Talk:Magnetic refrigeration

Citations, Refs., Notes:

Also used for heating

"Michigan startup’s magnetic tech aims to transform efficient heating, cooking, and more" [1] The company is HeatX (I have no affiliation!)

Chipotle (talk) 19:56, 23 February 2022 (UTC)[reply]

Comment

Why is this useful for spaceships? Who said this about spaceships?

According to a recent article From Anders Smith,^[1] Warburg did not observe the magnetocaloric effect, the discovery of the effect should instead be attributed to P. Weiss and A. Piccard in 1917.

Warburg did not discover the magnetocaloric effect, but rather he measured heating from dissipation in iron rods. This was an indication of magnetic hysteresis. — Preceding unsigned comment added by 192.55.54.44 (talk) 21:55, 7 July 2017 (UTC)[reply]

References

^ Smith, Anders (2013). "Who discovered the magnetocaloric effect?". The European Physical Journal H. 38 (4): 507-517. doi:http://dx.doi.org/10.1140/epjh/e2013-40001-9. {{cite journal}}: |access-date= requires |url= (help); Check |doi= value (help); External link in |doi= (help); Unknown parameter |month= ignored (help)

Recent announcements

Dr Karl G Sandeman of Imperial College London references several articles between 2006 & 2009.

Sujoy Roy, a physicist at the Lawrence Berkeley National Laboratory in California search for an alloy that exhibits the effect at room temperature is reported at Phisics.org. Timpo (talk) 07:05, 7 July 2010 (UTC)[reply]

Professor Stadler at LSU announces new material (not disclosed) for room temperature refrigeration http://phys.org/news/2015-04-material-cooling-industry.html --Mike dill (talk) 02:00, 14 April 2015 (UTC)[reply]

COMMENT

I tried to reorganize these, but I'm really a noob at this, and the WP Ref standards seem to be in flux now Poppafuze 22:07, 16 October 2006 (UTC)[reply]

I don't know how to add cites. But this is a good link: http://www.nist.gov/public_affairs/releases/magrefrig.htm —Preceding unsigned comment added by 68.8.0.127 (talk) 10:08, 22 July 2009 (UTC)[reply]

I had the same problem! The solution is at Template:Cite web I prefer the vertical layout model! Just click one or the other of these> Timpo (talk) 07:05, 7 July 2010 (UTC)[reply]

Ferrofluid cooling

Lets say we have a tube filled with ferrofluid, standing vertical. We apply a strong magnetic field to the lower part of the tube, causing it to heat up. We lead that heat off through a heatsink. - Shouldn't the upper part of the tube of ferrofluid now begin to cool down simply because cold stuff is denser than hot? --Ceriel Nosforit 11:42, 6 July 2007 (UTC)[reply]

No, nevermind. It was a brain-fart.--Ceriel Nosforit 11:48, 6 July 2007 (UTC)[reply]

General Comments

This subject is important enough that it should be clear to the general reader; I think it is fair to say any article with the word adiabatic is not meeting tht criterion. Since it is a great article, I'm reluctant to jumpin...Cinnamon colbert (talk) 02:46, 28 November 2007 (UTC)[reply]

Heat Capacity

Cool stuff.

"The stronger the magnetic field, the more aligned the dipoles are, and this corresponds to lower entropy and heat capacity because the material has (effectively) lost some of its internal degrees of freedom."

What does heat capacity have to do with PV=nRT, and isn't entropy more of a metaphysical concept? I always hated entropy... abstract, metaphysical, and I don't ever recall using entropy in any equations dealing with thermodynamics.98.165.6.225 (talk) 10:06, 22 August 2008 (UTC)[reply]

George Pickett

Suggest that someone adds some reference to Georget Pickett of Lancaster University to this page. —Preceding unsigned comment added by 82.20.226.120 (talk) 00:20, 13 September 2009 (UTC)[reply]

How long does this take?

Does anybody know about how long it would take to get a hypothetical refrigerant to household refrigerator temperature using this method?

Thanks, if an answer exists. —Preceding unsigned comment added by 98.169.1.50 (talk) 00:51, 6 October 2010 (UTC)[reply]

Second law violation?

Please excuse me, as I don't want to mix critical thinking together with original research, but doesn't the second law of thermodynamics state that heat cannot flow from a colder body to a warmer one? How is it possible to explain magnetic refrigeration in terms of energy without violating that very law (which of course if it did would also violate the first law....). Thank you for any answers, and yes I do think this is relevant for the article. --Nabo0o (talk) 20:38, 22 November 2010 (UTC)[reply]

Hello! Isn't this a little bit too important to just ignore? Are there any qualified scientists/amateurs here who can explain this? Thank you. --Nabo0o (talk) 14:49, 27 December 2010 (UTC)[reply]

As far as I can tell, adiabatic demagnetization functions here the way adiabatic expansion functions in the average compressor refrigerator. Darryl from Mars (talk) 00:52, 4 July 2012 (UTC)[reply]

Oh gee, I guess I found out the answer to the controversy section. He was probably right, and it would work like heat pumps, only at an efficiency several magnitudes higher than convectional ones. We can't have that can we? --Nabo0o (talk) 16:07, 27 December 2010 (UTC)[reply]

