Make Up Water In Cooling Tower [verified] -

| Parameter | Ideal Range | Why it matters | |-----------|-------------|----------------| | | 50–400 ppm (as CaCO₃) | Scale formation at high pH/temp | | Total alkalinity | < 400 ppm (as CaCO₃) | Decomposes to CO₂, lowers pH | | pH | 6.5–8.5 | Corrosion <6.5, scaling >8.5 | | Chlorides | < 500 ppm | Pitting corrosion (especially stainless steel) | | Silica | < 150 ppm | Hard, glass-like scale | | TSS | < 50 ppm | Fouling, sediment | | Iron | < 0.5 ppm | Staining, fouling | | Bacteria | No legionella or E. coli | Health risk (Legionnaires' disease) |

3. How to Calculate Make-Up Water Flow Step 1 – Evaporation (E) E (gpm) = Recirculation Rate (gpm) × Cooling Range (°F) × 0.001 Example: 1000 gpm system, 15°F range → E = 1000 × 15 × 0.001 = 15 gpm make up water in cooling tower

| Loss Type | Description | Typical % of Circulation | |-----------|-------------|--------------------------| | | The primary cooling mechanism. Pure water vapor escapes. | 1–2% per 10°F (5.5°C) range | | Drift (Windage) | Small droplets carried out by exhaust air. | 0.001–0.2% (modern drift eliminators) | | Blowdown (Draw-off) | Intentional bleed to control dissolved solids. | Varies (0.5–5% of circulation) | | Leaks/Overflow | System losses from seals, basins, or splashing. | Minimal if maintained | | Parameter | Ideal Range | Why it

Assume 0.01% of circulation for well-maintained towers: D = 1000 × 0.0001 = 0.1 gpm Pure water vapor escapes