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Why is function of cooling tower Better?

May. 13, 2024
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Cooling Towers | Other Uses of Water | Healthy Water | CDC

What is a cooling tower?

A cooling tower is designed to remove heat from a building or facility by spraying water down through the tower to exchange heat into the inside of the building. Air comes in from the sides of the tower and passes through the falling water. As the air passes through the water, heat is exchanged and some of the water evaporates. This heat and evaporated water flow out the top of the tower in the form of a fine cloud-like mist. The cooled water is collected at the bottom of the tower and pumped back into the plant or building for reuse. Cooling towers provide large scale air-conditioning where land and (or) water are expensive, or regulations prohibit the return of once-through cooling waters 1.

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What are cooling towers used for?

Cooling towers are primarily used for heating, ventilation, and air conditioning (HVAC) and industrial purposes. Cooling towers provide a cost-effective and energy efficient operation of systems in need of cooling. More than 1,500 industrial facilities use large quantities of water to cool their plants 2. HVAC systems are used typically in large office buildings, schools, and hospitals. Industrial cooling towers are larger than HVAC systems and are used to remove heat absorbed in the circulating cooling water systems used in power plants, petroleum refineries, petrochemical plants, natural gas processing plants, food processing plants, and other industrial facilities.

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Cooling towers and Legionnaires’ disease

Cooling towers contain large amounts of water and are potential breeding grounds for Legionella  bacteria if they are not properly disinfected and maintained. Water within cooling towers is heated via heat exchange, which is an ideal environment for Legionella  heat-loving bacteria to grow. Legionnaires’ disease can be acquired when an individual breathes in water droplets containing Legionella  bacteria. The disease was named in 1976, when American Legion members who attended a Philadelphia convention, suffered from an unusual pneumonia (lung infection). Outbreaks due to Legionnaires’ disease from contaminated cooling towers still occur today 3.

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What is a Cooling Tower and How Does it Work?


A cooling tower is a heat removal device that uses water to transfer process waste heat into the atmosphere. Likewise, an industrial cooling tower operates on the principle of removing heat from water by evaporating a small portion of water that is recirculated through the unit.

The mixing of warm water and cooler air releases latent heat of vaporization, causing the water to cool. If you are ever looking down from a high-rise building, you might notice a square unit, with fans on top of it, on the buildings below. That's a water cooling tower.

No one wants to stay in a building with bad air conditioning—at least not for too long. On the other hand, buildings with excellent cooling make you want to return, even if it’s just to enjoy the air. That’s thanks, in large part, to the continued modernization and innovation of the commercial cooling tower system.

What is the purpose of a Cooling Tower?

A water cooling tower is used to cool water and is a huge heat exchanger, expelling building heat into the atmosphere and returning colder water to the chiller. A water cooling tower receives warm water from a chiller.

This warm water is known as condenser water because it gets heat in the condenser of the chiller. The chiller is typically at a lower level, like in a basement. The cooling tower’s role is to cool down the water, so it can return to the chiller to pick up more heat.

How Does a Cooling Tower work?

Air conditioning equipment and industrial processes can generate heat in the form of tons of hot water that needs to be cooled down. That’s where an industrial cooling tower comes in. Overheated water flows through the cooling tower where it’s recirculated and exposed to cool, dry air. Heat leaves the recirculating cooling tower water through evaporation.

This is called evaporative cooling. The colder water then reenters the air conditioning equipment or process to cool that equipment down, and the cooling cycle repeats over and over again.  When the warm condenser goes into the cooling tower, the water is passed through some nozzles which spray the water into small droplets across the fill, which increases the surface area of water and allows for better heat loss thru greater evaporation.

The purpose of the fan on top of the water cooling tower is to bring in air from the bottom of the tower and move it up and out in the opposite direction of the warm condenser water at the top of the unit. The air will carry the heat by evaporating water from the cooling tower into the atmosphere.

Why is an Industrial Cooling Tower Needed?

An industrial cooling tower is a critical component of many refrigeration systems and can be found in industries such as power plants, chemical processing, steel mills, and many manufacturing companies where process cooling is necessary. Also, a commercial cooling tower can be used to provide comfort-cooling for large commercial buildings like airports, schools, hospitals, or hotels.

