t213646

I'm getting two PA120.2 radiators and was going to mount them next to each other so air goes through one and right into the other. I have about 8" of width in the case to do this in, and minus the width of the rads - 2*60mm or so - this leaves me with a little over 80mm for fans. I was wondering whether I'd get better performance with six 120x25mm fans arranged like so

fan>rad1>fan>rad2>fan

or four 120x38mm fans on the outside

fan>rad1>rad2>fan

I imagine that the six 120x25 fans would be better but I'm just checking.

MSPAINT diagram for people who have no idea what I'm talking about is attached.

Bonus question: will feeding the second rad "hot" air directly from the first lead to any significant performance drops?

Attached Thumbnails

 

Meecrob

00000000000

razar

Depends on the type of fans, CFM etc....
If CFM was equal between the 2 fan types (38vs25) its logical that the 1st scenario would produce more air flow.

What types of fans are you considering?

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t213646

Probably something in the 70-80CFM range for either as that seems to be the cutoff for reasonable noise levels. It sounds like six 120x25 fans is indeed the way to go unless there's a 120x38 that has substantially higher flow at under ~35 decibels.

razar

Bonus Answer......
Feed the rad on the "hot side" first then it flows to the one on the "cool side" then back out to the loop.

The temp difference between the 2 rads would then be negligible

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nategr8ns

First of all, always have the fans blow up. General rule of temperature: Heat goes up by itself, so don't fight it with fans blowing down.

I'm not really sure what the performance increase will be, but it won't be nearly as good as two radiators next to each other instead of on top of each other.

Do you mind having an external radiator somewhere? or would you rather it be internal?
Also, fill out your PC specs in your User CP. Links at top of page

EDIT: Yeah, the guy above me has a great idea! Never thought of that

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t213646

Awesome, thanks. rep+

E: @nate, this is internal because it's prettier that way it essentially has to be mounted sideways because of the case configuration - vents are on the sides.

DuckieHo

I would never do that. Yes, you will experience a significant performance drop. 100% of the heat expelled from Rad 1 is going to Rad2.


Heat does not always go up.

Heat will always move to cooler areas. In conduction, if the cooler area is below... then the heat will move there. In convection, the hotter fluid will move to the cooler/less dense fluid (which is only generally up).

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t213646

In that case, I could go with one PA120.3 and save some money. I'm a little worried about clearance with the PSU (trying to fit all this in the bottom of a silverstone tj07 with reasonable room for airflow) but I think only half an inch or so of the rad would be behind it.

razar

I figured you were dead set on 2 120's due to configuration....a 120.3 would be better

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