Closed cooling towers, also known as closed cooling towers, (also called evaporative air coolers, closed cooling towers) place tubular heat exchangers in the tower to ensure cooling through the heat exchange of circulating air, spray water and circulating water. Because it is a closed cycle, it can ensure that the water quality is not polluted, which protects the efficient operation of the main equipment and improves the service life. When the outside temperature is low, the sprinkler system can be stopped to save water. With the implementation of the national energy conservation and emission reduction policy and the increasing scarcity of water resources, closed cooling towers have been widely used in metallurgy, aviation, electric power, chemical industry, machinery, petroleum, food, plastics, rubber and other industries in recent years.