Lämpösähköinen

Lämpösähköinen refers to the thermoelectric effect, a phenomenon where a temperature difference across a material produces an electric voltage, or conversely, an electric current through a material can cause a temperature difference. This effect is observed in certain materials, known as thermoelectric materials, which exhibit unique electrical and thermal properties.

The primary thermoelectric effect is the Seebeck effect, discovered by Thomas Johann Seebeck in 1821. When two dissimilar conductors or semiconductors are joined at two junctions and these junctions are maintained at different temperatures, a voltage is generated in the circuit. This voltage is proportional to the temperature difference and depends on the properties of the materials used.

The converse effect, the Peltier effect, was discovered by Jean Charles Athanase Peltier in 1834. When an electric current flows across the junction of two dissimilar conductors, heat is either absorbed or released at the junction, depending on the direction of the current. This allows for heating or cooling applications.

Thermoelectric devices, such as thermoelectric generators (TEGs) and thermoelectric coolers (TECs), utilize these effects. TEGs convert waste heat directly into electricity, offering a way to improve energy efficiency in various applications, including automotive, industrial, and aerospace sectors. TECs, on the other hand, are used for solid-state cooling and heating without moving parts, finding use in small refrigerators, temperature control systems for electronics, and medical devices.

The efficiency of thermoelectric devices is largely determined by the figure of merit, ZT, which depends on the Seebeck coefficient, electrical conductivity, thermal conductivity, and temperature. Research continues to focus on developing new materials with higher ZT values to make thermoelectric technology more practical and widespread.