There are four categories of low-temperature series, namely air-cooled box type, water-cooled box type, air-cooled screw type, and water-cooled screw type. The outlet temperature of the refrigerant is adjustable from -40℃ to -85℃, and the cooling capacity of the single machine is 1KW to 300KW for selection. The flow rate of the refrigerant is determined according to the working condition and the cooling capacity. The product is completed in the factory, after testing various indicators, filled with refrigerant, and then through water and power to start commissioning, to ensure that all parameters are qualified before leaving the factory.