History of cooling tower تاریخچه برج خنک کننده

History of cooling tower

Cooling Tower (Cooling Tower) in general, the term cooling tower has had many applications in the global industry and throughout history. The first works of design of cooling towers or cooling towers can be seen in ancient Egypt in order to cool the water used for bathing and by spraying the free flow of water stream on the man-made rocks. After many years, humans used this device in many cases without knowing the technical knowledge and design of the cooling tower and even without knowing the name and design knowledge of the cooling tower.

After the European Industrial Revolution and the growth of industry in the world, the direct use of water from rivers, streams, lakes and wells to cool industrial devices expanded. For years, the method of direct use of natural resource water to cool industrial equipment was the first choice of large industrial plants. After several decades and the increasing reduction of natural resources, many factories due to lack of water resources or environmental effects of excessive water consumption and also increasing pollution of water resources to find a suitable solution to return water consumption from natural resources and combat The above problems (cooling tower), acted.

The first cooling tower, called Cooling Water Builder, was placed in the way of river water, and in this work cycle, in order to return the hot water used by rivers in industrial factories, it was put into orbit. Early cooling towers often had very large concrete structures. Concrete cooling towers have been used since the European Industrial Revolution. Today, cooling towers with concrete structures are generally used in hyperbolic and cubic shapes in the power plant and petrochemical industries in the country. This model of cooling tower is also called power plant cooling tower.

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The next generation of cooling towers over time is the wooden cooling tower. The wooden cooling tower was generally considered a suitable alternative to the concrete cooling tower in smaller scales due to its faster construction and lower weight. In the wooden cooling tower, the first type of cooling tower packing with wooden structure was used.

After a while, the wooden cooling tower was completely removed from the industrial application circuit due to insufficient resistance to rot and sunburn, as well as due to water absorption and deformation over time in its structure, and galvanized cooling tower or Galvanized cooling tower with centrifugal aeration system replaced wooden cooling tower.

Galvanized cooling tower was a good alternative to wooden cooling tower due to its higher resistance to decay, no deformation and more stable structure. Eventually, the galvanized cooling towers were also reactive to water, and the effects of rust, rot, and the growth of microorganisms (sludge) were quickly seen. Galvanized cooling tower repairs, or so-called metal cooling towers, were extremely difficult due to rusting connections and lack of easy access to the internal components of the cooling tower.

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For the above reasons, the latest generation of cooling towers, called fiberglass cooling towers, have completely replaced concrete, wood and galvanized cooling towers. Fiberglass cooling tower A type of cooling tower with a composite or fiberglass structure has numerous advantages over its previous models, which we will mention briefly.

1- Lightness and portability of fiberglass cooling tower

2. Easy maintenance of fiberglass cooling towers compared to various types of galvanized cooling towers and concrete cooling towers

3. No penetration of sunlight (lack of absorption of solar radiation due to the apparent white color of the body) into the fiberglass cooling tower

4- No reaction with water or in other words no rot and rust of the fiberglass body of the cooling tower against water

5. Lack of growth of bacteria, microorganisms and sludge in the pan of fiberglass cooling tower

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Fiberglass Cooling Tower is an all-composite body made of suitable fibers and resins. Fiberglass cooling tower is produced and designed today in various types of open circuit cooling towers and closed circuit cooling towers. The new generation of cooling towers with the aim of reducing the compensatory water consumption of the cooling tower, reducing the amount of sediment in the cooling tower and in general with the aim of optimizing the energy consumption of the cooling tower, called hybrid cooling tower and evaporative cooling tower or evaporative condensers. evaporative condenser) has replaced a variety of open circuit cooling towers.

In a general statement, it can be said that all industrial and non-industrial equipments used by human beings have undergone many changes over time, and the cooling tower, like many other industrial equipments, has undergone many changes and transformations. Cooling tower On the one hand, in terms of the quality of materials used in the production of this device, and on the other hand, in the overall design of the cooling tower, general changes can be seen.

