What Does Conductivity Tell You About a Cooling Tower?
Why is conductivity the single most critical parameter continuously monitored in cooling tower loops?
How electrical conductivity serves as the real-time operational proxy for dissolved solids, cycles of concentration, and blowdown automation.
Technical Engineering Analysis
Electrical conductivity (measured in microSiemens per centimeter, μS/cm) reflects the total concentration of dissolved ionic minerals (Ca2+, Mg2+, Na+, Cl-, SO4(2-)) carrying electric current through water.
Because evaporative cooling removes pure H2O, ionic concentration rises continuously. Conductivity provides a dependable, instantaneous linear proxy for Total Dissolved Solids (TDS ≈ Conductivity × 0.65 to 0.75).
Automated controllers like the Walchem W900 compare tower conductivity against programmed setpoints. When conductivity reaches the target limit, the controller actuates a blowdown valve to purge high-mineral water while introducing fresh make-up.
Toroidal (electrodeless) conductivity sensors are mandatory in industrial cooling loops because traditional contacting electrodes rapidly foul with oil, biological slime, or mineral deposits, causing false low readings that prevent blowdown.
Engineering Diagnostic Checklist:
If conductivity spikes rapidly despite continuous blowdown or if your system suffers from sensor fouling drift, consult C-Water for toroidal sensor retrofits and blowdown valve sizing.
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