Thermoelectric module can be used as cooling system using Peltier effect. The principle is to get a heat flux between the junction of two thermo elements P and N. A Peltier cooler allow the transfer of heat from one side of Peltier module to the other depending on the current's direction [18]. We can also use the Peltier cooler or thermoelectric cooler (TEC) as generator. If, we want to use the thermoelectric as cooler, we apply a voltage across the device and then we get that one side of the device is hot and the other side is cold. The performance of TEC depends on ambient temperature, design of the heat exchanger, Peltier parameters and geometry of Peltier module.
When we apply a voltage between two different conductors A and B, we will get a heat at the junction. The rate dq/dt of the generated heat is given as follow: