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ECD installs an electrolytic cell in a side stream. A DC field drives scale-forming ions (calcium, magnesium, etc.) toward the cathode surface, where water reduction locally raises the pH to 9–11 and causes calcium carbonate to crystallise directly on the plate. The deposit is then removed mechanically or by automatic flushing. The difference is fundamental: chemical dosing keeps the scale-forming ions in the water by suppressing precipitation, which limits cycles of concentration to roughly 3–5; ECD physically removes the hardness ions from the water, decoupling scale control from the concentration ratio. The system can therefore run at higher cycles of concentration, reducing both makeup water and blowdown.

No. ECD is installed in a side-stream (bypass) configuration: a branch line is taken from the main circulating water pipe, passed through the electrolytic cell, and returned to the system. Tie-in work is carried out while the system is running, with no shutdown of the host equipment required.

Scale inhibitors can be reduced substantially or even stopped, but biocides, algaecides and pH adjusters are usually still needed. ECD addresses scale formation; microbiological control and corrosion control are separate problems. In practice, ECD should be regarded as a replacement for the scale inhibitor, not as a replacement for the entire water-treatment chemical programme.

Conventional chemical dosing typically operates at 3–5 cycles of concentration; beyond that range the inhibitor loses effectiveness and corrosion risk rises. ECD changes the limiting condition by physically removing hardness ions, but the achievable value still depends on the makeup-water quality, system metallurgy and blowdown strategy. The figure must be calculated from on-site water analysis and cannot be quoted without those inputs.

Savings come from the reduction in blowdown and makeup water as the cycles of concentration rise. As a worked example, a system with 2 million m³ of annual circulation running at 4 cycles under chemical treatment would have annual blowdown of roughly 100,000 m³. Switching to ECD can bring this down significantly, with annual water savings in the order of tens of thousands of cubic metres. The exact number depends on the makeup-water quality, target cycles of concentration and ambient temperature/humidity, and should be calculated against the specific site parameters.

Every 0.1 mm of scale raises the condensing temperature by approximately 1 °C and increases chiller power consumption by about 3%. For a 1,000 kW centrifugal chiller running 6,000 hours per year at an industrial tariff of ¥0.8/kWh, the annual electricity bill is around ¥4.8 million, so a 3% penalty is roughly ¥144,000 per year. Because the loss is invisible in day-to-day operation, it often persists for years.