This chapter describes the different lighting efficiency measures in lieu with the application of architecture, design and planning.

1. Lighting
Introduction
Types of lighting systems
Assessment of lighting systems
Energy efficiency opportunities
1

2. Introduction
Background
• Lighting energy consumption
• 20-45% in commercial buildings
• 3-10% in industrial plants
• Significant energy savings can be
realized with a minimal capital
investment
2

3. Introduction
Basic Theory
• Light: electromagnetic waves in
space
• Light is emitted through:
a) Incandescence
b) Electric discharge
c) Electro luminescence
d) Photoluminescence
3

4. Introduction
Definitions and Common Terms
 Lumen
• 1 lumen = the photometric equivalent of the watt
• 1 lumen = luminous flux per m2 of a sphere
with 1 m radius and a 1 candela isotropic light
source at the centre
• 1 watt = 683 lumens at 555 nm wavelength
 Lux
• metric unit of measure for illuminance on a
surface: 1 lux = 1 lumen / m2 4

5. Introduction
Definitions and Common Terms
 Luminous intensity (I)
• measured in Candela (cd)
 Luminous flux (lm)
• 4 x luminous intensity
5

6. Introduction
Definitions and Common Terms
 Installed load efficacy
• Average maintained illuminance on a working
plane: lux/W/m2
 Installed load efficiency ratio
• Target load efficacy / Installed load
 Rated luminous efficacy
• Rated lumen output of the lamp / rated power
consumption
• Lumens per watt 6

7. Introduction
Definitions and Common Terms
 Room index
• Ratio for the plan dimensions of the room
 Target load efficiency
• Installed load efficacy considered achievable
under best efficiency
• Lux/W/m²
 Utilization factor
• A measure of the effectiveness of the lighting
scheme 7

8. Introduction
Definitions and Common Terms
 The inverse square law
• Defines the relationship between illuminance from
a point source and distance
E = Iluminance
E=I/ d2 I = Luminous intensity
E1 d12 = E2 d22 d = distance
8

9. Introduction
Definitions and Common Terms
 Color temperature
• Color appearance of a lamp and the light it
produces
• Measured in Kelvin (K)
• Incandescent lamps: “true value” color
temperature
• Fluorescent and high intensity discharge
(HID) lamps: correlated color temperature
9

10. Introduction
Definitions and Common Terms
 Color rendering index (CRI)
Color CIE general color Typical application
rendering rendering Index(Ra)
groups
1A Ra > 90 Wherever accurate color rendering is
required e.g. color printing inspection
1B 80 < Ra < 90 Wherever accurate color judgments are
necessary or good color rendering is
required for reasons of appearance e.g.
display lighting
2 60 < Ra < 80 Wherever moderate color rendering is
required
3 40 < Ra < 60 Wherever color rendering is of little
significance but marked distortion of color
is unacceptable
4 20 < Ra < 40 Wherever color rendering is of no
importance at all and marked distortion of
colour is acceptable
Table 1. Applications of color rendering groups (Bureau of
10
Energy Efficiency, 2005)

11. Training Agenda: Electricity
Introduction
Types of lighting systems
Assessment of lighting systems
Energy efficiency opportunities
11

12. Types of Lighting Systems
• Incandescent lamps
• Tungsten Halogen Lamps
• Fluorescent lamps
• High pressure sodium lamps
• Low pressure sodium lamps
HID lamps
• Mercury vapour
• Metal halide
• Blended
• LED lamps 12

13. Types of Lighting Systems
Incandescent Lamps
• Emit radiation mainly in
the visible region
• Bulb contains vacuum or
gas filling
• Efficacy: 12 lumen / Watt
• Color rendering index: 1A
• Color temperature: 2500 –
2700 K
• Lamp life <2000 hrs (BEE India, 2005)
13

