Radiator + fan config

Locky

Locky

Locky

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ok which way do you guys have your fans, i read mixed reports.

pull or push config?

thermochill pa120.2
 
Hi TiZor

On my rig i have the fans pushing air over my rad as it is externally mounted on top of my case with a 3.5 inch gap to allow air flow over and under.

If the radiator is installed via the top of the case ie internal some users have the fans pushing to circumvent air around the case internally and others use pulling to remove any excess heat from case. As to the thermo chill i am unsure as i do not use this particular radiator, Im sure the principle applies. Is your radiator internal or external mount? Other water coolers who use the thermochill radiator will add further to your post im sure
 
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It used to be that Pull Pull was best (second fan helped with pressure on older restrictive rad). I use fans in a pull direction.

And now it seems push is quieter. In reality it make little difference.
 
I'll just repost what I posted to similar question on a diff site... note, this is in direct relation to ThermoChill rads... it may not apply to anyone elses.

"Minimal difference" (or "little difference" as weescott put it) is a term used a lot for push vs pull. Realistically, in radiator performance terms that 1 degree is a HUGE amount of difference when you're talking temp changes in the regions of hundredths of a degree per watt of heat, which means that the setup with 1 degree colder temps could be able to remove up to an extra 50watts of heatload (if asked to) over the warmer setup. How important this is to you depends how close your radiator is to it's limit for the airflow your fans can provide in either config.

Pull (suck) provides more even airflow which generally results in better performance over the same fan on the same radiator in push...

Will also compare shrouded, unshrouded, suck (pull), and blow (push) air-flows.

Was just messing with the equipment a bit last night, putting a Yate-Loon on a PA120.1 radiator with a shroud, in suck or blow arrangement. I was able to position the anemometer on the other side of the radiator to get an idea of the evenness of the air-flow through the radiator. Used the tachometer to measure the fan speeds, and the noise meter the fan noise levels. I haven't calibrated the fan noise levels yet to any base reference point, so I won't report the absolute values I got, just the relative values.

Free-air: +0dBA noise, 1480rpm speed
Shroud Suck: -2.7dBA noise (i.e. quieter), 1350rpm speed
Shroud Blow: -3.0dBA noise (i.e. quieter), 1460rpm speed

I found the noise level differences, and the fan speed differences to be quite intriguing. If the fan is spinning faster, it's pushing more air-flow in the blow-mode.

However, using the anemometer on the other side found that with the shroud, in blow mode, the air coming out the edges of the radiator had about an 80% higher velocity than the air coming out the dead-center. In suck mode, the overall air-velocity appeared lower (will need to measure properly later on full-testbed), but it was more even, with only about a 25% variation between the edges (higher) and the dead-center (lower).

So yeah - this throws a cloud over the general suck/blow debate. The fan appears to like to blow much better than to suck, but the air-flow is less even, even though it's of a higher velocity. The fan is also quieter in blow-mode.

It would appear (without further testing) that putting a fan into blow-mode on a radiator with a really deep shroud (60cm) to straighten out the air-flow would be the best way to go, but that's not terribly practical.

*snip*

It seems to be a scenario of while blow creates more air-flow, the unevenness of the flow through the core hurts performance. Performance does not scale linearly with air-flow, and so it's always better to have even air-flow over the entire core area, rather than some areas receiving twice the air-velocity of other areas.
Click to expand...

Source: http://www.xtremesystems.org/forums/showthread.php?t=150261&highlight=fan-pull
 
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