Cooling

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Cooling

Postby Ricorocks » Thu Mar 30, 2017 2:28 am

Just arrived Dell T3500 Precision server. THANKS Foldy!!!!!!

Upcoming modification, 550 or 600W gold PSU, Two GTX 1070's

The machine has 0 case fans.

Rear can accommodate 2 smaller fans, front 1 smaller fan. It's final placement, never goes over 80F, mostly 75 - 78F.

I was thinking "positive psi" more CFM in than out. What spread or delta CFM's, btwn. IN & OUT is reasonable

Say 100 cfm in so out CFM/s should be 90, 80, 70...10? I'll be limited by say noise, so fans should be, less than 60 db

So maybe something like this in https://www.newegg.com/Product/Product. ... -_-Product

The rear exhaust has room for two fans, if two fans used, would that be cumulative 1 40cfm fan + 1 40cfm an = 80 cfm total exhaust. Seems logical. Also using two fans (meeting the spread btwn. in & out, seems better than one rear fan making 80cfm.

Or should I go a different approach to remove heat???

Thanks
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Re: Cooling

Postby ComputerGenie » Thu Mar 30, 2017 3:32 am

If it's the case I think it is, my suggestion would involve some tin snips and some 120mm fans.
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Re: Cooling

Postby FAMAS » Thu Mar 30, 2017 5:02 am

Ricorocks wrote:Just arrived Dell T3500 Precision server. THANKS Foldy!!!!!!

Upcoming modification, 550 or 600W gold PSU, Two GTX 1070's

The machine has 0 case fans.

Rear can accommodate 2 smaller fans, front 1 smaller fan. It's final placement, never goes over 80F, mostly 75 - 78F.

I was thinking "positive psi" more CFM in than out. What spread or delta CFM's, btwn. IN & OUT is reasonable

Say 100 cfm in so out CFM/s should be 90, 80, 70...10? I'll be limited by say noise, so fans should be, less than 60 db

So maybe something like this in https://www.newegg.com/Product/Product. ... -_-Product

The rear exhaust has room for two fans, if two fans used, would that be cumulative 1 40cfm fan + 1 40cfm an = 80 cfm total exhaust. Seems logical. Also using two fans (meeting the spread btwn. in & out, seems better than one rear fan making 80cfm.

Or should I go a different approach to remove heat???

Thanks

i would suggest to not use fan, instead to use phase change coolers as in portable air conditioners.
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Re: Cooling

Postby Ricorocks » Thu Mar 30, 2017 9:00 pm

I don't think OSA, or the computers intake air is at issue, as intake air is never above 80F. Removing the heat inside the case, is the question.

Positive psi More CFM's "IN" than "OUT" Whats the sweet spot, for CFMs

Negative psi More CFM's "OUT" than "IN" Would also have a sweet spot for the differential btwn in & out CFM's <Suddenly I have the craving for "In & Out burger">

"i would suggest to not use fan, instead to use phase change coolers as in portable air conditioners." This strategy relies on thermodynamics (heat always flows to cold), or natural cooling, fans assist. So cooling the intake air is rather expensive.

Also tin snips to allow for larger fans, is not an option, a new case, would be easier, but much more expensive than Fans.
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Re: Cooling

Postby jrweiss » Thu Mar 30, 2017 11:02 pm

Positive pressure will significantly reduce the dust accumulation in the box, since all intake air will be via the [filtered] intake fan. With negative pressure, dust will be sucked in via ALL crevices...

Don't forget to include the PSU fan in your calculation, as well as any contribution by GPU exhaust through the backplane. You MAY find that you don't need additional exhaust fans, depending on the setup.

What is the total TDP of the CPU + GPUs? How much air do the GPUs exhaust through the backplane? Is the PSU isolated, or in the main case compartment? Is its fan thermally controlled, or constantly on?

It's hard to recommend a setup without knowing the exact layout of the system...

With a lower-power unit, a single, efficient (e.g., Noctua NF-S12A, 63 cfm @17.8 dB(A)) 120mm intake fan may be adequate (though I use dual 120s with PWM control). However, you will likely need more than that with the dual GPU setup. If you already have exhaust via the PSU and GPUs, you may have to use the rear fans as intake fans. Use slotted backplane covers to direct airflow as needed (e.g., near the GPU backplanes). Type and orientation of the CPU cooler are factors as well.
i4770K/AMD RX460 (CPU6+GPU), i7-3770S/AMD7750 (CPU6+GPU), Win7-64 Pro
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Re: Cooling

Postby foldy » Fri Mar 31, 2017 9:26 am

I found the air flow in my case was the best with equal count of blow in and blow out fans.
All fans in the lower half of the case blow in from front, bottom and side.
All fans in the upper half of the case blow out from side, back and top.

My power supply is independent from case air flow because it blows in from bottom and out again at back.

All my fans are silent so I needed more of them.
My GPUs run cooler with closed case than with open case so that's a good cooling.
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Re: Cooling

Postby Ricorocks » Fri Mar 31, 2017 1:44 pm

Messrs jrweiss, foldy: Great posts Thank You!
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