Positive vs negative pressure - Overclock.net - An Overclocking Community

Forum Jump: 

Positive vs negative pressure

Reply
 
Thread Tools
post #1 of 20 (permalink) Old 11-09-2019, 09:28 AM - Thread Starter
New to Overclock.net
 
Join Date: Oct 2019
Posts: 9
Rep: 0
Positive vs negative pressure

Hi everyone. Im new to the forums and this might be a dumb question but im planning on making my own pc case.
It will be wall mounted closed case.
The main concern atm, before i start cutting are the fan placements.

The idea i had was to use 4x12mm pressure optimised fans as intake, all lined up at the front (it will be wall mounted, keep in mind what is the "front"). PO fans becouse biggest concern i read on most of the forums is dust buildup so i plan on using filters which as I've also read limits airflow with regular fans.
With this option i will leave top passive exaust considering the pissitive pressure.


The other option is 4x12cm exhaust on top with passive filtered intake.

No components will be water-cooled so im asking on opinions and advices. The case will be airtight so no dust will get in through any cracks if i decide on negative pressure with passive filtered intake.

Sent from my Mi A1 using Tapatalk
cezzey is offline  
Sponsored Links
Advertisement
 
post #2 of 20 (permalink) Old 11-11-2019, 05:53 PM - Thread Starter
New to Overclock.net
 
Join Date: Oct 2019
Posts: 9
Rep: 0
Any1?

Sent from my Mi A1 using Tapatalk
cezzey is offline  
post #3 of 20 (permalink) Old 11-11-2019, 05:59 PM
9 Cans of Ravioli
 
The Pook's Avatar
 
Join Date: May 2006
Posts: 17,128
Rep: 1154 (Unique: 660)
have more CFM going in than out and use filters if you want to get rid of dust. if you don't want dust then you need dust filters and dust filters limit airflow, you can't have your cake and eat it too.

If you have positive case pressure you don't need any exhaust fans. Your case isn't air tight and it's not going to turn itself into a pressure cooker, it's just going to naturally exhaust out where it can.

Intel i9 9900K Coffee Lake @ X8 5309mhz (+47.5%)
AMD FX-8320 Vishera @ X4 5022mhz (+43.5%)
Intel i5 4690K Haswell @ X4 5013mhz (+43.2%)
AMD X4 960T Zosma @ X6 4870mhz (+62.3%)
Intel i7 6700 Skylake @ X4 4709mhz (+38.5%)
Intel i5 6400 Skylake @ X4 4588mhz (+69.9%)
2 OP pls nerf
(24 items)
NUC U
(10 items)
CPU
i9 9900K
Motherboard
AsRock Z390 Taichi
GPU
MSI GTX 1080 Ti
RAM
G.Skill DDR4 4133 32GB
Hard Drive
Mushkin Pilot NVMe 1TB
Hard Drive
HP EX950 NVMe 2TB
Hard Drive
Samsung 860 Evo 1TB
Hard Drive
Sandisk Ultra II 480GB SSD
Hard Drive
Toshiba X300 5TB
Hard Drive
Western Digital EZRZ 3TB
Power Supply
Seasonic Focus Plus Gold 750w
Cooling
Corsair H115i Pro
Case
Fractal Design Meshify S2
Operating System
Windows 10 Education x64
Monitor
Acer XF270HU 27" 1440p
Monitor
LG 24UD58 24" 4K
Keyboard
CoolerMaster MasterKeys Pro S
Mouse
Logitech G502
Audio
SMSL SA50 + FiiO E10K
Audio
Micca RB42
Audio
Polk Audio PSW111
Audio
Philips Fidelio X2
Audio
Philips SHP9500S
Audio
Audio Technica ATH-M50X
CPU
i3 8109U
Motherboard
Intel NUC8i3BEH
GPU
Iris Plus 655
RAM
Kingston 8GB DDR4 2400
Hard Drive
Dierka K1 120GB
Hard Drive
ADATA SU800 128GB M.2
Operating System
Windows 10 Professional
Operating System
MX Linux
Keyboard
Dierya DK63-BT 60% (Outemu Blue)
Mouse
Logitech M510
CPU
i7 860
Motherboard
Advantech AIMB 280 ITX
GPU
EVGA GTX 950 2GB
RAM
Kingston 2GB DDR3 1333
Hard Drive
Seagate Momentus 2.5" 500GB
Hard Drive
Western Digital Blue 2.5" 320GB
Power Supply
Silverstone SFX-L Gold 500w
Cooling
Arctic Alpine 11 GT 2
Case
Silverstone Milo Z ML07B
Operating System
Windows XP x86 SP3
Keyboard
Velocifire TKL01 Outemu Browns
Mouse
Logitech M512
▲ hide details ▲


