IM confused about intake and exhaust..?

[Dasher]

Okay well arent they like the same ill make a case with X;s to show u what i mean

" I " means intake fan

"E" Exhaust

xxxxxxxxxxxEEEEEEEEExxxxxx
x x
x x
x x
x x
x x
x x
x I
x I
x I
x I
x I
xxxxxxxxxxxxxxxxxxxxxxxxxxx

i think my case is meessed up

anyway

Okay so the front of ur case as an intake fan that gets the cool air

and the top has exhaust that makes the heat go out...

well wouldnt they do the same thing since one is sucking in cool air wouldnt the top also be sucking in cool air and not repeling hot air out?

 

[zodiacfml]

i agree. from experience, it seems having exhaust fans is enough.
you'll only want an intake if you want to blow fresh air on the devices like hard disks, but they don't seem need it too,i'll suggest disabling the intake fans if you want the system run a little quieter.

 

[croc]

A basic law of thermodynamics... Heat rises. Normally, your front fan is mounted down towards the bottom of your case (a generalization, as you didn't mention case make, model...) and top mounted fans are, well, at the top. So reversing the flow of these fans would be contra-flow to a basic law of physics. However, feel free to try your own experiment...

Some cases also have side-mounted fans, and others also have extra fan locations in the upper portion of the case, mounted towards the rear. I would normally recommend that rear mounted fans also be used as exhausts, and side mounted as intakes.

Filtering your intakes will help keep the dust down inside your case as well, just make sure that your filter is free-flowing. Panty hose is not a great filter, but better than nothing. Some recommend coffee filters, but hold one up and breathe through one....

 

[Dasher]

OKay so heres my question...

this is my case

http://www.newegg.com/Product/Product.aspx?Item=N82E16811133056

at the pictures in the 2nd row 2nd from last(third from first)

you see they have 2 extra HDs u can remove them and put 2x 140mm or 120mm fans would those make a diffrence in airflow if i added two? Also theirs a 140mm fan in the front and a HD cage behind it

would it be possible for me to remove the HD cage and use a 5.25 to 3.5 converter and put my HD in it? therefor increases the amount of cold air coming in since the HD cage wont be blocking it

also this is a noob queestion but what do fan brackets do? do they just protect ur fans?

 

[V3NOM]

you can have a fan pointing such that it blows air in or sucks it out. that simple.

 

[croc]

OKay so heres my question...

this is my case

http://www.newegg.com/Product/Product.aspx?Item=N82E16811133056

at the pictures in the 2nd row 2nd from last(third from first)

you see they have 2 extra HDs u can remove them and put 2x 140mm or 120mm fans would those make a diffrence in airflow if i added two? Also theirs a 140mm fan in the front and a HD cage behind it

would it be possible for me to remove the HD cage and use a 5.25 to 3.5 converter and put my HD in it? therefor increases the amount of cold air coming in since the HD cage wont be blocking it

also this is a noob queestion but what do fan brackets do? do they just protect ur fans?

Ok, now we are getting into some laws of fluid dynamics... A bit more complicated, but it can be boiled down to 'slightly more CFM intake than exhaust is good...' Positive pressure ventilation, keeps the case cracks blowing out, not sucking dust in. A lot more intake than exhaust, however, just keeps your intakes from performing at a good effeciency. A lot more exhaust than intake runs just the opposite, as you'd expect Negative case pressure...

May have to do some research here on the CFM rating of your various fans to find out. CFM ratings are directly additive, (mostly) which makes it easier.

 

[V3NOM]

errrrrr no.

negative air pressure is beneficial, as otherwise, the air will be milling around the case, creating hot air pockets. negative air pressure onthe other hand sucks in air from all the small holes in the case, making virtually no hot air pockets. i have yet to see a real techy advise anything BUT NEGATIVE AIR PRESSURE

 

[croc]

errrrrr no.

negative air pressure is beneficial, as otherwise, the air will be milling around the case, creating hot air pockets. negative air pressure onthe other hand sucks in air from all the small holes in the case, making virtually no hot air pockets. i have yet to see a real techy advise anything BUT NEGATIVE AIR PRESSURE

Then neither you nor your techie friends have designed / built data centers. If my case was that badly sealed, I'd either improve the seals (if I really like the rest of the design) or chuck it out and find a better case.

Go ask some of your techies (or feel free to chime in yourself) how to design a center for an HP superdome. And that's older tech these days.

 

[zodiacfml]

you're both right but what we need is efficiency to avoid too much fans and noise,the motherboard needs the cooling most because it does not last long when capacitors heats often.
i have experimented with lots of configurations of intakes and exhausts and discovered that the basic of case cooling is adequate exhaust, even it had a lot or no intake fans. if there's little exhaust and more intakes, the whole case becomes warm heating the motherboard.
i made a system with a processor fan ran in reverse so that it pulls air from the heatsink and exhaust at the side of the case. i discovered that it only decreases cooling on the CPU by 1 to 2 degree celsius while a 5 degree drop in motherboard temps, so, no need for another exhaust or intake fans.

yet, i still suggest an intake for fast, multiple hard drives.

