Refrigeration compressor, as the "heart" of the refrigeration system, plays a key role in compressing low-temperature and low-pressure gaseous refrigerant into high-temperature and high-pressure gas, thereby ensuring the smooth progress of the refrigeration cycle.

I-Main classification of refrigeration compressors

According to the working principle, refrigeration compressors are mainly divided into two categories: volumetric compressors and speed compressors.

1. Positive displacement compressor

Positive displacement compressors compress gas by changing the cylinder volume. This type of compressor can be divided into reciprocating compressor and rotary compressor.

1) Reciprocating compressor: Piston compressor is the most widely used type of reciprocating compressor. Its working principle is to complete the gas compression process by continuously changing the working volume composed of the cylinder, the air valve and the piston that reciprocates in the cylinder. Piston compressors are widely used in medium and small refrigerators, and their cooling capacity ranges from 60 to 600kW. According to structural characteristics, piston compressors can be divided into open, semi-hermetic and fully hermetic.

2) Rotary compressor: Rotary compressors include rolling rotor compressors and scroll compressors. The rolling rotor compressor has a simple structure, small size and light weight. Compared with the piston compressor, the volume and weight can be reduced by 40% to 50%. It is widely used in household air conditioners or small refrigeration equipment. The scroll compressor is the third generation compressor. Its multiple compression chambers work at the same time. It has high volumetric efficiency, up to 98%, reliable operation and low noise. It is mainly used in air conditioning, heat pumps, refrigeration and refrigeration and other fields.

2. Speed compressor

Speed compressors rely on the kinetic energy and speed changes of gas to compress. This type of compressor mainly includes axial flow compressor, centrifugal compressor and mixed flow compressor. Centrifugal compressors are widely used in large-scale refrigeration systems. Their compression process is continuous and adaptable to variable speed motion and variable frequency speed regulation technology.

II- Other classification methods of refrigeration compressors

In addition to classification by working principle, refrigeration compressors can also be classified in other ways.

1) Classification according to evaporation temperature range: it can be divided into high temperature, medium and low temperature compressors. This classification is primarily based on the operating conditions of the compressor and the type of refrigerant required.

2) Classification according to sealing structure: it can be divided into open compressor and closed compressor. Open compressors are easy to maintain, but have poor sealing properties; closed compressors have better sealing properties, but are relatively difficult to maintain.

III-Characteristics and applications of various types of refrigeration compressors

1) Piston compressor: It has the advantages of simple structure, easy manufacturing, and convenient maintenance, but it has the disadvantage of large vibration and noise. Suitable for medium and small refrigeration systems.

2) Rotor compressor: small in size, light in weight and high in efficiency, it is widely used in household air conditioners and small refrigeration equipment.

3) Scroll compressor: high volumetric efficiency, low noise, reliable operation, especially suitable for frequency conversion speed regulation technology, and is an ideal choice for air conditioners, heat pumps and other fields.

3) Centrifugal compressor: suitable for large-scale refrigeration systems. The compression process is continuous, but the structure is complex and the cost is high.

IV- Maintenance and maintenance of refrigeration compressors

No matter what type of refrigeration compressor, inspection and maintenance work is required to ensure its long-term stable operation. This includes regular cleaning, checking oil levels, changing lubricants, checking electrical systems, etc.

V- Conclusion

As the core component of the refrigeration system, refrigeration compressors are classified into various categories and each has its own characteristics. Understanding the performance and characteristics of different compressors will help us choose the appropriate compressor type according to actual needs, thereby improving the efficiency and reliability of the refrigeration system.