BFL Single air flow? | Bitcointalksearch.org

Gator-hex

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Activity: 490

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Fans should always blow down into the heatsink, not only do they run cooler this way around they also keep the other components cool on the board cool too. This is especially important for VRMs/power modules.

Bigger fans = less noise. The design of the blades doesn't matter as much as a lower rotational speed for getting noise down. Getting extra number of blades in the fan improves CFM (airflow) for the same rotation speed.

If people want low noise miners I recommend the Bitfury chip stuff as they don't get very hot.
My Hex16B are running 92mm Arctic F9 (9 blade) 1800RPM 0.4 SONE 43CFM fans and they're quiet enough to be in the same room I watch TV.

foobar31

newbie

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Just my 2 cents if people are still using this device and trying to mod it.

I tried to replace the default fans by others (which were not good enough in terms of pressure...) but it makes me discover something after re-mounting the default ones...
For me it appears that the flow direction has a high importance, you'll get better result if it goes from right to left when looking at the SC from the rear (where the power/usb connectors are).

With the default fans and an open box : 64°C +/- 1°C
In the wrong direction : 70°C +/- 2°C

Cheers

ewibit

legendary

Activity: 2955

Merit: 1049

I get always

Code:

hex2bin scan failed

with my LS and cgminer 3.8.x
is this perhaps an issue with temperature?
I have to unplug the device and in a few minutes replug and with luck it is working again (a little time...)
TIA

rupy

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Activity: 725

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Ok, last update I hope (is anyone even reading this crap?) so I now choke the two top fans (with resistors to reduce noise) and keep the side fan full speed. It seems the side fan position is the secret sauce to cooling these, it induces an airflow of fresh air between the heatsinks through the slim gap between the sinks and the top fans. ~~Getting taller risers or cutting the sinks a little (need to keep pressure on the whole side of the PCB to cool other stuff) would maybe perform miracles.~~ That did NOT work, hotter and more turbulent... Anyhow even more silent now and only 1 degree warmer!

rupy

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Received my RMA Single, something has changed, lots of components are different and it runs MUCH cooler, 62C with thermal pads!! Only 55GH but definetly an improvement. Running the BFL PSU for 4 days until I move the Single to my house, boy that PSU is some nasty peice of hardware, hope it will last 4 days, doubt it.

Edit: cracked the PSU open after 10 minutes of soul scorching noise. Cooling it with another silent fan instead.

rupy

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Ok, an update, you need to replace the thermal pad with thermal grease... the chips are completely leveled, at least on my machine, 10 degrees difference!!!

Then for silent cooling it's this side that needs it. I chooked the sideways fan so it doesn't blow on the top fans, you could try with a smaller fan that doesn't reach over the top too. Edit: definetly go for 92mm fan for the side fan.

The little black thing on the right ledge is a spider that likes the miner. It lives next to it!

It's not sleep quiet, but it's almost work quiet, not in the same room, but at least it keeps the neighbors from complaining.

Too bad BFL "ran out" of heatpipes!

EDIT: The position of the side fan is dangereous, I suspect it blows directly at the temperature sensor therefore tricking the single it is cooler than it actually is. I burned 1 chip for good and 3 more that needs cooling before booting to work! Damn BFL for not delivering heatpipes so we could cool these quietly!!!

The chips are all back, seems the firmware is shutting things down if they get too hot; even across reboots!?

rupy

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I used BTC, but I used mined BTC so "no problem". I bought FPGA, so I'm still ROI all-in-all, even after ordering BFL. Now I'm just trying to cool these silently so they can heat my house, going noctua today, fingers crossed!

Edit: Noctua 92mm on top blowing down and usb fan pushing sideways (only required because aluminium heatsinks are directional), 79 degrees, 57GH. And silent enough to not go insane while sitting next to it.

Damn BFL for replacing the heatpipes with aluminium heatsinks though (and not even replying on queries about buying heatpipes), could have made it completely silent with those!

