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Lighting: Fundamentals and Applications

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Title: Lighting: Fundamentals and Applications


1
LightingFundamentals and Applications
2
Outline
  • Why Look at Lighting ?
  • Amount of Light Needed
  • Lamp Types
  • Lighting Improvements
  • Fixtures Replacements
  • Lighting Controls
  • Lighting Components Ballasts, etc.
  • HVAC Interactions
  • Maintenance
  • Room Cavity Ratio
  • Inverse Square Law

3
Why Look at Lighting
  • In a typical commercial facility, lighting
    accounts for about 1/3 of the total energy costs
  • In some facilities such as retail operations
    lighting may account for over ½ of the energy
    costs
  • Improving existing lighting systems can result in
    energy cost savings of 25 30

4
Principles of Efficient Lighting Design
  • Meet target light levels
  • Efficiently produce light
  • Efficiently deliver light
  • Automatically control lighting operation

5
Factors in Successful Lighting Applications
  • Amount of lighting required
  • Energy Efficiency efficacy
  • Lumen output of lamps and fixtures
  • Color Rendition Index (CRI)
  • Color Temperature
  • Types of light sources
  • Lighting quality

6
Color Temperature Scale
7
Amount of Light Needed for Specific Applications
  • In general, we use far more light than necessary
    for many applications and tasks
  • Light levels are measured in Footcandles, using a
    Footcandle meter (inexpensive)
  • Acceptable minimum standards of light levels are
    set by the Illuminating Engineering Society (IES)

8
Some Typical Light Levels Needed
9
Lamp Types
  • Incandescent
  • Halogen Incandescent
  • Fluorescent
  • Compact Fluorescent
  • Mercury Vapor
  • Metal Halide
  • Compact Metal Halide
  • High Pressure Sodium
  • Low Pressure Sodium
  • New Technologies

10
Fixture Types
  • Suspended Luminaires
  • Direct - Indirect - Combination
  • Surface Mounted Luminaires
  • Wrap-around diffuser
  • Wrap-around refractor
  • Recessed Fluorescent Troffers

11
Recessed Troffers
  • Diffusers and louvers
  • Lenses (refractive)
  • Asymmetric (Bat-Wing) Lenses
  • Specular Parabolic Louvers
  • Deep Parabolic Louvers

12
Lighting System Design Lumen Method
  • Assumption All are will have the same
    foot-candles

Example To provide 55 ft-candles in the working
surface of a roof shingle facility, of 40ft
60ft production area, compute the number of lamps
required. Consider two 3,000 lumen lamps in a
fixture, and assume a light loss factor of 70
with a coefficient of utilization of 75
13
How to Select the Right LightingComponents and
Systems
  • Most of the potential cost savings from new
    retrofit lighting comes from 3 areas
  • Replacing incandescent lamps with more efficient
    fluorescent or compact FL lamps
  • Upgrading fluorescent fixtures with improved
    components
  • Installing lighting controls to minimize energy
    costs

14
Upgrading Existing Fluorescent Lighting
  • Meet new requirements on 8 4 lamps
  • Consider using newer T-8 or T-10, T-5
  • Use electronic ballast
  • Use of retrofit reflectors in fixtures not
    originally equipped with built-in reflectors
  • Replace U-tubes with straight tubes

15
Ballast Factor
  • Ballast an electrical device that supplies
    sufficient voltage to start the flow of arc
    current in a fluorescent lamp, and then regulates
    the proper arc current to the lamp.
  • Ballast Factor a measure of the actual lumen
    output for a specific lamp-ballast system
    relative to the rated lumen output measured with
    a reference ballast under ANSI test conditions
    (open air at 25 C 77 F).

