Which kind of refrigeration system will be chosen for the construction of large cold storage will be more suitable?

　　The following is an analysis of several types of refrigeration systems suitable for large cold storage:

　　Compression refrigeration system:

　　Piston refrigeration compressor: suitable for small and medium-sized refrigeration occasions, in a large cold storage, if the demand for refrigeration is not particularly large, and cost control is more stringent, there will be a certain application. Its advantages are mature technology, relatively low price, easy maintenance. The disadvantage is that the efficiency is relatively low, running noise, more parts, maintenance workload.

　　Screw refrigeration compressor: currently more widely used in large-scale cold storage. It has the advantages of high efficiency and energy saving, large refrigeration capacity, stable operation, small vibration, low noise, etc., and can adapt to larger refrigeration capacity requirements and different working conditions. At the same time, the screw compressor has better adjustment performance, which can be flexibly adjusted according to the actual load change of the cold storage and reduce energy consumption. In addition, its structure is compact, covers an area of small, in favour of large-scale cold storage space layout.

　　Scroll-type refrigeration compressor: generally applicable to large-scale cold storage or as auxiliary refrigeration equipment with relatively small refrigeration capacity. Advantages are high efficiency, low noise, low vibration, smooth operation, and has a good volumetric efficiency and low leakage loss. Its structure is simple, few parts, high reliability and low maintenance cost. However, the refrigeration capacity of a single machine is limited, and it is usually necessary to use a number of parallel connection to meet the refrigeration demand of a large cold storage9.

　　Absorption refrigeration system: the use of refrigerant in solution absorption and release process to achieve refrigeration. Commonly used work mass pairs are ammonia and lithium bromine water solution. The advantages of this system are that it can utilise low-grade thermal energy, such as waste heat, waste heat, etc., and that it operates quietly, without vibration, and is friendly to the environment, and the refrigerant is usually water, ammonia, lithium bromide, etc., which is non-destructive to the ozone layer. The disadvantages are large equipment size, large floor space, high initial investment, high operation and maintenance costs, and relatively low refrigeration efficiency2.

　　Carbon dioxide and ammonia stacked refrigeration system: this is a more advanced refrigeration system, the country is now more respected use. It combines the advantages of carbon dioxide and ammonia two refrigerants, has the characteristics of safety and environmental protection, carbon dioxide belongs to the natural process, friendly to the environment, ammonia refrigeration efficiency. The system has superior performance at low temperatures and is capable of achieving lower evaporation temperatures, making it suitable for large-scale low-temperature cold storage. However, its technical threshold is high, the system is relatively complex, and the equipment investment cost is high1.

　　Liquid Nitrogen Refrigeration System: It absorbs heat through the evaporation of liquid nitrogen to achieve refrigeration. The advantages are fast refrigeration speed, which can make items reach extremely low temperature in a short time, precise temperature control, simple equipment and no pollution. However, the supply and storage cost of liquid nitrogen is high, and the operation cost is expensive. It is usually applied to special large-scale cold storage with extremely high temperature requirement, which needs to be frozen quickly and is not sensitive to the cost, such as some cold storage for biological products, high-end food freezer, etc2.

　　When choosing a refrigeration system for a large-scale cold storage, it is necessary to consider a number of factors, such as the purpose of the cold storage, the size, the budget, the operating cost, the environmental protection requirements, the safety and the local energy supply, etc. At the same time, it is recommended to work with a professional cold storage company. At the same time, it is recommended to have in-depth communication with professional cold storage construction companies or refrigeration technology experts to develop the most suitable refrigeration programme according to the specific situation.