View Full Version : My latest air cooling escapade
Putting squirrel cage fans on heatsinks isn't all that revolutionary; people have done it before, both with their own custom setups, as well as off-the-shelf HSFs such as the Aero 7 from Coolermaster.
But, I don't think anyone has done anything quite like this yet... ;)
---NOTE---
The heatsink in the above pics is an SLK-800; that should give you an idea of how big this thing is
----END NOTE---
This is basically just the test rig... it's not very polished (ok, so it's not polished at all...), but it's not meant to be; I just want to see how well it works.
The fans are Sunon PB1212PLB1 squirrel cage units; they flow 40.2CFM @ 56.5dBA. Compared to traditional axial fans, that's an awful noise/airflow ratio, especially for a 120x32mm fan; however, squirrel cage (centrifugal) fans have a distinct advantage over axial fans: they can produce far, far higher air pressures than axial fans can, and they deal with backpressure very well.
Because of this, it should make them ideal for forcing air into the fins of today's ultra-thin fin heatsinks (which may be why coolermaster is using them).
So, if this works, I'll build a better mounting bracket. But for now, I just want to find out if it works...
I'll test it using my SLK-900A though, not the SLK-800 in the pics.
Well, if you wanted to hand me that roll of duct tape over there, I'd appreciate it... :D
I like the way you have the blower concentrated on the surface of slk fins ...a 70 mm fan can't even do that without some sorta adapter which I have never seen..
But because of the extra large size of the cages this looks like an inefficent way to blow air thru the fins efficiently! lol
I can picture the case side door now ...huge power bulge like on a funny car!
keep it up you may be onto something.
DogSoldier
6 Dec 2003, 11:06am
lol, yea...I have this image of the case doors constantly popping off from all that air pressure. Geeky my man, you are a Genius.. and maybe a tad eccentric.
a2jfreak
6 Dec 2003, 11:41am
Wouldn't it yield the same effect (helping with back-pressure) to just put two 92x25mm fans one on top of the other and mount it on the SLK-900A? Basically you'd have a dual fan that's 92x50mm . . . get a couple of those 66CFM fans from SVC and rig it up.
seversphere
6 Dec 2003, 2:20pm
a2jfreak had this to say
Wouldn't it yield the same effect (helping with back-pressure) to just put two 92x25mm fans one on top of the other and mount it on the SLK-900A? Basically you'd have a dual fan that's 92x50mm . . . get a couple of those 66CFM fans from SVC and rig it up.
two axial blades on top of each other need to rotate opposite each other to have a net positive gain. So one rotates clockwise and one counterclockwise.
Geeky1: Do those blowers sound a lot quieter than the rating? My 25cfm blowers were silent compared to a TT2 fan even though they have a 55 or 57 dBA rating. I hope those have enough pressure to make it work this time around. You made a nice little setup there. If you remember I had horrible results with the nidec gamma 30. I wonder how that 80 to 92 adapter will affect your temps. Good luck!
a2jfreak
6 Dec 2003, 2:34pm
If that's the case then I guess my idea would require one fan to have inversed blades so that when it spins backwards it pushes air the same way.
seversphere had this to say
a2jfreak had this to say
Wouldn't it yield the same effect (helping with back-pressure) to just put two 92x25mm fans one on top of the other and mount it on the SLK-900A? Basically you'd have a dual fan that's 92x50mm . . . get a couple of those 66CFM fans from SVC and rig it up.
two axial blades on top of each other need to rotate opposite each other to have a net positive gain. So one rotates clockwise and one counterclockwise.
YES!
AIR COOLING POWER.
<3 Geeky.
Seversphere, they're pretty loud. Think dustbuster and you get the idea. They're not as bad as a Tornado, tho.
seversphere
7 Dec 2003, 6:03am
If they are pretty loud then they probably will work :D Do they feel the same or better than a TT2 or Tornado pressure wise? I would have saved myself a lot of trouble setting up those inadequate blowers if I had just felt them blow on my hand for a side by side comparison and realized that they weren't even close to outperforming a TT2 much less a Tornado.
a2jfreak
7 Dec 2003, 7:26am
Geeky1: Any idea what those fans would put out at a more reasonable level like say 35-40dB?
Noise Level:
Hehehe... my bad. I said they were loud. The reason they were loud is because I had them on my bench PS, which is set for 15v, not 12. :rolleyes: @12v, they're not too bad at all, actually.
A2J, I've hooked them up to 2 of the channels on one of my Nexuses, and at the minimum voltage, they're extremely quiet, and I'd guess that they're still pushing >40cfm, it certainly feels like a lot more than that, but a lot of that effect is due to the air pressure...