I'm going to start project "turn heatsinks 90 degrees". Need to make new screwholes...

Easy2Mine

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Activity: 854

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einc.io

Quote from: rupy on November 11, 2013, 05:00:53 PM

Does anyone know which mount the heatsinks use? New singles get shipped with aluminium heatsinks instead of heatpipes which are harder to cool silently. Boy, do I regret ordering these!

You are not the only one regretting ordering those junkyard stuff.
I hope you use dollar to order those bicthes.
If you do, you can still earn your money back.
I and everyone else who use BTC to order won't see that amount in BTC back.

Quix

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Activity: 174

Merit: 100

Quote from: rupy on November 11, 2013, 05:00:53 PM

Does anyone know which mount the heatsinks use? New singles get shipped with aluminium heatsinks instead of heatpipes which are harder to cool silently. Boy, do I regret ordering these!

Cheap aluminum heatsinks? That's rough, especially for the price. The first thing I thought when I saw these things is that they could use better heatsinks and the intake fans mounted to the top of the case blowing down (they'd need less fans). It looks like BFL really doesn't know what they're doing.

rupy

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Activity: 725

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Does anyone know which mount the heatsinks use? New singles get shipped with aluminium heatsinks instead of heatpipes which are harder to cool silently. Boy, do I regret ordering these!

rupy

hero member

Activity: 725

Merit: 503

Just one big 20cm fan for each 2x BFL naked front to front. Waiting for my 2nd.

Basically the first thing you need to do is throw away everything except the baseplate, PCB and heatpipes/sinks.

The case, fans and PSU are COMPLETE GARBAGE!

Temp: 64C
Engines: Only 201/256, see https://bitcointalksearch.org/topic/post-your-bfl-sc-60-procengine-details-here-320687!
Noise: You can sleep next to it if you are ok with electronics that whine. Air noise = same as ambient.

Easy2Mine

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Activity: 854

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einc.io

The form of the tunnel is very important.
Look at the last picture, the drawing I made in blue is from the side angle of the metal sheet.
The air has to be squeeze though the fins of the heatsink.
The plastic foam I put on top of the metal sheet has 2 functions.
1. Absorb the vibration of the air going through the fins of the heatsink.
2. Make sure air is guided through the tunnel, air is forced to take the easiest way through the tunnel.
The cover of the single has to stay on, or it won't cool the heatsinks on the bottom of the pcb effectly.
If those heatsinks on the bottom of the pcb is not cooled enough, your singles won't last longer than half a year and your hashrate is dropping.

johnyj

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Beyond Imagination

Quote from: Easy2Mine on October 27, 2013, 06:38:22 AM

The form of your tunnel is very important. A venturi effect work the best with case on.
You probably has the case off.
Really dangerous for overheating the other components on the pcb if you don't have a fan
Blowing at them.

The case was all on, and that made it even more difficult to adjust since I had to take down the case every time I modify the tunnel. Since I replace the 120MM fan with GT1850 (highest CFM/noise ratio fan out there), it should give enough pressure, but it did not work well

I noticed that you filled the upper part with sponges, maybe that helped

Easy2Mine

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einc.io

The form of your tunnel is very important. A venturi effect work the best with case on.
You probably has the case off.
Really dangerous for overheating the other components on the pcb if you don't have a fan
Blowing at them.

johnyj

legendary

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Beyond Imagination

I did a similar mod with removing the 92mm fans and adding a tunnel, the temp went up by 10 degree, so I have to put them back Undecided

Easy2Mine

hero member

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einc.io

I removed both the 92 mm heatsink fans.
I cut a big hole into the intake and exhaust plates. (See photo, the single at top right)
I cut a metal sheet from a cookie can and bend it into the right form for the venturi effect.
I put plastic foam to reduce noise.

