Originally Posted by ICYUNVME
Phase change refers to using a basic refrigeration cycle to cool the cpu or to cool the condensor of another stage (in the case of cascade). The evaporator head is special made for the system to utilize such a small surface area efficiently. Yes you will get sub zero temps with the right system and with it running optimally. Condensation occurs when ambient air comes into contact with an object below ambient temperature. The water vapor in the air condenses out of the air and onto the surface. Water and energized circuits is bad juju. I would suggest taking a gander at extreme systems as they have many guides on every aspect of phase change as well as pics that explain the basic refrigeration cycle. I believe the forum you are looking for there is extreme cooling.
We have a section of the forums dedicated to Phase Change under cooling methods.
EDIT: Oops, Niko beat me to it.