All refrigerators consist basically of the same components: compressor, condenser, filter drier, capillary tube and evaporator. What can vary are the dimensions of each system, according to the capacity of the refrigerator. However, there is a differentiation in the configuration of each refrigeration system, which basically are three:
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Manual defrost (Touch defrost)
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Cyclic or semi-automatic defrost (Cycle defrost)
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Frost free
Manual defrost
(Touch defrost)
The refrigeration system in most small products (including freezers) uses a single evaporator, in which the defrosting is done manually. The evaporator is also used as a freezer in these products.
Air circulation in the freezer and the rest of the cabinet occurs by natural convection. As the warmer air rises and the colder descends, heat is withdrawn from inside the refrigerator.
Semi-automatic defrosting
(Cycle defrost)
In some medium capacity refrigerators, we find two evaporators connected in series and that remove heat from the upper and lower compartments independently.
The defrost in the freezer must be done manually, and in the refrigerator compartment it is done automatically, every cycle of the compressor.
The small ice formations in the refrigerator compartment melt during this cycle and follow through a chute out of the refrigerator where it evaporates.
To assist in the evaporation of this liquid, an extension of the condenser (to emit heat) is often used, close to the compressor.
Automatic defrost
(Frost free)
In this system, used in larger and more sophisticated refrigerators, there is a single evaporator whose defrosting is done automatically at scheduled intervals.
The evaporator is located in the
Freezer compartment, but without direct contact. In these products, the circulation of air through the compartments of the freezer and refrigerator is made by a fan.
Most frost-free products have two condensers: the main one works with a fan, and the secondary one helps to warm up the suds and evaporate the water from the defrost.
The defrost of the evaporator is made by a resistor that operates in the cycle intervals of the compressor.