I put the cover on.
Temperature is almost 10 degree Celsius lower than original singles.
Only if you bend the metal sheets in the right form. You can bend the metal sheets in different form to see that it has a big impact on noise and temperature.
After a few days I decide to change the fans speed by putting an electrical conductor to reduced the noise even further.
The white intake fan don't work with an electrical conductor, you have to change it with your own 120 mm fans.
How ever the black exhaust fan that come with the single don't have problems with an electrical conductor.

Almost no noise and still 2 degree lower than the original temperature.
And it is recommended to put the cover back on unless your setup also can cool the other components.
There are so many design flaws with the BFL singles that it can be easily overheated and catch fire without the cover on.

1l1l11ll1l

legendary

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Quote from: 2GOOD on October 23, 2013, 04:43:09 PM

Here is my mod. That was the first thing to do back in August when I get thoose jet engines Shocked

The tunel is back on without 92mm fan and the fan grills. With the original cooling the device was at 68C.
Now the device is with NB PWM 2000rpm model runing at 60-62C - 31.5 GH/s

best
2GOOD

Nice!

1l1l11ll1l

legendary

Activity: 1274

Merit: 1000

Quote from: dogie on September 02, 2013, 07:55:00 PM

Cooling is much better when blowing through rather than sucking through a heatsink. As others have said, it takes a worse path when sucking through. This is because the pressure profile on either side of the fan isn't the same, its much stronger and compact on the blowing side.

Additionally, the rest of the PCB and components need airflow that a sucking arrangement wouldn't provide.

The singles come from the bfl factory both fans sucking up. I switched to blowing down, buttoned it back up and the temp increased. Don't know why but they got it right with the sucking.

2GOOD

hero member

Activity: 547

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First bits: 12good

Here is my mod. That was the first thing to do back in August when I get thoose jet engines Shocked

The tunel is back on without 92mm fan and the fan grills. With the original cooling the device was at 68C.
Now the device is with NB PWM 2000rpm model runing at 60-62C - 31.5 GH/s

best
2GOOD

Sc@rF@c3

newbie

Activity: 56

Merit: 0

Quote from: r3animation on October 01, 2013, 07:45:57 AM

I replaced the 2 x 92mm fans on the heatsinks to 2 x 120mm Gentle Typhoon AP-15s. Runs naked on my desk with no sound at all @ 60C.

I'm very interested in quieter alternatives, had the noise patrol come around last Saturday, the miners were keeping the neighbors awake, well done BFL.
Would also like to see a photo of this setup, how did you install the 120's, I only see space for 92's.
Wondering if quieter 92 fans will do the same job as your 120's.

Look forward to seeing the setup

Cheers

Kaega

full member

Activity: 158

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Quote from: r3animation on October 01, 2013, 07:45:57 AM

I replaced the 2 x 92mm fans on the heatsinks to 2 x 120mm Gentle Typhoon AP-15s. Runs naked on my desk with no sound at all @ 60C.

You mind posting a picture of this setup? I am assuming that you are not utilizing the 120s from the ends. How did they mount?

Disclaimer: I just got my hair dryers and am looking to replace the noisy fans.

bobitza

sr. member

Activity: 560

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Quote from: r3animation on October 01, 2013, 07:45:57 AM

I replaced the 2 x 92mm fans on the heatsinks to 2 x 120mm Gentle Typhoon AP-15s. Runs naked on my desk with no sound at all @ 60C.

So you just put the 2 x 120mm fans on top of the heatsinks blowing down ... do they fit? I mean how did you hold them in place?

Also, did you connect them to the original heatsinks connectors on the board or hooked them to the connectors for the intake/exhaust fans?

Do you think 2 of these will do the job? Corsair SP120: http://www.directcanada.com/products/?sku=11180AC0334&vpn=CO-9050007-WW&manufacture=CORSAIR

eestimees

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Quote from: r3animation on October 01, 2013, 08:13:11 AM

Quote from: eestimees on October 01, 2013, 08:07:49 AM

Quote from: eestimees on October 01, 2013, 12:50:12 AM

Quote from: johnyj on September 30, 2013, 05:32:29 PM

Replace the 120MM fan with GT1850

not very widely common in EU Sad

hm.. that is not very high airflow (cfm) is that really enough? I would have thought more is needed..

