How does the Peltier effect allow a thermoelectric device to pump heat?

The Peltier effect allows a thermoelectric device to pump heat by utilizing the absorption or release of heat that occurs at the junction of two dissimilar conductors or semiconductors when an electric current is passed through them.12

In a practical thermoelectric device, multiple thermocouples—often made of n-type and p-type semiconductors—are connected electrically in series and thermally in parallel. When a direct current is applied, a temperature difference develops between the junctions: heat is absorbed at one junction (causing cooling) and released at the other. By keeping the hotter junction at a low temperature through external heat removal, the second junction can become significantly colder, effectively acting as a refrigerator to pump heat away from a specific object or environment. This process is reversible, distinguishing thermoelectric power generators from many other energy conversion systems.234