Science

New alloy converts heat directly into electricity

A newly-created alloy (center disc) is able to convert heat directly into electricity (Image: University of Minnesota)
A newly-created alloy (center disc) is able to convert heat directly into electricity (Image: University of Minnesota)
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A newly-created alloy (center disc) is able to convert heat directly into electricity (Image: University of Minnesota)
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A newly-created alloy (center disc) is able to convert heat directly into electricity (Image: University of Minnesota)

The heat given off by electronics, automobile engines, factories and other sources is a potentially huge source of energy, and various technologies are being developed in order to capture that heat, and then convert it into electricity. Thanks to an alloy that was recently developed at the University of Minnesota, however, a step in that process could be saved - the new material is able to convert heat directly into electricity.

The multiferroic alloy, with the catchy name Ni45Co5Mn40Sn10, was created by combining its various elements at the atomic level. Multiferroic materials are known for having unique elastic, magnetic and electric properties, and in the case of this alloy, that takes a form of an usual phase change. When heated, the non-magnetic solid material suddenly becomes a strongly magnetic solid.

In a lab test, upon becoming magnetic, the material absorbed heat in its environment and proceeded to produce electricity in an attached coil. Although some of the heat energy is lost in a process known as hysteresis, the U Minnesota researchers have developed a method of minimizing that energy loss.

"This research is very promising because it presents an entirely new method for energy conversion that's never been done before," said aerospace engineering and mechanics professor Richard James, who led the research team. "It's also the ultimate 'green' way to create electricity because it uses waste heat to create electricity with no carbon dioxide."

The research was recently published in the journal Advanced Energy Materials.

27 comments
cachurro
So... what\'s the difference from an good old thermocouple?
PrometheusGoneWild.com
Efficiency? Thermocouples are about 6%. Which is enough to use them as temperature sensors. I know they are just at the beginning of this, but some numbers would be good.....
Windmaster Hiroaki
Something that converts heat DIRECTLY into electricity??... boy, this is good... no wait, potentially revolutionary, if they can keep the numbers look good...
limbodog
Yes, some numbers would be very good, but I still think this seems like a better solution than a thermocouple. If you could coat the object in question in a layer of this and have perfect contact, it seems to me you\'d have a better chance of turning more of the heat into electricity. (not that I know, but I\'m guessing) In any case, I am excited to see this. Sounds like good progress in the right direction.
Mindbreaker
If it is over 30% it would be great for solar reflecting dishes. That saves a lot of expense and complication over heat engines. At 40% it would blow them out of the water. Of course, making the material in bulk may not be so easy. The elements themselves don\'t look too costly. A lot of details left out. If it is 5% efficient that would not be much of a game changer. Peltiers can work in reverse, I wonder it this can be coaxed to as well. Could make a good cooler. I am probably dreaming.
Mindbreaker
I meant by cooling, not by heating ;)
WildZBill
I wouldn\'t get my hopes up. The process seems to be a sudden change in magnetic properties at reaching a certain temperature. This would create a single magnetic pulse, inducing a single electrical spike. This could be measured, but not useful. You need a cyclic induction to get useful power out. Perhaps if they find a way for this material to swiftly oscillate between magnetic states it would become useful, but in most cases thermal reactions are quite slow.
George Swan
If this material could be buried under pavement, wow! Roads and parking lots turn into electricity generators. How about roof tops? Stay tuned!
Blixdevil
So, no moving parts? Another application (if it indeed is more efficient than a thermocouple) would be deep space probes. They currently run on electricity from thermocouples that get their heat source from atomic decay.
Joshua West
this would be perfect for a company with lasers and heating homes
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