LED efficiencies: Apples and oranges
DOI: 10.1063/1.2970953
The item “White LEDs Poised for Global Impact” (Physics Today, December 2007, page 25 ) provides an interesting account of the use of LEDs in rural villages. Although the article correctly mentions that the energy efficiency of LED technology continues to improve, I found the efficiency comparison with fluorescent lights misleading, for two reasons. First, some manufacturers show their specs as lumens per watt of light output, while others show lumens per watt used by the LED. The former does not include power wasted as heat. Second, some comparisons are made using LED light that is concentrated in a narrow beam while the fluorescent lights are tested without fixtures.
More about the Authors
Bill Moran. (moran1@llnl.gov) Lawrence Livermore National Laboratory, Livermore, California, US .
