Thermoelectric cooler (TEC), which was first found by Peltier in 1834, is a semiconductor material as the foundation, and it can be used as electronic components of a small heat pump. Through loading a low DC voltage on both ends of the TEC, the heat will move from one side of the element to the other. At this time, the temperature of one side of TEC will be reduced, and the other side temperature will rise. It is worth noting that, as long as the direction of the current is changed, the direction of heat flowcan be changed and the heat will be conveyed to the other end. So TEC can realize two functions of refrigerating and heating at the same time. In addition, TEC can also be used to control temperature precisely.
We take a typical single-stage TEC as an example. And we put the TEC on the radiator and keep it in the room temperature. After that, we link it in an appropriate current or DC power supply, and the clod side temperature of TEC will drop to about -40 degree. At the moment, the TEC will reach relative thermal equilibrium state, and the temperature difference of both sides of TEC can reach maximum (DTmax). If the cold sideis input constantly, its temperature will increase gradually, and it will stop increasing until the temperature of hot and cold side are the same. By this time, the refrigerator will reach the maximum cooling capacity (Qmax).