Hmm I think the AP15 moves around 58 CFM. What kind of airflow are you looking at?

sorry, I was thinking of avalon fans while writing this

anyway I found an interesting fan:

http://www.frozencpu.com/products/11637/fan-745/Aerocool_Shark_Black_Edition_120mm_x_25mm_High_Air_Pressure_Fan.html?tl=g36c15s60

quiet and powerful...

r3animation

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Quote from: eestimees on October 01, 2013, 08:07:49 AM

Quote from: eestimees on October 01, 2013, 12:50:12 AM

Quote from: johnyj on September 30, 2013, 05:32:29 PM

Replace the 120MM fan with GT1850

not very widely common in EU Sad

hm.. that is not very high airflow (cfm) is that really enough? I would have thought more is needed..

Hmm I think the AP15 moves around 58 CFM. What kind of airflow are you looking at?

eestimees

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Quote from: eestimees on October 01, 2013, 12:50:12 AM

Quote from: johnyj on September 30, 2013, 05:32:29 PM

Replace the 120MM fan with GT1850

not very widely common in EU Sad

hm.. that is not very high airflow (cfm) is that really enough? I would have thought more is needed..

r3animation

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Quote from: eestimees on October 01, 2013, 08:01:30 AM

Quote from: r3animation on October 01, 2013, 07:45:57 AM

I replaced the 2 x 92mm fans on the heatsinks to 2 x 120mm Gentle Typhoon AP-15s. Runs naked on my desk with no sound at all @ 60C.

well.. I do not want to strip single.. as components on and under the pcb are less cooled then..

Well I'm pushing air through the heatsinks and it seems ok so far. No crashes or reboots since I got it last week.

eestimees

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Quote from: r3animation on October 01, 2013, 07:45:57 AM

I replaced the 2 x 92mm fans on the heatsinks to 2 x 120mm Gentle Typhoon AP-15s. Runs naked on my desk with no sound at all @ 60C.

well.. I do not want to strip single.. as components on and under the pcb are less cooled then..

r3animation

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Activity: 756

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I replaced the 2 x 92mm fans on the heatsinks to 2 x 120mm Gentle Typhoon AP-15s. Runs naked on my desk with no sound at all @ 60C.

eestimees

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Quote from: johnyj on September 30, 2013, 05:32:29 PM

Replace the 120MM fan with GT1850

not very widely common in EU Sad

johnyj

legendary

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Beyond Imagination

Replace the 120MM fan with GT1850

joeventura

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So what you are saying is BFL designed it wrong?

I find that hard to believe.

Tongue

eestimees

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Quote from: phr0stbyt3 on September 30, 2013, 02:28:34 PM

What about venting the top of the case and making both end fans pull air in?

I though that too but did not want to cut or drill the original case of single... But if you do that some air shrouds are reccomended to push amd pull the air the right way and quietly.

eestimees

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Quote from: bobitza on September 30, 2013, 11:55:17 AM

Hi eestimees

From the picture, the "mod" looks to be made from metal. I don't have a metal sheet nor the tools to bend one if I had it in the first place, but I'm interested in modding the Single.

Do you (guys) think that a hard cardboard could do the trick? Is it safe to use cardboard in the first place? aka it doesn't catch fire from the heat.

Yes, it has been cut out from old miditower case. The heat on top is not so high, but i would not reccon paper or cardboard anyway.. For me it is too much risk.

phr0stbyt3

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What about venting the top of the case and making both end fans pull air in?

bobitza

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Hi eestimees

From the picture, the "mod" looks to be made from metal. I don't have a metal sheet nor the tools to bend one if I had it in the first place, but I'm interested in modding the Single.

