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Researchers Pave Way For Compressor-Free Refrigeration
Hugh Pickens brings news that scientists from Penn State have developed a new method for heat-transfer that may replace the common compressor-based system used in household appliances. Quoting:
"Zhang's approach uses the change from disorganized to organized that occurs in some polarpolymers when placed in an electric field. The natural state of these materials is disorganized with the various molecules randomly positioned. When electricity is applied, the molecules become highly ordered and the material gives off heat and becomes colder. When the electricity is turned off, the material reverts to its disordered state and absorbs heat. The researchers report a change in temperature for the material of about 22.6 degrees Fahrenheit... Repeated randomizing and ordering of the material combined with an appropriate heat exchanger could provide a wide range of heating and cooling temperatures."
a "reverse" microwave?
What?
Unless this is more efficient than at least Peltier it won't become commercially viable.
Engineering is the art of compromise.
I'll say, that's an interesting use of entropy.
Man o man, how many times I've thought to myself "How can I get rid the compressor that powers my refrigerator?" Oh technology, what can't you do?
Mod me down, my New Earth Global Warmingist friends!
wasn't there a compressionless sound wave-based cooling developed a few years back? i remember ben or jerry from ben-and-jerry's championing the efforts.
'cool'
Even if you're on the right track, you'll get run over if you just sit there. - Will Rogers
Congratulations on not even reading the whole fucking summary.
Perhaps they can work in series to achieve greater temperature differences.
Engineering is the art of compromise.
So, will this pave the way for a new style of super-cooling for the home computer overclocking enthusiast? ...
... cuz if not, I'm not really interested.
Wait, the fridge keeps my red-bull cold...
Hmm... I expect some readers to ignore the article and take the summary for granted, but did you even read the summary in total? "Repeated randomizing and ordering of the material combined with an appropriate heat exchanger could provide a wide range of heating and cooling temperatures." They will easily be able to get to normal refridgeration temperatures. Whether they can do this more efficiently than current technologies is another question entirely. It would have a great environmental impact if they could, as I assume this would also affect AC units and other temp-control devices in controlled environments within buildings.
How is this different from a Peltier cooler?
-R
This could feasibly be used to make a practical air conditioner by having a segmented disk shape block that allows air to pass through.
Outside air would pass through one half of the disk that is currently energised (the electric field orders the polymer and thus releases heat).
The inside air would pass through the other half that is currently not energised (the relaxation of the electric field allows the material to absorb heat).
The disk rotates with segments shifting between the outside / inside halves, the electric field is applied by a simple electric comutation.
This is not a true "no moving parts" system but it has the potential to be an order of magnitude quieter than the current air conditioning units.
ZombieEngineer
These polarpolymers include poly(vinylidene fluoride-trifluoroethylene) and poly(vinylidene fluoride-trifluoroethylene)-chlorofluoroethylene, ...
I'd like one of those poly-pola-try-viyl, er, I mean fluoro-frikkin-flora,.....
Ah, screw it. Gimme a fridge with a compressor.
Have gnu, will travel.
Cool.
Fool me once, shame on you. Fool me twice, watch it -- I'm huge!
It really doesn't matter so long as there is a Delta. It sounds like this can absorb and release heat as fast as an electrical switch can be flipped and mankind has made some pretty snappy switches that could repeat REALLY fast.
The real question is how much power is lost. Peltier coolers for instance are horrendously inefficient. If this isn't more efficient and/or cheaper than compressor technology it will never happen. Since compressor technology isn't cheap to produce the only thing that will likely stand in the way of cheapness is greed on the part of the patent-holder. We shall see.
Or Adsorption! Those fridges are very common where silent operation is needed: hotel mini-bars, offices. They're just not efficient.
The article is useless without mentioning efficiency. Inefficient alternatives are nothing new.
Being solid-state, one can hope this tech is silent. The buzz of our fridge-freezer is a pain.
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It is anti vaporware: it is refrigeration without vapors!! No more e-vapor-ators!
