Effects of Water Quality on Water Treatment Chemical Performance of Cooling Water Systems for Copper Tubes in Absorption Chiller/Heater

Abstract

In opened circulator cooling system, water treatment should be conducted to prevent pitting corrosion of copper tube and generation of Legionella spp. In this system ionic components in cooling water are gradually concentrated by evaporation of the water and the high concentration may affect the pitting corrosion and the number of Legionella spp. Suitable treatment of the cooling water is required in which some chemicals are added to solve the two problems. In this study, field tests were conducted using copper plates and tubes with different amounts of residual carbon. Comparison between the results of the tests in flowing and stagnant water suggested that corrosion evaluation was made possible by the stagnant–water test using the copper tubes. The pitting corrosion evaluation and Legionella spp. measurement were conducted at 10 points with different water qualities by the stagnant–water test in which the newly developed water treatment chemical was added. The results showed that the developed water treatment chemical achieved excellent performance on pitting corrosion prevention and on maintaining Legionella spp. below the limit of detection at all the locations.