Pressure:
They can't even be compared to a tornado... it'd make the tornado look bad. :D
Look; these things are powerful enough that one of them is sufficient to blow an empty aluminum soda can off my desk from a distance of several feet away; you see that huge metal assembly they're attached to? That doesn't sit quite level, and the screws push it up off of whatever surface it's sitting on about 1/8", so it's got almost the right setup to function as a hovercraft. Under those conditions, that platform actually moves a bit when the blowers are first started, due to the sudden rush of air.
I'll throw together a chart once I get my room cleaned up a bit more, and you'll see just how dramatic the difference is.
a2jfreak
7 Dec 2003, 7:35am
Where's the cheapest place to get them (not necessarily those exact units, but fans of that type in general)? SVC?
I'd be surprised if SVC carried them at all. I bought mine at Fry's, believe it or not. I'm surprised they're carrying them, since 99% of the people that go there have no idea what the hell one is, let alone what to do with it (I can see it now... gee george, whatcha think it is? I dunno larry... looks like a food processor to me.... :rolleyes: ). Your best bet would be an electronics surplus place, probably.
But you'll need BIG fans to produce decent airflow. An 80mm squirrel cage fan won't be good for more than like 25cfm, if that.
BTW, these things draw 13.6w, and they have a 3 pin "motherboard style" power connector. Anyone else see a disaster waiting to happen, here?
God, I'd PAY to see some bozo hook one of these things up to a motherboard header, and turn their computer on... ;D
seversphere
7 Dec 2003, 7:41am
encouraging words Geeky1. One day I'll mod the nidec gamma 30 I have to function as case exhaust. What are the specs of that sunon? They are huge but if you beat out the tornado and others can duplicate your results then lotsa people are going to start fitting these into their case. :D
SVC is not the place to get them. LOL
allelectronics
partsexpress
or other electronics vendors you may find when you search for a specific brand or model.
2 Ball bearings, 1.13a/13.6w, 2800rpm, 40.2cfm, 56.5dba, 120x120x32mm, 250g.
I wonder if you would lose any pressure with ducting?
Like if you attatched them to the ouside of your case, and ducted it inside to the HS (directly onto it, not just blowing over it) like in my ghetto picture.
a2jfreak
7 Dec 2003, 8:19am
I think ducting might make the air a bit too turbulent, but I guess it would depend on sharp the angles are too.
well, I was thinking of more rounded tubing, with rounded curves, no angles.
if the duct were perfectly sealed to the blowers and the heatsink, you shouldn't have too much of a loss, no.
a2jfreak
7 Dec 2003, 8:47am
curves/angles. :)
croc_ had this to say
well, I was thinking of more rounded tubing, with rounded curves, no angles.
a2jfreak had this to say
curves/angles. :)
croc_ had this to say
well, I was thinking of more rounded tubing, with rounded curves, no angles.
when you said angles I was thinking sharp angles, like edges you kno? I'm tired.
TheLostSwede
7 Dec 2003, 11:23am
Never heard of a straight curve so yes, rounded curve would be right.
edcentric
7 Dec 2003, 2:30pm
Great work with the blowers. Now mount them to the side of you case, with them outside, and build a duct straight down (over?) to the heatsink. Suck fresh cool air from the room.
If you want to stack fans you need a fan that spins the oposite direction to mount between them. And super glue its blades in place. You don't want it spinning, just turning the air flow. You can make due with little fins made of plastic. Even if they are straight they help.
Isn't that what I just said? :o
croc_ & edcentric...
and I'd duct them why?
Maybe you guys have cooling problems or something... I dunno about you, but the air in all of my computer cases is at ambient temperature. Not "close" to ambient, not "near" ambient; it is the SAME temperature as the air in the room.
Therefore, ducts are useless.
Straight_Man
7 Dec 2003, 9:14pm
Geeky, under your circumstances, only reason to duct is if PSU had vents on bottom next to CPU HS and PSU ambient is high. That is why HP ducted, Power supplies were getting CPU vented heat in them and overheating.
John.
That was a bad design on HP's part, then. The PS should be able to deal with that extra heat...
regardless, I don't have that problem, so... :D
a2jfreak
7 Dec 2003, 9:25pm
my PSU (Antec TruePower 430W) has two fans. One fan blows air outside the case and one fan sucks air from inside the case. I don't know if I've ever seen a PSU that blew air into the case. That seems stupid to me.
