The refrigerator is one of the most important modern inventions. These devices are capable of preserving various foods and medicines fresh, preventing them from being damaged and allowing them to be used or stored for longer periods of time without spoiling or degrading.
The refrigerators are also used for scientific research, preserving samples of DNA, blood and all types of organic and inorganic material requiring low temperatures to avoid destruction.
The refrigerators are thermal machines that work under operating cycles based on thermodynamics. The operation of the cycle is simple, it involves flowing a refrigerant through various stages, in which it undergoes phase changes due to variations in pressure and temperature along the path of the refrigerant.
During these phase changes, heat exchange occurs between the refrigerant and the medium in which it is located. In this way, the refrigerant absorbs heat inside the refrigerator (cooling inside the appliance) and releases heat to the environment when it passes through the cooling system, which is usually located outside the appliance.
Refrigerators have four basic elements: compressor, condenser, expansion system and evaporator. In the following video, we will see how a refrigerator works: