Overclock.net › Forums › Cooling › Air Cooling › Best 120mm fans for air cooling
New Posts  All Forums:Forum Nav:

# Best 120mm fans for air cooling - Page 2

Regarding surface area, three 140mm fans cover more than four 120mm fans.
140mm x 140mm x 3 = 58,800mm² surface area for three 140mm fans
120mm x 120mm x 4 = 57,600mm² surface area for four 120mm fans

But that's not the whole picture, so why stop there? Let's assume the average radius of a 140mm fan is 66mm, and the average radius of a 120mm fan is 56mm. Let's also assume the average radii of the fan hubs are 28mm and 22mm, respectively. Using a rough conversion of 3.14 for ᴨ, we'll get:
3.14 x (66mm)² = 13,678mm² outer 140mm fan area
3.14 x (28mm)² = 2,462mm² inner 140mm fan area
13,678mm² - 2,462mm² = 11,216mm² maximum planar 140mm fan blade surface area*

3.14 x (56mm)² = 9,847mm² outer 120mm fan area
3.14 x (22mm)² = 1,520mm² inner 120mm fan area
9,847mm² - 1,520mm² = 8,327mm² maximum planar 120mm fan blade surface area*

11,216mm² x 3 = 33,648mm² planar fan blade surface area for three 140mm fans*
8,327mm² x 4 = 33,308mm² planar fan blade surface area for four 120mm fans*
*The maximum planar fan blade surface area can be more or less than the actual fan blade surface area depending on the number, size, and shape of the blades.

Of course, all of that only means so much in the face of blade design. But who says we have to be finished already?
If we assume the 140mm fan spins at 1200rpm and the 120mm fan spins at 1400rpm, we can make a simple estimation of the average linear velocity of the fan blades using ᴨ/30 to convert rpm to rad/s:
1200rpm x 66mm x ᴨ/30 = 8,290mm/s maximum 140mm fan blade velocity
1200rpm x 28mm x ᴨ/30 = 3,517mm/s minimum 140mm fan blade velocity
(8,290mm/s + 3,517mms) / 2 = 5,904mm/s 140mm fan blade average linear velocity

1400rpm x 56mm x ᴨ/30 = 8,206mm/s maximum 120mm fan blade velocity
1400rpm x 22mm x ᴨ/30 = 3,224mm/s minimum 120mm fan blade velocity
(8,206mm/s + 3,224mm/s) / 2 = 5,715mm/s 120mm fan blade average linear velocity

We're on a roll. Let's keep going.
Since our math isn't dirty enough already, if we assume that our linear velocity over a given area can convert directly into airflow at a consistent ratio relative to speed, say 1/2 cubic meter per m/s per m², we can arrive at:
5,904mm/s x 33,648mm² x 3600s/1hr x 1m³/1,000,000,000mm³ x 1/2 = 358m³/h for three 140mm fans
5,715mm/s x 33,308mm² x 3600s/1hr x 1m³/1,000,000,000mm³ x 1/2 = 343m³/h for four 120mm fans

You're being really short-sighted if that's the only criteria you're using to determine what's better for you. I had to make a lot of assumptions that aren't inherently accurate, and fan design and rotational speed can have a much greater impact than some definition of "surface area."

Since you won't give us any other information about your system or judging criteria to go by other than "best-performing," I'm forced to recommend four of the 4114 N/2H8P by ebm-papst for a total of 2,277m³/h tornado-inducing airflow and 480W of blackout-causing power consumption.
Edited by gftgy - 10/8/15 at 11:53am
ROFL :
applaud:
danielhowk
Our bark is much worse than our bite.
Tell us what you have and we will help you sort it out.
Quote:
Originally Posted by doyll

A 120mm fan has approx 100sq cm of airflow area, meaning 4x 120mm fans have 400sq cm of airflow area
A 140mm fan has approx 140sq cm of airflow area, meaning 3x 140mm fans have 420sq cm of airflow area

But you still have not told us what your system is, and without knowing all the details it is impossible to know what fans will be best for your application. Even more important is their placement to achieve optimum airflow. You might find "Ways to Better Cooling" link in my sig helpful. 1st post is index, click on topics of interest to see them.

Quote:
Originally Posted by ciarlatano

Actually.....120x120x4 = 57,600 sq mm, while 140x140x3 = 58,800 sq mm of surface area. The fans aren't one dimensional.

