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New competitor may enter the lighting fray thanks to new research

The future of LED lighting is looking bright.  Endorsed by a $20M USD U.S. Department of Energy "L Prize", commercial powers and startups alike are eying LED lighting as a replacement for the decrepit incandescent light bulb technology, which is only 10 percent efficient and has remained almost unchanged for over half a century.  Recent breakthroughs, which may allow LEDs of all kinds to be processed on silicon wafers, may help to bring down costs.

One player that remained largely unconsidered in the LED v. fluorescent/incandescent battle was LED's organic brethren: OLEDs.  OLEDs have many advantages over LEDs -- the ability to flex, improved color, and the potential to be manufactured by cheaper organic ink printing processes.  However, they also have a couple key disadvantages.  One, lifetime, has been steadily chipped away, and with the first generation of OLED TV displays, the problem has become almost a nonissue.  However, one key obstacle to OLED lighting remained -- brightness.

Typically with OLEDs, only 20 percent of the light generated by the device is emitted.  This makes there brightness inferior to LEDs, making them a poor choice for lighting.  However, in a significant breakthrough, researchers at the University of Michigan and Princeton University have developed an OLED/microlense combination material that boosts illumination by over 60 percent, bringing it into the realm of respectability.

The research was led by Stephen Forrest, a professor of electrical engineering and physics at Michigan, and Yuri Sun, from Princeton University.  The pair observed that in OLEDs light is generated by applying electricity to a thin organic layer, analogous to the semiconductor in an LED.  However in OLEDs the material character internally reflects the light, forcing it to run parallel, instead of perpendicularly out of the bulb.

To get the light to come out, researchers first use an organic grid meshed into the material.  The light is guided by this grid to 5 micrometer domed microlenses, which focus it and project it out as rays. 

The results are respectable.  The researchers reported that the device produced 70 lumens per watt, compared with 15 lumens per watt for incandescent lighting, and 90 lumens per watt for fluorescent lighting.  While it might seem that fluorescent beats the new OLEDs, fluorescent has other problems -- harsh light, less longevity, and the use of environment-damaging substances like mercury.

The team plans to next scale the technology to more efficient OLED designs.  They are confident the process can be affordably adopted for mass commercial production.

The DOE is curious about the new technology, seeing as a way to possibly more affordably reach its LED adoption goals.  If LEDs are widely adopted, according to the DOE, U.S. energy consumption for lighting could be cut to a third of current levels, resulting in a 10 percent total reduction in power use and a  258 million metric ton reduction in carbon emissions.

As both LED and OLED technologies are rapidly advancing in terms of production and efficiencies, it remains to be seen which will ultimately prove themselves the eventual victor via performance and cost.  However, in Professor Forrest's eyes, the future of OLEDs has never looked better.  He is confident that OLEDs will thrive, and that his team's breakthrough will aid in that success.  He states optimistically, "Luckily, OLEDs are the light that just keeps giving.  There is so much to be done and so much that's been done, but this is nonetheless a quite exciting advancement."

The team's research will be reported in the August issue of the journal Nature Photonics.

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Slowly stepping in the right direction
By wordsworm on 7/24/2008 9:51:49 AM , Rating: 2
quote:
If LEDs are widely adopted, according to the DOE, U.S. energy consumption for lighting could be cut to a third of current levels, resulting in a 10 percent total reduction in power use and a 258 million metric ton reduction in carbon emissions.


I think they're missing the fact that the heat that conventional lighting has to be compensated for by airconditioning on warm days. In the winter, of course, that extra electricity spent gets used since you need the heat anyways. So, the amount of reductions are likely under-estimated.

The real trick to this is for Canada/USA, et al, to ban incandescent lighting altogether, as has Australia, Cuba, Brazil, etc.




RE: Slowly stepping in the right direction
By masher2 (blog) on 7/24/2008 10:16:42 AM , Rating: 1
> "So, the amount of reductions are likely under-estimated."

