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Heat sink mystery Answered

While harvesting parts from a tiny refrigerator, I found something that I don't understand. There was a heat sink about 6 inches square on the back with a 12v fan attached. Underneath this arrangement was a smaller heat sink about 3 inches square and sandwiched between the two was an aluminum block, also 3 inches square and about 1/2 inch thick. Between the block and the large unit is what appears to be a ceramic tile about 2 inches square, seperated from the larger sink with a thin layer of white foam. This tile is glued very securely to the back of the larger heat sink.

What puzzles me are the two wires running from a PCB to the ceramic tile. They disappear into the foam but I can't tell what they connect to. A heat sensor that is attached to the large sink, perhaps? There was a twist knob inside the unit that allowed you to adjust temperature from Min to Max. I don't want to pry off the tile just yet in case this might be something useful in its current condition.

This refrigerator is probably more of an ice chest than anything, else. There are no coils on the back and no compressor. The only motor is what drove the fan. There is a drip pan on the back and what looks like a plastic hose connection but I don't know if this tube let water in or out. The whole refrigerator is only about 2 feet cubed. It was powered by a standard grounded AC cord.

How did this thing cool? And what do those mysterious wires under the ceramic tile serve?

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Boy Genius

7 years ago

Thank you. That explains everything very nicely.

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caitlinsdad

7 years ago

look up "peltier" coolers.