Chapter 5 - Cooling Water Systems

Abstract

This chapter examines the types of cooling towers, the water conservation opportunities both voluntary and non-voluntary, alternative water sources, factors to consider in water treatment of cooling water systems and finally the role water-treatment specialists in managing water use in cooling water systems. Comfort cooling, machines and industrial processes all generate a large amount of heat. This heat must be dissipated continually—and flowing water is a good medium to remove heat—which is dissipated through evaporation. Industries such as steel, aluminum, chemical and oil refining involve a number of heat-intensive processes. To control these processes and protect process-equipment from overheating, cooling water is used to transfer waste-heat from the process. Cooling water use—and associated evaporative losses—constitutes the highest consumptive use of water in most of these industries. Water more than any other medium is used for cooling because it is readily available, cheap, has an ability to absorb large amounts of heat per square area, and can be discharged to the public utility sewers, creek or sea. There are a number of water sources that can be used as cooling water such as potable water, river water, ground water, sea water and recycled water (tertiary treated sewage effluent) and other process streams. Salt water is abundantly available at coastal locations. The use of ground water for cooling purposes is now under increasing scrutiny. There are three types of cooling water systems: once through, closed circuit and open recirculating.