Air Flow Direction for dual rad. setup...

jtroutma · 06-19-2002, 04:30 PM

Here is an interesting question:
I am planning on installing a Black Ice II or similar radiator into the bottom of my case. My question is; should I have the fans pulling air from under my case into the computer OR should I have the fans pushing air from inside the case out the bottom of the case.

I have made a picture to try and illustrate what I have in mind.

I know that the coolest air in my place is at the bottom of the case and thus think that pulling air from underneath my case up to the top and blowing it out from the top-back would probably work the best. However, pushing air though a Radiator always seems like the best way of cooling it and the air will have a small place to travel to thus more static pressure.

What do you guys think?

chazz469 · 06-19-2002, 04:48 PM

I have heard that pulling air thru the rad is better. And I've thought about putting a hole in the floor of my case too, but just for ventilation. Anyhow, I think that if you put the fan on top of the rad, blowing into the case, with an exhaust at the top you would get cooler. Be sure to put a fan filter on the hole though. Intake from the floor would be cool, but dirty.

redleader · 06-20-2002, 01:16 AM

First I'd ditch the cube. 1/2 or not, thats got to be hurting flowrate. Besides, I think a BI2 can more then handle itself.

Brad · 06-20-2002, 02:05 AM

have the fans on the BI2 blowing in

gmat · 06-20-2002, 05:22 AM

Yep axial fans work best when "pulling". And looking at your setup it makes even more sense since hot air rises...

bigben2k · 06-20-2002, 08:20 AM

I agree with Brad. Have them flow in. Reason: you need the airflow inside to cool the rest of the mobo and peripheral cards. The BI2 is your hot rad though, but that's OK, because you have lots of airflow. Since you'll have positive pressure in the case, you should allow some air to get out, preferably at the top and back.

Also, if you like, you can use a filter under your BI2, to prevent dust from accumulating, and reducing your rad's efficiency. I'd go with something light and fluffy, just be creative.

(NIce to see gmat back!) Yes, the fans are better at pulling, but only because pushing requires sealing, to prevent the fan from recirculating air around itself. Actually, the problem exists either way...

gmat · 06-20-2002, 10:08 AM

Yep, what BB2K said...

Add to this:
* You'd want slightly 'negative' pressure. Positive pressure is bad. There are both theoric and experimental (=proven) reasons, but since i'm at work i dont have the links right here. To this end you'd want to get rid of the front 80mm - or have it blowing out at reduced voltage (depends on whats in the PSU - not shown on your schema). results = less noise, less heat, less dust and better airflow.
* Fans are way better at 'pulling' because of the aforementioned reason (negative pressure) which induces a 'draft' which goes the 'good way' through the fan. There are more complex reasons (blade tip vortex etc...) but it's the main one.
* Make sure you seal any other hole in your case, specially on its underside.
* Post photos for our viewing pleasure

[edit] seeing your schema again, reverse your aquacoil setup - have the 120mm blow out of your case.

jtroutma · 06-20-2002, 12:09 PM

Thanks for the replys guys.

As for the front 80mm fan, that is there ONLY as a cooling option for my pump (so that it doesnt get too hot; and it can if it doesnt have a bit of airflow right on it) Besides that fan only puts in say 20CFM.

Powersupply is an Enermax with a 92mm underside fan and an 80mm exhaust. It dumps a decient amount of air out of the back but not exceptional.

AS for the positive pressure in the case, I doubt it due to the fact that where my RAID array is, I have no covers in the font so somehow IF I get too much airflow into the case the excess will flow out the front. NOT the best but will work.

Also just decided on useing some adjustable Enermax 120mm fans for use on the BI2 rad. because they are quite, good price, and even adjustable (for when I need a little bit more cooling

)

AS for the AquaCoil, I might as well just leave it in there. It is hard modded into the case, serves as a peliminary/extra Rad, keeps the air circulating in the case, and flow rate seems to be fine. Granted my flow rate could be improved, but then again I can always just bump up the pump a bit too

Other mods that I am planing on:
TC-4 CLear top WaterBlock
56W pelt + copper plate on GF3 (to make room for the BL2)

BTW On the BL2...not sure If I should use Brads idea about adding a 1/2" fitting to the middle of the rad and use the 3/8" for outtakes (turn it into a 2 pass rad. X 2) OR simply mod both 3/8" to 1/2" ( 4 pass Rad. X 1). Suggestions welcome!!!!

06-19-2002, 04:48 PM	#2
chazz469 Cooling Savant Join Date: Jun 2002 Location: San Diego, CA Posts: 150	I have heard that pulling air thru the rad is better. And I've thought about putting a hole in the floor of my case too, but just for ventilation. Anyhow, I think that if you put the fan on top of the rad, blowing into the case, with an exhaust at the top you would get cooler. Be sure to put a fan filter on the hole though. Intake from the floor would be cool, but dirty. __________________ "I believe that the moment is near when by a procedure of active paranoiac thought, it will be possible to systematize confusion to the total discrediting of the world of reality" -Salvador Dali AMD XP1600+ @1790MHz and rethinking my cooling.... MAZE3 --> DD Cooler Cube --> Eheim 1048 512MB PC2700 DDR MSI KT3 Ultra-ARU 2x 20GB Maxtor in RAID 0 1x 30GB Maxtor --> WinXP GF3 Ti200 @ 240/499

