All about air: Pressure, Flow, CFM, ECT

[spwath]

OK so this is a post to clear thing up about air and how it works. First of all let me say something alot of people dont know. POSITIVE AIR PRESSURE DOES NOT PREVENT OR LESSEN DUST, UNLESS YOU HAVE FILTERS. Some people dont know this. They have a case with no filters, put positive air pressure in, and say it helps with dust. It does not.
 

Vocab

Positive Air Pressure: Formed when more air goes in than out. Dont judge by amount of fans or size, judge by total CFM of the fans, for example, if you have 3 120mm fans intakeing with 30 CFM each, and 3 fans exauseitng with 20 CFM each, you would have positive air pressure.

Negative Air Pressure: Same as positive, but more air goes out than in.

Air Flow: How air moves through a case. LIke front bottom to top back, as found most commonly.

CFM (Cubic Feet Per Minute): The amount of air a fan moves

M3/H (Cubic Meter Per Hour): Like CFM, 1 CFM=1.7 M3/H

Decibels (db): Noise of a fan. Anything below 30 is quiet but many times the listed specs are not correct.

Static Pressure: The amount of pressure a fan has, higher is better for radiators, heatsinks, and restrictive panels.

MM H2O: Units to measure static pressure

Fan Control:

PWM: Pulse Width Modulation. This is a 4 pin connector that would usually be on your motherboard. Can easily fine tune RPM via software. Usually more expensive, but greater software control

Voltage Control: This is on your standard 3 pin fan. There are simple adapters to slow it down from the standard 12V to 9V, 7V, and 5V. Most hardware fan controllers can fine tune it more, using regular 3 pin fans.

Case Airflow:

Ideal airflow is straight, Front to Back, Or Bottom to Top. Most cases do not have this, some do. Some cases that have this are H440, S340, and Silverstone Fortress and Raven Cases. However, it seems to be becoming a new trend with cases like the define s.
This means in cases that have sufficient front intake, a top fan can actually increase temps.

Examples of Phantom 410, R4, H440, 750D, Prodigy, S340, and Enthoo Luxe/Pro, all different types of heatsinks and AIO's. Ask for another case and Ill add it!

Phantom 410 Airflow: Large heatsink, blows toward back.

I would recommend removing top front fan i highlighted in green. If you dont want to remove it, reconfigure it as an intake there if all you other intake spots are filled. For Optimal cooling with this setup/ i would recommend 1x back exhaust 1x top back exhaust, 2x front intake, 1x bottom intake, and an optional top front intake and side intake.

Phantom 410 Airflow: Large heatsink, blows up.

I would recomend first populating the side intake, then front top, then bottom, then top 2, then front bottom, then back.

Phantom 410 Airflow: Motherboard blowing heatsink

I would not recomend this kind of heatsink for a large case, only for ITX rigs.

Bitfenix Prodigy Airflow: Tower heatsink

I would recommend having either 1 200/230mm fan in front or 2 120 in front (1 230 will yield better noise to airflow, 2 120 will make more air, and can be as quiet/quieter with good fans) and 1 fan exhausting out the back. Optional fans would be one top front intake (Note, get a dust filter for this), and one top back exhaust. Intakes shown as blue, exhaust red, optional green.

Bitfenix Prodigy Airflow: 120mm AIO liquid cooling

I would recommend the same 200/2x 120mm in front as before, the radiator mounted in back, and the top fans as optional intakes (Note, get dust filters for these). Intake blue, exhaust red, optional green.

Bitfenix Prodigy Airflow: 240mm AIO liquid cooling

I would recommend same 200/2x 120mm in front as before, radiator on top as exhaust, and rear fan as an intake (Note, get a dust filter for this). Intake blue, exhaust red.

Define R4 Airflow: Tower heatsink- Blowing back

I would recomend 2 front intakes, 1 rear exhaust, optional top front intake (get a dust filter for this), option top rear exhaust, optional bottom intake. Blue intake, red exhaust, green optional.

Define R4 Airflow: Dual Tower heatsink- Blowing back

I would recommend 2 front intake, 1 rear exhaust, and optional bottom intake. I would not recommend anything on top. Blue intake, red exhaust, green optional.

Define R4 Airflow: Stock cooler

I would recomend 2 front intake, 1x rear exaust, optional bottom intake, and optional top back exhaust. Blue intake, Red Exhaust, Green optional.

Define R4 Airflow: 120mm AIO Liquid Cool

I would recommend 2 front intake, radiator on top back or back as exhaust, the other position of the two mentioned configured as an intake (Get a dust filter for this). Optional bottom intake. Blue intake, red exhaust, green optional.

Define R4 Airflow: 240mm AIO Liquid cool

I would recomend 2 front intake, radiator on top as exhaust, rear intake (get a dust filter for this) and optional bottom intake.

750D Airflow: Tower Cooler

I would recomend for a single tower cooler to have 2x intake fan in front, 1x intake fan in bottom back, 1x optional intake in top front (get a filter for this), 1x exhaust in back, 1x exhaust in top back.

H440 Airflow: Large tower cooler

I would recomend 2x front intake at top 2 slots, and 1x rear exhaust, optional top back exhaust and top middle intake (get a filter for this)

H440 Airflow: Stock cooler

I would recomend 2x front intake in top 2 positions, 1x rear exhaust, optional top back 2 exhaust, and optional front bottom intake.

H440 Airflow: 240mm AIO Liquid cool

I would recomend the radiator be mounted on the top back as exhaust, front top 2 slots intake, rear intake (get a filter for this) and optional front bottom intake.

S340 Airflow: 240/280MM AIO Liquid cool

I would recommend that the rad goes in the front as intake, with 1 rear exhaust, and no top fan.

