You should be able to do a 4x8 tent no problem, or you could frame a wall and put up some of that 4x8 rigid insulation bored they have at Home Depot and lowes its like $6 to $13 a sheet it has a Mylar reflective coating on one side and a white coating on the other. Probably run you around 150...
I had one for a while their nice at fist but it kills your torch and personally I feel like it made me cough a lot more. Go for a titanium domeless nail.
Just make a mount using some small thick vacuum belts suspended from the ceiling with hooks, attach the fan to a piece of plywood with hooks on the top to hang from the belts. You can do it for less than 40 bucks