You also need to realize that putting a fan in every possible location is not necessarily the answer to better airflow, especially when those spots are designed for radiators and not fans in an air cooled case. Typically completely filling a Primo in an air cooled scenario makes a total airflow mess with a lot of noise.

But....since you refuse to tell us what you are trying to accomplish, and with what components, it is impossible to recommend anything to you.

Quote:
Originally Posted by gftgy

Regarding surface area, three 140mm fans cover more than four 120mm fans.
140mm x 140mm x 3 = 58,800mm² surface area for three 140mm fans
120mm x 120mm x 4 = 57,600mm² surface area for three 120mm fans

But that's not the whole picture, so why stop there? Let's assume the average radius of a 140mm fan is 66mm, and the average radius of a 120mm fan is 56mm. Let's also assume the average radii of the fan hubs are 28mm and 22mm, respectively. Using a rough conversion of 3.14 for ᴨ, we'll get:
3.14 x (66mm)² = 13,678mm² outer 140mm fan area
3.14 x (28mm)² = 2,462mm² inner 140mm fan area
13,678mm² - 2,462mm² = 11,216mm² maximum planar 140mm fan blade surface area*

3.14 x (56mm)² = 9,847mm² outer 120mm fan area
3.14 x (22mm)² = 1,520mm² inner 120mm fan area
9,847mm² - 1,520mm² = 8,327mm² maximum planar 120mm fan blade surface area*

11,216mm² x 3 = 33,648mm² planar fan blade surface area for three 140mm fans*
8,327mm² x 4 = 33,308mm² planar fan blade surface area for four 120mm fans*
*The maximum planar fan blade surface area can be more or less than the actual fan blade surface area depending on the number, size, and shape of the blades.

Of course, all of that only means so much in the face of blade design. But who says we have to be finished already?
If we assume the 140mm fan spins at 1200rpm and the 120mm fan spins at 1400rpm, we can make a simple estimation of the average linear velocity of the fan blades using ᴨ/30 to convert rpm to rad/s:
1200rpm x 66mm x ᴨ/30 = 8,290mm/s maximum 140mm fan blade velocity
1200rpm x 28mm x ᴨ/30 = 3,517mm/s minimum 140mm fan blade velocity
(8,290mm/s + 3,517mms) / 2 = 5,904mm/s 140mm fan blade average linear velocity

1400rpm x 56mm x ᴨ/30 = 8,206mm/s maximum 120mm fan blade velocity
1400rpm x 22mm x ᴨ/30 = 3,224mm/s minimum 120mm fan blade velocity
(8,206mm/s + 3,224mm/s) / 2 = 5,715mm/s 120mm fan blade average linear velocity

We're on a roll. Let's keep going.
Since our math isn't dirty enough already, if we assume that our linear velocity over a given area can convert directly into airflow at a consistent ratio relative to speed, say 1/2 cubic meter per m/s per m², we can arrive at:
5,904mm/s x 33,648mm² x 3600s/1hr x 1m³/1,000,000,000mm³ x 1/2 = 358m³/h for three 140mm fans
5,715mm/s x 33,308mm² x 3600s/1hr x 1m³/1,000,000,000mm³ x 1/2 = 343m³/h for four 120mm fans

You're being really short-sighted if that's the only criteria you're using to determine what's better for you. I had to make a lot of assumptions that aren't inherently accurate, and fan design and rotational speed can have a much greater impact than some definition of "surface area."

Since you won't give us any other information about your system or judging criteria to go by other than "best-performing," I'm forced to recommend four of the 4114 N/2H8P by ebm-papst for a total of 2,277m³/h tornado-inducing airflow at 480W at 48V of blackout power consumption.

Quote:
Originally Posted by doyll

ROFL :
applaud:
danielhowk
Our bark is much worse than our bite.
Tell us what you have and we will help you sort it out.
no problem because i havent got my rig yet thats why i didnt post. but heres my rig im buying
asus hero z170 , intel 6700k , samsung ssd 850 evo , planning to buy samsung 950 pro when its release , super flower 850 w , 980ti msi lightning , noctua d15
Quote:
Originally Posted by danielhowk

no problem because i havent got my rig yet thats why i didnt post. but heres my rig im buying
asus hero z170 , intel 6700k , samsung ssd 850 evo , planning to buy samsung 950 pro when its release , super flower 850 w , 980ti msi lightning , noctua d15
Okay, and what case are you going to put it all in?
Quote:
Originally Posted by danielhowk

im using phanteks enthoo primo

He actually said that one.
Quote:
Originally Posted by doyll

Quote:
Originally Posted by danielhowk

no problem because i havent got my rig yet thats why i didnt post. but heres my rig im buying
asus hero z170 , intel 6700k , samsung ssd 850 evo , planning to buy samsung 950 pro when its release , super flower 850 w , 980ti msi lightning , noctua d15
Okay, and what case are you going to put it all in?

