Principle of Cold and Hot Water Power Generation

Principle of thermoelectric power generation

Thermoelectric conversion materials have three basic effects, namely, the Peltier effect, the Seebeck effect, and the Thomson effect, which form the basis of the thermoelectric theory of thermodynamics, and also show a broad prospect for the practical application of thermoelectric conversion materials. Thermoelectricity utilizes the Seebeck effect of materials to transport energy through carriers (electrons and holes). This effect was discovered in 1821 by the German Seebeck: In a circuit of two different metals (antimony and copper), if there is a temperature difference between the two joints, a magnetic field appears around them. Through further experiments, Seebeck discovered that there was an electric potential in the circuit. The Seebeck effect is the basis for thermocouples, thermoelectrics and thermoelectric sensors.

The principle of thermoelectricity is shown in Figure 1: Two different types of thermoelectric materials, N and P, are combined at one end and placed at a high temperature, while the other end is left open and given a low temperature. Due to the strong thermal excitation at the high-temperature end, the hole and electron concentrations at this end are higher than at the low-temperature end. Driven by this carrier concentration gradient, the holes and electrons diffuse towards the low-temperature end, thus forming a potential difference at the low-temperature open circuit end. By connecting many pairs of P-type and N-type thermoelectric converters to form a module, a high enough voltage can be obtained to form a temperature difference generator. This kind of generator can convert heat energy into electricity directly under the condition of small temperature difference, and the conversion process does not need mechanical moving parts, and no gaseous or liquid medium exists, so it is an ideal power source with wide range of adaptability, small size, light weight, safety and reliability, and no pollution to the environment. Temperature difference power generation is flexible, green, quiet and small size of the characteristics, so it can play an important role in many areas.