University of Minnesota (UM) engineering researchers in the College of Science and Engineering have recently discovered a new alloy material that converts heat directly into electricity.

Getting from heat to electric power has a loss of the energy i.e. steam to turbine to generator with each step having energy losses of significance that the UM discovery may well skip in a working model.  The game is still about efficiency, but one alloy is found that can offer much further research, insight and innovation.  Step one is usually the hardest – getting from heat to electricity is now a now one step reality.  There’s a lot to learn, and now we have a place to start.

UM Aerospace Engineering and Mechanics Professor Richard James, who led the research team said, “This research is very promising because it presents an entirely new method for energy conversion that’s never been done before. It’s also the ultimate ‘green’ way to create electricity because it uses waste heat to create electricity with no carbon dioxide.”

Should development come quickly waste heat might be gathered taking efficiencies further.  Such devices could replace cooling towers, hot effluents, – all the range of cooling that spirits heat off into the atmosphere.

Multiferroic Energy Conversion Device. Click image for more info.

The UM team made the new alloy by combining elements at the atomic level to create a new multiferroic alloy, Ni45Co5Mn40Sn10. Multiferroic materials combine unusual elastic, magnetic and electric properties. The alloy Ni45Co5Mn40Sn10 achieves multiferroism by undergoing a highly reversible phase transformation where one solid turns into another solid. During this phase transformation the alloy undergoes changes in its magnetic properties that are exploited in the energy conversion device.

During a small-scale demonstration, the new material begins as a non-magnetic material, then suddenly becomes strongly magnetic when the temperature is raised a small amount. When this happens, the material absorbs heat and spontaneously produces electricity in a surrounding coil.

Some of this heat energy is lost in a process called hysteresis. A critical discovery of the team is a systematic way to minimize hysteresis in the phase transformations.  The team’s research has been published in the first issue of the new scientific journal Advanced Energy Materials.

A pdf file of the full paper is downloadable here.

Here again is a cross-disciplinary team with an astonishing result.  Professor James said, “This research crosses all boundaries of science and engineering. It includes engineering, physics, materials, chemistry, mathematics and more. It has required all of us within the university’s College of Science and Engineering to work together to think in new ways.”

Multiferroic Energy Conversion Team Members. Click image for more info.

With James the other members of the research team include University of Minnesota aerospace engineering and mechanics post-doctoral researchers Vijay Srivastava and Kanwal Bhatti, and Ph.D. student Yintao Song. The team is also working with University of Minnesota chemical engineering and materials science professor Christopher Leighton to create a thin film of the material that could be used, for example, to convert some of the waste heat from computers into electricity.

In the lab, University of Minnesota researchers show how a new multiferroic material they created begins as a non-magnetic material then suddenly becomes strongly magnetic as the piece of copper below it is heated a small amount. When this happens, it jumps over to a permanent magnet. This demonstration represents the direct conversion of heat to kinetic energy.

The new multiferroic alloy is a major step to the complete use of heat.  While no efficiency factor is available yet, cost estimate, or engineering designs for working models, the news deserves some acclaim.  Which begs the question, who can top this with what?

A great job, and a giant step. Congratulations.


2 Comments so far

  1. Craig Binns on June 24, 2011 5:43 AM

    At least one “thermoelectric” direct heat to electricity device is in current production – the biolite stove which is an efficient fan-enhanced wood cooking stove. The fan is driven by the heat of the burner. And surplus electric power can be drawn off for battery charging, LED lamps, etc.

    Models have been designed and are being marketed as a camping stove, and as a household cook stove to off grid users in places like India. I don’t know when it will be available in Europe or N America, and haven’t been able to find out.

    This principle would work very well in the wood pellet stoves used for cooking and central heating particularly in Italy and Canada. These at present depend on mains power for air circulation and pellet delivery to the burner, and so they inconveniently fail in the event of power cuts.

  2. sapian on December 2, 2011 8:02 PM

    very interesting development, good job. can u possilbly put the material on the heat source with a magnet suspended above and allow the material to go through a coil to produce an emf, then cool, drop and recycle. just a thought ty

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