Power Generation With Nanotubes

NubKnacker writes "Business World is carrying an article about how an Indian scientiest at IIT, Bangalore has come up with a new innovative method to produce power by blowing gases over carbon nanotubes. The underlying physics of the idea is quite simple yet no one had thought of it until today."

Very cool, related story in Nature

[tao_of_biology]

The journal Nature [nature.com] just ran a seperate news story a couple weeks ago about carban nanotubes' properties with regards to temperature. That story can be found here [nature.com].

From the Nature article:

Ortwin Hess from the University of Surrey, Guildford, UK and colleagues say that if you took the temperature at one end of a 10-micrometre nanotube, it would not necessarily have the same temperature as the other end, no matter how long it was left to reach a thermal equilibrium. Such a nanotube is about as long as a sheet of paper is thick.

Now, I'm definitely no physicist so please pardon my ignorance--maybe someone can help me out. Does this mean that the temperature differential created on the carbon nanotube wire that causes the current to flow won't ever reach equilibrium? Doesn't this seem too good to be true? Just keep blowing gas over the wire, and you'll have limitless energy.

Re:Very cool, related story in Nature

[ToshiroOC]

It costs energy to blow gas over the wire.

Gedanken experiment:
You have two tanks of air at equal pressure, and a nanotube setup like the one described in the article in the valve connecting the two tanks. You open the valve - and no air moves across the nanotube, since the tanks are at equal pressure. Now, you pump air from tank 1 to tank 2, and the nanotube will generate energy - but only an equal or lesser amount of energy than it took to pump the air across the tanks.

Re:Very cool, related story in Nature

[hawkbug]

Fortunately, that's why we are able to use the sun to heat one tank of gas (Aka green house) and then open the valve - so during the day, solar power heats the gas so we can use it to generate electricity.

Re:Very cool, related story in Nature

[Nos.]

Serious question here

Since windmills are so popular, couldn't we use them to inflate a balloon at the bottom of one tank and cause pressure to start the flow. Then release the balloon which would reverse the flow (and still generate current, from what I understand) then repeat?

I just know that in some areas of the world, wind is a more steady source of power than solar.

Re:Very cool, related story in Nature

[arete]

probably not.

Mechanical work (wind-power, hydroelectric, bicycle generator, regenerative braking) is already a low-entropy source... it's easy to capture it, and while it can't be lossless we have techniques that can generally come pretty close to the theoretical values for capturing it.

(which doesn't mean it can't be better, lighter, cheaper - but they're basically pretty good)

A pressure differential is somewhat worse - and a heat source (solar heating, gasoline, diesel, natural gas, coal, heating oil..

Re:Very cool, related story in Nature

[mdielmann]

And at night, when the tank cools down, you can generate energy again, from the air going in the opposite direction. This system generates energy in much the same way as a stirling engine does - moving heat to generate kinetic energy vs. moving air to generate electric energy.

I haven't read the article (I'm not that new here), but if there was an issue with the direction of flow, a simple system with 2 bi-directional valves and a little extra pipe could guarantee the gas flowed in a given direction that section of pipe, regardless of which tank was the source and which was the destination.

Re:Very cool, related story in Nature

[pipingguy]

The net yield from solar energy is not that great and there are huge infrastucture costs involved. As long as oil, coal and nukes work, there's no incentive to change. Chicken Little doomsaying by the radical environmentalists only hurts their position, but hey, everyone needs a job.

Re:Very cool, related story in Nature

[hawkbug]

I disagree 100% - mainly because efficiency of these projects increase all the time. Solar isn't that expensive when you project the costs out over 30 years for example for the average home. Say every home had solar panels on the roof, and the average cost was $20k per home, which it is at present time. The average solar set up lasts between 20 and 30 years if properly maintained. How is that not cheaper than paying a utility bill? After 5 years, the gear would be paid off, netting an average of 15 - 25

Re:Very cool, related story in Nature

[pipingguy]

Sure, but what is the cost of getting that technology into place? Current solar panels are expensive and easily damaged and can only work effectively in certain areas. I agree that the efficiency is going up but it's not at a pace that it can compete with current power generation technologies within the next 30 years.

