Hybrid/toggle-able TEC system
I have been interested in TECs for a while now, namely how to integrate them into pc watercooling while minimising the hassle attached to them.
The main issues i see with TECs are; a) their power draw, b) expandability/size, and c) condensation controlling them.
Most people on the internet seem to agree that for every 1w of "cooling" power, 1w of power from the wall must be expended. This means that under full load, my computer would likely use well over 100W, just on cooling; even at idle a noticeable amount of power would be used just to cool it. Contrasting this with a traditional water cooling loop with the same amount of radiators, the only part using power is the pump, the radiators can easily passively dissipate the heat load at idle. While you could simply cut power to the TECs at idle, i do not think the water alone could effectively dissipate the heat without any form of radiator.
The likelyhood of failure in a simple pc water cooling loop is less than that of a TEC cooling solution, moreover, fixing a water cooling loop is more straight-forward than a TEC loop. Moreover, a TEC system physically takes up more space than a watercooling loop, thus in the even of a failure in the TECs, i would likely have to tear the entire system out of the computer or the computer would be unusable until the issue has been rectified.
Condensation and control go hand in hand. Obviously you do not want water settling on your motherboard, thus you would want the water to be above the dew point. I have never been able to come to a conclusion on how to control a TEC such that the fluid never drops below the dew point. I have had thoughts of using the motherboards PWM signal to control the cooling power of the TEC, however, i have been unable to figure out a circuit design. I have thought of using an arduino board to monitor the humidity of the atmosphere in the case and the fluid temperature, and then defined a target temperature based on that, again, i was unsure how to design a circuit to do that. I understand that when using PWM you would likely need a MOSFET, but i am not confident in my circuitry skills.
2/3 concerns i think can be resolved with a design I thought of today; what if you used two (or more) remote irrigation valves to connect and disconnect the CPU cooling loop and the TEC cooling loop? When the computer is at idle, the valves could open and the TECs could turn off, thus the heat produced by the computer would be dissipated by the radiators which would usually be dedicated to cooling the TECs. Moreover, this would reduced the risk of condensation damaging the computer, as the TECs would not be turned on constantly; also if the TECs fail, then the system could be used as a traditional water cooling loop.
My main questions are A) What is the best way to control a set of TECs based on fluid temperature (or something else if fluid temperature isnt the best metric to base it off)?, and B) would a system like this be feasible?