The peltier device worked well when i submerged the hot side in a frozen alcoholic gel, but then when i unplugged it from power and washed the device with water it stopped working. It doesn't get hot nor cold. The temperature never went above the temperature limit written in the datasheet, so i don't think i burned it. The seal around the device looks waterproof but is it possible that water got inside and shorted the P-N junctions? Or could the alcohol have damaged it somehow? Is there any way of fixing it?
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\$\begingroup\$ When it's stopped working, what do you actually observe? No current at all? Power supply dropping out from short circuit? Some current? Heating of both sides? \$\endgroup\$– nanofaradCommented Apr 26, 2022 at 20:09
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\$\begingroup\$ Does it still pass current? Perhaps alcohol from the gel penetrated, then the washing made it worse. \$\endgroup\$– Solar MikeCommented Apr 26, 2022 at 20:10
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\$\begingroup\$ The temperature on both sides stay at room temperature, and the power supply doesn't trigger its short circuit protection. It used to take 0.5 amps but it takes 0.03 amps now. \$\endgroup\$– Mahdad BorhaniCommented Apr 27, 2022 at 8:01
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The coefficients of thermal expansion (CTE) of different materials can fracture at the interface connections when thermally shocked too fast to allow a smooth shrinkage with cooling and reduced stresses. Now you have experience.
tl;dr but added FYI
Stress is a force, Strain is displacement.
Below shows that with gentle cycles the strain can accumulate after 28 cycles with the rate used in that test.
Your test was obviously much faster dT/dt and much higher resistance as a result.
https://thermal.ferrotec.com/technology/thermoelectric-reference-guide/thermalref10/
", thermoelectric modules should not be installed using solder or epoxy whereby an object is rigidly bonded to the module. Unless the thermal coefficients of expansion of all system components are similar, rigid bonding combined with temperature cycling often will result in early module failure due to the induced thermal stresses."
