Water system of central air conditioning circulating

The central air conditioning circulating water system is composed of two parts, the cooling system and the refrigeration system, and is an important component for the central air conditioning to achieve heat exchange. In the system, water is used as a heat exchange medium, which often causes pipe corrosion, shortening the service life of equipment and pipes; it also causes the fan coils in the closed-loop refrigeration system to be constantly blocked by the corrosion products of the pipe materials, causing poor water flow and even causing the air conditioning to not cool. Open-loop cooling systems are affected by harmful substances entering the cooling water in the air, as well as by the cooling tower to cool the circulating water, resulting in more serious corrosion, scaling, microorganisms, and sludge in the open-loop cooling water.

Because the scaling, corrosion, and algae growth in the central air conditioning cooling water system are not formed in the short term and will not have a destructive impact on the system in the short term, they often do not receive enough attention from operating managers. Additionally, the cooling water system is simple and designers often do not pay enough attention. Generally, the treatment of cooling water is related to drainage and HVAC professionals, but most of the time the cooling water system is designed by HVAC professionals, which leads to inadequate design from the beginning. In the design process, the treatment methods for the cooling water system are also different from those for the refrigeration water system due to its tendency to form scaling, corrosion, and bacteria and algae growth.

The treatment methods for cooling water can be divided into chemical and physical methods. Chemical method: Currently, large-scale cooling water systems mostly use chemical methods, so it is necessary to add scale inhibitors, corrosion inhibitors, sterilization and algaecide agents and cleaning agents in the cooling water, thus forming a full set of water treatment technology for cooling water. This can be used as a reference for the design of large air conditioning cooling water treatment. The principle of chemical treatment method is not complicated. Because scale inhibitors can ensure heat transfer efficiency and save energy at the same time, corrosion inhibitors, sterilization and algaecide agents can reduce the corrosion of water to equipment and extend the service life of equipment, so it is widely concerned by the public, and major water treatment companies around the world develop this technology as a priority. Chemical treatment method was first used in hot water boilers and ship water treatment, in recent years, the method is also used in cooling water systems, the commonly used drugs are solid crystal silicate membrane corrosion inhibitors. Practice has shown that the following points need to be noted: different membrane agents have different solubility temperatures, for the addition of tanks installed on the circulating water system, the water temperature can often reach the solubility temperature, while for the addition of tanks installed on the water supplement system, it is especially important to prevent low water temperature. If the water temperature is too low, the solubility of the membrane corrosion inhibitor will be poor and it will affect the corrosion inhibition effect.

Physical method: Due to the increasing attention to environmental protection and the risk of secondary pollution caused by traditional chemical methods, physical methods have been increasingly valued in recent years. Physical methods are a relatively ideal water treatment method because they have low operating costs, are easy to use, easy to control, and are pollution-free. In fact, as early as the 1960s, some companies have shifted their attention from chemical methods to the development of physical methods. To date, the physical methods that have been applied include magnetic force method, electrolytic method, ultrasonic method and electrostatic method. The electrolytic method can inhibit the adhesion of water scale, but the descaling is not thorough and it has the danger of electrolytic pitting. The magnetic force method applied early had poor stability, long-term use could not control scaling, and it was necessary to regularly clean the accumulated iron oxide in the controller. On the other hand, the electrostatic method overcomes the shortcomings of the above methods, and in addition to preventing scaling and solubilizing scale, it also has significant sterilization and algaecide effects. However, the electrostatic method and electronic water treatment method have relatively weaker corrosion inhibition effect compared to specialized chemical corrosion inhibitors, and in general air conditioning cooling water systems, it may not be necessary to consider other corrosion inhibition methods. In some systems with higher corrosion inhibition requirements, it is best to use physical methods and add appropriate amount of corrosion inhibitors for better results.