After examining what it means to "cycle up" water in a recirculating cooling tower system
, last week our blog dealt with the system's Cycles of Concentration
. Your water treatment specialist can help you determine what the maximum number of cycles is for your system. Once that is determined, the best method for maintaining this maximum number of cycles is an automatic control system that controls the tower water to a predetermined level of total dissolved solids. Conductivity is an easy measurement that correlates well to total dissolved solids. As the level of total dissolved solids cycles up through evaporation, an automatic conductivity controller can energize a blowdown valve based on a conductivity set point. This allows highly concentrated recirculating cooling water to be sent to the drain. As low conductivity make up water refills the system, it dilutes out the recirculating water and maintains the cycles of concentration at a preset level.
A cooling tower allows the user to reuse, recycle and reduce water consumption. As a result, cycles of concentration play a big part in minimizing water usage and maximizing water conservation for these systems. The higher the cycles of concentration, the less water that is lost from the system in the form of blowdown. Small increases in the cycles of concentration can mean huge savings in:
- daily makeup water
- bleed water volumes
- associated water costs
- chemical treatment costs
To site an example:
A 5000 gpm recirculating cooling water system with a 10 degree F water temperature drop through the tower is operating at 3 cycles of concentration but could safely operate at 4 cycles. That tower would use 3,000,000 gallons of fresh makeup water more than necessary in a year's time if operating 24/7, 350 days a year. Correspondingly, the bleed volume would increase by the same amount. Based on today's ever-increasing water and sewer costs, that could amount to significant and unnecessary operating cost expenditure, not to mention using more of our precious water resource than necessary.