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Thermoelectric Generator With No Moving Parts
Savage-Rabbit writes "These guys have produced a working prototype of a thermoelectric generator. The thing uses extremely cold and hot liquids to achieve a heat transfer through a semiconducting material. This produces a voltage in the semiconductor who can produce up to 50-100 Watts which is actually enough for this thing to have practical uses. This generator could for example be useful in the chemical industry where many production processes generate a lot of excess heat that normally is simply lost. With a thermoelectric generator some of that lost energy could be recovered."
This is just a Peltier device in reverse. Instead of using a forced flow of electrons to drive heat from a cold surface to a warmer one, it is using the flow of heat from a warm surface, through the Peltier element, to a colder surface to drive electrons, generating current.
Actually the flow of heat from one body to another as the two move twords thermal equilibrium can be used to do work. In the device, heat is moving from an area of high tempurature, to one with a lower temperature, not the other way around.
I know lots of things. Most of them are wrong.
I wondered about this also. I think the SNAP generators that they have been using on space craft for years also us a Thermocouple. :)
Maybe these are cheaper/ better than average. Could they use them on the space stations to recover some energy from lost heat maybe?
I remember that they have used things like this in Russia for years. They use a flame on one side and the russian winter on the other
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It's a thermocouple if you use it to measure a temperature difference.
It's a Thermator if you use it to produce electrical power.
While not a major breakthrough, it's good to find more ways to use waste heat and up the efficiency of a system.
free ipod? yeah.
I assume you mean satellite, but anyway...
Yes, something like this is used in space all the time. RTG, SNAP, whatever you want to call it, heat from decaying radioactive fuel heats one end of a bank of thermocouples, and the heat bleeds off the other end, to generate electricity. Both manned, and unmanned have used them.
Doesn't anybody remember when the logic-impaired Greenpeace types were whining about Galileo, with its RTG?
Anyway, I just want to point out that, at least from the article, this sounds like another non-news thing. unless it's considered a big deal to use natural hot and cold water for the temperature gradient.
You got it right - they only use 50/4000 = about 1% efficient....for the heat they actually remove from the system
Also realize that they only made use of a small portion of the temperature drop. Assuming they had a cold sink of infinite (relatively) mass, they should get a temperature drop of approx 65 C, assuming a typical icelandic 10 C temperature. So take that ratio as well and they made use of only about 0.4% of the maximum Carnot efficiency.
However, carnot efficiency is capped as well - you can never get all the heat in the water - so then multiply by the carnot efficiency found from 75 C and 10C, which is 0.19. So now we're down to an absolute efficiency of about 0.06%. Not too good...
To get the absolute efficiency the easy way, take 50g/s of water, and multiply by the temperature of the hot source, and also by the heat capacity of the material. Then divide the actual power by that.
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