06-20-2002, 02:05 AM	#4
Brad Thermophile Join Date: Oct 2001 Location: Nuu Zeeelin Posts: 3,175	have the fans on the BI2 blowing in __________________ 2x P3 1100's at 1400, Abit VP6, 2x Corsair 256mb PC150 sticks, 20gb 'cuda ATA-III, 2x 40gb 'cuda ATA-IV in raid 0. 20" Trinitron. No fans 2x 2400+ at 2288mhz (16.0 x 143), Iwill MPX2, 2x Kingmax PC-3200 256mb sticks, 4x 20gb 60gxp in Raid 5 on a Promise SX6000. Asus Ti4200 320/630. Cooled by Water

06-20-2002, 08:20 AM	#6
bigben2k Responsible for 2% of all the posts here. Join Date: May 2002 Location: Texas, U.S.A. Posts: 8,302	I agree with Brad. Have them flow in. Reason: you need the airflow inside to cool the rest of the mobo and peripheral cards. The BI2 is your hot rad though, but that's OK, because you have lots of airflow. Since you'll have positive pressure in the case, you should allow some air to get out, preferably at the top and back. Also, if you like, you can use a filter under your BI2, to prevent dust from accumulating, and reducing your rad's efficiency. I'd go with something light and fluffy, just be creative. (NIce to see gmat back!) Yes, the fans are better at pulling, but only because pushing requires sealing, to prevent the fan from recirculating air around itself. Actually, the problem exists either way... __________________ WBTA (Water Block Testing Alliance) Nordic Hardware WC 101

06-20-2002, 10:08 AM	#7
gmat Thermophile Join Date: Mar 2001 Location: France Posts: 1,221	Yep, what BB2K said... Add to this: * You'd want slightly 'negative' pressure. Positive pressure is bad. There are both theoric and experimental (=proven) reasons, but since i'm at work i dont have the links right here. To this end you'd want to get rid of the front 80mm - or have it blowing out at reduced voltage (depends on whats in the PSU - not shown on your schema). results = less noise, less heat, less dust and better airflow. * Fans are way better at 'pulling' because of the aforementioned reason (negative pressure) which induces a 'draft' which goes the 'good way' through the fan. There are more complex reasons (blade tip vortex etc...) but it's the main one. * Make sure you seal any other hole in your case, specially on its underside. * Post photos for our viewing pleasure [edit] seeing your schema again, reverse your aquacoil setup - have the 120mm blow out of your case. Last edited by gmat; 06-20-2002 at 10:10 AM.

06-20-2002, 12:09 PM	#8
jtroutma Cooling Savant Join Date: Aug 2001 Location: SLO, CA Posts: 837	Thanks for the replys guys. As for the front 80mm fan, that is there ONLY as a cooling option for my pump (so that it doesnt get too hot; and it can if it doesnt have a bit of airflow right on it) Besides that fan only puts in say 20CFM. Powersupply is an Enermax with a 92mm underside fan and an 80mm exhaust. It dumps a decient amount of air out of the back but not exceptional. AS for the positive pressure in the case, I doubt it due to the fact that where my RAID array is, I have no covers in the font so somehow IF I get too much airflow into the case the excess will flow out the front. NOT the best but will work. Also just decided on useing some adjustable Enermax 120mm fans for use on the BI2 rad. because they are quite, good price, and even adjustable (for when I need a little bit more cooling ) AS for the AquaCoil, I might as well just leave it in there. It is hard modded into the case, serves as a peliminary/extra Rad, keeps the air circulating in the case, and flow rate seems to be fine. Granted my flow rate could be improved, but then again I can always just bump up the pump a bit too Other mods that I am planing on: TC-4 CLear top WaterBlock 56W pelt + copper plate on GF3 (to make room for the BL2) BTW On the BL2...not sure If I should use Brads idea about adding a 1/2" fitting to the middle of the rad and use the 3/8" for outtakes (turn it into a 2 pass rad. X 2) OR simply mod both 3/8" to 1/2" ( 4 pass Rad. X 1). Suggestions welcome!!!! __________________ Athlon64 X2 4200+ @ 2.5Ghz (250FSB x 10) OCZ VX 1GB 4000 @ 250FSB (6-2-2-2 timmings) DFI LANParty nForce4 Ultra-D SCSI Raid 5 x (3) Cheetah 15K HDDs LSI Express 500 (128MB cache) OCZ PowerStream 520W PSU ATI X850XT PE (Stock) DTEK WhiteWater + DTEK Custom Radiator Eheim 1250

06-20-2002, 01:16 AM	#3
redleader Thermophile Join Date: Jun 2001 Location: The deserts of Tucson, Az Posts: 1,264	First I'd ditch the cube. 1/2 or not, thats got to be hurting flowrate. Besides, I think a BI2 can more then handle itself.

06-20-2002, 05:22 AM	#5
gmat Thermophile Join Date: Mar 2001 Location: France Posts: 1,221	Yep axial fans work best when "pulling". And looking at your setup it makes even more sense since hot air rises...

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