1. 1
Fundamentals of Energy Efficient Lighting
Presented By:
Ken Currie, PhD, P.E.
July 17, 2013

2. 2
Building Lighting Energy

3. 3
Lighting Type First Cost

4. 4
Lighting Type Life Cycle Cost

5. 5
Lighting Energy Efficiency

6. 6
Efficient Lighting

7. 7
Amount of Light

8. 8
Other Considerations

9. 9
Light & Color

10. 10
Color Temperature
Color Temperature is noted in
degrees Kelvin* or °K
3,000°K - Warm White
3,500°K - Neutral
4,100°K Cool White
* The Kelvin Scale is defined as Celsius plus 273.

11. 11
Color Temperature Definition
• the electromagnetic radiation emitted from an ideal black body
• 1,700 K Match flame
• 1,850 K Candle flame, sunset/sunrise
• 2,700–3,300 K Incandescent lamps
• 3,000 K Soft White compact fluorescent lamps
• 3,200 K Studio lamps, photofloods, etc.
• 3,350 K Studio "CP" light
• 4,100–4,150 K Moonlight
• 5,000 K Horizon daylight
• 5,000 K tubular fluorescent lamps or Cool White/Daylight CFL
• 5,500–6,000 K Vertical daylight, electronic flash
• 6,500 K Daylight, overcast
• 5,500–10,500 K LCD or CRT screen
• 15,000–27,000 K Clear blue poleward sky

12. 12
Typical Color Temperatures
Incandescent ……... 2,750°K – 3,400°K
Fluorescent ……….. 2,700°K – 6,500°K
Mercury vapor ….. 3,300°K – 6,000°K
Metal Halide ……… 3,000°K – 4,300°K
High Pressure
Sodium …………...... 1,900°K – 2,200°K
Induction …………… 3,000°K – 4,000°K

13. 13
Color Rendering Index (CRI)
Color Rendering Index is a scale
from 0-100 that indicates the
accuracy with which a lighting
source can reproduce colors. The
higher the CRI value the more
accurate the color reproduction.

14. 14
Color Rendering Index (CRI)
Typical high CRI values: 80 to 90
Typical good CRI values: 65 to 80
Typical poor CRI values: <65
Note: The CRI for standard Low Pressure
Sodium lamps is extremely poor.

15. 15
Typical CRI Values
Incandescent …………….. 100
Fluorescent ………………. 60 - 90
Mercury vapor …………….15 - 30
Metal Halide ……………… 60 - 90
High Pressure Sodium ….. 10 - 60
Low Pressure Sodium ….. Negative
Induction ………………….. 85
LEDs……………………………. 30 - 60

16. 16
Lamp Life Comparison

17. 17
Light & Distance

18. 18
Light & Distance
The lighting level drops off as the
square of the distance.
E = I/d2
Where:
E = Illuminance (footcandles or lux)
I = Intensity of lighting in Candelas
D = Distance from the source

19. 19
Light & Distance
Therefore, even small changes in the
mounting height of a luminaire can
have a significant impact on the
lighting level.

20. 20
Lighting Levels
• Specific tasks to be performed
• Time required for each task
• Speed and accuracy
• Age of occupants
• Safety and security
• Aesthetics
• System operating cost

21. 21
Lighting Sources

22. 22
Lighting Sources

23. 23
Sources Efficacy
0
20
40
60
80
100
120
140
160
Tungsten LEDwarm Mercury Vapor LEDcool Fluorescent Induction Metal Halide HPS LPS
Lumens/Watt
Lighting Source Efficiency

24. 24
Source Efficacy

25. 25
Reflectors

26. 26
Reflectors
• Reflectors allow the user to direct most of the
light downward toward surfaces of interest
instead of lighting the ceiling.
• Reduce electric consumption by reducing the
number of lamps required for desired light
output.
• 3 Types (Reflective Efficiency)
– Standard Aluminum Reflector (86%)
– Reflective White Paint (91%)
– Enhanced Specular Aluminum (95%)

27. 27
LED Lamps – Efficacy

28. 28
Basic Principles of Lighting Energy Management
1. If you don’t need it, turn it off
- Employee Awareness, Sensors,
Timers, Photocells, Timed Switches,
Energy Management Systems, etc.
2. Proper maintenance
- Group cleaning and relamping

29. 29
Basic Principles of Lighting Energy Management
3. Enhanced lighting control
- Photocells and occupancy sensors
4. More efficient sources
- Electronically ballasted fluorescent fixtures,
- Compact fluorescents
- Induction lamps
- Light emitting diodes (LEDs)

30. 30
Comparisons & Case Studies

31. 31
Incandescent Upgrades

32. 32
Case 1: Manufacturer

33. 33
Case 1: Manufacturer

34. 34
Case 1: Manufacturer

35. 35
Case 2: Automotive Components Manufacturer
Electric Rates: Usage: $.040/kWh Demand: $0.0/kW
Operating Hours of Fixtures: 8,760 hours/yr
Background:
(31) Exit fixtures are equipped with (2) 20-watt lamps each
Power Rating: 40-watts
Annualized Maintenance Cost per fixture: $25.81
Recommendation:
Replace with (31) LED exit fixtures, each with (2) 2-watt LED lamps
Power Rating: 4-watts
Annualized Maintenance Cost per fixture: $9.32

36. 36
Savings:
Usage: 9,776 kWh/yr $391 / yr
Demand: 13 kW/yr $0 / yr
Maintenance: $511 / yr
Total Savings: 902 / yr
Implementation Cost: $1,513
TVA Rebate: $978
Simple Payback Period: 1.68 years (0.59 yrs)
Case 2: Automotive Components Manufacturer

37. 37
Case 3: Auto Parts Manufacturer
Electric Rates: Usage: $.065/kWh Demand: $12.47/kW
Operating Hours of Fixtures: 8,736 hours/yr
Background:
There are (114) 400-watt metal halide fixtures throughout the facility
Power Rating: 450-watts/fixture
Annualized Maintenance Cost per fixture: $19.71
Recommendation:
Replace with (114) 220-watt T8 fluorescent fixtures
Power Rating: 220-watts
Annualized Maintenance Cost per fixture: $11.76

38. 38
Savings:
Usage: 229,058 kWh/yr $14,889 / yr
Demand: 314.6 kW/yr $3,924 / yr
Maintenance: $906 / yr
Total Savings: $19,719 / yr
Implementation Cost: $45,326
TVA Rebate: $22,906
Simple Payback Period: 2.30 years (1.14 yrs)
Case 3: Auto Parts Manufacturer

39. 39
Questions ???????????