A Cooling tower is a heat rejection device, which works to cool water stream to a lower temperature ultimately emitting waste heat into the atmosphere. An evaporative technique is used in which a small water portion is cooled and evaporated into an air stream and subsequently discharged thereby cooling the rest of the water stream significantly. They are more cost and energy efficient than dry heat rejection devices like a car radiator and hence more widely used in large cooling applications.
Air conditioning systems, electric power generation units and manufacturing establishments typically employ cooling towers for providing cooled water to run equipment.
The major issues associated with cooling tower treatment and water treatment include:
Cooling water systems are an ideal environment for the metal to reverse to its the original oxide state. This process of reversal is referred to as, corrosion.
Minerals such as calcium carbonate, calcium phosphate, and magnesium silicate form scale deposits when exposed to conditions commonly found in cooling water systems.
The deposition of suspended material in heat exchange equipment is called fouling.
Cooling water systems provide an ideal environment for microbial organisms to grow & multiply.
Each of these conditions have their own share of problems.
Additionally they cause:
- Increased maintenance cost
- Frequent shutdowns
- Increased energy consumption & fuel costs
It is imperative to understand the nature & type of cooling tower to be able to provide the best water treatment solution tailored to the needs.
Depending on the cooling tower & the water characteristic, a chemical or mechanical process may be employed to treat water. In the chemical method, a range of corrosion and scale inhibitors are selected to match the water chemistry, system metallurgy and operating conditions in order to provide maximum protection. Sulfuric, Hydrochloric, or Ascorbic acid, when added to recirculating water, can improve the efficiency of a cooling system by controlling the scale buildup . Acid treatment lowers the pH of the water and hence prevents scale formation.
The mechanical method involves using a variety strainers, filters, and centrifugal separators. Physical removal of particulate matter ensures the microbial activity is reduced.
Monitoring is an important aspect of any water treatment program. Through proper and continuous monitoring, the effectiveness of the programme can be determined. Also it will help determine the optimum level of treatment.
Monitoring largely serves two basic purposes:
- To continuously check the condition of the operational equipment
- To relate the condition to variables such as PH level, water quality etc
Cooling tower treatment is important, it’s recommended you apply preventative maintenance.