The US uses coal as the main generator of electricity and that can be cleaned-up by oxygenation. Nukes are also a good option, but since privatization of the power industries tends to create

Re:Very cool, related story in Nature

[hawkbug]

Well, most people who install them do so themselves - you just place mountaing brackets on your roof and screw the panels on. The only tricky part is the electrical wiring back into the grid, which you could pay somebody to do because it needs to be inspected anyhow. As far as the panels being damaged, I don't think that's a problem anymore - they build them very well from what I understand, especially if their life expentency is around 25 years. They would work great in states like Nevada, Colorado, Cal

Re:Very cool, related story in Nature

[pipingguy]

Tidal power interests me (since it tends to involve pipes :). There are some pilot plants in Nova Scotia [nspower.ca]/New Brunswick. Full implementation would be a massive project, but it's doable.

If done properly, nucular is safe but you wouldn't want Homer Simpson as an operator. I don't see where cancer comes into the matter.

Probably the best overall solution for power generation is hydroelectricity as is used in Quebec. However, the manpower and dedication needed to create this (not to mention the required geogr

Re:Very cool, related story in Nature

[thebigmacd]

You know what happened to the Nova Scotia plant the other week...a sperm whale ended up upriver from the plant and they shut it down indefinitely until they could coax the whale back through the way it came.

Not very reliable. Of course if they just ignored the whale the plant wouldn't be down.

Re:Very cool, related story in Nature

[bhima]

I remember reading a study which claimed that by the time a solar panel was installed, more energy had been consumed that it ever would produce...but it's been a while.

Re:Very cool, related story in Nature

[man_ls]

Maybe these could be used to improve the efficiency of power plants that exploit the gravitational potential energy of the earth (i.e.: hydroelectric power plants)

Kind of like an afterburner on the power plant...these could be placed inline after the turbines and generate an extra kick. Plus, that energy is basically "free" since the stored energy comes from its position in the earth, presumably energy that was placed there through natural, renewable processes (as opposed, say, to pumping it up the side of

Re:Very cool, related story in Nature

[Anonymous Coward]

Kind of like an afterburner on the power plant...these could be placed inline after the turbines and generate an extra kick.

Except in order to generate power the wires have to put a drag on the gas flow. That drag puts drag on the turbines and probably costs more than it produces.

Re:Very cool, related story in Nature

[Josh Booth]

It will, which is why you must keep the wire at an angle to make one side cooler than the other, or some such business. Eventually, the tube will get as warm as the air blowing on it otherwise, yielding no electricity.

Re:Very cool, related story in Nature

[k98sven]

Does this mean that the temperature differential created on the carbon nanotube wire that causes the current to flow won't ever reach equilibrium? Doesn't this seem too good to be true? Just keep blowing gas over the wire, and you'll have limitless energy.

No.. see, they're referring to something different here. That without any gas flow or anything, there can be a temperature difference on a nanotube which doesn't reach equillibrium. Now that is something which is remarkable, because it seems to violate

Cost prohibitive for non-sensing applications

[ToshiroOC]

Unfortunately, nanotubes are still so expensive, velocity sensors are probably all these would be good for - larger power generating variants would be cost prohibitive. I also wonder how robust any velocity sensor made with nanotubes could be; sure, you could probably put one in a steam pipe or a LNG line and get reasonable data (in fact, in any nanotube-friendly chemical you could probably get good data from this sensor), but if you wanted to put one on the outside of a car or an airplane for velocity measurements, I can see nanotubes being easily damaged; either pulled from their moorings/leads in the device or simply snapped - nanotubes may be strong, but that's not going to help if you have a 500mph tiny sharp projectile impact just a few nanotubes. Also, in 'dirty' environments such as those outside of a car or a plane, you would probably start getting buildup of different pollutions at a reasonable rate, causing a need for either a) constant recalibration or b) sensor replacement.

