Magnetic Cooling For Your Fridge

Your refrigerator’s humming, electricity-guzzling cooling system could soon be a lot smaller, quieter and more economical thanks to an exotic metal alloy discovered by an international collaboration working at the National Institute of Standards and Technology (NIST)’s Center for Neutron Research (NCNR).*

The alloy may prove to be a long-sought material that will permit magnetic cooling instead of the gas-compression systems used for home refrigeration and air conditioning. The magnetic cooling technique, though used for decades in science and industry, has yet to find application in the home because of technical and environmental hurdles—but the NIST collaboration may have overcome them.

Magnetic cooling relies on materials called magnetocalorics, which heat up when exposed to a powerful magnetic field. After they cool off by radiating this heat away, the magnetic field is removed, and their temperature drops again, this time dramatically. The effect can be used in a classic refrigeration cycle, and scientists have attained temperatures of nearly absolute zero this way. Two factors have kept magnetic cooling out of the consumer market: most magnetocalorics that function at close to room temperature require both the prohibitively expensive rare metal gadolinium and arsenic, a deadly toxin.

But conventional gas-compression refrigerators have their own drawbacks. They commonly use hydrofluorocarbons (HFCs), greenhouse gases that can contribute to climate change if they escape into the atmosphere. In addition, it is becoming increasingly difficult to improve traditional refrigeration. “The efficiency of the gas cycle has pretty much maxed out,” said Jeff Lynn of NCNR. “The idea is to replace that cycle with something else.”

The alloy the team has found—a mixture of manganese, iron, phosphorus and germanium—is not merely the first near-room-temperature magnetocaloric to contain neither gadolinium nor arsenic—rendering it both safer and cheaper—but also it has such strong magnetocaloric properties that a system based on it could rival gas compression in efficiency.

There's GOT to be more applications than jsut our fridges...hmmm. What about air conditioning? Or...

I wonder how much power this needs.