14. Types of Lighting Systems
Tungsten-Halogen Lamps
• Tungsten filament and a halogen gas
filled bulb
• Tungsten atoms evaporate from the hot
filament and move to cooler wall of bulb
• Advantages:
• Efficacy: 18 lumens/Watt • More compact
• Longer life
• Color rendering index: 1A • More and whiter light
• Color temperature: warm • Disadvantages:
• Cost more
• Lamp life < 4000 hrs • Increased IR and UV
• Handling problems
Tungsten halogen lamps
14
(BEE India, 2005)

15. Types of Lighting Systems
Fluorescent Lamps
• 3 – 5 times as efficient as standard incandescent
lamps and last 10 – 20 times longer
• Electricity passes through a gas or metallic vapor
and causes radiation
• Fluorescent tubes are hot cathode lamps
15
© UNEP 2006

16. Types of Lighting Systems
Fluorescent Lamps Features:
Halo-phosphate
• Efficacy – 80 lumens/Watt (HF
gear increases this by 10%)
• Different types (T12, • Color Rendering Index –2-3
T10, T8 and T5) • Color Temperature – Any
differing in diameter • Lamp Life – 7-15,000 hours
Tri-phosphor
and efficiency • Efficacy – 90 lumens/Watt
• Color Rendering Index –1A-1B
• Most efficient at • Color Temperature – Any
ambient temperature • Lamp Life – 7-15,000 hours
of 20-30 oC,
• Compact fluorescent
lamps (CFL) have
much smaller
luminaries
Compact fluorescent lamp (CFL)
16
(BEE India, 2005)

17. Types of Lighting Systems
High Pressure Sodium (HPS) Lamps
• Used in outdoor and industrial applications
• Consist of: ballast, high- voltage electronic starter,
ceramic arc tube, xenon gas filling, sodium, mercury
• No starting electrodes
• High efficacy: 60 – 80 lumen/Watt
• Color rendering index: 1 - 2
• Color temperature: warm
• Lamp life < 24,000 hrs
17
BEE India, 2005

18. Types of Lighting Systems
Low Pressure Sodium (LPS) Lamps
• Commonly included in the HID family
• Highest efficacy: 100 - 200 lumen/Watt
• Poorest quality light: colors appear black, white
or grey shades
• Limited to outdoor applications
• Efficacy: Color rendering index: 3
• Color temperature: yellow
• Lamp life < 16,000 hours
18

19. Types of Lighting Systems
Mercury Vapor Lamps
• Oldest HID lamp
• Consists of: arc tube with mercury and argon
gas and quartz envelope, third electrode, outer
phosphor coated bulb, outer glass envelope
• Long life and low initial costs
• Very poor efficacy: 30 – 65 lumens/Watt
• Color rendering index: 3
• Color temperature: intermediate
• Lamp life: 16000 – 24000 hours
19

20. Types of Lighting Systems
Metal Halide Lamps
• Works similar to tungsten halogen lamps
• Largest choice of color, size and rating
• Better efficacy than other HID lamps: 80 lumen/Watt
• Require high voltage ignition pulse but some have
third electrode for starting
• Color rendering index: 1A – 2 BEE India, 2005
• Color temperature:
3000 – 6000 K
• Lamp life:
6000 – 20,000 hours 20
© UNEP 2006

21. Types of Lighting Systems
Blended Lamps
• “Two-in-one”: 2 light sources in 1 gas filled bulb
• Quartz mercury discharge tube
• Tungsten filament
• Suitable for flame proof areas
• Fit into incandescent lamps fixtures
• Efficacy: 20 – 30 lumen/Watt
• Lamp life < 8000 hours
• High power factor: 0.95 BEE India, 2005
• Typical rating: 160 W 21

22. Types of Lighting Systems
LED Lamps
• Newest type of energy efficient lamp
• Two types:
• red-blue-green array
• phosphor-coated blue lamp
• Emit visible light in a very narrow spectrum and
can produce “white light”
• Used in exit signs, traffic signals, and the
technology is rapidly progressing
• Significant energy savings: 82 – 93%
• Longest lamp life: 40,000 – 100,000 hours
22