Prediction for end of Universe #42: Fencepost error in Quantum_bogosort.cpp
The compressor is the noisy part of a refrigerator, right? If you could make a refrigerator without one you'd have market differentiation over a desirable feature (quietness). Problem being, the heat differential is not great enough to work for the freezer, so if that's the best that's possible then your fridge would still have to have a compressor.
A compressor on a refrigerator lasts a very long time too, 20 to 30 years or more. One of the most reliable things out there. The biggest problem with refrigerators is the hinges and door seals wearing out.
We are Dead Stars looking back Up at the Sky
I am not a physicist, so feel free to flame me if my question is stupid. But the article mentions a design concept that would hook multiple devices up in a sequence or series, in order to continuously move a temperature in either direction. This concept would make sense if the principle of the phenomenon is based upon a relative temperature range, instead of an absolute range. But if that was true, that this phenomenon could alter an oven at 330 up to 350, or a refrigerator at 50 down to 30 freezing, and I can't imagine it being efficient without it also being magic. So, is it based upon a relative range of temperature, or an absolute one?
If your current fridge is too loud, then I suggest shopping for a new one. Many of the newer units feature far quieter compressors.
While you're at it, I'd suggest looking for an energy star one.
I don't read AC A human right
There, fixed it for you.
"To hope's end I rode and to heart's breaking: Now for wrath, now for ruin and a red nightfall!"
re freezer: You are forgetting something here. The inside of the fridge/freezer combo is a closed circuit (air-wise and refrigerant-wise). When you take a new freezer and it starts to cool, it's many passes of the air inside through the evaporator before it comes anywhere near freezing. That and the fact that there is still "heat" to be absorbed well below the freezing point (heat pumps anyone?).
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"...change from disorganized to organized..."
This sounds like it's forgetting some important law of physics, like, say, the second law of thermodynamics that states that the entropy of all real systems always increases.
Did you miss the bit where they apply an electric field?
...the second law of thermodynamics that states that the entropy of all isolated systems always increases.
There. Fix'd it for you.
When external energy is applied to the system (like, say, electricity), then the system isn't isolated.
The entropy of a closed system always increases. In this case, that includes where the electricity is coming from.
But do we really want to invest in a technology that decreases the entropy of the only Universe we have to live in?
Your current refrigerator has compressible refrigerant in it.
Which will destroy the world if it somehow leaks out.
And YOU will be responsible.
Wow, dumb much?
Clearly the stainless steel fork on the table next to me is a figment of my imagination, since the iron ore it was made from certainly had more entropy...
You can freeze and melt water quite a few times before it wears out.
Engineering is the art of compromise.
It sound like they have essentially developed a solid refrigerant. That has got to be far less useful than a liquid refrigerant that can me moved around to where it is needed. Not to mention since there is no phase change involved you need a buttload more of this fancy polymer to get the same heat capacity.
Nah. This will never be economically competitive.
I could be wrong, but it sounds to me that without the compressor machinery, this could enable smaller, quieter cooling units and lead to products like battery-powered thermoses or air-conditioned clothing. Do any engineers have a take on this?
He who lights his taper at mine, receives light without darkening me.
TFA is written very poorly and describes a phenomena involving polymers that is already widely known. There are many examples. Here is one you can try using something far less exotic than the polymers mentioned in the article.
For this example, take a rubber band. Stretch it out. Touch the stretched rubber band to your lips. It will feel warm. Hold it in the stretched position for a few seconds to let it cool down to room temperature. Now let the rubber band relax, and once again touch it to your lips. You should now notice that it will feel cool.
The above process uses exactly the same principles described in TFA. Stretching the rubber band causes reduction of disorder by aligning the polymer chains. It also warms the rubber band because of the work applied. As you hold the rubber band in the stretched state it will cool to room temperature releasing some of the energy needed to heat it. This is equivalent to the step where the electrical field is applied.
Now release the rubber band. The polymer chains now revert back to a disordered state, cooling the rubber. Since the rubber band started in a stretched room temperature state the relaxed rubber band will now be below room temperature. this is equivalent to turning off the electric field as mentioned in the article.
