What are the types of compressors?

A compressor is a driven fluid machine that raises low-pressure gas to high pressure. It is the heart of the refrigeration system. It sucks low-temperature and low-pressure refrigerant gas from the suction pipe, compresses it by driving the piston through the motor, and discharges high-temperature and high-pressure refrigerant liquid to the exhaust pipe, providing power for the refrigeration cycle, thereby realizing the refrigeration cycle of compression → condensation → expansion → evaporation (heat absorption).

Compressors are divided into two categories: piston compressors and screw compressors.

Piston compressors are generally composed of a housing, an electric motor, a cylinder, a piston, a control device (starter and thermal protector) and a cooling system. There are two cooling methods: oil cooling and natural cooling.

The compressors of general household refrigerators and air conditioners use single-phase AC as power source, and their structural principles are basically the same. The refrigerants used in the two are different.

type

Compressors can be divided into volumetric compressors and speed-type compressors according to their principles. Volumetric compressors are further divided into reciprocating compressors and rotary compressors; speed-type compressors are further divided into axial-flow compressors and centrifugal compressors.

At present, household refrigerator and air conditioner compressors are all positive displacement, which can be divided into reciprocating and rotary types. Reciprocating compressors use piston, crank, connecting rod mechanism or piston, crank, sliding tube mechanism, and rotary compressors are mostly rolling rotor compressors. In commercial air conditioners, they are mostly centrifugal, scroll, and screw.

According to the application range, it can be divided into low back pressure type, medium back pressure type and high back pressure type. Low back pressure type (evaporation temperature -35-15 degrees Celsius) is generally used in household refrigerators, food freezers, etc. Medium back pressure type (evaporation temperature -20-0 degrees Celsius) is generally used in cold drink cabinets, milk refrigerators, etc. High back pressure type (evaporation temperature -5-15 degrees Celsius) is generally used in room air conditioners, dehumidifiers, heat pumps, etc.