As an important subsystem in the normal operation of industry, "circulating water" plays a key role in the sustainable, efficient and economic operation of industrial production.

Industrial water consumption accounts for about 20% of the total water consumption in China, and most of the total industrial water consumption is for industrial cooling water. Therefore, the progress of industrial water cooling technology directly determines environmental, safe and efficient performance of national economy, in which the core device of its cooling system is closed cooling tower.

Classification of circulating water cooling technology: closed cooling tower (countercurrent type, francis turbine type), air-cooled heat exchanger (induced-draft type, forced-draught type), composite closed cooling tower, intelligent water-saving closed cooling tower.