Closed circuit cooling systems, also known as chiller circuits, can be subject to corrosion due to a variety of factors. Chiller systems contain multiple types of metals: copper in heat exchangers, aluminum in cooled equipment, and black (carbon) steel in the piping. The presence of different metals in the same system is a primary cause of galvanic corrosion.
Another common cause of corrosion in closed circuit cooling systems is the dissolved oxygen present in the chiller water, especially when the system is not pressurized and oxygen is regularly introduced into the system.
Corrosion in chiller systems can be prevented by adding corrosion inhibitors to the closed circuit cooling water. It should be noted that each metal in the chiller circuit requires a specific type of corrosion inhibitor, and the chemical to be used must be selected accordingly.