Lighting: Fundamentals and Applications

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LightingFundamentals and Applications
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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

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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

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Principles of Efficient Lighting Design

• Meet target light levels
• Efficiently produce light
• Efficiently deliver light
• Automatically control lighting operation

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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

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Color Temperature Scale
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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)

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Some Typical Light Levels Needed
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Lamp Types

• Incandescent
• Halogen Incandescent
• Fluorescent
• Compact Fluorescent
• Mercury Vapor
• Metal Halide
• Compact Metal Halide
• High Pressure Sodium
• Low Pressure Sodium
• New Technologies

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Fixture Types

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

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Recessed Troffers

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

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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 300 lumen lamps in a
fixture, and assume a light loss factor of 70
with a coefficient of utilization of 75
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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

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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

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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).

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Lighting Examples
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Lighting Examples
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Lighting Examples (cont.)
Esthetics to set the scene
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Lighting Examples (cont.)
Task Lighting
Wall Washing
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Lighting Examples (cont.)
Partitions to Intercept the light
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Lighting Examples (cont.)
Efficient Lighting Uniform Lighting
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Lighting Examples (cont.)
Lighting Location
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Best Use of Light is NO LIGHT
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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

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Solution
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Lighting Control Technologies

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

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When Where to use Them
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Other Lights
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Lighting Examples (cont.)
Optical Aids
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EXIT Lights

• Incandescent
• Fluorescent
• LED
• Electroluminescent
• Self-luminescent

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Selecting Lighting Components

• Ballasts
• - Function
• - Types
• - Properties
• - Problems with ballasts
• - Disposal of ballasts

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• 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

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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

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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

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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

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Occupancy Sensors

• Passive infrared sensors
• Ultrasonic sensors
• Dual technology sensors
• Microwave sensors
• Motion sensors
• Temperature sensors

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Example
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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

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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

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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

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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

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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

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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

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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

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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

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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

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Example

• Find the RCR for a 30 by 40 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

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Photometric Chart
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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
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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