An industrial cooling tower can be larger than an HVAC system and is used to remove the heat absorbed in the circulating cooling water systems used in power plants, petroleum refineries, petrochemical plants, natural gas processing plants, food processing plants, and other industrial facilities.

With the increased rate of the population all over the world, there has been a huge rise in the rate of needs and requirements by the world for manufactured products. This has forced the industrial sector to manufacture more and more products every day, which generates more manufacturing process heat.

The machines and processes of industries that generate tremendous amounts of heat must be continuously cooled so that those machines can continue to operate efficiently. The most efficient, effective, and least expensive solution to removing this heat is the installation of an industrial cooling tower.

Cooling Tower Types

Cooling tower systems are often vital to industrial processes. These tall, open-topped, cylindrical structures are responsible for cooling water generated from industrial or HVAC comfort cooling airflow. The different types of cooling towers are identified by the classification of the draft (natural or mechanical) and by the direction of airflow (counter or cross).

Natural Draft Cooling Tower Systems

are usually used for large power plants and industries with infinite cooling water flow. The tower operates by removing waste heat by way of rising hot air that is then released into the atmosphere. These towers are tall and have a hyperbolic shape to induce proper airflow.

Mechanical Draft Cooling Tower Systems

These towers have air forced through the structure by a fan that circulates air through the tower. Common fans used in these towers include propeller fans and centrifugal fans. While Mechanical draft towers are more effective than natural draft towers, they consume more power and cost more to operate as a result.

Crossflow Cooling Tower Systems 

have a design that allows the air to flow horizontally through the fill and the tower’s structure into an open plenum area. Hot water flows downward from distribution basins. However, fans and motor drive require weather-proofing against moisture which can lead to freezing making it less efficient.

Counterflow Cooling Tower Systems

have a design where the air moves upwards and the counter-current, with hot water, falls downward to cool the air. This allows for maximum performance out of each plan area and helps minimize pump head requirements. Also, a counterflow cooling tower system is less likely to ice up in cold weather conditions and can save energy in the long run. All Delta Cooling Towers are counterflow and all include these advantages.

Induced Draft Cooling Tower Systems 

are typically mounted with a fan at the top of the cooling tower, which allows hot air out and pulls air throughout. The high exiting air velocities reduce the chance of re-circulation. To avoid the entrapment of water droplets in the leaving stream air, drift eliminators are used. Induced draft towers are more efficient as they use 30% to up to 75% less energy compared to forced draft designs.

Forced Draft Cooling Tower Systems 

This cooling tower system is similar to induced draft, but the basic difference is that the air-moving fan is placed at the base of the cooling tower, which allows the air to blow through from the bottom. Their use is limited due to water distribution challenges, high horsepower fans, and the possibility of re-circulation.

What is the best material for a Cooling Tower?

Water-cooled systems are primarily made from three materials: Metal, fiberglass, and plastic. As you know, metal can rust and corrode, and whatever’s inside of it can begin to leak over time.

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To no surprise, a metal cooling tower only has an average shelf life of up to only 15 years and requires maintenance with epoxy paint, sealants, and more. That maintenance can lead to downtime for your business. This is why metal is now being replaced with better technology. Fiberglass cooling tower manufacturers, although providing a better alternative to metal, are still prone to cracks and wear which can lead to long-term higher maintenance costs. 

What are the advantages of using engineered plastic?

An engineered plastic cooling tower is designed to stand up to wear and tear. It doesn’t rust or chip—and it can weather harsh environmental conditions. It also requires almost zero maintenance.  High-density polyethylene (HDPE), a best-in-class engineered plastic used by Delta Cooling Systems, is seamless and resistant to environment-induced corrosion, unlike metal or fiberglass cooling towers. With a life expectancy of more than 20 years, you can install it once knowing you will not have to worry about it afterward. 

