The refrigeration cycle works to reduce the temperature in the refrigerator and control it to a constant temperature. Often homes have a common refrigerator, separate in a shop or factory. To keep food in the fridge longer, its temperature should be from 0 ° to 4 ° C. Talking about the main parts, the mechanical compression system works in domestic refrigerators. The heart of the refrigerator is its compressor. It is always at the bottom, behind the fridge. The condenser is a type of lattice behind the fridge. The refrigerant cools the condenser to steam and makes it into a liquid state. Expansion valve in the refrigerator lowers the temperature of the refrigerant. The evaporator works by absorbing heat from the outside and steaming the liquid refrigerant. Apart from this, dryer is also important in the functioning of the refrigerator. In 1915 Alfred Milose built the first self-contained electric refrigerator.