Cooling towers and condenser water: what goes wrong
A water-cooled chiller is only as good as the loop behind it, and that loop needs attention the chiller does not.
When a water-cooled chiller starts losing efficiency, the cause is more often in the condenser water circuit than in the machine. The tower is where evaporation concentrates everything the water carries.
Scale
Evaporation removes water and leaves dissolved solids behind, concentrating them every cycle. Left unmanaged, scale forms on the condenser tubes. A thin layer is enough to raise condensing temperature measurably, and it shows up as a rising condenser approach long before anything else.
Fouling and biological growth
A tower is an efficient air scrubber, which means it collects dust and organic matter and holds them in warm water. That produces biofilm, which insulates surfaces and accelerates corrosion. It is also a health matter: warm aerosolised water demands proper treatment and monitoring, not occasional attention.
Corrosion
Oxygenated, warm, circulating water attacks metal. Treatment chemistry is the control, and it needs to be dosed and verified rather than assumed.
What proper management looks like
- Water treatment with a regime and a testing record, not just a dosing pump
- Bleed and make-up set so the cycles of concentration stay within limits
- Fill, drift eliminators and basin inspected and cleaned on a schedule
- Strainers checked; basin kept free of debris
- Condenser approach trended, because it is the clearest evidence of tube condition
The connection back to the chiller
Every degree the condenser water is warmer than it should be raises condensing temperature and costs compressor power. Tower maintenance is chiller efficiency work, even though it happens at the other end of the loop.