The compressor is regarded as the heart of the refrigeration system, and the special term that can best show the characteristics of the compressor is called "steam pump". The actual responsibility of the compressor is to increase the pressure and raise the suction pressure state to the exhaust pressure state.
The compression ratio is a technical expression of the pressure difference, which means the absolute pressure on the high pressure side divided by the absolute pressure on the low pressure side. The compression ratio must be calculated using absolute pressure values. In order to avoid negative compression ratio calculations, absolute pressure rather than gauge pressure must be used to calculate the pressure ratio. It is meaningful to use the absolute pressure value to make the compression ratio calculation value positive.
There are five types of compressors used in the refrigeration and air conditioning industry: reciprocating, screw, rotary, scroll and centrifugal, of which reciprocating is the most used compressor in small and medium-sized commercial refrigeration systems. Screw compressors are mainly used in large commercial and industrial systems. Rotary compressors, scroll compressors are mainly used in household and small capacity commercial air conditioning units, centrifugal compressors are widely used in large building air conditioning systems.
Various reciprocating compressors are generally classified according to the form of the compressor housing and the setting of the drive mechanism. According to the form of the shell, there are open type and closed semi-closed compressor. Closed means that the entire compressor is arranged in a housing.