nist-magnetic-refrigerator1As an addition to yesterday’s passive, solar powered air conditioning article, I found out today that NIST researchers (in collaboration with Chinese scientists) have a strong word to say in refrigeration technology that could revolutionize the inside components and operating cycle of that electricity guzzling, big, old fridge of yours. Well, ok, it may not be as old as I said, but the idea behind it surely is.

As I said, NIST researchers discovered a special metallic alloy made of manganese, iron, phosphorus and germanium, that works as a near-room-temperature magnetocaloric. Magnetocalorics are alloys that heat up when exposed to magnetic field. When the field is removed, their temperature drops drastically, reaching almost absolute zero in its lowest point. Until now, magnetocalorics haven’t been very useful to the refrigeration technology because the materials they were made of were the prohibitively expensive and rare metal gadolinium and arsenic, a deadly substance.

Conventional refrigerators and air conditioners contain HFCs (hydrofluorocarbons), that are greenhouse gases, contributing to global warming if released into the atmosphere. In addition to this, traditional refrigeration is becoming increasingly difficult to improve. “The efficiency of the gas cycle has pretty much maxed out. The idea is to replace that cycle with something else,” says Jeff Lynn of NIST’s Center for Neutron Research. nist-magnetic-refrigerator

The metal mixture they found already competes in efficiency with gas compression: “Understanding how to fine-tune this change in crystal structure may allow us to get our alloy’s efficiency even higher,” says NIST crystallographer Qing Huang. “We are still playing with the composition, and if we can get it to magnetize uniformly, we may be able to further improve the efficiency.”

Members of the collaboration include scientists from NIST, Beijing University of Technology, Princeton University and McGill University. Funding for the project was provided by NIST.

What would be the benefit of this technology for you? A quieter, much more energy-efficient refrigerator and air conditioning, and a much lower electricity bill. And let’s not talk about the tremendous benefits to the environment.

I wonder: what if we put a strong permanent magnet instead of the electromagnet there, and isolate it by using a bit of the energy generated by the heat the magnetocaloric alloy produces when exposed to the field? Wouldn’t we produce a much more efficient refrigerator? Even if we used grid electricity to cut off the permanent magnet’s field by shielding it with something, wouldn’t we save a lot more energy than using an electromagnet?

Think about that, and if you have an opinion, comment below.

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6 COMMENTS

  1. I want to work a refrigerator on soalr energy without using compressor
    What kind of an alternative I can have for this?

  2. typical high tech answers for low tech problems…….
    As a low tech person I would answer with something like use a bimetal plate that uses the product heat.
    heating the bimetal causes it to bend,  the perminent magnet would then move away,so removing the heat source, the bimetal cools and returns to its former position. Heypresto low tech answer for high tech problem……..

  3. Now a days we need more of such technologies which helps us to preserve our precious energy.
    Its time consuming process to bring this technology to the doors of common man.
    To make this happen more researches have to be done

  4. The fridge works by exposing a magnetocaloric material to a varying magnetic field, The alternative to an electromagnet would be a permanent magnet that was moved by a motor in and out of the range of the magnetocaloric material. I suspect it would be a similar amount of energy involved except you get the complexity and expense of moving parts.

  5. The magnetic fields required are quite large, but research into novel materials has brought that down considerably. Also, rare-earth permanent magnets, properly arranged, may be able to provide the required field. Rather than use energy to shield this field on or off, you could simply move the material in and out of the field. This requires some tricky engineering and usually another fluid to act as heat exchanger (simple water with some antifreeze is often used). Working prototype models have already been built. The trick now is to make it affordable, as some of the materials are rare, hard to manufacture, or both.

  6. Hi,

    I would think that as the magnetic fields required are *propably* pretty strong, a permanent magnet of the required type would be very costly. Could it be a part reason for the electromagnet?

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