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Unread 09-14-2005, 05:09 PM   #17
duh_bing
Cooling Neophyte
 
Join Date: Dec 2004
Location: Singapore
Posts: 16
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joesgarage11:
the numbers i cal from your data doesn't make sense to me... it looks like your convective heat transfer coeff is ~30W/m2K that is way above the ~6W/m2K i cal for free convection. the energy equation -> Ein + Egen - Eout = Estored
look at the water loop system as a control volume
Ein - CPU (60W from AMD spec sheet)
Egen - pump (assume negligible compared to CPU)
Eout - Rad
Estor - Energy that is stored by the fluid with increase in temp. should be 0 at steady state. I suspect that your sys have not reached equilibrium when you did your measurements and thus a skewed result set.

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Just set up a passive loop with a 120.3, 6m of garden hose and a small res... took 2hrs to reach ~60CPU ~45H2O ~29Ambient at full load (running dual prime95, an mpeg convertor software and rise of nations) might still go up but then i had a breeze

The rad was place vertically against an open window. Will repeat the experiment horizontally tomorrow night. need to sleep its 6am in the morning here... hee... leaving the sys to run to see if temps will get any higher w the noon sun.
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mwolfman:
as mentioned above, i will try the horizontal orientation once i get my 1 day data. I think i shd get the same sort of results as yours. Can't expect the winds to favour me all the time ya?
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will post some pics of the temp setup when i wake up... good morning! zzzzZZZ

Last edited by duh_bing; 09-14-2005 at 05:20 PM.
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