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Welcome to the Energy & Environment (E&E) Exchange, a blog dedicated to science and engineering topics that are (generally) related to energy and the environment. This blog is meant to encourage discussion about the challenges and possibilities surrounding sustainability through science and technology. The blog's owner, cheme_wordsmithy, is a former technical writer and engineering editor at IHS GlobalSpec, the company that powers CR4.

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23 comments

LEDs Made Brighter and Cheaper

Posted February 22, 2012 9:00 AM by cheme_wordsmithy
Pathfinder Tags: Brightness efficiency LED lighting

Many are already mourning the slow death of the incandescent bulb by its more efficient cousin, the compact fluorescent light (CFL). But most say LEDs (light emitting diodes) are the lighting of the future as soon as they can cut down the cost of production.

[LED vs. Incandescent vs. CFL - Source: relumination]

A startup company, Soraa, claims that it can make a new type of LED which is brighter and cheaper than current technologies.

The Process

The diodes are made of layers of semiconductor material, one has an excess of electrons and the next has a deficit. Impurities in the material are used to create the electron densities required for the electrons to move and generate light. Different colors are generated by using different semiconductor materials.

Blue and white LEDs (like those seen right - Source: keepandshare.com) are typically made by growing a thin layer of gallium nitride on a substrate (sapphire, silicon carbide, or silicon). The expense of gallium nitride has made using a thin layer the cheapest method, but results in reduced performance of the LED with increases in current density due to the mismatched crystal structure.

Soraa's process uses gallium nitride as the substrate. This reduces the mismatches ("dislocations") by a factor of 1,000. Those at the startup company say this reduction allows them to push 10x the current through the active layer material, resulting in brighter LEDs.

Overcoming Cost Barriers

Soraa claims the additional brightness allows the system to be designed cheaply enough to make up for added material costs. This is because Soraa's LEDs are the equivalent brightness of multiple traditional LEDs, requiring only one chip/diode. In addition, Soraa argues that the energy savings will make up the cost differential in under a year of use.

Gallium nitride is much more expensive than sapphire or silicon-based materials, which is the reason traditional designs used much less of it in the construction of the LED. Colin Humphrey, director of research at the University of Cambridge's Department of Materials Science and Metallurgy, says gallium nitride production can be long and difficult. He says it costs about $30 for a six-inch-diameter silicon wafer or two-inch-diameter sapphire wafer, and about $500 for a one-inch-diameter gallium nitride wafer.

On The Bright Side

Whether Soraa's claims will actually be cost effective will depend on how it does on the production line. With the ever-dropping cost of silicon, it may be hard for gallium-nitride based LEDs to compete.

[<-- Source: geek.com] But regardless of whether the products are successful, the new methods are evidence that solid state lighting technology is pushing forward. LEDs boast a number of advantages over other lighting sources, including significantly longer lifespan and surpassing efficiency. I think it's only a matter of time before they become the world's primary consumer lighting option.

Sources:

Madehow.com - LED

Technology Review - LEDs that Burn 10 Times Brighter

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#1

Re: LEDs Made Brighter and Cheaper

02/22/2012 2:56 PM

I think LED's would become less expensive if we can get away from AC power for lighting and use low voltage DC on a dedicated lighting circuit in the home. It seems most of the cost is because of the need to rectify AC to DC and drop the voltage + all the other electronic devices needed.

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#2
In reply to #1

Re: LEDs Made Brighter and Cheaper

02/22/2012 11:40 PM

Leds run tooooooo hot.

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#3
In reply to #1

Re: LEDs Made Brighter and Cheaper

02/23/2012 12:59 AM

And maybe having a 50W solar panel charging the dc circuit/battery, since LEDs take little power. A good thing even in case of power outage.

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#16
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Re: LEDs Made Brighter and Cheaper

02/26/2012 2:09 PM

Sounds like a great idea, especially since solar panels are coming down in price. Small home wind generators are also commonplace and cheap now. The amount of energy is so small though, I don't know if it is worth the trouble.

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#17
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Re: LEDs Made Brighter and Cheaper

02/26/2012 2:30 PM

If you have a spare alternator, some recycled steel pipes, a 200 liter steel drum and some connecting pieces you can build a 50 W to a 100W wind generator cheap and easy. Of course you need the skill but is still cheaper than other market stuff of cheaper than letting those pieces to rust in the rain.

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#18
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Re: LEDs Made Brighter and Cheaper

02/26/2012 4:53 PM

My wife would greatly prefer a nice looking professionally built one. It is on my wish list. We live on a one acre point between two well traveled roads. Aesthetics is a top priority. Thanks for the suggestion though. Truthfully my skills are rudimentary also. I would consider building solar panels because they are not as visible, on the Southern half of my roof. Don't know how much I could save though. Both would be great backups too. Just in case.

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#20
In reply to #18

Re: LEDs Made Brighter and Cheaper

02/28/2012 1:55 AM

Ron;

I have built several Eye Friendly - Sky Friendly High Efficiency Lighting Systems over the past few months using 3.2 volt LED's. I mount two LED's in series inside 1/4 inch PVC 40 caps. I use a 6 volt supply running good 2-18 thermostat wire through 1/2 inch conduit to string the assemblies in parallel. I mount the caps on the end of a 45 and a T. That makes them steerable and tough. I paint and hang the conduit under the eves and it lights the drive and sidewalks. With a little imagination you could make some great landscape lighting.

They light the path and don't blow out the stars.

They can be plugged in or powered up by solar/battery.

Really simple stuff to build, very high efficiency.

Send me your email address and if I ever complete my how to instructions I will send you a copy; but the first paragraph of this post tells you everything there is to it - which is not much.

I begin an around the world vacation next week and anticipate visiting several areas where "quiet" lighting might be appreciated. I am taking enough components to build a few sets with me. I hope I can make some connections at the local trade colleges while I travel. I would like to see this appropriate technonlogy adapted on a much wider scale.

This stuff works and works cheap.

Gavilan

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#4
In reply to #1

Re: LEDs Made Brighter and Cheaper

02/23/2012 1:23 AM

Look at the mains supply AC LEDS Acriche from Seoul Semiconductors Nice products and simple to.

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#6
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Re: LEDs Made Brighter and Cheaper

02/23/2012 6:52 AM

Ron,

That's precisely my strategy.

Solar PV cells generate 24vDC into storage batteries, then into dedicated circuits that suppply only, and all, lighting.

The 1000w panels and the 600a/h lead acid batteries are too big, but I'm happy that there is capacity to have lighting even if there is NO sun for a week or more.

This comment may sound strange to some, but I do live in "sunny Queensland", in OZ.

I'll add another system, and invert it to supply the washer and AC water pressure pump, clothes iron, and a few other minor items which are difficult to purchase in anything other than 230vAC.

Two systems will give service redundancy.

Stu.

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#7
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Re: LEDs Made Brighter and Cheaper

02/23/2012 7:25 AM

You read my mind ron. I've been thinking about this for over a month. Not only lighting, but for people that want to use solar arrays, a whole house DC system with small inverters only where needed.

There is the heat problem with LED's too, but I think they'll find a remedy for that.

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#23
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Re: LEDs Made Brighter and Cheaper

03/18/2012 1:26 AM

do you think that micro-inverters could be placed in the bulbs themselves? or maybe in they could be placed in the light sockets themselves that way no need to rewire at all.

The CFL Bulbs have transistors and capacitors to transform the electric for instant on feature eliminating the bulky transformers that the older FL bulbs needed.

Couldn't a transistor and capacitors be set up to do electrical inversion for LED arrayed bulbs?

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#10
In reply to #1

Re: LEDs Made Brighter and Cheaper

02/23/2012 9:18 AM

This just adds more cost in the front end in wiring and the centralized power supply at the panel or distributed power supplies or what ever other topology is used.

Nothing is free.

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#19
In reply to #1

Re: LEDs Made Brighter and Cheaper

02/26/2012 6:25 PM

Just remember that DC can introduce electrolysis issues, leading to corrosion and bad connections, particularly where humidity is high. You should not have too much of this DC wiring, and you should avoid drawing much current in the circuit.

AC doesn't have such a problem. Better to generate your DC at the point where it is used. In other words have a bunch of small DC supplies run from an AC source. I grant you not as efficient, but I prefer to avoid annoying maintenance.

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#5

Re: LEDs Made Brighter and Cheaper

02/23/2012 5:18 AM

I am still waiting for a LED replacement for my incandescent bulbs. I want 12/13 Watts minimum at $5. I can only find 6 Watts at around $7. Is anybody offering what I am looking for?

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#8

Re: LEDs Made Brighter and Cheaper

02/23/2012 8:42 AM

Welcome to world of electronic. Every six month product get smaller and better. This is our norm of manufacturing from last 30 years and will be for another 100 years. Only thing one needs to do size reduction and automation to improve product quality. I have predicted 5 years back LED is the technology for now and then will migrate to other new technology and in doing this we will improve product biggest problem of heat related degradation of LED. This will decrease power and cost further. Actual lighting bulb cost should not be more than US$1.00 and this will happen by 2030

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#15
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Re: LEDs Made Brighter and Cheaper

02/23/2012 6:45 PM

I am happy at $5, knowing that the LED lamp will outlive me. 50,000 hours 24 hrs per day is 6 years. If it lasts 20 years with average use, that's good enough.