Dude... That was, like, the only thing he mentioned.

I am subscribing to this thread for.. ah, yes, the flow of knowledge.
 MEGATRON (24 items) GIGATRON (10 items)
CPUMotherboardGraphicsGraphics
Intel Core i5-3570K @ 4.8/1.32V | Hammer&Vice'd ASUS Sabertooth Z77 PowerColor R9 290 PowerColor R9 290
RAMHard DriveHard DriveCooling
Samsung MV-3V4G3D/US 4x4GB kit @ 2200MHz 9-10-1... 2x Western Digital Caviar Black 1TB RAID 0 Samsung 840 Evo 250GB 2xAquacomputer Kryographics Hawaii Nickel/Acrylic
CoolingCoolingCoolingCooling
XSPC Rasa Swiftech MCP-655 Vario Aquacomputer Aqualis 450mm w/ nano & Pump top 2x XSPC RX360; 1x XSPC RS360; 1x Alphacool ST 1...
CoolingOSMonitorMonitor
EK-Vardar F4-120 8.1 x64; Ubuntu 14.10 Dell U2412M Dell U2412M
MonitorMonitorKeyboardPower
Dell U2312H BenQ XL2411Z KBC Poker II MX Clears SeaSonic SS-850AM
Thermaltake Core X9 Mionix AVIOR 7000 Razer Goliathus Aune T1 -> Yamaha A-720 -> Sennheiser HD650 | S...
CPUCPUMotherboardGraphics
Intel Xeon E5-2650 v4 @ 2.00GHz Intel Xeon E5-2650 v4 @ 2.00GHz SuperMicro X10DAL-i nay
RAMHard DriveCoolingOS
2x8GB (for now) Kingston DDR4 @ 2133MHz/C16 Samsung 840 120GB EK-Vardar F4 on an Arctic Freezer i11 Ubuntu Server 16.04
PowerCase
SeaSonic SS850-AM overrated
 MEGATRON (24 items) GIGATRON (10 items)
CPUMotherboardGraphicsGraphics
Intel Core i5-3570K @ 4.8/1.32V | Hammer&Vice'd ASUS Sabertooth Z77 PowerColor R9 290 PowerColor R9 290
RAMHard DriveHard DriveCooling
Samsung MV-3V4G3D/US 4x4GB kit @ 2200MHz 9-10-1... 2x Western Digital Caviar Black 1TB RAID 0 Samsung 840 Evo 250GB 2xAquacomputer Kryographics Hawaii Nickel/Acrylic
CoolingCoolingCoolingCooling
XSPC Rasa Swiftech MCP-655 Vario Aquacomputer Aqualis 450mm w/ nano & Pump top 2x XSPC RX360; 1x XSPC RS360; 1x Alphacool ST 1...
CoolingOSMonitorMonitor
EK-Vardar F4-120 8.1 x64; Ubuntu 14.10 Dell U2412M Dell U2412M
MonitorMonitorKeyboardPower
Dell U2312H BenQ XL2411Z KBC Poker II MX Clears SeaSonic SS-850AM
Thermaltake Core X9 Mionix AVIOR 7000 Razer Goliathus Aune T1 -> Yamaha A-720 -> Sennheiser HD650 | S...
CPUCPUMotherboardGraphics
Intel Xeon E5-2650 v4 @ 2.00GHz Intel Xeon E5-2650 v4 @ 2.00GHz SuperMicro X10DAL-i nay
RAMHard DriveCoolingOS
2x8GB (for now) Kingston DDR4 @ 2133MHz/C16 Samsung 840 120GB EK-Vardar F4 on an Arctic Freezer i11 Ubuntu Server 16.04
PowerCase
SeaSonic SS850-AM overrated
Quote:
Originally Posted by danielhowk

no problem because i havent got my rig yet thats why i didnt post. but heres my rig im buying
asus hero z170 , intel 6700k , samsung ssd 850 evo , planning to buy samsung 950 pro when its release , super flower 850 w , 980ti msi lightning , noctua d15

So, just to be sure - NO mechanical drives?

