What are the common problems in cooling tower?

Algae Bloom & Bacteria Growth

Algae bloom in the cooling tower water promoted the growth of bacteria and increase the risk of Legionella. Overly grown algae flow into the pumps and chiller’s tube might causes huge operational inefficiency.

White Rust, Corrosion &
Chemical Pollution to Rivers

White Rust is a type of corrosion that affects galvanized steel, often caused by high pH levels and excess carbonate ions in the water. Meanwhile chlorides and sulfates can accelerate the corrosion process if their concentrations are not properly controlled.

Water pollution cause by heavy chemicals usage in the cooling tower water, which typically being released into the environment through cooling water blown-down (either to reduce Total Dissolved Solids TDS level in the water, or during cooling tower washing)

Scaling in Cooling Equipment &
Energy Wastage

Scale, Slime and Biofilm formed in the chiller’s water tubes cause inefficiency in heat-transfer process. Condensation of refrigerant is much slower, causing chiller’s compressor to consume more electricity. Scale formation cause the water pressure drop through the pipes and reduce the heat-release efficiency of cooling tower fills.

What is Scale?

Scale is the hard-minerals deposit that is formed within the inner surface of water flow piping, cooling towers, chillers, boilers, heat exchangers evaporative condensers etc.

Calcium Carbonate and Magnesium Carbonate are usually the main component of scales formation in the water systems.

Chiller’s Energy Wastage due to Scale Deposit

Scale deposit causes a great wastage of energy resulting from the lower heat transfer / thermal conductivity inefficiency. Typically, a calcium carbonate scale of just 0.5mm in thickness is estimated to Energy Wastage by 18% .

Thermal Conductivity of Watts per meter Kelvin (W/m K)
Copper 393
Aluminium 221
Iron 67
Mineral Scales 0.08 ~ 3.2
Calcium Carbonate 2.9
Biofile (microbial film) 0.41 ~ 0.95

Factors Contributing to Scales Formation

High pH – Increase in pH and alkalinity values reduce the solubility of calcium carbonate and other minerals in the water.

High TDS – The rise of Total Dissolved Solids (TDS) increase the rate of scale formation as water evaporates.

Temperature – Temperature elevation causes carbon dioxide to evaporate and allows scales to form.

Water quality – Microbial growth and the presence of suspended solids found in water increase scales and cause deposition formation, as they act as nucleation sites for crystallites seeding. Slime formed by bacteria acts as a binder for scales and other foulants as well.

DéScale Application & Benefits

Cooling Tower and Piping

Scale removal of cooling tower infills, pumps and piping system. Disinfecting algae, biofilm and microorganism in the cooling tower water system. Improving performance of the whole cooling system.

Chiller and HVAC

Effective removal of scale deposit in heat-exchanger tubes of the condenser (open-loop) and evaporator (close-loop). Energy savings resulting from improved heat transfer co-efficiency.

Boiler

Removal of scale from boiler fire tubes (surface which comes in contact with water), condensation tanks, piping and pumps. Fuel savings resulting from improved heat transfer co-efficiency.

Evaporative Condenser

By removing scale deposits on evaporative condenser tubes, heat transfer/cooling efficiency will improve tremendously. Cleaning of the tubes becomes much easier as hard scale turns into soft, muddy substance over time.

Heat-exchanger/Oil Cooler and Injection Molding

The ability to transfer heat remains a central feature for many industrial processes. Malfunctions in heat transfer caused by hard scale could result in reduced production output, increased rejection rate and reworks. For instance, inefficiency in the heating and cooling processes in plastic injection moulding machines often result in deformation of end-products. Constant scale removal and prevention on a sustainable basis is crucial.