 

[croc]

you're both right but what we need is efficiency to avoid too much fans and noise,the motherboard needs the cooling most because it does not last long when capacitors heats often.
i have experimented with lots of configurations of intakes and exhausts and discovered that the basic of case cooling is adequate exhaust, even it had a lot or no intake fans. if there's little exhaust and more intakes, the whole case becomes warm heating the motherboard.
i made a system with a processor fan ran in reverse so that it pulls air from the heatsink and exhaust at the side of the case. i discovered that it only decreases cooling on the CPU by 1 to 2 degree celsius while a 5 degree drop in motherboard temps, so, no need for another exhaust or intake fans.

yet, i still suggest an intake for fast, multiple hard drives.

No argument from me, up to a point. Many of the newer 120 mm fans deliver excellent flows at lower RPS's these days as fan designs are improved. Generally, a 50CFM fan in general will be quieter at a lower operating speed than a 50 CFM at a higher rated speed (made up #'s, BTW). But with some of the newer fan designs... I am amazed at some of the CFM ratings / RPM operating speed. And I agree, hot high speed drives really need their own fan blowing on them. Try cooling cheetahs... Mine sit in an external case, in an un-used closet, with the equivalent of a large-ish house fan blowing on them... As to your HSF test, I really like a downward facing HSF with the air blowing through the HSF to cool the MB bits in the area. Must try your theory someday and examing circulation patterns... Interesting experiment.

Now the point... Unbalanced CFM's, either intake or exhaust, above about 10% just adds to ineffeciency in fans, lower over all cooling and usually noisier operation environments. My preference would be 5% greater intake than exhaust.

 

[V3NOM]

No argument from me, up to a point. Many of the newer 120 mm fans deliver excellent flows at lower RPS's these days as fan designs are improved. Generally, a 50CFM fan in general will be quieter at a lower operating speed than a 50 CFM at a higher rated speed (made up #'s, BTW). But with some of the newer fan designs... I am amazed at some of the CFM ratings / RPM operating speed. And I agree, hot high speed drives really need their own fan blowing on them. Try cooling cheetahs... Mine sit in an external case, in an un-used closet, with the equivalent of a large-ish house fan blowing on them... As to your HSF test, I really like a downward facing HSF with the air blowing through the HSF to cool the MB bits in the area. Must try your theory someday and examing circulation patterns... Interesting experiment.

Now the point... Unbalanced CFM's, either intake or exhaust, above about 10% just adds to ineffeciency in fans, lower over all cooling and usually noisier operation environments. My preference would be 5% greater intake than exhaust.

LOL? so you think cases are sealed??? mate. i doubt there is a single case on the market that does not have small holes all around it. at the bottom @ the front, sides (some advertise a VGA vent), ALL cases at the back above the expansion slots to the side of the exhaust fan.... everything needs holes. sealed cases are a no go.

 

[croc]

No argument from me, up to a point. Many of the newer 120 mm fans deliver excellent flows at lower RPS's these days as fan designs are improved. Generally, a 50CFM fan in general will be quieter at a lower operating speed than a 50 CFM at a higher rated speed (made up #'s, BTW). But with some of the newer fan designs... I am amazed at some of the CFM ratings / RPM operating speed. And I agree, hot high speed drives really need their own fan blowing on them. Try cooling cheetahs... Mine sit in an external case, in an un-used closet, with the equivalent of a large-ish house fan blowing on them... As to your HSF test, I really like a downward facing HSF with the air blowing through the HSF to cool the MB bits in the area. Must try your theory someday and examing circulation patterns... Interesting experiment.

Now the point... Unbalanced CFM's, either intake or exhaust, above about 10% just adds to ineffeciency in fans, lower over all cooling and usually noisier operation environments. My preference would be 5% greater intake than exhaust.

LOL? so you think cases are sealed??? mate. i doubt there is a single case on the market that does not have small holes all around it. at the bottom @ the front, sides (some advertise a VGA vent), ALL cases at the back above the expansion slots to the side of the exhaust fan.... everything needs holes. sealed cases are a no go.

Does your car engine leak? Do your faucets leak? Do your windows leak? How about your shower surround? Is your case wiring a tangled rat's nest? Cheap cases are not necessarily cheap to buy, they just seem to sell to people that think UV lights and side windows are 'cool'. I think that well sealed cases and adequate sound insulation are important. Go figure.

If I assemble a case and it doesn't meet specs, (mine) I return it. 3M 33 is cheap, so is clear silicon sealer, for those cases that pass minimum specs.

 

[ram1009]

You guys are sure complicating matters. Most of my boxes run with no side panel installed. Never had a heat related problem. Airflow inside a PC is nearly impossible to predict or optimize.

 

[cyber_jockey]

You must realy like the sound of that cpu harddrive and the gpu noise.