23. Types of Lighting Systems
Reflectors
• Impact how much light reaches
area and distribution pattern
• Diffuse reflectors:
• 70-80% reflectance but declining in time BEE India,
2005
• painted or powder coated white finish
• Specular reflectors:
• 85-96% reflectance and less decline in time
• Polished or mirror-like
• Not suitable for industrial open-type strip
fixtures 23

24. Types of Lighting Systems
Gear
• Ballast
• Current limiting device
• Helps voltage build-up in fluorescent lights
• Ignitors
• Start metal halide and sodium vapor lamps
24

25. Types of Lighting Systems
Comparing lamps
Lum /
Color
Watt Life
Type of Lamp Rendering Typical Application
Rang Av (Hours)
Index
e g.
Incandescent 8-18 14 Excellent Homes, restaurants, general 1000
lighting, emergency lighting
Fluorescent Lamps 46-60 50 Good w.r.t. Offices, shops, hospitals, 5000
coating homes
Compact fluorescent lamps 40-70 60 Very good Hotels, shops, homes, 8000-10000
(CFL) offices
High pressure mercury 44-57 50 Fair General lighting in factories, 5000
(HPMV) garages, car parking, flood
lighting
Halogen lamps 18-24 20 Excellent Display, flood lighting, 2000-4000
stadium exhibition grounds,
construction areas
High pressure sodium 67- 90 Fair General lighting in factories, 6000-12000
(HPSV) SON 121 ware houses, street lighting
Low pressure sodium (LPSV) 101- 150 Poor Roadways, tunnels, canals, 6000-12000
SOX 175 street lighting
25

26. Training Agenda: Electricity
Introduction
Types of lighting systems
Assessment of lighting systems
Energy efficiency opportunities
26

27. Assessment of Lighting Systems
Designing with Light
• Better lighting: increased productivity
• Two main questions for designer:
• Choose correct lighting level
• Choose quality of light (color rendering)
27

28. Assessment of Lighting Systems
Designing with Light
Recommended light levels for different tasks (BEE India, 2005)
Illuminance Examples of Area of Activity
level (lux)
General Lighting for rooms 20 Minimum service illuminance in exterior circulating areas,
and areas used either outdoor stores , stockyards
infrequently
and/or casual or simple 50 Exterior walkways & platforms.
visual tasks 70 Boiler house.
100 Transformer yards, furnace rooms etc.
150 Circulation areas in industry, stores and stock rooms.
200 Minimum service illuminance on the task
300 Medium bench & machine work, general process in chemical and
food industries, casual reading and filing activities.
General lighting for 450 Hangers, inspection, drawing offices, fine bench and machine
interiors assembly, colour work, critical drawing tasks.
1500 Very fine bench and machine work, instrument & small precision
mechanism assembly; electronic components, gauging &
inspection of small intricate parts (may be partly provided by
local task lighting)
Additional localized lighting 3000 Minutely detailed and precise work, e.g. Very small
for visually exacting tasks parts of instruments, watch making, engraving. 28

29. Assessment of Lighting Systems
Recommended Illuminance Levels
 Scale of illuminance
• Illuminance for all non-working interiors > 20
Lux
• Factor 1.5 is the smallest significant difference
in effect of illuminance
• Therefore the following scale is recommended:
20–30–50–75–100–150–200–300–500–750–1000
–1500–2000, …Lux 29

30. Assessment of Lighting Systems
Recommended Illuminance Levels
 Illuminance ranges recommended for
interior or activity
• Middle value (R) for working interiors
• Higher value (H) for visual work
• Lower value (L) where accuracy is non-
important
30

31. Assessment of Lighting Systems
Methodology for Efficiency Study
• Step 1: Make inventory of lighting system
elements and transformers
Table: Device rating, population and use profile
S. Plant Lighting Rating in
Population Use / Shifts as I /
N Locati Device & Watts Lamp
Numbers II / III shifts / Day
o. on Ballast Type & Ballast
Table: Lighting transformer/rating and population profile
S. Plant Lighting Measurement Provisions
Numbers
N Locatio Transformer Rating Available Volts / Amps /
Installed
o. n (kVA) kW/ Energy
31