Is anyone still confused about this? I am a complete layman in this area, but it makes sense to me. The natural non-magnetized state of the materiel has a higher heat capacity than the more ordered magnetized state. Have you seen those bags of saltwater that crystallize when the metal disk is clicked? Supersaturated solution crystallisation-type hand warmers are like this magnetization process. The liquid form of the hand warmer is like the demagnetized form of the material, and the crystal form is like the magnetized form. The atoms in the demagnetized form are able to hold more heat, because they can move independently of one another. But in the magnetized form, they are forced to move together, so the heat energy that they already contain is more easily transferred to the surroundings. When magnetized, the material lets go of its heat energy, but when demagnetized it is able to absorb more heat energy. The thermodynamic laws are not violated, because the total energy is conserved - it is simply transformed from one form to another (ordered atoms and excess heat to disordered atoms and heat-sinkability). But like I said, I', just a a layman and have little to no training in this field of physics. --Scorde (talk) 22:42, 9 March 2014 (UTC)[reply]

If anyone else is still confused, I would suggest asking for help on the Physics Stack Exchange, or some other physics forum, rather than Wikipedia. Magnetic refrigeration is a real, observed effect! (although at the moment it is used mostly in research for very cold temperatures). DigitalHamster (talk) 14:35, 7 June 2023 (UTC)[reply]

way to jargonistic for encylopedia

respectfully, as someone with a phd in mol biology, who knows how hard it is to simplify..this article has way to much complex jargon. How about something simple: For certain materials, changing the magnetic field near the material (eg, moving a magnet closer or furhter away) will cause the material to change temperature; htis phenomenon is commonly called the magnetocaloric effect. In most cases, as the magnetic field is decreased (less magnetism) the temperature of the material will drop.

or something like that. eschew words like adiabitic, entropy, etc etc. I mean, jehosaphat, don't any of you people understand the level needed for an encylcopedia ???? — Preceding unsigned comment added by 50.195.10.169 (talk) 21:34, 18 June 2013 (UTC)[reply]

COMMENT

This is perhaps something to be submitted elsewhere, but I want to get the idea "out there". First off, could there be some sort of "Ideas to improve humanity" section in Wiki articles (like in the talk page), in which people could submit ideas on ways to use the information in the article to "decrease world-suck"?

Secondly:

Bicycle-powered refrigeration for the outback - could this technology be combined with clockwork-driven, bicycle-powered potential energy battery to provide refrigeration in areas where electricity is relatively inaccessible or unreliable?

The clockwork portion would use spring thermometer (or somesuch) technology to trigger the use of the potential energy (much like a wind-up pocket-watch) which would be used to rotate the refrigerating material as needed. There would be a detachable bicycle drive which could be used to "recharge" the potential energy battery. The battery could be anything from a spring, to a counterweight, to whatever works better than those things.

Question for engineers who are familiar with the amount of energy this type of refrigeration requires:

Once this technology is usable in kitchen appliances, would this be feasible?

Scorde (talk) 22:54, 9 March 2014 (UTC)[reply]

Intro may make extravagant claims

The Intro presently says:

Compared to traditional gas-compression refrigeration, magnetic refrigeration is safer, quieter, more compact, has a higher cooling efficiency,...

Is all this really in sources 1-3? These claims are not supported by the following article. What are the safety risks of gas-compression refrigeration, unless it uses ammonia in large commercial systems, which anyway are not relevant here? Which existing magnetic refrigerators that can directly compete with existing gas-compression refrigerators are quieter, more compact, more efficient? Does this statement compare apples with oranges, in terms of existing implementations versus physical principles? Layzeeboi (talk) 08:07, 26 March 2016 (UTC)[reply]

Gizmag.com - Magnetic fridge eliminates gases, drastically reduces energy use

http://www.gizmag.com/cooltech-commercial-magnetic-cooling/43874/

quote from article: "Cooltech's first commercial system, the MRS400, boasts 400 W of cooling power, keeping the internal temperature between 35.6° F and 41° F (2° C and 5° C), which is within the recommended levels for safe food storage."

Looks like a company called cooltech France has released a commercial magnetic refrigeration system to the domestic market, the MRS400. http://www.cooltech-applications.com/magnetic-refrigeration-system.html — Preceding unsigned comment added by 110.148.166.13 (talk) 14:02, 10 July 2016 (UTC)[reply]

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I think the MCE.gif is incorrect. Specifically, the pictures with red and blue background for magnetic refrigeration. In adiabatic process, entropy should be the same. So, the amount of disorder should be the same. Then, the red picture should have disordered moments and the blue one should have aligned moments. For example, in an adiabatic demagnetization process, magnetic moments want to be disordered when magnetic field is decreased. But they can't, because they have to keep the same entropy. In order to keep the aligned state (same entropy), temperature has to decrease. — Preceding unsigned comment added by Yoshitokiwa (talk • contribs) 15:11, 20 June 2017 (UTC)[reply]

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Recent developments for quantum computing

In this article https://amp.tomshardware.com/news/permanent-magnetic-cooling-quantum-computers-tum,39586.html scientists create a magnetic refrigerator that uses permanent magnets, aiming to cool down quantum chips, planning to commercialise the invention. Blastofftek (talk) 17:09, 6 June 2019 (UTC)[reply]

[1] Smith, Anders (2013). "Who discovered the magnetocaloric effect?". The European Physical Journal H. 38 (4): 507-517. doi:http://dx.doi.org/10.1140/epjh/e2013-40001-9. {{cite journal}}: |access-date= requires |url= (help); Check |doi= value (help); External link in |doi= (help); Unknown parameter |month= ignored (help)

[1]