Where to put the air compressor?

They produce heat and need air to compress. If you build a box you are screwing the pooch on both of those.
In my situation with the door closed, it gets to about 80-85 degrees only if I'm running the sandblaster. That's a lot cooler than the ambient 95-100 degree temperatures in a typical Missouri summer. The "funnel" has a 1.5" tube running to the outside, so that may be providing enough air for the compressor. No problems in 7 years, so far.
Rick