2012 January 07 Saturday
Lighting Trade-Offs with LEDs, CFLs, Halogens

Due to both technological advances and regulatory and economic drives toward greater energy efficiency decisions over light bulb choices have gotten much more complex - unless you just ignore the complexity and grab something off the shelf. But if you like the maximize the quality of your light bulb buying decisions then a review on light bulbs by Bob Tedeschi in the New York Times is a good place to start.

The quality of L.E.D. light, even the “soft white” types, is noticeably cooler than that of halogens or C.F.L.’s. And because most L.E.D.’s are unidirectional, they work well for recessed lights or lamps that spotlight artwork. But this single-focus nature is a problem for standard shaded lamps. The packaging of Sylvania’s Ultra A-Line L.E.D. suggests that it’s suitable for a shaded lamp, but when I tried it in a lamp in my living room, the top half was lit, while the bottom saw little light.

However, Sylvania will release an omnidirectional L.E.D. this winter, and two manufacturers are now making them. When I tried them — G.E.’s Energy Smart L.E.D. and the Philips AmbientLED — they lighted up both the top and bottom of my lamp. The Philips bulb was softer than G.E.’s — so much so that I now have two of them gracing my living room.

LEDs, while still expensive, have come down far enough in price that their life expectancies (20+ years in most cases) make them an attractive choice. It is always good to find more areas of one's life where one can basically deal with a problem once and then not think about it for a long time.

the article is not a sales job for uniform use of LEDs. He does a good job of explaining the trade-offs for different rooms of the house and purposes. Worth a read if you want to make smarter lighting decisions.

One interesting factoid from the article brings up a new way (at least I haven't thought of it) to save energy: rejuvenate eyes.

“Fifty-year-olds need twice as much light to read something as well as a 20-year-old,” Mr. Bernecker said. “It’s a sad story.”

Think about it. If we could replace aged lens and send in stem cells and gene therapies to repair eyes we would have in electric lighting costs. Plus, we've save even more in costs of optometry and eye glasses. The gain in convenience (no more "where are my glasses") would be considerable as well.

By Randall Parker    2012 January 07 11:09 AM   Entry Permalink | Comments (10)
2011 July 05 Tuesday
LED Will Not Wipe Out Fluorescent Lighting?

Light Emitting Diodes (LEDs) are expected by some observers to become so cheap, efficient, and long-lasting that they will displace fluorescent light bulbs. Francis Rubinstein, a scientist in the Lawrence Berkeley National Laboratory's Environmental Energy Technologies Division, says the imminent death of fluorescent lighting at the hands of LEDs has been exaggerated.

"The common view," says Francis Rubinstein, a scientist and energy-efficient lighting expert at Lawrence Berkeley National Laboratory's Environmental Energy Technologies Division, "is that LED lighting is replacing fluorescent lighting with the same inevitability that mammals replaced dinosaurs as the dominant large life forms on Earth."

...

But wait, says Rubinstein, who has been delivering a talk to lighting industry audiences titled "Why Fluorescent Lighting Isn't Dead." He believes that modern fluorescent lighting will continue to dominate the general lighting market and that solid-state LED lighting will coexist in the marketplace with fluorescent lighting for some time to come. Rubinstein sees a near-term future in which LED and fluorescent lighting coexist in hybrid systems that will be more adaptable to the lighting needs of a wide variety of residential, commercial, and industrial building types and space configurations.

Established technologies often last way longer than expected. Look at the 4 stroke internal combustion engine (ICE). The Wankel rotary failed to displace it. Hydrogen fuel cells are still a long way off. Previous attempts to commercialize electric vehicles have failed. This time around high oil prices and advances in battery tech suggest better prospects for EV. But while projections for electric vehicle sales in 2020 vary over a wide range none of the estimates I've found have EVs replacing the ICE from the top spot by 2020. It is hard to unseat the incumbent because incumbent technologies generate huge cash flows that help fund refinements and improvements to the incumbent's design and manufacture.

In the comments of Green Tech Media's coverage of this report you can read a few people who work in the lighting industry explaining obstacles to more widespread uptake of LEDs. Cost is not the only concern. Color quality, existing fixtures designed for fluorescents, and continued improvements in fluorescent technologies all slow down the adoption of LEDs.

By Randall Parker    2011 July 05 12:04 AM   Entry Permalink | Comments (15)
2009 December 02 Wednesday
Energy Efficient Light Bulb Manufacturing Energy Usage

German lighting company Osram finds that the energy used in making light bulbs is too little to affect total lifetime energy usage calculations. Compact fluorescents and LEDs really do save as much energy as their labeled wattages suggest.

The energy used during the manufacturing phase of all lamps is insignificant — less than 2 percent of the total. Given that both compact fluorescents and LEDs use about 20 percent of the electricity needed to create the same amount of light as a standard incandescent, both lighting technologies put incandescents to shame.

That's a great energy savings return on energy invested. Definitely low-lying fruit for anyone who wants to cut their energy bills who doesn't mind the light from CFLs or LEDs.

If you shop around on the internet you can find places that sell CFLs with different color distributions. Look for Kelvin numbers with lower numbers producing a yellower light and higher (4100K and up) producing a whiter light with more blue added. They also differ by Color Rendering Index. Perhaps a reader can describe better the differences to look for in CFLs?

Update: But a lot of CFLs do not perform as well as advertised.

Traditional incandescent bulbs, which are being phased out of British shops, lose just a fraction of their brightness by the time they stop working, but energy-saving ones lose 22 per cent of brightness.

The figures come from an in-depth report from E&T, the leading trade magazine published by the Institution of Engineering and Technology.

Buyer beware. Though I still expect CFLs to generate large net savings. Look for Energy Star rated bulbs as potentially higher quality.

By Randall Parker    2009 December 02 09:48 AM   Entry Permalink | Comments (40)
2009 July 05 Sunday
Incandescent Bulbs To Close Efficiency Gap With Fluorescents?

Here's a happy story for incandescent bulb lovers and also for those who just like to see innovation making things more efficient. Spurred by a US energy efficiency law that set standards for light bulb efficiency innovators are developing ways to make incandescents

The first bulbs to emerge from this push, Philips Lighting’s Halogena Energy Savers, are expensive compared with older incandescents. They sell for $5 apiece and more, compared with as little as 25 cents for standard bulbs.

But they are also 30 percent more efficient than older bulbs. Philips says that a 70-watt Halogena Energy Saver gives off the same amount of light as a traditional 100-watt bulb and lasts about three times as long, eventually paying for itself.

So this regulation for light bulb efficiency spurred a lot of innovation.

A company called Deposition Sciences is developing methods to increase efficiency and licensing the technology to light bulb manufacturers. One approach: reflect heat back onto the filament the heat gets converted into light. Other innovators are also finding ways to improve the efficiency of these bulbs.

The people who dread what previously seemed like an inevitable switch to fluorescents and LEDs are going to be happy to hear that the incandescents will survive.

By Randall Parker    2009 July 05 11:43 PM   Entry Permalink | Comments (59)
2008 February 02 Saturday
Hate Fluorescent And Dreading Incandescent Bulb Phase Out?

Writing in Slate Ron Rosenbaum captures a widely shared (including by me) hatred of fluorescent light.

Yes, the idiots in Congress, too torpid and ineffectual to pass a health-care bill for children, have busy-bodied themselves in a bumbling way with the way you light up your world. In December, they passed legislation that will, in practice, outlaw incandescent bulbs because they won't be able to meet the new law's strict energy-efficiency standards. The result: Between 2012 and 2014, incandescent bulbs will be driven from the market. Replaced by the ugly plasticine Dairy Queen swirl of compact fluorescent lights.

From a purely environmental perspective, this move is shortsighted. CFLs do use less energy, which is good. But they also often contain mercury, one of the most damaging—and lasting—environmental toxins. Not a ton of mercury, but still: A whole new CFL recycling structure will be required to prevent us from releasing deadly neurotoxins into the water table. CFLs: coming soon to sushi near you.

The compact fluorescent lights (CFLs) are supposed to replace the incandescent light bulb. But they've got major drawbacks. As Rosenbaum sees it, the real evil of flourescents is aesthetic.

But the greater crime of the new bulbs is not environmental but aesthetic. Think of the ugly glare of fluorescence, the light of prisons, sterile cubicle farms, precinct stations, emergency rooms, motor vehicle bureaus, tenement hallways—remember Tom Wolfe's phrase for the grim, flickering hallway lights in New York tenements: "landlords' haloes"?—and, of course, morgues. Fluorescents seem specially designed to drain life and beauty from the world. Don't kid yourself if you hope Hell is lit by fire. More likely fluorescents.

Yes, fluorescents. Buzzing, flickering, able to cause epileptic seizures in the susceptible, in addition to headaches and other neurological symptoms. Let's smash all the incandescent lights and replace their glowing beauty with the harsh anatomizing light of fluorescence. The flickering tinny corpse light of bureaucracies and penal institutions.

