Cooling towers reduce water temperature in air conditioning and industrial processes. Open and closed circuit towers, cubic and circular towers. Examining characteristics and technical details allows for determining the best purchase price.
A guide to checking and choosing types of cooling towers
A cooling tower is for cooling the water circulating in the condenser of the air conditioning systems, power plants, refineries, and various other industries, using heat exchange by the mass transfer process. In cooling towers, water droplets fall onto packings or interface elements (such as boards) that spread the water over their surfaces, increasing wet surfaces and reducing water flow speed.
This process creates more opportunities for sufficient heat exchange between the incoming water flow and the air passing through the cooling tower, effectively decreasing the water temperature within the cooling tower.
Application and uses of cooling tower
Cooling towers are generally used in the following places:
Medical centers
Heavy industrial equipment
Power plants
refinery
Cooling water supply for the condenser of water chillers
Manufacturing factories
Wood, molding, and casting industrial factories
Choosing the Right Capacity for a Cooling Tower
When choosing the appropriate capacity for a cooling tower, it is essential to consider that the maximum temperature difference between the “input and output water” from the cooling tower (ΔT) will always be lower than the difference between the “input water temperature and the wet bulb temperature”. In a simpler explanation, the minimum temperature of the water exiting the cooling tower will consistently be a few degrees higher than the humid air temperature at the location where the cooling tower is installed. For instance, in cities such as Tehran, Mashhad, Karaj, Isfahan, Shiraz, Erbil, Kabul, Sulaymaniyah, Aleppo, Mosul, Kirkuk, and others with similar climates during summer, the maximum temperature of humid air is approximately 23 ℃, the minimum temperature of the water leaving the cooling tower will be around 26 ℃.
Factors to Consider When Choosing the Cooling Tower Capacity
Another important aspect is that even under optimal conditions and dry weather, a cooling tower's ability to decrease output water temperature compared to input water is limited to around 15 ℃. Furthermore, suppose the output water temperature of industrial processes in a factory in the city of Tehran is high and needs to be reduced to around 26 ℃, using one, two, or even three open-circuit cooling towers in series. In that case, ensure that the water entering the first tower isn't hot enough to damage the cooling tower's packing. Consequently, if an open-circuit cooling tower is used to lower the water temperature of production processes, the water entering the tower should not exceed 55 ℃.
Suppose the water temperature is higher than this. In that case, other methods should be employed to reduce it, such as exposing the water to ambient airflow or using water-to-air plate heat exchangers before entering the cooling tower. Also, the lower the relative humidity of the air in the place where the cooling tower is installed, the lower the temperature of the moist air in the place, and as a result, the cooling efficiency and the decrease in the temperature of the water leaving the tower will be higher!
Notes:
An important point regarding the calculation of the capacity and selection of the cooling tower for all types of water-cooled air conditioning projects and cooling towers required for the production line processes of workshops or industrial factories accuracy and checking the weather and climate conditions of the project site. Especially if the relative humidity and temperature are humid in the summer.
Suppose the project is in an area with a moderate climate, such as Tehran, Karaj, Mashhad, Shiraz, Kermanshah, Khorramabad, Semnan, Isfahan, Sulaimaniyah, Erbil, Mosul, Aleppo, Mazar-e-Sharif, Kabul, Kirkuk, Tabriz, etc. The amount The heat transfer and water temperature reduction of the cooling tower is somewhat different based on the moist temperature of the ambient air compared to hot and dry climatic conditions such as the cities of Yazd, Kerman, Zahedan, Zabul, Baghdad, Oman, Medina, Karbala, Najaf, etc.
Cooling Towers Types (Material & Function)
The overall function and the structural materials in common use on cooling towers for HVAC projects include:
Body Material: Galvanized, Fiberglass, and Concrete
Airflow Suction: Natural and Forced (Mechanical Current)
Airflow and Water Synergy: Crossflow and Opposite Flow
Water Distribution System: Watering Nozzle - Basin - Watering arms
Body Shape: Round and Square
Operation: Open Circuit and Closed Circuit
Open Circuit Cooling Tower
Open circuit cooling towers are those regular cooling towers used in air conditioning systems where the water (heat transfer fluid) is cooled after entering the tower and spraying on the packings (which increases the contact surface with the airflow inside the tower). After collecting the water in the lower pan of the tower, it is pumped back to the heat exchange cycle.
