your question is very vague. You can run a decent size room on 2k's worth of lighting, how many? depends on how well u can fit them in there. The best way to keep the room cool is to use air cooled hoods, it doesnt matter where the air comes from or where it goes, just make sure you have them sealed off from the room. Aside from that u need to way to keep the rest of the room cool, an AC unit would work well, and then u could use a carbon scrubber to pull air from the room and vent it out side, this will keep the air fresh in the room. If your not worried about smell, then u dont need to seal off the hoods, or use a carbon scrubber