Advancements in the manufacturing and design of today’s engineered plastic towers changed the use of cooling towers from a valuable support tool, to one of productivity and savings in the cost of a cooling tower. Factory-assembled commercial cooling towers became popular at the same time when engineered molded plastics became more desired over the galvanized metal models that once dominated the industry. There are many reasons why you might want to consider an engineered plastic cooling tower to reduce costs and better meet your process needs:

  • Life expectancy - A standard metal cooling tower has casings with thin sheets of galvanized steel. These sheets usually have welded seams that can deteriorate within a year and will require re-welding, patching, or coating to prevent leakage. Additionally, the treated water tends to attack the galvanized metal, essentially wearing it out in an extraordinarily short time. Environmental conditions such as sunlight, pollution, salt air, and harsh process chemicals also contribute to galvanized steel’s early demise. Even ambient air pollution can affect galvanized steel, leading to premature failure. Since metal expands and contracts, depending on the temperature, repeated cycling causes stress that can also accelerate corrosion, rust, and leakage. Even low-grade stainless shell options, series 300 stainless steel, are attacked and worn out against water treatment chemicals and environmental factors.
  • Flexible modular design - In the past, a plastic cooling tower was too small for many industrial processes. For that reason, galvanized metal cooling towers were traditionally used for most applications above 250 tons but that situation has changed dramatically. Delta, for instance, has introduced its TM Series® of factory-assembled plastic towers that can be combined to provide up to 2,500 cooling tons in a single, modularized unit. Modular cooling towers also facilitate the use of an extra margin of cooling capacity that can be advantageous in adjusting to operational heat load or outflow changes, or in upgrading to meet future cooling requirements.
  • Continuous, more economical operation - Engineered plastic can also reduce the expected and inconvenient consequences of operating a cooling tower, which include: electric power usage, water-treatment chemicals, labor and materials for maintenance, and unscheduled process downtime for cooling tower repairs. Maintenance and repairs usually mean process interruptions, the costliest of all problems related to cooling towers.
  • Easier installation - The basic design advantages of the latest plastic cooling towers also include easier installation, especially on rooftops, because a lightweight plastic shell weighs as much as 40% less than a steel tower while being 5-10 times thicker. When modular cooling towers are combined in a cluster, installation is often faster and easier.

What is the connection between Cooling Tower systems and Legionnaires' Disease?

According to the Centers for Disease Control and Prevention (CDC), water cooling towers can be a breeding ground for Legionella bacteria, the microbes that cause Legionnaires’ disease. Here’s why: Bacteria thrive in warm, wet conditions, making watercooling towers an ideal environment.

As a result, people can get Legionnaire’s disease, which can cause pneumonia, when they breathe in water droplets dispensed from HVAC systems that contain Legionella bacteria. In fact, a 2017 study by the CDC found six Legionnaires’ outbreaks in New York City that resulted in 213 cases and 18 deaths. Three of those outbreaks were linked to cooling towers.

To address this public health concern and liability, companies are treating the water inside of their industrial cooling tower with antimicrobial substances that kill the bacteria. For other water treatment applications, an air stripper is often used. As another precaution, plastic cooling tower systems can be manufactured with antimicrobial resins built into the unit materials and components to provide an additional layer of defense against Legionella. Find out more about the anti-microbial product technology at Delta Cooling Towers.

Is a cooling tower environmentally friendly?

With the increasing concerns about meeting green standards and improving ROI on capital equipment expenditures, there are some standards to consider. 

A systematic approach to cooling tower greenness will improve sustainability, increase energy efficiency, add water conservation, and create a smaller carbon footprint; all while improving some cost ramifications involved in achieving such green goals. Businesses can save up to 40 percent on energy costs.  While conventional cooling towers, often constructed with sheet metal cladding, are environmentally challenging and maintenance intensive, the alternative of using cooling towers with molded seamless plastic is immediately beneficial to both the environment and your bottom line.

Traditional metal towers, which last only a few years in many applications, encounter environmental and economic issues including increased chemical use, higher maintenance costs, replacement costs, and disposal requirements. Engineered HDPE plastic design cooling towers allow the most aggressive water treatment options available. This can allow users to run at higher cycles of concentration, thereby saving make-up water. This can save tens of thousands of gallons of water per year. 

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