The cooling tower is a heat rejection device that cools the condenser water by evaporation in a moving air stream. The tower behaves like a large air washer. Anything that is picked up in the air stream, such as dirt, leaves, debris, pollen, microbes, etc., ends up in the bulk water. As the circulating water is evaporated, the latter solid materials become concentrated in the bulk water.
A water treatment program is designed to protect the cooling tower, evaporative condensers, water cooled condensers, piping and accessories from scale, corrosion and biological fouling. Scale is the result of precipitation of dissolved solids from the recirculated water on heat transfer surfaces.
As the tower performs its functions and as water is evaporated, solids in the water are left behind. Without a treatment program these solids plate out on the exchanger tubes. As the dissolved solids concentration increases in the tower water, solids precipitate from the water and become sediment. Pumps, exchangers, and piping can become severely fouled. Scale formation acts like an insulator and reduces heat transfer. When this occurs, pumps, compressors, fans etc. are less efficient and must work harder and longer. The result is less cooling and higher power consumption. When the scaling reaches a meager 1/32 of an inch, the power consumption is increased by 25%. At 3/64 of an inch, the power consumption is increased by a whopping 49%.
Scaling generally will be followed by some degree of corrosion and fouling. Products of corrosion are oxides and hydroxides of the systems metals. Initially, as a thin fine film, the oxides offer a slight degree of protection to the base metal. But continued and uncontrolled, the corrosion will deteriorate the metal, pumps, tower and tubes.
The NuChem Chemical Treatment Program is designed to add very specific chemicals to depress the dissolved solids from precipitating and to prevent corrosion as a result of scaling and fouling. Microbiological growth is addressed by continuous injection of a biocide.NuChem biocides are EPA registered. NuChem has its own oxidizing biocide, registered in New York State, that is very effective in controlling legionella and other microbiological growth in cooling towers.
A NuChem Chemical Treatment Program will control the scaling and corrosion in the system and provide savings in power cost and mechanical efficiency. Untreated systems are noted for poor efficiency and high maintenance. The replacement cost should likewise be a factor of consideration. Treated units have an operating life of 2 to 3 times an untreated system.
Cooling towers properly operating under a well established maintenance and chemical treatment plan can provide an annual cost savings of 40-45% compared to air cooled systems.
NuChem's experience, achievements and knowledge of cooling systems have gained recognition in controlling legionella in many cooling towers scattered throughout New York City and the State. NuChem's trained technical staff and other supporting personnel are readily available for consultation and to assist you in complying with the new cooling tower regulations recently enacted by both New York City and New York State.