Fitzer Closed Loop Cooling Tower operates in a manner similar to conventional cooling towers, except that the heat load to be rejected is transferred from the process fluid to water and ambient air directly through a heat exchange coil. The coil serves to isolate the process fluid from outside environment, keeping it clean and contamination free in a closed loop, thus creating two separate circuits

Primary / Internal circuit in which the process fluid circulates inside the coil

Secondary / External circuit sprays circulating water from the basin over the coil which evaporates to reject heat to the environment.