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#9

Re: LEDs Made Brighter and Cheaper

02/23/2012 8:50 AM

The problem I have with LED's is the low light intensities available. My company has been researching the use of LED luminaires for use on roadways and in buildings. The vendors tell me, "We have a direct replacement for a 250W HPS lamp, and it only uses 50 watts of electricity." Sounds great, right? But when you pin them down and get them to furnish IES photometric files, you find out that that 50 watt LED is not only using less electricity, but it's only producing a fraction of the light of the HPS. Then they go into a snake oil routine about how the LED's white light produces more light than the footcandles would indicate. Yeah, right. How they get away with saying it's the "equivalent" of a more powerful light source, I don't know. We have found a few LED luminaire manufacturer's, mostly established lighting companies like Holophane and Philips, that are honest about their results. And a few LED light fixtures are even more efficient than their HPS counterparts, producing similar light levels. However, those lights that produce the same light level for less energy are few.

The primary benefit of LED that we have found is the lamp life. According to Sylvania, a typical HPS 250W lamp shoud have a life of around 24000 hours. An equivalent LED should (according to advertising) have a life of around 70000 - 100000 hours. So maintenance and relamping costs are greatly reduced.

Judging from past history, the LED's are getting more and more efficient. Maybe in another 10 years, they'll actually produce an LED light giving the energy efficiencies that some companies claim they have now. I think LED's have a place in future building, but with a few exceptions, most are not really ready for prime time, yet.

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#11
In reply to #9

Re: LEDs Made Brighter and Cheaper

02/23/2012 4:13 PM

A High Pressure Sodium lamp is a much more efficient visible light producer than an incandescent lamp. I suspect the comparisons you've been given are to an incandescent and not a HPS. Also the spectrum of the HPS is much broader than even the white phosphor based LED. They only appear to be white to our eyes. So a 50W white LED will look the same for us, but your plants will notice the difference.

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#13
In reply to #11

Re: LEDs Made Brighter and Cheaper

02/23/2012 4:28 PM

Sorry to disappoint, but we have been researching LED fixtures for use on various highway and tunnel applications for the last year. HPS is the standard for federal or state roadway lighting, precisely because it is (or has been) the most efficient light source available. This is exactly the market that the LED manufacturers of roadway luminaires have been shooting for. Their claims specifically state that they are the equivalent of HPS, even though the photometrics do not bear this out. As I said earlier, most of the well established companies are NOT making such wild claims, just the newer companies. Most people seem to prefer the color of the 4000 degree Kelvin LEDs to HPS, but the economics just aren't there to justify it in most cases. By comparison, most HPS lamps operate at 1900 to 2100 degrees Kelvin (per Sylvania), much redder.

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#14
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Re: LEDs Made Brighter and Cheaper

02/23/2012 5:18 PM

It appears you company is looking product which is available in cost effective to implement to roadway and in house.

LED and HPS are not comparable. You need to target correct LED bulb to achieve and currently no one makes its.

LED has advantage of putting in small form factor lot of LEDS and LED quality is improving as time passes.

Heat is still issue for LED along with LED assembly. I have not worked in LED area and for sure have not made any LED bulb but this is close to my heart and have presented paper on this topic in paste.

LED if correct thermal management will beat any HPS lighting system.

LED thermal management is still issue with respect to cost effectiveness of product

LED is still new technology and needs Fed incentive like solar and other green energy and oil industries help to make it available to every house hold

It will be more effective if we drop voltage from 110 to 24 Volt or lower

But I am predicting this technology will be in each of our home by 2030

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#12

Re: LEDs Made Brighter and Cheaper

02/23/2012 4:26 PM

I have a small nit to pick here in this write up. A diode is not made from semiconductors that have an excess or deficit of electrons. Ions have an excess or deficit of electrons. Turning a diode into an ion is how one releases the inherent smoke inside the diode. Once the inherent smoke of any electronic part is released they don't work any more. A diode is made by adding neutrally charged donor or acceptor impurities to a semiconductor crystal lattice.

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#21

Re: LEDs Made Brighter and Cheaper

03/12/2012 6:02 AM

Compact Fluorescent bulbs have some circuitry to help the bulbs start up instantly. so why can't some sort of micro-inverter circuitry be placed in the base of the LED bulbs to bring the current to DC, instead of rewiring your houses AC wiring to accommodate DC for the LED lights?

Not only place a micro-inverter to run them on DC but a small storage cell so if there is a black out the lights will operate if the switch is turned on (for a limited time of course)?

I am using the CFL bulbs, they are expensive and can have long life. But the biggest thing to these "green" CFL bulbs is that their manufacturing and disposal are not so green. these bulbs have mercury in them and if broken can be inhaled. In China where they are manufactured they are polluting there lands with the industrial waste from making these bulbs.

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#22

Re: LEDs Made Brighter and Cheaper

03/13/2012 8:06 PM

if some sort of micro-Inverter cannot be placed in the LED bulb the invention of a light socket with a micro-inverter and small storage cell for brown outs is feasible. then you could manufacture the bulbs in DC and just install the proper socket to operate the lights efficiently and effectively without all the expense of re-wiring the lighting system of homes.

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