Acheiving the best airflow through case?

[FrozenLiquidity]

Does anyone know of a site that has specific information about how to improve airflow thorugh a case?

I need to know what I have to get to acheive the best cooling for my computer in progress.

Thanks

FrozenLiquidity

[tonym]

Frozen...

The best way to improve airflow in a case is to evacuate the hot air out of the TOP of the case. Hot air rises...and obviously the best hing to do is to vent it from the case top.

Why don't case vendors do this? They:

a.) don't understand thermodynamics,
b.) they want to make cheap cases by the gazillions,
c.) until the appearance of the PII and Athlon, not a heck of a lot of heat was generated (usually less than 150W loadside), and
d.) just like all the legacy stuff around, it will take a vendor with cohones to advocate and proliferate change!

Have you ever wondered why the heatsinks on a PCI card face down?? Dumbass legacy, that's why!

So, you can improve the airflow in your case by adding two fans to the top, blowing up (out). Yes, you have to cut holes and add fan guards, but the performance increase in cooling is well worth it!

Also, a little air turbulence in the PCI card areas helps as well...bend up a metal bracket that can hold a small fan pointed at the PCI cards (particularly the video card) and you'll move the stale air about in that area...to be carried away by the new topside evacuation fans!


Try it out, you'll be very pleased!


Tony

[FrozenLiquidity]

I already have a fan at the top of my case blowing air out. I can see the CPU and heatsink through the fan, so I think it will keep the processor pretty cool.

But I am looking for tips and suggestions to get the maximum amount of airflow and the lowest tempatures in the case.

FrozenLiquidity

[zzzreyes]

As my fellow engineer has so eagerly tryied to explained to you, by adding ventilation to your case you will get rid of any exess heat.
But know if u want to get really fancy, we can run some copper lines from the inside of your case to the outside of the case from the motherboard side....

But I still think that the way he xplained would b the most efficient when taken money and time as a variable into the equation

[FrozenLiquidity]

I know all of that already!
I'm looking for advanced techniques and specific fan placement for maximum cooling.

Thanks

FrozenLiquidity

[NavyDood_ F/A18_Mech]

I have two 3" fans sucking air straight up from the bottom of the case with filters. Then I have two 3" fans sucking the air out at the top rear. I cut my IDE cables into strips to make them a round shape and used zip ties to hold it. I routed all my wires and such so that they hug any flat surface that they can. This way they aren't just hanging in the way and disrupting the airflow.

Hope this helps.

[tonym]

Frozen,

I've been a project manager for hardare for several large, power hungry computer systems larger than walk-in refrigerators. Lots of power 3000~6000W system draws. As it is remarkably difficult to cool the individual subsystems in the MOST effective manner, you make trade-offs.

But you use several assumptions/precepts guided by the physics of the system:

a.) hot air rises,
b.) maximize air velocity where ever possible,
c.) utilize turbulence to "scrub" stagnant air from obstructed areas,
d.) if the thermal impedance of the system is too small, push air from the bottom as well as pull air from the top,
e.) use heatsinks that have cast a minimum thermal shadow on surrounding components,
f.) if you experience ambient temperature swings, use two speed fans to "sprint" at high speed while the ambient temp is high.

Remember that heat is transferred by three means: convection, conduction and radiation. heatsinks conduct the heat from the power dissipating element(s) and allow convection by still or moving air as a result of the large surface area they present to the ambient air (convoluted fins). Radiation plays no real part in a closed computer system -- it does from the sun, however!

I understand that you want the best cooling cooling. This means that you must sweat the details to remove the heat effectively:

1.) identify all the heat sources,
2.) measure or calculate their power dissipation,
3.) obtain the thermal resistance for each power dissipating element (juntion to case, case to heatsink and heatsink to ambient),
4.) deploy your cooling scheme and measure air velocities at each of the power dissipating elements,
5.) calculate the temperature rise for each element and determine if it's too high based on your initial requirements (temp rise or reliability goal or ??),
6.) if it's OKAY, quit and enjoy your computer!,
7.) if it's too high, iterate and make the heatsink larger and or increase the airflow or use a more exotic cooling scheme (Peltier, heat pipe.

And remember, don't use thermal grease like peanut butter! A little film works the best.

For a situation like a PC, the best possible means to obtain the BEST cooling is experimentation -- trial-and-error. Get youself a lab notebook and make the exercise an experiment! Keep accurate notes and you'll eventually get to the BEST cooling scheme for you situation.

There is no cut-and-dried cookbook to list actions and the outcomes for cooling a PC. Advice that you'll get here (listen to Navy_Dood!!) and elsewhere will help you to learn and make the BEST decisions for the BEST cooling for your system!!!

Good luck and give updates...


Tony

[krusty the klown]

Something like this should do the trick:
http://www.overclockers.co.uk/acatalog/coolercase_tornado.jpg

(praps overkill, but looks like it does the job!)

As Tony says, there will be some trial and error involved. I guess you've achieved the optimum case ventilation when you do not notice much difference in component temperatures between having the case on or off.

[jadison]

Krusty: I agree, that Tornado case is supreme!! I'd get it if I had the $$$, esp. the others on that site.

Frozen: Check this out: http://sysopt.earthweb.com/forum/Forum3/HTML/005296.html

I know it's an old thread, but there's some ideas of mine I had about the same thing your asking about. Post some pics of your setup, if you can! Happy Cooling!

-=jd=-

[x35Agent]

Good Job Tonym!!! A Great help to us all i'm sure. I hope this helps out the Great Frozen One. http://sysopt.earthweb.com/forum/smile.gif

[Ultima]

Well,

I'm busy with a project that will give me max aircooling in my case, I hope!!!

I have build a block of 12 systemfans, which is designed to cover the whole mobo at once!!!

6 fans in the front of the case will suck air out, and the 4 fans in the back too!!!

I also have 2 9cm fans that are positioned at the top of the case, for the hot air!!!!

That makes a total of 24 system fans, and that is only the case,hehehe.

I'll soon make some pictures and will measure the temp of the mobo and cpu!!!
It should drop a few degrees, no??!!

Pim

[tonym]

Ultima,

REMEMBER, if you suck too much air out of the case and you don't replentish it fast enough, you get a vacuum! And **** poor cooling along with it!!!

The thing you want to do is determine what airflow you want (i.e how many case air volume "turns" per unit time). This would be the volume of the case in cubic feet and the time unit is minutes (CFM!). You then want to move this amount of air with the available fans (X fans times Y CFM for intake and exhaust). Anything greater than this, your're wasting power on the excess fans. Anything less, and you're getting hotter than you want.

Also, if you have 5 fans blowing in and 3 fans blowing out, you're pressurizing the case and getting poor cooling as a result. If you have 5 fans exhausting and 3 fans intaking (and no other vent holes), then you're creating a vacuum, and you also get poor cooling. If you're doing the push-pull cooling thing, make sure it's volume balanced!

And also, if you're using multiple fans to exhaust cool your case (only), make sure you have adequate ventilation holes along the bottom of the case such that you don't inadvertnely create a vacuum with your mega-CFM exhaust fans!!!

Just something to think about...


Tony