Fan location and HSF direction

[mickey928]

Hi everyone,

I am planning on a major upgrade. My only question is the airflow inside the case. I did my research and found positive and negative pressure, i am gunning for negative to lessen the dust from comming in. So to achieve this i need more intake fan than the exhaust. Knowing this the problem arise, where should i place my fans.

Case fan location:
Front (bottom) - 2 x 120-140mm
Rear - 1 x 120mm
Top - 2 x 120mm

Scenenario 1: 3 x 120mm static pressure intake (2 on top and 1 at the back) and 2 x 140mm airflow exhaust. Basic science states that hot air goes up, so i am a concerned if the exhaust will blow the hot air out from its position (lower front panel). And my HSF btw will blow air to the front as well, will my RAM suffer due to the excess heat blown toward them?

Scenario 2: 2 x 140mm front and 1 x 120mm rear static pressure intakes while the top is 2 x 120mm airflow exhaust. The problem here is where will my HSF blow the hot air from the procie? To the front?

Scenario 3: 2 x 140mm static pressure intake, top and rear are 3 x 120mm also static pressure exhaust with a lower rpm. HSF towards the rear exhaust.


Which scenario will hinder dust from comming in and expel hot air out effectively.

Thanks guys.

 

[huvik]

put 2 140 mm on the front as intake and 1 120mm on the rear as exhaust.

 

[Spectre694]

You've got them backwards you want positive pressure.

Positive = more air pressure in case then air/dust moves out of cracks/vents etc. in case
negative = less air pressure in case sucks air/dust in through all the cracks/vents in the case

Airflow in PC cases should typically be front/bottom intakes and top/back exhaust.

 

[thor220]

Case fans shouldn't be static pressure. Static pressure fans are designed to move air through heatsinks and radiators, not case vents. You'll cripple you airflow if you use Static pressure fans. Just go with airflow fans.

 

[mickey928]

So all fans should be airflow, so if i configure the fans like this 2 front intake and 3 exhaust there will be more air comming out of the case, as a result air from outside will be pulled ibside thus inviting dust to come in. I am really confused. Lol.

 

[Spectre694]

So all fans should be airflow, so if i configure the fans like this 2 front intake and 3 exhaust there will be more air comming out of the case, as a result air from outside will be pulled ibside thus inviting dust to come in. I am really confused. Lol.

You don't have to use a fan in every single slot most systems are okay with two or three fans

 

[mickey928]

The case i will buy has a psu and hdd shroud. The clearance between the lower front intake is about 3-5 inches. Thats the reason i want a static pressure as intakes. But if it wont matter i will get the aiflow instead.

Is an extremely positive pressured (4 in and 1 out) case good?

 

[Spectre694]

The case i will buy has a psu and hdd shroud. The clearance between the lower front intake is about 3-5 inches. Thats the reason i want a static pressure as intakes. But if it wont matter i will get the aiflow instead.

Is an extremely positive pressured (4 in and 1 out) case good?

Not really the key here is airflow. Just put two in the front and one in the back. Then see if you need any more (doubt it)

 

[thor220]

The case i will buy has a psu and hdd shroud. The clearance between the lower front intake is about 3-5 inches. Thats the reason i want a static pressure as intakes. But if it wont matter i will get the aiflow instead.

Is an extremely positive pressured (4 in and 1 out) case good?

It's more important that you make sure that air can flow properly. Hot air rises and should move from the front of the case to the back. Make sure that none of your fan's airflow run into each other.

The front fans should always be intake, the rear fans should always be exhaust, bottom fans should always be intake, top fans should be exhaust, and side door fans should always be intake and slow.

 

[mickey928]

one last thing. is it alright to choose a low noise case fan which spins slower? or do need a specific rpm to circulate air effectively inside?

 

[thor220]

one last thing. is it alright to choose a low noise case fan which spins slower? or do need a specific rpm to circulate air effectively inside?

It would be completely fine to put a low noise fan on the top, bottom, or side of the case but from the front and back you preferably want a higher RPM fan. It's possible to get the best of both worlds by installing PWM fans that can change thier speed based on CPU temp. They'd only run full speed when the CPU is hot.