05-14: It's time to Rethink Cooling Tower Filtration

The dissipation of ambient or process heat in large HVAC systems, manufacturing facilities, power generation plants, refineries, metal mills and forges, chemical plants and food processors is most often accomplished by cooling towers. These simple structures facilitate the transfer of unwanted energy (heat) from a transport liquid (usually water) to the atmosphere. The bane of cooling towers, with relation to efficient heat transfer and pathological risks to employees is suspended solids. These solids can originate in the process, in the piping, from the atmosphere or from internal biological growth. Side stream filtration is the most commonly used methods of maintaining minimal suspended solids in the cooling system. Present day systems rely mainly on two established methods of suspended solids removal. The first utilizes cyclonic principles and can remove only high specific gravity solids leaving organics such as algae behind. The other method is granular media filtration that generally requires very high volumes of flush water during its cleaning process. This filter type also accumulates particles of high specific gravity within its housing causing the eventual costly replacement of its media. Both of these methods require high energy inputs to operate. Automatic self cleaning screen filter technology not only removes both organic and inorganic solids regardless of specific gravity but also requires very little energy to operate and conserves coolant additives by using very little coolant liquid for the self cleaning process. By incorporating the cleaning cycle into the blowdown process of the cooling tower system the unwanted loss of coolant can be completely eliminated. This manuscript will address the operational processes of automatic self cleaning screen filtration technology and review a number of real world case studies in both commercial HVAC systems and manufacturing processes to prove the advantages over traditional cooling tower treatment systems.