Do you (guys) think that a hard cardboard could do the trick? Is it safe to use cardboard in the first place? aka it doesn't catch fire from the heat.

mtbitcoin

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Etherscan.io

Quote from: JimiQ84 on September 30, 2013, 02:36:44 AM

Quote from: dogie on September 30, 2013, 02:23:20 AM

0_O That is telling you nothing has changed.

power consumption is lower ;-)

Lesser noise :-)

JimiQ84

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Quote from: dogie on September 30, 2013, 02:23:20 AM

0_O That is telling you nothing has changed.

power consumption is lower ;-)

dogie

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Quote from: eestimees on September 30, 2013, 12:24:56 AM

here you go

both on the same pic:

close-up with same temp scale:

modded:

original:

so, I'm happy and end of story. going to modify second one too.

0_O That is telling you nothing has changed.

eestimees

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here you go

both on the same pic:

close-up with same temp scale:

modded:

original:

so, I'm happy and end of story. going to modify second one too.

dogie

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Quote from: eestimees on September 09, 2013, 05:54:47 AM

Quote from: dogie on September 09, 2013, 05:51:50 AM

Non steady state conditions tell you nothing about the cooling capacity of the system, too many things going on.

And by that you mean? Sorry but english is not my 1st language.

Steady state typically means when everything in is the same as everything going out. In this case, when the heatsink gets to a constant, stable temperature, effective steady state is reached.

ewibit

legendary

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is it possible that my BFL LS has this problems because airflow?

Code:

2013.09.09 [17:11]  BitFORCE (ttyUSB0) ERROR: Unexpected response without command: BitForce SHA256 SC 1.0 
2013.09.09 [17:11]  BitFORCE (ttyUSB0) ERROR: Command timed out. Retries: 0 
2013.09.09 [17:11]  Probe of port /dev/ttyUSB0 failed: timeout 
2013.09.09 [17:13]  BitFORCE (ttyUSB0) ERROR: Unexpected response to work results poll command: BitForce SHA256 SC 1.0 
2013.09.09 [17:13]  BitFORCE (ttyUSB0) ERROR: Unexpected response to temperature check command: INPROCESS:1 
2013.09.09 [17:13]  BitFORCE (ttyUSB0) ERROR: Unexpected response to temperature check command: COUNT:16 
2013.09.09 [17:13]  BitFORCE (ttyUSB0) ERROR: Unexpected response to temperature check command: 283DF32FA7E2E8C4E19BFDFC0E59355142FF2A3B01C658891AD9D0743EEA14A2,B7C23A1A522DE58E1931679C,5,1,6BC1B0FE 
2013.09.09 [17:13]  BitFORCE (ttyUSB0) ERROR: Unexpected response to work queue flush command: 283DF32FA7E2E8C4E19BFDFC0E59355142FF2A3B01C658891AD9D0743EEA14A2,B7C23A1A522DE5981931679C,2,3,1B251CAF,28F291D5,B0A3BE86 
2013.09.09 [17:13]  BitFORCE (ttyUSB0) ERROR: Unexpected response to queue job pack command: 283DF32FA7E2E8C4E19BFDFC0E59355142FF2A3B01C658891AD9D0743EEA14A2,B7C23A1A522DE59D1931679C,0,2,66804588,851B4256 
2013.09.09 [17:13]  BitFORCE (ttyUSB0) ERROR: Unexpected response to queue job pack command: 283DF32FA7E2E8C4E19BFDFC0E59355142FF2A3B01C658891AD9D0743EEA14A2,B7C23A1A522DE59C1931679C,7,0 
2013.09.09 [17:13]  BitFORCE (ttyUSB0) ERROR: Unexpected response to temperature check command: 283DF32FA7E2E8C4E19BFDFC0E59355142FF2A3B01C658891AD9D0743EEA14A2,B7C23A1A522DE5A21931679C,4,0 
2013.09.09 [17:13]  BitFORCE (ttyUSB0) ERROR: Unexpected response to temperature check command: 283DF32FA7E2E8C4E19BFDFC0E59355142FF2A3B01C658891AD9D0743EEA14A2,B7C23A1A522DE5AC1931679C,3,1,E9C671B0 
2013.09.09 [17:13]  BitFORCE (ttyUSB0) ERROR: Command timed out. Retries: 0 
2013.09.09 [17:13]  Probe of port /dev/ttyUSB0 failed: timeout

it stops after ~1-2 hours and is not starting automatically again (exept for starting BitMinter client manually new)
(I have removed the inflow plate because with this it is much louder and stops quickier)
TIA

