MIT's Millimeter Turbine to be Ready This Year

Iddo Genuth writes "After a decade of work, the first millimeter size turbine engine developed by researchers at MIT should become operational by the end of this summer. The new turbine engine will allow the creation of smaller and more powerful batteries than anything currently in existence. It might also serve as the basis for tiny powerful motors with applications ranging from micro UAVs to children's toys. In the more distant future huge arrays of hydrogen fueled millimeter turbine engines could even be the basis for clean, quiet and cost effective power plants."

Comments

Clean Power Plants?

[Whiney Mac Fanboy]

In the more distant future huge arrays of hydrogen fueled millimeter turbine engines could even be the basis for clean, quiet and cost effective power plants."

WTF? Where's the hydrogen coming from? May as well say In the more distant future huge arrays of kitten engines could even be the basis for clean, quiet and cost effective power plants."

Well, it could be!

Re:Clean Power Plants?

[Max Littlemore]

The hydrogen comes from the kittens, doofus!

Re:Clean Power Plants?

[dbIII]

WTF? Where's the hydrogen coming from?

From clean nuclear plants that require no mining, enrichment, hazardous waste disposal, have no concrete and so thus have no carbon dioxide impact and work far better than the tweaked 1950s dinosuars which are the only tested designs you could get built over the course of the next few years.

Methane from kittens would be almost as difficult to organise.

The proposal to "kickstart" the hydrogen economy consists of bizzare stuff like getting the hydrogen from methane - bizzare because methane is easier to ship, store and use and could come from biological sources (not just kittens) or from coalbeds.

These turbines sound fantastic in very small situations and it appears a journo is missing the point by wondering what big arrays would do and setting up for dissappointment.

Re:Clean Power Plants?

[brianosaurus]

Let's see... "Huge arrays of kittens" make a "QUIET [...] power plant". Yeah, right!

I don't even want to think about the litter box.

Re:Clean Power Plants?

[kfg]

WTF? Where's the hydrogen coming from?

Mr. Fusion!

KFG

Re:Clean Power Plants?

[mpe]

The proposal to "kickstart" the hydrogen economy consists of bizzare stuff like getting the hydrogen from methane - bizzare because methane is easier to ship, store and use and could come from biological sources (not just kittens) or from coalbeds.

There is also a perfectly good methane distribution system in many parts of the world. Which even supplys the fuel direct to buildings. The only thing apparently lacking is bottled methane for easy use in vehicles. Though no doubt many existing fuel stations could be fairly easily outfitted to bottle methane.
Whereas hydrogen requires massive changes of infrastructure and dealing with a fuel with some very inconvenient physical properties in the environment we'd actually want to use it.

Re:Clean Power Plants?

[TropicalCoder]

Even a thousand whispers can get pretty loud

I beg to differ. Wikipedia lists the sound pressure level of a whisper at 20 dBs. To calculate the sound of a thousand people whispering, we need to do 20 times log10(ratio). The ratio is 1000 whispers to one. log10 of 1000 is 3, so the SPL level of a thousand people whispering is only 3 time 20, or 60 dBs.

However, though wikipedia does not state at what distance the SPL level of a whisper was measured, usually we would imagine that it would be a person standing right next to us, or certainly within a meter. Clearly you cannot have a thousand people standing right next to you. Even within a meter of you, considering perhaps two people per square meter including yourself, within a circle of a one meter radius you have only about 3 square meters - room for 5 people besides yourself at the centre. To accommodate a thousand people, you would need a circle with a radius of over twelve meters. Most of those people are going to be at least 6 meters away from you. Wikipedia says "Note that the SPL emitted by an object changes with distance d from the object with 1/d.", so that implies that well over half of these people only contribute a fraction of their potential to the total sound level.

Beyond that, we have all these whispers generating an incoherent pattern of sound waves, sometimes reinforcing each other, and sometimes cancelling each other out, such that by the time this reaches your ears it has only a fraction of the energy that it would posses if everybody whispered in absolutely perfect unison, offset by their distance from you. In the end, the total SPL level is beyond my capability to calculate, but I would just guess that on a practical level it would not reach the level of a normal conversation between two people.

Now, if you want to hear something loud, consider the sound of a thousand hands clapping. Going by the previous example, it is easy to calculate. We begin with an estimate of the sound pressure level of one hand clapping... Oh oh...

Re:Clean Power Plants?

[Radon360]

Actually, extracting hydrogen gas from methane isn't bizarre at all. In fact, using a process known as steam reformation, it is the preferred way of producing hydrogen gas for industrial use because it is more economical than electrolysis. The industrial gas companies (BOC, Linde, APT) all use steam reformation to produce hydrogen.

