Chiller Makeup Water

Cycles of concentration measures how many times minerals have been concentrated relative to the makeup water supply. Poor-quality makeup water with high TDS forces operators to blowdown frequently at 2-3 COC, wasting significant water. Treating makeup water with RO to reduce TDS below 50 ppm commonly allows systems to run at 6-8 COC, cutting water consumption by 30-40%.

For most commercial cooling towers, makeup water TDS below 200 ppm allows operation at 5-6 COC without aggressive chemical treatment. At that concentration level, the system blowdown TDS stays under 1,200 ppm, which is manageable with standard corrosion inhibitors. AMPAC USA chiller makeup systems typically target 50-150 ppm product TDS depending on your tower design and local discharge limits.

Yes, significantly. Lower makeup water TDS means less scale-forming calcium and magnesium entering the system, which reduces the required dose of scale inhibitors and biocides. Many facilities cut chemical spend by 40-60% after installing RO makeup treatment. The capital cost of an RO system often pays back within 18-24 months through chemical and water savings combined.

System capacity depends on tower volume, evaporation rate, and target COC. A 500-ton cooling tower typically evaporates 75-100 GPH, and running at 6 COC requires only 15-17 GPH of RO product continuously. Most installations use a small-capacity RO with a product tank sized to handle overnight makeup demand without running the system continuously.

Nutrient-rich makeup water with high organic loading creates conditions where Legionella bacteria thrive in biofilm on tower fill and basin surfaces. RO-treated makeup water reduces the organic load entering the system, making it harder for biofilm to establish. This does not replace a proper biocide program, but lower nutrient levels mean biocide dosing is more effective and required less frequently.