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Unread 11-08-2004, 02:49
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Re: Cold Electricity?

Thermo Electric Modules ( Pell Cells ) are pretty neat but are really only very useful in certain applications, and have to be designed specifically for it.

A Thermo Electric Module in ideal conditions ( with correct voltage amperage blah blah blah ) will be roughly 40 degrees centigrade cooler than the hot side. Now of course this is what it should be but there are many x factors that can bring this down. ( Ie fluxuation in voltage and not properly connected ) Which makes it useful, but usually only in certain applications, because you typically need to try to keep the hot side cool . The cooler the hotside, the cooler the cold obviously.

Another thing is that a thermo electric module can only peak about about 140 btu's of cooling,which is somewhat a small amount, if you consider 1lb of ice has 143.3 btus of stored cooling energy in it, And then it takes a .48 btu's to raise it each degree F which I believe is close to about 1btu per degree c.

But for this application acting as a chiller with not too much other involvement if your boys want to use thermo electric modules just to chill it should work well atleast well enough. As long as they design the packaging correctly and make sure that none of the dispensed heat re-enters the cooling package and dispensed into the atmospher then your ambient temperature could actually do the cooling. I mean your not asking for the thermo electric modules to cool the liquid .. just to keep it cold. Again it could perform fine if designed correctly. Plus, for as long as it would keep it cold, it prob. would be killed off before the effects of the chiller began to digress :-P.

Main problem with most heat sink designs is lack of common sense and double checking things. People fly by with the calculations then design things that completely screw up everything they already figured out. Of course it happens in all kinds of engineering.. but you see it soo much commercial style heatsink product.

As for FIRST applications of thermo electric modules, i doubt you'll see them incorporated. One they drain more battery life, 2 they are hard to adapt to the units you'll need them on. The work put into them and the benefit produced is likely to be in great disfavor. I tends to work better if you are worried about cooling a motor by more effecient power management and maybe bonded fins with a muffin fan. We had custom designed heatsinks by the heatsink company I work for now ( as a psuedo intern/lab rat ) and the amount of work put into them/ over benefit recieved was very disfavorable. So its all where you find your nitch as far as FIRST goes.

Dan
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