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Solar Cells Crystallized Out of Molten Silicon
Hot Toddy sends in a link to a story up on Digital World Tokyo about a more efficient process for manufacturing solar cells. It involves dropping molten silicon from a height of 14 m; surface tension causes tiny spheres 1 mm in diameter to form; the silicon crystallizes in the 1.5 seconds of free-fall. The spheres can be mounted on surfaces of any shape. They capture light from many directions, increasing their solar efficiency. Kyosemi is the company behind the Sphelar technology. Some of the pages on this site date to 2003 and the status of most listed Sphelar products is either "under development" or "engineering sample is available."
For example, the statement about solar panels not having to be flat already applies: there are flexible, stickable (see the UniSolar laminate for example) ones now, with Fresnel lenses etc.
In fact, for many uses, solar is easily laid on an existing flat surface such as a roof. Flat is very often convenient.
The issue about capturing light from any angle is only valid if the individual cells/balls and their connectors (and any surrounding obstacles such as walls and trees) don't get in the way. Multi-layer cells and mechanical trackers and even mirrors mitigate these problems in existing systems: http://www.earth.org.uk/note-on-solar-PV-for-diffuse-light.html
Anyway, interesting, and it would be good to test some in places like the tops of walls, roof ridges, pathways, etc.
Rgds
Damon
http://m.earth.org.uk/
Uh, this looks like the same thing that came out from Spheral Solar Power, that was bought (and later divested) by Automation Tooling Systems:
http://environment.newscientist.com/article/dn3380
Try to hack my 31337 firewall!
Neat! This is the same method that was used to make cannonballs during the US Civil War.
I can't find any references to cannon ball manufacture on Wikipedia, but my high school had a cannon forming tower (it was originally a civil war arsenal).
Outside of that, the more techniques the merrier! I'm somewhat curious how they create a PN junction out of a homogenous liquid of silicon, but I suppose that can be done afterwards. I'd also be a bit curious if it's single crystalline. I very much doubt it, as there is no seed crystal to nucleate on, so there should be a lot of independent surface nucleation sites (IAAMS).
So nobody's been payint attention to Innovalight in the news lately?
They have the cheaper and more efficient technology:
http://www.news.com/Pour-yourself-a-silicon-solar-panel/2100-11392_3-6213132.html?tag=nefd.top
www1.eere.energy.gov/solar/solar_america/pdfs/41741.pdf
Multiple Exciton Generation is where it's at. Only nanoparticle quantum dots can achieve that, and it's the means to get the highest solar efficiency, because it 's about generating multiple electrons of current for each photon absorbed by your photovoltaic material.
So let me be the first to say it -- ours is bigger than yours!
Do not mock my vision of impractical footwear
Sounds like one of those accidental discoveries...
"Ah crap, I just knocked over the vat of molten silicon we had sitting on the roof ledge!! My boss is gonna be super mad at.... oh hey, look at all these little balls! Weeee, silicon balls!"
Yeah, but pointing down.
Bert
You know, a crystal structure sure has a lot of surface area compared to its weight, maybe, just maybe -- no! definitely, it's an idea, I feel it coming, it's, it's -- a-hem:
I HAVE A DREAM.
I have a dream,
That one day,
Crystallized solar cells will be so light
And so cheap
That you could spray them on a helium balloon.
And that you will.
On half of the balloon.
Only the balloon is parabolic.
And the inside is coated -- half of it,
Yes, forming the shape of a dish,
With something that reflects radiowaves.
And I have a dream
That one day there will be a wireless networking chip so light
And so cheap
That you can buy it in packs of ten.
And you will.
And you will tape it outside that parabolic balloon
Opposite and facing the side
With the insides all radioreflective, facing out like a radar dish.
And the outsides -- the top of the balloon,
And of the part all coated to be radioreflective
Will be crystallized solar cells.
And the power output from the crystallized solar cells
You will run around to power the wireless chip across from the painted side,
Which you will connect with another wireless chip at the base of the balloon,
Facing down.
Into your house.
Repeating the signal.
And then you will fill the balloon with helium and set it free.
Free to float with the wind, tethered to the top of your house.
Four of them, one at each corner of your house.
Turning randomly with the wind.
Like radar dishes.
Only, higher -- much, much, higher.
Like a radio tower.
Because you will tether them with very long string.
And slashdot will report it.
And hundreds of other geeks in your metro area will do the same.
And you will all get good wifi,
Jumping from hotspot to hotspot
As the balloons turn.
And the story will be reposted.
But it will not be a dupe.
Because I have a dream, that the dupe will be with a wireless chip
That does mesh networking.
