Cooling Tower Guide
Cooling towers are large devices that bring cool air and warm water together for a specialized heat exchange process. The result? Thermal comfort inside a building or provision of cool water integral to operations, particularly in refineries, chemical processing, manufacturing units.
Industrial and commercial buildings, including manufacturers, hospitals, schools, apartment buildings, and hotels, require heat and air conditioning. This is where cooling towers come in.
In this blog post, we’ll cover what you need to know about cooling towers, how they work, what cooling tower maintenance entails, and why it’s necessary to extend your unit’s efficiency and life span.
Introduction to Cooling Towers
Large corporations such as manufacturing facilities, petroleum refineries, and power plants install large cooling towers. Other areas where cooling towers are used are in buildings HVAC systems, whether commercial or residential, hotels, and restaurants.
Because of their varying needs, cooling towers come in different sizes—some are even installed on the rooftops of colleges, condominiums, and malls.
The most common use of a cooling tower is to help cool large buildings. These cooling towers are placed inside a heating, ventilating, and air-conditioning (HVAC) unit. This type of HVAC cooling tower is used to remove unwanted heat from a building.
As mentioned, cooling towers come in different sizes, but the right fit for any unit depends on the cooling load of a facility. That determines the cooling tower design that will be ideal for your business operation.
Another aspect to consider is the humidity level in the air where you will place the cooling tower. This depends on the location of the site. For instance, humidity in Orlando, Florida, is a lot more when compared with humidity in Denver, Colorado.
Continue reading to learn about the different types of cooling towers (dry and wet cooling), effective ways of maintaining cooling towers, and essential features of cooling towers.
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Different Types of Cooling Towers
Cooling towers are categorized based on their airflow generation methods, size, and heat resistance methods. Let’s take a closer at each and understand the mechanisms that drive these different kinds of cooling towers:
Water Cooling Towers
There are six types of open-circuit or wet cooling towers: natural draft, fan-assisted, plume-abated induced draft, plume-abated fan-assisted natural draft, forced draught cooling tower, and induced draft.
Based on their design, these cooling tower types are categorized as either counter flow, cross flow, or hyperbolic. Here’s a closer look at the three categories:
Counter Flow Cooling Towers
These cooling towers are created such that air travels vertically, in an upward motion, while water is sprayed in a downward motion.
If you’re wondering how this cooling tower manages to defy the law of universal gravitation, the secret lies in draft fans. The purpose? As the hot water flows downward through the “fill,” air is pumped upwards. Evaporation occurs at this stage, cooling the remaining water in the fill.
These cooling towers are cost-efficient, and they’re easy to clean and maintain. There are also lesser chances of the pipes getting clogged, especially by algae, thereby significantly increasing the life span of the cooling tower.
Cross Flow Cooling Towers
As the name suggests, Cross Flow Cooling Towers are designed so that the water travels vertically whereas the air travels horizontally.
Like the counter flow cooling tower, this unit also operates on the principle of heat exchange as water flows through a “fill.” Air ejected through the fill results in evaporation and subsequently lowers the temperature of non-evaporated water.
This type of cooling tower consumes more power and requires a lot of upkeep. It is also prone to issues such as spray nozzle blockage. Furthermore, it needs greater airflow for the heat conversion to occur successfully.
Hyperbolic Cooling Towers
Have you ever seen gigantic concrete, steel, or alloy inverted-funnel-like structures constantly billowing white steam? Yes, those are hyperbolic cooling towers.
These structures leverage the natural properties of air to induce cooling. The hot, moisture-laden air inside the tower will rise, creating a natural current that allows the cool air from outside to take its place.
These kinds of cooling towers are structurally strong and require minimum energy as they don’t require fans. They’re also low maintenance and have fewer corrosion-related issues.
Dry Cooling Towers
These systems do not require water and air to mingle to dispel heat. In this case, heat is exchanged using cooled air—warm water flows through thin tubes surrounded by cool air.
You’ll most commonly see dry cooling towers being used in the solar industry or plastic industry. Their application also extends to data centers or factory cooling.
Dry cooling towers are of two kinds—indirect and direct.
The advantages of using dry cooling towers are that they’re low maintenance, have a low initial operating cost, and have minimal water contamination and loss. In addition, these cooling towers can work in any environment—extreme heat to extreme cold.
