There are many types of compressors used in the commercial refrigeration field, mainly including hermetic piston compressors, semi-hermetic piston compressors, scroll compressors and screw compressors. In terms of quantity, hermetic piston compressors have the largest number, followed by semi-hermetic piston and scroll compressors with similar sales volume, and screw compressors with the least number. According to statistics, in the next few years, the annual growth rate of my country's commercial compressor industry will be about 11%, and large-scale and centralization have become prominent features, so the small number of semi-hermetic screw compressors will become one of the biggest highlights. 1. The role of cold chain logistics is obvious In recent years, my country's economy has entered a stable development track. According to many experts in the industry, adjustment and transformation have become an inevitable trend, and demand structure adjustment is a long-term strategy. Demand structure includes internal and external demand structure, consumption and investment structure in domestic demand. my country's economic growth is mainly driven by the joint action of investment, consumption and export trade, which is called the "troika". Among the "troika", the most stable, most efficient and most sustainable driving force is the consumption of domestic residents. Residents' consumption includes food, clothing, housing, and transportation. Overall, "eating" has become one of the main factors driving consumption. However, compared with developed countries, in terms of food, my country's cold chain logistics hardware transportation equipment and infrastructure are seriously insufficient, and the original facilities are outdated and unevenly distributed, which cannot provide temperature guarantee for cold chain transportation of food circulation. The demand for establishing and improving cold chain infrastructure is becoming unprecedentedly huge, especially the promulgation of the "Agricultural Cold Chain Logistics Development Plan", which clarifies the development direction and determination in the next few years. Further improvement and strong policy support; at the same time, with the process of urbanization and the continuous improvement of living standards, the demand for cold storage in the market, whether it is small, medium or large, is steadily increasing. The country has issued a development plan for the cold chain logistics of agricultural products, and the investment in the food cold chain industry has triggered a new round of rapid rise in the demand for cold chain equipment. Among them, cold storage is a key link in the food cold chain. A number of equipment factory leaders predicted to reporters that the refrigeration industry will have at least five years of good days. 2. Large-scale projects to meet development Nowadays, the construction of cold storage in my country shows several notable characteristics: one is the increase in quantity; And the direction of automatic, flexible and diverse, efficient and safe, environmental protection and energy saving in the loading and unloading of goods in and out of the warehouse. This trend just caters to the use of semi-hermetic screw compressors. It is understood that the biggest advantage of the screw compressor is the large cooling capacity, which is suitable for low temperature cold storage. The characteristics of less wearing parts, long maintenance period, high volumetric efficiency, low exhaust temperature, insensitivity to liquid hammer and stepless adjustment of cooling capacity make screw refrigeration compressors more and more appreciated by users; At the same time, it is also widely used in various sectors of the national economy where artificial refrigeration is required, such as the production of petroleum, chemical, light industry, medicine and other industrial products, low-temperature experiments in scientific research, low-temperature processing, storage and public places of food and aquatic products. Air conditioning in large buildings, etc. 3. Renovation of ammonia machine system shows its skill. Some time ago, a major accident occurred in the main plant of Jilin Baoyuanfeng Company, resulting in heavy casualties and property losses, causing great shock to the society and causing violent turmoil in the cold chain and warehousing industry. Preliminary investigations showed that due to the short circuit of some electrical lines, the surrounding combustibles were ignited, and the high temperature generated by the combustion caused the physical explosion of the ammonia equipment and ammonia pipeline. This is also enough to sound the alarm again for refrigeration practitioners. Therefore, from the beginning of June to the end of September, the government, in the name of the State Council Safety Committee, organized a centralized inspection of production safety for enterprises in all regions and industries across the country and strengthened the supervision of the whole process. Effectively eliminate hidden dangers through comprehensive coverage. Among the many refrigerants, ammonia is a refrigerant with distinctive characteristics, which is the most widely used in large-scale refrigeration systems around the world, and the same is true in my country. With the expansion of urbanization, the original suburbs have become urban areas, and the ammonia system equipment built in the surrounding area cannot meet the market demand, and is not suitable for local development. Influenced by manpower, management, technology, etc., the renovation of old-type ammonia machine cold storage has risen, and screw compressors have shown their talents.