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My mining room currently has 30 gpu's running.  Room is 1680 cubic feet.  I have two windows and have purchased two of these ...

https://www.build.com/air-king-9166/s380951?uid=441363

One to pull air in and one to push air out.

On the low setting it does 2510 CFM.  If you do the math it comes out to be about 89 air changes per hour on the low setting.  2510x60=150600/1680=89.64

Currently it is about 22C outdoor temp.  Ambient temp of the mining room is around 38C.  This is with both windows open.  Mining room door shut.  I have a cheap box fan in one window pulling hot air out.  No fan in the other window right now.  All five 6-gpu rigs have a cheap 20" box fan behind them and my gpu temps currently range between 59C and 70C.

Summer time outdoor temps sometimes reach 37C on the hottest days of the summer.  Average is probably between 26-32C.  Are my ventilation plans going to be sufficient?  How does humidity play into it?  Sometimes we have some pretty humid days during the summer here.

The other thing I've thought about is portable air conditioning, but everything I've read says that it's way more important to propertly ventilate than it is to cool the air.

You are going to have problems with the humidity condensing on the circuit boards of the GPU's.  Not good.  Bringing in humidity with a fan is not a wise idea considering the condensing problem and the fact that it is the humidity that carries heat.  An air conditioner is actually a dehumidifier.  Thats how an a/c unit gets rid of the heat from in your home.  You would be better off with a properly sized window a/c unit exchanging the heat to the outside (via the condenser coil) and it removing the humidity out of the room at the same time.  Sure its another power bill but sure beats a 30gpu replacement bill.

At what humidity percentage does this become a problem?  Currently the ambient room humidity is 10%.

You actually need humidity to avoid static discharge.  I think anything under 40% is fine.

How exactly will he get condensation when the GPUs are much warmer than the ambient temps? Use your brain here. The GPUs will NEVER be below ambient without some kind of chiller or sub zero cooling method.

Take a hot cup of coffee outside in the winter. Let me know how much condensation builds up on the cup.

In the Datacenter I work at we keep relative humidity at 38-42% any more or less can be hazardous to the equipment. I have seen motherboards fry from static shock in dry environments.

your issue is air flow.

those fans  should both be exhaust  and in intake just an  open window.


    opening only >>>>>>>>>>   gear  >>>>>>>>>>>>>>> 2 fans

this means  one thing can you fit  2  fans into the exhaust window?

and just leave the other window wide open?


you do realize   the windows should not be on the same  wall?


this is good

https://i.imgur.com/FVLlbdq.png


this is bad
https://i.imgur.com/OqSjeQc.png

That says it runs 3500 cfm @ 170 watts.

I bet you get 1500 cfm max.

The issue with these fans are they are not meant to be run 24/7 at high temps.

Look at Quietcool fans

Phillip,  Yes both windows are on the same wall.  I see what you're saying ... So what about using the windows for air intake and exhausting through the ceiling into the attic of my house?

That's probably your best option tbh, considering your window arrangements.

This is what I was going to suggest after reading the OP. Passive intakes are what you want, let the suction of your exhaust pull the air through the room.

Nice! But pretty expensive. 

https://shop.wholehousefandeals.com/quiet-cool-classic-line-fans.aspx

How do you calcualte the cfm or air changes per hour you're going to need for a specific number of gpu's?  Or do you do it some other way?

In my opinion,  I think the use of a fan and a building with more windows would be a better alternative in contrast to an AC..in terms of cost of operation, I think AC are expensive to operate and maintain in this part of the world... I think with proper ventilation and air control one can manage a mining rig without fear of overheating..

A buddy of mine tried mining in his apartment which had a similiar layout as yours and he also had issues. The problem was the layout of the windows in his living room where he kept his rigs. Basically he tried various fans and putting the GPUs in different areas of the apartment and in the hot summer weather he basically had to shut down the rigs.

It would be best if you have a cross-flow ventilation setup, where you got a window on one end and another window on another, in most apartments you won't have this however.

One other thing you can do would be to just put all the GPUs in enclosed server 4U chassis and just have some ducts which are intake and exhaust and this would solve the issue for sure, and the place would be at least livable, I don't know how you can eat and sleep in a room that hot.

Just go on like Craislist and buy some old cheap server 4U chassis and you can put 6 GPUs in each chassis. And go to home depot and buy some ducts and you should be good.

Best option is Air Conditioner. Bad news is bye bye to part if not all of your profit mining whatever coin you are mining at current prices.

Considering you may be mining ETH (if you have AMD cards), it's probably going to be something like this: A well balanced mining farm with 30gpus would do like 900-930 mh/s. It will use up to 3900-4000W from the wall. Add to that another 1000W from air conditioner.

This way, your profit will be around 60$ per month. But you´ll have to roi your A/C this way. So, for the next months, you´ll have no profit.

I had a 1x6 gpu and 1x4 gpu mining rig. It was pulling around 1450W from the wall. RX 580's and 570's. 1150mhz core 2250 mem , custom mem timings , all between  837 and 881mv (depends highly on ASIC quality). they would not do anything below the mv i applied since they crashed. I didn't want to reduce mv on memory from stock, since it affected stability and didn't want to deal with two unknown issues if troubleshooting. my ambient room with 2 normal fans spinning to move air directly to rigs and a window of 130x120 fully openned with no glass was something around 32ºC with 90% humidity and 42-45ºC outside in the hottests days (i live very near the sea). The rigs were in the room of 3x2,6 meters with good airflow. Oh, by the way, i never had to put more than 60% rpm fans on the them. just on one shitty MSI RX 580 armor that has a below average performance, not as overkill as Sapphire Nitro+ 580 and 570. Temps on cards were from 50ºC on most RX 580 Nitro+ to 70ºC on the MSI.

So, prepare to sweat hard this summer unless you want to put AC and get rid of part of the profit. Your profit may vary if you are mining other coins than ETH, but in essence the same picture applies to almost all coins in the market right now.

The room humidity is poor, it needs proper ventilation and the temperature of the ambient has to be further brought down. I understand that an air-conditioner is an additional cost on the electricity cost, there are power savings air-conditioners. The equipment must be protected from overheating and damage for utmost performance.  

You are wrong here. Modern AC control humidity as well. They do not eat too much electricity. At least, it will be much more profitable to use this system to avoid the problems which are discussed by the author of this topic. Fans (even if you use 3-for of them) will not work well, especially in the summertime.

I ended up going with one of these in the ceiling to pull air out of the room ...

https://quietcoolsystems.com/products/classic/

And one of the Air King window fans (linked above) to pull air into the room. It's been working great since the spring of 2018. A year later and I'm about to enter my second summer of mining.

Nicely done! I was about to refer that to have maximum efficiency you need to exaust heat through the top of the room (as hot air rises). This way, the colder air will get in through the wall window and hotter air will rise to the ceiling and get exausted
As for the humidity that someone mentioned, no worries mate, the hot boards will never allow condensation ...  ;D

Balancing it with cost is another thing..

I prefer natural air flow than air conditioner for cooling a mining farm, you need to buy big exhausting fan if you are running multiple rigs, make more space for good airflow and use exhaust fan to get rid of heat, works better than A/C for me