Static pressure vs. airflow fans

[KHIT]

Hi
I'm currently looking at getting a fan for the front of my NZXT Phantom(Original) and I'm wondering if a static pressure or a airflow fan would suit my system best. I'm looking at getting some CORSAIR AF or SP series fan as I've heard a lot of possitive response to these fans. Are there any quiet fans in either 120mm or 140mm you can recommend other than the ones from corsair. Would Noctua be a better choice? And last but not least, should I use pressure or airflow fans for the front?

[phoen]

For case fans you need good airflow, static pressure fans is for heatsink/rad.

[Bo$$]

140mm are generally quieter as they spin more slowly

[Jack1n]

Is it the lower front fan that blows air on the hard drives?,if so it might be better to get static pressure because your drive bay is pretty populated.

[qubit]

Originally Posted by KHIT

Hi
I'm currently looking at getting a fan for the front of my NZXT Phantom(Original) and I'm wondering if a static pressure or a airflow fan would suit my system best. I'm looking at getting some CORSAIR AF or SP series fan as I've heard a lot of possitive response to these fans. Are there any quiet fans in either 120mm or 140mm you can recommend other than the ones from corsair. Would Noctua be a better choice? And last but not least, should I use pressure or airflow fans for the front?

You're confusing terms here.

There's no difference between static pressure, pressure or air flow.

All fans work the same way and generate air pressure by moving air ie air flow.

All you're interested in is how much air flow the fan generates at what noise level. Generally, people like quiet fans so that means the largest fan that you can get, made by a good quality manufacturer such as Noctua etc.

[de.das.dude]

^ you high?

more static pressure fans = better suited for heatsinks and radiators, and things that usually offer a lot of resistance to the fans.

[Jack1n]

Originally Posted by de.das.dude

^ you high?

more static pressure fans = better suited for heatsinks and radiators, and things that usually offer a lot of resistance to the fans.

Such as an HDD cage with 3 HDD's in it.

[RejZoR]

Originally Posted by qubit

You're confusing terms here.

There's no difference between static pressure, pressure or air flow.

All fans work the same way and generate air pressure by moving air ie air flow.

All you're interested in is how much air flow the fan generates at what noise level. Generally, people like quiet fans so that means the largest fan that you can get, made by a good quality manufacturer such as Noctua etc.

Erm, no? You need static pressure when you have to push a lot of air through tight space like heatsink or water cooler radiator. Air flow is needed when you just need to push a lot of unrestricted air.

Be aware that air essentially behaves like liquid. Without pressure, it will slow down significantly through tight spaces.

[KHIT]

Thanks for your replies. I want a fan for the front of the case. The one that is not included with the case.
so this means that a static pressure fan is the one

[erocker]

Originally Posted by KHIT

Thanks for your replies. I want a fan for the front of the case. The one that is not included with the case.
so this means that a static pressure fan is the one

No, it would mean that you want the airflow version. The static pressure fans are for radiators and heatsinks.

[n3rdf1ght3r]

The 140mm would be quieter than the 120mm because it can spin at a lower RPM but still push the same amount of air. You would normally use an airflow optimised fan for the front of a case but if you happen to have alot of hard drives, you might want to go towards a pressure optimized fan. Noctua's are great fans and very silent. If you are going for the corsairs, I would recommend the quiet editions because a properly optimized gaming rig should be silent.

[MxPhenom 216]

Originally Posted by qubit

You're confusing terms here.

There's no difference between static pressure, pressure or air flow.

All fans work the same way and generate air pressure by moving air ie air flow.

All you're interested in is how much air flow the fan generates at what noise level. Generally, people like quiet fans so that means the largest fan that you can get, made by a good quality manufacturer such as Noctua etc.

Is all i have to say about that statement. LOL

[erixx]

Reminds me discussions about what is better, if torque or horsepowser, or twins/inlines in motorcycle forums (and who knows, even cage forums...

[D4S4]

very similar to tq/hp, i'm amazed so many people still don't know rpm*tq=hp.

anyhow, common sense ftw - you have a tight case grill with small drilled holes, use high static pressure fan. you have a wide spaced case grill (or you can cut it out completely), use high flow fan.

