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Radiator airflow using negative pressure

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johan851

Insatiably Malcontent, Senior Member
Joined
Jul 24, 2002
Location
Seattle, WA
I posted this at SPCR first, but didn't any responses. I thought I'd give you guys a try!

I've been thinking about changing my case for a while (and possibly ditching watercooling). Right now I have a SLK3000B with an MG Metro (car) radiator bolted to the side. There are three low speed Yate Loons at about 7v on the radiator and another two inside the case. The (extremely loud) hard drives became less annoying when I soft mounted them, but the case is still a little loud. The biggest hassle is trying to move the thing around - it's very heavy and awkward, and all of the exposed radiator fins are a bit fragile.

I was thinking of moving to mATX and going to air, but I also liked the looks of the Antec 300, which has almost exactly the same dimensions as the case I have. I hesitate going to air cooling because I like my overclocking, and it's hard to resist the urge to tweak. And I know watercooling can be quieter.

I figured a 2x120mm radiator might fit in the front of the Antec 300, and I found a person who has done this rather nicely: http://www.techpowerup.com/gallery/details.php?id=2124

The problem with radiators is always the pressure needed to push air through them as well as the fan hubs and other dead spots. The real question of this post is this: do you think an Antec 300 with a quiet 120mm and 140mm fan at the top rear would provide enough negative pressure to pull air through a radiator at the front, assuming the rest of the case is sealed? Would that be a quiet setup?
 

Spawn-Inc

Member
Joined
Jun 13, 2007
if you can get the case properly sealed, it should work,

for a rad i would get the lowest fpi rad out, which i believe is as low as 8. XSPC RX, black ice SR-1 and thermochill are the lowest.

you could always try your way and add low speed fans as you go.



is your computer on your shoulder next to your ears? i don't understand how people say hdd's are loud. i have an SSD and i can't hear a thing :) but seriously my standard hdd's are quiet.
 

Moto7451

Senior Something
Joined
Feb 24, 2004
Location
LA, CA
Yes it'll work. I've done this many times in the past.

My current build is the first one with fans in the push configuration. You really don't need that much pressure to pull air through a radiator (Axial fans don't really put out much pressure anyways, blowers are better for that) and so long as the fan is sitting flush with, or has a flush fitting shroud, it'll work just fine. For a while I just bolted the fans directly to the rad (pulling air through) and it was fine.
 
OP
johan851

johan851

Insatiably Malcontent, Senior Member
Joined
Jul 24, 2002
Location
Seattle, WA
for a rad i would get the lowest fpi rad out, which i believe is as low as 8. XSPC RX, black ice SR-1 and thermochill are the lowest.
Looking at the radiator sticky, it seems the Swiftech MCR220 is the one with 8 FPI. Would that be enough surface area to do better than air?

My current build is the first one with fans in the push configuration. You really don't need that much pressure to pull air through a radiator (Axial fans don't really put out much pressure anyways, blowers are better for that) and so long as the fan is sitting flush with, or has a flush fitting shroud, it'll work just fine. For a while I just bolted the fans directly to the rad (pulling air through) and it was fine.
Maybe you don't quite understand what I mean. I don't want to suck air through the radiators with fans mounted on the radiator (that's how I usually do it), I want to seal the entire case, put a radiator at the front, and use negative pressure from case fans in the back to provide airflow.
 

atomic ferret

Member
Joined
Nov 5, 2005
It would work if you absolutely sealed the case.

Are you really bothered by low speed Yate's at 7v? Those are pretty silent. It would be very beneficial to use some very quiet/undervolted fans than none at all.
 
OP
johan851

johan851

Insatiably Malcontent, Senior Member
Joined
Jul 24, 2002
Location
Seattle, WA
Are you really bothered by low speed Yate's at 7v? Those are pretty silent. It would be very beneficial to use some very quiet/undervolted fans than none at all.
I could handle putting a couple of 5v Yate Loons or other fans on the radiator, I suppose. I figured that between the 120mm, 140mm, and PSU outtake fans, combined with the fact that there are no dead hubs on the radiator, might produce a little more air overall. And not having fans near the restriction of the radiator would make everything quieter.

I guess I just want to see what's possible here. We always talk about how much quieter water can be than air while still performing well, and I want to see if I can pull that off in a simple, compact setup.
 

oldbrave

Member
Joined
Apr 8, 2009
Location
Sacramento,Ca.
If you were to take and hog out a couple of 120x25 or better yet 120x38's and place them between the lowspeed fans and the rad in a pull through setup, I think you'd find that this would increase the efficiency by a factor of 2 at least and would even be quieter.
 
OP
johan851

johan851

Insatiably Malcontent, Senior Member
Joined
Jul 24, 2002
Location
Seattle, WA
If you were to take and hog out a couple of 120x25 or better yet 120x38's and place them between the lowspeed fans and the rad in a pull through setup, I think you'd find that this would increase the efficiency by a factor of 2 at least and would even be quieter.
Well, I know I could use a shroud. What I want to do is use the CASE as a shroud. But it looks like no one has tried this before, so maybe I should just give it a shot. :)
 

muddocktor

Retired
Joined
Nov 1, 2001
Location
New Iberia, LA
Yeah, give it a whirl and let us know how it works out, johan. But I imagine it will be hard to seal up the front of the case around the optical drive adequately.
 
OP
johan851

johan851

Insatiably Malcontent, Senior Member
Joined
Jul 24, 2002
Location
Seattle, WA
Yeah, the optical drive area is always sort of complex. We'll see how it goes.