Nice. Bitmain have s19k on their site just now, 120T for 2700W - 23T/J, $2500, seems like a good deal compared to the s19xp at $33/T for 21.5T/J efficiency.
Have you considered hydro units?
that box has a water curtain and we know to filter the water in to stop sediment.
we will do air cooling and water curtain.
Phil, I am not sure if this was already discussed somewhere or you have searched about it but in this project you can also try out "air curtain". These are not meant for the cooling purpose but for avoiding the entry of bacteria's, solid particles and other type of contaminant into clean rooms in the pharma industries. I know this because I am trying to understand the mechanics behind different ways of cooling the mining rigs.
In case you have dirty water and bad filtration system around the area then you can option out for the air curtain and certainly do some "experiments" with it.
An Air Curtain is either horizontal or vertical and is fitted to entrance/door.
What a miner can do is project the vertical air curtains in such a way that they will throw out the hot air out of the mining box area. The conventional fans are not proper fit because they are big, circular and their sizes limit the "surface area" they can cover.
Have you ever experimented on this or do you think it can be good strategy for the up rising miners? May be bigger farms too.