Your "dilemma" really couldn't be simpler, given that the 140SP included with the Primo are one of the better performing 140mm in that application. You are totally overthinking it, and are pre-disposed to thinking that changing the fans will actually be beneficial, or that more fans will do anything other than add noise.

1. Remove the HDD cages
2. Add a second 140SP on the bottom as intake.
3. Add a second 140SP on the top for exhaust (this is pretty much purely for aesthetics).

If you want LEDs, get two 140SP with LED and put them up top, and use the two non-LED on the bottom.
Quote:
Originally Posted by fragamemnon

Dude... That was, like, the only thing he mentioned.

I am subscribing to this thread for.. ah, yes, the flow of knowledge.
Oops. My bad. I post on so many thread it's hard to keep all the info straight.
Quote:
Originally Posted by ciarlatano

So, just to be sure - NO mechanical drives?

Your "dilemma" really couldn't be simpler, given that the 140SP included with the Primo are one of the better performing 140mm in that application. You are totally overthinking it, and are pre-disposed to thinking that changing the fans will actually be beneficial, or that more fans will do anything other than add noise.

1. Remove the HDD cages
2. Add a second 140SP on the bottom as intake.
3. Add a second 140SP on the top for exhaust (this is pretty much purely for aesthetics).

If you want LEDs, get two 140SP with LED and put them up top, and use the two non-LED on the bottom.
what ciarlatano said.
I've found the PH-F140SP fans to be quite good. The stock fans do just fine with 2x front intake, 2x bottom intake and 1x rear exhaust. The back of case has lots of venting and airflow is great.

I do have case raised on a caster base both for better airflow to bottom fans and easy access. The case venting to bottom fans is very limited .. at best only enough airflow area for a single fan, so raising it up 35-45mm makes a big difference in both airflow as well as lowering noise levels.
Quote:
Originally Posted by doyll

Okay, and what case are you going to put it all in?

Quote:
Originally Posted by gftgy

He actually said that one.

Quote:
Originally Posted by fragamemnon

Dude... That was, like, the only thing he mentioned.

I am subscribing to this thread for.. ah, yes, the flow of knowledge.

Quote:
Originally Posted by ciarlatano

So, just to be sure - NO mechanical drives?

Your "dilemma" really couldn't be simpler, given that the 140SP included with the Primo are one of the better performing 140mm in that application. You are totally overthinking it, and are pre-disposed to thinking that changing the fans will actually be beneficial, or that more fans will do anything other than add noise.

1. Remove the HDD cages
2. Add a second 140SP on the bottom as intake.
3. Add a second 140SP on the top for exhaust (this is pretty much purely for aesthetics).

If you want LEDs, get two 140SP with LED and put them up top, and use the two non-LED on the bottom.

Quote:
Originally Posted by doyll

Oops. My bad. I post on so many thread it's hard to keep all the info straight.
what ciarlatano said.
I've found the PH-F140SP fans to be quite good. The stock fans do just fine with 2x front intake, 2x bottom intake and 1x rear exhaust. The back of case has lots of venting and airflow is great.

I do have case raised on a caster base both for better airflow to bottom fans and easy access. The case venting to bottom fans is very limited .. at best only enough airflow area for a single fan, so raising it up 35-45mm makes a big difference in both airflow as well as lowering noise levels.
would noctua A-14 pwm be better than PH-F140SP fans?
im not sure to go with Be quiet Silent Wings 2 , Gentle Typhoon or Noctua A-14 pwm.
as it is easily found near my store. what do you guys think
Quote:
Originally Posted by danielhowk

would noctua A-14 pwm be better than PH-F140SP fans?
im not sure to go with Be quiet Silent Wings 2 , Gentle Typhoon or Noctua A-14 pwm.
as it is easily found near my store. what do you guys think

The NF-A14 are not discernably better in this application.
The Silent Wings 2 are quieter, but don't move nearly as much air.
The GT's are 120....and while great 120mm fans, won't move as much air at like noise levels.

Making changes for the sake of making changes won't necessarily improve what you already have. It will simply make getting the same result more expensive.
New Posts  All Forums:Forum Nav:
Return Home
Back to Forum: Air Cooling
• Best 120mm fans for air cooling
Overclock.net › Forums › Cooling › Air Cooling › Best 120mm fans for air cooling