All fans blowing out of case

Dough1397

Senior member
Nov 3, 2004
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say you blocked all the holes and stuff where air can come up and had 4 of them delta fans all blowing out..... what would be the effects?
 

akira34

Golden Member
Jun 26, 2004
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I'd imagine that the effects would be poor cooling with a TON of noise. Especially with the loud delta fans in use. You're much better off having some fans set to intake and others set to exhaust in the case.
 

S0Y73NTGR33N

Senior member
Sep 27, 2004
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Yeah I like the windtunnel effect in mine... got a nice breeze going actually makes my legs cold... brrr...

-green
 

Navid

Diamond Member
Jul 26, 2004
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You need to allow incoming air to come in. So, you should have an opening in the low front section for air coming in. Whether you have an intake fan or not is a different issue. But, you need to allow air to come in. Otherwise, you reduce the effective air that the exhaust fans move out and you don't allow cool air to come in; not a good setup.
 

Jeff7

Lifer
Jan 4, 2001
41,596
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Plus you'll have dust getting sucked into the case all over the place, rather than into one or two filters.
 

Dough1397

Senior member
Nov 3, 2004
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i dont plan on trying this cause i dont have the equipment or time but w/e

why would cooling be so bad? wouldnt there be a vacuum in the case? and if sealed properly air wouldnt be able to get in? doesnt heat travel better in a vacuum?
 

CheesePoofs

Diamond Member
Dec 5, 2004
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you can't make a vacume with some cheap computer fans.

What you want is air moving over the components, not no air at all.
 

Navid

Diamond Member
Jul 26, 2004
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Originally posted by: Dough1397
doesnt heat travel better in a vacuum?

No it does not!

Heat travels in three ways, conduction, convection, and radiation.

Conduction occurs when heat flows in a body from one part to another or from one body to another if the two are in contact. This happens in solids. The transfer of heat from the CPU to the heat sink or from one part of the heat sink to its fins is by conduction.

Convection occurs in fluids (liquids and gases). The warm air surrounding the heat sink leaves the case by the fans. That is convection.

Radiation is the only way of heat transfer that can occur in vacuum. Like the sun warming you up in a summer day. There is no radiation in a PC.

The air inside a PC needs to be kept cool so that the heat sinks can transfer heat to it. The air is kept cool by convection.

But, as mentioned before, you cannot create a vacuum in a PC case. You can create negative pressure with respect to the outside air. But, the pressure difference is very small since the fans are not that powerful and the case is not perfectly sealed.
 

wisdomtooth

Golden Member
Dec 21, 2004
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Originally posted by: Dough1397
doesnt heat travel better in a vacuum?

A thermos bottle uses vacuum to INSULATE heat so your coffee will stay hot for hours on end.

So if you are an AOLer and you like your hard drive to fry like a mozzarella stick, sure, make an airless case. :p
 

Tiamat

Lifer
Nov 25, 2003
14,068
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Originally posted by: Navid
Originally posted by: Dough1397
doesnt heat travel better in a vacuum?

No it does not!

Heat travels in three ways, conduction, convection, and radiation.

Conduction occurs when heat flows in a body from one part to another or from one body to another if the two are in contact. This happens in solids. The transfer of heat from the CPU to the heat sink or from one part of the heat sink to its fins is by conduction.

Convection occurs in fluids (liquids and gases). The warm air surrounding the heat sink leaves the case by the fans. That is convection.

Radiation is the only way of heat transfer that can occur in vacuum. Like the sun warming you up in a summer day. There is no radiation in a PC.

The air inside a PC needs to be kept cool so that the heat sinks can transfer heat to it. The air is kept cool by convection.

But, as mentioned before, you cannot create a vacuum in a PC case. You can create negative pressure with respect to the outside air. But, the pressure difference is very small since the fans are not that powerful and the case is not perfectly sealed.

Actually, there is thermal radiation within your case. It is just very small.
 

Navid

Diamond Member
Jul 26, 2004
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Originally posted by: Tiamat

Actually, there is thermal radiation within your case. It is just very small.

Yes, it is negligible. That is why I neglected it!

But, to be accurate, I should have said that all three kinds of heat transfer occurred inside a case. Conduction is the main form inside the heat sink. Convection is the main form in the air. Thanks for correcting me.

But, the point remains; the only way for the heat to get out of the case is through air. Vacuum will not do!
 

MrControversial

Senior member
Jan 25, 2005
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Can you say vacuum? Keep in mind that some components in the computer are relying on cold, fresh air coming in like the HSF. When the fan blows the heatsink, it's expecting to blow cooler air over the sink.
 

akira34

Golden Member
Jun 26, 2004
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Originally posted by: wisdomtooth
Originally posted by: Dough1397
doesnt heat travel better in a vacuum?

A thermos bottle uses vacuum to INSULATE heat so your coffee will stay hot for hours on end.

So if you are an AOLer and you like your hard drive to fry like a mozzarella stick, sure, make an airless case. :p

The thermos bottle with a vacuum inside of it has the vacuum between two layers of material to BLOCK heat transfer. There are other thermos that use glass or other insulation materials/methods to keep things inside either hot or cold.

Something else (not really on topic, but I'm posting it anyway)... There is tank armor that uses a vacuum between layers of material in order to block incoming rounds from penetrating all the way through. With the layers of material and vacuum they get away with lighter armor plating that's very effective. At least lighter and more effective than the same thickness of solid plating.
 

shira

Diamond Member
Jan 12, 2005
9,500
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Originally posted by: Dough1397
say you blocked all the holes and stuff where air can come up and had 4 of them delta fans all blowing out..... what would be the effects?

The vacuum you create with this setup would cause the case to collapse in on itself, until it became a black hole and destroyed the entire universe. The end.

 

akira34

Golden Member
Jun 26, 2004
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Originally posted by: shira
Originally posted by: Dough1397
say you blocked all the holes and stuff where air can come up and had 4 of them delta fans all blowing out..... what would be the effects?

The vacuum you create with this setup would cause the case to collapse in on itself, until it became a black hole and destroyed the entire universe. The end.

Riiiiiiiiiiiight...
 

Gamingphreek

Lifer
Mar 31, 2003
11,679
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ALso remember you CPU fan blows on your CPU. If you have all air going out it does indeed create a miny vacuum (ie not much air obviously there is still air there though) and it starves the CPU for air.

-Kevin
 

BW86

Lifer
Jul 20, 2004
13,114
30
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I had an intake and an exhaust on my case a week ago. My intake fan started making noise so I took it out. I was curious to see what temps I was going to get with the intake fan off and was suprised to see that my case and cpu temp went down a degree or two. 32 to 30 for the case and 38 to 37 for the cpu.
 

MrControversial

Senior member
Jan 25, 2005
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Just to add, you want moving in your case as well. Cool air should be flowing across the motherboard. That's the purpose of intakes and exhausts.