A2J, the original ATX spec called for the fan in a PS to be an intake fan.
a2jfreak
7 Dec 2003, 9:30pm
GEEky1, that's a dumb spec. :)
I was thinking of ducting for more of space reasons, those are huge fans, not the air temp.
I wasn't passing judgement on it... :D
But that's why you'd have a ps blowing air into the case. And at the time, it actually wasn't that dumb. Air coming out of the PS on old pentium-class systems is generally no warmer than ambient. So, having the PS blow that air across the CPU made a great deal of sense at the time. Of course, if it was still that way, I'd have my 550w Antec blowing air across my dual 2500s, and they'd both be cooked. ;D
Actually croc_, they're not that big- they're 120x32mm. Besides, this thing isn't going in my case. I'll be bench testing it. That fan assembly weighs 750g or more; there is no way in HELL I'm putting that on an SLK-900A, and hanging 1250-1750g off of 6 little plastic lugs is not something I'm going to do. Especially not when the chip under the assembly is good for in excess of 2.5GHz, and if the thing falls, it'll take out my only remaining working 9700 Pro.
No, this thing is going to be tested on a nice, stable, HORIZONTAL platform. so ducting isn't an issue right now, although I may duct outside air into the blowers tonight, and if they work well, the second revision will be different. I'll keep the ducts in mind for a revised version, but right now, they aren't necessary.
Yeayh, I mean't for in the future if you were goign to use it :P It also solves the problem of weight. I wonder if a P4 HS bracket would be able to support it.
I wouldn't even trust that, personally. I might look into modifying a SP-97 to mount to the case using the old S423 P4 mounting holes, but I don't know that that is possible...
edcentric
7 Dec 2003, 10:03pm
No I wasn't worried about the air temp. I was thinking ducting for two reasons.
1. mounting, bolt them to the side of the case, the duct would be straight and trasition from the size of the blower outlets to the size of the hs.
2. Air handling for the rest of the computer. You don't want to add intake fans just to feed this thing. Let it feed the case and use exhaust fans in the case where you need flow.
Geeky1
7 Dec 2003, 11:08pm
Jesus Christ on a Raft! (tm)
I got impatient, so I did a preliminary test on my A7N8X-Deluxe, which has a 1700+ JIUHB DUT3C in it. I put a SLK-800 on it, and set the blower assembly on top.
This thing has a thermal resistance of slightly less than 0.11*C/W. :wow: :wow2:
I clocked the 1700 to just about as high as this particular A7N8X likes, which is 2200MHz (11x200). I bumped the voltage to a much higher than necessary 1.8v. At that speed/voltage, accodring to CPU Power (a CPU heat output calculator), the 1700 produces 93.8w; it's running at 32.8*C idle (can't do full load, because I don't have a HD attached to load windows). That's the actual CPU temp, too, measured by a DD5 flat thermistor that's been cut down to expose the thermistor itself, and which is taped to the side of the CPU core.
Even with the blowers at minimum speed (Vantec Nexus rheobus), it stays below 35*C. :respect:
a2jfreak
7 Dec 2003, 11:16pm
Now just funnel cold air from outside to see if you can beat 2.51GHz by using the NF7-S! :D
Well, here's the graph; the Delta EHEs are similar to the 80 & 92mm Tornados, so...
Just keep in mind that the data in this graph is not off a datasheet, but off the manufacturer's flow vs. pressure charts, so the values are very rough approximations. However, it is accurate enough for right now, so...
The esteemed Dr FrankenGeeky was seriously injured today when he ventured too close to his new Squirrel Cage Processor Cooling System.
"It has a little too much power." says Dr. FrankenGeeky. "I knew I knew I was in trouble after it consumed my digital camera, desk lamp, and Mr Igor SimGuy." (lab assistant)
Dr. FrankenGeeky is reported to be on his way to a full recovery, and is quoted as saying "It only hurts when I Overclock!"
This has been a SN New Update.
a2jfreak
8 Dec 2003, 2:23pm
Geeky needs to cut a hole in the top of his case and run tubing up into the attic and use one of these (http://www.homedepot.com/prel80/HDUS/EN_US/diy_main/pg_diy.jsp?CNTTYPE=PROD_META&CNTKEY=Products_2%2fBuilding+Supplies%2fVentilation%2fWhole+House+Fans&BV_SessionID=@@@@0833684083.1070893130@@@@&BV_EngineID=ccegadckdlkklgjcgelceffdfgidgjn.0&MID=9876) to suck the air up. Then run tubing from the AC vent directly to his HSF. That way cold air hits the HSF first and the warm air immediately gets sucked out of his case and into the attic. :)
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