I understand that when cooling water with LN2 directly (through pipes for example), that it can be too effective, freezing the water (and blocking the pipe).
From what I read, regulation of the heat transfer is considered complicated to control. Often employing at least a fixed insulation to regulate the rate of heat transfer.
If I immersed a fixed copper heat sink into LN2, the copper interface would be below $0C$ and still risk freezing the water.
My question is directed at those familiar particularly with Peltier cooling devices. Considering an aparatus, where a Peltier is:
- A) interfaced directly to a flat interface on a heatsink; or
- B) interfaced with a fixed insulation
The following sub-questions apply:
- Does a cooler heatsink on the heated side, improve the max. cooling rate?
- If turned off, would the peltier device exhibit any insulating effect?
- Would there be a minimum operating temperature, in the case where the Peltier was turned off and cooled toward LN2 temperatures?
Given favourable answers to the sub-questions, and any additional comments, the title question would be answered. Some helpful additional comments may relate to industry standard heat-exchanger/regulator apparatus and their performance/cost.
To reiterate the specifics of my theoretical apparatus. The "heatsink" is in the LN2 canister, the Peltier device outside with the hot interface on the "heatsink". When the peltier voltage drive is 0, the peltier would have an insulation effect R1, resulting in a Rate of heat transfer (ROHT) on the coldside of C1, changing the voltage to full on the Peltier changes the insulation effect to a negative value R2, and increases the ROHT to C2. For intermediatary voltages, the insulation effect is between R1 and R2, and the RoHT is between C1 and C2.
- What is R1 (the insulation effect) of a non-specific Peltier device with no voltage applied?
- What would be a guestimate for C1 given an LN2 heatsink?