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Ohio Researchers Advance Heat Reclamation Technologies
Downchuck writes "Researchers at Ohio State University claim to have synthesized a new material capable of delivering electricity directly from heat, at an efficiency far better than existing thermoelectric materials. Scott at ArsTechnica has an interesting take: 'Merge this with the new MIT solar dish and you're in business!'"
But I like this better.
What?
Finally, we have a truly renewable source of energy - we can just harness all the hot air coming from our politicians.
It's not possible to make electricity directly from heat. It is possible to make it from a difference in heat between two points.
Bruce Perens.
Could it be used to get more power out of a nuclear power plant?
You just got troll'd!
And since I can't make hyperlinks correctly on slashdot, I'll try again: thallium.
Nasty stuff, as its compounds are very easily absorbed through potassium uptake pathways in your body, but behave very, very differently from potassium. I seem to remember a chemist friend telling me that if you deal with thallium, you practically need an entirely separate lab for it.
"We are Microsoft. You shall be assimilated. Competition is futile."
That material reach its peak at 950F (~500C). Not sure if MIT approach will worth combining with this as maybe the area needed could make electricity by other means.
But there are a lot of areas where heat is produced, and some of this could be used to get extra electricity.
Maybe the most important point, at what cost? how rare/expensive is that new material? If is very, maybe the main use would be not for our normal lifes, but maybe for i.e. space probes.
From the article: "the material is most effective between 450 and 950 Fahrenheit" So simply plug this into a geothermal source, instant energy solution until Earth's core freezes.
This allows better RTGs, but they would only be marginally efficient for, say, reclaiming computer case waste heat. This is especially so as you can't put them on the CPU directly, where the differential is great, because they are insulating as well. You will need to put it at the radiating end, over a large surface.
Thallium accumulates in your testicles. I remember hearing stories about labs handling thallium where only women were allowed.
The article at the Green Car Congress site titled New Approach to Developing Thermoelectric Materials Doubles Efficiency" has a lot more scientific details than that article linked from the summary, especially on the actual formula that determines "zT", which is the thermoelectric conversion efficiency coefficient:
And also detailed nanomaterials engineering analysis of the quantum structure of the quantum chemistry's thermoelectric effects.
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make install -not war
... contain a link to a possibly more useful article with some more comprehensible numbers:
http://www.technologyreview.com/Energy/21125/
e.g. The device could increase fuel efficiency of vehicles by approximately 10 percent.
Even though that article linked from the summary says that typical engines in cars get about 25% of the gasoline's energy content into car motion, it's actually about 20%. That's a lot of wasted energy: about 4:1 waste:use.
But lots of combined cycle plants (like CCGT gas turbines) reclaim a lot of their waste heat into more power. Taking a maximum mechanical power extraction of 60% of the gas' energy up to 85% by heating steam, which is an additional 25% of the original mechanical power.
CCGT reclamation tech is probably not practical for vehicles, so this new material is a welcome advance. Especially if the researchers get the zT from its new 1.5 high to its predicted 3.0 or so. But in fact DARPA has funded Trinh Vo at Lawrence Livermore National Labs to grow nanowires that already have a zT at 3.
More of that kind of material research is very welcome, because at zT 3, these materials can replace freon refrigerators with the same electrical efficiency. Since freon refrigerators require lots of energy to build, and then to recycle, replacing them with a simple material that can scale to any size (including very small, as in microelectronics), means a vast sector of modern industry, including transportation, could switch. If making the material is less energy intensive, and less reliant on a limited critical resource than the freon refrigerators or the CCGT reclamation systems, global energy efficiency could take a giant leap.
A leap that could be just around the corner, in Ohio.
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make install -not war
What's this power efficiency rating? How much is 1.5 in God's honest Watts per Kelvin, or a simple percentage of power in/power out?
Just attach a generator to the lower jaws to my husband and his mother. The energy they produce by moaning about the heat should cool the whole of Cologne for the summer.
-- Put crudely, the world is an extremely large problem instance. (Russel/Norvig Artificial Intelligence)
An achievement made up of toxic elements, the first being rat poison, the last being the rarest there is. Chances are this won't be cheap to make nor to dispose of, and I wonder what hazards it would pose to the environment if released (vehicles do crash or get abandoned from time to time).
Use power to shift heat or generate power from heat flow.
Engineering is the art of compromise.
It's doped with thallium, that means that the thallium is imbedded in the metal alloy. I don't think it's going anywhere.
z is related to the Seebeck coeff (which tells you how much voltage a given delta-temp gives you in a material), the resistivity and thermal conductivity. It is multiplied by T (the average temp at which the performance is measured) to give a non-dimensional number.
zT doesn't tell you the efficiency because that would depend on the delta T (next para), but it is roughly proportional to it for given operating conditions. zT = 1 materials have efficiency maybe around 5% under best conditions, for zt = 3 you might be around 20%. Notice that if you know S and delta T you know the voltage: you can do some simple circuit calcs with a matched impedance and get the power it will generate. Compare that to the heat energy you get from the delta T and the thermal conductivity and you can get an efficiency, but instead of that lets just throw out some round numbers.
Remember efficiency depends on the delta T due to the 2nd law of thermodyamics. The smaller delta T is the lower the max theoretical efficiency is. If the engine exhaust is at lets say 500F the max efficiency any device could get would be 1 - (492 + 72)/(492 + 500) = 43%. So that would be 78kW of your 180kW for a thermodynamically perfect device.
So if you can get maybe 20% out of thermoelectrics under the best conditions, the low-temp engine exhaust scenario would probably mean you could get at best 10%. So 20kW or so I'd guess. Once you design an actual system it would probably be more like 5 or 10kW.
Equine Mammals Are Considerably Smaller
Johnson Thermoelectric Energy Conversion System? Seriously, this one is being developed to operate at lower temps. I wonder if this new one will work better or not? But it sure would be useful to add one (or both) of these to say power plants to absorb some of the heat and continue generating more electricity.
I prefer the "u" in honour as it seems to be missing these days.