I might have a decent suggestion - use some fans made for green houses (I think). and containing and blowing it out - errr the fans are here...
I considered something like this myself at one point, but, I just decided to take my shelf (similar to yours) and put it next to a window and put a outbound box fan in.
https://steemit.com/mining/@yminesandblogs/question-the-mechanics-of-pushing-and-pulling-air
I'm not sure how much air exchange you'll need to keep the machine cool.
Just off the top of my head you could consider throwing a plexiglass box over it and routing a few of these fan in push-pull configuration out a window using the same kind of tubing you used for your exhaust of your AC.
I haven't done this myself so I don't know for sure, I'd look into how much air you would have to move and account for the fact that there might be some distance between the fan on the hose... You know stuff that might require an engineer or HVAC person lol.
upvoted.
RE: Cooling Considerations for Mining