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Unread 06-26-2002, 05:19 PM   #23
Cova
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Join Date: May 2002
Location: Canada
Posts: 247
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Quote:
Originally posted by gmat
Cova you read my thoughts

Lemme explain the equations for the not math-savvy:

Q = U x A x delta T

Where

* Q = heat transfer rate, in BTU/hr or Watts or other power units
* When the system is at steady state, this equals the power output of the CPU. Neglecting ambient losses in the tubing and reservoir, Q is the same for the radiator as for the water block. It's just going in at one point and out at the other.
* U = heat transfer coefficient, in (BTU / hr ft² °F) or equivalent units. Barring fouling or a change in flow, this will remain constant. Note: it's a direct factor of flow...
* A = area, in square feet This is fixed by the heat exchanger design. To increase it, buy a bigger rad.
* delta T = difference between the temperature of the hot stuff and the temperature of the cool stuff.
* If the change in temperature of the cooling material is significant as it passes through the water block or rad, one should use a log-mean average for the temps in the subtraction.

I hope that settles it...
I may be reading your thoughts - but I still don't understand 3/4 of the equations you post up here.

Most everything that happens in our systems though can be figured out very simply. Our measurement tools are not accurate enough to determine a lot of these small variables in all the equasions, but if you keep basic physics in mind its very simple.
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