Using new, lower-cost technologies, light-emitting diodes (LEDs) may be poised to compete with traditional sources in yet another major lighting market.
Cree Inc. has developed the XSP Series of streelights that employ new optics, drivers, and housings to double its lumens per dollar. Cree hopes to use this series to compete more directly with sodium vapor technology providers. This could represent another big step forward for LED technology, which has already made inroads in televisions, aircraft, automobiles, signage, displays, and other applications.
Cree's XSP Series streetlights use five optical assemblies. Earlier ones used 80 to 120. (Source: Cree Inc.)
"By figuring out a different way to assemble the optics, we've made it a lot less expensive," Gary Trott, vice president of market development for Cree, told us. "The LEDs also have more light coming out of them, so we don't need as many."
The biggest reason for the higher lumens-per-dollar figure is the NanoOptic Precision Delivery Grid configuration, which dramatically reduces the number of optical assemblies that must be seated atop the LEDs, Trott said. In contrast with earlier generations of the company's streetlights, which used between 80 and 120 optical assemblies, the new streetlights employ just five. "That's a big contributor to our ability to boost the number of lumens per dollar."
Cree's new streetlights could reportedly sell for as little as $200, depending upon volume and power. The company says the new streetlights will use 50 percent less energy and last three times longer than sodium vapor lamps.
Beth: Incandescents have long been optimized to work on our common 110V power supplies, and therefore need no extra circuits to adapt the input source to the output. LEDs are more complicated. With an LED, you need to understand the input source and its variability. On the output side, you need to understand optical requirements and the amount of lumens you want to generate. All of this will be worked out over time, though, as more LED apps pop up.
The energy saving of the LED streetlights is impressive. We had a different issue with LED parking lot lights. Unlike the incadescent lights which were too hot for bird nests, the LED lights did not have same heat which allowed a good spot for birds to nest. With no solution from the manufacturerer, we returned the lights for credit and re-installed the old lights. This was a while ago, and I hope that this potential problem has been addressed.
Why is it nothing in the article speaks to the bottom line. Efficiency, usability and durability. Sodium lights can have efficiency of 200 lumens/watt. LEDs have 100. See wikipedia.
LEDs have wideband, selectable wavelength. Sodium is narrow, harsh and often color-blinding.
Newest LEDs and arrays have unproven durability and must be housed properly to account for icing conditions.
Not showstoppers but definitely considerations. A recent energy survey of my mom's residence resulted in all incandescent bulbs replaced with slow, low-lumen CFLs 18 months ago. I have since reverted half of them back to hot, quick-on, high watt and useable halogens. Solar arrays on the roof keep her feeling green. Not one size fits all for LEDs either. LEDs work great for landscape and atmosphere lighting. For handiwork and reading, give me a big bright soft-white every night or day.
As engineers and designers, we need to stop chasing fads and letting marketers yank us around. Just the facts, ma'am, just the facts.
Beyond the cost barrier, what have the downsides been for a broader array of LED applications? I've run into plenty of downsides with CFL lights, which frankly aren't compelling enough to justify the added expense and the potential energy savings.
LED Street Lights have gained ground and are being implemented right here in Stamford and Greenwich CT. LED lighting is certainly the wave of the future. However, only by educating the public to the true savings of LED bulbs will they become commonplace. The initial cost can sometimes seem high. It is only after comparing the cost vs savings over time do you see the real benefit of LED lighting solutions. I commend all cities and towns that are reducing costly energy consumption by utilizing energy efficient solutions.
tekochip; I have heard the same complaint. In the northern states in winter the snow can build up on traffic lights and obscure them. With incandescents the waste heat would help clear the snow.
Beth, the laptop I am using now had LEDs for backlighting for the disply. It helps the battery last much longer. LEDs in this application replace EEFL lights, which are fairly effecient compared to incandescent.
As the price comes down they will replace other types of bulbs. Just the much longer lifetime helps. Even at home, not having to replace bulbs is a plus. For something like streetlamps bulb replacement is a very costly thing. This is a good trend.
Incandescent replacements have some fantastic advantages. I recently replaced the landing light in my 172 with an LED lamp. The constant vibration and heat make incandescents a poor choice for the cowl mounted landing light location in older Cessna's, but that's the only technology that was available at the time. Considering the promise of greatly improved life and a current draw that's nearly 1/10 of the original, the LED lamp was an ideal choice. Since the landing light only pulls a couple of amps and has such great life, I leave it on all the time.
The only disadvantage I've seen to incandescent replacements is the waste heat from traffic lights. Now there's not enough heat to melt the snow off here in blustery Chicago.
By experimenting with the photovoltaic reaction in solar cells, researchers at MIT have made a breakthrough in energy efficiency that significantly pushes the boundaries of current commercial cells on the market.
In a world that's going green, industrial operations have a problem: Their processes involve materials that are potentially toxic, flammable, corrosive, or reactive. If improperly managed, this can precipitate dangerous health and environmental consequences.
With LEDs dropping in price virtually every year, automakers have begun employing them, not only on luxury vehicles, but on entry-level models, as well.
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