Chillers are also known as cooling equipment. Because they are widely used in all walks of life, the requirements for chillers are not the same. Its working principle is a multifunctional machine that removes liquid vapor through compression or heat absorption refrigeration cycle. In the refrigeration industry, it can be divided into air-cooled chiller and water-cooled chiller. According to the compressor, it can be divided into screw chiller, scroll chiller and centrifugal chiller. In terms of temperature control, it is divided into low-temperature industrial chiller and normal temperature chiller. The temperature of normal temperature chiller is generally controlled in the range of 0-35 ℃. The temperature of low temperature unit is generally controlled from 0 ℃ to - 100 ℃.