Cooling Tower
Evaporation Tracker
Audit condenser circulation rates and mineral concentrations to isolate precise blowdown thresholds and evaporation sags.
Open-Loop Condenser Thermodynamics, Cycles of Concentration, & Hydronic Mass Balance Physics Overview
Large water-cooled commercial chiller arrays drop vast structural heat gains into an open-loop condenser water framework terminating at an outdoor cooling tower asset. The core mechanism of heat rejection is fundamentally fluid-mass transfer: warm loop water entering the top distribution tree is broken into tiny spray droplets passing over internal fill media while a mechanical fan pulls cross-flow or counter-flow ambient air across the matrix. This forces a dedicated portion of the fluid volume to absorb its latent heat of vaporization and flash into pure steam vapor, stripping sensible temperature from the remaining liquid basin. However, when pure water evaporates, it leaves behind all dissolved solids, silica minerals, and calcium carbonates in the tower basin. This mineral build-up is measured as Cycles of Concentration (CoC). To stop these minerals from scaling up the internal copper tube surfaces inside the chiller shell, a controlled waste pipe stream, known as blowdown or bleed-off, must continuously discard hard water while fresh makeup municipal water replenishes the system.
Frequently Asked Questions
A: If the bleed loop shuts down while evaporation continues unabated, the cycles of concentration spike past safe saturation barriers. Dissolved calcium carbonate molecules immediately precipitate out of solution and form a stone-like mineral crust directly along the hot copper inner walls. Because calcium scale features a terribly high thermal insulation resistance rating, even a paper-thin scale layer blocks heat rejection, driving head pressures skyward and forcing high-amp chiller safety trips.
A: Rather than running an inefficient, constant mechanical drain line, modern plant manifolds embed precision electrical conductivity sensors straight into the basin water. Minerals dissolved in water directly expand its capacity to carry electrical current. When the basin’s micro-siemens index crosses factory setpoints (correlating to the maximum safe CoC scale boundary), the computer fires an automated motorized valve to bleed water, drawing down hard water mass until fresh municipal makeup water dilutes the basin index back to balanced design baselines.