This paper reviews the design and installation associated with three large cooling towers with capacities from 4,000 tons to 10,000 tons. These installations are connected with a hospital, a university, and a convention center and have operational durations of 2 to 3 seasonal cycles. These design concepts give great flexibility and can be implemented in industrial applications of 100,000 GPM for most scale control requirements. The design of these PWT systems, its installation, and their results will be delineated. Data on COC, conductivity, pH, with the resulting biological, corrosion and scale control results presented.