how refrigerators work

 

Disconnect the refrigerator from power, then disconnect the line that carries chilled water into the refrigerator. Now you can see all of the components inside and how they work."

A fridge is a large machine that stores food in an environment with cold temperature. There are many types of refrigerators: chest type (referred to as "door-type") and upright type (referred to as "bottom-type"). The most common one is Upright or Bottom-Type Refrigerator which come in two different configurations, 1.1 cu ft & 3.3 cu ft capacity, which is often called a domestic refrigerator or a fridge for short. A domestic refrigerator, conversely, is a small version of an industrial-scale refrigerator.

 

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The most common type of refrigerator uses a combination of vapor compression and liquid cooling. Generally speaking, the compressor is not integrated into the evaporator (a heat exchanger system) but instead it is located in its own separate unit below the evaporator compartment. It is driven by either an electric motor (common on single-door units), a gas engine driven compressor or an air conditioner with refrigerate-air bypass. The compressor draws in cold outside air and pushes it through a small metal hose into the evaporator compartment, where the cold air condenses into water vapor at low pressure.

The vaporized water is collected in the condenser part and goes back to the compressor with a small amount of refrigerant. The hot condensing gas is vented to the outside of the refrigerator. The cycle then starts again.

 

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There are two ways in which a refrigerator can achieve cooling: open cycle or closed cycle. In open-cycle systems, which are typically used in household refrigerators, air is blown across an evaporator coil containing water; this causes evaporation and hence cooling as at any other evaporator/condenser heat exchanger when driven by a compressor (a compression refrigerator). However, the system is open and a cooling effect is achieved only when air is blown across the coil.

In a closed-cycle system, water circulates in pipes through the refrigerator's cold box. Air passes over these pipes and condenses on the cooler pipe walls and returns to the compressor as described above. The difference between an open cycle and a closed cycle refrigerator is that in an open-cycle system cold air from outside the refrigerator strikes directly on the evaporator coil containing water; whereas in a closed-cycle system, cold air from inside or outside of the refrigerator does not directly strike on to an evaporator coil containing water. The refrigerant flow in the evaporator compartment will be sufficient to cool the main liquid phase at a temperature over the boiling point, but not to raise the liquid phase temperature to below 100°F (50° C).

The most important part of a refrigerator is the evaporator unit. It consists of most of an automobile refrigerant cooling system. An important part of this cooling system is a fan which moves air through the evaporator and draws in fresh outside air from which water vapor is drawn into the condenser, then back into the evaporator. The air used for cooling is at a lower pressure than that outside and passes through a small hose into an evaporation pan containing water.