Are refrigirators basically Maxwell's Demon?

[enderlord99]

I mean, they make one side (the inside) colder and the other side (the outside) hotter...

[Spojaz]

The end result is kind of the same, but the processes are very different.

Maxwell's demon works by finding the hot and the sold molecules and sorting them.

Refrigerators work by pressurizing the all molecules to make them all "act" hotter while sending them outside the casing, losing heat, then returning them to normal pressure on the inside which makes them colder then they were.

In the refrigerator the "hot" and "cold" molecules are the same ones on different parts of the cycle.

[Kato]

I mean, they make one side (the inside) colder and the other side (the outside) hotter...

I'm.... not sure how serious you are. I'll admit, cooling gadgets are still one of my favorite marvels of modern society, but no, a fridge is not Maxwell's demon. It doesn't sort fast and slow particles, it uses the fact that an expanding liquid or gas absorbs energy from its surroundings. I mean, it's still really cool, but it's not demonic.

[Knaight]

I'm.... not sure how serious you are. I'll admit, cooling gadgets are still one of my favorite marvels of modern society, but no, a fridge is not Maxwell's demon. It doesn't sort fast and slow particles, it uses the fact that an expanding liquid or gas absorbs energy from its surroundings. I mean, it's still really cool, but it's not demonic.

It also often takes advantage of how liquid-gas phase transitions generally involve a lot of heat being transferred, and a pressure drop can make a mostly liquid equilibrium a mostly gas equilibrium. How this is done varies, but throttle valves are pretty much the easy way to do it, provided you're under conditions where that's an option.

[factotum]

Also, fridges don't actually break the laws of thermodynamics as Maxwell's Demon is supposed to...

[DigoDragon]

I believe an important part of the thought experiment is that the two defined areas in contact need to be isolated from the rest of the universe. The inside of the fridge versus "outside" doesn't seem to work for the experiment if the outside is "the universe minus the inside of the fridge".

[Ravens_cry]

I read that one possible refutation for Maxwell's Demon is that it needs to be able to identify if a molecule is moving fast or slow, and that takes energy.
Needless to say though, no, a fridge is not Maxwell's Demon.

[Brother Oni]

Refrigerators also don't get to wear a snazzy cloak like a Maxwell's Demon does (https://books.google.co.uk/books?id=fqyWBAAAQBAJ&pg=PA121&lpg=PA121&dq=maxwell+demon+oh+my+goddess&source=bl&ots=-BYFLdkEf6&sig=Y6LGR__PUiqE4BRtk-7He8x-IJ8&hl=en&sa=X&ved=0CB4Q6AEwAGoVChMI5Z_1s62iyAIVw7oaCh3m4gGH#v=on epage&q=maxwell%20demon%20oh%20my%20goddess&f=false).

Well, I suppose you could dress your 'fridge up with a cloak, but it would have to be a really slow (or drunk) Saturday night.

[Jay R]

No. Maxwell's demon would be much cheaper.

[Dodom]

@Oni: Your link drives into a paywall! D:

[Brother Oni]

@Oni: Your link drives into a paywall! D:

I see a page from the Oh My Goddess manga where they explain what a Maxwell's Demon does. It's probably randomised as to which page you see.

[Dodom]

I tried again and now it worked. First time around it said I had exceeded the number of pages I had paid to view. Weird!

[Sith_Happens]

I see a page from the Oh My Goddess manga where they explain what a Maxwell's Demon does. It's probably randomised as to which page you see.

...Right after mentioning the existence of Laplace's Demons.

I have to read this manga now.

[Knaight]

No. Maxwell's demon would be much cheaper.

A lot of refrigeration honestly isn't that expensive, particularly relatively high temperature cooling in industrial applications where energy is cheap. Things like low temperature liquid helium run up ludicrous costs, but industrial freezers are not that big of a deal.

[Brother Oni]

...Right after mentioning the existence of Laplace's Demons.

I have to read this manga now.

It's a very cute, gentle manga, where a college student (Keiichi) is granted a wish by one of the Norns. Since he can't get a girlfriend, he thinks its a joke by his dormmates, so he wishes that a girl like her could stay with him forever.

Wish granted.

After getting kicked out of the male only dorms, Keiichi and the Norn end up living at a temple together. The Norn turns out to be Belldandy (a Japanese interpretation of Verdandi), who is one of the three systems operators for the Yggdrasil computer system which runs the universe. Hijinks occur, with Belldandy's sisters turning up (Urd and Skuld, unsurprisingly).

The writer is a big motor vehicle fan and there are some very detailed diagrams and technical talk (Keiichi is part of the auto club).
http://2.p.mpcdn.net/357/8097/2.jpg

[tomandtish]

I'm just happy to know I'm not the only one who can't spell refirgara.. Refrigora... Fridge. :smallwink:

[Ravens_cry]

I'm just happy to know I'm not the only one who can't spell refirgara.. Refrigora... Fridge. :smallwink:
Wasn't it nice when it was called an 'ice box'?:smalltongue:

[Kato]

Wasn't it nice when it was called an 'ice box'?:smalltongue:

Well, "we" (i.e. Germans) call it what boils down to "cooling cupboard". Also, way easier to remember. Maybe you could adapt that. I guess Freezer works, too. Or Cooler.

[enderlord99]

I guess Freezer works, too.

No, freezers are even colder than fridges, and store entirely different things.

[Douglas]

I guess Freezer works, too. Or Cooler.
A refrigerator cools thing to somewhere between room temperature and the freezing point of water. A freezer cools things to below the freezing point of water. Both are often sold together, even as parts of the same machine, but they are still physically separated and referred to separately.

A cooler, meanwhile, is a man-portable container that doesn't have any cooling ability of its own but insulates from the surroundings very well so that cold things inside it will remain cold for a long time even while being transported elsewhere. Coolers often have ice packs put in them to make the cold last even longer.

It seems the obvious and understandable names were already taken, so whoever named the refrigerator, in grand English tradition, bastardized something from another language. Or maybe "refrigerator" came first and whoever it was just wanted something that sounded fancier.

[factotum]

It seems the obvious and understandable names were already taken, so whoever named the refrigerator, in grand English tradition, bastardized something from another language. Or maybe "refrigerator" came first and whoever it was just wanted something that sounded fancier.

The word "refrigerate" has been around since the 17th century--it's derived from the Latin "refrigeratus". One assumes that they just modified the word when mechanical cooling devices were invented in the 19th century.

[Jay R]

The serious answer is this:

Maxwell's demon uses the ability to separate cold molecules form hot ones, and to treat them differently.

Refrigeration uses a substance that absorbs and generates energy when compressed and expanded. No choosing of individual molecules is involved.

They are completely different processes, even if they create the same result.

[Lethologica]

The serious answer is this:

Maxwell's demon uses the ability to separate cold molecules form hot ones, and to treat them differently.

Refrigeration uses a substance that absorbs and generates energy when compressed and expanded. No choosing of individual molecules is involved.

They are completely different processes, even if they create the same result.
Moreover, they don't really create the same result, because Maxwell's demon operates on a closed system, and the only way we can compare the result of refrigeration to Maxwell's demon is by allowing it to be an open system.