When choosing an open circuit cooling tower, the following information must be considered:
Cooling tower shape (round or square)
Cooling tower body material (galvanized or fiberglass)
Water flow rate for the condenser or cooling tower (3 GPM per ton of refrigeration for compression chillers and up to 5 GPM per ton of refrigeration for absorption chillers)
Dry and wet bulb air temperatures of the cooling tower installation environment during summer
The temperature difference between the input and output water in the cooling tower.
Difference between the temperature of the water leaving the cooling tower and the wet bulb temperature of the ambient air (Approach Range for industrial use)
The cooling tower's capacity and flow rate are proportional to the desired chiller capacity in terms of a ton of refrigerating (TR or TOR) or proportional to the volume and temperature reduction of circulating water in industrial processes and factories.
Note: In cooling towers used for industrial, telecommunications, etc., which are also used in the cold seasons of the year, the use of electric heaters (elements) in the pan of cooling towers is required to prevent water freezing and damage to the device.
Open Circuit Cooling Tower Exterior Parts
External components and components of the open circuit cooling tower The external components and parts of the open circuit cooling tower are:
Fan stack (throat)
Louver (air shutter)
panel (the shell)
Pan
Column
Closed Circuit Cooling Tower
In closed-circuit cooling towers, water is sprayed onto the packings while air flows through the tower, cooling the circulating water. This water comes into contact with a coil containing a heat transfer fluid, such as water or oil, which reduces the temperature of the fluid flowing through the closed-circuit coil. Due to the additional equipment needed, such as heat exchange coils and pumps, closed-circuit cooling towers are generally more expensive than open-circuit ones.
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Hybrid Cooling Towers
Hybrid means combining two or more different approaches to create a better approach. Therefore, it can be said that the hybrid cooling tower is a special and complete combination of the closed circuit and open circuit cooling tower, designed to improve the overall performance, increase efficiency, and take advantage of the advantages of these two types of cooling towers. Due to its special design, the hybrid cooling tower has higher dimensions and height and a higher initial construction cost than open-circuit and closed-circuit cooling towers.
Also, the average annual water consumption in the hybrid cooling tower has been greatly reduced, called a low-consumption hybrid cooling tower. In this method, the cooling fluid passes through the coil of the cooling tower (such as a closed-circuit tower) and is cooled. It passes through the heat exchanger or condenser and is cooled again in the vicinity of the cool water entering from the pan of the hybrid cooling tower.
Dry Cooling Towers
Dry cooling tower refers to air condensers of compression refrigeration systems or air-to-fluid heat exchangers (air coolers), which act like a heat exchanger between water and air. In this system, water and air do not have any direct contact with each other, so water does not evaporate (in this way, water consumption in the air-cooled condenser is zero).
The operation of the dry cooling tower or air-conditioning condenser is as follows:
Hot water from industrial processes enters the cooling tower through pumps and pipes. This hot water flows through the copper coil (or reciprocating copper pipes). At this stage, indirect contact between weather and climate occurs: In this way, the outside air is sucked into the cooling tower by the fans in the coil's outer part. Then, this air collides with the surface of the hot fluid transfer tubes, and as a result of these continuous collisions, the fluid coming out of the dry cooling tower loses its heat to the dry temperature of the surrounding coil and cools down.
Cooling Tower Main Parts
Every cooling tower consists of four main parts. These are as follows:
fan stack (throat)
Louver (air shutter)
panel (wall)
pan
a column
Cooling Tower Coil
The cooling tower coil is one of the components of the closed-circuit cooling tower. These coils function similarly to the packing and nozzles in open-circuit cooling towers. The key difference is that the nozzles spray water, while coils in closed-circuit towers circulate water through pipes, and the heat exchange occurs indirectly through the surface of the metal pipes.
Closed-circuit cooling tower coils are classified into copper, steel, and galvanized categories based on the material used.
