Peltier Element

The basic component of a Peltier device is the Peltier element. A Peltier element works like a thermoelectric heat pump, transferring heat from one side face of the element to the other when DC voltage is applied. One side face of the element is cooled in the process, the opposite side face is heated. When the voltage polarity is reversed, it also reverses the direction of the heat transfer. Thus Peltier elements can be used for heating and/or cooling. The desired heating or cooling power is reached by interconnecting multiple Peltier elements.

A Peltier element usually consists of two square ceramic plates with small blocks soldered between them, alternating between p- and n-type semiconductor material. The blocks are connected by copper bridges that also serve as thermic contact surfaces to the ceramic plates. P-type semiconductors transport the heat in the direction of the current (downstream), while n-type semiconductors transport the heat against the direction of the current (upstream). All blocks are connected in series, alternating the different types of doping. So an electric current pumps heat from one side of the Peltier element to the other, creating a temperature difference between the ceramic plates.