Re: Thermocouples

In article <12175.usenet@merckx.graphics.cornell.edu>,
PFEIFFER  <AE%SJSUVM1.BITNET@cmsa.Berkeley.EDU> wrote:
>Dave Hatunen says:
>> Again: thermocouples require two junctions, and the emf is a function
>> of the temperature differential between them. So if you already have a
>> source of higher temperature, then, with the other junction at ambient,
>> you can produce a small amount of energy. But if you do not have a
>> temperature differential, then thermocouples are useless.
>In many cases you have already temperature differentials.
>This is the nice thing with thermocouples
>Sources of surplus high temperatures you have for example in  the case of
>power stations or even by some solar applications let alone some
>industries as the steel industry. The question is the efficiency and especiall
>the costs per kWh.

Quite true. But I believe the original poster was under the impression
that somehow they generated an emf from only the one temperature.

Once you have a temperature differential there are all sorts of ways to
derive a little power; thermocouples are probably the worst choice
except under very singular circumstances.


    ********** DAVE HATUNEN (hatunen@netcom.com) **********
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