Slashdot Mirror
Capturing Waste Heat with Quantum Mechanics
TheMatt writes: "There is a summary of a Phys.Rev.Lett. article up at Nature Science Update that describes a design for a 'quantum afterburner' that would improve the efficiency of an Otto engine. It improves the efficiency by using a laser and maser to extract energy from the hot exhaust of the engine. In fact, the process could enhance performance beyond that of the "ideal" Otto engine."
I used a laser and a maser to extract energy from the waste heat generated by my Athlon. I've been running everything in my house but my computer off that exhaust tap!
They that would sacrifice their
So I get that you convert waste heat into light, first with the maser to get microwaves, and then with the laser to get some other wavelength. What then?
Frankly I reason simply to Prepare orthogonal system tenacity.
Why not simply use an adsorption type "refrigeration" (ammonium hydroxide & water) system to cool the air/fuel intake charge to make it more dense and get some more efficiency out of the internal combustion engine? The waste heat going out the exhaust and radiator could run the adsorption-cycle cooling system.
Has anyone else noticed a story about linuxworld that appeared on the front page a few minutes ago, which disappeared by the time I hit submit on my comment? It's kinda freaky. (I'm posting anon so mod's don't burn me for this and so they don't have to.)
The hot gases belching out of your car's exhaust are not just useless waste. They are a laser waiting to happen, says physicist Marlan Scully
I sure hope this doesn't change the global warming going on or all that beachfront-after-the polar-icecaps-melt property I bought will remain high and dry (scuba diving in downtown LA whoohooooo)
I Am My Own Worst Enemy
First off, so-called gas-dynamic lasers have been known for years if not decades, so this is old news. Secondly, the energy efficiency is not increased beyond the theoretical limit of an Otto engine.
Let me be #4.
...at least on the scoop part. Has anyone here actually looked at the Slash code? I could take a dump on a bunch of old IBM punch cards, rub them together, and come up with something better.
I think this idea is genial, but the cost/effeciency on a car would be "hard" to achieve. What I find interesting, is that this duo laser/maser only require heat from an exaust : nearly the same thing as evaporated water from nuclear reactor. This could lead to a better efficiency of nuclear reactor, and the cost of such laser/maser would be minimal compared to electricity generated by that system.
Does anyone have a username/password for the APS site to view the article? the usual cypherpunks/cypherpunks doesn't work.
Ideally, if the excess heat was converted back into electricity, I wouldn't need to waste electricity on the fan, and I could substantially extend my battery life. Oh well, I can still dream.
So add this to the rest of the long list of inventive ideas that the U.S. Government would lose money/jobs by backing... Why don't we start with some of the simple non fossil fuel based solutions that have been offered as a source of simple household electricity? Why not cash in on some of the environmentally friendly solutions that get power from forces like gravity? ie: floating bouies (sp?) in the ocean that drive a piston when the tide comes up, panels that are driven back by waves that would server a dual purpose on coastal areas that are struggling with problems of erosion. Eliminate excess pollution and excess spending first where the solution is both cheap and practical or focus your attention first on the government to first allow such ideas to actually be implemented.
In this house you will obey the laws of thermodynamics! -Homer
But really are they saying they can improve the efficiency of a Carnot engine, or just the Otto cycle?
Veramocor
My first thought when reading this title (nothing to do with the article:
"Producing Hot Air with Quantum Mechanics."
-Paul Komarek
Cars with frickin' laser beams on their heads .. And for once I might actually get them :-)
I am Slashdot. Are you Slashdot as well?
Can be found here (in PDF form), for all those who like reading physicists physics.
There's no reason for a sig here.
Hmmm... could be modified to improve my car's performance...?
--Metrollica
After reading the article, its not as far fetched as it sounds, atleast at a low efficiency.
