You won't need natural gas to generate heat for the AC. The heat can come from the CPU itself. This sounds like a good project for a CPU cooler.... The trick is preventing condensation from getting on your CPU/Motherboard.

Spoiler alert: I enjoyed the movie overall. Loved the action and joker was great. However there were some major plot holes. 1. When batman rescued what's her name in the Fund Raising scene ... wasn't joker still at the top of the building with all of the people? What happened with that? 2. Who put Harvy Dent and what's her name in the oil barrel rooms? Joker said he didn't do it. (This one's an interesting plothole and I think the hint "What time is it?" might have given it away ...) Maybe I'm reading more into it than there is. Possible villain for 3rd movie? I also felt that the fall of Harvy Dent to Two-Face wasn't that believable. I believe the movie needed more attention to detail there. The scenes with him felt kind of rushed.