The only problem with converting methane into hydrogen gas is the same problem you have when you burn methane. It produces carbon dioxide.

The key point to remember about hydrogen is that it is a energy storage medium, not a energy source. Arugably, one could say the same about crude oil as stored sunlight energy, but we didn't have to produce it to use it./p

Dare I say it? A cluster?..

[mi]

In the more distant future huge arrays of hydrogen fueled millimeter turbine engines

Imagine a, oh, whatever, cluster of these!..

Huge arrays?

[Hektor_Troy]

Doesn't turbines get more efficient as they grow in size? I mean, it's not like you'll see power plants use hundreds of tiny steam turbines - they use a few huge ones.

Or am I missing something completely fundamental about the ones MIT's made here?

Re:Huge arrays?

[Max Littlemore]

That's an interseting point. Perhaps the advantage is localised generation rather than isolated power stations. Perhaps they will be used in individual PCs, laptops, etc instead of batteries. I don't get how increasing the friction of a large scale system will increase it's efficiency, and I don't really get where the hydrogen comes from either.

I'd be a lot more exceited about artificial photosynthesis

Re:Huge arrays?

[mainform]

Well, huge ones might be useful on a large scale but they aren't practical on a small scale, hence the smaller turbine :)

First practial use?

[TinBromide]

Who's willing to bet that within a week of these things becoming operational, they're put to use by some MIT nerds making a portable air hockey set?

Re:First practial use?

[edwardpickman]

It is MIT remember, it'll fit inside a matchbook and will have to be played with waldo arms but hey we did it. Wonder how many geek points they get for that one? Next challenge will be to make a Foosball table that will fit on the head of a pin and has to be played with a tunneling electron microscope.

What about our small neighbors?

[Loopy]

This is all well and good but what about all the little bugs that will get shredded in those little turbines? Are they going to paste millimeter-size warning signs? I think it's the least we could do for our tiny houseguests.

Pretty hefty hype there...

[Speare]

Yeah, it COULD revolutionize the whole world as we know it and make the Jetsons' lifestyle seem antiquated, OR...

A toy company puts out a few gimmick Pokemon-tied concept toys long after the end of the Pokemon marketing age, and nobody buys them. Despite the technological benefits of using the power components, the company management gets a sour taste of market performance and buries the whole thing under ten feet of peat and recycles them as firelighters. The technology is not used by other companies for a couple of extra decades because of the patents and other intellectual property entanglements. It is finally redeemed and used in an inadequately-explained Elvis-Presley-tied concept doohickey comes out in 2040 and sells from a Hammacher Schlemmer catalogue for $20K but only if ordered from the seat pocket from LEO during a Virgin Galactic flight.

Moo

[Chacham]

Millimeter Turbins? Must be for really small Muslims.

Re:Moo

[philip_bailey]

Millimeter Turbins? Must be for really small Muslims.

Turbans are worn by Sikhs, not Muslims.

Yep...

[Goonie]

This microturbine research pops up on Slashdot every year or so.

The thermal efficiency is the real killer - according to this post, the expected thermal efficency is somewhere between 3 and 8%.

That's problematic for two reasons - one, a plant made of thousands of these would use way more fuel than one using a conventional piston engine and one generator, and, two, for small-scale apps it means you end up with a massive pile of waste heat to dispose of. As somebody put it - if you want 10 watts of power, that means 100 watts of waste heat to dispose of. Go put your fingers on a 100-watt lightbulb to get an idea of how much heat we're talking about...

Re:Yep...

[CrazyJim1]

Go put your fingers on a 100-watt lightbulb to get an idea of how much heat we're talking about... Ouch, you insensitive clod.

Re:Yep...

[PsiPsiStar]

I'm not sure I totally parse what you're suggesting, but here's the basic concept behind heat engines; (anything that produces movement, and thus possibly electricity, requires a difference between hot and cold. The term for this is a heat engine. They're also called carnot engines. ) "Waste heat" is heat that isn't sufficiently hot compared to the heat sink to generate much energy.

The energy generated by a heat engine is determined by the difference between the heat source and the heat sink. In other words, the difference between hot and cold. While there might be some use for waste heat (i.e. heating houses and roads in cold climates as they did back in my college, and possibly some other applications) anything that makes your heatsink in any way less cold will reduce the efficiency of the primary generator.

Re:Yep...

[Bander]

Since almost everything must deal with dissipating heat, why can't someone invent something that collect the heat and re-use it to generate even more power?

