Originally Posted by Reikoji
Originally Posted by kaseki
One would want to include a controller that kept the liquid above the dew point of the room air. For most this would avoid needing to use ethylene glycol for a coolant liquid. If water condenses on the lines over the motherboard, one might expect ill effects on the processing. (I think this is why the LN2 people wax their boards.) With enough condensation, we are back to leak mode with respect to everything below the PC, such as furniture, books, floor, etc.
That is a possibility. I'd just go with using ethylene glycol for the liquid. Could test it out by operating a system thats not attached to a PC and see if the lines build up condensation.
My intended point is that to have a refrigeration based cooler that is practical for a range of circumstances without big flaws like causing physical damage from condensation, some complexity is needed in the refrigeration control system. In an aerospace system of this type, control of refrigerant flow using solenoid valves and of condenser air flow using fan power control would be expected, along with attendant temperature sensors and control processing. Dynamics of CPU heat output changes would have to be accounted for in the control loops to assure that the refrigeration system's reaction time was fast enough.
For a low cost approach, it might be sufficient to maintain a reservoir of liquid that both the CPU coolant loop heat exchanger and the refrigeration heat exchanger (evaporator side) sat in, and a refrigeration loop that attempted to keep this pool at a given temperature using a simple compressor on-off control (like a typical home refrigerator/freezer). The pool volume would have to be large enough (as a thermal mass) that the two loops could operate independently and still achieve reasonable temperature stability.