Congrats on your move! I think moving computers into a closet or something equivalent is really the only solution for dealing with the noise - and to that end (due to space limitations) I opted for an IsoBox from Sound Construction and Design. This is basically a mini closet on wheels, but with the added (and very important) element of ventilation.
I agree with the previous reply- ventilation into the enclosed area is much more the issue than heat dissipation from within the computer(s). The key is not letting hot air build up or increase the operating temperature of the enclosed environment.
I found the IsoBox very sufficient in terms of bringing cooler room temp air (from the floor) - btw, it really helps if you have this on a wooden floor vs. carpet - BUT, I was having problems getting the air out of the unit, so I hired a professional AC contractor and they installed an "extraction system" which pulls air out of the unit via ducting. Kind of hard to explain, and EVEN if I was using a closet, the same factors would apply.
The advantage of a closet, albeit limited, is that you probably have more cubic feet to deal with, but regardless, you need to ensure airflow. Replacing warm air with cool air is the key, and natural convection only works to the extent that the air has some place to go.
For what it's worth, I took the top off my primary rack mounted computer in the IsoBox... didn't make that much of a diff.
Here's a picture:
Hope this helps!
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