Voila. This is a wonderful new refrigeration system that will replace all existing known cooling systems. NOT.
There are so many issues with practical application of this it is not funny. If these issues didn't exist we would have been using rubber band refrigerators for many decades already.
Also, please note that from a thermodynamics point of view this is essentially how a conventional refrigeration system works (albeit fat far more efficiently).
By that logic, my food should've gone bad days ago. Maybe even earlier!
"It sounds like this can absorb and release heat as fast"
So do you think this gives off EM radiation as an electric field is applied or that it just heats up rapidly as it becomes ordered so that a heatsink can take the heat away (thus "gives off heat" as per the article), and removal of the electric field will then cause it to return to a colder temperature.
Since they suggest heat exchangers I going to guess that it warms with an electric field and cools without rather than gives of EM.
An EM device would be cool (pun intended) because you could place a grid of the material in relation to a grid of reflectors that forced the EM to a black panel behind which would be connected to a heat sink and physically insulated from the rest of the fridge and you'd be totally solid state.
Oh, oh, oh! I have an idea. Let's combine this idea with a stirling engine and see what kind of synergies come out.
Polymer on each end of the engine, alternating current synchronized with the displacer, etc. etc. etc.
Whaddya think?
OK, then you and I can probably agree that it is at least ambiguous. And you will also agree that heat transfers are regularly misunderstood.
When the charge is applied, the polymer becomes warm. If it is warmer than its surroundings, it will subsequently cool to the temperature of its surroundings.
If that is what the writer meant, then he did not make his point very well. My reading of that statement indicated to me that applying the charge would make the temperature of the item drop as well as making it give out heat: clearly impossible. In order to give out heat, it must first become hotter.
I imagine that the science-literate person wrote a clear and precise description, which a later reviser shortened into the mess we read.
Prediction for end of Universe #42: Fencepost error in Quantum_bogosort.cpp
More then 100% efficiency? This will make millions.
How many more years will slashdot have an off-by-one error on your Score in your profile?
Going by the rough description in TFA, it sounds like electricity's effect on the ferropolymer causes its bonds to strengthen, or perhaps to magnetically align, increasing rigidity, reducing the material's potential for containing kinetic energy.
If the material's new state caps the amount of kinetic energy it can store, it has to move on - first law of thermodynamics and all.
This may be the next interesting bit in applying their discovery - finding a compatible heat conductor, and also learning the optimal frequency, voltage, current etc. at which to apply voltage.
O lord, bless this thy holy hand grenade, that with it thou mayest blow thine enemies to tiny bits, in thy mercy.
Coefficient of performance. You can move more heat-"energy" than the energy you put in, but the very low temperature difference makes it low quality heat. Heat pumps become more effective the closer together the temperatures are. Sadly, heat-engines become less effective the closer the temperatures are.
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Is it more or less effective than
MOD -1 FLAMEBAIT?
Inquiring Slashdotters want to know.
On a serious note, a 23 degree F differential is nice for things like keeping my drink at 55F in a 75F office, cooling a house from 90F to 75F, and it might aid compressor-based systems, but it won't work well alone in those parts of the world where daytime highs get much above 100F or in cars that get baked to 130F in the hot summer sun. Still, assuming my car battery is fully charged, being able to partially turn on my all-electric no-compressor car air conditioning 10 minutes before I get in can turn 130F to 110F or perhaps even down to 20F below the outside-air temperature, which is a big help. Also, having a self-chilling seat and steering wheel to keep them below scalding would be a godsend on those hot summer days.
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
...weird, you'd only expect the weatherman to do that (or the yellow press trying to inflate a figure).
Tribute to Lord Kelvin, anyone?