In order to improve the quality of its products as much as possible, especially the cooling tower, Damagostar Company intends to take steps with the latest technical knowledge of the world and by using the unremitting efforts of its engineers. The cooling tower of Damagester company is produced in different types and in different application directions in accordance with the up-to-date knowledge of the world and is in the service of the country's industry.

cooling tower برج خنک کننده

cooling tower

Cooling tower or in the modification of the cooling tower is a water cooling machine, which is also called "water cooling tower" . A cooling tower is a refrigeration machine that is typically used to reduce water temperature to a certain range. The reduction of water temperature in the cooling tower is naturally dependent on the temperature conditions of the installation environment. This cooling machine ( cooling tower) absorbs the heat of the machines by water and directs it to the outside environment.

It is interesting to know that the heat absorbed by the industrial equipment in the internal mechanism of the cooling tower is transferred to the outside by dry air. In other words, a cooling tower is a type of energy exchanger between climates, which is actually called a heat exchanger (heat exchanger). In fact, this refrigeration source exchanges heat energy by making contact and contact between hot water and ambient air. Heat is exchanged from hot water to cool air, which reduces the water temperature.

Why do we use a cooling tower ??

The question may be, why do we use a cooling tower? In response, it should be stated that the cooling tower is complementary to every device and machine that is used in a specific direction. In fact, it should be said that every industrial machine and any device that is used heats up after a while. Air or water is used to cool all industrial machines such as chillers, boilers, etc. The water that absorbs the heat of an industrial machine is heated and needs a device to reduce its temperature again. In other words, the cooling tower (also known as the cooling tower) is responsible for re-circulating water to cool other devices.

*** Take a closer look at the operation of the cooling tower

The cold water produced in the cooling tower re-absorbs the extra energy of the equipment and frequently transfers it to the air. This process is an iterative cycle that keeps the operating temperature of industrial machinery constant . Water cooling tower or cooling tower with continuous production of cold water can take the heat of the chiller, boiler or induction furnace.

Permanent reduction of machine temperature and heat absorption of this equipment is required for system stability. Lack of cold water circulation will increase the temperature of these equipments and their inefficiency. Therefore, the need to use a cooling tower will stabilize the "system" with the highest efficiency. This system may be the air conditioning cycle of a residential, office or commercial building, or the production process of a particular product by an industrial machine.

Method of calculating the power or capacity of the cooling tower

The ability of a cooling tower to dissipate heat energy from a water fluid and transfer it to air is called refrigeration capacity or cooling tower capacity . The higher the cooling capacity of the cooling tower, the more water it will be able to bring to the desired temperature at a given time. The type of cooling fluid, the amount of fluid volume in rotation and the difference between the inlet and outlet temperatures of the fluid in the cooling tower are the main factors determining the capacity. The volumetric rate of circulating water is also called water flow rate. Of course, the ambient temperature factor, hot and cold water temperature are other factors involved in the design conditions. The difference between the inlet and outlet temperatures of the fluid is called the deltati or range.

Determining characteristics of cooling tower capacity

• Circulating fluid flow rate (nominal fluid flow)

• Type of coolant and determination of specific heating capacity

• Fluid inlet and outlet temperature (outlet temperature depending on the design environment)

• Design impact factor in calculating the nominal capacity and separating it from the actual power

Methods of calculating the cooling capacity of the cooling tower

•  Thermodynamic equations governing design conditions (q = m * c * delta T)

• Calculation based on the capacity and type of chiller only in the use of chiller cooling

• Use of cooling software cooling capacity calculation software

 More information in the cooling tower calculations section

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What is the meaning of refrigeration in the cooling tower?

You must have heard many times that the capacity of the tower is equal to 100 tons or the capacity of a specific model of chiller is equal to 200 tons. The word "ton" in the cooling tower and chiller means the same cooling capacity of the device in cooling water. The word body in this engineering term is abbreviated to "refrigeration body" or "cold body". Cooling is one of the heat transfer units and a measure of the power of refrigeration devices. The refrigeration ton thermodynamic unit (RT) is equivalent to units such as KW and BTU / H. Each ton of refrigerant is equal to 3.51 kW and is equivalent to 12,000 BTU per hour.

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What is the use of a cooling tower?