Cooling Tower Fan
The cooling tower fan is the main component of a cooling tower, significantly influencing its efficiency. These fans circulate vast amounts of air through the device, requiring maximum efficiency and minimal vibration for optimal performance. Factors such as blade width, impeller diameter, and fan rotation speed contribute to varying airflow in different fan types. Like other AC fans, cooling tower fans can be categorized into centrifugal and axial types, most commonly used in round and square cooling towers.
Cooling Tower Drift Eliminator
An eliminator or drip catcher is typically installed above the nozzles to minimize the number of water droplets drifting from the top of the cooling tower. These are commonly made of PVC or PP materials. PVC eliminators often feature a honeycomb design, while PP eliminators use a V-bar design, reducing water loss to less than 0.02% of the tower's circulating water.
Cooling Tower Packing
The packing inside the cooling tower must be selected based on the appropriate design and material. Typically, cooling tower packings are made from 400-micron-thick, antibacterial pharmaceutical grade PVC or splash/random splash packings made from polypropylene (PP), depending on the buyer's preference and order.
Cooling Tower Maintenance and Care
Knowing and understanding the various types and their benefits and disadvantages is crucial for maintaining a cooling tower, as well as the following factors:
To protect the tower body against harmful ultraviolet rays, as cooling towers are often situated in open environments and exposed to direct sunlight, applying a suitable Nopitel Clickal Gel (NPG) coating is essential.
The main structural elements and secondary parts (screws, nuts, etc.) should be made from stainless steel or galvanized iron, as internal cooling tower components are in constant contact with water.
Considering that the water temperature reduction in the cooling tower is an evaporative process and is accompanied by the evaporation of a significant volume of water, the degree of hardness and The quality of water in the cooling tower, especially in the open circuit cooling towers, is very important. Failure to maintain and control water hardness in standard conditions (less than 50PPM) causes sedimentation and adhesion of water sediment to the packings inside the device and, in the long run, in addition to reducing the lifespan and efficiency of the device. It even causes the internal pipes of the chiller condenser or heat exchanger to clog, resulting in financial losses.
The necessity of using a stainless steel filter on the bottom of the cooling tower pan and the way the water coming out of the device and continuous visits to make sure that the meshes (holes) of the filter are not clogged due to the prevention of any blockage in the way of the cooling system pipes such as Condenser is a chiller.
To control and adjust the water hardness level of the cooling tower, in addition to the necessity of using resin hardeners in appropriate capacities or electromagnetic hardeners, the method of flushing or flushing should also be used to reduce the accumulation of hardness and water salts in the water. Used a cooling tower pan. Its method is that according to the cooling tower's capacity every 30 to 45 days, the facility's operator must completely drain the water and salts of the cooling tower pan from the lower part of the pan, and the new water is very hard. Replace the bottom one.
Tips to Increase the Lifespan of the Cooling Tower
Consider the following tips if you want a long-lasting cooling tower:
To increase the life of the electric motor and reduce the fan's noise when starting the cooling towers, ensure that the body and chassis of the tower are level, as well as the static and dynamic balance of the cooling tower fan.
When ordering high-capacity cooling towers, using a power transmission system with a gearbox belt is better.
Installing a ladder is mandatory for easy access to the upper part of the cooling tower, including the electric motor and its possible service and repairs (especially in high capacities).
In water-cooled air conditioning systems, the temperature of the water entering the cooling tower (from the water condensation chiller condenser) should be around 33 to 37 degrees Celsius, and the temperature of the water leaving the cooling tower to the water condensation chiller condenser (cooling water) should be around 28 to 32 degrees. Celsius. In other words, the temperature difference between the inlet and outlet water of the cooling tower in air conditioning systems will be around 4 to 6 degrees Celsius.
The New Generation of Cooling Towers
The new generation of cooling towers are cube-shaped and cross-flow type with the possibility of air suction from only two sides of the device. Using the new design and technology in the construction of cross-flow cubic cooling towers, the limitations and disadvantages of the old generation of cooling towers have been completely removed.
