The process fluid is circulated through the coil of closed circuit cooler. Heat from the process is dissipated through the coil tubes to the water cascading over the tubes exchanger. Simultaneously, air is forced upward, over the coil opposite the water flow by the fans (axial or centrifugal). A portion of the water is evaporated which removes the heat. The warm moist air is discharged to the atmosphere while the cooled water drains to the basin at the bottom of the cooler where it is recirculated by the electrical pump up through the distribution system of the water from more nozzles, and back down over the coils.
Wet bulb calculation