Reminds me of something I learned about low-temp cryocooling way back in P.Chem:
Adiabatic Demagnetization.
sigfault (core dumped)
I'm not sure how close they come to reverse Carnot in a modern "fridge", but they are very durable. It seems like we had two refridgerators the whole time I was growing up, and the only reason we got the 2nd one was because we were in a different house. It's not exactly like they were being fixed all the time either. In fact, aside from the fact that the fridge we had when I was a kid required manual defrost, I don't think they ever required maintenance. The HVAC unit in my old condo had to be pulled. This was in 2006. When the tech opened it up, we discovered it was build in 1979. These units are essentially refrigerators too, with compressors. Now, that was a good old USA unit, with a steel housing and everything. I'm not sure if the cheapo plastic jobs they installed will hold up as well, but that's an implementation issue, not a problem inherent with the underlying tech.
The point is, can this new technology be as efficient as a compressor, as cheap as a compressor and as DURABLE as a compressor?
That said, perhaps it will find applications outside of keeping your OJ cool and your brow dry. If it does, great; but the current tech is pretty good. I wish they were silent, but even at that, a modern fridge is pretty quiet too.
For all intensive purposes, "whom" is no longer a word. That begs the question, "who cares"?
It sounds like this can absorb and release heat as fast as an electrical switch can be flipped and mankind has made some pretty snappy switches that could repeat REALLY fast.
Most people don't want the heat back in the same place it was absorbed. A fast switch isn't needed. A fast transport of the device from the hot side heatsink back to the cold side heatsink is needed.
Maybe if this was built into an electric motor, we could have one side hot and one side cold as they spin from side to side. Hmm Maybe a fan that blows hot air through the left side and cold through the right side. ;-) Just duct the hot and cold where you want them.
The truth shall set you free!
Please. You can do this with a rubber band. Stretch it and it becomes more "ordered" and hot. Release it and it gets cold. (Use your lips as a thermometer.) Not that *anything* like this makes a practical heat pump. For efficiency you need a *phase change*, and this principle just does not supply that.
Researchers Pave Way For Compressor-Free Refrigeration
Actually, we've had usable refrigeration without a compressor for most of the last century. It's the gas absorption refrigerator and they are in RVs, dorm rooms and offices all over the world. In fact most small (as opposed to tiny) fridges don't have a compressor.
If intelligent life is too complex to evolve on its own, who designed God?
Yes, you are right. There are many ways to induce first order phase transitions in various system, leading to the release or take up of heat.
The special thing about the device in the article is that this phase transition is induced by an electric field, the so called electrocaloric effect. Therefore no movable parts in the system are required. Previously only small temperature differences have been demonstrated in metal oxides (click ...
(reposting of previously mangled up comment)
Yes, you are right. There are many ways to induce first order phase transitions in various system, leading to the release or take up of heat.
The special thing about the device in the article is that this phase transition is induced by an electric field, the so called electrocaloric effect. Therefore no movable parts in the system are required. Previously only small temperature differences have been demonstrated in metal oxides (smaller than 10K). By using ferroelectric/antiferroelectric polymers they are apparently able to increase the temperature difference to above 10K, which is a very significant increase.
That said, this of course typical university hype science and practial application faces many engineering and also intrinsic scientific problems. First of all they have not measured the temperature difference, but deduced it indirectly from maxwell relations. In a realistic set up the temperature difference will be lower.
A second problem is intrinsic to the material and has been conveniently neglected: Since the principle relies on a solid insulator the heat conductivitiy is extremely low. (No convection, no electronic heat conduction). This means that you are able to create a temperature gradient, but are not able to transfer a lot of heat, thereby severely limiting the cooling ability.
A third problem is that this effect only works in a very limited temperature range (above 70ÂC). A fourth problem is hysteretic heating due to ferroelectricity...
Link to the original article: click
It sounds like this can absorb and release heat as fast as an electrical switch can be flipped and mankind has made some pretty snappy switches that could repeat REALLY fast.
Yeah, great. Now you just have to put in the whole thermodynamic cycle:
1. Switch on
2. Establish thermal contact to hot side, wait for heat to leak.
3. Cut thermal contact to hot side.
4. Switch off.
5. Establish thermal contact to cold side, wait for "cold" to leak.
6. Cut thermal contact to cold side.
7. GOTO 1.
8. ????
9. Profit!!
The switching is really the easy thing.
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A third problem is that this effect only works in a very limited temperature range (above 70ÃC). A fourth problem is hysteretic heating due to ferroelectricity...
