Peltier effect or Peltier element is a process in which a modular structure of two types of semiconductors sandwiched between substrates made of copper, when current flows, one side radiates heat and the other absorbs heat, so that the hot and cold sides switch depending on the direction of the current. The electronic cell itself is a square plate with about or more than 100 P- and N-type cells, which are usually arranged electrically in series and thermally in parallel.
The modular Peltier structure after supplying electricity to two semiconductor elements, on one side begins to heat up, and the other to cool accordingly. A heatsink is usually added to the warmer part of the module, and depending on the application and environment, maybe even a fan to control the temperature of the module relative to room temperature. The more we want to cool, the more cooling elements we will need to add to the hot side, but this causes the element's efficiency to decrease. If one side happens to be heated and the other side is forced to cool then the device itself starts generating electricity and becomes a thermogenerator or also known as a Seebeck element.
The Peltier element is usually referred to as TEC (Thermoelectric Controller) due to the process of transferring temperature to electric charge, and the Seebeck element due to the process of producing electricity from heat TEG (Thermoelectric Generator). Another characteristic of Peltier and Seebeck modules is that after the designations TEC and TEG there are 5 digits, the first three indicating the number of elements and the second the maximum current. For example, if the element model is TEC-07103, it means that there are 71 thermocouples with a maximum current of 3 A. The degree of cooling of the heated side depends on how low the temperature of the cold side will become. Depending on the type, the application is used in water dispensers, cooler bags, etc.