Hi! I built my first computer over the summer and thinking of adding more fans. But I'm really bad with science and getting confused with all the airflow diagrams on the net, so I could use your help here to point me in the right direction.
So this is my case:
The blue circle is the 92mm exhaust fan, rated 46 CFM.
The red circle is empty now, but there's space for a 120mm fan.
QUESTION 1: My main goal is to limit dust in the case. So from what I've read, the 120mm fan in the front of the case should be an intake fan rated with a CFM higher than the rear fan? And how much higher than 46CFM should it be to be effective?
Meanwhile, this is the side of the case which has a side air duct:
QUESTION 2: I can remove it and replace it with an 80mm fan, but the salesguy said that wouldn't really make any difference. Since my case is pretty basic and doesn't get hot, are there any major benefits to having the 80mm fan, or should I just forget about it and keep the air duct?
It seems like you'd just like to fiddle with your computer. For dust u can take off the side panel and use compressed air on. a 120MM fan is probably not needed. Just check the temp on your CPU, if they don't get hot then u don't even need to bother with adding fans. If you really want to you can add a 120MM front intake fan with a fan filter And put a 80MM side intake fan with a filter.
Also the reason to have more CFM in intake is to create a postive pressure, which means its trying to bring in more air than it can put out. If it's negatively pressured(more exhaust fans)t will start sucking air from any where it can get it. Fan grills,CD roms cracks... anywhere. Simply put, air doesn't come from nowhere. So having all exhaust fans, will mean they're useless or if they're working its because they're pulling air from holes in the case. Try taking a straw putting your finger over it then sucking on it. That's what happens when you use all exhaust fans. Same thing would happen if you tried to blow on the straw of course, so you'll need to find a balance, with more preference in more intake. Note, even with filters, your case will still get some dust in it over time. Good luck.
If you don't have an issue with temperatures inside the case, and your only goal is limiting dust, maintaining positive pressure can do that, however you've got to have a pretty airtight case. Any mesh openings that are not covered with a fan, will preclude you from controlling the pressure in the case. Your best bet is to invest in some canned air :-)
Put the 120 mm fan in the bottom, if you want and average fan I use Xigmatek and if you want one of the best buy a Cougar fan. See it that helps. If you are concerned about GPU cooling, by all means, mod the side panel with an 80 mm fan (intake).
this is a antec case so put a 120 mm in front also if you could fit a 120 mm in back go for it you could also add the 80 mm to the side panel that gone give you more fresh air to the cpu and it's surround,that your graphic card we see at the lower bracket