In previous blog posts, we have discussed what dissolved solids are and what circumstances lead to their creation.  Last week, our blog dealt with "cycling up" water in a recirculating cooling tower system. As the water is "cycled up" and the mineral concentration increases, some of the minerals become so concentrated that they reach their saturation point and begin to come out of solution - that is, they start to "scale" out and can form extremely hard and insulating deposits on heat transfer surfaces. Because of this potential occurrence, a properly operated water treatment program should allow the water to be "cycled up" to a maximum number of cycles without forming the energy-robbing deposits. Your water treatment provider can look at your makeup water quality and water conditions in order to determine the maximum number of cycles that a specific recirculating cooling water system can safely operate at. An effective water treatment program should also control corrosion, maximizing your assets' useful life. In addition, special attention must be given to the microbiological control program as public health and safety must be the highest priority when operating these systems.

Makeup water quality is a major factor to be taken into account when determining maximum cycles of concentration for a cooling tower system. Other factors include:

• maximum temperature
• system metallurgy
• contaminant loading
• control capabilities

Once the maximum allowable cycles of concentration is determined, the goal would be to run as close to the maximum without going over. Remember, when you go over the maximum allowable cycles of concentration for a system, the chances of creating scale deposition on heat transfer surfaces is increased considerably.

How do you control and maintain the maximum number of cycles of concentration? Our blog next week will explain.