JimiQ84

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Quote from: Bicknellski on September 09, 2013, 06:13:37 AM

Let us keep it simple. Does the unit have temperature sensors? Are they showing better cooling? Are you getting better hashrate?

If you are good enough.

I'd say temperature is the same and power usage is some 2-4W lower

Bicknellski

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Let us keep it simple. Does the unit have temperature sensors? Are they showing better cooling? Are you getting better hashrate?

If you are good enough.

eestimees

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Quote from: dogie on September 09, 2013, 05:51:50 AM

Non steady state conditions tell you nothing about the cooling capacity of the system, too many things going on.

And by that you mean? Sorry but english is not my 1st language.

dogie

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Quote from: eestimees on September 09, 2013, 05:37:22 AM

Quote from: dogie on September 09, 2013, 05:21:51 AM

Quote from: eestimees on September 09, 2013, 03:56:38 AM

we'll see when i get the thermal cam in my hand, we'll see... I only need to figure out how to take pictures so that metal case would not block my "heat view".. I mean, I can't take pics when cover is taken off.. then the air will not tunnel through.. and taking pics with cover on I cant see single component heat.. I can only see heat spots on case.. maybe that is enough though...

Thermal cam won't particularly help. Just look at core temps at a fixed ambient and fan rpm.

as I think I mentioned before, "my design" appear to push out less air, and hashing temp is the same (although reaching same temp takes more time) = less rpm needed to cool to same temp, but that's not all, shutting down miner and starting again show that modified single has cooler starting temp = it must be more efficient as air goes thru single and does not hassel around-up-n-down (also less noisy), now i order to see if everything is cooled and compare original design with my design I was thinkig of takeking thermal images where both are in front of me on the table, and outside (to get bigger contrast of cold/warm).

Non steady state conditions tell you nothing about the cooling capacity of the system, too many things going on.

eestimees

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Quote from: dogie on September 09, 2013, 05:21:51 AM

Quote from: eestimees on September 09, 2013, 03:56:38 AM

we'll see when i get the thermal cam in my hand, we'll see... I only need to figure out how to take pictures so that metal case would not block my "heat view".. I mean, I can't take pics when cover is taken off.. then the air will not tunnel through.. and taking pics with cover on I cant see single component heat.. I can only see heat spots on case.. maybe that is enough though...

Thermal cam won't particularly help. Just look at core temps at a fixed ambient and fan rpm.

as I think I mentioned before, "my design" appear to push out less air, and hashing temp is the same (although reaching same temp takes more time) = less rpm needed to cool to same temp, but that's not all, shutting down miner and starting again show that modified single has cooler starting temp = it must be more efficient as air goes thru single and does not hassel around-up-n-down (also less noisy), now i order to see if everything is cooled and compare original design with my design I was thinkig of takeking thermal images where both are in front of me on the table, and outside (to get bigger contrast of cold/warm).

dogie

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Quote from: eestimees on September 09, 2013, 03:56:38 AM

we'll see when i get the thermal cam in my hand, we'll see... I only need to figure out how to take pictures so that metal case would not block my "heat view".. I mean, I can't take pics when cover is taken off.. then the air will not tunnel through.. and taking pics with cover on I cant see single component heat.. I can only see heat spots on case.. maybe that is enough though...

Thermal cam won't particularly help. Just look at core temps at a fixed ambient and fan rpm.

eestimees

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we'll see when i get the thermal cam in my hand, we'll see... I only need to figure out how to take pictures so that metal case would not block my "heat view".. I mean, I can't take pics when cover is taken off.. then the air will not tunnel through.. and taking pics with cover on I cant see single component heat.. I can only see heat spots on case.. maybe that is enough though...

