I see someone in this thread said ~6400 cfm per Antminer S9? The stated rate is 220CFM, which is correct?
Its 220 CFM. Widely known and tested figure for S9's.
6400 CFM is ridiculous. As an example, the Bugatti Veyron at over 300 km/h on the high side of the power curve, takes in 45000 CFM. Additionally a 737's engines each pull in 2M CFM at max thrust, which would mean you could power a 737 by strapping on 300 miners.
...hell, with the 300 S9s on each wing, and a couple solar panels glued to the fuselage, we would have a self powered plane that literally pays people bitcoin to fly on it.
or not.