Most Read
Most E-mailed
E-mail Article
Print Article![[Get Copyright Permissions]](http://license.icopyright.net/images/icopy-w.gif){kind=small}
Testing LEDs
How do LED component manufacturers test component lifetimes, since by the time 50,000 hours has passed, the component is already obsolete?
LED manufacturers use various proprietary testing techniques to accelerate LED failure, mostly using heat applied over thousands of hours. By understanding the failure mechanisms brought out through lifetime acceleration techniques over many successive product generations, manufacturers can accurately predict the lifetime of new products after only a few thousand hours of accelerated testing.
Numerous advances in white-LED brightness and efficacy have been made during the past 10 years. Arrays of packaged LEDs (each about ¼-inch on a side) can now be assembled to create various types of light fixtures, including fluorescent replacement fixtures troffer (for new builds) and troffer retrofit kits (for upgrading installed fluorescent troffers).
Given that LED fixtures can now replace fluorescents in their existing fixtures, how do they really compare? Today's LED can produce similar light output to a fluorescent, with dramatically improved lifetime and less energy required to operate. Benefits of LED lighting include:
- Able to last five to 10 times longer than fluorescents.
- Consume less energy while on.
- Contain no hazardous mercury.
- Are nearly unbreakable.
- Are free of annoying flicker and buzz.
- Are safer, operating on low voltage DC, with no glass or vacuum.
- Are fully dimmable.
It is estimated that using LEDs in the industrial/commercial market will save billions of dollars in maintenance and energy costs; reduce carbon emissions by 28 to 40 million metric tons annually; and potentially reduce spending on electricity by $125 billion over the next 20 years.
Energy costs have risen in the past five-plus years at roughly twice the rate of inflation nationwide. This has put pressure on operating profitability of U.S. corporations, particularly heavy energy users such as data centers or heavy manufacturing. Adding to this profitability pressure is the political pressure surrounding the country's energy security. In a 2006 article entitled, "Reducing U.S. Dependence on Middle Eastern Oil", Ariel Cohen, Ph.D., states:
"The United States is the largest oil importer in the world, bringing in 13.5 million barrels per day (mbd), which accounts for 63.5 percent of total U.S. daily consumption (20.6 mbd). Oil from the Middle East (specifically, the Persian Gulf) accounts for 17 percent of U.S. oil imports, and this dependence is growing.
There is a broad consensus in America, from the President to the man on the street, that this situation is detrimental to the country's economic health. In his 2006 State of the Union address, President George W. Bush said, "[We] have a serious problem: America is addicted to oil, which is often imported from unstable parts of the world." While recognizing the problem is laudable, however, little has been done to solve it."
Among the solutions to this problem are new technologies that reduce our energy consumption. LED lighting is a major player in this field; in U.S. commercial buildings, 25 percent of the total energy consumption is attributable to lighting. This is why the U.S. Department of Energy's National Renewable Energy Laboratory is pouring 60 percent of its Building research and development budget into solid-state LED lighting.
