Topic: A refrigerator that cools using magnets

Just something I found.
http://www.denmark.dk/en/servicemenu/News/ScienceAndITNews/MagneticRefrigeratorNeedsNoElectricity.htm

More information at this article:
http://www.engineerlive.com/design-news/18623/magnetic-cooling-at-room-temperature.thtml

Not sure if it'll be that much better for the environment - obviously if they can demonstrate that is, that's great, though.

ATW:
Gadolinium is never found in nature as the free element, but is contained in many rare minerals such as monazite and bastnäsite. It occurs only in trace amounts in the mineral gadolinite, which was also named after Johan Gadolin. Today, it is prepared by ion exchange and solvent extraction techniques, or by the reduction of its anhydrous fluoride with metallic calcium.

Doesn't sound particularly cheap or environmentally friendly to me... but of course most refrigerators on the market now require lots of crap, too.

(Edited by reisio on 09-28-2007 00:34)

Ancient news - such things have been used by NASA for decades.

To realize how old the technology is, this was one of the Physics problems on a Test back in Highschool, to figure out with X volumn of the gas that is magnetically being influenced, how much cooling could be done in Y amount of time (basically, how energy efficient was it).

WebShaman | The keenest sorrow (and greatest truth) is to recognize ourselves as the sole cause of all our adversities.
- Sophocles

Electric cars are ancient, too.

What I was alluding to is that such refrigerators have been in use for decades now.

The problem is that building the things is pretty expensive, when compared to a normal household frig.

WebShaman | The keenest sorrow (and greatest truth) is to recognize ourselves as the sole cause of all our adversities.
- Sophocles

I suppose the real breakthrough here is that somebody (or bodies), somewhere, decided to invest huge sums of money in perfecting and/or domesticating the technology.

As with any 'green' technological progress, the cost of development and manufacture would hopefully be offset by the eventual savings in conserved energy and increased economy/efficiency. While the impact upon the environment is harder to put a real value on, it is presumably another reason for the ever increasing interest in such projects.

Of course, the outlay for such progress is rarely over-estimated, so it remains to be seen whether we really can save the world while saving a few pennies in the process.
_____

Sure, the concept is pretty old:, but real advances have only been made in fits and starts;

quote:

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The effect was discovered in pure iron in 1881 by E. Warburg. Originally, the cooling effect varied between 0.5 to 2 K/T.

Major advances first appeared in the late 1920s when cooling via adiabatic demagnetization was independently proposed by two scientists: Debye (1926) and Giauque (1927).

The process was demonstrated a few years later when Giauque and MacDougall in 1933 used it to reach a temperature of 0.25 K. Between 1933 and 1997, a number of advances in utilization of the MCE for cooling occurred.

This cooling technology was first demonstrated experimentally by chemist Nobel Laureate William F. Giauque and his colleague Dr. D.P. MacDougall in 1933 for cryogenic purposes (they reached 0.25 K).

Between 1933 and 1997, a number of advances occurred which have been described in some reviews:

In 1997, the first near room temperature proof of concept magnetic refrigerator was demonstrated by Prof. Karl A. Gschneidner, Jr. by the Iowa State University at Ames Laboratory. This event attracted interest from scientists and companies worldwide who started developing new kinds of room temperature materials and magnetic refrigerator designs.

Refrigerators based on the magnetocaloric effect have been demonstrated in laboratories, using magnetic fields starting at 0.6 T up to 10 teslas. Magnetic fields above 2 T are difficult to produce with permanent magnets and are produced by a superconducting magnet (1 tesla is about 20,000 times the Earth's magnetic field).

-Answers.com

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One potentially massive leap in progress was only made in 1996, "with the discovery of the ?giant? magneto caloric effect (GMCE) discovered by Gschneidner and Pecharsky in 1996."

quote:

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This led to an improvement of the refrigeration capacities of materials showing the GMCE of approximately a factor two. The development of such alloys is still undergoing substantial improvement, which makes the magnetic heating and cooling technology increasingly interesting. Sustainable applications include practical large-scale applications, such as in home refrigerators, heat pump applications, air conditioning systems, process technical systems, and automobiles, in accordance with the Kyoto protocol.

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Referenced here.

So it might well be true to say that the last two decades have held the most important developments in the field of magnetic refrigeration. This being the case, it seems flippant to dismiss some of the most recent developments as 'old news'.

EDIT: Oops, removed confusing tags from quote.

(Edited by White Hawk on 09-30-2007 14:26)

Not flippant, that which you have posted ignores all those already in operation - i.e. those which have been built and are currently being used.

As has been pointed out, such refrigerators have no moving parts - so they are not only very good for saving energy, but also have an extremely long lifetime.

NASA and the Military are prime users of such technology.

I have not said that there has not been advances in the technology itself - I have said that it has been in use for quite awhile now.

As with most things like this, it is pretty expensive to actually mass produce - more expensive than the current Frig.

As you will notice in that part that you quoted

quote:

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The development of such alloys is still undergoing substantial improvement, which makes the magnetic heating and cooling technology increasingly interesting.

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It says increasingly interesting. It does not say cost-productive. That means that basically, the technology is still too expensive to be a valid alternative to the normal frig, economically.

Now, if they can get the costs down to comparible with modern frig technology, then it will be interesting.

WebShaman | The keenest sorrow (and greatest truth) is to recognize ourselves as the sole cause of all our adversities.
- Sophocles

Yup - I don't suppose that's going to happen for a loooooong, long time...