Thermoelectric refrigeration system is based on the Peltier effect.

Explanation:
The Peltier effect, named after Jean Charles Athanase Peltier, is a phenomenon in thermoelectricity where a temperature difference is created at the junction of two different conductors when an electric current is passed through them. This effect can be used to create a refrigeration system, known as a thermoelectric refrigeration system.

Working of a Thermoelectric Refrigeration System:
A thermoelectric refrigeration system consists of several thermoelectric modules, also known as Peltier modules, which are made up of two different types of semiconductors (usually n-type and p-type) connected by metal conductors. The modules are arranged in an array and placed between two heat exchangers.

When a direct current is applied to the thermoelectric modules, it causes electrons in the n-type semiconductor to move from the hot side to the cold side, while the electrons in the p-type semiconductor move in the opposite direction. This movement of electrons generates a temperature difference across the junction of the two semiconductors.

Peltier Effect:
The Peltier effect is based on the principle that when an electric current flows through a junction of two dissimilar conductors, heat is either absorbed or released at the junction depending on the direction of the current flow. This effect is reversible, meaning that if a temperature difference is applied across the junction, it will generate an electric current.

Heat Absorption and Heat Release:
In a thermoelectric refrigeration system, the heat absorption and heat release occur at the two junctions of the thermoelectric modules. When a current is passed through the modules, one junction absorbs heat from the surroundings, resulting in a cooling effect, while the other junction releases heat into the surroundings.

Cooling Effect:
The cooling effect is achieved by maintaining a temperature difference between the two sides of the thermoelectric modules. By removing heat from the cold side, the system can achieve low temperatures, making it suitable for refrigeration applications.

Advantages of Thermoelectric Refrigeration Systems:
1. Compact size and lightweight compared to traditional refrigeration systems.
2. No moving parts, making them more reliable and requiring less maintenance.
3. Ability to cool or heat by simply reversing the direction of the electric current.
4. Environmentally friendly as they do not use refrigerants that can contribute to global warming.

Overall, the thermoelectric refrigeration system based on the Peltier effect offers a unique and efficient way to achieve cooling and refrigeration, especially in applications where compact size, reliability, and environmental considerations are important.