power source

[pyrogeek]

As long as you hook it up to a big enough expansion chamber it should not cool ur chamber so much.
Co2 is only cold when its changin forms(tell me if im wrong but im pretty sure)

Well, when it changes from a liquid to a gas it gets colder since the pressure is dropping. I believe there is some law that states that.

Any gas will do this. CO2, butane, propane, etc. In a diesel engine it works like this also, the pressure inside the combustion chamber increases and thus creates a lot of heat to ignite the deisel fuel.