The most important advantages of the new generation of cubic crossflow cooling towers are as follows:
The ventilation fan's sound has been reduced significantly by using special aluminum alloys and designing it with special angles.
Installation of the inspection valve for easy access to the cooling tower's interior to reduce the device's periodic services (in the case of the customer's order and specified in the purchase order invoice).
It does not occupy much space with the possibility of air suction only from its two sides, especially in high capacities, and the arrangement of new cubic cooling towers side by side without needing lateral distances from each other (need less installation space).
Significant savings in water and electricity consumption of the device.
Using new technology to evenly distribute water on the internal packings of the cooling tower by gravity method.
No need for a water dispenser and complete elimination of problems caused by it (such as clogging of nozzles and broken shafts and related financial losses).
Separation of capacity and construction of smaller cooling towers in the form of multi-cells in more suitable capacities by having several electric motors and smaller propellers and eliminating the complete vibration of the device
The Function of the Cooling Tower Multi-Stage Thermostat
By using a multi-stage thermostat and installing it on the water pipe coming out of the cooling tower pan to the chiller condenser, it is possible to reduce the water temperature by changing the speed of the electric motor of the cooling tower fan according to the command sent to the tower inverter, based on the set temperatures of the gradual thermostat. Controlled the output from the cooling tower (input to the condenser).
Suppose the intelligent control system is not installed. In that case, it is necessary to install at least one thermostat with the possibility of turning off and on the fan motor of the cooling towers for the times when the weather is milder, on the outlet water pipe from the cooling towers to the collector of the cooling towers pumps. To be able to have more control over the temperature of the water coming out of the cooling tower.
If you need advice regarding the selection, calculation, and purchase of household and industrial cooling towers, you can contact the sales expert of DamaTajhiz HVAC. As the first and most reliable sales collection of all construction and air conditioning equipment in Iran and the Middle East countries, the technical information and guaranteed prices of all types of cooling towers in various capacities have been presented in the specialized collection of Damatajhiz for intelligent and optimal review, selection and purchase.
At any stage of reading this article, you can contact our experts in the specialized collection of heating equipment; in addition to getting the necessary advice, you can experience a satisfactory purchase from this dynamic collection.
Replacement of the Old Cooling Towers
Suppose you plan to replace your old, worn-out cooling tower with a new fiberglass one. At the same time, you check the capacity, the volume of circulating water, dimensions of the tower, chassis, and the possibility of installation in the place of the old cooling tower. In that case, you might as well want to pay attention to the flow rate of the circulating water pump of the new tower! Especially when replacing a galvanized or Marley with a fiberglass cooling tower.
Here are some extra key points to consider when replacing your cooking tower:
The thickness of the fiberglass body
An anti-UV coating
Galvanized bolts and body
Having a Super Blade Fan
The type and amount of the packing
The strength of the stands
The quality of the electromotor fan
Quality of the stairs or the ladder
Water Softener & Filtration System in Cooling Towers
Various microorganisms present in running water can grow and multiply in the cooling tower water. As they adhere to the pipe and other components of the device, these microorganisms can cause corrosion and damage, ultimately diminishing the system's efficiency. Furthermore, bacteria and algae in the cooling tower water can corrode parts and lead to deposits.
Calcium and magnesium hardness are the primary factors contributing to deposits in cooling tower and chiller condenser components. These deposits obstruct proper heat exchange and decrease the efficiency of the equipment by creating a hard surface. Contaminations, such as airborne dust, can also cause deposit formation in the cooling tower and chiller. When these materials enter the cooling tower and become damp, they create a mud-like layer in the pipes and other components, significantly reducing the system's efficiency.
A water softener and filtration effectively prevent deposit formation on various parts and surfaces of the cooling tower and chiller. Additionally, incorporating appropriate anti-scaling agents for the water aids in preventing deposit formation and maintaining the device's efficiency. Using water softeners and filtrations directly correlates with reducing repair costs and increasing the cooling system's efficiency. To prevent deposit and corrosion of pipes and components (also for related equipment like chillers). It is advisable to add appropriate anti-scaling agents and use filters compatible with the cooling tower.
