I came across a used Coleman 12-volt cooler at a flea market today. I've been wanting to dissect a small dorm refrigerator or freezer for some time now to experiment with cooling options, and here was one that was already set up for 12-volt DC. At $20 I couldn't pass it up.
The first thing I noticed while testing it was that it would heat as well as cool, depending on how you hook the power wire to it. "Must be a heat pump", I said to myself.
I cracked the top cover off to find this tiny blower and an aluminum heat sink.
Now I knew I wasn't going to find the tiny compressor, condensor and evaporator that I was hoping for. After much prying I popped the heat sink off and presto! Peltier.
After complete disassembly here's what I ended up with. (I've removed the motor already as it was not needed and very noisy.)
I must not understand the Peltier setup. I thought when power was applied one side of the plate got warm and the other side got cold. When I turn this one on one side gets warm and the other side gets hot. I reverse the connections and the sides reverse. There was another heat sink on the bottom of the plate inside the cooler so it's obvious how it was supposed to work, but I'm not seeing how it will cool anything if both sides get warmer than ambient. Maybe the reason the warm side gets warm is because I don't have a heat sink on the hot side and the heat is bleeding through? If I can take the heat away from the hot side effectively will the warm side drop below ambient? Can someone educate me? Or is this thing just broken?