Im trying to figure out what the total cfm is for an asic miner…(lets go with a Bitmain L7 9.5 t/h)
So there are 2 intake fans and 2 exhaust fans and each fan is 320 cfm. What is the total cfm that is coming out of the exhaust side, is it 640 cfm per exhaust fan??
The total exhaust side of 1280 cfm??
We base everything off of 500cfm/miner. Our hot rooms have exhaust fans 20% greater than that to create negative pressure. So 20 miners is 10,000cfm and our new fans are 13,400cfm so we went above 20% on those.
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IMO the intake is in the way and a waste of power, Make the exhaust pull the air. The fans running intake produce heat and thus slightly heat the intake air. Exhaust pulls. If the exhaust pulled at 100 cfm and intake is 10 cfm , the system is still 100 cfm because exhaust will just pull past the intake. I assume your L7 has mounted forced intake, so it is what it is.
I always look at volume of air , as the big factor. If we took the figure you supplied above and put that on a rack in the middle of a warehouse , big woop. Where as if we put those same figures into a tiny room ( say 4’x4’x 8’ h, 144 cubic feet) your 640 cfm exhaust will clear the room 4 times per minute.
Then the issue becomes the temperature of the intake air more than the temp of the unit or exhaust. And always jerry rig some sort of intake filter. Even if that means just buying a 2’x3’ filter at home depot and stapling it over a window.
Confining your space and dictating intake temperature are key IMO. Old tricks like ‘hot goes up cold goes down’. So don’t have your miner sitting medium height in a room and expect thermal dynamics. Intake should be feeding from below (cold) and exhaust should draw from the top of the room and immediately exit. (don’t leave hot aluminum foil ducts running around your room, they are in essence heaters).
Another big trick to temps is relative humidity. quoted from the internet > " As air temperature increases, air can hold more water molecules, and its relative humidity decreases. When temperatures drop, relative humidity increases "
You can buy a small ($40) dehumidifier from Amazon and place it inside your intake ducting. Thus lowering humidity before the air enters the room, thus limiting the thermal transfer of temps to air and slightly cooling the room. The de-humid’s run at about 40-100 watts, so they are easily cost effective.
(side note) jerry rig a tube (with hot glue/super glue) to the dehumidifier to auto-dump the reservoir (like out a window or whatever)
I realize you’re talking specs on the unit. But in due time, you will be clearing the air in that room, then that facility (your house). Air control is one of those issues, rather cheap and every time I wish I nipped it in the butt before I got too deep on other fronts. A top notch air set-up is cheap compared to mining gear.
If cooling becomes a deal, I recommend https://www.vortec.com/en-us/ , That is a pneumatic cooling unit, pretty different, but highly used in trade jobs. The reason Vortec is top notch is because it provides cold air with near zero % humidity. It’s a miracle product/item if you’ve never seen one. Blow air through it, it comes out colder.
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