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Delta fan back to back ?. Good idea ?

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ºSåmuråiº

Registered
Joined
Jun 20, 2001
I am using the GlobalWin WBK38. As my delta fan is blowing towards the heatsink, I was thinking of getting another Delta which blows at the same direction and fix it on top of the Delta fan on my heatsink. Do you think it is a good idea ?.

By the way, is Thermoengine a much better heatsink than WBK38 ?
 

Paiynn

Member
Joined
Jul 8, 2001
Two fans on top of each other are still only going to push 38cfm as compared to two fans side by side which would be moving different air.
 

JaY_III

Senior of BX
Joined
Dec 17, 2000
your idea will work.
BUT
read BUT
the fan on top has to spin the other direction as the fan on the bottom.
ex:
bottom fan spins clockwise
top fan spins counter
 

The Coolest

Senior Member
Joined
Jul 29, 2001
jay (Jul 30, 2001 02:03 p.m.):
your idea will work.
BUT
read BUT
the fan on top has to spin the other direction as the fan on the bottom.
ex:
bottom fan spins clockwise
top fan spins counter

Can u please tell me how is it working with two different air directions,
cause I tried the 1 fan on top of the other already and it just got worse
 
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Location
santacruz county, ca
The Coolest (Jul 30, 2001 02:24 p.m.):
jay (Jul 30, 2001 02:03 p.m.):
your idea will work.
BUT
read BUT
the fan on top has to spin the other direction as the fan on the bottom.
ex:
bottom fan spins clockwise
top fan spins counter

Can u please tell me how is it working with two different air directions,
cause I tried the 1 fan on top of the other already and it just got worse

I believe when the 2 fans are spinning in diffrent direction their will be a vacume effect. Although I believe its pretty difficult and its loud.
 
OP
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ºSåmuråiº

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Jun 20, 2001
I read on the reviews and they say the black anodised Thermoengine with 7K delta performs better than WBK38 so I dont know how true it is. I have an extra 7K delta which I dont know where to fix at to get my CPU cooler. It seems like putting a fan at the side of the heatsink helps out a little but I am yet to try it. Any idea guys ?
 

Bobby Manus

Member
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Dec 17, 2000
Location
Southern California
Ive also seen a few heatsinks with mini fans on the side and I think its jut silly. The whole design of a heatsink is to get the hot air up and away from the cpu. Just look at there designs! Usually highly conductive metals (like copper) and with many "fins" or "pins". This is just a great way to get the hot air to rise. Having your delta facing the wrong way in my opinion is silly, its like your fighting with your heatsink. And puting a small fan on the side, same concept... Instead of the heat going up threw the conductive metal to the fan to be blown away its going to have a fan blowing it sideways. This would have an even less effect if you have the fan on top of the heatsink facing down, you would just have a big air colision inbetween the pins of your heatsink. What I recomend is turning your delta the other way, and if you want, try puting a fan on the side but make sure its blowing away from the heatsink. And also make sure you point the fan on the side to the nearest exhuast fan, and definitly not towards something important like ram or pci cards. This would just be blowing hot air from one place to the other.
 

AmbientFiction

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It would work like this see figure 1. Note: the Heatsink would have to have fins or an open flow through. The top fans needs to push down and the side fan needs to push to the exit port. Using something like Delta 60mm high outputs or maybe even an 80mm this would be a very good cooling system.
 

Bobby Manus

Member
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Dec 17, 2000
Location
Southern California
Yes I'm seing your vision... add an exhuast fan on the other side... Lil more suction. But it seems like you will be competing with the fan on top of the heatsink. Im sure somone has tried this and has made me a nice chart with pretty flowers for me to quickly see which is th best... anyone got a link?
 

AmbientFiction

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It would work all its doing is pushing twice the air on to the heatsink I don't see any compitation air wise unless its the fact that you need more air flow comeing into the case. Like say an open 5 1/2" drive bay the lowest one you have or in line with the cpu and take a hard drive cooler install it and turn that sucker on. that would give the air flow that you need.
 

cjtune

Member
Joined
Dec 18, 2000
AmbientFiction (Jul 30, 2001 11:16 p.m.):
It would work all its doing is pushing twice the air on to the heatsink I don't see any compitation air wise unless its the fact that you need more air flow comeing into the case. Like say an open 5 1/2" drive bay the lowest one you have or in line with the cpu and take a hard drive cooler install it and turn that sucker on. that would give the air flow that you need.

Axial fans produce seriously less airflow with increasing impedence to the airflow path. Note that both of your fans need to push (together) twice the amount of air through an exit 1/2 as big as with just one fan alone. By itself, one fan on your HS may output 20cfm, but together in your configuration they may just output 12+12=24cfm -diminishing returns for parallel flow. This is why some ppl consider stacking fans to produce more pressure (in series config) to fight the impedences, but this stacking cannot be realistically done on the normal DC fans we use, one on top of another, due to the direction of rotation and blade design -in essence, the two fans must be designed for each other.

Do you have any temperature measurements to test out your fan placement method?
 

Wa11y

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My understanding is that you want the fan blowing ON the heatsink. Ever put your hand behind a fan? Doesn't move as much air as the front side does. Because the output focuses the air out, while the input just grabs air from an endless supply, so it's not very focused. So it makes sense that if you want the air to move away from the heat sink, you'd have it blow instead of suck. That way it gets blown out the sides of the heatsink, instead of being pulled out the top. This is where case airflow comes into play. The fan on the heatsink only cools the heatsink. The case fans then take the air that is disbursed by the fan on the heatsink, and move it out of the case altogether, drawing in more cool air.

That's also why I feel negative air pressure (more air being sucked out than being sucked in) is better, and why you want the intake fans at the bottom front of your case, and the output fans at the top back of your case.
 

AmbientFiction

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cjtune (Jul 31, 2001 05:38 a.m.):
AmbientFiction (Jul 30, 2001 11:16 p.m.):
It would work all its doing is pushing twice the air on to the heatsink I don't see any compitation air wise unless its the fact that you need more air flow comeing into the case. Like say an open 5 1/2" drive bay the lowest one you have or in line with the cpu and take a hard drive cooler install it and turn that sucker on. that would give the air flow that you need.

Axial fans produce seriously less airflow with increasing impedence to the airflow path. Note that both of your fans need to push (together) twice the amount of air through an exit 1/2 as big as with just one fan alone. By itself, one fan on your HS may output 20cfm, but together in your configuration they may just output 12+12=24cfm -diminishing returns for parallel flow. This is why some ppl consider stacking fans to produce more pressure (in series config) to fight the impedences, but this stacking cannot be realistically done on the normal DC fans we use, one on top of another, due to the direction of rotation and blade design -in essence, the two fans must be designed for each other.

Do you have any temperature measurements to test out your fan placement method?
I tell ya what I am going to be working on a massive air cooling project in a few months I'll try it out then. Although I wasn't talking about doing this with little fans I was talking about 68 cfm deltas which would push enough air. So I am still trying to figure out why your trying to say that its not going to work.
 
OP
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ºSåmuråiº

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Jun 20, 2001
I am actually trying to cool down things in my casing. Im currently running my PC with one side open.