From the University of Minnesota via Eurkealert today, this looks interesting:
University of Minnesota engineering researchers discover source for generating ‘green’ electricity
University of Minnesota engineering researchers in the College of Science and Engineering have recently discovered a new alloy material that converts heat directly into electricity. This revolutionary energy conversion method is in the early stages of development, but it could have wide-sweeping impact on creating environmentally friendly electricity from waste heat sources.
Researchers say the material could potentially be used to capture waste heat from a car’s exhaust that would heat the material and produce electricity for charging the battery in a hybrid car. Other possible future uses include capturing rejected heat from industrial and power plants or temperature differences in the ocean to create electricity. The research team is looking into possible commercialization of the technology.
“This research is very promising because it presents an entirely new method for energy conversion that’s never been done before,” said University of Minnesota 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.”
To create the material, the research team combined 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 in a University of Minnesota lab, the new material created by the researchers 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 phase transformations. The team’s research was recently published in the first issue of the new scientific journal Advanced Energy Materials.
Watch a short research video of the new material suddenly become magnetic when heated: http://z.umn.edu/conversionvideo
In addition to Professor James, 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.
“This research crosses all boundaries of science and engineering,” James said. “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.”
Funding for early research on the alloy came from a Multidisciplinary University Research Initiative (MURI) grant from the U.S. Office of Naval Research (involving other universities including the California Institute of Technology, Rutgers University, University of Washington and University of Maryland), and research grants from the U.S. Air Force and the National Science Foundation. The research is also tentatively funded by a small seed grant from the University of Minnesota’s Initiative for Renewable Energy and the Environment.
For more detail on the research, read the entire paper published in Advanced Energy Materials at http://z.umn.edu/energyalloy.
The Direct Conversion of Heat to Electricity Using Multiferroic Alloys
Vijay Srivastava1, Yintao Song1, Kanwal Bhatti1,2, R. D. James1,*
Abstract
We demonstrate a new method for the direct conversion of heat to electricity using the recently discovered multiferroic alloy, Ni45Co5Mn40Sn101. This alloy undergoes a low hysteresis, reversible martensitic phase transformation from a nonmagnetic martensite phase to a strongly ferromagnetic austenite phase upon heating. When biased by a suitably placed permanent magnet, heating through the phase transformation causes a sudden increase of the magnetic moment to a large value. As a consequence of Faraday’s law of induction, this drives a current in a surrounding circuit. Theory predicts that under optimal conditions the performance compares favorably with the best thermoelectrics. Because of the low hysteresis of the alloy, a promising area of application of this concept appears to be energy conversion at small ΔT, suggesting a possible route to the conversion of the vast amounts of energy stored on earth at small temperature difference. We postulate other new methods for the direct conversion of heat to electricity suggested by the underlying theory.
Oops. Waste heat is just that: waste heat, the end of the flow of usable energy. What these people discovered is a new material that becomes magnetic at a certain (high) temperature, and then produces a negligible voltage blip once. In order to make energy, the material must go through its off state again, producing a reversing current, and then on again (hysteresis), which through conduction is a very slow and wasteful process. The amount of energy harvested this way can never be of any use.
I am still waiting for the first “green technology” that doesn’t consume more (fossil) energy than it produces during it’s rated life cycle, independent from sun light or wind. Wake me up when they have found one and I will buy it immediately.
Scott Covert, here it is: http://www.flexenergy.hu/en/products.html Its a generator producing 38 KW at 50 Hz.
Seems to me that the device has to spin in and out of a waste heat environment. If it spins too rapidly the temperature differential will be too small to create the desired effect. So it needs to spin fairly slowly giving a very low magnetic to electric output. No, I don’t think that i will be buying one of those.
How do you get charge separation in a homogenous alloy?
Let us suppose it scales by weight.
3 g = .6 mV pulse
30g = 6 mV pulse
30Kg = 6 V pulse
That is about 66 lbs. for pulses. I could see this as a sensor. As a generator? Not so much.
Is this another indication the current solar power industry may be nearing the Beta Max destiny.
From the comments here, it looks like I’d get more electricity from my car’s tailpipe if I put a tiny turbine generatior in it. 🙂
How dirty are these materials to work with? How much toxic waste is generated that has to be disposed of? That’s why photovoltaicsare moving to China. Just dump the highly toxic wastes in the nearest landfill.
Saad,
Naval research does fund a lot of research into this area and there are existing waste heat generation systems in use. A direct means of producing electricity from waste heat would be a significant advancement.
Crosspatch
The biggest problem with the heating and cooling 50-60 times a second is not so much developing a flap or valve to control the flow, but the thermal and pressure effects on the heat exchanger. The heat source and the cooling medium will be flowing through some form of expansion joints, and the cyclic stress will cause significant fatigue failures.
Perpetual motion machine of the second kind.
Hmm, There’s a catch there – it may be out-of-date. From http://www.e-catworld.com/2011/05/24/caltech-researchers-develop-thermocouple-twice-as-efficient-as-exisiting-technology-rossis-interested/ I found in part:
More about that is at http://www.physorg.com/news/2011-05-high-performance-bulk-thermoelectrics.html which says in part:
Let’s file that one away for future reference.
Can we install a prototype unit to capture congressional hot air?
Unlimited energy!!!
At least two problems not counting any technical difficulties in suitable sources of heat or operating efficiency.
