This project is based on thermoelectric peltier cooler. You can make instant ice cube with this little freezer. Thermoelectric cooling uses the Peltier effect to create a heat flux between the junction of two different types of materials.
A Peltier cooler, heater, or thermoelectric heat pump is a solid-state active heat pump which transfers heat from one side of the device to the other, with consumption of electrical energy, depending on the direction of the current.
The main application of the Peltier effect is cooling. However the Peltier effect can also be used for heating or control of temperature. In every case, a DC voltage is required.
While typically used for cooling, they can also be used for heating by reversing the electric current flow and even power generation.