Blow Down

As indicated, the water of evaporation exits the tower in a pure vapour state leaving behind its burden of total dissolved solids (TDS) to concentrate in the recalculating mass of water. Given no control, the TDS level in the circulating water will increase tremendously jeopardizing not only the cooling tower, but the heat exchanger and all other water circuit related components. The proper method for controlling TDS concentrations is called "blow down", where a portion of the circulating water flow (along with its TDS burden) is continuously wasted and replenished with relatively pure make-up water. Even if the assumed evaporation and drift rates were perfectly accurate, the calculated blow down rate might still not be quite enough because of the effects of the aforementioned airborne contaminants, which are usually incalculable. Once the approximate level of blow down has been determined, the circulating water quality is monitored and appropriate adjustments made. Despite the benefits of blow down, however, treatment of the water is often required to prevent scale formation, corrosion, or biological fouling/growth in the equipment and cooling tower sumps.

The use of EcoBeam XL eventually leads to cleaner water and lowered frequency of blow downs conserving water.