The problem as I see it though is this, what is the engine going to do with the laser light anyway? Laser light isnt that usefull in a car as an energy source. And I cant see the intensity of light being enough to do something cool, like dissasociate water to H2 and O. This is probably in the "neat-things" file for quite some time. Though maybe they can use this technology for fixed poer generation (coal, nuclear) where the gasses temperatures are higher and there is more volume.
Anyone who considers arithmetical methods of producing random numbers is, of course, in a state of sin.-John von Neumann
If you check the front page, the LinuxWorld story was already posted earlier today. Tim or whoever posted it must have relized it was a duplicate and pulled it down instead of having people post comments on it.
Maybe we can say the editors have improved.
Do Quantum Mechanics work for Maxtor now?
General Relativity: Space-time tells matter where to go; Matter tells space-time what shape to be.
Wow. This is a neat idea. But not really a new one. Not new that is in terms of trying to find some way to use all the wasted energy. Right now we are still using technologies that are terribly inefficient. All this heat going out the exhaust pipe of our vehicles. What about the heat exhaust from your furnace? Your gas water heater? It seems that if we can generate X amount of energy, we should be able to use every last scrap of it in some way, rather than just simply releasing it into the environment. Does anyone know of any other projects out there to reclaim and use some of this lost energy?
I wonder if I could then direct that laser at the moron who's tailgating me while yacking on his cell phone. b-)
:::Horrendous Experiences Make Amusing Anecdotes:::
...The Fast and the Furious? I mean they had everything else: NOS stickers, neon lights on the undercarriage, ad naseum. Why not a laser in the engine?
-- ;-)
Kuro5hin.org: where the good times never end.
the effective thermodynamics for a heat angine are:
/necessarily/ mean a higher temperature delta or work done.
(t1-t2)/t2 where t1 is the peak temperature achieved by the combustion process, and t2 is the temperature of the gasses when they've done working.
this formula is deceptively simple but do not be fooled. it exlains why the maximum theoretical efficiency of your car is not much better than 30%.
cooler intake gas only affects some flow dynamics and of course charge density. but that does not
It'll make me feel like James Bond, without being British, or having so many STD's...
The dog! The Buddha-Nature!
.M.
The perfect manifestation, the command of truth.
If, for a moment, you fall into relativity,
You are a dead man!
~
MU!
Yes and do you think they know the physics behind articles on black holes ? Or electronics behind articles on CPUs ? No but it sounds technical and cool
So, logically then, laser beams could be powered by farts, right? Excited gas molecules. Of course they'd have to be really HOT farts...
Could the exhaust gas heat be used to make a car heater that doesn't take so long to fire up?
But MIRACL is using a far more reactive fuel at far higher temperatures than anything you find in auto exhaust.
If you can get enough energy out of the exhaust laser, you can use the radiation pressure of the light to get the car to go faster!
(I know the pressure produced would be minimal - the sun's light generates a force of what? 80 tonnes?)
This would sure give a new meaning to 'back-firing'.
Er, I otto nae break them, anyway.
You see? You see? Your stupid minds! Stupid! Stupid!
Are _ external _ combustion engines that can be run (with appropriate mods) from ANY heat difference.
Although displaced by the internal combustion engine, the stirling engine has still continued to advance. Modern Stirling engines can be smaller than a coin & used in satellites, or larger than a house.
They are ideal for the recovery of energy from waste heat, exhaust's, furnace flues, domestic heat, etc.
Just think, no more tailgaters once they get these lasers mounted!
Thinking of jacking my car? Think again! I'll shoot you with my..uh...mini me...stop humping the...
If this makes it into your average car, would you have to take it to a normal mechanic AND a quantum mechanic? The price of the devices used in research had better come down before it happens.
I can see it now...
QM: (Wipes hands on oily rag) Well, if you lookee here, yer muffler wall is causing the maser beam to create destructive interference.
Car owner: uhuh.
QM: That, combined with the alignment of the quantum magnetic dipole is causing yer car to stall.
Car owner: But how much will it cost?
