If I were using a window a/c unit with a tent I would cut a hole in the side of the tent the size of the a/c. Install the a/c in this hole just like you would a window, half in and half out...the 2 halves are sealed in between. Build a plenum off the back as mentioned and run ducting, Personally I would go with an 8" fan with an 8" inline fan for 12,000 BTU, a 10" for 18,000 BTU and a 12" for 24,000 BTU. Not putting a booster fan will make the unit less efficient (run longer per hour) for sure, but at the same time the fans uses energy as well (2-2.5 amps) for an 8"....but much less than the 8-9 running amps that a 12,000 BTU uses. Keep in mind you are limited to the flow of the booster fan and don't forget you need make up air since you are pushing air out of the room. With no make up air you will pull a vacuum and your a/c wont work properly. If you have a window crack it open a couple inches which will allow make up air. The a/c will draw air from the side vents usual. This air will NOT be coming from your tent so it won't deplete the co2, only exhuasting the room air that comes from the opened window. The half of the a/c that is inside the tent is sealed from the back half. The front half brings in air from the tent, chills, dehumidifies, and put that air back in to tent. The keeps most of the smells from escaping and it also keep most of the co2 inside the tent. If exhasting smells is a problem put in a carbon filter inside the room iteself since, not the tent. OR you can put an inline filter on the 8" duct as long as you are using a booster fan.
