Description
The term “closed water system” refers to a water system that is used to provide heating, cooling, or both for industrial processes or facilities. The system is sealed (closed), sometimes under pressure, and is not open to the atmosphere. No evaporation takes place and, with good operation, water is lost only minimally from the system. In general, water treatment for closed systems is much easier than for open systems. Makeup water is needed only to replace seal leakage and other incidental leakage. Because of the small makeup water requirements of these systems, they require little chemical treatment, which can be added intermittently as needed. Once properly treated, the system water does not form scale and has little or no corrosion potential. Two main types of closed water systems are used at military installations: hot water closed heating systems and chilled water closed cooling systems.