Yes, one day, in the not so distant future,
Rich little slashdotters and poor little slashdotters
Will fly solar-powered helium balloons
With radio-reflective coated insides,
And mesh networking wireless chips,
And you will forward all the appropriate ports,
And be network neutral,
And it will cost you $7.50
Which will amortize over
Forever.
Disclaimer: Evolution comes with NO WARRANTY, except for the IMPLIED WARRANTY of FITNESS FOR A PARTICULAR PURPOSE.
Missing from the story are important and obvious details.
1. Electrical output efficiency compared to a correctly aimed flat solar panel.
2. How are tiny silicon balls connected to produce electricity?
Any other questions, please chip in.
Thanks, Jim
Hot liquid metal inside an aircraft - what fun! Look up "liquid metal embrittlement" to see why this would have to be done very carefully and why you currently cannot take mercury on an aircraft. In short the liquid metal gets into any small flaws, dissolves it into a sharp crack quickly, and then after a short time the crack gets long enough that it goes at the speed of sound in the material - more than 4miles/second (6.6km/s) in steel.
... hopefully it'll have legs, too.
"Win treats sysadmins better than users. Mac treats users better than sysadmins. Linux treats everyone like sysadmins."
Yes. Clearly I'm new here...
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Someone misled you. Shot (for shotguns) is made in freefall using a tower. And it basically does work the way you're thinking: it doesn't necessarily solidify all the way, but the outside does, and that's enough for it to retain its shape when it hits the water at the bottom of the tower.
Cannonballs were generally made out of cast iron. If you look at an authentic one that's in good shape, you can usually see the mold lines and sprue marks where it was poured. They were usually poured into sand molds that were then knocked away after they cooled.
Some very old cannon balls (prior to the 18th century at least) were cast bronze or cut stone rather than iron, but most people switched to iron as soon as they were able to because it's a harder, cheaper material than bronze, and easier to work with and more effective than stone. (Bronze remained as a material for the cannons themselves well into the 19th century, though, since it has greater tensile strength than cast iron and is less likely to shatter.)
Also, if you think about pouring large quantities of viscous liquid, you'd realize that "dropping" a cannonball wouldn't work; rather than forming a sphere, you'd probably form a teardrop or ellipsoidal shape* due to the air resistance. Forming spheres via freefall cooling is only practical (in normal Earth gravity) for rather small parts, where the surface area to mass ratio is low.
* I'm told that if you look at the shot produced in a shot tower closely enough, all of it is really ellipsoidal rather than truly spherical, but it's such a small difference that it's normally ignored.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
Peak oil is an environmental problem, not an economic problem. There are lots of fuel alternatives, they are just expensive or environmentally damaging. As oil prices rise, alternative methods of energy storage become viable. As alternative energy sources become profitable, the price of oil drops. The result is that no matter how hard you try, you can't force oil prices up rapidly over a long period of time. The worst that will happen will be a steady long term climb as oil is phased out and new energy sources are phased in.
The real danger in peak oil is the environmental impact. As oil becomes more expensive, alternative methods of fueling vehicles will be needed. Now, there are lots of viable alternatives to get buy one little to no oil. The problem is that all the alternatives require spending energy... energy that will likely come from the grid. You could switch to a hydrogen fueled car or plug in hybrids for instance in a few years. The problem is that making hydrogen (or any alternative fuel) or to recharge off the grid is going to demand you spend energy from the grid. This is good in that your automotive industry becomes as clean as your gird... so if you have a clean grid, you have a clean automotive industry. The downside is that as you pull more power from the grid, energy prices go up. The only way to keep them down and keep from killing the grid is to put more power online. Coal is the cheapest and most efficient way to dump more power into the grid, but coal has the downside of being less than friendly to the environment or good for CO2 emissions.
My point is that the world will move on smoothly from peak oil (should it exist). The market will happily even out the price and the transition will be smooth. The real danger is an environmental danger as we scramble to get energy from alternative sources.
At the moment, we pretty much drill a hole in the ground and start sucking. The energy put in is tiny relative to the energy we get out. As we have to put more energy in to find our energy we have less energy to expend elsewhere. Even nuclear energy has a lower energy return than oil does. When the ratio of energy input to energy output falls to 1:1, the entire economy is employed finding and exploiting new sources of energy. So as we move from oil, the energy sector takes up larger and larger proportions of our spending and investment.
While I don't doubt that market forces will make us move to different fuels, those same market forces may also require us to abandon our cars and skyscrapers. There is nothing magical about the market, it's simply individuals making choices. The reason I asked "is there going to be enough time" is that alternative infrastructures take time, perhaps 10-20 years to build.
Deleted
Nice idea, I'd also check out concentrating solar power though. To me this seems to be a simple, conventional engineering task. Future information here: CSP on The Oil Drum