A mechanical-draft cooling tower uses a fan to move air through a heat-rejection process in which evaporation removes heat from water. Its selection depends on the entering and leaving water temperatures, water flow and outdoor wet-bulb condition. Nominal tower tonnage alone is not a reliable basis for comparing offers.
Separate range from approach
The range is the difference between hot water entering and cooled water leaving. The approach is the difference between leaving water temperature and entering-air wet-bulb temperature. A smaller approach can require a more demanding tower selection.
Ask all suppliers to use the same design point. SPX's cooling-tower thermal guidance explains the difference between range and approach. The quotation should include a performance selection for the project's water duty and air conditions.
Air and water both need a clear path
Locate the tower to limit recirculation of warm moist discharge air into the intake. Screens, walls and neighbouring units can affect the air path. Coordinate water distribution, pump duty and basin operation rather than treating the tower as an isolated box.
Crossflow and counterflow arrangements differ in air-water movement, layout and access. Compare the installed arrangement, including maintenance around fill, eliminators, fans and distribution components.
Plan water management from the start
Evaporation concentrates dissolved material. Makeup water, bleed control and treatment must suit the water analysis and operating conditions. The water-management programme also needs to address microbial risks and periods of shutdown.
CDC guidance for cooling towers identifies them as systems requiring active Legionella control. Drift eliminators are a component of the design, not a substitute for water management and maintenance.
Include access for cleaning the basin and replacing service parts, plus the method for isolating a cell where relevant. Water, fan energy, treatment and maintenance belong in the lifecycle comparison.
Send the heat-rejection duty, water flow and site conditions to shengtongJH for configuration and sourcing coordination.