FAQ

Thermal duty and design conditions (the real sizing drivers)
Heat rejection load, flow, entering/leaving water temperatures, and the site design wet-bulb drive tower size and fan power. Wet-bulb and “approach” heavily influence how big the tower must be.

Tower type and construction method
Open vs closed-circuit vs hybrid, and packaged vs field-erected/modular changes complexity, materials, and installation scope.

Materials and corrosion protection
FRP/galvanized/stainless options, coatings, fasteners, basin construction, and drift eliminator grades matter a lot in coastal/industrial environments.

Mechanical package and performance assurance
Fan system (direct/gear drive), motor/controls (VFDs), sound attenuation, and whether the product line is CTI certified for published thermal performance.

Site and installation scope
Rigging access, crane time, structural steel, piping/electrical runs, basin modifications, water treatment, blowdown handling, and compliance requirements (noise, drift, plume, chemical storage).

Cooling tower make-up water is consumed in four paths:

• Evaporation (the main one; it’s the cooling mechanism)

• Blowdown/bleed-off (water discharged to control dissolved solids)

• Drift (tiny droplets carried out with exhaust air)

• Leaks/overflow (avoidable losses)

 

Practical rule of thumb: about 1% of the circulating water is evaporated for every ~10°F (5.5°C) of cooling “range” (evaporation only; excludes blowdown and leaks).

Drift is typically very small versus evaporation and blowdown (often cited as ~0.01% or less of recirculating flow for modern eliminators), but it matters for nearby equipment and site constraints.

It can’t meet required leaving-water temperature under real design conditions
If your approach has degraded (you’re no longer getting close to wet-bulb at design load), you’ve effectively “lost capacity.”

Recurring unplanned downtime or major component failures
Fan/drive issues, chronic leaks, distribution problems, repeated basin or structural repairs.

Fill and internal components are physically degraded or fouled beyond practical recovery
Fill damage and blockage reduce heat transfer and airflow, often showing up as rising leaving-water temps and higher fan energy.

The tower no longer fits site needs or compliance expectations
Examples: noise limits, plume visibility, water restrictions, drift constraints, or a process change that requires a different type (e.g., closed-circuit).

Ambient wet-bulb temperature (dominant factor)
Wet-bulb sets the practical lower bound for leaving-water temperature; “approach” is leaving water minus wet-bulb.

Airflow quality at the inlet
Recirculation of hot, saturated discharge air back into the inlet (from poor placement, wind effects, nearby walls, or multiple towers) reduces performance because the tower “sees” a worse entering air condition.

Space, clearance, and maintenance access
You need room for unobstructed air entry, safe access to fans/fill/basins, and service/rigging. Obstructions can also raise fan power.

Water quality and local water constraints
Makeup-water chemistry influences scaling/corrosion risk, which feeds into blowdown needs and long-term reliability. Water availability and discharge rules can be design constraints.

Environmental constraints: noise, plume, drift, and sensitive nearby equipment
These can drive tower type (hybrid), sound packages, eliminator selection, and placement (setbacks, elevation, wind direction).