32. Assessment of Lighting Systems
Methodology for Efficiency Study
• Step 2: Measure and document the Lux levels
• Step 3: Measure and document the voltage and
power consumption at input points
• Step 4: Compare the measured Lux values with
standard values as reference
• Step 5: Analyze the failure rates of lamps,
ballasts and the actual life expectancy levels
32

33. Assessment of Lighting Systems
Methodology for Efficiency Study
Step-6 : identify improvement options, for example:
• Maximum sunlight use options through
transparent roof sheets
• Replacements of lamps and ballasts to more
energy efficient types
• Selecting interior colors for light reflection
• Modifying layout as per needs
• Providing individual / group controls for
lighting
33

34. Training Agenda: Electricity
Introduction
Types of lighting systems
Assessment of lighting systems
Energy efficiency opportunities
34

35. Energy Efficiency Opportunities
Use Natural Day Lighting
• North lighting
• Glass strips across the roof
• Sky lights with fiber reinforced plastic
(FRP)
• Atrium with FRP dome
• Natural light from
windows
35

36. Energy Efficiency Opportunities
De-lamping to Reduce Excess
Lighting
• Effective method to reduce energy
consumption
• Reducing lamp height combined with
de-lamping: illuminance hardly affected
• Complicated for series wired ballasts
• Less problematic with parallel wired
ballast
36

37. Energy Efficiency Opportunities
Task Lighting
• Low wattage lamps at task
• General illuminance at lower level
• Benefits:
• Reduce number of lighting fixtures
• Reduce lamp wattage
• Save considerable energy
• Better illuminance
• Aesthetically pleasing ambience 37

38. Energy Efficiency Opportunities
High Efficiency Lamps & Luminaries
Examples (9 – 75% savings):
• Metal halide lamps to replace mercury /
sodium vapor lamps
• HPSV lamps where color rendering is
not critical
• LED panel indicator lamps to replace
filament lamps
• Luminaries with mirror optics instead of
conventional painted ones 38

39. Energy Efficiency Opportunities
Reduction of
Percentage
Lighting Feeder 1
2
Voltage 3
Supply voltage percentage
5
4
6
• Can save
4 6
energy 3
5
• Provided drop
2
1
in light output 1) Lamp current 2) Circuit power, 3) Lamp power,
is acceptable 4) Lamp output 5) lamp voltage 6) lamp efficiency
Effect of voltage variation of
fluorescent tube light parameters
(BEE India, 2005) 39

40. Energy Efficiency Opportunities
Electronic Ballasts instead of
Electromagnetic Ballasts
• Oscillators that convert supply frequency to
about 20,000 – 30,000 Hz
• Available for fluorescent tube lights, LPSV and
HPSV lamps
• Benefits in fluorescent tube lights:
• Reduced power loss: 1 Watt instead of 10-15
Watt
• Improved efficacy at higher frequencies
• Elimination of starter: no flickering
40

41. Energy Efficiency Opportunities
Low Loss Electromagnetic Ballasts
for Tube Lights
Loss per tube lights:
• Standard ballasts: 10 – 15 Watts
• Low loss ballasts: 8 - 10 Watts
41

42. Energy Efficiency Opportunities
Timers, Twilight Switches &
Occupancy Sensors
• Timers: switching of unnecessary lights
• Twilight switches: depending on availability of
daylight
• Occupancy sensors: depending on presence of
people
• Applicable for general areas, conference
rooms, cubicles, restrooms, exteriors
42

43. Energy Efficiency Opportunities
T5 Fluorescent Tube Light
• Slimmer tubes than T12 and T8 tubes
• Improved luminaire efficiencies by 7%, and with
super-reflective aluminum luminaire by 11-30%
• Mercury reduction: 3 mg instead of 15 mg per
lamp
• Can only be operated with electronic ballasts
and not existing luminaries
43

44. Energy Efficiency Opportunities
Lighting Maintenance
• Light levels decrease >50% due to aging
lamps and dirt on fixtures, lamps and
room surfaces
• Maintenance options:
• Clean equipment
• Replace lenses
• Keep spaces bright and clean
• Re-lamping
44