Developments in LED lighting
31 Dec 08 | Environment, Solar ElectricAs part of a general trend toward more efficient energy use, LED (AKA solid state) lighting shows promise. From EE times.com:
White organic light-emitting diodes (OLEDs) are already producing more light per watt than incandescent bulbs, according to engineering professor Stephen Forrest, but it is trapped inside the device. By fabricating a tandem system of grids and micro lenses on a white OLED, the device can achieve a brightness of over 70 lumens per watt, compared with 15 lumens for incandescent bulbs–almost as much as fluorescent tube lights (90 lumens).
And from Scientific Blogging:
Current white LED’s require a substrate made of sapphire and an additional mirroring layer to reflect light that would otherwise be lost… Researchers at Purdue University have found one method of significantly reducing the cost of a white LED by eliminating the expensive layer of sapphire. Instead, they used silicon as the substrate (the material the diode is printed on) and zirconium nitride as the reflector.
And from RPI:
Solid-state lighting that replaces incandescent and fluorescent bulbs with light-emitting diodes can reap enormous savings in cost, natural resources and pollution, according to a recent study by Rensselaer Polytechnic Institute. RPI’s Troy, New York-based Smart Lighting Engineering Resource Center claims that over the next 10 years savings of more than $1.8 trillion will eliminate the need to burn almost a billion barrels of oil in power plants that would otherwise produce 10 gigatons in the carbon dioxide emissions.
Lighting accounts for 22% of all electrical consumption in the United States. If even half of the reduction claimed in the RPI report is realized, a significant step has been made toward reducing pollution and increasing energy efficiency. For most people, the current color rendition of solid state lights (SSL) is harsh with too much blue light used. This problem is being worked on.
Further, SSL systems are great companions to off grid PV systems that can use DC power distribution. In an AC (alternating current) system, losses come from inverters, power supplies, and the LEDs themselves. In a DC (direct current, e.g. 12 or 24 volt) system, the only losses are the LEDs.
Look for more developments in SSL in the near future.
Tags: energy efficiency, Environment, LED lights, off grid, SSL



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