'Thermal cloak' designed, could solve major chip, spacecraft issues Top boffins in France have come up with a radical new take on the "cloaking" and invisible-shed physics breakthroughs of recent years. They have designed a technology which instead of bending microwaves or light can shield an object from heat - or concentrate heat upon it. Heat 'cloak' concept. Credit: Sebastien Guenneau, …
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Not sort of like. Conventional insulation simply slows down heat transfer, but given enough time some heat *will* get through.
If the article's claims are accurate this new system completely redirects heat flow so shielded areas will never get warmer however long you wait. And can do completely new tricks, like concentrating heat.
Oh no it doesn't</pantomime>
Read the linked paper, the temperature inside the shielded region rises to T/2 in <2 seconds, further this isn't really a 2D design as the entire object, including the shielded region is clearly dissipating heat elsewhere, if this was a closed system it would simply delay heat transmission to the shielded parts.
This is exactly like the sort of thermal insulation you would find in a thermos flask, where most of the energy from a heat source on one side of the flask will be channelled around the flask rather than through it, ditto for the claims of a 'heat concentrator' effect which really should have rung your entropy bell.
Presumably more useful to the world in general would be the rapid heating/cooling potential which could be used to pasturise water using (for example) the sun as a heat source. Or perhaps use it to desalinate water. I'm thinking of pushing to heat into one area (used to heat the water) from another area (used to condense it back again). I'm no expert (obviously).
It's unclear (to me, anyway) as to whether it's pulling heat from the cool area, or just directing it away. Condensing the steam in the cool area would, obviously, warm up that area.
If it is cooling the cool area, effectively pumping the heat into the hot area, then coupling it to a stirling engine might be interesting.
this could be very big.. if it works like i understand it, then low grade heat (i.e. recycled waste heat , the energy in tepid water, warm air etc) could be concentrated to a point where it was usable.. goodbye not very convincing stirling engine, hello solid state heat concentrator :)
Yessir, the ability to concentrate heat flows should have some interesting potential for waste heat in power generation. The applications in the article are neat and all, but the impact in the power industry could be huge.
imagine being able to use all of the (no-longer?) waste heat in say.. the London Underground. the tunnels could be cooled to a comfortable degree, and the heat concentrated to generate power.. this could revolutionize everything.
Global Warming Angle: Could this be used to concentrate atmospheric heat? suck 1-2K per cubic foot of atmosphere out of the air, channel it into a (bloody great) Stirling engine...
I hope this is as we read it, and Maxwell's Demon has been tamed.
Story For Scientific Breakthrough You Will Never Hear Of Again Blueprint
"Scientists at ... Have Invented <Insert Popular Futuristic Sci-Fi Technology Here>"
Blah blah <sci-fi references> blah blah <as seen on TV> blah blah. Blah blah speculation blah. <Insert Caveat Quickly And Move On> blah blah blah.
Available Caveats:
1. Only works on quantum scales
2. Only works on paper
3. Only works in two dimensions
4. Doesn't work
The register doesn't suffer from this, but this type of story is crack to the tabloids making up virtually their entire "science" reporting along with the "X Causes/Prevents <insert ailment>" blueprint. Always such significant science news about something never to be heard of again!
Ha ha ha I love it! I have to add:
5. Only works on our lab rats / test volounteers / room-temperature fusion reactor.
I've also frequently seen:
"If <scaled> such a breakthrough would permit <A.C.Clarke 'magic' technology>"
..as in "An aeroplane powered by such a device would reduce flight time from London to New York to 20 minutes, and use less than 10 grammes of fuel" etc.
The Second Law of Thermodynamics, which you'd have to be a braver man than me to break, was originally formulated as:
"No process is possible whose sole result is the transfer of heat from a body of lower temperature to a body of higher temperature."
And of course, Scotty's Law states:
"Ye Cannae change the laws of physics, Jim"
In other words, you can't 'concentrate' heat, to do sow ould violate the second law. You may be able to influence the flow of heat by judicious choice of materials, but the end result is always that heat flows from hot to cold. Thanks to conduction, convection and radiation, once you stop pumping heat into it, the entire system will eventually end up at the same temperature. Anyone who claims otherwise is selling you snake oil.
I'm sceptical..... its the radiation part that interests me... radiation can be reflected & absorbed....
vacuum, two masses, one has a silvered/reflective radiator, one has blackened radiator
now what happens? how can they both end up the same temperature if one will absorb more radiation than the other?
anon as I am not a physicist and I am 99% sure i've overlooked something simple...
