choosing light sources for buildings—
whether daylight or electric
light need to concern on lighting and thermal
considerations
3- lighting and thermal
considerations
‫الحرارية‬ ‫واالعتبارات‬ ‫اإلضاءة‬
Lighting in American nonresidential buildings
consumes 25% to 60% of
the electric energy utilized
‫عب‬ ‫توصلت‬ ‫الدولية‬ ‫الطاقة‬ ‫وكالة‬‫ر‬
‫تستهلك‬ ‫اإلنارة‬ ‫أن‬ ‫إلى‬ ‫دراساتها‬
2650‫على‬ ‫الساعة‬ ‫في‬ ‫وات‬ ‫تيرا‬
‫نحو‬ ‫لتشكل‬ ‫العالمي‬ ‫المستوى‬19%
‫عنها‬ ‫وينتج‬ ‫الكهرباء‬ ‫استهالك‬ ‫من‬
‫ق‬ ‫الكربون‬ ‫أكسيد‬ ‫لثاني‬ ‫انبعاثات‬‫درها‬
1889‫ما‬ ‫وهو‬ ‫سنويا‬ ‫طن‬ ‫ميغا‬
‫يساوي‬70%‫من‬ ‫العالم‬ ‫انبعاثات‬ ‫من‬
‫الركاب‬ ‫سيارات‬.
‫من‬ ‫التدريجي‬ ‫التخلص‬ ‫أن‬ ‫ورأى‬
‫الفعالة‬ ‫غير‬ ‫المتوهجة‬ ‫المصابيح‬
‫أعلى‬ ‫بمصابيح‬ ‫عنها‬ ‫واالستعاضة‬
‫فعالي‬ ‫األكثر‬ ‫اآلليات‬ ‫إحدى‬ ‫كفاءة‬‫ة‬
‫وزياد‬ ‫الطاقة‬ ‫في‬ ‫وفورات‬ ‫لتحقيق‬‫ة‬
‫الدخل‬ ‫ذات‬ ‫لألسر‬ ‫المتاح‬ ‫الدخل‬
‫كبي‬ ‫انبعاثات‬ ‫وخفض‬ ‫المنخفض‬‫رة‬
‫التقلي‬ ‫دون‬ ‫المناخ‬ ‫تغير‬ ‫ومكافحة‬‫من‬ ‫ل‬
‫ما‬ ‫وهو‬ ‫اإلضاءة‬ ‫جودة‬‫إضافة‬ ‫يتطلب‬
‫نفقات‬‫صغيرة‬‫نسبيا‬.
---‫باإلمكان‬‫استهالك‬ ‫تخفيض‬
‫من‬ ‫السعودية‬ ‫في‬ ‫السنوي‬ ‫الكهرباء‬
‫وسائل‬ ‫تحسين‬ ‫خالل‬‫اإلضاءة‬.
http://www.alriyadh.com/7
87995

incandescent lamp
Halogen lamp: incandescent
lamp that has a small amount of
a halogen. fluorine (F), chlorine
(Cl), bromine (Br), iodine (I), and
astatine (At).
mercury vapor lamp
CFL lamp
Compact fluorescent lamp
fluorescent lamp-
Metal-halide lamp should
not be confused
with Halogen lamp
Make a
Discussion

HPS Lamp
High Pressure Sodium
LED lamp
Light-emitting Diode
induction lamp
Plasma lamp
ESL lamp
Electron-stimulated luminescence
Make a
Discussion

Luminaires

Assyment1:
Describe the characteristics of electric light sources
available in the KSA market, including the limits,
capabilities and applications of each source?
‫وعيوب‬ ‫ومميزاتها‬ ‫السعودية‬ ‫السوق‬ ‫في‬ ‫المتوفرة‬ ‫المصابيح‬ ‫أنواع‬ ‫اهم‬ ‫بين‬‫ها‬
‫المباني،؟‬ ‫في‬ ‫وتطبيقاتها‬
‫لوحة‬ ‫عمل‬A1‫المحد‬ ‫التصنيف‬ ‫بحسب‬ ‫اللمبات‬ ‫أنواع‬ ‫جميع‬ ‫منتجات‬ ‫لعرض‬‫في‬ ‫د‬
‫والمحاضرة‬ ‫المصدر‬-
Thank you

electric light sources

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