QM: Yer salary fer the next two years.
I can see a possible application for this: speed detector jamming. Lots of people buy radar/laser/microwave detectors for their cars to try to beat the cops. There are even some on the market which claim to scramble the speed detector in such a way to disable the readout. With the quantum laser/maser setup, the faster you drive, the hotter your exhaust, and the hotter your exhaust, the more ferociously you jam anyone attempting to gauge your speed. Great!
Quantum Mechanics has been known to be a time-trasnlation invariant theory. In layman's term, it means that you can run the clock backwards and everything is fine. There is no "irreversible" process. (For the jargon-empowered, QM does not have a natural "arrow of time").
However, we know the Thermodynamics 2nd law tells us that even *ideal* processes are essentially irreversible if we do work, i.e. waste heat is inevitable.
So the idea to use QM to improve this "ideal"-ness (classically speaking) is an intersting step towards understanding the *other* big issue in science : which is how the 2nd Law fits into the grand scheme of things. (Grand Unified Theories do not incorporate 2nd law since microscopically are processes are essentially reversible. The 2nd law drove many people nuts, including Roger Penrose.)
So the point of the paper is not "get more $$$" for you engine. It's an interesting gedenken-experiment (sp?) that proves a point.
Mode (3) smart-aleck mode. Press * to return to main menu.
So, um, how do you use this combo maser/laser beam to do soemthing usefull?
If Mr. Edison had thought smarter he wouldn't sweat as much. --Nikola Tesla
if you could route the laser back to the combustion chamber, you could use it in turn to burn extra fuel (similar to the way nos affects combustion). the increased fuel being burned would create more exhaust. wash, rinse, repeat until nearly 100% of the fuel in the chamber is being burned and the car reaches maximum feasible efficiency. probably not all that feasible though, since routing lasers is expensive at best.
.cig - what you do after winning a good flame war
"Unask the question"
If I understood this article correctly, the laser transforms heat (disorganized energy) into laser light (more organized?). Wouldn't this cause a net decrease on entropy in the system?
Something similar to this was posted a bit ago on Slashdot, but what the hell.
With a turbine engine, kinetic energy is extracted by hot-air through turbines, which in turn suck in air, compress it, combust it, etc. Cyclic compression and expulsion creates thrust, or rotational energy on the turbine shaft (which is what turbo-prop airplanes, APU's, helicopters and generators use).
This technology might have applicability for turbines which use rotational energy from the shaft. For instance, the APU on a 777 is a fairly large turbine engine. Would it be possible to lower its running RPM by using converted heat from the exaust stream as a secondary source of power? This would of course lower fuel consumption while the APU is running, as well as extend the time between overhaul for it.
Anyhow, essentially: this technology, if viable, could have serious use within turbine engines, since they waste a significant amount of heat in operation.
Hey dude guess what?
SLASHDOT AUTOMATICALLY CUTS OFF LONG POSTS!
Yah yah yah, big surprise eh?
Your posts take about what, half a second to scroll by? Oh wait, not even that long!
Jeez. Get an original troll for crying out loud! No wonder CT gets fouled up and starts banning people, he has to put up with unoriginal uncreative CRAP like what you put out!
Hey you know what? I think that the sheer STUPIDITY of your post is FAR more annoying then any attempted troll value that you seek to put into it. Keep on showing yourself to be an unoriginal dunderhead with no sense of creativity at all and I guarantee you that you will piss off far more people then you will by seeking to attempt these pathetic little trolls of yours.
Unoriginal, undaring, uncreative, none risky, unoffensive. The Amish are more offensive then your pathetic little attempt at a troll.
Need help treating your acne? Come here!
So, what's stopping you?
Home Power magazine is a good place to start for ideas and things.
And if you come up with something that runs a net surplus, sell the power back to your local government mandated utility. Most government grants of monopoly for electrical power include a requirement that the utility buy back what you as a private individual produce.
