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.
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@scientistfortruth
“Of course a heat engine can work with water heated by solar irradiation, but as you well know the maximal efficiency will be very low if the heat sink is at ambient temperature. But that’s not my point: my point is, as readers can see for themselves, that devices that can produce electricity from heat cannot possibly be in breach of the Second Law, as some commenters were suggesting. That, after all, is how we produce nearly all our electricity today.”
The maximal theoretical efficiency would be very low. The maximum efficiency in practice is a negative number. Solar energy, being free for the taking, is not a limiting factor. If you get 1% efficiency that would be fantastic because the input energy is free for the taking so you’d just scale it up to get the desired power output. In the real world you have to factor in construction, maintenance, and operating costs which is what turns any theoretical positive efficiency number into a negative number. If it weren’t for those real world engineering concerns we could do all sorts of nifty things like use solar heated warm water to heat a column of air rising into a hot air balloon which has a tether wound around a driveshaft so that when the balloon was released it would spin the driveshaft. Add a second balloon with a tether wound in the opposite direction and release that balloon when the first balloon neared its apex it would reverse the spin on the shaft and rewind the first tether as the first balloon descended giving you a constantly repeating spin cycle. Use of a simple tranmission gear to a second driveshaft would make the second shaft spin in the same direction all the time. Hook that up to an alternator or generator and there you go – low quality heat generating any amount of electricity you wanted. Alas, the engineering realities we must take into consideration make such things a practical impossibility but admittedly they’re fun to imagine and only become a problem when someone who doesn’t why they won’t work in practice wastes time and money finding out the hard way why they aren’t practical or they do it just because they find someone or some government agency foolish enough to pay them to develop it. All sorts of expensive boondoggles happen in just that manner.
Of course Carnot’s Theorum (sorry for calling it Carnot’s Law) doesn’t apply to solid state devices such as the gadget in the OP but so far, and this gadget is no exception, no solid state conversion of heat to electricity has ever approached the attainable efficiency of mechanical heat engines. At best the solid state devices are an order of magnitude lower efficiency (6% vs. 60%) and that’s with the same “high quality” heat employed by typical pratical heat engine designs.
The BIG problem with using solar heating to drive a heat engine is precisely described by the difference between low and high quality heat. Raw insolation is low quality so in order to get a heat engine operating in a positive efficiency domain you have to somehow concentrate the low quality heat into high quality heat. Various attempts using mirrors and lenses have been tried and tried again with some limited success but other factors not related to driving the generator still make it impractical. The best attempt so far is an installation in some western desert utilizing a field of mirrors which track the sun and direct the concentrated light onto a vat of molten salt which in turn serves as the heat source for a heat engine that drives a generator. Problems abound which still render it impractical. The capital cost is large, operating and maintenance costs are large, suitable locations are remote and not serviced by existing high tension transmission lines requiring even more capital to build those, and storage of sufficient amount of heat when the sun isn’t shining so that supply can be matched to demand combine into showstoppers. Smaller installations with a single parabolic mirror or fresnel lens driving a stirling engine make for some fascinating reading and great fun for the garage tinkerer but alas, except in cases where there is no grid from which to draw conventionally generated electricity, these too have less practical value than entertainment value for garage inventors.
Dave Springer:
At June 24, 2011 at 4:11 am you question my having said;
“A useable high temperature superconductor would change civilisation more – and more rapidly – than the industrial revolution.”
by asking me
“How so? It would make electrical generation, storage, and transmission much more efficient to be sure and electric motors would be more effecient as well. If I thought about it for a while I could figure out how it might benefit computer design too but I don’t see how that translates into changing the world more and more rapidly than the industrial revolution. Copper losses just aren’t that big of a deal. What am I missing?”
I answer; you are “missing” almost everything.
Electrical generation, transmission and useage would each gain efficiency improvement. Only the use of electricity for heating would not benefit.
The result would be equivalent to at least doubling the availability of electricity while reducing the cost of electricity by at least half. And there would only need to be infrastructure amendment: n.b. not infrastructure construction.
