Lämpökylmävoimien

Lämpökylmävoimien, which translates to "thermoelectric forces" in English, refers to the phenomenon where a temperature difference across a material can generate an electric voltage, or conversely, an electric current can create a temperature difference. This effect is a fundamental principle in solid-state physics and forms the basis of thermoelectric devices.

There are three main thermoelectric effects: the Seebeck effect, the Peltier effect, and the Thomson effect. The Seebeck effect describes the generation of a voltage when two dissimilar conductors or semiconductors are joined at two points and these junctions are held at different temperatures. This is the principle behind thermocouples, widely used for temperature measurement. The Peltier effect is the inverse of the Seebeck effect. When an electric current passes through a junction of two dissimilar materials, heat is either absorbed or released at that junction, leading to a cooling or heating effect. This is utilized in thermoelectric coolers, commonly found in small refrigerators and cooling devices. The Thomson effect involves the absorption or release of heat when an electric current flows through a single homogeneous conductor with a temperature gradient along its length.

Materials that exhibit these thermoelectric effects are known as thermoelectric materials. The efficiency of thermoelectric devices is determined by a material property called the thermoelectric figure of merit, denoted by ZT. Higher ZT values indicate better thermoelectric performance. Research continues to focus on developing new materials and optimizing existing ones to improve the efficiency and applicability of thermoelectric technologies for energy harvesting and cooling.