What is the work of cooling tower?
In a simple answer to the first question, we must say that the work of the cooling tower is to cool the water and provide it to remove the waste heat of other machines. Machines such as absorption and compression chillers, steam boilers, plastic injection machines, induction furnaces, distillation boilers, gas turbines are considered the most important equipments that benefit from the cooling tower next to them.
In reality, the cooling tower is a source of cold water to remove the excess heat produced by the above equipment. Today, cooling towers are widely used in steel industries, petrochemicals, refineries, power distribution plants and other small industries. The importance of using the cooling tower is equal to the function of the equipment itself, because the absence of the cooling tower will cause the entire system to fail. If you want to know what the cooling tower works, stay with us.
What is the use of cooling tower in today's industry?
Every large and small factory today has an urgent need to use a device called a cooling tower because it can transfer the excess heat of its equipment to the outside. Sugar factories, paste factories, plastic injection workshops, steel companies and power plants are among the most important consumers of this device. It should be noted that there are few industries that have not benefited from the presence of a cooling tower in their collection.
The growth and development of the cooling tower production industry has made significant progress due to this issue. Today, cooling towers are placed outside and in the open air, and the main reason for this is the way the cooling tower works. A cooling tower cools water by absorbing free air and creating a percentage of evaporation, which we will explain in detail how it works.
How does the cooling tower cool?
Many cooling machines today are based on the science of thermodynamics and heat transfer. The cooling tower is one of the cooling machines that achieves its work by using the evaporation action and the combination of heat transfer and mass transfer. Now, depending on the climatic conditions of the installation, it can have a concrete, metal or fiberglass body. In some cases, it can be seen that in order to reduce the amount of water consumption, the closed-circuit type of this equipment is used.
Function of Cooling Tower
In fact, in simple terms, regardless of the type of cooling tower or body type, the main task of the cooling tower is to cool the water by constantly contacting it with the open air and creating a small percentage of evaporation. Of course, it should be noted that the efficiency of cooling towers will be different in different regions. For example, in a city like Isfahan, which has a relatively mild climate, the work of a cooling tower will be easier than in a city like Bushehr. Bushehr is a city with a humid climate and therefore a cooling tower cannot do its job well.
How much is the water outlet temperature in the cooling tower?
Cold water coming out of a cooling tower always has a temperature higher than the temperature of the air in that environment. Sharjah air temperature or so-called "bubble temperature" is a determining factor in cold water temperature parameter. For different cities, the temperature of bubble water or wet bulb varies from 15 to 35 degrees. For Sharjah environments with humidity above 70%, the temperature of the wet bulb is higher and the cooling tower will be very limited in cooling the water in the summer.
Of course, the declared bubble temperature will be examined only in the summer season and in the worst climatic conditions. Another thing to mention is that a cooling tower will not be able to reduce the water exactly to the wet ambient temperature. The cold water cooled in this equipment is always 3 to 5 degrees higher than the ambient temperature, and the temperature drop created in all types of cooling towers is measured by the stated law.
How is the capacity of cooling towers calculated?
The thermal power in absorbing the heat of industrial machines in the condenser section by the cooling tower is called refrigeration capacity. The capacity of a cooling tower is expressed in terms of refrigeration ton or RT. The cooling tower capacity is sometimes expressed in units such as BTU/H and KW. Regardless of the calculation unit in expressing the cooling capacity, and more importantly, the way to calculate the cooling tower capacity is of great importance. To calculate the refrigerating capacity of the cooling tower, parameters such as circulating water flow rate, inlet and outlet temperature and even wet bulb temperature are used.
In order to calculate the capacity, we must determine the amount of heat that must be transferred from the water to the outside air by a certain time. Using an engineering consulting company to accurately determine the cooling tower capacity is the best option available. Today, many cooling tower manufacturing companies have provided their dear employers with the use of engineering staff to determine the value of this important parameter. The capacity of production cooling towers available today will vary from 20 tons of refrigeration to 15 thousand tons of refrigeration, which will be designed depending on the volume of circulating water and the difference in water temperature.
Introduction to the types of cooling tower in terms of performance type
1- Open circuit cooling tower: One of the most commonly used types of cooling tower is the open circuit or wet type (wet tower), which is installed in two cubic and conical shapes. This model, with uniform performance in different seasons of summer and winter, makes the water cooler by direct connection of hot water with dry air. The water is sprayed by the spray nozzles on the cooling bags (packings) and the air passes through the packings and absorbs the heat of the water and transfers it to the outside.
2-Closed cooling tower: Another type of cooling tower is the closed cooling tower, which is divided into dry and hybrid depending on the type of efficiency. Dry towers reduce the temperature of this fluid by totally indirect contact of air with the flow of hot water in findar coils. Hybrid cooling towers also have a similar function, and of course, by spraying a secondary cycle of water, they cool this hot fluid and practically do their duty with a double function.
CCTV cooling tower
Where is the CCTV or CCTV Cooling Tower?
Certainly, the answer to the above question will greatly help to choose a cooling tower in an industrial unit. Naturally, the cooling tower always evaporates a percentage of water (3 to 5%) for its operation. In many regions of the country, it is difficult and impossible to supply this amount of water, especially in refrigeration capacities above 100 tons. In order to solve this problem, many industrial factories use the closed cycle in cooling the water required for their devices. So, the first place to use a closed-circuit cooling tower is when there is no compensatory water supply for cooling tower consumption.
Another condition that you will definitely encounter in the performance of the cooling tower is the issue of sedimentation of this equipment in the open circuit type. Water circulating in a cooling source such as a cooling tower will always face an increase in the amount of salts due to constant evaporation. Increasing the amount of water will cause clogging in the condensers, the pipe path and even the tower itself.
The discussion of descaling from the condenser of industrial equipment as well as the repairs resulting from it, which will sometimes cause the entire system to fail, is very important. Many industrial units are forced to spend more money on closed-circuit cooling towers in order to avoid the problem of sedimentation. Well, in the end, if we really don't care about the amount of compensation water supply or sedimentation, it is undoubtedly recommended to use the open circuit type.
common problems in cooling towers
1- Clogging deposits of packings, shower nozzles, water distribution pipes and various internal parts of the cooling tower in contact with water
2- Freezing of the cold water storage pan in winter due to a noticeable decrease in ambient temperature < /p>
3-Difficulty of providing compensatory water in dry and desert areas, which is very high in Iran today. p>
What are the solutions to solve problems in cooling towers today?
Well, we got to the point and we have to say that with the advancement of engineering knowledge, most of the stated shortcomings have been eliminated. The sciences of mechanical engineering, chemistry and metallurgy have solved most of the stated problems and provided solutions for each of them. For example, to prevent water from freezing in a water storage basin, a smart antifreeze system including a heater and thermostat is used. The design of anti-clog sprinklers, the use of polypropylene (plastic) packings, and even the design of the closed-circuit cooling tower have solved these issues. The failure of ventilation parts has been solved to a great extent by using dehumidifiers and reducing the amount of moisture around these parts.