A fridge does not violate the 2nd law because a fridge is not a closed system. The fridge exchanges energy and heat with the surrounding environment. The reduction in entropy inside the fridge comes at a cost of an even greater increase in entropy in it's surrounding environment.
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"A fridge does not violate the 2nd law"
Yes - I know that and I never said it did - I was making the point about bald statements such as "but the end result is always that heat flows from hot to cold"
The point about the 2nd law is that the entropy of the whole universe increases so that the apparent reversal by heat pumping needs to be balanced by the increased entropy of the process driving the pumping - probably generating electricity
That you can't pass heat from the cooler to the hotter
Try it if you like but you far better notter
'Cause the cold in the cooler will get hotter as a ruler
'Cause the hotter body's heat will pass through the cooler
Oh, you can't pass heat from the cooler to the hotter
You can try it if you like but you far better notter
'Cause the cold in the cooler will get hotter as a ruler
That's the physical law
(c) Flanders, Swann & Newton
They have designed a technology which instead of bending microwaves or light can shield an object from heat - or concentrate heat upon it.
Hmm, surely you can achieve the same thing by placing a piece of card over a piece of glass you're focussing sunlight with to explode a ant?
Not that I ever indulged in such behaviours as a child.
But isn't this inside a *simulation* software package?
As El Reg readers know almost *anything* is possible when you start with the "right" assumptions.
So how do you *implement* this IRL?
File with the Hong Kong university students and the Graphene fuel cell "harvesting" energy from ambient heat.
*highly* suspicious.
Sounds like any serious space travel involves the success of Mitsubishi, Frigidaire, Hyundai, and a very, very powerful cable to tow the heat source, and to tow a HUGE amount of water.
But, once water is boiling in a towed vessel, how would such boiling be reduced in space? Towing heat balls and transferring the heat, hoping the temperature drops with each transfer? That would -- depending on the engine heat, life support heat, computing heat, human body heat, and space heat -- take a lot of thermal balls.
It seems that space travel will become a great deal longer with navigational waypoints for cold zones determining the flight path. But, if not enough touchable icy comets and dark sides of moons exist along the route, things till boil to a head.
Maybe multiple pulse rockets will be designed to fire, attain desired velocity to course, then jettisoned when the heat is too unsafe to tow or use. But, instead of merely abandoning the engine module or destructing it, it can shut down so that it can be used by a compatible ship taking the same shipping lane.
Come to think of it, engines could be staged at multiple direct path points and ships would just eject and thruster-park ditched engines, then coast to the next engine way point, then hitch a thrust ride off of it. Wash, rinse, repeat. But, any staged, hitched, and ditched engines would need computers and navigation systems, and may either be self-parked prior to first hitch, or carried in clusters by an initially-towing system.
Hot or Cold Pre-Staged Engines
What say ye? I'm not claiming it's novel, but I also cannot recall having read this idea elsewhere and "imprinted" with it.
Say, down-thumber,
Would you care to justify why you down-thumbed my comment? I was trying to seriously explore means of heat dissipation, but you got personal, or you clicked the wrong comment. So, how would YOU go about dissipating the mammoth amount of heat that would be generated, in the absence of water, wind, or a transference medium to do it in a fast manner safe for travel?
If you're going to do juvenile or vendetta drive-by-down-thumbs, then please supply a non-down-thumbable, rational explanation to EDUCATE an uninformed rationalization (not muses or jokes, but explorations). If by chance you hold 5 degrees and key positions, keep in mind that a down-thumb is silence, not convincing assistance. Or, you're being a bully. Either uprate or don't rate, but unless you've got a provable, real, meaningful reason to stab someone's comments, then go away. I don't stab people out of the blue like a drugged-up slasher on a train. I read comments, and those I like, I uprate. Those I cannot figure out, I move on. Everyone's got quirks, but scraping people's quirks causes stress.
The article, and the Beeb's coverage of the same story is similar, starts by explaining that heat transfer is conductive rather than radiative, but then goes on to suggest applications in spacecraft design, where (even the article points out) heat transfer *is* purely radiative.
What gives?
So it sounds like they are applying the techniques used in the other cloaking tests, in other words using different materials. Surely all they are doing is using low k material to shield insulate regions or providing solid High K Material for conducting heat-lanes to focus heat.. is there really any new science here?
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