16
Lighting Examples
17
Lighting Examples
18
Lighting Examples (cont.)
Esthetics to set the scene
19
Lighting Examples (cont.)
Task Lighting
Wall Washing
20
Lighting Examples (cont.)
Partitions to Intercept the light
21
Lighting Examples (cont.)
Efficient Lighting Uniform Lighting
22
Lighting Examples (cont.)
Lighting Location
23
Best Use of Light is NO LIGHT
24
Example T-8 ReplacementConsider the following
Old New lamping system
  • Actual System
  • - Offices lighting with 360 Fluorescent fixtures
  • - Operates for 14 hrs/day, 5 day/week 3640
    hr/yr
  • - Each fixture draws 188Watts with 4 standard 40W
    cool-white 40 W Fluorescent lamps (_at_2 each).
    They have 2 standard magnetic ballasts that draw
    14 W each.
  • Proposed New System
  • Each fixture now draws 132 W with 4 Tri-phosphor
    T8 32 W fluorescent lamps and 1 electronic T-8
    instant start ballast (4W)
  • Problem Compute the Demand, Energy, and Cost
    avings
  • Assume 7/kW/mo and 0.05/kWh and any other
    one

25
Solution
26
Lighting Control Technologies
  • ON/OFF snap switch
  • Timers and Control systems
  • Solid-State Dimmers
  • Dimming electronic Ballasts
  • Occupancy Sensors
  • Daylighting Level Sensors

27
When Where to use Them
28
Other Lights
29
Lighting Examples (cont.)
Optical Aids
30
EXIT Lights
  • Incandescent
  • Fluorescent
  • LED
  • Electroluminescent
  • Self-luminescent

31
Selecting Lighting Components
  • Ballasts
  • - Function
  • - Types
  • - Properties
  • - Problems with ballasts
  • - Disposal of ballasts

32
  • Ballast Function
  • - Provide starting Voltage
  • - Limit current once lamps ignite
  • - Provide proper power quality for lamps
  • Types of Ballasts
  • - Preheat, Rapid start, Instant start
  • - Premium Magnetic, Hybrid Magnetic/Electronic
  • - Electronic, Dimming
  • Properties of Ballasts
  • - Ballast Factor, Power Factor
  • - Harmonic distortion, Efficiency

33
Electronic Ballasts
  • Available for rapid start or instant start
  • Operate at 20 to 40 kHz, increase system efficacy
    15 20
  • Models available to run 1 4 lamps
  • Can operate lamps in series or Parallel
  • Reduced weight, quieter operation reduced lamp
    flicker

34
Dimming Electronic Ballasts
  • Most are 2 Level 50 or 100
  • Full Range dimming 1 100
  • Standard Dimming electronic 10 100
  • New Hi/Lo Dimming electronic 50
  • Example 400 W to 256W

35
Problems with Ballasts
  • Premature failure
  • Electromagnetic Interference
  • Noise and Harmonics
  • Disposal of Ballasts
  • Old units have PCBs in them (toxic)
  • State and federal regulations apply

36
Occupancy Sensors
  • Passive infrared sensors
  • Ultrasonic sensors
  • Dual technology sensors
  • Microwave sensors
  • Motion sensors
  • Temperature sensors

37
Avoiding Light Retrofit Pitfalls
  • General Suggestions
  • - Lowest first cost systems are not usually the
    lowest
  • life-cycle cost systems
  • - Shop around for best price
  • - use formal set of written specifications
  • - Decide in advance your purchasing criteria
  • Test Systems
  • - If possible always test first
  • - Use a mockup
  • - Request employees comments and evaluations
  • - Determine light quantity and quality to be used

38
HVAC Interactions
  • Usually, all energy that goes into lighting
    system becomes heat that must be removed by the
    HVAC system
  • Almost all newer buildings are air conditioned
    all year round at least in the core areas
  • For example, in Florida around 25 of additional
    savings in AC are associated with lighting energy
    efficiency improvements

39
Employee Acceptance
  • In general do not mix lights of different types
    or colors. For example, MH and HPS in the same
    area (indoors )
  • Make all lighting changes in an area at one time
  • Lighting is very subjective, so it is worthwhile
    to try to prevent employee criticism of the
    lighting changes

40
Power Quality Issues
  • Harmonics - How to tell if you have them
  • How lighting contributes to power quality
    problems
  • How other equipment contributes to problems
  • How to help reduce the impact of harmonics

