a Thermo-Electric Cooler. aka Peltier Cooler, has a 'hot' side and a 'cool' side, you apply voltage across it, and it makes the 'cool' side cooler, and the 'hot' side hotter.
so the cool side goes on the cpu, which gets actively cooled by the TEC.
and the hot side goes onto a heatsink (or water block), and transmits its heat to the air (or water).
if your heatsink (or water cooling system) can shift the heat quick enough, you get a very cool cpu
.
here endeth the lesson