Home > The working principle of the compressor of the chiller
The working principle of the compressor of the chiller
Water chillers are also called ice water units, cooling units, refrigerating water units, or industrial chillers. It is a standard energy-saving refrigeration equipment. The refrigeration compressor is the core component of the entire chiller refrigeration system, and it is also the source of power for refrigerant compression. Its function is to convert the input electrical energy into mechanical energy and compress the refrigerant.
Refrigeration compressors can be divided into three types: open type, semi-closed type and fully enclosed type according to the sealing method. According to the working principle of refrigeration compressors, it can be divided into two categories: volume type and speed type, and volume type is divided into many types. Today we mainly come to understand the working principle of the reciprocating piston hermetic compressor.
The working process of the reciprocating piston compressor consists of four processes: suction-compression-expansion (work)-exhaust to form a cycle.
A Inhalation process: When the piston continues to move downwards and the gas pressure in the cylinder is lower than the pressure in the suction chamber, when the pressure difference is sufficient to open the suction valve, the inhalation process starts until the piston reaches the bottom dead center. end.
B Compression process: When the inhalation ends, the cylinder is filled with low pressure gas, the piston starts to move up from bottom dead center, the cylinder volume gradually decreases, the gas in the cylinder is compressed, and the pressure and temperature of the gas rise accordingly. . The suction valve is closed due to higher gas pressure, while the exhaust valve is therefore kept closed, the gas pressure has not yet reached the exhaust pressure, so the gas compression process will continue until the piston moves up until the gas pressure in the cylinder equals the exhaust pressure. When the pressure in the air chamber.
C Expansion process: When the piston starts to move downward from the top dead center, the cylinder volume gradually increases. Due to the existence of the clearance volume (mainly refers to the dead center gap and the exhaust hole volume below the exhaust valve plate), the high-temperature and high-pressure gas remaining in the clearance volume gradually expands, and the temperature and pressure of the gas also follow The expansion process will not end until the pressure in the cylinder reaches the pressure of the suction chamber. During the expansion process, the suction and exhaust valves are closed.
D Exhaust process: As the piston continues to move upward, when the gas pressure is slightly higher than the exhaust chamber pressure, the exhaust valve is opened (at this time, the gas force must overcome the mass of the valve plate and the spring force)
. The high-temperature and high-pressure gas in the cylinder is pushed out by the piston and enters the exhaust chamber. The exhaust process does not end until the piston moves to the top dead center.
To sum up, every time the piston reciprocates in the cylinder, that is, the crankshaft rotates once, the process of suction, compression, exhaust, and expansion must be carried out in sequence. The compressor runs continuously under the drive of the electric motor, and the piston continuously reciprocates in the cylinder, so the compressor repeats the above four processes to complete the gas compression and delivery work.