Because of a little thing called the Second Law of Thermodynamics. Basically, if you use the waste heat to generate energy, you do so by exploiting the difference between the heat (probably stored in a medium that doesn't dissipate heat easily) and something else that's cold -- this makes the cold thing warm at the same time your heat storage medium cools down. Eventually, everything in your system reaches a uniform temperature, and the fat lady sings.

If the universe is a closed system... http://en.wikipedia.org/wiki/Heat_death/

More about the Second Law, including math and quotable quotes: http://en.wikipedia.org/wiki/Second_law_of_thermod ynamics/

Re:Yep...

[tftp]

No, it means that you need to turn it on first.

Re:Yep...

[sumdumass]

I think he is trying to suggest somthing like how a coal power plants work. It has a fuel source that heats a liquid (water?) which turns a generator. Then the water cools and it goes through the exhaust of the fuel sorce to captur some of the waist heat and start over.

But i think he is suggesting doing this in combination with existing devices that generate heat like a computer's processor or somthing. then instead of letting the heat disapate into the air, It could create power to help supply the device.

Out side the size and weight issues, I'm not sure enough of the waiste heat could be captured and used effectivley or efficiently enough to make something work like this with any real benifit on the scale of a computer or personal type device. But I think the general idea of reusbg waisted energy is used quite often. It just seems transparent enough the we usualy don't notice.

Re:Yep...

[maxwell demon]

Ok, let's do the math for some realistic example: Say, you want to generate energy from the waste heat of an Athlon 64 3000+ (I've taken this model because that's the first one I've found the required technical data..

Now the maximum temperature allowed for this procesor is 65C (that's 149F, according to Google), or 338K. Now let's assume that it's in a room with 18C (64.4F, according to Google), or 291K. Now let's assume you attach an ideal heat engine to your Athlon 64 (i.e. a heat engine which converts as much heat into usable energy as is allowed by the laws of thermodynamics). Such a heat engine has an efficiency of (338K - 291K)/291 K = 16%. Given that the thermal design power of this processor is 28W to 35W, you'd get an energy output of 4.5W to 5.6W. But note that this assumes

• that you constantly run your processor at maximum allowed temperature (which certainly isn't a good idea; note that lowering the processor's temperature to a more reasonable 40C (104F) would about already halve the ideal efficiency),
• that the heat engine would have a waste heat output of about 24W to 29W, which would inevitably heat up the heat engine's heat sink and thus again reduce the efficiency (unless you do a really good cooling, which probably eats up most of the energy you originally won), and finally
• that you can actually use an ideal heat engine, and a real heat engine would have an even less efficiency (indeed, I'd be surprised if half the theoretical efficiency could be reached).

In short: It's simply not worth the effort.

(BTW, Slashdot ate all my degree signs; it's not my fault that they are missing.)

Gah!

[Anonymous Coward]

A micro-turbine is not a fucking battery! An ultra-capacitor is not a battery! A fuel cell is not a battery!

Size matters

[mdsolar]

The thing about these is that they are so small. The figures given are not all that much greater than the Li ion batteries, so in terms of applications is transportation, one does a whole lot better putting five 5 gal gas cans in your trunk for a 1400 mile range. For compact applications getting more power in a tight spot is a great advantage. If you are carrying a lot of electronics this really helps in reducing the weight. But, I'm not sure you'd want to use these to replace the two stroke in an chainsaw.
--
1000 W/m^2 http://mdsolar.blogspot.com/2007/01/slashdot-users -selling-solar.html

Re:Seriously?!?!

[lendude]

Your humour well has run dry - commence drilling elsewhere.

Something about the numbers doesn't add up...

[GameMaster]

Let me see if I get this straight:

He says that he expects the initial products to be about 500-700 Watt-Hours/kg. and to, potentially, go as high as 1200-1500 Watt-Hours/kg. in the distant future.

My understanding is that this thing is supposed to run off of Hydrogen. It'd almost have, to as many consumer electronics are run indoors and most other fuels I know about give off toxic fumes when used in combustion engines.

Hydrogen has an energy density of ~33.3 Watt-Hours/kg. ( http://hypertextbook.com/facts/2005/MichelleFung.s html/ )

Now, assuming that the weight of the turbine (~4mm square) and packaging is negligible, most of the weight is fuel. In that case, we are looking at an efficiency of 1.5% - 2.1% for the initial models and 3.6% - 4.5% for the extreme upper end of what this guy thinks is foreseeable with this technology. 1.5% - 4.5% efficiency? That's horrible! Remember, pure hydrogen doesn't exist naturally on this planet. You had to spend large amounts of energy in the first place to produce the hydrogen that will be stored in these batteries (how exactly they plan on storing it I don't know because even the best, present day, techniques leak like a sieve because of the extremely small size of the hydrogen molecule).

