[Kevin Sevcik]

First, I thought MEs were all about heat transfer. I know I had to learn entirely too much about it in college.

At any rate, I'll add to the chorus. I really think ambient air is your best bet, since anything else requires expending relatively large amounts of (electrical) work in order to cool below ambient. Simple thermodynamics and all that.

Thinking about it, you could just make a rechargable cooling unit, however. Just something you put a piece of dry ice in and it provides enough cooling to last for a few hours. If we could get an estimate on how much current the whole ammo-bot draws we can figure out how much dry ice you'd need. In fact, an estimate of the power draw would be useful for figuring out any cooling solution.

So... basically, what size batteries are we talking about, and how quickly do they get drained?