How does water quality affect closed cooling towers?
2021-07-23
Closed-loop cooling towers require high water quality standards. Whether it's a closed-loop or an open-loop cooling tower, water must be continuously recycled. But how exactly does water quality affect the performance and longevity of both closed-loop and open-loop cooling towers?
When operating with a closed cooling tower, impurities in the water circulate along with the water flow to various components—such as pumps, packing materials, condensers, spray systems, and circulation pipes—leading to potential performance issues.
In closed cooling towers, water quality has a much more significant impact compared to open cooling towers. In contrast, the circulation in open cooling towers is straightforward: all the spray water is pumped and routed through pipes back to the reservoir after being sprayed.
In this process, the water spray in a closed cooling tower is tailored to each specific application. When used in certain industries, it must be equipped with a heat exchanger. Consequently, the quality of the water directly affects the inner walls of the heat exchanger as well. Meanwhile, the closed cooling tower separates the internal and external circulation systems—allowing the external circuit to rely solely on water spray, which circulates only through the outer wall of the condenser.
How does the water quality of a closed cooling tower affect the overall quality of the cooling tower?
1. Scaling occurs in both open and closed cooling towers, though the nature of the buildup differs slightly. In open cooling towers, scale primarily forms on the packing material, while in closed cooling towers, it tends to accumulate mainly on the outer walls of the condenser—and some of it may even continue to adhere to the inner walls of the tower itself.
2. The packing material becomes damaged—after operation, the scale formed in closed cooling towers typically adheres to the surface of the packing. Made from a high-quality plastic layer, this packing is relatively durable; however, over time, the accumulated scale can become quite heavy. If left unchecked, this buildup may eventually lead to tearing or damage of the packing, disrupting normal operation and necessitating replacement when needed.
3. Impact on Heat Pipe Cooling Performance: After use, the cooling tower develops scale that adheres to the packing material and even coats the surface of the condenser, thereby hindering the heat pipe's effective heat dissipation and reducing natural ventilation efficiency. Circulating air relies specifically on the gaps between the packing and condenser to facilitate heat transfer. However, the buildup of scale occupies part of these spaces, leading to diminished airflow. Additionally, the scale directly compromises the performance of both the packing and the condenser’s heat pipes.
4. The nozzles are clogged. Their primary function is to atomize and evenly spray water. However, impurities can block the nozzles, resulting in uneven mist distribution within the space—leading to partially dry spots or areas where the packing material dries out. This condition could potentially cause the cooling tower to catch fire under high-temperature conditions.
5. The water pump is damaged. The pump serves as the dedicated power system for spraying water, but if impurities are drawn into it, they can cause blockages. Although the pump is equipped with a filter, there’s still a risk that the filter itself may fail—or worse, mud passing through the filter could lead to insufficient circulating water flow, overheating, and reduced pump performance.
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2025-09-17