Freezers help preserve food by removing the heat from the inside of the appliance. In a similar manner to a fridge, a freezer uses the process of evaporation to keep food fresh. All freezers feature a compressor, which is a pump that compresses refrigerant in gas form. Following this, the gas is condensed into a hot liquid. Once the refrigerant has passed through the condenser coils, it travels to the evaporator coils cooling compartment, where it expands into a gas, making the coils cold in the process. Finally, the gas flows back to the compressor where it is converted into a liquid as the cycle continues.