December 14, 2006
Today's News Yesterday...
...that's what this blog brings you.
One material works nicely: the element gadolinium (Gd). It's a silvery-white metal that's strongly attracted by a magnet, has a magnetic disordering temperature of 20C, and a giant magnetocaloric effect of several degrees. A waste product from permanent magnet manufacture, gadolinium costs around £100 per kg; a magnetic fridge would use 0.15kg. Sandeman's current research, however, is looking at other possibilities.
"The quest is to get away from these expensive rare earth materials and look for magnetic materials which have a phase transition at room temperature," says Sandeman, whose research job at Cambridge University is funded by the Royal Society. He also works with Professor Derek Fray, a leading expert in materials chemistry. "What I'm actually working with is an alloy of two magnetic materials, cobalt and manganese," says Sandeman.
This blog, April 2005:
Another is the work on gadolinium based magnetic refrigeration, still in its infancy, but we know it works.
BTW, anyone who thinks that gadolinium is £100 per kg in quantity needs their head examined. Rare earth metals should be just above twice the cost of the oxide they are made from.
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Interesting, even though the article didn't once even hint at why the fridge should use less energy than a conventional one. In the modern overheated British kitchen, I'd have thought that an absorption refrigerator using the central heating flue gas would run essentially "free", though the plumbing and safety concerns would be a bugger. And you'd need back-up for the summer months. In fact, it's such a silly bloody idea that there must be a "green" grant available from somewhere.
Posted by: dearieme | Dec 14, 2006 12:59:10 PM
Thallium, polonium, gadolinium - I love it when exotic metals get into the news.
Posted by: johnnybonk | Dec 15, 2006 3:04:27 AM