Thermoelectric coolers are HOT
Thermoelectric coolers (TECs), aka Peltiers, are solid-state heat pumps that provide spot cooling for electronic components and high-density circuits. They operate on the Peltier effect, which is that there is reversible heating, or cooling that occurs at a contact when current flows from one connector to another.
The Peltier effect is the inverse of the Seebeck effect, also known as the thermoelectric effect, which is the basis for the thermocouple.
The TEC consists of a number of p- and n-type semiconductor pairs connected electrically in series and sandwiched between two ceramic plates. A voltage applies to two ends of the Peltier. This creates a difference in temperature between two dissimilar materials.
With the temperature difference, heat moves from one end to the other. The absence of heat translates to cold. The heat moves from the environment or that which we want to cool and carries through the cooler by electron transport. It exits via the hot side of the Peltier as the electrons go from a high- to low-energy state.
The capacity of the cooler is proportional to the current and is a function of the cooler's size.