Cooling Circuits & Cooling Water Conditioning

Types of water-cooling systems

• Direct Evaporative Coolers: These systems use water directly as a cooling medium. The water flows through the area to be cooled, absorbing and removing heat.
• Cooling Towers: In cooling towers, warm water is sprayed and passed through an air stream in a counterflow manner. A portion of the cooling water evaporates, releasing heat. Systems that involve water evaporation are known as open cooling systems.
• Indirect Evaporative Coolers: These systems have both an open and a closed circuit, separated by a heat exchanger. In the open part, water evaporates and releases heat. The cooled water is then passed through the heat exchanger, where it absorbs and removes more heat. The second circuit is closed, not directly exposed to the air, and does not lose water through evaporation. It transports heat from the heat source to the heat exchanger. Such cooling systems are often referred to as „semi-open.“
• Hybrid Coolers: Hybrid coolers utilize the closed circuit to cool only with cold air during cooler seasons. The open primary circuit is activated only when necessary.
• Adiabatic Coolers: These coolers use air as the cooling medium. Fine water mist is introduced into the air stream, which completely evaporates. This process removes heat from the air, which can then be used for cooling spaces or equipment.
• Mass Coolers: These coolers use a large water basin from which the cooling water is drawn, passed through the system to be cooled, and returned directly to the basin. The large water mass prevents significant temperature increases. Heat is released over the water surface of the basin.

Kühltürme oder Kühlanlagen unterscheiden sich jeweils durch das Prinzip, wie dem Kühlmedium Wärme entzogen wird

Beim Betrieb eines Kühlturms können verschiedene technische Probleme auftreten, die die Effizienz und Leistung des Kühlsystems beeinträchtigen

Cooling towers and cooling circuits: potential Issues

• Clogging: Pipes and nozzles in the cooling tower can become clogged due to mineral deposits or dirt, leading to reduced water flow and decreased cooling efficiency.
• Corrosion: Corrosion can affect both the metallic components of the cooling tower and the pipes and equipment of the cooling system. This reduces the system’s lifespan and cooling performance.
• Biofouling: Bacteria, algae, and other microorganisms can proliferate in the cooling tower and cooling system, forming biofilm layers. These layers impair cooling efficiency and contribute to corrosion.
• Pathogenic Growth: Cooling towers provide an ideal environment for the growth of Legionella and other pathogenic organisms. If these pathogens are dispersed into the environment via aerosols or air streams, they pose a health risk.

All these issues can be minimized through proper maintenance and conditioning of the cooling system. Common water treatment agents include biocides, corrosion inhibitors, dispersants, and hardness stabilizers.

Products for cooling water treatment

• Biocides: Used in cooling water treatment to control the growth of bacteria and other microorganisms, preventing biofilm formation that impairs cooling efficiency and contributes to corrosion. Modern biocides based on catalytically enhanced hydrogen peroxide, such as Sanosil C or Super 25, are highly effective. Hydrogen peroxide decomposes into water and oxygen, avoiding the formation of trihalomethanes.
• Corrosion Inhibitors: These are another crucial component of cooling water treatment. They protect the metallic components of the cooling system from corrosion and reduce the number of deposits in the cooling circuit. This results in a longer lifespan and higher energy efficiency of the system.
• Dispersants: Dispersants help prevent sediment formation from dust, scale, rust, and other contaminants by keeping the particles suspended in the water. These solids can then be more easily flushed out, maintaining cooling performance and reducing the need for cleaning. Dispersants also enhance the effectiveness of biocides.
• Hardness Stabilizers: Hardness stabilizers prevent the formation of scale deposits by stabilizing calcium and magnesium ions in the cooling water. This extends the system’s lifespan and improves energy efficiency.
• Pickling Agents: Used to remove flash rust or mineral deposits from cooling circuits, pickling agents allow poorly maintained cooling systems to be cleaned and put back into operation after maintenance.

Benefits of proper cooling water conditioning

The technical capabilities of cooling water treatment with biocides, corrosion inhibitors, dispersants, and hardness stabilizers provide a comprehensive solution to the challenges faced by cooling systems. The use of these products in cooling water treatment enhances the efficiency and performance of the systems, leading to significant cost savings. Additionally, modern cooling water treatment agents offer numerous benefits beyond improving system efficiency and performance.

Biofilm and Pathogen Control: The use of biocides reduces the growth of bacteria such as Pseudomonas, Legionella, and other harmful microorganisms. This stops health risks associated with bacteria-laden aerosols in the vicinity of the cooling tower.

Reduced Water Consumption: Another advantage of using cooling water treatment agents is the reduction in water consumption. By using dispersants and hardness stabilizers, an evaporative cooler can operate at an optimal concentration ratio of 3-4 times. This reduces the need for fresh water to replace the cooling water and extends the intervals between necessary cleanings of the cooling system.

In conclusion, the economic benefits of using biocides, corrosion inhibitors, dispersants, and hardness stabilizers in cooling water treatment are undeniable. These treatments not only improve system performance and efficiency but also provide essential health and environmental benefits.