All human activity is enabled by energy supply and limited by material science. A step change in the availability of cheap energy enables a resulting step change in human activity.
The industrial revolution happened when the energy available in fossil fuels became useable by means of the steam engine. That required immense and expensive infrastructure construction (e.g. railways and factories).
I repeat: the novel material we need is a room-temperature superconductor, and the monies being thrown away on AGW so-called ‘science’ could be put towards finding such a material.
Please note that this is a statement of the blindingly obvious. It is not a plee for me to get research grants: my employment as a research material scientist ceased in 1995.
Richard
@richard Courtney
So you think room temperature superconductors halving the cost of electricity, a point I don’t dispute, would change the world more and more rapidly than the industrial revolution?
I’m not buying it. Electric power represents 41% of U.S. energy consumption:
http://en.wikipedia.org/wiki/File:USenergy2009.jpg
Halving the cost of electricity is not a world altering event. If it were then we should have seen the opposite effect as the cost of petroleum quadrupled (or more) over the past two decades.
I’m afraid you’re going to have to give me a lot more than just less expensive electricity to convince me that a cheap ductile room temperature superconductor is going to change more and more rapidly than the industrial revolution.
I believe genetic engineering is going to bring off that feat. Once we are able to turn microbes into programmatically controlled self-reproducing self-maintaining slave labor forces able to build just about anything we want or need with molecular precision that will make the industrial revolution look puny in comparison. It will also make cost of energy plummet far more than any hypothetical room temperature superconductor as microbes can manufacture, pretty much for free, any hydrocarbon molecules we desire limited only by sunlight, water, and source of carbon. There will come a day in the not too distant future where instead of governments wanting to tax CO2 emissions they’ll be driven into regulating CO2 consumption as that is and will continue to be the primary source of source of carbon for living things including our GM microbes. The state of the art in genetic engineering is quickly approaching this point. This is not particularly new thinking. It’s been called the coming era of nanotechnology for about 25 years. A roadmap was laid out in the 1986 book “Engines of Creation” by K. Eric Drexler and colleagues in an MIT think tank. I read the book in 1987 and have been watching the roadmap being followed since that time. It has been remarkably accurate in both timing and sequence of milestone events. If I might humbly suggest reading the original work so you can see for yourself how prescient it was it’s available for free in its entirety here:
http://e-drexler.com/d/06/00/EOC/EOC_Table_of_Contents.html
I consider this the most influential book on high technology I’ve ever read and probably the most influential I ever read without qualification.
Anthony,
275C is not waste heat. Most commercial steam turbines pull a vaccum on the last stage to get the last watt out of the steam, and the cooling is done at temps below 100C. 275C would require the exhaust of an internal combustion device, usually only used on vehicles. Most smokestack gas is around 200C or below. There are of course stationary IC motors, only continuously used in pipeline compressors and backup Diesel generators.
Not much of a future here, in my opinion.
Wonderful animation of first steam engine used to pump water out of mine shafts.
http://en.wikipedia.org/wiki/Newcomen_steam_engine
I actually built a table top model of one of these from scratch a few years ago with some modifications to use very low quality heat. It might not be obvious to everyone but the power stroke is when the steam condenses back into water which creates a vacuum inside the cylinder and external atmospheric pressure drives the piston downward with a nomimal force of 14.7 pounds per square inch of piston surface.
The Newcomen engine requires a boiler that operates at a temperature high enough to produce steam that’s hot enough to not immediately condense when it enters the cylinder which means you have to keep the cylinder at an operating temperature very near 212F. Since cylinder is cooled by water injection on the power stroke you have to first add enough heat to bring the cylinder temperature back up above boiling point before the cylinder will start to fill with steam again.
The modification I made was to put the cooling water on the outside of the cylinder and pump the air out of the dead space in the boiler before starting it up so it would operate with a partial internal vacuum. The partial vacuum I used lowered the boiling point of water down to something reasonably attainable by passive solar hot water heaters i.e. about 170F. For an energy source that I could precisely monitor instead of solar heated hot water I put a standard electric hot water heater element inside the boiler. I then used a dimmer switch to control how much power went into the heater element and a voltmeter for measuring it. Power output could be easily measured by a simple calculation taking the mass of the counterweight and distance travelled over time.