The Pook is offline  
Sponsored Links
Advertisement
 
post #4 of 20 (permalink) Old 11-12-2019, 10:26 AM
New to Overclock.net
 
StAndrew's Avatar
 
Join Date: Sep 2008
Posts: 197
Rep: 13 (Unique: 9)
Is your GPU air cooled? Negative case pressure will limit how much heat is exhausted through the GPU exhaust vent and positive pressure will help expel GPU heat out the vent. Is your PS drawing air from inside the case? Same.

Generally positive pressure is preferred, however, if the GPU and PS were not a factor, neutral pressure will give the most efficient flow of air through the case.

When calculating air flow, its just just the number of fans you have as intake vs exhaust, you also have to take into account flow restrictions such as grills, dust filters, etc...

Asus Prime Z370, Intel 8700k @5.0Ghz, Nvidia GTX 1080 Ti, 16GB @3400 CL14, Watercooling: x2 MCP355 pumps, x1 280 on front of case, x1 360 on top of case, x1 140 on back of case, x1 240 on bottom of case

Last edited by StAndrew; 11-12-2019 at 10:36 AM.
StAndrew is offline  
post #5 of 20 (permalink) Old 11-12-2019, 10:42 AM
Tech Enthusiast
 
deafboy's Avatar
 
Join Date: Jan 2008
Location: San Diego
Posts: 12,172
Rep: 441 (Unique: 336)
What kind of case? I've never seen a closed off wall mounted system

IN HONOR OF SYRILLIAN, R.I.P.
ASUS ROG Rampage IV Black Owners Club || PNW Overclockers Club
BMW TJ07 Build Log -- The Ultimate Cooling Machine
2 year anniversary In Remembrance of a Great - RIP Syrillian
Overkill FreeNAS
(10 items)
CPU
Intel Xeon E5-1680 V2
Motherboard
Asus Rampage IV Black Edition
GPU
nVidia Titan XP (2100/5200)
RAM
Corsair Dominator Platinum 32GB
Hard Drive
Intel 750 400GB
Hard Drive
Intel 750 1.2TB
Hard Drive
Samsung PM981 1TB
Power Supply
Corsair AX1200i
Cooling
2x Swiftech D5 w/ EK Dual Pump Top
Cooling
XSPC EX480, EX360 & 2x Phobya 1080
Cooling
EK Supremacy EVO CPU Block
Cooling
EK Advanced 250mL Res
Cooling
Lamptron FC-5V2
Cooling
EK Rampage IV BE Water Block
Cooling
Copper Tubing w/ push fittings
Cooling
EK-FC Titan XP Copper/Acetal
Case
Silverstone TJ07, heavily modified
Operating System
Windows 10 Pro
Monitor
Asus PG297Q
Keyboard
Leopold Otaku
Mouse
Corsair M65
Mouse
Corsair MM600
Audio
Sennheiser HD595 / HD428 / HD280
Audio
Corsair SP2500
CPU
E5-2670v1
CPU
E5-2670v1
Motherboard
Supermicro X9DRL-iF
Hard Drive
12x HGST 4TB CoolSpin
Hard Drive
6x WD Red 8TB
Power Supply
Corsair AX750
Cooling
2x Noctua nh-u9dxi4
Cooling
3x Scythe AP-30
Case
Norco 4224
Operating System
FreeNAS
▲ hide details ▲


deafboy is offline  
post #6 of 20 (permalink) Old 11-12-2019, 11:58 AM - Thread Starter
New to Overclock.net
 
Join Date: Oct 2019
Posts: 9
Rep: 0
I'm building a custom case from the scratch. This was the plan for first look and dimensions, and first idea for fan placement (will look cool also as i will put the filters on the inside, fans will be fully visible, but still make the fans easy to remove for cleaning purposes. The picture is showing the front panel (imagine it hanging on the wall).