[phanbuey]

Intake fans, rad fans, and heatsink fans should have good static pressure, exhaust fans can sacrifice a bit for airflow, especially in a positive pressure case (where you have more intake than exhaust).

[qubit]

Originally Posted by MxPhenom 216

Is all i have to say about that statement. LOL

to you too and the rest of you numpties taking potshots at me.

More airflow gives you more pressure. End. You so-called experts should understand this.

[Chevalr1c]

Much air flowing trough large spaces: high flow & low pressure.
Much air flowing through small(er) spaces: high flow & high pressure.

Air flow is the gaseous equivalent to the ampère and (static) pressure is the equivalent to the Volt. One could also compare the matter to water (or any other fluid) going trough a wide versus narrow tube.

Please correct me if I am wrong, physics class is too long ago for me as it seems.

[erixx]

that is all right and nice, but the difference that matters is that the high pressure fan is just a better (aka stronger) fan that maintains its air productions even if there are obstacles. The high speed fan is supposed to loose it's speed in adversity...

Feel free to correct me...

[sneekypeet]

Originally Posted by erixx

that is all right and nice, but the difference that matters is that the high pressure fan is just a better (aka stronger) fan that maintains its air productions even if there are obstacles. The high speed fan is supposed to loose it's speed in adversity...

Feel free to correct me...

That's the way it works. High flow does not equal high pressure.

[qubit]

Originally Posted by sneekypeet

That's the way it works. High flow does not equal high pressure.

It's ultimately the speed of the air that creates the pressure, which is all I'm saying and people don't seem to understand. Hence, the faster the air goes, the more pressure, regardless of fan size. A bigger fan simply moves more air.

Also, asking for a "static pressure" fan like the OP does is nonesensical and I tried to expain this to him, as everyone gets confused otherwise, especially him. It's as dumb as asking for a car with "speed". They've all got it, or they wouldn't go anywhere! The real question is whether one should buy a fast car or a slow car and the tradeoffs between them. Same with the pressure rating of a fan.

[sneekypeet]

Explain a Noctua fan to me then! They break you rule of speed = pressure, because they are one of the lowest in speed, but averagely highest in static pressure.

You need to understand that a lot of high speed fans, once impeded, dont have the pressure needed to force the air around or through the obstruction, even if the RPM still says 2000, you aren't getting the full air flow or static pressure in the average fan. Fans with Static pressure have the "torque/ass" it needs to keep supplying close to the same CFM and air flow specs, even when impeded upon

[qubit]

Originally Posted by sneekypeet

Explain a Noctua fan to me then! They break you rule of speed = pressure, because they are one of the lowest in speed, but averagely highest in static pressure.

The angle of the fan blades, their overall design and how close they are to the outer casing without touching it greatly affects the efficiency of a fan. Hence, if you compared the best fan with the poorest at the same revs using an air flow meter you would see the air move faster with the better fan (and likely with less buzzing, whining or other unpleasant noises, too). It therefore would have higher pressure/static pressure (same thing).

[sneekypeet]

I think you need to get an airflow meter, and set up a tube full of water to comprehend what I am saying. What I am saying is the truth, I have no reason to BS you!

All I am stating is that while your analogies may make sense, when you test these fans appropriately, fans with high static pressure ratings tend to keep that mark. Those geared for higher RPM with a low static pressure rating are going to lose both air flow and pressure as you add things in front of it (such as that tube of water).

[erocker]

Originally Posted by qubit

The angle of the fan blades, their overall design and how close they are to the outer casing without touching it greatly affects the efficiency of a fan. Hence, if you compared the best fan with the poorest at the same revs using an air flow meter you would see the air move faster with the better fan. It therefore would have higher pressure/static pressure (same thing).

You're forgetting the motor and how resistance plays a part in its performance.

Example: a weaker motor that spins fast can produce a lot of airflow. Impede the airflow by placing a radiator in front of the the weaker motor will not work very well. A more powerful motor will not be hindered so much by resistance resulting in higher airflow during situations where higher static pressure is needed.

[sneekypeet]

bearings, bushings, pitch, angle, shape, texture, additional features in a frame such as dimples or step down areas where the air first rubs against the frame, there are literally tons of ways to change the performance of a fan.

All I am getting at is that there are high static pressure fans for a reason, it isn't just a marketing gimmick as Qubit is implying.