Magnetocaloric energy

[PaulLowrance]

Numerous people have asked what Magnetocaloric energy is so I was uncertain where to post it. Here's a brief description.

Magnetocaloric energy is the energy that's exchanged during the Magnetocaloric effect, an effect contained within all magnetic materials. This varies between magnetic materials. Ideally you want material that has inherently high potential energy. This amount of inherent energy is determined by crystal structure of intrinsic electron spins. Ideally, the best type of material is one where the moments are in chaos with no applied field, but turn ferromagnetic with an applied field. Such a state of chaos offers the highest potential energy state. A fully saturated ferromagnetic material offers the lowest potential state. That's why Gadolinium offers one of the best Magnetocaloric materials because at room temperature very few of the magnetic moments are in alignment. This lack of alignment offers high potential energy. When the field is applied the magnetic moments align, which is where the kinetic energy arises.

So how much energy are we talking about? Gadolinium compounds can change 7 F per 1/4 cycle. I calculated that one cubic inch of such material exchanges 115.8 J per quarter cycle, which is 463.2 J per cycle. At 100 KHz there's 46320000 (46.32 MJ) joules per second or 46.32 million watts. That is a whole lot of energy exchange per second in just one tiny cubic inch of material my friend!  Now granted iron at room temperature does not exchange that much energy, but it's not terribly far off.

So where is the energy going? IMHO most of the energy exchange occurs by radiation. What is happening is electrons and atoms are flip during avalanches. This generates a wide bandwidth of radiation typically hundreds of MHz. The electron is a magnetic moment. When it flips it generates electromagnetic waves. Most of this energy is absorbed by nearby atoms in the crystal structure.

The trick is to prevent the magnetic material from absorbing the radiation. I know a person who knows exactly how to do this. It uses conventional science. This is very real and has been known for over one month now. The only reason I can now tell you this is because this information is now secured. If I for example am removed from society then this research will be revealed in its entirety.

Paul Lowrance

[rapttor]

Paul, very interesting topic.. although I can't discuss this at the level of which you have educated yourself to, I do find the subject facinating. Here's a question though, where does a person obtain "Gadolinium" & what are the steps involved?
Reminds me of Bill Muller's http://www.mullerpower.com/index2.php work with amorphus metal coils that he came up with for his dynamo generator, which have no magnetic properties until used in an em field. Bill came up with these to reduce the "cogging" issue in his generator & motor, and reduce eddy currents drag when using regular iron cores.


regards,
art meuse

[PaulLowrance]

Hi raptor,

Gadolinium is extremely expensive, roughly 30 times the price of gold. Although there are cheap magnetic materials who's curie temperature is at or near room temperature such as MnZn ferrites. I believe the higher percentage of MnZn usually equates to lower curie temperatures. There are companies that sell such magnetic materials, but I'm still investigating / searching. A company named Amidon makes high permeability ferrites containing a little MnZn who's curie temperatures are as low as 120 C.  We could only guess how effective that is.

I would very much appreciate if anyone knows of low curie temperature magnetic materials for sell. Usually the higher the permeability equates to lower curie temperatures, but that's not always the case.

Basically the ideal material is one in which the magnetic moments are in disorder. Several factors determine this such as atomic bond strength. The perfect material is one that has highest saturation and maximum disorder. Of course, higher saturations means your circuit must deliver higher currents to saturate the material. The amount of radiated magnetocaloric energy is basically equated to the level of disorder prior to saturation verses the level of saturation.

An example of how this works is to think of two PM's (permanent magnets), each on swivels. Maximum disorder is equal to both PM's rotated so they are repelling each other. Of course you cannot achieve that level of disorder even in Gd (Gadolinium). So the PM's are repelling. Now if you release the PM's they will quickly rotate so they are in alignment. As the PM's rotate they are accelerating; i.e., we are converting potential energy to kinetic energy. This conversion from PE to KE is Magnetocaloric energy. On an atomic scale there are frictions and other factors involved.

So now the PM's are tightly aligned and you may ask how do we start over again and get the PM's rotated out of alignment. The answer is in ambient temperature. At room temperature the atoms are violently vibrating. It is because of this ambient temperature that knocks the spins out of alignment while the applied magnetic field is lowered. Nearly all the energy responsible for knocking the spins out of alignment comes from ambient temperature. This is exactly why the temperature of the magnetic material lowers when the applied field is removed.

That is the complete Magnetocaloric effect.

Paul Lowrance