I wouldn't be so worried by that. If you look at fig. 1 you'll see that the hysteresis isn't so horrible, and that the electrocaloric effect is roughly constant in the range 70-100C. Of course that's the wrong temperature range, but this is very new, and it's quite likely that changing the composition will give materials with the same effect around room temperature.
I very much agree with all the rest you said, though.
Any sufficiently advanced libertarian utopia is indistinguishable from government.
Then we have a whole new Thermocouple technology the question is would it be any more efficient than existing thermocouples.
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There seems to be a lot of misunderstanding about how a fridge based on these materials would work. Compare it with existing refrigeration systems: -
1) Compressor based systems. Here a working fluid (freon, etc) is pumped around a sealed circuit. At one point in this circuit it undergoes a state change (i.e. is compressed) and releases heat to the environment (via the radiator on the back of your fridge). At another point in the circuit it undergoes a different state change (i.e. pressure drop) and it's temperature drops as a result (taking in heat from the environment). Note that this is a working fluid we are talking about here.
2) Thermoelectic devices. These rely on devices with the property that when a voltage is applied to them a temperature gradient is created directly. Quite elegant, but not very efficient with currently available materials (although there have been recent developments in this area which may make them as efficient as compressor based systems in the medium term).
3) Polarpolymer based devices. In this case the working material is a solid with the property that when you apply a voltage it undergoes a state change causing its temperature to rise by 22degrees. The heat released would then have to be removed to the environment (for example by blowing air over it and venting this to the environment). When the voltage is subsequently removed, the material returns to its original state (22 degrees F colder). You would then need to circulate air from the inside of your refrigerator over this material. Some of the heat in the (inside) air would transfer to this material, warming it up. A drop of more than 22 deg could be created by daisy-chaining several devices together in series to create an arbitrarily large drop.
So a polarpolymer based refrigerator would probably require a quite different design to a traditional fridge because the working material is a solid rather than a fluid, and it does not directly create a temperature gradient across the material.
It probably wouldn't be suitable for small scale applications such as gloves, or for cooling clothing - unless your application just wants a one-time temperature rise/drop and the reverse step takes place away from the wearer of the clothing.
sounds like the Szilard/Einstein refrigerator of the 20s, which used a ferrous-based refrigerant moved with magnets.
if this is supposed to be a new economy, how come they still want my old fashioned money?
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When you're storing wine for a long time sediment settles out and a compressor will stir it up. Not good for the taste.
So now you have a material that can cool on command by an electrical signal. Nice.
So now you make it touch your fridge, and tell it to go to the "cool state". Next it absorbs heat (that leaked through the walls of the fridge), and you need to expell that heat. So now you turn it to the "warm" state, Now it's heating your fridge? No you need to make it insulated from the fridge, and thermally connected to the outside to pump the heat out. How are you going to do that?
The easiest way would be to have two of those electro-thermal-active-plastics built as a heat exchanger. One of them (the one in the "hot" state) circulates an appropriate fluid with the heat exchanger on the back. The other circulates the fluid with the heat exchanger inside the fridge.
So, how about we get rid of those nasty ozone-layer-affecting CFKs? Nice try, but no go! These ARE CFKs we're talking about. Maybe easier to contain than CFK gasses, but CFKs notheless.
Next, when your element is exchanging heat with the fridge, and it has come to an equilibirium.... Then you change it to the "warm" state. Now it becomes 12.5 degrees centigrade warmer! So my fridge is 4 degrees, and the element becomes 16.5 But in the summer my home is warmer than that (actually in the winter as well!). It has to become warmer than the environment to expell heat. So we're going to need a two-step heatpump.
So instead of a fridge with one pump, two heat exchangers, and a replacement for the CFKs for the old days, we might go to a frige with three pumps, two valves, and four CFK -containing active essential elements!
I predict that everyone will have one of these in their house in 5 years! Not!
