ppt - LightSavers

LEDs for Indoor
Scott Riesebosch
Chief Technology Officer
 CCT – what is it and why is it important for indoor
lighting? And why the extra “C”?
 CRI – what is it and why is it important?
 Are LED replacement lamps really a contender?
 Some reliability data points to consider
Colour Temperature (CT)
• Colour temperature refers to shades of white light, and is measured on the
Planck blackbody radiator scale (Black Body Locus, BBL)
• This scale measures the colour of a blackbody radiator (an ideal device with
perfect absorption and emission) at various Kelvin temperatures
Example blackbody radiators at
various color temperatures.
Correlated Color Temperature (CCT)
• Not all “white” light lies directly on the BBL
• CCT refers to the Plankian black-body radiator colour temperature (CT) that is
closest to the colour of the white light source
Relationship between CCT & CT
Examples of CCTs
Correlated Colour Temperature Effects
Color Rendering Index (CRI)
• CRI is an objective standard used to judge how well a light source renders
colours compared to a black-body radiator or daylight
• Incandescent bulbs are – by definition – equal to 100
• Eight pastel colours are measured under the test light source
• CRI measures how much these colours are affected by the light source
• Note: LEDs have fully saturated colour and actually pay a mathematical
penalty on the CRI system. Other standards for communicating colour are
under investigation …
CRI of common light sources
Light Source
Low pressure sodium
< 18
High pressure sodium
Warm white fluorescent tube
Typical Cool White LED
Daylight fluorescent tube
Metal halide
Typical Warm White LED
Halogen MR16
LED replacement lamp performance
 “Although there were a few exceptions, most of the lamps had
color quality attributes that were appropriate for replacing
halogen PAR lamps in most applications”
 “All of the LED PAR38 lamps tested offer substantial energy
savings compared to halogen PAR38 lamps, and some are more
efficacious than compact fluorescent or ceramic metal halide
 “It is reasonable to conclude that LED PAR38 lamps are (at least in
terms of performance) a viable option in most installations where
PAR38 lamps are used”
Source: USDOE Caliper Program Summary Report 20 November 2012
LED replacement lamp performance
 “Many of the Series 16 products would be an effective energysaving alternative to incandescent BR30 or R30 lamps. Further,
the efficacy and color characteristics are similar to or better than
directional CFL lamps”
 “Adding other factors such as dimmability and longer rated
lifetime makes LED BR30/R30 lamps the best solution for
replacing inefficient and soon-to-be regulated incandescent BR30
and R30 lamps”
Source: USDOE Caliper Program Summary Report 16 July 2012
LED replacement lamp ROI
 Can be under one year in applications of high usage, and
under 2 years in many applications
 Well suited to applications where maintenance cost is high
 Generally warranty is considerably longer than ROI
 Cost of ownership is a slam dunk in most applications
How much does it cost to change a
light bulb?
Reliability – can they hold up?
 Plenty of reliability data now available
 Advances in material science and deeper understanding of
failure modes that affect long term lumen maintenance and
colour shift over time
 Energy Star program requires 6,000 hours of testing at
elevated temperatures
 LED MR16 test lamps running continuously since August 2008
Reliability – can they hold up?
Reliability – can they hold up?
Reliability – can they hold up?
Reliability – can they hold up?
Reliability – can they hold up?
Over 44,000 hours
Thank you

similar documents