Lot of problems with this idea:
1) CO2 is R744 not R707
2) You can't condense CO2 in a single phase system, so you'll need to use some sort of cascade. Take a look at the condesing pressure of CO2 to get an idea what I mean.
3) CO2 is a pain to work with since it becomes dry ice rather easily.
4) You can't possibly expect a standard case (let alone one using hot glue!) to withstand that kind of pressure. Yes your evaporating pressure would only be about 1 ATM. But were you ever planning on turning it off and letting the low side be pulled to high side? Would the entire system detonating as soon as theres a power failure and the compressor switches off be a problem for you? If so . . .
5) You're going to be a LOT colder then 0C. More like -70 to -100 C depending on what your evaporating pressure is. You'll probably kill the board with those temps.