Gpu will be inside. Eventually i am planning to use standoffs, above the motherboard, and a gpu riser and position the gpu so that the intake fans blow like 30% directly on the gpu which then will be face monted, and the rest 70 %will go bottom towards the cpu and the mobo.
Another option is to place it above the 120mm fans and make another smaller cuts (100mm) just for the gpu so it can get its own fresh air from the outside but i worry about dust. Filtering it will limit the intake, and leaving it open will suck the dust straight in...would look great tho

Psu will be in the bottom corner, pulling air from the side and expell it immediately on the bottom (it doesnt get heated so im not concerned about the heat rising up from it, so it wont interfere with the case airflow.


The case is work in progress, just started it and taking my time, but it will be airtight (if that's the right word for it), in terms that if i decide on negative pressure there wont be any dust entering through any cracks beside those i leave opened and filtered ))

In the case of 4x120mm intake, the top will be cut (not whole top but some sort of pattern) as a passive exhaust.

-4x120mm top exhaust will have filtered front passive intake.

That's the general ideas i had for the fan placements as i want to keep it simply top to bottom but my lack of experience in the matter cant decide which is better or is any of it any good ))



Sent from my Mi A1 using Tapatalk
cezzey is offline  
post #7 of 20 (permalink) Old 11-12-2019, 11:59 AM
New to Overclock.net
 
StAndrew's Avatar
 
Join Date: Sep 2008
Posts: 197
Rep: 13 (Unique: 9)
Quote: Originally Posted by deafboy View Post
What kind of case? I've never seen a closed off wall mounted system
He's making his own case.

Asus Prime Z370, Intel 8700k @5.0Ghz, Nvidia GTX 1080 Ti, 16GB @3400 CL14, Watercooling: x2 MCP355 pumps, x1 280 on front of case, x1 360 on top of case, x1 140 on back of case, x1 240 on bottom of case
StAndrew is offline  
post #8 of 20 (permalink) Old 11-12-2019, 12:05 PM
New to Overclock.net
 
StAndrew's Avatar
 
Join Date: Sep 2008
Posts: 197
Rep: 13 (Unique: 9)
Quote: Originally Posted by deafboy View Post
What kind of case? I've never seen a closed off wall mounted system
Re-Repost

Asus Prime Z370, Intel 8700k @5.0Ghz, Nvidia GTX 1080 Ti, 16GB @3400 CL14, Watercooling: x2 MCP355 pumps, x1 280 on front of case, x1 360 on top of case, x1 140 on back of case, x1 240 on bottom of case

Last edited by StAndrew; 11-12-2019 at 12:12 PM.
StAndrew is offline  
post #9 of 20 (permalink) Old 11-12-2019, 12:10 PM
New to Overclock.net
 
StAndrew's Avatar
 
Join Date: Sep 2008
Posts: 197
Rep: 13 (Unique: 9)
Repost

Asus Prime Z370, Intel 8700k @5.0Ghz, Nvidia GTX 1080 Ti, 16GB @3400 CL14, Watercooling: x2 MCP355 pumps, x1 280 on front of case, x1 360 on top of case, x1 140 on back of case, x1 240 on bottom of case
StAndrew is offline  
post #10 of 20 (permalink) Old 11-20-2019, 08:13 PM
New to Overclock.net
 
TeslaHUN's Avatar
 
Join Date: Feb 2016
Posts: 367
Rep: 20 (Unique: 18)
If your case will be sealed totally ,then full negative pressure would work just as fine as positive .
Im working on a project ; building my own PC case from wood , and i will be using 15-17 fan all of them exhaust . But making a cutting out a passive intake area with good dust filter ( furnace filter / HEPA ). As long as all gap(except the exhaust an ofc) has dust filter i prefer negative ,over positive .
TeslaHUN is online now  
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Overclock.net - An Overclocking Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off