Re:Cost prohibitive for non-sensing applications

[Delf]

RTFA, it's not just nanotubes that demonstate the effect:

Ajay Sood, professor of physics at the Indian Institute of Science in Bangalore, and his student Shankar Ghosh blew a gas over a piece of wire and watched it generate electric current. Two years ago he had blown water over ultra-tiny wires - carbon nanotubes - and watched them generate a current too. Carbon nanotubes are bits of exotica for the layperson; you expect them to behave in ways that you had not known before. Some of the wires in the second

Re:Cost prohibitive for non-sensing applications

[ToshiroOC]

Show me someone using very thin wires for velocity sensors already and I'll accede that I didn't know about that, but I fail to see where I missed anything in the article. I never said you couldn't do it with non-nanotube materials, now did I?

Re:Cost prohibitive for non-sensing applications

[Delf]

You seem to have applied the same leet reading comprehension skills to my comment as you did to the article.

As I pointed out in the quotation from the article in question, the effect has been demonstrated by the same researcher using other materials than nanotubes -- materials that are already common, readily available and much more robust than nanotubes. Given that fact, amply explained in the article as I quoted originally, I see far less reason than you to be pessimistic about this effect seeing commerc

SCO will be saved!

[SpaceLifeForm]

Yep, all of the smoke they have been blowing can finally be put to good use.

Efficiency?

[Anonymous Coward]

Does anyone know how efficient this system is? Depending it could become even more widespread than the article suggests.

That was amazing.

[Randolpho]

It is exactly what they've mentioned: so simple nobody ever thought of it.

Seriously, the potential applications to this just for minute gas-flow sensing are astounding; if this were ever exploited for consumer energy..... I think the guy deserves a Nobel prize for it.

Re:That was amazing.

[BigJimSlade]

It is exactly what they've mentioned: so simple nobody ever thought of it.

Maybe you didn't think of it...

I did.

But, you know, I've been like... busy, and stuff.

IISc and not IIT

[florist]

It is Indian Institute of Science Bangalore [ernet.in] and not IIT [google.com]

Re:IISc and not IIT

[NubKnacker]

Mistake on my part.

How was this "unknown"?

[RealErmine]

According to this [xyroth-enterprises.co.uk] the Seebeck Effect (current flow from temperature difference) is just the reverse of the Peltier Effect (temperature difference from current flow). It's been known that the semiconductor material of a Thermoelectric cooler (or Peltier cooler) works in reverse, generating current from a temperature difference between sides. The story seems to imply that this is a new discovery both for nanotubes and other semiconductors and it's been known that nanotubes can act as semiconductors. It does not exlplain how doing this with a wire and a moving gas is new.

Re:How was this "unknown"?

[Randolpho]

It's not "unknown", it's just "undone" before. It's been known that you could get a current by creating a temperature differentiation on both wires and nanotubes. It's just that nobody had ever tried to create a temperature difference through the Bernoulli Principle. Nobody did it before this guy, the guy deserves credit for it for thinking of it first, even though it seems so damn obvious to us now.

Think of it this way:

We knew about peanutbutter. We knew about chocolate. We knew they both taste good. But we didn't know they tasted so damn good together until they came out with Reese's Peanutbutter Cups. Thank you Mr. Reese, whomever you are. ;)

Re:How was this "unknown"?

[RealErmine]

It's been known that you could get a current by creating a temperature differentiation on both wires and nanotubes. It's just that nobody had ever tried to create a temperature difference through the Bernoulli Principle.

Well then I'd like to submit, for the approval of the science community, my method of power generation by ice cube and Zippo lighter.

Cows?

[jo42]

> blowing gases

Methane perhaps? Cow farts??

It's IISc. Not IIT

[Valluvan]

See New Scientist archive [ernet.in].

This has been done...

[ElectricRook]

Not to rain on the parade of some good investigation of a new material, but Nicoli Tesla did something similar with wires suspended in a flowing river.

How is this dis-similar from a hot wire anemometer?

Caption

[DavidNWelton]

High school physics meets nanotech: Ajay Sood (R) with student Shankar Ghosh passed gases over carbon nanotube wires to generate measurable electric current

Well... that's a lab I wouldn't want to work in.

Lower your shields

[kdark1701]

Resistance is futile