Don't get me wrong, I can see where people would want something like this. The potential energy density compared to the compact form factor would open up new possibilities for portable equipment. There in lies the problem. The instant gratification of this technology will be almost impossible to fight. If every piece of small electronics had this kind of power source, cell phones, PDAs, laptops, etc. would become leaps-and-bounds more powerful and, at the same time, would be consuming energy at, potential, an exponentially higher rate.

The only way I can see this not becoming ubiquitous is if some other technology, like batteries, beats it to that energy density level. I don't think that's likely to happen because, even at these miserable efficiency rates, liquid fuels still have a massive lead in energy density over even the most promising, potential, battery technology known.

I hope there is an error in my math. Another possibility is that, as is so often the case, the author of the article doesn't have a clue of what he's talking about and had warped the facts of the story. The fact that he has suggested the possibility of replacing full-sized power plants with massive arrays of these turbines gives me hope that that's the case. If any of you have a correction for my math, please let me know.

-GameMaster

Re:Wow, really?!?

[fireboy1919]

Yeah. Really silly, huh?

But, just for fun (since I can't remember), which law of thermodynamics does the production of power violate?

I'm looking at 'em, but I can't find a law of conservation of power. I'm sure that's the one you meant, though, right.

Hmm... I guess I'm going to have to walk to work tomorrow. My car is currently sitting in the driveway producing no power (since none of it's components are doing any work at all), and thanks to xaxxon's newly discovered law of conservation of power, that means it isn't going to be producing power in the future, since it's previous means of doing so was by using stored energy rather than any form of power.

Incidentally, I think I'm going to have to cut this post short. I imagine it's not going to be too long before somebody realizes that computers have nonconstant power systems and it stops working. I just pray nobody gets around to doing the same to all life on this planet.

Turbans are worn by Sikhs AND Muslims.

[giafly]

Millimeter Turbins? Must be for really small Muslims.

Turbans are worn by Sikhs, not Muslims.

Turbans are worn by Muslim scholars (ulema) in many countries. Also by lots of other people.

Re:Quiz Time

[Gabrill]

You flip the 1st switch. Wait 10 minuts. Flip it off and flip on the next switch. Go in the room. If the light is on, it's the second switch. If the light is off and hot its the first switch. If it's off and cold, it's the third switch.

You replying to the burning your finger thread tipped me off.

microgenerators

[mdsolar]

At least one of your objections has already been covered on slashdot. http://science.slashdot.org/article.pl?sid=04/11/2 5/1331227

This link also covers the effort reported in the present post. Your comment on the efficiency of the proposed turbine anticipates some comments here. http://science.slashdot.org/comments.pl?sid=130810 &cid=10918320.

It was one of Bucky Fuller's favorite things to point out that heat management becomes easier with scale since the ratio of surface area (where heat escapes)-to-volume (where heat is stored) goes down in inverse proportion to the increase in linear dimension. This is why he felt that enclosing cities with his domes would be a good idea.
--
Take the solar scale advantage: http://mdsolar.blogspot.com/2007/01/slashdot-users -selling-solar.html

Info on IHI Dynajet 2.6 genset mentioned in OP

[mnemotronic]

The MIT microturbine is interesting, but in the "what can you do for me today" category, the IHI Dynajet caught my eye.

Product PDF :: http://www.ihi.co.jp/ihi/file/technologygihou2/100 04_6.pdf which mentions this interesting phrase:

The Dynajet 2.6 is also undergoing development of mobile dry toilets featuring its Merit (3).

From :: http://www.ufto.com/clients-only/uftonotes02.html

Originally built for military and civilian use, IHI's Dynajet 2.6 KW microturbine genset is selling commercially in Japan is 1.2 million Yen (about $9000) "for use in Japan only" (kerosene fuel). There are no plans for export. They don't have a natural gas version. Very little information is available, though I do have a 2-page product description and spec sheet (*available). The unit measures 30"x10"x11" and weighs 140 lb. [The contact at IHI prefers not to be listed.]

from (PDF) :: http://www.jaif.or.jp/english/aij/member/2003/PDF/ May.pdf

Last year, about 90,000 small power generators were sold in Japan. Japanese manufacturers are now working hard to expand their sales and add new models to their product lines. IHI Aerospace, for example, has released a portable model, the Dynajet 2.6, driven by a microgas turbine. Fueled by kerosene, which is easier to store than gasoline, the generator retails for ¥1.2-1.3 million ($10,100-10,900). It is the lightest gas turbine-driven model on the market. The company is also developing a cogeneration system that utilizes waste heat from gas turbines.