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Originally Posted by prandtl
Butcher
Your Qtot are way overestimated, using Since87's pelt calculation excel sheet, i got a Qtot (using 100W from cpu) of 315W, instead of 401W. I also have the feeling that the estimated Q of the cpu is also overestimate, but I have no idea by how much.
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The stated power draw of the TEC is 300W (straight off the manufacturers specs - 25A@12V = 300W). Add 100W of load to this... 300+100 = 400W, not 315W. It's not exactly a hard calculation. I'm more inclined to trust this very simple and proven formula (ohm's law is pretty much known to work) than a random spreadsheet.
Q of the cpu is an estimate, however the stated power output for a P4c at 2.8GHz is 70W (sorry, misread the data sheet slightly and got 75, still not far off even so). (source:
intel processor data sheet). I adjusted using the forumula Q = Qspec * (f/fspec). So Q = 75 * (3500/2800) = 93.75W - should be 70 * (3500/2800) = 87.5. Note however that this assumes stock voltage - increasing voltage causes a very large power rise. Also note that the rated power for a P4c 3.4GHz chip from intel is 89W so my estimate might be a little low.
I'm not sure what Since87's sheet is based upon, but without knowing I'm not likely to trust his results over ohm's law and intel specifications.
