Quote from: cheet on May 12, 2017, 07:01:06 AM

Quote from: delicopsch56 on May 12, 2017, 06:29:15 AM

Quote from: cheet on May 12, 2017, 01:52:04 AM

Hi guys hoping to get some feedback on my room plan:

https://i.gyazo.com/d73e124bf0a2ce32e0198c927a095e8f.png

#1 is my current plan: pull cold air in from the window and push them over rigs with fans behind each rig, then pull hot air out from the front of the rigs and use an exhaust fan in the ceiling to collect hot air and exhaust it out of the roof. This should be sufficient cooling for about the ~105 GPUs I can fit on that shelving unit

HOWEVER! I would like to leave open the possibility of expanding in the future without having to move the exhaust fan's ceiling location. So I was wondering if #2 would work if I double my size. As you can see I'd be using fans on the ground to push the incoming air up at all the rigs but I'm unsure if that 15 ft (4.5m) is too much distance to hope to carry the air.

Fwiw, I'm dealing with 75-85 Fahrenheit (24-29c) ambient temps

Any thoughts would be appreciated!

Getting this as efficient as you can is HVAC math. I'm good enough at HVAC to be dangerous, but I do my own work and haven't ever screwed anything up majorly. Your most limiting factor is probably input and exhaust air volume of the room based on the opening sizes. I'd calculate that first and then the fans you have pushing the air over the rigs may be an issue or a bonus, but if those are portable, easy to cope later. You want input and exhaust as far away from each other in the room as possible. Ideally you also input from near or in the floor and exhaust from the ceiling or very near as well. Guessing is why most home cooling systems are inefficient, almost nobody nobody does the math, they just slam in a too big or too small system and cash the checks.

What type of fans are you going to use for input and exhaust?

My room is about 17x12 ft.

My window is 54x34 in and I was going to mount one of these 3150 cfm fans in the window (next to the screen) for pushing air in: http://www.homedepot.com/p/Ventamatic-20-in-High-Velocity-Floor-Fan-HVFF-20UPS/202795625

And this 5000 cfm fan for air exhaust in the ceiling.: http://www.homedepot.com/p/iLIVING-5000-CFM-Power-30-in-Single-Speed-Shutter-Exhaust-Fan-ILG8SF30S/207174738

I just learned its supposed to be a 2 to 1 exhaust:intake ratio so maybe I should find a slightly less powerful fan for air intake?

The fans I am planning to use behind each rig is the 550 cfm version of this fan, easily portable so yeah I can cope with issues pretty easily: http://orionfans.com/products/dc-fans/item/od254.html

In the front of each rig I was going to put a line of 5 x 180 cfm fans where the GPUs end

I didn't know the exhaust should be far away from the intake as possible. I thought I could put the shelving unit right by the window (close to the cold air) and use tarps to control the hot air side and try to exhaust it immediately right there.

Appreciate any advice!

In a closed room, yes, you want BOTH those rules goin on if you can. I think I'd put the heat generator right smack in the middle of thee room.

The home depot cheaper fan, spent that kinda money on fans and ran em 24x7 and dead in 2 years or less That's why I turn my wife's off every morning. Ain't no wind tunnel.

Go stand in front of 3500 - 5000 cfm fans at home depot or lowes, get 'em to plug em in for ya. I don't think you'll be real impressed. Ain't no wind tunnel. Could be enough but won't know without including size of openings and cfm in the calcs, and prolly also BTU or estimate, avg ambient air temp outside and inside with no heat and cool running at all, etc. Attic fans are awesome IF you open every window in the house, yer air isn't dirty, and you have a high temperature differential inside versus in. Like 20-30 degrees. That one is not much more expensive than a good bathroom exhaust fan nowadays. I think you are mostly paying for the metal there.

It could work but you don't wanna overspent or underspend to get the job done.

Most HVAC forums are filled with tradesman that don't really like to give DIY advice in varying degrees but since you aren't working on a furnace or an air conditioner at all they may point you right at the correct formulas if you include all the measurements mentioned in this thread.

delicopsch56

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