First is we (USA anyhow) don’t really need new ways of generating electricity. We need new ways of storing it, distributing it, and using it. Generation is the least of our concerns. The only people worried about electricity are misguided CO2 hysterics. Liquid hydrocarbon fuels that are drop-in replacements for existing fuels is what we need both for energy security in the near term and in the mid term the eventual economic infeasibility of pumping oil that’s ever harder to get at and more difficult to refine.
The second problem is these devices appear to be far too expensive to manufacture with copper windings, niobium permanent magnets, and an exotic multi-ferrous alloy so precious the researchers didn’t cut or shape it after making it because that would have wasted some of it. They used a piece less than a centimeter in diameter.
I’m moderately skeptical. It seems alike a lot of work and a lot of material to coax out something that doesn’t work better than thermoelectric devices.
A couple notes on notes:
How can anyone finish reading WUWT any more?
http://www.metalprices.com/FreeSite/metals/nickelalloy/nickelalloy.asp has some current prices, and some 2007 prices, sigh. Subscription required for current prices.
Ni $10/lb, Co $40/lb, Mn $0.85/lb, Sn $11/lb
Lead (for Lead telluride in my previous comment): Pb $1.10/lb. Don’t know about Lead telluride, probably expensive. PbTe is the mineral Altaite.
I bought my wife a good Christmas present – a woodstove fan powered by a thermoelectric cell. I see today it’s likely PbTe, and not thermocouples as the cell
is flat, thin, and a couple inches square.
http://www.envirogadget.com/home-gadgets/ecofan-heat-powered-wood-stove-fan/
Neat device – the fan speed tells you approximately how hot the stove is.
Alex the skeptic says:
June 22, 2011 at 1:56 pm
> Scott Covert, here it is: http://www.flexenergy.hu/en/products.html Its a generator producing 38 KW at 50 Hz.
Cute, but it doesn’t say anything about using waste heat, just waste inflammables – “Its fuel supply is very versatile, it works with basically any type of combustible gasous fuels: natural gas, biogas, methane, landfill gas, furnace gas, wood-gas, flare gas, synthetic gas, hydrogen, volatile organic compounds and even liquid fuel.”
Sounds vaguely like what some Italians proposed and revealed not long ago.
Great Bullshit!!!!
I’m sure there will be uses for a material that can change phase from non-magnetic to magnetic with the application of a little heat, even if it’s not direct power generation.
WRT tail pipes, I had the idea (and published it in a letter to a UK car magazine nearly 40 years ago) of splitting a turbocharger so that the exhaust side could drive a small (fast!) generator and the induction side would be driven by an electric motor. This would eliminate turbo lag and provide a replacement for the usual alternator, as there would be power generated whenever the engine was running. You’re welcome to try it, but please remember me if it works!
When they say short video, they mean short video. Don’t blink. At 4 seconds, you see a piece of metal jump in the “short” video. But, it apparently also represents the capability of a very quick change in magnetism created by this new discovery.
Perhaps it could replace solar panels in space. Something like a double sided board that rotates at an appropriate speed – the side catching the sun heating up and the side in shadow cooling down.
Might be a good application for radio thermal generators (RTG) in outbound exploratory spacecraft. Currently they use uber-expensive plutonium to generate about a 1000F temperature gradient across a thermoelectric (dissimilar metals in contact like a thermocouple) bank. The high operating temperature produces material degradation problems that are expensive to work around in and of themselves. Even at that operating temperature they are only about 5% efficient and are so heavy they usually comprise about half the payload. The researchers here claim this novel thermo-electric effect is comparably efficient with conventional thermo-electric materials per degree of temperature gradient. The larger claim is that it’s only a tenth the weight of conventional thermoelectrics. That could save big bucks in deep space exploration as much of the cost of the projects is in lifting the payload mass past escape velocity. But I just don’t see it having practical application elsewhere. One astute commenter here mentioned he could see it as a sensor but not as a generator. He was right on the money equating this with a common thermocouple which generates a measurable voltage but except in exotic applications are not used to generate usable amounts of power.
Ric Werme says:
June 22, 2011 at 3:02 pm
“I’m moderately skeptical. It seems alike a lot of work and a lot of material to coax out something that doesn’t work better than thermoelectric devices.”
The major claim is (quoted from the paper) “The predicted power density of an optimized device is more than an order of magnitude greater than thermoelectrics with the highest known ZT value.”
So basically it weighs a lot less than the thermoelectric banks that go into RTG power supplies. Same power from same source of heat but a lot less weight.
Ric Werme says:
June 22, 2011 at 2:37 pm
“One example is the charging system. The electricity to keep your car’s battery charged is generated by the alternator, a mechanical device driven by a rubber belt powered by the crankshaft. You’ve got friction, slippage, strain, internal resistance, wear and tear, and weight, in addition to the mechanical energy extracted to make the electricity. Just replacing that one subsystem with a thermoelectric solution could instantly improve a car’s fuel efficiency by 10 percent.”
This is key. What is on offer here may be somewhat greater efficiency: not actual additional production of usable energy, but less energy used to achieve a given goal, in this case, producing motive power to transport goods and people. Greater efficiency is generally good, if there are no secondary penalties (maintenance, reliability, etc…). Like Floor Anthoni said, waste heat is waste heat, but maybe you can generate less of it overall.