Home » Is LED Lighting Really that Efficient and Can it Really Save that Much Money
In a study recently published by “Physical Review Letters”, a pair of MIT researchers have demonstrated that an LED can actually put out more optical power than the electrical power fed into it. Although this might on its face seem to violate the law of thermodynamics, in reality there is a phenomenon taking place which allows the LED to actually use the heat energy created by the LED to add to its photon production. The energy fed into their LED was so small, and the output so meager, they were able to take advantage of an LEDs’ tendency to become more efficient the lower the current fed into it. Although this demonstration of theirs doesn’t say anything important about potentially increasing the efficiency of LEDs used for general illumination, it does demonstrate the extreme efficiency potential with which LEDs operate.
In the real world, commercial grade LED lighting isn’t quite so efficient. In terms of general energy conversion to visible light output, today’s LEDs are capable of reaching up to 80% efficiency under perfect conditions, but for the most part average around 60-70%. Still, this is a significant improvement over incandescent bulbs which waste up to 90% of their energy as heat. LEDs even surpass metal halide for actual energy to light conversion, with metal halide converting about 50% of the electrical energy supplied into visible light. Of course, other factors come into play as well when considering real world applications. Incandescent, fluorescent, and HID light sources for example radiate light in all directions. This means that in order to project the maximum amount of their light output onto the targeted area, the fixture housing them must incorporate a reflector in order to redirect much of their output. The problem here however, is that even with an effective reflector, a lot of light is lost to fixture absorption. diffusion, and spillage. The end result is less light reaching the targeted area, adversely affecting how efficiently the fixture can illuminate a given amount of area.
Among the articles in the January 2021 issue of ISHN Magazine, we continue a series on whistleblowers, offer support for lone workers and provide an exclusive analysis of OSHA under the Biden Administration with commentary from a variety of experts.