Quote:
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Originally Posted by Cathar
My thinking was as follows:
For the 300x240x29mm radiator I was personally approximating fairly close to a 10Pa drop at 3m^3/min, or for 160x160x25mm, around about 1.25m^3/min at 10Pa, or about 6.5Pa at 1m^3/min. So maybe 1.1m^3/min with the Papst.
C/W of air at 1.1m^3/min ~= 0.044
Bill's tests of the Thermochill 120.2 appear to imply a radiator efficiency in the very high 90's percent for air-flow rates of less than 1.0m^3/min and flow rates of at least 1gpm.
Assuming radiator efficiency of 90% @ 1.1m^3/min => C/W of 0.048-0.049
Ultimately it comes down to whether or not I was right with the 10Pa @ 3m^3/min assumption/extrapolation in the first place though. Core is thinner and less densely finned than the Thermochills, so I applied some extrapolation there to arrive at the large radiator's pressure drop by using Bill's PQ graph for the 120.2. Bill suggested 10Pa for the 120.2 at 1m^3/min. 2.5x the surface area immediately implies 2.5m^3/min at 10Pa, and I applied an arbitrary 20% bonus due to the more free-air flowing characteristics of this radiator.
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Agree with all.
Updated graph - gone the whole hog on PD (29mm v 50 mm thick) ie 5.8Pa @ 2.5m^3/min :
Edit :
Error in radiator simulations - so accustomed to water-flow sims, I, stupidly, shortcut calcs and assummed dP=k*Q^2.
Corrected graph:
