After the installation of the non-invasive product to prevent scaling without the use of chemicals, water consumption in a cooling tower was reduced to 2 million gal the next year.

A 500-ton cooling tower in North Carolina was using 4.5 million gal of chemically treated water annually. After the installation of the non-invasive Scalewatcher product from Scalewatcher North America Inc. to prevent scaling without the use of chemicals, water consumption was reduced to 2 million gal the next year.

At a price of water/sewage of $0.0007/gal, the 50 percent reduction in use represents a total savings of $17,510.60 annually. By setting the total dissolved solids (TDS) controller to a setpoint of 1,800 ppm instead of 1,600 ppm, the savings become greater, according to Oxford, Pa.-based Scalewatcher. The approach temperature in the chiller condenser is now running at 3.5 to 3.8°F, which is the same as when the cooling system was installed.

The Scalewatcher system uses electric and magnetic fields to promote crystal growth in the bulk of the water. According to the company, crystals do not have a surface charge and will not adhere to pipe walls or other surfaces. They float with the water until discharged by regular blowdown. As chemical scale inhibitors increase the TDS of the cooling water very quickly, blowdown starts as soon as the setpoint of the TDS level is reached in an automated blowdown system. By not using these chemicals, it will take longer before the setpoint is reached, which is where the savings come from, says the company. The setpoint can be set at a higher level to generate more savings.

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