Estimating Water Compensation of the Cooling Towers
In normal conditions, the approximate water consumption for all types of cooling processes in cooling towers can be considered as 0.2 to 0.3 liters per minute for each nominal ton of tower capacity. However, it's important to note that water consumption in cooling towers depends on factors such as relative humidity, ambient air temperature, and the temperature difference between the incoming water and ambient air.
When the cooling tower is in the refrigeration circuit, the amount of compensation water can be calculated based on the type of chiller compressors, according to the following estimates:
For chillers with screw compressors: 4 GMP/100 ton
For chillers with centrifugal compressors: 4 GMP /100 ton
For chillers with reciprocating compressors: 4 GMP /100 ton
For absorption chillers: 8 GMP /100 ton
At DamaTajhiz HVAC team, we offer various cooling towers at competitive prices, ensuring you can find the perfect solution for your needs. Our comprehensive technical specifications provide all the information you need to make an informed decision. We pride ourselves on offering original warranties and fast nationwide delivery for all our products. With DamaTajhiz, you can easily choose the ideal cooling tower for your requirements.
Cooling Tower Industrial Applications
Using cooling towers in the industry is an effective way to remove unwanted heat from molds, processes, or heat exchange of one fluid with another. In this operation, hot water from industrial equipment or any other heat source enters the open circuit or closed circuit cooling tower and spreads evenly on top of it. As the water flows down the cooling tower, the flowing water is evenly sprayed on the packings (in open circuit towers) and on the coil (in closed circuit towers) to increase the contact of water with the air.
Therefore, heat transfer and reduction of water temperature in the tower are done through the process of water evaporation. At the same time as the water evaporates, the heat is taken from the water. Finally, after its temperature decreases, the water is collected in the lower part of the cooling tower pan. Then cool water is pumped towards the desired devices in the direction of the product production process to prevent the temperature of these devices from rising too much, And this cycle is constantly repeated.
As mentioned before, one of the most important points regarding reducing the water temperature of industrial processes by using open-circuit cooling towers is to pay attention to the temperature of the water exiting the process or the water temperature that we want through the method of evaporative heat transfer by the cooling tower.
The use of industrial cooling towers to reduce the temperature of circulating water in product process operations in all kinds of industrial factories, such as glass and ceramic production, wood and paper industries, pharmaceutical and medical industries, food industries (dairy and oil production), petrochemicals, etc. It is very widely used.
How Do Industrial Cooling Towers Work?
Industrial cooling towers efficiently remove excess heat from one fluid to another using water. In this process, hot water from industrial equipment or other heat sources enters the open or closed-circuit cooling tower and spreads evenly on top. As the water flows down the tower, it covers a large surface area, increasing air-water contact and promoting heat transfer through evaporation. As water evaporates, it loses heat. Finally, after the temperature has been reduced, the water flows into the tower pan at the bottom. The cooled water returns to the primary heat source, and the cycle repeats.
Factors to Consider when Using an Open-Circuit Cooling Tower in Industrial Processes
If you want to use the open circuit cooling tower and related packings to cool the hot water of industrial processes, install a water pool next to the cooling tower device so that the hot water enters the pool before entering the device, which evaporates during the water evaporation process. It is necessary to reduce its temperature to some extent and make it suitable for entering the cooling tower.
A very important point in industrial cooling towers is the relatively high temperature of the output water from production processes. According to the quality and material of the open circuit cooling tower packings, these packings are usually resistant to a temperature of 55 and a maximum of 57 degrees Celsius in the best conditions, and for higher temperatures, other solutions should be used as an alternative.
Tips for Transporting and Installing Cooling Towers
When transporting and installing cooling towers, consider the following:
Diameter of the Cooling Tower
Suppose the diameter of the fiberglass cooling tower you purchased exceeds 220 cm. Transporting the tower separately to the project site is advisable to prevent damage during transportation. The final assembly of cooling towers with diameters greater than 220 cm would be completed on-site with an additional fee.
The Stand of the Cooling Tower
The stand of the cooling towers is designed and constructed according to the exact weight and dimensions of the tower to ensure that it can support the tower's weight by the building's structure and avoid any issues related to the architectural appearance of the building. If a crane cannot move the integrated tower at the project site, refrain from ordering the assembled cooling tower.