I also modified it to be pistonless and valveless except for a stop-valve so the system could be iniatilized to a partial vacuum on startup. I did this by using a second vessel on the other side of the rocker arm and a steel pipe as the rocker arm itself. Steam pressure on the hot side would push the water out of the heated vessel into the unheated one and on the cooling stroke the water would drawn back over to the boiler side.
With a suitable flywheel and connecting rod from the rocker arm you can spin a shaft connected to a generator or you can ditch that and use a linear generator. A linear generator would be far better as there are very substantial losses involved in the gearing needed to obtain rotational energy.
It worked even down to close to room temperature water in the boiler depending on the quality of the vacuum I started out with. What bites you in the butt is that the latent heat of vaporization decreases as the temperature of the steam decreases. Thus it takes an impractical amount of energy to reheat the cylinder and piston face at the bottom of the power stroke, or in my case reheat the water from just below boiling temperature to just above it.
According to my calculations in order to get a kilowatt of electricity out of it I’d need a rocker assembly with 10 feet of vertical travel, 500 gallon pressure vessels that wouldn’t collapse in an internal vacuum, and 1000 square feet of passive solar water heating. And even then I’d only get a kilowatt out of it at high noon. Pipe friction also becomes an issue so you need a pretty big diameter pipe for the rocker arm to minimize losses there.
However, it was still tempting because it’s cheap to store low quality heat in a large insulated water tank so you can basically keep your solar heater going all day long heating a big holding tank and draw on that whenever you need to generate power. You can also add a burner to it (wood, gas, coal, whatever) to bring the water temperature up when the sun isn’t giving you enough energy. Even on a string of cloudy days you can revert to fire heated water to keep your electrical generation capacity in sync with demand. Unfortunately you need a few tens of thousands of gallons of hot water storage so we’re talking about a heat storage unit the size of an Olympic swimming pool.
Alas the cost and space required to do all this just isn’t worth it when you’re connected to a grid with all the electricity you want at $0.11kwh 24 hours a day 7 days a week 365 days a year.
But hey, at least I gave it the old college try. Commensurate with collegial spirit I cannabalized the experimental apparatus and made a great room temperature vacuum still that could turn a gallon of cheap wine into 1.5 pints of 100+ proof grape brandy and 3.5 quarts of denatured wine with no off flavors in about 15 minutes. Vacuum distillation with low quality heat, unlike electricity generated from low quality heat, was a ripping success. In fact I’m pretty sure I could generate electricity cheaper and more efficiently with low quality heat by growing grapes, using solar powered vacuum distillation to obtain high quality ethanol, and using the ethanol to fuel a portable internal combustion generator. Cheers.
Michael Moon says:
June 25, 2011 at 8:01 am
Anthony,
“275C is not waste heat. Most commercial steam turbines pull a vaccum on the last stage to get the last watt out of the steam, and the cooling is done at temps below 100C.”
There’s a tradeoff. You DO NOT want water droplets hitting the final stage turbine blade tips at high velocity. This causes erosion and premature failure. The steam needs to be kept totally dry at the turbine outlet. Anything below about .5 bar is flirting with trouble as the pressure is not constant at all points within the cylinder. The cost of additional hardware to avoid droplet erosion is a case of diminishing returns.
http://www.mechanicalengineering4u.com/?tag=steam-turbine
Dave Springer:
At June 25, 2011 at 7:08 am you assert:
“Halving the cost of electricity is not a world altering event. If it were then we should have seen the opposite effect as the cost of petroleum quadrupled (or more) over the past two decades.”
So, you think the “cost of petroleum quadrupled (or more) over the past two decades” has not inhibited industrial development? Evidence please.
Cheap, available energy enables activities that expensive and/or unavailable energy prevents. Therefore, it is reasonable to assume that development would have progressed faster if the cost of petroleum had not quadrupled (or more) over the past two decades.
