Topic: Push pull or both for air vent for mining room (Read 544 times)

If you're venting in quite a cold environment I'd suggest venting out rather than in. If you pull air in you could run into trouble if your rig goes offline, at which point condensation could form on your equipment (at least i think). 

I suggest you just focus on the exhaust fans and make sure your pulling enougb of the hot air out.
Intake fans from my experience is not a big concern. Well depending how big of a room or facility your talking about. But as long as you can crack a window or a vent maybe for fresh air. The exhaust fans will do the job of exhausting the heat out of the room, while pulling the fresh air into the room.

Hmmm i have a similar amount of gpu running in my facility. In one of the hottest country in asia also.
My exhaust fans doing wonders for me at the moment. But i do have big louvers for air intake. But no intake fans. Only exhaust fans to keep the hot air out while pulling fresh air in.  
Also 50C is hot? For a gpu farm? To the point paint is melting off the walls? Thats crazy. At night my coolest temp for my cards are just under 50C. Hottest is just below 70C in thr afternoon.

Maybe im running my gpu side of the facility too hot.

*edit nevermind. Your talking about ambient room temp.  , does sound like a sauna in there.

Unless you have a LOT of flow restriction, pick one or the other - doing both push AND pull doesn't help airflow significantly otherwise and DOES waste power.

Work WITH natural airflow can help noticeably too.

I have two fans in a 4" duct. And two big portable room fans. I dont care about the temperature in the room. I care about the temperature of the gpus. I tired several solutions the best being: i supply fresh air with both duct fans right to the big room fans. They blow the hot air away from the gpus with cold outside air. I have made some holes in the door and vent holes in the window to release the pressure added by the duct fans and make airflow easier.

That is incorrect. The same somewhere that can suck air in can also blow it out. It's all about temperature difference and volume.
Push-pull is always better but if you have to choose one try to complement natural air flow. If you have a natural breeze blowing
in the window you don't need an intake fan there, use an exhaust fan instead far from the intake window (second window, doorway).

I have a 'mining room' where I keep my rigs, at one end are 4 open holes with exterior cowl covers and filters to stop debris, they are at ground level to allow cooler air in ... and at the other end I have a large fan pulling the heat out. Works well for me. The intake end is around 7-8 degrees C cooler than the extractor end.

You always want to pull air out, that is an "exhaust fan" and will always make for better circulation. When the fan is pulling air out of a space, it is creating a vacuum and will allow air to be sucked in (from somewhere, more later). Pushing air in will only pressurize the space not allowing the hot air to evacuate the space as quickly thus slowly heating up the space that you are trying to cool.

You also don’t want the intake and exhaust right next to each other as it will just suck the hot air right back in and pull the cold air right back out. If the intake and exhaust are going to be in the same window, install some type of divider between the 2 that extends at least a foot.  In a perfect world you would want 1 intake fan and 1 exhaust fan in 2 different areas of the room. But if you only have 1 fan then blow the air out and open a window that is close for fresh air. Even just a crack will help. If you don’t you will be sucking air from the main house, even with the door closed (unless it’s a sealed exterior door), and in the winter time you will just be blowing wasted gas heated air outside. Or do like I do in the winter time and reconfigure the fans and let your rigs heat your basement thus helping to heat the rest of the house.

To get back to the op question, 1 blowing in and 1 blowing out and the rig somewhat close to the exhaust fan. Or 2 blowing out if there is another window you can open to allow air flow. Whatever way you do it, you always need the air that is being sucked out to be replaced with the same amount of air that is being sucked in from somewhere, via the main house or a window. Quick and simple example without going into formulas and such: 1 gallon of air being sucked out needs 1 gallon of air being brought in, that’s a 1:1 ratio. 1 gallon being sucked out and .5 gallon coming in = 1:.5, not very efficient. 1:2= over kill but way better than the last.

If you are ducting I suggest pulling the hottest air out from near the equipment instead of the ambient room air.
If you're pushing then push the cold air close to the equipment.
Ventilating the room is secondary to ventilating the equipment.

Oh dang. Thanks for the input guys. . I will probably get another fan and do a push pull. The room is a small 10x8 in the basement. I will try to get air blowing from the basement into the room and vented out... problem being I would want the basement door closed (access is from the outside of the house to the basement. so the air wouldn't be as cold as outside.

So the red circle is the fan I already have. And here is the "plan".  So I shouldn't really have to worry about condensation on the rigs?


The fan by the gpus will be the more normalized/ambient air from the basement. (or would it work better to have the fan by the gpus pull air to the basement? It will probably be a smaller fan. (The window fans are 14" 1400cfm, i think. The fan by the gpus will probably be a small house style fan.)

Sorry, I meant that I added one intake fan as well as the two exhaust/out fans and that solved the problem..  Without the intake fan, there was no moving air and temperature just went up and up... 50C inside is pretty hot and the paint started melting on the walls..  No fires though 

Thats very interesting and maybe i am wrong on this occasion. I am not sure where the hot air would be going if you are only blowing colder air in

I don't fully agree with this but it does depend on the size of your mining operation.  I have 200 GPUs in a 1800 sqft warehouse and initially due to lack of air flow/moving air, the air temperature rose to almost 50C...  and this was with two exhaust fans pulling air out.

Changing the setup to have one intake fan resolved the problem and air temperatures inside now a happy 30C.

Another vote for pulling air out(exhaust fan), if you can pull in ambient air at a cooler temp than the hot air you're exhausting, you'll working your cooling system less.

Pull air out and push cold air in is the best option, if you only have 1 fan then, pull the hot air out, cold air will be pulled in from any unsealed paths.

The best scenario would be to have both. Cold are from outside being pulled in and hot air being pushed out.
The way it is set up will really depend on your location and setup.

But if you only have an option to chose only one, i'd say go for the pull hot air out. Pushing air inwards can only do so much when all the hot air is already trapped inside anyway. Best of luck!

You need to have air moving and from my experience if you have air being pulled in, as long as there is a gap/vent/extraction then it will find its way out - having an extraction fan obviously better..

Having a room with two extraction fans without intake fans will not be anywhere near as effective.

Hey guys,
I wanted some input on how to orient fans for my mining room. I have 1 14" duct fan blowing out the window right now, and was looking at getting a second one. Would it help to have the fan blow cold air in? or keep it blowing hot air out? Or would one blowing in and one blowing out work well? Would that be too humid and cause condensation on the equipment? It'll probably be less than 40 degrees out here consistently in 2-3 weeks and have about 8000 watts of heat dissipating at the moment.
Thanks.