Environmental regulations regarding intake and discharge issues have required a transition to the use of cooling towers or air-cooled condensers, rather than traditional once-through cooling from a local water source such as a river or lake. Proper chemistry control is vital to steady heat transfer and stability in cooling towers. Cooling towers and the tower fill are susceptible to scale and deposit build up that over time interferes with heat exchange. In addition to continuous chemical feed and monitoring, specific tower cleaning must be done.
Contact between the hot water return and the cool air coming through the tower greatly effects cooling tower performance and efficiency. Cooling tower fill is designed to enhance heat transfer and optimize air/water contact. Proper chemical treatment during normal operation is essential to prevent scaling and fouling problems.
Microbiological fouling issues in cooling systems are perhaps the most detrimental of all cooling system issues. For this reason, practically all systems have as primary treatment some type of oxidizing biocide, typically bleach but in some cases gaseous chlorine, bleach/sodium bromide, chlorine dioxide, monochloramine, and monobromamine may also be included.
The best approach is to prevent deposition from ever occurring. The selected fill type should be compatible with realistic expectations for the system, considering the quality of the water that is flowing in, microbiological control, use of pre-treatment equipment, as well as the possibility for external contaminants that might enter the tower through the air or by way of fluid leaks.
EvapTech Series EC cooling towers provide a variety of counterflow fills to meet all unique application needs:
The TechClean Family of vertically offset flute fill products are optimized for highly efficient thermal performance with a significantly reduced tendency to foul. TechClean has a higher allowable TSS and microbial limit to allow operation with higher concentration multiples and a corresponding blowdown reduction, which substantially reduces water consumption. Unlike competitive high fouling cross corrugated designs, Evaptech’s standard TechClean fill product offers exceptional thermal performance as well as problem-free operation.
VertiClean fill was developed to specifically address those applications in which high circulating water contaminant levels would result in unacceptable fouling potential in either cross corrugated or vertically offset flute fills. VertiClean has vertically oriented flutes throughout its air flow path to provide the most effective fouling resistance. At the same time, its textured sheets retain reasonable thermal efficiency and low pump head compared to splash fill alternatives.
In the unlikely event that plot plan is critical and very clean water conditions exist, EvaPak fill can provide the best fill choice. Cross corrugated in design and tight spaced to maximize surface area, EvaPak offers the highest efficiency fill product available per unit volume. However, heat transfer comes at the expense of high pressure drop and parasitic power consumption.
SplashPack open mesh fill offers an alternative to conventional splash fill products when TSS and other contaminants eliminate the potential for using film fills. Featuring a compact pack arrangement, SplashPack reduces or eliminates the pump head penalty of traditional splash fills and its polypropylene construction represents a competitive alternative for high temperature process applications.
In applications that involve fibrous or large solids circulating water, wide spaced splash fill products may be the only acceptable arrangement. Opti-Bar grids have large square openings and in most cases are arranged on 8″ vertical centers to withstand even the most difficult water conditions. In addition, polypropylene construction can endure harsh chemicals and high temperature applications.
Lathrop Trotter is your source for Evaptech field erected cooling tower systems and aftermarket service. Contact us to discuss your application.