1- In order to cool various industrial devices

Most industrial machines, such as furnaces, boilers, and turbines, generate some extra heat in their duty cycle. The function of the industrial cooling tower in the cycle of these machines and equipment is to absorb and dissipate the excess heat generated. Gas turbines in refineries, air compressors in power plants and boilers in industry are among the most important cooling equipment with cooling towers. The task of extracting this thermal energy is the responsibility of the air fluid. The use of other refrigeration machines such as chillers is also common in small and large industries. High costs in energy consumption, difficult maintenance of chillers, has made the industry welcome the cooling tower.

2- To cool the air conditioning chillers of buildings in summer

Most large buildings and towers, offices, banks and shopping malls have central air conditioning (HVAC). Concentration or absorption chillers are used in central cooling systems to cool the indoor air. The heat absorbed from a building area by the chiller increases the temperature of this refrigeration machine. Cooling tower is used in this application under the name of chiller cooling tower with the aim of adjusting the chiller temperature . The cooling tower generates cold water and directs it to the condenser, causing the temperature balance of this equipment. It should be noted that only chillers that have a water condenser use a cooling tower in their condenser circuit. Today, most compression chillers and all absorption chillers have a water condenser.

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Types of cooling towers

• Open Circuit Cooling Tower (Wet)

The open cooling tower reduces the water temperature by creating a direct contact exchange surface between air and water. In this cooling tower model, a percentage of water evaporates and enters the inlet air. This causes the surrounding air to become humid or saturated. For this reason, this model is also called the wet cooling tower cooling system . The water coming out of the nozzle or sprinkler starts to fall on the packings in contact with the air and the temperature decreases. Wet systems are also called open circuits because the water cycle takes place in an open cycle.

• Dry closed circuit cooling tower

In this cooling tower model, water is cooled in a completely closed cycle in contact with the dry air of the environment. Hence, this type of refrigeration system is also called dry cooling tower . This type of cooling tower is subject to the noticeable temperature of the installation place (ambient temperature) due to direct contact with the dry air of the environment. Dry or closed cooling tower has heat transfer surfaces such as pipe and fan networks. Water passes through these networks in contact with the air created by the fan or impeller.

• Hybrid cooling tower (hybrid)

The new generation of evaporative refrigeration equipment, which is a combination of open and closed cooling tower, is called hybrid cooling tower . The main stream of water fluid is passed through the thermal penetration surfaces of the coil by a secondary spray stream. In this contact, heat is transferred by penetration and conduction from the hot water of the coil to the cold water of the spray circuit. The big advantage of this cooling tower model is the reduction of water temperature to close to the humid ambient temperature. At the same time, this refrigeration system does not have any sedimentation and evaporation.

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Types of cooling towers based on the type of inlet air flow

• Opposite flow cooling tower or counter flow

Canterflow cooling tower has air inlet from all sides of the device in the upper part of the pan and the lower part of the packings. The direction of the incoming air flow to the cooling tower is the opposite flow in the opposite direction to the spray water flow from the nozzle. In this model, air enters from the lower louvers and exits from the upper part of the fan oven. The efficiency of this cooling tower model is very suitable for hot and dry environments. They are widely used in cities such as Yazd, Shiraz, Mashhad, Tehran, Arak and Isfahan where the relative humidity is low. Counterflow systems are more efficient than crossover systems. Of course, the use of these systems in humid and humid areas has little efficiency.

• Cross-flow cooling tower or cross-flow

Cross-flow cooling tower or vertical flow has two main air inlets on both sides. The air entering this section perpendicular to the water flow causes this fluid to cool. Cross-flow cooling tower performs well in humid areas due to fresh air contact throughout the Beijing area. In the northern and southern regions of our beloved country, which due to its proximity to the sea, the humidity of the environment where the cooling tower is installed is high. In such climatic zones, cross-flow or Abara cooling towers are used. Cities such as Ahvaz, Mahshahr, Bushehr, Rasht, Gorgan, etc. are very suitable for using this device. This model was first conceived by the Japanese company Abara. For this reason, such refrigeration systems are also called Abara cooling towers.