Not all, you can be sure, but HomePower has good information sources on that.
You could, of course, spend a decade lobying governments and buying influence with the politicians, but that would just make you another Enron. It's much more efficient to just build it yourself.
Bob-
The Ludwig von Mises Institute. The reasoning individuals economics
The whole idea seems like a good way to write a paper, get published and generate hot air, but not a good way to increase energy efficiency. Kinda like our current projects to build a fusion reactor ("We've already got one, fer Christ's sake! It's called the sun.").
There is no trap so deadly as the trap you set for yourself
-Raymond Chandler, The Long Goodbye
Yes, we do, actually.
hahah you called someone a "dunderhead".
And all these years I thought quantum mechanics just meant when you get one part on your car fixed, another part breaks.
and it is a pretty interesting idea. I'm not sure about the practical feasibility of the concept for reasons I'll get into below. But, it shows that quantum effects might be usefully exploited to make better engines and will probably prompt a fair amount of thought and experiment into the matter.
... thanks lameness filter ... less than signs could never be useful).
... more molecules must be in one of the upper states than in the lower states. However, in a gas at thermal equilibrium, this is usually not the case ... the probabiliy of finding a given quantum state in state with energy E is proportional to exp(-E / kT ). Here, k is Boltmann's constant and T is the ambient temperature. At low temperatures, the ground state will be where most of the molecules are.
... "b" molecules to preferentially transistion into the ground state (state "c"). However, the "a" population won't be able to come to equilbrium that fast (provided the spontaneous emission rate is sufficiently low and the maser cavity isn't tuned to enhance the transition rate out of "a" state). This net impact of the maser is to create a population inversion between the "a" and "b" states. By passing the non-thermal maser cooled gas into a laser cavity tuned to the "a"-"b" transition, this inversion can be extracted as laser energy. This is the quantum afterburner part.
... involving passing the gas back and forth through two pistons. I'm pretty sure that materials and a simplified engine design could be made to validate the claims though.
Warning: Ph.D. punditry follows.
Suppose a molecule has three possible states ("a", "b" and "c") with energies E_c, E_b, E_a respectively (E_c is the ground state and E_b is the between E_a and E_c
Suppose further, microwave (maser) energy transitions are possible from state "b" to "c". Optical (laser) transitions are possible from "a" to "b".
For lasing to occur, you must have a population inversion
If the hot exhaust gas is first passed through a maser cavity tuned to the "b"-"c" transition containing a radiation field at the temperature of the cold reservior, the "b" and "c" populations will quickly come to thermal equilibrium with the low temperature radiation field
From a quantum standpoint, nothing is particularly new here. Using rapid cooling of a selective population to create inversion is pretty unique but nothing that can't be explained with the standard laser rate equations.
From a purely statistical mechanics standpoint, the net effect is to extract extra useful work from internal degrees of freedom of the working fluid. Statistical mechanics is not my forte so I can't really say if this is particularly out there.
From a practical standpoint, it might be hard to find gases at engine temperatures and gas pressures where the low spontaneous emission lifetimes necessary to sustain the inversion is possible. My intuition says that collisional de-excitation (high temp and pressures) would wipe out the inversion. Also, the exact scheme discussed in the paper is more complicated
As a thought experiment, though, this shows that it may be possible to improve the efficiency of an Otto engine. (By the way, the paper notes that a Carnot cycle efficiency doesn't get a boost from the technique.)
Kevin
so where does the energy for the laser and maser come from.
Every time I see that Ben Franklin quote, I'm reminded that while many Americans risked (and lost) their lives to throw off British rule, Franklin "suffered" by staying in France during the revolution. I guess he didn't mind his own safety being secure while other people fought. Hypocrite.
-jon
Remember Amalek.
Nit to pick: you mean time-reversal invariance, not time-translation. Symmetry under time-translation is related to conservation of energy, not reversibility.
