Seebeckilmiötä

Seebeckilmiö, also known as the Seebeck effect, is a thermoelectric phenomenon that occurs when a temperature difference exists across an electrical conductor or semiconductor. This temperature difference creates a voltage across the material, which can then be used to generate electric current. The effect was first discovered in 1821 by Thomas Johann Seebeck, who observed that a compass needle deflected when a circuit was formed by two dissimilar metals joined at two points, with one junction heated.

The Seebeck effect is a direct consequence of the behavior of charge carriers within a material. When one part of a material is heated, the charge carriers in that region gain more kinetic energy and tend to diffuse towards the cooler region. This diffusion creates a charge imbalance, resulting in an electric field and a measurable voltage. The magnitude of the voltage generated is proportional to the temperature difference and a material property called the Seebeck coefficient. Different materials have different Seebeck coefficients, and some materials are more efficient at converting heat into electricity than others.

Thermoelectric generators (TEGs) utilize the Seebeck effect to convert waste heat into electricity. These devices are composed of numerous thermoelectric modules, each containing p-type and n-type semiconductor materials connected electrically in series and thermally in parallel. When a temperature difference is applied across the module, a voltage is generated, and when connected to a load, current flows, producing electrical power. TEGs have applications in various fields, including power generation from industrial waste heat, automotive exhaust systems, and even in space probes where solar energy is limited. However, the efficiency of current TEG technology is relatively low compared to other energy conversion methods, which remains an area of ongoing research and development.