Thermoelectric modules are solid-state devices designed for thermoelectric applications. They typically consist of P-type and N-type semiconductor materials connected in series. When an electric current passes through the module, a temperature gradient is established, leading to one side of the module becoming cooler while the other side becomes hotter, known as the Peltier effect. This makes thermoelectric modules useful for various applications, including power generation, cooling, and precise temperature control in a compact and reliable manner.