Not to start whining again about the second law of theromodynamics, but the laser and the maser also have to be powered. Since one uses the laser to depopulate the second excited level, the laser emission has to come from the 1-> 0 transistion. The emitted laser emission is probably of less energy than the first one.
Also laser and maser have to be powered and somehow I think this takes a whole lot of energy more than a normal car enigine can supply.
Then also the fact remains as already noticed by other replies what does one want to do with the laser-light obtained? (this also follows the 2nd Law)
Same with classical mechanics, and more so, as QM has the "destructive measurement" hypothesis, that by merely measuring that an object is in a given state, you collapse any state superposition in which it might have been. Besides, Statistical Physics and Thermodynamics have borrowed quite a lot from QM (particles being in given states among a number of possible ones, etc.)
Yes, this comes from the fact that there exists a great many more possibilities that waste heat will be irrecoverably produced. It might stay in a usable form, just as you might open a bottle of ink under water, and the ink might flow out and then all crawl back into said bottle. It is just highly unlikely.
There is no need for an arrow of time at the microscopic level for that.
As for the paper itself, if I understand the summary correctly, it is ingenious but I'd look for a catch, such as the maser requiring at least as much power to function as that you can extract from the waste heat... Wouldn't that be annoying?
(And many thanks to all the scientists who publish on arXiv).
"Ya see, we're kinda afraid that if we observe the problem it might alter the system and give you a totally different problem..."
"Well, we're not quite sure where your car is, but we do know exactly how fast it's moving... Would you prefer the other way around? 'Cause I can do that instead if you want..."
--
Damn the Emperor!
Just build metal cases and put processors surfaces in contact with them. A large metal surface can absorb a -huge- amount of thermal energy, but laptop producers don't do that because of higher costs: plastic is cheaper, and lower weight helps sales.
Whilst this may be true for "plain old QM" as embodied in the Schrodinger equation, for example, the Quantum Field Theories of modern particle physics certainly are not time-reversal invariant.
QFTs such as the standard model are provably invariant under a symmetry known as CPT. This is the combination of three individual symmetry operations:-
The decay of neutral K-mesons (or kaons) measurably violates CP This implies a violation of T if CPT is to be preserved. The Standard Model (Glashow-Weinberg-Salam) incorporates CP violation, albeit in a kludgy manner (imaginary values in the Cabibbo-Kobayashi-Maskawa (CKM) mixing matrix)
Google for "CP-violation" for reference links
Paul Davies wrote a lay-persons book exploring the different "natural arrows of time" in physics including CP violation and 2nd Law of thermodynamics called (duh!) "The Arrow of Time" although I haven't read it (but have read other of his books).
OT: Flanders and Swann wrote a song (v. funny) about the first and second laws of thermodynamics.
if I understand correctly, this would amount
to a kW range infrared laser available
"for free" in the car. You can then
shoot down birds, 007 style (gives a new meaning to roadkill)
do some welding in the car while driving
punish tailgaters on the spot
have a very trendy cigarette lighter that saves some fuel
...
Google passes Turing test : see my journal
... you can always run SETI@Home.
--
"By the way if anyone here is in advertising or marketing... kill yourself." -- Bill Hicks
"ideal" Otto engine.
Would this power Turkey of the late 19th century, or the school bus on the Simpsons?
Jimmy _______ | | | \__/
If you are the military that is.
1. Extracting waste heat reduces vehicle heat signature.
2. Even an extra few miles per gallon of feul means substantially less logistic headaches. The Gulf War, for example, was considered a triumph of efficient logitics because the Abram tanks were incredibly feul thirsty.
Ofcourse it should be "you CAN'T convert all heat energy..." rather than "you CAN convert..."
Gentlemen, you can't fight in here, this is the War Room!
