Ducting.. newbie needs help

Cooling Processors quietly

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maxxymus
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Ducting.. newbie needs help

Post by maxxymus » Sun Jan 18, 2004 3:04 pm

Hi guys

Wanted to know if there are any tutorials on ducting? More so... if I make a duct from the exhaust fans to the cpu then should the CPU fan be flipped? Currently it blows downwards on the HSF.. I have no idea how this ducting thing works.. please advise :)
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hyperslug
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Post by hyperslug » Sun Jan 18, 2004 3:21 pm

I tried this a little while ago. I used a Thermaltake ducting mod, pointed it at my rear exhaust fan and reversed the fan to pull air off the HS. CPU1 temps saw no gain or loss. CPU2 temps rose by perhaps 10C. Almost all HSF combo's have the fan pushing air rather than pulling for a reason. I have only heard of 1 exception in which pulling air was more effective and it was very particular conditions (certain fan, certain HS, etc). I'm too lazy to dig it up...

I should also add that I think in the Dell Precision Workstation line, there is a huge duct that encompasses both CPU's and pulls air off via 2 fans (80mm?). I'm sure Dell did their homework and found pulling air more effective in this case.

So in a bunch of words, I guess what i'm trying to say is I don't know heheheh
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Pjotor
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Post by Pjotor » Sun Jan 18, 2004 10:59 pm

One heatsink, which is better suited for a pulling fan, is the Alpha PAL8045.

Ducting is used for either 1) supplying the heatsink with cool air, or 2) draw hot (used) air away from the heatsink. The first is a little more tricky -- most cases have the air intake further away from the CPU, thus requiring a more elaborate duct -- but the second is often easy, because the CPU often sits close to the back of the case and therefore close to an exhaust spot.

Use 1) for a pushing heatsink fan, 2) for a pulling heatsink fan.
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HammerSandwich
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Post by HammerSandwich » Mon Jan 19, 2004 10:21 am

I believe ducting is the key to sucking air off the HSF successfully. Notice that Alphas have the aluminum shroud around the top of the pins, which forces air to run across more of each pin's length. You can experiment on other HSFs with masking tape to achieve the same effect.
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silvervarg
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Post by silvervarg » Tue Jan 20, 2004 3:02 am

If you want to do ducting the best way would be to start with a heatsink that is made for blowing air sideways. Many heatpipe based heatsinks work this way, so they are not that hard to find.
I would say that Aero Cool DP-102 is one great heatsink for ducting.
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