It essentially balances out, except in very hot climates. In cold weather, incandescent lights provide free heat with the "wasted" electricity not generating light, meaning the cost is actually drastically overestimated. In warm weather, it's underestimated.


By AnnihilatorX on 7/24/2008 11:04:33 AM , Rating: 2
I doubt there is significant over or under estimation if any.

A 100W incadscent lamp is the power output of 1/15-1/30 of a conventional heater. Human is too insensitive to such a small effect on temperature and he/she would have turned on the aircon/heater regardless whether be that an incadescent lamp or a super energy efficient lamp is in the room since the room temperature.

The over/under estimation occurs when the airconditioner or heater has automatic temperature stablising control.


RE: Slowly stepping in the right direction
By wordsworm on 7/24/2008 12:13:40 PM , Rating: 1
How do you mean it balances out? Nothing balances out. In the winter it balances since it gives off some heat which assists the heating elements throughout the house, but in the summer the AC has to fight the lighting. That's not balancing out. It means you waste energy 2x in the summer, but you don't waste energy in the winter. Using your words, it balances out in the winter. However, in the summer it adds to your energy costs. So, unless you live somewhere where it's always cold, there is no balancing of energy.

Look, truth is that I like incandescent better. The warm glow sure beats the LEDs or OLEDs that I've seen. However, I've gone over to fluorescent and LED simply for economic reasons.


RE: Slowly stepping in the right direction
By adiposity on 7/24/2008 12:41:37 PM , Rating: 2
I think what he means is, if you DON'T have the incandescent lighting, you have to cool in the summer, and heat in the winter. If you DO have it, you have to cool 2X in the summer, but not heat in the winter. So it "balances" in that the same amount of energy is used either way.

Obviously it's an oversimplification, but try this:

Incandescent Lighting:
Winter: 0 units of energy used for heating
Summer: 2 units of energy used for cooling
------------------------------
= 2 total units

LED Lighting:
Winter: 1 unit of energy used for heating
Summer: 1 units of energy used for cooling
------------------------------
= 2 total units

Since 2 = 2, whether you use a light that heats or not, it balances out to about the same amount of energy. Obviously, if you have shorter winters, or warmer winters, it doesn't balance. Basically, given the right climate, any additional energy you waste to cool in the summer (due to lighting) should be offest by energy you save in the winter (due to lighting).

Dan


RE: Slowly stepping in the right direction
By wordsworm on 7/24/2008 4:29:08 PM , Rating: 4
I know what he means. The problem is that the balance only works in the winter. So, let's try your math again.

INCANDESCENT (100 watts of heat generated by incandescent lights in the house)
winter
heater 900 watts
lights 100 watts of heat
----------------
= 1,000 watts

summer
lights 100 watts of heat
AC 1,100 watts of cooling (to compensate for the lights)
-------
= 1,200 watts

PERFECT LIGHTS (hypothetical no heat generating lights)
winter
heater 1,000 watts
lights 0 watts
-----
= 1,000 watts

summer
AC 1,000 watts
lights 0 watts
-----
= 1,000 watts

That's the correct way to simplify things. There is no 'balance' except in winter. Every summer you'll be wasting electricity in order to cool off the amount of heat energy generated by the lights. Of course, this is an oversimplification. I doubt heartily that it takes 100 watts of electricity to cool off 100 watts of heat. Nothing ever works that well. Surely it would take a lot more energy than that. However, as I said before, and in terms that are simpler, there's no balancing of energy trade off throughout a given year. Only in winter will the heat from the lights actually reduce the energy required by a heating device. This is, of course, based on 100 watts of lighting energy. Surely most people who use incandescent lights have more than 100 watts of lighting in their house.


RE: Slowly stepping in the right direction
By ZmaxDP on 7/24/2008 7:08:49 PM , Rating: 4
Actually, air conditioning isn't a closed system either if you're using a typical compressor. So, it can actually take less energy in the summer to offset the heat of the lights than what the lights emit. So, if your lights put out 100W of energy converted to heat, your AC compressor can move that heat outside and replace it with cool air at a cost of maybe 30 to 40 Watts.

