How Cooling Towers Work & the Importance of Regular Maintenance
How Cooling Towers Work

Cooling towers play a critical role in some HVAC systems, especially in commercial and industrial settings.

In this blog, we will explore the operation of cooling towers, and their purpose, and underscore the significance of consistent cooling tower maintenance.

What is a Cooling Tower?

A cooling tower is a specialized heat exchanger where water and air are used to reduce the temperature of the water. Through the cooling tower’s operation, some water evaporates, lowering the temperature of the fluid that’s circulated back through the system. This process is essential in removing heat from a building space, process, or system.

How A Cooling Tower Works

The operation of a cooling tower involves several steps and many different components.
Here’s how they work: 


Step 1: Warm Water Input

Warm water containing the heat to be removed from the building is pumped through a coil in the cooling tower if it is a closed-circuit design. In other words, the water, or glycol mix, in the closed-circuit loop circulates to a chiller, or a series of heat pumps, in the building. This fluid does not come in direct contact with the water that is in the tower’s cool water basin. In an open system, the water in the HVAC system circulates through the cooling tower and throughout the system. This water has absorbed heat from the building’s HVAC system and needs to be cooled before it can be reused and sent back to the chiller or HVAC system. 


Step 2: Removing Heat

Cooling towers can have a basic on/off operation with a fan, or have several stages of operation to remove heat from the coil or water.

Stage 1 – A circulating pump can be started that pumps water over the fill plates or coil in the cooling tower.

Stage 2 – There can be a damper on the top of the cooling tower that opens at a set temperature, this allows the natural flow of air through the tower.

Stage 3 – If the temperature continues to rise, a fan is started. This fan could be a variable speed fan that starts slowly at 20% of its speed and goes up to a full 100% of speed at a given set temperature.

Important Note About Cooling Tower Maintenance

Over time, the fill plates can become clogged with minerals, debris, or biological growth, which reduces their effectiveness and efficiency. This is one reason why regular maintenance of cooling towers is crucial to keep them functioning properly and to ensure their optimal operation. 


Step 3: Cooling and Evaporation

As the warm water is sprayed into the tower and down the fill, it’s met with ambient air flowing up through the tower (the air is either fan-forced or arrives through natural convection). As the air and water come in contact, some of the water evaporates, and the heat is transferred from the water to the air. This process is supported by the design of the tower which allows hot air to rise and escape through the top as cooler air is drawn in the bottom of the tower.


Step 4: Heat Discharge

The warm air, now carrying the absorbed heat from the water, is pulled out of the tower and into the atmosphere. This is done with a fan located at the top of the cooling tower, but there are many different designs for cooling towers. As there is constantly water being evaporated away from the cooling tower there is a float valve in the cool water basin (or sump). When the water level drops, the float drops, and the valve opens to add water to the system.


Step 6: Recirculation of Cooled Water

The cooled water collects in a basin at the bottom of the tower and is pumped back to the top of the tower again or sent to the HVAC system or chiller, ready to absorb more heat from the building. This continuous cycle ensures the efficient operation of the HVAC cooling system.


The Importance of Cooling Tower Maintenance

Regular maintenance is crucial for the efficient and effective operation of cooling towers. Over time, towers can accumulate scale, algae, and other forms of debris that can significantly affect their performance. Proper maintenance ensures that these systems operate at their peak efficiency, which is critical for minimizing energy consumption and extending the lifespan of the entire HVAC system.


Key maintenance tasks include:

  • Regular cleaning of the tower and fill material to prevent blockages and microbial growth
  • Inspection and maintenance of mechanical parts like fans and pumps to ensure they are functioning correctly
  • Water treatment to prevent the build-up of harmful chemicals and debris that can corrode components and reduce efficiency 

Why Choose TRI-AIR SYSTEMS for Your Cooling Tower Maintenance

TRI-AIR SYSTEMS stands out as a leader in HVAC services, providing top-tier maintenance for cooling towers. With a focus on reliability and customer satisfaction, TRI-AIR offers rapid response times and round-the-clock customer service to ensure your HVAC systems, including cooling towers, operate without disruption.

Opting for TRI-AIR SYSTEMS for your cooling tower maintenance means securing a partner who understands the intricacies of HVAC cooling systems and the critical nature of keeping these systems in optimal condition. Our experienced technicians are skilled in handling all aspects of cooling tower operations, from routine cleanings to emergency repairs, ensuring that your systems are efficient and reliable.

Contact TRI-AIR today (, or learn more about the services that we offer.  



Cooling towers are a vital component of any HVAC system. Understanding how these towers operate and the importance of their maintenance can significantly impact the efficiency and operational costs of your building systems. For expert maintenance and service, look no further than TRI-AIR SYSTEMS, where your HVAC needs are met with professionalism and expertise.

Remember, regular maintenance is not just about preventing breakdowns; it’s about optimizing performance and ensuring efficiency.

Contact TRI-AIR SYSTEMS today to find out more about our cooling tower maintenance services and how we can help keep your HVAC system running smoothly.

Call Us (905) 470-2424