The main component of the Medi-Freeze is the Peltier module, also known as thermoelectric module. Thermoelectric module or the Peltier module uses the Peltier effect to create a heat flux between the junction of two different types of materials. A Peltier module basically transfers heat from one side of the device to the other, that is it cools up one side and heats up the other, with consumption of electrical energy. Each Peltier tile consists of an array of alternating n- and p- type semiconductors.This Peltier tile is made using two thin ceramic substrates with a series of P and N doped bismuth-telluride semiconductors sandwiched between them. The ceramic material on both sides of the tile adds rigidity and the necessary electrical insulation. The N-type material has an excess of electrons, while the P type material has a deficiency of electrons. One P and one N make up a couple. The thermoelectric couples are connected electrically in series, and thermally in parallel, between the ceramics. On applying potential difference of maximum 12 volts across the Peltier tile, the electrons move from the P type material to the N type material through an electrical connector, the electrons jump to a higher energy state absorbing thermal energy (cold side), dropping to a lower energy state and releasing energy as heat to the heat sink (hot side). So, one of these ceramics will be the "hot-side" and the other, the “cold-side." The cold side is used to keep the medicines in the storage box at lower temperatures. The efficiency of the system depends on how well the heat is rejected out from the hot side of the Peltier tile.