Doesn't anybody else find it at least slightly funny that someone is proposing putting a Quantum Afterburner (TM) on a piston engine, the essential design of which is 125 years old? After all, there are other ways to recover waste heat in the exhaust that we could be using now, but aren't. Peltier junctions could be used to generate electricity to supplement or replace the function of the alternator once the engine was hot. Someone else here mentioned stirling engines. Maybe that'd be another way to increase the efficiency. Again, maybe you could drive the alternator with it. Of course, the alternator only uses maybe 1 or 2 horsepower anyway, so even eliminating that drag on the engine is only going to be a small improvement.
Than again... how many horsepower does a car use when cruising? Maybe eliminating 1 or 2 horsepower would make a difference. I would assume that this Quantum Afterburner (TM) would be able to recover a much greater amount of the waste heat, too, so maybe it would make quite a difference.
P.S. -- before anybody starts to rant on me for using horsepower, remember, there are metric horsepower too! According to my unit converter, one horsepower equals 1.01387 metric horsepower. Guess the French have different sized horses than the English! Cheers!
I'm no engine expert, but doesn't anything that impedes the flow of exhaust gasses interfere with the internal combustion process, making the engine less efficient? The two-poston contraption these guys are using would certainly seem to fall into that category, if they tacked it into the car's tailpipe.
Patrick Doyle
I mod down every jackass who puts his moderation policy in his sig. Oh, wait a sec....
Alas *this* paper has nothing to do with violating 2nd law. It is not a gedanken experiment either, its a real device. I guess you should read the article from time to time.
Gentlemen, you can't fight in here, this is the War Room!
Let's say that you're trying to maximize power/weight ratio, first and foremost. Well, in that case, you have to rule out copper heat exchangers. Their thermal conductivity--compared to their mass--isn't so great. Ok, then. Now you're stuck with something like aluminum.
Oh. Shucks. If you get much above 900 degrees F, then the aluminum cannot withstand much pressure differential between the working gas side and the coolant side.
If you reduce the pressure differential, then power density suffers tremendously. A 1 horsepower (750ish watt) engine could wind up being enormous--even if you use helium.
Ok. So then you decide to be nicer, temperature wise, and get meaner, pressure wise. Well, then, another nasty ratio comes to bear:
Heat engine math is like audio amplifier math. The temperature on any scale measures something significant, but in the thermodynamics of it all, what requires attention is akin to dB of audio signals. It is logarithmic. But, hey. Let's not get so fancy. The bottom line in this part of the discussion is that you need a maximal difference in hot-side temp and cold-side temp DIVIDED BY THE ABSOLUTE TEMP, i.e., Rankine or Kelvin. Picture in your mind an Excel (cowering) OpenOffice type of fancy schmancy bar graph with two regions within that one bar on the graph. (Remember: We're talking about absolute temperature now.) The height of that bar that is the temp difference is something that needs to be divided by the height of the whole bar in order to be significant to engine design.
Just reduce that "numerator" a little bit, and the hopelessness of efficiency is amplified by the denominator's mean size.
Why figure this way? Because Carnot compels it. His opinion was that the best efficiency that you could hope to achieve would be the ratio of the temp-difference part of that bargraph bar compared to the height of the whole bar.
In a nutshell, using aluminum is going to clobber both the power density and the hope for energy efficiency.
In this subargument of mine, the bottom line is that affordible materials compel an unpleasant tradeoff between various design goals.
There is always an unpleasant tradeoff, and none of it occurs in an economic vacuum.
In, say, a diesel engine (which thermodynamics geeks like to call a CIDI, for compression ignition, direct injection), the maturity of the engineering is such that there is rational hope for efficiencies above 30%, and the power density, though not wonderful, is tolerable.
Just as Microsoft chases capital away from every Word Perfect wannabe, diesel chases capital away from "exhaust scavengers" in Otto cycle, which isn't as much of a digression as it appears.
I have studied the recent history of commercial Stirling cycle engine development. Big names like Cummins have piddled around some and developed nice stuff. It is useful for what I call "Stirling-on-a-stick" technology, wherein a paraboloid reflector concentrates sunlight at the hot side of a Stirling engine. Still, Cummins dropped the project.