I'm more down on them due to their distracting effect. I have enough interruptions to my concentration as things stand without the mental fatigue and distraction caused by flicker.

In the book of Genesis God did not say "let there be flickering".

The new CFLs pulse faster than their ancestors, so the flickering is less perceptible, but at some level, it's still there. CFL manufacturers may be right that the new bulbs are an improvement, but there is still something discontinuous, digital, something chillingly one-and-zero about fluorescence, while incandescent lights offer the reassurance of continuity rather than an alternation of being and nothingness. If I remember correctly, the line from genesis was "Let there be light," not "Let there be flickering."

I bought some CFLs several years ago to use in places I spend little time in. But my light fixtures in most of those places can't fit the CFLs.

Dan Neil of the Los Angeles Times shares Rosenbaum's lack of enthusiasm for fluorescents and also thinks LED lights are not good substitutes either.

As a good liberal, I’m ready to embrace, and pay for, more efficient lighting. And yet, I’m already feeling what might be called Edison nostalgia. Even a bare bulb hanging from a wire is a thousand times more bewitching, more jocund and welcoming than a CFL screwed into the most arty fixture featured in Wallpaper magazine. The light from a CFL—stark and shadowless and overcorrecting—is a scold: Why haven’t you dusted? Why haven’t you taken better care of your skin? (This is the well-known public lighting effect.) LEDs, by their very nature, produce a single frequency of light, a sliver of the visible spectrum. In the case of “white” LEDs that would replace the common bulb, they are actually a ghastly white shade of blue, and that’s why everyone looks a touch cyanotic under them. The quality of light from these instruments will get better, but they only can approximate—only counterfeit—the warm, wide-spectrum glory of a filament that radiates across the visible spectrum and beyond.

But on FuturePundit there's the obligatory "but can't technological advances solve all problems?" angle to any story. Some Turkish researchers might have found a way to make LED light more acceptable.

Topping LEDs with a coating of carefully tuned nanocrystals makes their light warmer and less clinical, a new study shows. The researchers argue this is a must for energy-efficient LED lights to make headway in the commercial market.

...

To accomplish this, Hilmi Volkan Demir and colleagues at Bilkent University in Ankara, Turkey, coated blue LEDs with a layer of nanocrystals. These crystals are made from a core of cadmium selenide with a surrounding layer of zinc sulphide.

The crystals absorb some of the LED's blue output and emit their own red and green light. That combines with the remaining blue light to produce a soft white glow.

A New York Times panel looked at 21 alternatives to incandescents and found most of the compact fluorescent lights (CFLs) disgusting. But they liked some of the LED and halogen choices and even found a few CFLs acceptable.

Another object of excitement was the Pharox bulb (upscalelighting.com) from Lemnis Lighting, which uses a light-emitting diode, or L.E.D. This technology, which works by illuminating a semiconductor chip, is more efficient than compact fluorescent lighting. But because L.E.D.'s emit directional rather than diffuse light, they are typically implanted in flat surfaces like walls or light panels.

Not all the bulbs were met with negativity. Panelists favored the light cast by halogen bulbs (including the Daylight Plus and the BT15 from Sylvania, and G.E.'s Edison 60), which last twice as long as incandescents, requiring less energy for the production and distribution of replacements, and are therefore more efficient.

One halogen model, the Philips Halogena, was not only pleasing to the eye - "nice, soft, golden light" one panelist said - but efficient enough to meet the criteria of the new energy bill.

...

The n:vision TCP Home Soft White, for example, was deemed "a warm pleasant light." The TCP Spring Light/Soft White was "almost warmer than incandescent," one person said. And the MaxLite SpiraMax was generally liked.

That LED Pharox bulb costs $59. Not exactly cheap.

Since we will have halogen and LED alternatives the death of incandescent bulbs won't force us to use CFLs. LED costs are falling and moving into wider spread use on cars. That bodes well. But as we near incandescent phase-out dates if LEDs and halogens aren't looking like acceptable and affordable alternativs you might want to lay in a few year supply of incandescents to provide more time for the non-fluorescent alternatives to improve.

Update: Brendan Koerner defends CFLs.