Yeah, great. Now you just have to put in the whole thermodynamic cycle:
1. Switch on
2. Establish thermal contact to hot side, wait for heat to leak.
3. Cut thermal contact to hot side.
4. Switch off.
5. Establish thermal contact to cold side, wait for "cold" to leak.
6. Cut thermal contact to cold side.
7. GOTO 1.
8. ????
9. Profit!!
I like how the last 2 steps are unreachable...are you trying to say something about the viability of this technology? ;-)
Dan Aris
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This is way over the top. Even assuming this was the refidgeration assembly in your refridgerator and HVAC both, and it was made 100% of PVC, it would still have way less PVC than in other parts of your house. All the wiring in your house is PVC. It makes up the screen of your television. It makes up the casing of your laptop, your CD / DVD player, and pretty much every other piece of electronics in your house. All that vinyl siding on your house, PVC.
Sounds like you are living in a death trap! Get out while you can!
"These polarpolymers include poly(vinylidene fluoride-trifluoroethylene) and poly(vinylidene fluoride-trifluoroethylene)-chlorofluoroethylene, however there are other polarpolymers that exhibit the same effect."
It doesn't say what the "others" are, but perhaps there's something that can be used that would be more tolerant of high heat (or less toxic). Alternately, perhaps it could be used in a heatsink type scenario wherein the sink is cooled as it absorbs heat, but doesn't become superheated itself.
Sounds far too complex to be cheap.
Position the 'device' at the top of the fridge in an insulated tube. Put a heat sink directly above the 'device'. The heat will rise, heat the heat sink, and be removed by airflow outside the fridge.
Simple, cheap, and since transistor switching is REALLY fast, it would put the practical limitation on the speed of the heat exchange process.
I think that the idea that this requires no moving parts is something of a red herring. Yes it requires no moving parts to accomplish the phase transition, however there is still the issue of heat removal from the polymer. Some sort of heat exchanger will be needed, presumably convectively cooled by something, and of course there is the issue of how do you prevent the polymer from heating whatever you are trying to cool while the electric field is applied.
I think that there are some practical applications to this, particularly where you would want direct contact between the coolant and whatever is being cooled. The solid coolant may provide advantages in terms of not requiring a downstream separation process.
But this isn't going to replace conventional compressor-evaporator-condenser systems.
I never could find the compressor in my gas refrigerator.
Was it stolen?
"We still have the same appliances we did 50 years ago, and that is not likely to change in the next 100 years."
Yes, and everybody had microwaves in the 1950s. Oh, wait...
Just "gittin-r-done," day after day.
cue techies around the world trying to create a rubber band refrigerator. Heh, sounds like fun.
They propose to combine it with peltier elements to construct a heat pump. As always the term 'refridgerator' is misleading.
There are a lot of issues that need to be known before this could be considered useful technology.
1. Price. Is the initial outlay too expensive?
2. Lifetime. Will it last as long as a current unit.
3. Efficiency. Does it require more or less power than current units.
4. Cooling. Can it freeze ice cubes in 80 degree weather?
5. Size. Will it fit into the same space?
All the article says it that it is quieter. People live with a noisy AC turned on for many hours a day, and a fridge is much quieter than that, so noise isn't that much of a factor.
Who would win this election: Andrew Weiner vs Andrew Weiner's weiner.
wasn't there a compressionless sound wave-based cooling developed a few years back?
It's called "thermoacoustics". It involves "motors" that turn temperature gradients into sound and "refrigerators" that use sound to pump heat across temperature gradients.
It's been around for perhaps a century, and is in its third generation of development. (It's a prime example of patents retarding technological development, as the current generation of development started after the patents on the second generation expired.)
This generation is on a solid theoretical footing, with mathematical models close enough to the real behavior to perform engineering and computer simulations that can run on your laptop. Lots of cute gadgets are coming out of it.
Example: A two-story hunk of plumbing with a gas burner. Haul it to an oil field in some out-of-the-way location where the gas is being flared off because it's too expensive to liquefy it for shipping. Hook the well gas to the input pipe, the output pipe to a storage tank, and light the burner. It sits there humming away internally, burning part of the gas and liquefying the rest.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way