Bicknellski

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Quote from: dogie on September 09, 2013, 03:10:00 AM

Quote from: Bicknellski on September 09, 2013, 02:17:46 AM

If it works great job.

Guessing the venturi effect is helping move that heat away nicely.

*Around the heatsink through the massive 0 resistance gap, yup. No way that is cooling better than before.

Evidence to support your theory it doesn't work, possibly some models or math to prove that?

Basically calling the guy a liar, I am pretty much inclined to give him the benefit of the doubt at this point given the inelegant solution that was devised by BFL in the first place. Time for some numbers and proof cause dogie is calling you out eestimees.

dogie

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Quote from: Bicknellski on September 09, 2013, 02:17:46 AM

If it works great job.

Guessing the venturi effect is helping move that heat away nicely.

*Around the heatsink through the massive 0 resistance gap, yup. No way that is cooling better than before.

Bicknellski

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If it works great job.

Guessing the venturi effect is helping move that heat away nicely.

eestimees

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here it is

and still i'm pretty sure it is not only quieter but efficient too. still thermal imaging to be done to measure temp under the board and so.

dogie

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Quote from: eestimees on September 08, 2013, 08:03:17 AM

Got my singles, today i moded one as i described, and it feels to me that it is more efficient. They are both side by side, hashing 61-63C. When i stop miner and start again, the modded single temp is much lower than original cooling setup. Within few minutes, they both are at the same temp again, but it feels like modded one's airflow is ligther = fans rotating slower.

Tomorrow i upload some pics of how i did it. I will try to get something to measure airflow and friend said he can borrow thermal cam to take pics.

tldr: You won't be able to get anything that measures airflow to any meaningful precision, unless you have a venturi arrangement.

eestimees

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Got my singles, today i moded one as i described, and it feels to me that it is more efficient. They are both side by side, hashing 61-63C. When i stop miner and start again, the modded single temp is much lower than original cooling setup. Within few minutes, they both are at the same temp again, but it feels like modded one's airflow is ligther = fans rotating slower.

Tomorrow i upload some pics of how i did it. I will try to get something to measure airflow and friend said he can borrow thermal cam to take pics.

dogie

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Cooling is much better when blowing through rather than sucking through a heatsink. As others have said, it takes a worse path when sucking through. This is because the pressure profile on either side of the fan isn't the same, its much stronger and compact on the blowing side.

Additionally, the rest of the PCB and components need airflow that a sucking arrangement wouldn't provide.

chanberg

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I have 4 Jalapenos, and I arrange them in a stack of 2 open case (so two stacks, one on top of each other). If I leave it the way it is, it runs about 40C, if i put two fans next to them in a push pull manner, they drop 6C to about 34... So the two fans do make a difference believe it or not.. Also the push pull config fans are pointed in the direction of the heatsink grooves..

ASIC-K

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Hell?

the small fans blow UP not down.

i have a single, and this is how it works.

crazyates

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Quote from: eestimees on September 02, 2013, 06:41:45 AM

Problem: The 2 smaller fans don't blow down. They blow up, IIRC. People who have been running them out of their case have been reversing the direction so the fans blow down.

I feel like it's an interesting idea, but IDK how well it will work. The heatsink has a significant gap between the actual chip and the heatsink itself, so I don't feel it would be completely effective.

I've actually heard that the noise can be cut down significantly by running it outside of it's case, and with 2 quieter fans replacing the heatsink fans, but blowing down.

Still, you've got to remember: dissipating 200+Watts of heat is not an easy thing to do, although I do feel that 4 fans is a big overkill.

k9quaint

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Quote from: bcp19 on September 02, 2013, 08:32:31 AM

Quote from: rupy on September 02, 2013, 07:29:39 AM

I think the best solution for sound here is remove the case and all fans, then place 2 singles next to eachother and put one big fan on top that covers all 4 heatsinks. Also why are all top mounted fans blowing DOWN?? Heat naturally goes UP!!

