I am a happy new owner of an antminer s9. I am having issues with exhausting the heat from the room it's in. I wanted to re-purpose an existing exhaust duct which was a 3" duct. I connected the antminer to the 3" duct and it got over 100°c so I was very unhappy with this. I don't know very much about hvac or cooling, but I've done some research and it seems that the antminer s9 pushes ~200 CFM. A 3" duct maxes out at somewhere under 50..so the size is nowhere near adequate if I am reading this correctly. Now I was looking at getting a 5 inch round duct, but this chart I'm reading again says 5" maxes out at 50 cfm.
Basically my question is will a 5 inch duct allow enough airflow to cool my miner? It is a short run that goes straight outside, but 3" wasn't enough.
http://buildingincalifornia.com/wp-content/uploads/2014/03/duct-sizing-chart.pdf I was using this chart for CFM
Thanks
Chart is not good as it does not take fans strength into account .
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If you can do a six inch duct you will be fine for 1 miner.