Your argument still stands though as it would take more than 4 times as much energy to generate the same amount of heat from incandescent lighting as it would to generate that heat with a heat pump. So, while the AC is more efficient in removing heat from the house than the light is at generating it, the heat pump is also more efficient at heating the house in the winter.

Of course, if you're using natural gas in the winter then all bets are off...


RE: Slowly stepping in the right direction
By fic2 on 7/24/2008 7:21:44 PM , Rating: 3
There is also the fact that there is a lot of lighting in rooms that are always air conditioned - server rooms (hopefully with occupancy sensors), chillers in stores for food/wine/beer, etc. These systems are always fighting the heat given off by the lighting system.


By DragonMaster0 on 7/24/2008 7:57:48 PM , Rating: 2
But server rooms use HID lamps, much more efficient than CCFLs.


By adiposity on 7/25/2008 4:30:28 PM , Rating: 3
This is correct. However, it "balances" in the sense that the only cost incurred is that of the power of running the lights. The amount of energy used to run the heater balances in a perfect efficiency cooling situation.


RE: Slowly stepping in the right direction
By JonnyDough on 7/24/08, Rating: 0
RE: Slowly stepping in the right direction
By wordsworm on 7/25/2008 8:14:20 AM , Rating: 2
That light gets emitted in two basic waveforms: infrared and the spectrum that our eyes perceive. The purpose of a light should be to light up a room, not heat and light up a room. In the winter, there's no wasted energy, so afaik, if you're in the Antarctic where it's perpetually cold, you're just as efficient using one or the other in terms of electricity being spent. In the summer, the electricity is wasted two fold. That's my beef with them. Of course you wouldn't use lights to heat up a room. That's a consequence of using lights - greater for some forms than others. If I'm wrong on any count, maybe there's an inbetween spectrum where barely visible and barely warm burns up a lot of electricity that I don't know about.


RE: Slowly stepping in the right direction
By JonnyDough on 7/26/2008 2:45:28 PM , Rating: 1
Do some research on heating elements and coils. Apparently you're confused again there Mr. English teacher.


By wordsworm on 7/27/2008 12:57:57 AM , Rating: 2
No need to call me "Mr." My students call me by my first name followed by 'teacher' if they use my name at all. Usually it's just 'teacher.' Also, I'll be retiring for about 6 months in about 2 months.

In any case, most of the physics is beyond a simple glance for me. I tried to find a paper that would show me exactly the thermal differences between a 100 watt light bulb and a 10 watt LED with a 90 watt coil heater, and this is what I've come up with.

An incandescent light bulb is essentially a coil heater which heats up to several thousands of degrees Celsius, causing the filament to emit white light. The production of light is about 5% of the electricity, and the production of infrared, or heat, works out to about 95%. In any case, it's your turn to do a little reading. So, in summation, your 100 watt light bulb is 95% coil heater, and 5% light energy.


RE: Slowly stepping in the right direction
By Generic Guy on 7/24/2008 10:18:55 AM , Rating: 2
quote:
The real trick to this is for Canada/USA, et al, to ban incandescent lighting altogether...


Congress did effectively ban incandescent bulbs with last year's energy bill. More like, they set efficiency standards which regular filament bulbs can't meet. Of course the cutoff date is in 2012 to hopefully provide time for substitutes to be found.


By StevoLincolnite on 7/24/2008 1:25:07 PM , Rating: 2
The Australian Government are doing a slow phasing out of the "Traditional" Light bulb.

Plus Electric Hot Water Systems will be banned from being installed in South Australia, and any new houses bought after the end of this month, have to have an Alternative Hot Water System that is not electric.


By Oregonian2 on 7/24/2008 7:28:01 PM , Rating: 2
Sure hope the light bulb in our oven doesn't burn out.