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is this enough cooling?

W

Walleye

Limp Gawd
Joined
Jan 13, 2004
Messages
432
my case design

basically, each and every fan will pull from the outside. the psu air will not even enter the main part of the case, it gets flushed out the back. the cpu will draw air through a hole in the acrylic covering it. the 80 mm fan directly over the hard drive will also blow into the case. there will be no exhaust fans, instead it'll just force air out through lots of holes in the rear.

will this be enough cooling? the chip i'll be running is a 1.8 ghz duron, i'm thinking about underclocking it. this board will probably be a via 266 mhz fsb chipset capable of SDRAM, and micro-atx form factor.

will that be enough cooling, or do i seriously need exhaust fans?
 
Are those holes in the back of your case where fans would mount? Essentialy the fans that would be there are "forcing out" air, so I wouldnt think you would absolutly need them.

But I've never read anything or have any good case ventilation experience so take this with a grain of salt. :)
 
so all the fans are on the top, and you plan to have holes all over the back? (just clarifying)

you could try using a 1/8" drillbit and drilling the hex pattern all around the case edge so you're sure to have enough exhaust places to keep it quiet. two things though - only do this if you have a drill press or are really bored, and make sure you brace the metal (i'm assuming it'll be built out of metal)

your handwriting looks a lot like mine! i'm not alone (though i'm not sure that's a good thing;))

other than that it looks good. love the design program you're using there:D
 
In theory all inatkes and no exhaust except forced through much tinier openings will increase air pressure inside of case...Increased air pressure actually will increase heat as the molecules are colliding with one anoher and thus produce heat....

Also that design is not very efficient for air movement and the lack of air flow will cause turbulence and dead zones as the air has no clear path of movement..

I like the cpu idea as I have always.....

However air flow or efficent streamlined movement is the most efficient and when done properly with little resistance actually can be achieved with less rpm fans and thus less noise...

Dont mess with tried and true intake in the lower front leading to exhausting out the back....

I run 2 intakes with one over the HDDS and the other under the HDDs, leading to the back 2.....I actually see case temps 1c higher then room temperature...That is the ultimate mission when it comes to efficient case cooling....I use the side intake fan with ducting to run to the 92mm fan over my swifttech to cut down on recycled air used to cool down heatsink...I find the side case fan alone without this actually cause more turbulence by setting up a cross stream over the front to back stream...



The balance of air removal with air replacement is the key with the least resistance....round cables or cables bundled and secured to the sides as not to block intake air....

I do like the idea of blow holes at the top of the case to allow air that sometimes is inevitably trapped in the top of the case in front of the PSU and behind the top IDE drives....In those area sometimes a sufficent front to rear air flow can pull like a vacumm that heat out but I like it anyways...Use a filter screen so dust and object don't fall in...
 
i would say what Duvie said. also, w/ no exhaust, and higher pressures, it will cause the fans to spin slower if they are not real powerfull, and possibly cause air to come out if your case is nice and tight. i see better temps w/ 1 case fan when it is an exhaust fan.
 
Originally posted by rogue_jedi
so all the fans are on the top, and you plan to have holes all over the back? (just clarifying)

you could try using a 1/8" drillbit and drilling the hex pattern all around the case edge so you're sure to have enough exhaust places to keep it quiet. two things though - only do this if you have a drill press or are really bored, and make sure you brace the metal (i'm assuming it'll be built out of metal)

your handwriting looks a lot like mine! i'm not alone (though i'm not sure that's a good thing;))

other than that it looks good. love the design program you're using there:D
Click to expand...

well..actually it's gonna be made out of acrylic. well... acrylic paneling rabbetted into a skeleton of hardwood. (or maybe poplar.. havent decided yet)

i do in fact have a shopfull of tools (drill press,table saw, radial arm saw, planer, jointer, and router/router table). yeah, i'll have all the fans on top, and all the exit points on the back. so i can cover 4 of 6 sides in padding, as this will be going in a car. (i cant find a way around mounting the hard drive horizontal). also, with this design, i can flip it upside down and mount it under my desk extension top.

http://uploads.thawall.net/pics/comp/dual3.jpg


yeah... crappy writing is where it's at :p lol... and nothing beats a pad of paper, true. lol. :)
 
Originally posted by Duvie
In theory all inatkes and no exhaust except forced through much tinier openings will increase air pressure inside of case...Increased air pressure actually will increase heat as the molecules are colliding with one anoher and thus produce heat....

I like the cpu idea as I have always.....

The balance of air removal with air replacement is the key with the least resistance....round cables or cables bundled and secured to the sides as not to block intake air....

I do like the idea of blow holes at the top of the case to allow air that sometimes is inevitably trapped in the top of the case in front of the PSU and behind the top IDE drives....In those area sometimes a sufficent front to rear air flow can pull like a vacumm that heat out but I like it anyways...Use a filter screen so dust and object don't fall in...
Click to expand...

i suppose i can place a second 80 mm fan just behind the sound card. if it is necessary. this one to pull out air.

the molecules colliding thing isnt really an issue in something like this. seriously, it would have very very little effect, if at all. the air exchanges fully in under a minute, so that wouldnt have any effect..
 
Originally posted by Walleye
i suppose i can place a second 80 mm fan just behind the sound card. if it is necessary. this one to pull out air.

the molecules colliding thing isnt really an issue in something like this. seriously, it would have very very little effect, if at all. the air exchanges fully in under a minute, so that wouldnt have any effect..
Click to expand...

That is why I stated theory...However you will get poor air movement and deadzones where warm air will be trapped and will not be forced out....Flow is key don't try to mess with pressure and expect it to work the way you think....

OVERALL IT IS A POOR CONCEPT....Never should have more intake then exhaust....Balance it or even lean towards more exhaust....

I say at least one intake lower front, 1 exhaust out the back....leave the ducting idea to cpu as I like the idea...

As for blocking the fan on the underside of the power supply??? Another poor idea....The power supply is a lot hotter then the cpu and it needs air movement as well...As long as the fans are properly moving no warm air should be going back into case....If anything maybe some idea to kep sides of the power supply as not to transfer heat into the case that way....

I have tried the power supply idea and all I got was a power supply that ran much hotter from feel of air out the back to the sensor it came with....temps in the 200's+ f...You heatsink will be like what 100-120f to the touch.....Notice how most all the high end makers of power supplies since the 400watt range have this??? It is cause it is needed....YOu are running contrary to their intended design....



Overall play with it and see for yourself....Get some temperature guages and try to chek air throughout the case and along the surfaces....


Sidenote: I turned off my exhaust fan (2 on the back).....Left intakes on....Nowhere near the same amountof air coming out the fan opening as when they are on exhausting....Temperatures in case rising already.....POOR IDEA!!!
 
wait... who ever said i blocked off the PSU's intake fan?

no, the intake fan for the PSU will be flush with the surface of the acrylic, just like the intake fan for the CPU, as well as any other fan. they'll all be flush.

i know you're supposed to run some exhaust.. i assume you have a hardcano or something similar. check temps when you slightly lower the exhaust fan speed. you want to super-pressure the case, because it results in more air pressure, more molecules to spirit away heat.


edit: oh, now i see why you think i blocked off the PSU's intake fan... no, the way this is set up, the case is a total of about 3.5 inches thick. The psu is on it's back, belly up. it's power plug and exhaust go out the same side as the mobo connections, and the fan is in the top, bringing in air from outside the case. that's what i mean by air from the PSU never exchanging with the case air.

(as an aside, the psu i'm using is a sparkle 180 watt power supply. the fans are vantec stealth 80 mm's, and a retail HSF for an athlon XP 2800. (going on a duron 1.8 ghz) the hard drive is a spare western digital 40 gig that i have. the motherboard is a MSI KM2M.. at least that's what i think it's called.)
 
Originally posted by Duvie
In theory all inatkes and no exhaust except forced through much tinier openings will increase air pressure inside of case...Increased air pressure actually will increase heat as the molecules are colliding with one anoher and thus produce heat....
Click to expand...

Theory can be applied anywhere, but the fact is that the ideal gas law is really irellevant in this situation. The tiny increase in pressure is not enough to cause a noticeable change in temperature. And heat is not created by molecules colliding, there is actually no change in heat of the system- just a rise in temperature. To put it simply, temperature increases because there is the same amount of heat now in a smaller volume of gas.
 
huh?

heat is created by friction.. heat is just energy released as heat. friction of molecules DOES produce heat, but to think that that would have any effect here, one would have to only have taken high school chemistry, and only payed attention 1/4 or less of the class.

the volume of air never changes. the pressure of air does change. but the difference is that the more molecules pushed onto the heatsink or exposed areas, the more heat it carries away. and thus, takes out of the case.
 
The fact is your theory I don't see you being able to implement....YOU wil create higher pressure but i don't think the desired air flow patterns will consist to force air out of the case the way you wish....


You have obviously put some thought into it but it just isn't the most efficient way to handle it....What is your ambition of doing this??? What was the intent??

Do some research and go to some of the pure cooling sites and read up...This is not a sound idea no matter how much you think it makes sense in theory...


Also what kind of pressure do you have to build to force the air out at the same pace you would have with exhaust fans??? My case is well sealed with only holes at the fans themsleves and I don't see the air going out the 3 intake slots, and yet with 3 80mm probably doing 2400-3000 rpm range and pushing 30-40 cfm isn't enough to build up this "super pressure".....


Go ahead and do it then reverse the fans and try it, then revrse half the fans and try it and you will see....
 
Originally posted by Walleye
huh?

heat is created by friction.. heat is just energy released as heat. friction of molecules DOES produce heat, but to think that that would have any effect here, one would have to only have taken high school chemistry, and only payed attention 1/4 or less of the class.

the volume of air never changes. the pressure of air does change. but the difference is that the more molecules pushed onto the heatsink or exposed areas, the more heat it carries away. and thus, takes out of the case.
Click to expand...

Friction causes heat, yes, but that's not why pressurized gasses increase in temperature. It's because there is a decrease in volume associated with the increase in pressure. You don't seem to have a good understanding of this, so I suggest you read up on the Ideal Gas Law and Le Chatlier's Principle of equilibrium.
 
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