When it comes to evaporative condensers, the first thing that comes to mind is their significant energy-saving advantage—especially the prominent power-saving effect. Unlike traditional atmospheric condensers that require large amounts of water to be transported over long distances, evaporative condensers rely on their own small-cycle design to drastically reduce power consumption, which is one of the core reasons for their wide application.

However, although the small-cycle system of evaporative condensers is convenient, it requires regular makeup water. Many people may wonder: Are there any special requirements for the quality of makeup water? Today, we will elaborate on this key issue to help you avoid misunderstandings in use.

Core Premise: Clean Water Quality is the Bottom Line

Based on years of practical application experience, evaporative condensers do not have excessively high requirements for makeup water quality, but there is one rigid standard that must be followed—water quality must be clean, and it is strictly prohibited to contain impurities such as sludge and turbidity.

We have found a common misunderstanding in some enterprises: directly using circulating water similar to sewage discharged from other processes as makeup water. Such water has a high sediment content, which is prone to adhering to the outer wall of the evaporative condenser to form a sludge layer. Over time, this will seriously affect the heat transfer efficiency of the equipment, not only offsetting its energy-saving advantages but also possibly shortening the service life of the equipment.

Key Indicators: Two Core Parameters to Remember

Regarding circulating water quality, China has a clear national standard—Code for Design of Industrial Circulating Cooling Water Treatment (GB 50050-2017). Water supplied in accordance with this standard can fully meet the operational needs of evaporative condensers. Among them, two core indicators require special attention:

1. Water Hardness: Required to be ≤ 200 mg/L (calculated as calcium carbonate). The hardness here mainly refers to the content of calcium and magnesium ions in the water. It should be noted that a slight excess of hardness above 200 mg/L is acceptable in practical use, but not excessively. Because the formation of scale requires the water temperature to reach around 60℃, while the circulating water temperature of evaporative condensers is usually controlled below 40℃, calcium and magnesium ions are not easy to precipitate and form scale, so the tolerance for hardness is relatively high.

2. Chloride Ions: Required to be ≤ 100 mg/L. This indicator must be strictly controlled to avoid corrosion of the equipment by chloride ions.

Important Reminder: Turbidity Must Be Strictly Controlled

Compared with calcium and magnesium ions that can be slightly excessive, the control of turbidity is more critical. Even if the water quality indicators are close to or slightly exceed the national standard, as long as the water is clear, free of sludge and suspended impurities, it can be used normally; however, if the turbidity is not up to standard, sediment and other impurities will quickly adhere to the equipment surface, affecting heat transfer efficiency, and subsequent cleaning will also consume a lot of manpower and material resources.

Therefore, it is recommended to carry out necessary pretreatment before the makeup water enters the evaporative condenser to filter out suspended impurities and sediment in the water, ensuring the stable operation of the equipment from the source.

Summary

The requirements for makeup water quality of evaporative condensers are not harsh, with the core being "clear and free of impurities". Priority should be given to using industrial circulating water that meets the GB 50050-2017 standard. Calcium and magnesium ions can be slightly excessive, but the use of turbid water and sludge-containing water must be prohibited, and inlet water pretreatment should be well done. This can not only give full play to its energy-saving advantages but also extend the service life of the equipment and avoid unnecessary fault losses.