41
Maintenance The Good Bad
  • Lighting
  • - Group relamping (lower cost)
  • - Clean fixtures (often)
  • - Write a lighting Maintenance Policy
  • - Lighting upgrades must consider Maint.
  • Light Loss Factors
  • - Lamp Ballast failures
  • - Lamp lumen depreciation
  • - Luminaire dirt depreciation

42
Maintenance Planning
  • Define existing conditions
  • Establish a relamping interval
  • Predict light loss factor
  • Develop a maintenance method
  • Budget for maintenance
  • Write a lighting maintenance policy
  • Implement the strategy

43
Economics of Group Relamping
  • Typically group relamp at 70 of rated life
  • Spot relamp cost around 6.00/lamp
  • Group relamp cost is about 1.50/lamp

44
The Coefficient of Utilization
  • The CU is a measure of how well the light coming
    out of the lamps and the fixture contributes to
    the useful light level at the work surface
  • It may be given, or you may need to find it
  • - Use Room Cavity Ratio to incorporate room
  • geometry
  • - Use Photometric chart for specific lamp and
  • fixture

45
Room Cavity Ratio (RCR)
  • RCR 2.5 ? h ? (Perimeter/Area)
  • Or, if the room is rectangular
  • RCR 5 ? h ? (L W)/(L ? W)
  • Where L room length
  • W room width
  • h lamp to top of working surface height

46
Example
  • Find the RCR for a 30ft by 40ft rectangular
  • room with a ceiling height of 9.5 feet
  • Solution
  • h 9.5 ft 2.5 ft 7 ft
  • RCR 5 ? h ? (L W)/(L ? W)
  • 5 ? 7ft ? (30ft 40ft)/(30ft ? 40ft)
  • 2.04

47
Photometric Chart
48
Example
  • Find the Coefficient of Utilization for a 30ft by
  • 40ft rectangular room with a ceiling height of
  • 9.5 ft, a ceiling reflectance of 70 and a wall
  • reflectance of 50 using the photometric chart

Solution The RCR from before was 2.04. Using
RC70 and RW 50, the CU is found to be CU0.81
49
Fundamental Law of Illuminationor Inverse Square
Law
  • Where,
  • E Luminance in foot-candles
  • I Luminous intensity in lumens
  • d Distance from light source to surface area

50
Example
  • In the production area of a facility you notice
    that you can lower the lights. Currently
  • there are 49 compact fluorescent lamps of 150W
    each. These lamps are currently
  • suspended from the ceiling approximately 22 feet
    from the floor. You suggest a
  • new height of 15 feet instead. What is the
    reduction on the number of lamps ?
  • what are the kW, kWh, and Cost savings ?
    Consider 8.5/kW-mo 0.05/kWh.
  • Solution
  • 150W compact fluorescent lamps produce an average
    of 24,500 lumens when lit.
  • E Iexisting / (dexisting)2 Iproposed
    / (dproposed)2
  • 24,500 lumens / ( (22ft)2)
    Iproposed / ( (15 ft)2)
  • Consequently,
  •  Iproposed (24,500 lumens) (225 ft2)
    / (484 ft2) 11,389 lumens

51
Example (cont.)
  • Facility requires lamps that provide 11,389
    lumens per lamp at a height of
  • 15 ft. Lowering these compact fluorescent lamps
    and increasing lamp
  • wattage, client will not need as many lamps as
    they currently have.
  • Estimate of the proportion of lamps needed. We
    use the following ratio
  • Factor 11,389 lumens/24,500 lumens 0.465
  • This ratio is used to estimate the number of
    lamps required at 15 ft.
  •  
  • New Number of Lamps Current number of lamps
    ? Factor
  • 49
    0.465 23 lamps

52
Example (cont.)
  • Demand Reduction (DR)
  • DR (BF ? Nexist? Watts ) ? (BF ? Nprop ?
    W ) ? (1kW / 1,000 W)
  •  
  • Where, BF Ballast Factor, 0.95 W
    Lamp wattage, 150 Watts
  •  
  • Therefore
  • DR 0.95 ? 49 ? 150Watts ? 0.95 ? 23 ?
    150Watts ? (1 kW / 1,000 W)
  • 3.7 kW
  •  
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