The irony of CFLs is that they actually reduce overall mercury emissions in the long run. Despite recent improvements in the industry's technology, the burning of coal to produce electricity emits roughly 0.023 milligrams of mercury per kilowatt-hour. Over a year, then, using a 26-watt CFL in the average American home (where half of the electricity comes from coal) will result in the emission of 0.66 milligrams of mercury. For 100-watt incandescent bulbs, which produce the identical amount of light, the figure is 2.52 milligrams.

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The last, desperate swipe at CFLs—as elucidated by the Lantern's colleague last week—is that their light is cold and dreadful. Perhaps this was true in years past, but the Lantern just doesn't see it anymore: In a recent test, Popular Mechanics rated CFL light as far superior to that produced by incandescent bulbs.

You can always try one of the higher rated CFLs and judge for yourself. But I continue to hate the workplace long tube fluorescents that I come across.

By Randall Parker    2008 February 02 07:37 PM   Entry Permalink | Comments (42)
2005 October 25 Tuesday
Quantum Dots Make LEDs Full Spectrum Light Sources

The days of Edison's light bulb are numbered.

Take an LED that produces intense, blue light. Coat it with a thin layer of special microscopic beads called quantum dots. And you have what could become the successor to the venerable light bulb.

The resulting hybrid LED gives off a warm white light with a slightly yellow cast, similar to that of the incandescent lamp.

Until now quantum dots have been known primarily for their ability to produce a dozen different distinct colors of light simply by varying the size of the individual nanocrystals: a capability particularly suited to fluorescent labeling in biomedical applications. But chemists at Vanderbilt University discovered a way to make quantum dots spontaneously produce broad-spectrum white light. The report of their discovery, which happened by accident, appears in the communication "White-light Emission from Magic-Sized Cadmium Selenide Nanocrystals" published online October 18 by the Journal of the American Chemical Society.

In the last few years, LEDs (short for light emitting diodes) have begun replacing incandescent and fluorescent lights in a number of niche applications. Although these solid-state lights have been used for decades in consumer electronics, recent technological advances have allowed them to spread into areas like architectural lighting, traffic lights, flashlights and reading lights. Although they are considerably more expensive than ordinary lights, they are capable of producing about twice as much light per watt as incandescent bulbs; they last up to 50,000 hours or 50 times as long as a 60-watt bulb; and, they are very tough and hard to break. Because they are made in a fashion similar to computer chips, the cost of LEDs has been dropping steadily. The Department of Energy has estimated that LED lighting could reduce U.S. energy consumption for lighting by 29 percent by 2025, saving the nation's households about $125 million in the process.

Doesn't that amount of savings seem small? Does the United States really spend such a small amount of money on incandescent light electricity?

LEDs are more efficient because they do not emit in the infrared.

Of course, quantum dots, like white LEDs, have the advantage of not giving off large amounts of invisible infrared radiation unlike the light bulb. This invisible radiation produces large amounts of heat and largely accounts for the light bulb's low energy efficiency.

The breakthrough came accidentally and was the result of making quantum dots smaller than they are usually made.

Bowers works in the laboratory of Associate Professor of Chemistry Sandra Rosenthal. The accidental discovery was the result of the request of one of his coworkers, post-doctoral student and electron microscopist James McBride, who is interested in the way in which quantum dots grow. He thought that the structure of small-sized dots might provide him with new insights into the growth process, so he asked Bowers to make him a batch of small-sized quantum dots that he could study.

"I made him a batch and he came back to me and asked if I could make them any smaller," says Bowers. So he made a second batch of even smaller nanocrystals. But once again, McBride asked him for something smaller. So Bowers made a batch of the smallest quantum dots he knew how to make. It turns out that these were crystals of cadmium and selenium that contain either 33 or 34 pairs of atoms, which happens to be a "magic size" that the crystals form preferentially. As a result, the magic-sized quantum dots were relatively easy to make even though they are less than half the size of normal quantum dots.

After Bowers cleaned up the batch, he pumped a solution containing the nanocrystals into a small glass cell and illuminated it with a laser. "I was surprised when a white glow covered the table," Bowers says. "I expected the quantum dots to emit blue light, but instead they gave off a beautiful white glow."

"The exciting thing about this is that it is a nano-nanoscience phenomenon," Rosenthal comments. In the larger nanocrystals, which produce light in narrow spectral bands, the light originates in the center of the crystal. But, as the size of the crystal shrinks down to the magic size, the light emission region appears to move to the surface of the crystal and broadens out into a full spectrum.

As all matter of materials get made at smaller sizes more interesting, unexpected, and useful behaviors of materials will be found.

By Randall Parker    2005 October 25 10:54 AM   Entry Permalink
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