Fluid Cooling Towers
These are also known as closed-circuit cooling towers. In this type of cooling system, water is mixed with glycol and circulated in a coil to remove excess heat.
Fluid cooling towers are perfect for industries where the surface area needs to be free of contaminants.
Still unsure what kind of cooling tower suits your purpose? We’ve chalked up a size-based comparison too!
What Size Cooling Tower Do You Need?
Large Cooling Towers
You can tailor these field-erected towers according to your specifications for structure, design, and plume abatement.
Large in size, these cooling towers are used by power plants and big manufacturing facilities such as refineries and power plants. They are usually assembled at the site by supervisors and field technicians sent by the manufacturer to ensure that they are installed properly and according to specifications.
Package Type Cooling Towers
These cooling towers are manufactured and framed at a facility and assembled at the building site.
Long-lasting materials such as fiberglass-reinforced polyester are used, so these cooling towers are water-resistant and do not corrode. They are relatively smaller compared to industrial cooling towers, and are typically installed at shopping malls, clinics, and offices.
Their compact and light design makes it easy to transport them to the building site without any hassle.
Mechanical Draft Cooling Towers
Unlike natural draft cooling towers, mechanical draft cooling towers use artificial air circulated inside the structure with the help of draft fans.
Comparatively, they are much smaller and can be placed anywhere inside the facility (unlike natural draft towers that need to be placed outside the building).
How To Maintain Cooling Towers
Cooling towers require regular maintenance and repair, without which they may break down and increase your overall cooling tower operation costs and reduce your company’s productivity.
In residential and commercial buildings, well-maintained cooling towers prevent airborne diseases, ensure the health and wellbeing of occupants, employees, and visitors.
By getting maintenance work regularly, you’re increasing your cooling towers’ lifespan, maintaining optimal airflow and water flow, and keeping the pipes from eroding due to corrosion or algae.
Simply put, cooling tower maintenance is critical and needs to be conducted regularly.
What goes into maintaining cooling towers?
- Where there’s water and evaporation, there will be scale (mineral) deposits. Water pipes, spray nozzles, collection basins, etc., must be cleaned regularly to avoid congestion and blockage.
- Cleaning with specific cooling towers chemicals using deep cleaning methods like pressure washing to remove mud or sludge deposits. Water quality will determine how often the tubes get blocked and, subsequently, your cooling tower’s cleaning schedule.
- Keeping the fans, pumps, and motors aligned and working optimally through regular inspection by field technicians is crucial. This will prevent issues caused by lowered airflow, ensure efficient pumping (higher energy efficiency), etc.
- Technicians will also inspect cooling tower parts and remove algae or bacterial build-up. They will also use biocides, etc., to treat the water, and disinfect the entire cooling tower, including pipes, fill, etc.
If you need help with cooling tower repair or maintenance, Square One can assist you with both. They work with all makes and models of natural as well as induced draft cooling towers.
Cooling Tower Parts
It is important to maintain the key components of a cooling tower:
- Cooling tower fill media can be made from wood, polypropylene, or PVC. The purpose is put as much water surface in contact with as much air flow as possible
- Drift Eliminators, made from PVC, help to separate water droplets from air, thereby reducing how much water is lost in the heat exchange process. Eliminators reduce the amount of water that escapes into the discharge air in the cooling tower.
- Nozzles supply water flows through spray nozzles into the cooling towers at a certain pressure to keep the system functioning optimally.
- Mechanical components start with the cooling tower electric motor, which is connected to and turns the driveshaft. Driveshafts transfer power to the gearbox and need to stay aligned so that they can work at full motor speed. The gearbox, or gear reducer, reduces the electric motor’s shaft speed and increases torque to turn the fan. Cooling tower fans must move at a certain speed with minimal vibration to avoid getting corroded and damaged by external environmental factors.
- Tower structures are usually made from chemically treated wood. Over time, the wood deteriorates, and upright support beams and cross beams need to be replaced.
- Cold water basins function as the base of the tower, supporting the main structure. They can be placed just below ground or on top the of the ground. The basin collects and stores cold water.
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Cooling towers play an integral role in the proper functioning of industrial and commercial buildings. They come in different sizes and can be customized, depending on the applications needs and available space.
It’s important to maintain and repair towers so that they remain efficient and safe.
Regardless of whether you have a residential, commercial, or industrial grade cooling tower, Square One can assist you with your repair or maintenance needs.