Room temperature superconductors would enable large scale electricity storage and that alone would dramatically reduce the need for power stations. Indeed, there is no activity that would not benefit from development of cheap and abundant room temperature superconductor materials.
I add that your several and verbose posts are very strong on assertion but lacking in substance. We all have opinions: I have some that I have stated here. And debate of opinions is healthy. But portraying opinions as facts is not helpful.
Richard
Richard S Courtney says:
June 25, 2011 at 2:52 pm
“So, you think the “cost of petroleum quadrupled (or more) over the past two decades” has not inhibited industrial development? Evidence please.”
Don’t put words in my mouth. Of course it inhibited industry. My point was that it didn’t cause a collapse of the industrial revolution. Your position that a room temperature superconductor will change the world more than the industrial revolution is absurd. Energy price is important but it isn’t THAT important. If it were industrial activity would have virtually ground to a halt when oil quadrupled in price over the past few decades. Cost of electricity is no more or less important than cost of oil.
My patience with you is growing thin.
Richard S Courtney says:
June 25, 2011 at 2:52 pm
“Room temperature superconductors would enable large scale electricity storage and that alone would dramatically reduce the need for power stations. Indeed, there is no activity that would not benefit from development of cheap and abundant room temperature superconductor materials.”
What?
That’s the same as saying having a piggy bank greatly reduces the need to earn money.
Caution: Make sure brain is engaged before putting mouth in gear.
Power storage and transmission are probably the greatest single advantages that a suitable room temperature superconductor would provide. Other things that rely on superconductors, such as medical imaging systems, would get cheaper to build and operate too but the scale of power generation and distribution makes those much more important.
Superconducting electrical storage rings were pop science at least as early as 30 years ago as evidenced by this January 1989 Popular Science Magazine cover story:
http://books.google.com/books?id=sfQCZ2JhzawC&pg=PA66&lpg=PA66&dq=pop+science+superconducting+storage+ring&source=bl&ots=Or3e12srz7&sig=CN-YvvsWm1xBJXp26mBBzOgLnlU&hl=en&ei=82MMToLjIYictwfG5PDkDQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CB8Q6AEwAA
Of course it was never actually built and to this day remains pie in the sky.
Storage and distribution of electricity are vexing problems for solar power generation schemes and energy density of batteries is a vexing problem for vehicular propulsion with electric drive motors. A superconducting storage battery would be a boon for electric cars and trucks but transportation is still transportation and internal combustion motors do a fine job at it. Electric vehicles have few if any cost advantages. Large scale storage would eliminate one problem with solar power generation in that excess power generated while the sun is shining could be economically stored to meet demand when the sun isn’t shining. It would also mitigate a second problem in that the best places to generate solar power are generally remote from point of consumption so a better transmission system would be helpful. As well, if people start using electric vehicles en masse the demand on the power grid would rise tremendously and the current grid couldn’t handle the increased load – it’s running close to capacity as it is. Room temperature superconductors that don’t break down under high current load would allow the existing to be upgraded enormously in capacity without changing the ground footprint of the tranmission pathways.
But transmission losses today are only 10-20% of total losses so that constitutes a ceiling on how much efficiency can be gained through superconducting transmission lines. Electrical storage is effectively accomplished today through the fuels which drive the generators. It’s not instantaneous as superconductor storage rings would be but it’s pretty adequate nonetheless.
One primary problem remains. Superconductors won’t help very much in the generation of electricity and unless you can generate more electricity storage and transmission improvements won’t help any more than buying a piggy bank will reduce the need to earn an income. Without an income there’s nothing to put into the bank.
I was aware of all these things for decades as I’ve been reading a lot of general science articles for decades and superconductors have been popular science for decades. Given all my knowledge about the state of superconductor R&D and applications that would benefit from the holy grail represented by a cheap, ductile, room temperature superconductor that doesn’t stop superconducting in high magnetic fields and high current loads, I cannot for the life of me envision any application or combination of applications that would raise living standards more and for more people than the industrial revolution. For that matter I don’t think it would be any more important than the transister and solid state electronics and probably much less so.