The heat will go naturally up... the fins of the heat sink. The narrowness of the fins combined with their height gives a lot of surface area for the radiation of heat off of the fins. Many Jalapeno owners have already stated that the stock position of the fan (blowing up, thereby pulling air through the fins) results in the system running several degrees hotter than if the fan is blowing down into the fins. It is much easier to get a uniform airlfow by pushing air than by pulling it.

When pulling air through a fan, it will take the path of least resistance into the fan. Thus it will not flow over the entire surface of the heat sink fins, but instead flow in along the top. Using the fan to push, thereby forcing air all the way down into every crevice of the heat sink creates airflow along the entire surface area of the heat sink which increases the amount of heat that can be transferred away.

bcp19

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Quote from: rupy on September 02, 2013, 07:29:39 AM

I think the best solution for sound here is remove the case and all fans, then place 2 singles next to eachother and put one big fan on top that covers all 4 heatsinks. Also why are all top mounted fans blowing DOWN?? Heat naturally goes UP!!

The heat will go naturally up... the fins of the heat sink. The narrowness of the fins combined with their height gives a lot of surface area for the radiation of heat off of the fins. Many Jalapeno owners have already stated that the stock position of the fan (blowing up, thereby pulling air through the fins) results in the system running several degrees hotter than if the fan is blowing down into the fins. It is much easier to get a uniform airlfow by pushing air than by pulling it.

eestimees

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Quote from: rupy on September 02, 2013, 07:29:39 AM

I think the best solution for sound here is remove the case and all fans, then place 2 singles next to eachother and put one big fan on top that covers all 4 heatsinks. Also why are all top mounted fans blowing DOWN?? Heat naturally goes UP!!

you are joking, right? to cool them with one fan, it has to be a powerful and I doubt that it would be a quiet one, as the needed airflow (CPM) is a lot...

my main concern with this topic was, IMHO those fans inside case are working against each-other, I mean on the picture the left fan do not get much free air to blow down as the fan on the right has taken most of the incoming cool air away..

rupy

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I think the best solution for sound here is remove the case and all fans, then place 2 singles next to eachother and put one big fan on top that covers all 4 heatsinks. Also why are all top mounted fans blowing DOWN?? Heat naturally goes UP!!

eestimees

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ok, thanks!

dogie

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Quote from: eestimees on September 02, 2013, 07:13:21 AM

yes but when one has that blue airflow bracket, then the flow is forced to the sink and there would be a single continuous and effective air flow through the single (of-course case close not in open air) ...? that should be much quieter also.. in the original design air has multiple obstacles/high and low pressure points and different direction airflows collide.. all that is noisy and ineffective IMHO.

It would be inefficient, but not noisy. Get two case fans and hold them far apart and together, doesn't make much difference.

I didn't realise you had that as a bracket, but the design still doesn't work. You can't make an air tight seal around the heatsink, and so the air will still rather go around than through. There is a lot of flow resistance associated with high surface area.

eestimees

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yes but when one has that blue airflow bracket, then the flow is forced to the sink and there would be a single continuous and effective air flow through the single (of-course case close not in open air) ...? that should be much quieter also.. in the original design air has multiple obstacles/high and low pressure points and different direction airflows collide.. all that is noisy and ineffective IMHO.

dogie

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Yes they are. Without the small ones blowing directly through the fins, the majority of the air would just find the path of least resistance, which is around the sides of the heatsinks.

Arguably in an open case the two larger fans aren't required, but we don't know for sure the cooling requirements on the non-chip components.

eestimees

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Hi,

I've been looking at those single pictures (don't have one my own) and read about those whinigs about noise level... I was wondering are those two small fan's really nessesary ? I've made a drawing as I _think_ air flow goes.. and would be much quieter (if you replace those side plates):

I'm I wrong?

Topic: BFL Single air flow? (Read 6924 times)