The Location of the Cooling Tower
The installation location of the cooling towers must have no obstacles, ensuring the free flow of fresh air into the tower. Additionally, when multiple towers are used nearby, take measures to prevent the air exiting one tower from directly entering another, as this may reduce the device's efficiency. Once the appropriate capacity is selected and placed outdoors with unobstructed air flow, achieving optimal efficiency should not be an issue.
However, if the cooling tower is installed inside a building or enclosed by walls, consider the following:
There must be ample, unobstructed space around the tower to allow fresh air to reach the cooling tower.
The humid air exiting the cooling tower must be discharged to prevent it from returning and recirculating within the tower. Recirculation of such air increases the wet temperature of the air entering the tower, causing the water in the system circulation at the exit from the cooling tower to remain warm.
When multiple towers are installed nearby, preventing air recirculation is especially important.
The installation location of the cooling tower is determined by various factors, including the sound intensity at a 10-meter distance, the structural strength of the location, additional equipment costs, and architectural considerations.
Due to the importance of fan balance in the performance of the cooling tower and its direct relationship with the lifespan of the fan and electromotor, to maintain the dynamic balance of the air circulation fan, pay attention that all types of cooling towers should be installed in a completely horizontal and level position at the installation site.
Cooling Towers Clogging Causes
Fouling in cooling towers occurs due to solutes in the water. The primary cause of deposits in cooling tower systems is calcium bicarbonate. Cooling towers operate based on evaporation, which facilitates the cooling process. As a result, pure water is removed from the cooling tower and added to the residual water solutes. Over time, this increases the hardness of the water in the cooling towers.
Generally, reducing the water's hardness can decrease the overall deposit, allowing for cleaning without opening the packing by only increasing water pressure in the system. Also, to balance the hardness of the water in the cooling tower, the water in the pan should be drained regularly. Blowdown in the cooling tower drains the pan water to a certain amount based on the volume of water in the system.
How to Descale a Cooling Tower
Here are two quick steps to clean and remove scales from the cooling tower and increase its efficiency:
Open the body of the cooling tower and remove the packing(s)
Clean the packing with some gentle tab of your hand
Factors to Consider When Buying Square or Round Cooling Towers
When looking to buy a cooling tower, consider the following factors:
Capacity and Dimensions: Ensure the cooling tower is suitable for the space where it will be used, as it comes in various types, capacities, and uses.
Water Make-Up Requirements: This will help determine your project's appropriate model and capacity at the right price.
Characteristics, brand, and type of the cooling tower: Research these factors to make an informed decision.
Fiberglass, Galvanized, and Concrete Cooling Tower Price
The price of a fiberglass cooling tower varies depending on its type, capacity, and brand. To simplify the process of selecting and purchasing a cooling tower, it's essential first to determine the necessary tower capacity.
All cooling towers featured on the DamaTajhiz website have product identifiers and appropriate pricing. Any discounts sought by customers have already been included in these prices.
Dear users:
Reading the stated information above to obtain additional information to purchase the types of cooling towers. You can also contact the experts of the AC equipment by dialing one of the extension numbers 117-119-120-126-317 to get advice or just to ask your questions.
Dear users, while thanking you for the trust you put in the technical opinions of air conditioning sales experts of DamaTajhiz, it should be noted that the choice of the desired product brand based on history, brand strength, service, and product price is ultimately determined by the buyer. But in the field of cooling towers, most users and buyers choose and buy best-selling brands such as Ventilation, Saran, DamaTajhiz, Saravel, and G Plus due to their quality, price, and after-sales service.
Also, since Damatajhiz HVAC is one of the main groups specializing in heating equipment, it is the first and most viewed authority for selling air conditioning equipment and an official member of the heating and air conditioning equipment sellers' union. Therefore, it is now safe to say that we provide all kinds of cooling towers in the Middle East region. Therefore, if you are from the same country in the region and you need a cooling tower, please place your order with our sales experts team. Product warranty and a reasonable price are included.
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