Thermoelectric effects refer to a set of physical phenomena where heat energy is directly converted into electrical energy, or electrical energy is used to create heating or cooling, without the need for moving parts. These effects are based on the behavior of charge carriers (like electrons) in materials when exposed to temperature gradients or electric fields.
The three main thermoelectric effects are:
- Seebeck Effect:
When two different conductors or semiconductors are joined and their junctions are kept at different temperatures, a voltage is generated. This is the principle behind thermocouples, which are used to measure temperature or generate electricity from waste heat. - Peltier Effect:
When an electric current is passed through the junction of two different materials, it can absorb or release heat, causing one junction to cool and the other to heat up. This is used in thermoelectric coolers (like those in portable refrigerators or spacecraft). - Thomson Effect:
This effect describes the heating or cooling of a conductor that carries current through a temperature gradient. It is generally less pronounced than the Seebeck or Peltier effects but is important in precise thermoelectric analysis.
Applications of thermoelectric effects include:
- Power generation from waste heat in industrial processes or vehicle exhausts,
- Solid-state cooling without refrigerants or compressors,
- Space probes (e.g., NASA uses thermoelectric generators in deep-space missions),
- Temperature sensing using thermocouples.
Thermoelectric technology is valued for being compact, silent, and reliable, though improving its efficiency remains a major area of research.