Cooling towers are expensive, ranging from a few thousand to several million dollars. Like any costly investment, you want to maximize the value of your cooling system. To get the most out of your cooling tower, you need to keep it running efficiently, which, in turn, requires regular upkeep.
One critical aspect of cooling tower maintenance often flies under the radar until it’s too late – filtration. Without proper filtration, your cooling tower will be home to fouling, scaling, and corrosion. These problems can lead to energy loss and costly breakdowns.
In this blog post, we will walk you through the different types of filtration methods and how they can benefit your cooling tower.
What Is Cooling Tower Filtration and How Does It Work
Most cooling systems, particularly evaporative cooling towers, rely on water to control the temperature in buildings or industrial processes. While water is the perfect heat exchanger, it usually comes with one major drawback – contaminants.
Common contaminants include dirt, dust, debris, and biological matter like algae or bacteria. These contaminants can lead to several issues, including corrosion, fouling, reduced heat exchange efficiency, and damage to the system. They can clog pipes and reduce water flow, which affects cooling tower performance.
As the efficiency goes down, your cooling system has to work harder, which means more energy bills and frequent breakdowns. With a carefully designed filtration method, you can trap and remove these contaminants before they can reach the fill media and other sensitive parts of the cooling tower.
Common Cooling Tower Filtration Methods
Most types of cooling towers rely on one of the two filtration methods — side-stream and full-flow filtration. We recommend consulting a professional to see which method best works for your system.
1. Side-Stream Filtration
This method continuously filters a portion of the circulating water, typically between 5% and 15%. It minimizes fouling and improves water clarity, reducing the risk of particle buildup.
One of the major advantages of this filtration method is that you can maintain it without shutting down the whole cooling system. This helps you avoid planned maintenance downtime. It’s also an economically feasible solution, especially in high-volume systems, since it filters only a portion of the water.
2. Full-Flow Filtration
This method cleans all the water moving through your cooling system. It’s ideal for high-contamination environments, providing comprehensive protection against inefficiency and costly breakdowns.
Although this filtration method is highly effective, it’s often expensive, especially for high-flow rate systems. Secondly, you cannot clean it without shutting down your entire cooling system, which can result in planned downtime.
Both cooling tower filtration techniques are effective but cannot prevent solids from accumulating in the sump or tower pool.
Common Types of Filters
Whether it’s side-arm or full-flow filtration, most cooling towers rely on different filters to keep problems like fouling, scaling, and corrosion at bay.
1. Screen Filters
Screen filters use a mesh screen to trap contaminants as water passes through. They are simple and effective for filtering larger debris like leaves or dirt, but require regular cleaning to prevent clogging.
2. Sand Filters
Sand filters use a bed of sand to trap suspended solids in the water. As the water flows through the sand, contaminants get trapped. These filters are better suited for slow flow systems, as the water must pass through the sand slowly to capture the solids. However, they are effective for removing fine particles and are relatively low-maintenance, making them a popular choice for most cooling towers.
3. Centrifugal Separators
These filters use centrifugal force to spin water, separating large particles from the flow. The contaminants get pulled downward, past the collection plate, and the clean water returns to the cooling tower. They don’t require filter media replacement, making them a durable, low-maintenance solution for removing larger contaminants.
4. Bag and Cartridge Filters
These filters use a bag or cartridge to capture contaminants. They provide fine filtration and are easy to replace or customize based on contamination levels.
5. Particle Filters
Particle filters can capture small positive and negative solid particles in the water using electrical charges. They are typically used when finer filtration is required, helping to prevent fouling and scaling. Although highly efficient, these filters are more suited for low-flow side arm filtration.
Why Cooling Tower Filtration Matters
Cooling tower filtration helps prevent four problems — biological contamination, fouling, corrosion, and scaling. This can boost your cooling system in different ways.
1. Improved Efficiency
Fouling and scaling significantly reduce heat exchange efficiency. As contaminants build up, the system works harder to maintain desired temperatures, increasing energy consumption. Cooling tower filtration prevents this buildup by continuously removing particles from the water, ensuring optimal heat transfer and lowering energy costs.
2. Extended Lifespan
Corrosion and wear are major threats to cooling tower components, especially when dirt and biological matter are present. These contaminants can cause erosion, damage internal parts, and lead to frequent breakdowns. By filtering out contaminants, you protect your equipment from unnecessary damage, helping it last longer and reducing the need for untimely replacements.
3. Lower Maintenance Costs
Without cooling tower filtration, contaminants accumulate rapidly, leading to clogged pipes, fouled heat exchangers, and increased system strain. This results in more frequent cleanings, repairs, and even unplanned downtime. With an effective filtration system, you can minimize these issues and reduce the need for constant maintenance.
4. Better Water Quality
Filtration improves water quality by removing debris, microorganisms, and other harmful substances, which lowers the risk of Legionella and other waterborne pathogens. This also means your system might need fewer chemical treatments, resulting in a lower environmental impact.
Choosing the Right Cooling Tower Filtration System
Selecting the best cooling tower filtration system depends on several factors. Here’s a list of a few common factors you might want to consider.
1. Location
Where will your cooling tower go? If it’s in an arid area with plenty of dust, you might want to install a more robust filtration system to handle higher contaminant levels.
2. Space
Some filtration systems, like sand filters, take up more room than others. Check the available space around your cooling tower when choosing the filtration system.
3. Flow Rate
Flow rate determines the size and type of filtration your system requires. Higher flow rates require filters that can handle larger volumes of water.
4. Filtration Level
Different systems provide varying levels of filtration. For fine particles or biological matter, more advanced systems like particulate or cartridge filters are a perfect fit.
5. Contaminants
The types of contaminants present in your water—such as dirt, algae, or chemicals—will also dictate the filtration method. Some filters, like screens, are better suited for large particles, while others, such as sand and particle filters, target finer debris.
6. Costs
Budget plays a crucial role in your decision. While some filtration systems may have higher upfront costs, they can save money over time with reduced maintenance and energy consumption.
Get The Right Cooling Tower Filtration System
Filtration is a critical part of maintaining your cooling tower. It prevents damage, boosts efficiency, and extends the lifespan of your equipment. Investing in the right filtration system can save you money on maintenance, repairs, and unplanned downtime.
We recommend hiring a professional to select and install your filtration system. Pinnacle CTS is a leading cooling tower expert in the greater tri-state area. We specialize in installation, maintenance, cleaning, and emergency repairs. Our customized solutions will keep your tower running efficiently and safely.
Contact us to know how we can help.
