One fan in, four out. Consequences?

JonJ678

JonJ678

JonJ678

Soldato
Joined
22 Dec 2008
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Location
England
Hey. I'm trying to decide between two options for airflow in my case.

I'm inclined to go with
Two fans on a 120 radiator, intake, bottom front of case
One fan on a 120 radiator, exhaust, rear of case
PSU, exhaust, top rear of case
Two fans on a 240 radiator, exhaust, top of case, at the front

The issue here is that there are few (aiming for zero) holes for air to be drawn in through. I don't know what the effect of this will be, anyone more experienced care to guess?

Its convenient in terms of preventing dust getting in. The other obvious option is to reverse the fans on the top, which will make maintenance harder, or to leave some holes in the case for air to get in through near the top of the front of the case. Hopefully I've been clear enough, photos will turn up in the future if need be. Cheers

Done my best with test runs, but it's tricky without installing components in the case. With radiators and fans installed, with the negative pressure set up, lots of cold air comes out the top. This is without psu and the pci covers removed, so it's likely that air is moving in through these. I guess I'm hoping that fan rad fan moves air through the radiator significantly faster than one fan per rad.
 
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I wouldn't think so as the case can drew air in from vents and stuff in the case still best to have more than one intake through.
 
Your case will crumple up like a tin can if theres no intake . . . :D

Nah, I prefer slight negative pressure, it helps the airflow, if there are NO other air holes than the intake fan, then all the other fans will be working hard, so will have a reduced lifespan (Could lose a year over 20, or whatever, I have no idea!). More prone to failure.
 
Doesn't have any vents at all, so no luck there. The two stacked 120mm fans are the only intake.
Current thoughts are that I'm probably going to have to test it to find out, but I'd still like to hear opinions from people here. Venting the optical bays might be the answer I end up with. Seems to be a lot less space in my case now that there are radiators inside it.

Bit confused by that PhillyDee, one intake and three exhaust suggests the three need to work only a third as hard. Pumps don't work like that though, so I can believe the exhaust fans will run hotter and fail sooner. Voltage control might be an answer
 
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I found a scythe kama bay to be a great addition to my akasa eclipse, currently running 2 front intakes and a single exhaust fan.

Picture535.jpg
 
I'm not sure I have enough space for one as far as depth goes, will need to measure some things. Was fitting it any hassle? Out of the four optical bays I'm only using the lowest one, so a kama bay in the top three would lead to a pleasing symmetry

Cheers for the photo :)
 
It was extremely easy to fit mate, only needs to be screwed into the drive bay holes closest to the front of the case, depth wise its only about an inch or so deep.
 
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If you have 4 fans, all 20cfm, then you have 60cfm out, and 20 cfm in. The other 40 has to come from somewhere, so its either going to suck it through the only intake (the intake fan, which will have to spin faster) or if the intake fan is 'tougher' then it will slow down the outtake fans and create load. Of course, this assumes the whole thing is sealed and there is no gap around the fan blades. In reality, there are gaps around the fan, and it will decrease their efficiency, and add extra load. It may also increase the noise!
 
Slept on the idea, and am pretty much sold on the kama bay being the solution. Either that or a diy effort similar to one.

Cheers PhillyDee, that's quite clear. All the fans are nominally identical, so the intake is going to suffer from this arrangement at the moment. Push pull on the intake radiator, one fan on each of the 3 exhaust radiators, and a kama bay in the optical bays looks reasonable.
 
From what I've always heard it's better to have high pressure inside the case. ie more intake fans then exhaust fans. It helps force the air through the case faster which allows for better heat conduction.
 
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