Closed cooling tower is a deformation and development of traditional cooling tower. It is actually a combination of an evaporative cooling tower, a cooler, and a wet cooling tower. It is a horizontal evaporative cooling tower in which process fluid flows inside the pipe and air flows outside the pipe, without contacting each other. The water in the tower bottom reservoir is pumped by a circulating pump and sent outside the pipe for uniform spraying. It is not in contact with process fluid hot water or refrigerant and air outside the pipe, forming a closed cooling tower that enhances heat and mass transfer through spraying water.