Harvard Grid Computing Project Discovers 20k Organic Photovoltaic Molecules 125
Lucas123 writes "In June, Harvard's Clean Energy Project plans to release to solar power developers a list of the top 20,000 organic compounds, any one of which could be used to make cheap, printable photovoltaic cells (PVCs). The CEP uses the computing resources of IBM's World Community Grid for the computational chemistry to find the best molecules for organic photovoltaics culled the list from about 7 million. About 6,000 computers are part of the project at any one time. If successful, the crowdsourcing-style project, which has been crunching data for the past two-plus years, could lead to PVCs that cost about as much as paint to cover a one-meter square wall."
The big thing here is that they've discovered a lot of organic molecules that have the potential for 10% or better conversion; roughly equivalent to the current best PV material, and twice as efficient as other available organic PV materials.
Misleading statement in TFA (Score:5, Informative)
The current best PV materials have 20% or better conversion rate
Even the garden variety stuffs from China gets you about or above 15% conversion rate
I reckon the organic compounds are better, in the sense that they do not pollute the environment as much, but to that they are "equivalent" to the "best PV material" in terms of conversion rate, tastes a little bit funny to me
Re:Roughly equivalent my ass. (Score:5, Informative)
Try half. High efficiency silicon cells are up to 20%.
The best are now sitting at 44% (http://en.wikipedia.org/wiki/File:PVeff%28rev130307%29.jpg). That doesn't mean cheaper solar cells don't have lots of potential, but it does mean the editors here screwed up again. There are a few other errors in TFS as well, but this one really got me:
could lead to PVCs that cost about as much as paint to cover a one-meter square wall."
Huh? So does this mean a PV coating will will have the same cost per area as paint. Personal expertise tells me no. Does it mean a postage stamp of PV coating will coast as much as a square meter of paint? That's actually more realistic for the midterm future, but the language in TFS shows such a basic lack of understanding of both numbers and units that it's impossible to tell what the editor or submitter really meant to say.
Re:Roughly equivalent my ass. (Score:5, Informative)
Those 44% cells use an optical concentrator, aka magnifying glass, and require a substantial cooling system (concentrating the suns energy 418x creates a lot of heat)
They're also not commercially available, although neither are any cells using one of these 20,000 different molecules.
Re:Organic compounds (Score:5, Informative)
You first need to get your engine block to a temperature far beyond what it's designed to handle.
As I understood the point, they mixed this stuff with oil and then sprayed that mixture over the engine block. The hot engine ignited the oil and the burning oil reached the required temperature, presumably.
Re:Organic compounds (Score:5, Informative)
but I would think 500C is a bit unusual for an engine to operate at. That's roughly 900F, well above the melting point of, say, lead, and getting close to that of aluminum or magnesium.
If you pop open the hood and look along the sides of the engines, you'll notice that even though your block is aluminum, your exhaust manifold is not. The operating temperature of that will vary from 500 to 1000F for a V6 or V8. It will be higher if it is a rotary engine, or turbo-charged. A turbo-charger works by taking the pressure of the exhaust and using that to drive a turbine that compresses air and feeds it into the intake -- as a result, the exhaust will be at a much higher pressure, typically 9-12 PSI, and that results in the excess heat not dissipating as quickly. 1000F is easily attainable in a turbo-charged engine, like those typically found on the higher-end vehicles this refrigerant was/is installed in.
So by the time your engine block has reached 500C, you should already have run a good ways away.
As indicated earlier, the engine block is not the only source of heat under the hood, nor is it the hottest location. Also, the ignition temperature of gasoline can be much lower than 280C -- it can be as low as 232C (495F) [hypertextbook.com].
tetraflouropropene sounds like a hard chemical to aerosolize, which is also a condition needed for it to release HF.
It is in a closed loop refrigeration system. The typical pressures for the "high" side of a typical system is 200-350 PSI. Needless to say, a leak in the system would result in already-heated liquid that is designed to vaporize at 15-25 PSI being released into the atmosphere (at zero PSI)... which makes converting it to a gaseous state a simple matter of poking a hole somewhere in either loop; Though it would be somewhat more disasterous on the "high" side of the compressor.
So to recap:
Your understanding of physics is based on incorrect assumptions, and is incomplete as well.
Can't be much more dangerous than gasoline, which can kill you under far less unusual circumstances.
Yes, if you drink it I suppose. But many people have been doused in gasoline and unless they are lit on fire, find that it simply stinks and itches. And in many cases, people have survived being burned by gasoline spills that have caught fire. The same can not be said of anyone exposed to hydrofluoric acid. The CDC [cdc.gov] has a few things to say about it... namely that it can be used as a chemical weapon and is exceptionally toxic and fatal even in small amounts. Gasoline on the other hand...
Re:Roughly equivalent my ass. (Score:4, Informative)
We haven't used optical concentrators for 40% cells in quite a while. Now we use focused-bandgap absorption and silicon nano-structures to act as waveguides, no concentrator needed.
Re:Misleading statement in TFA (Score:4, Informative)