Ok. Now for something completely different...
I get suspicious every time someone claims to outsmart Carnot--this is no exception, and neither is the laser. Oh, sure. People like Ralph Nader can get applause by saying that huge energy companies are so decadent that you'd swear that their number one purpose in life is to heat the heavens! That is becaus of Carnot's pessimism. When you think you can beat him, I think you're trying to kid me.
I offer a caviat, and this is where it gets interesting again.
Let's say that you put a whole bunch of heat engines in a series of heat exchanges, starting with, say, diesel (CIDI). Engine number two uses exhaust gas. What the heck? Engine number 2.1 uses radiator liquid just to be thorough. If the best you can hope to achieve from engine number one is a thermodynamic efficiency of 30%, then 70% is up for grabs. Get 20% of that, which is .2*.7=.14 of the whole. Not bad. You've already topped 42%. During the next go-round ("engine number three") you'd be darned lucky to achieve 8% of the stuff going in (which was only 58% of the Engine #1's input heat). So now you're talking about .08*.58=.046. During the third stage, you've only scavenged 4.6% of the whole-system input heat.
That, in turn, gets added onto the 42% from before. It's not a miracle to get this, 42% + 4.6% = almost 47%. Because of engine number "2.1", you just might have a chance to top 50% if you do it in northern Canada in the winter. But it is darned expensive even to try.
If you're that desperate for energy, you might as well look into alternatives. I politely request that you don't stick it where the sun don't shine. ;-) IMHO, the best place for a Stirling engine is on a stick!
"Yes, this comes from the fact that there exists a great many more possibilities that waste heat will be irrecoverably produced. "
.... there's an arrow of time. Without one, my reverse argument makes as much sense as your forward time argument, the fact the reverse time argument doesn't apply is in fact a restatement of the arrow of time concept.
"There is no need for an arrow of time at the microscopic level for that. "
Not so, because this argument can be applied equally well in reverse time, although there's quite a lot of subtlety in ensuring you're applying it right.
Consider this:
A low entropy system - where did it come from? There are many more high-entropy possibilites and disordered states which could have given rise to our (low entropy) system than there are ordered/low entropy ones. It's highly unlikely therefore that entropy will increase spontaneously in forward-time.
So
it is absolutely possible to increase the efficincy of even a perfect otto engine. that is because the best otto engine could never convert more than ~70% (?) of the input energy into mechanical output.
what it comes down to is that if you take just the exhaust pipe as a seperate system you have a differential in temperature, and such an energy potential can always be used to produce useful work
forgot about the less than sign in the title... seems like that should be automatically converted to < automatically with plain text submissions
oh well
Sort of on topic, considering the number of comments being posted about heatsink fans (even though the article has little to do with it): why noone ever figured out a way to use the hot air being expelled by the system fan to turn something that would generate electricity. Can't some of it be recycled back to power the system?
Alright, this thing is still strictly theoretical, right?
Correct me if I'm wrong, but isn't the internal combustion engine at the beginning of it's decline now? I mean, how long will it be before this effect is put to use? A decade? More?
I suppose since the article keeps talking about waste heat generated by the engine, rather than any features particular to the engine, there might be other uses than prolonging the life of a technology...but then why put everything in terms of "the Otto engine?"
Well, anyhow, I'm sure car buffs 20 or 30 years from now will be glad to have such a device to help keep their old 20th century vehicles street-legal.
You use the maser to jam police radar, and the laser to jam
police laser speed measurement devices. If smokie
gets on your tail, you use the big laser to smoke him!
is the name of the process used in CO_2 lasers, for instance.
The "mach cones" you see in the exhaust of a
military jet during takeoff are a nonnnnnnn'coherent example of the
same phenomenon. Sorry about the anon.
related to the Otto Pilot?
You never really know how close to the edge you can go until you fall off.
