The compressor is one of the four fundamental components for the refrigeration cycle (compressor, condenser, expansion device and evaporator).
For the operation of the installation, there are three additional components: the component interconnection pipes, the refrigerant and the controls.
Other components are considered accessories and, if added in the system for the adequacy, safety and performance improvement and installation operation.
The function of the compressor is to raise the vapor pressure of the refrigerant to a pressure level such that it can be condensed.
Refrigerating compressors are divided into two main groups:
• positive displacement or volumetric compressors;
• centrifugal compressors or turbochargers;
The first group includes piston compressors (reciprocating or reciprocating), compressors with spindles (helical or screw type), or rotary compressors (blades). In industrial refrigeration the compressors are used mainly
piston reciprocators and screw type compressors, rotary compressors are rarely used (1st stage), with a low ratio of suction discharge pressures.
The second group belongs to centrifugal compressors. These are used in small-scale industrial refrigeration, but provide large flows of refrigerant vapor, usually applied to liquid-cooling plants in large facilities. The use of each type of compressor depends on the characteristics, operation, location, installation life, type of power (motor) available and other specific factors.