S340 Airflow: 120MM AIO Liquid Cool

I would recommend dual front intake, of 120 or 140mm fans, and have the rad as rear exhaust. DO NOT occupy the top fan slot.

S340 Airflow: Tower Heatsink

Fill the front 2 intake fans first, then the rear. Leave the top empty.

Enthoo Luxe/Pro Airflow: Tower Heatsink

First, fill the front with either a 200mm fan or 2 120mm or 140mm fans.
Then, Occupy the rear fan slot with an exhaust fan.
If wanted, occupy the bottom with an intake, and the rear most top fan slot with an exhaust.
The other two top fan slots should be left unused, or optional intakes.

Enthoo Luxe/Pro Airflow: Single 120mm AIO

First, occupy the front with a 200mm or dual 120/140mm intakes.
Then, put the radiator in the rear of the case, as exhaust. Then, if wanted, occupy the bottom with an intake. If you want, occupy the rear most top fan slot with an exhaust. I would not recommend it tho.

Enthoo Luxe/Pro Airflow: 240/280mm AIO

First, occupy the front with 200mm or dual 120/140mm intakes.
Then, occupy the top 2 most rear fan slots with the radiator set as exhaust.
Then, occupy the rear with an intake, and if you want, bottom with intake.

Impact Of GPU, Side Fan, and PSU on airflow:
Adding any large object to a case will impact airflow, usually for the worse.
To eliminate any of this, have the PSU facing down, unless you have no vent, or have thick carpet. This will take PSU airflow out of the picture.
GPU's will mess up air flow.
If you have ideal, front to back airflow, a blower style will impact it less.
For a more standard airflow case, just get one that performs well.
Side fans are a large debate.
It all depends on your case and GPU.
You would have to see what works for you.

 

SFF Cooling

Small form factor cases are on the rise, and they always are a challenge to cool. New designs are very unique, so each case will be very different to cool. A general rule of thumb is that a blower style GPU will be better, but this is not always the case. With cases such as the RVZ01/2, the separate GPU chamber allows the GPU to not effect the CPU's airflow. IN cases like this, and aftermarket design would work out fine.

Ask any questions, and Ill add the answers to the OP here, so this can become a database of air info.

[MegaDave91]

Many people dont know this. 

 

Not sure how true that is, but I'm sure there are a few out there.

 

A case without filtered intakes is a potential deal breaker for me, unless I can overlook it because of other features and just make my own filters.

[spwath]

Not sure how true that is, but I'm sure there are a few out there.

Yeah maby I was exaggerating but I don't want people to think wrong

[SparkySamZa]

so what does CFM stand for then ? never got that 

[MegaDave91]

so what does CFM stand for then ? never got that 

Cubic feet per minute

[spwath]

so what does CFM stand for then ? never got that 

Cubic feet per minute

 

hmm you got me

 

Cubic feet per minute

 

[daemonowner]

You should talk about m³/h 

[spwath]

You should talk about m³/h 

DO things use cubic meter per hour? Ill put it down

[daemonowner]

I've seen it as an alternative for cfm, possibly to confuse customers into overestimating a fans performance.

 

http://www.scythe-eu.com/en/products/fans/gentle-typhoon-120-mm.html

Here is an example of m³/h being used.

[SparkySamZa]

thanks for clearing that one up i always did wonder what it meant . 

[SparkySamZa]

has anyone got a hold of benchmarks of the new industrial noctua PPC fans and noise levels to CFM comparison ??

[Internet Swag]

Okay, here's one.

 

Do you need to supplement additional CFM (adding another intake fan) when you insert large objects into your case such as a big CPU cooler in a small case? 

[spwath]

Okay, here's one.

Do you need to supplement additional CFM (adding another intake fan) when you insert large objects into your case such as a big CPU cooler in a small case?

Most of the time no, you may need to change where fans are tho, i'll explain in depth with diagrams when I'm home later today

[Internet Swag]

bump

[spwath]

bump

started answering youre question in depth in OP will finihs later today

[HappyChubbs]

DO things use cubic meter per hour? Ill put it down

 

Companies will either use CFM (Standard - Corsair) or m3/h (Metric - Noctua).

 

1 CFM = 1.70 m3/h

 

Side note, Static pressure is measured in mmH20.

[Guest]

Side intake fans ruin the looks of a case 

[spwath]

Side intake fans ruin the looks of a case

Depends on if it's on the widow like the c70.

[spwath]

Added set up 2 and 3, will add small rigs soon

[The_Strict_Nein]

So my current set up looks something like this

 

 

According to you, I should change the fan closest to the front at the top to intake, correct?

 

Also, should I move the 120mm static pressure fan at the bottom of my case to the front and put the 140mm low static pressure fan into the bottom?

[spwath]

So my current set up looks something like this

 

fans.jp

 

According to you, I should change the fan closest to the front at the top to intake, correct?

 

Also, should I move the 120mm static pressure fan at the bottom of my case to the front and put the 140mm low static pressure fan into the bottom?

I would do that yes. Either make the top one intake or remove it. And yeah, switch thoes 2

[Faa]

You should talk about m³/h 

50 CFM comes down to (1.43m³/m) * 60 gives us 80m³/h orsomething.

 

[daemonowner]

Side intake fans ruin the looks of a case 

And they often don't come with adequate dust filters.

[spwath]

And they often don't come with adequate dust filters.

Its called carbon filters from air purifiers. My case:

This is my old set up by the way, looks better now

[HappyChubbs]

If you want to use a cheap air filter, fabric softener sheets are pretty useful.  They also make the case smell pretty.