Off topic, but the second law of thermodynamics only applies to systems in equilibrium with their active environment.
G. Nicolis and I. Prigogine, (1987), Exploring Complexity, Piper, Munich, 1987.
Gregoire Nicolis, "Physics of far-from-equilibrium systems and self-organization," Chapter 11 in Paul Davies, Ed., The New Physics, Cambridge University Press, Cambridge, 1989, p. 317-347.
Ilya Prigogine, The End of Certainty: Time, Chaos, and the New Laws of Nature, Free Press, New York, 1996, 1997.
Systems in disequilibrium with their environment are allowed to:
1. self-order
2. self-oscillate or self-rotate
3. output more energy than the operator inputs (the extra energy is received from its active environment)
4. power itself and its loads simultaniously
5. exhibit negentropy
Just a little FYI to get you up to speed with modern physics.
The only problem is these "quantum afterburners" are probably not going to be light... or small... or cheap... and they'd stop you at the airport and take it apart thinking it was a bomb, and then you'd be out a lot of money. Did you know they sell extra batteries for laptops? Maybe that's a better route! :-)
"Da ist ein Technölüst in mein Unterpanten!"
The Second Law is really a statement about probabilities and how you count macrostates and microstates, and so doesn't have to be present in microscopic physical laws because it doesn't mean much there anyway.
Hey, I never said it would be super efficient. Just way more efficient than sticking a laser on a tail pipe. For hybrid cars, where every Wh counts, stirling engines may be worth looking into though.
And yes, the best place for a Stirling engine is on a stick (above a parabolic reflector).
There is no trap so deadly as the trap you set for yourself
-Raymond Chandler, The Long Goodbye
It was the French who kept the British away from their reinforcements, otherwise the Colonists army would've been crushed by the second wave. As such, don't you think it was better for Franklin to be there to plead the Colonists case instead of dying in the mud? Without France, all the people who died would've died in vain.
Ah, finally an explanation for "The Emperor's New Mind"!
link to paper, read and then we discuss
yes. you are right of course. I was talking about plain vanilla QM. In QFT, CFT is the symmetry that we should care about.
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See, you have to heat the interior, and that's done with a heat exchanger that uses the engine's "waste" heat. When it gets down to -20C or so, every drop of gasoline is either causing motion or heating the cab. The exhaust coming out the tailpipe isn't even lukewarm.
Admittedly efficiency sucks in the summer, but I just thought it was worth remembering that for half the year, that "waste" heat is not "waste" in places like Canada.
thanks lameness filter ... less than signs could never be useful).
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Its called a turbo.
Granted its much less efficient than a quantum level interaction but thats what a turbo does; reuse the exhaust causes to spin up a turbine. The turbines used then to compress air coming into the engine and raise the efficiency of the engine.
I think all that jargon is what I called "do work". :P
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Heh.
:P.
RP came over here to Chicago to give a colloquim once and he went about telling us how all current theories (string theory, inflation, cosmology etc) are all wrong because they do not incorporate/violate the 2nd law in some form. There was a lot of glancing of faces and rolling of eyes
It was a very provocative talk though.
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Why hasn't anyone mentioned applying this technology to fuel cells?
What's powering the lazer-mazer combo?
Say, what's with thi anti Cmmander tach rhetoric?
I think instead of trying something fancy with a car's exhaust, someone should redevelope the axle and break mechanisims in cars so that they can return some of the wasted energy from stopping and going.
One example would be some what low tech. When ever you put on the brakes after being in motion, you would have some of that energy caught in a spring mechanisim. A coil spring or something? Now lets say you are at a red light when the spring is fully charged. As soon as you press on the gas, you get a little boost from the spring to save on having to burn up the gas.
Well others could also argue that it wouldn't matter because every time someone comes up with something that can help the world get off the "OIL Burning" high. Big oil comes in and buys them out. Who knonws what really goes on when alot of money is at stake?