Water piping arrangement of the cooling tower

The cooling of the solution in the absorber and the distillation of the refrigerant in the chiller condenser make the necessity of using a cooling tower and, naturally, it's piping inevitable; But if there is access to other sources to provide cool water, they can be used by considering some measures. The water of deep wells, which have a constant temperature throughout the year, as well as the running water of the river, are among these.

Temperature and water flow control in cooling towers

The temperature and water flow rate of the cooling tower have a significant effect on the cooling capacity of the chiller. Therefore, it is extremely important to pay attention to the quality and quantity of the cooling tower water and its precise control according to the temperature and flow rate of the heating fluid (steam or hot water). There are various ways to control the water temperature of the cooling tower, the simplest of which is to use a thermostat to turn the cooling tower fans on and off. In this method, the thermostat sensor measures the temperature of the cooling water entering the chiller, and If the water temperature is sufficient, the fan will be turned off.

Some galvanized cooling towers have several centrifugal fans, in these cases, multi-stage thermostats can turn the fans off and on in the same order in stages under the influence of different set temperatures.

In towers that have a large axial flow fan, it is possible to reduce or increase the speed of the fan with the help of a speed drive, or even turn it off or on.
In high-capacity towers that have only one cooling fan, controlling the fan by switching it on and off may cause problems. These problems include the rapid increase in water temperature and the need to start the fan in a short period of time. In this case, the duration of the fan shutdown is reduced and the duration of its operation is increased. To solve this problem, the motorized three-way valve and bypass of the water flow are used.

In this method, a motorized three-way valve with a bypass is used in the water inlet pipe of the tower, and a part of the water goes into the return circuit and adjusts the temperature of the water entering the chiller.
Sometimes it is necessary to use both methods of fan control and water temperature control by means of a three-way valve in combination.
Also, another method is to use the speed drive in the way of the cooling tower pumps and change the speed of the water electro pumps in the tower.

Calculation of the size of the pipes and tower water circulation pump

Calculation of the size and diameter of the pipes, as well as the head (pressure) and flow rate (flow) of circulating water in cooling towers, only by engineers and facility experts based on various parameters such as flow rate and required circulating water flow (GPM), head Cooling tower water flow circulator pump, pressure drop in the pipes and connections of the water flow path to the tower, water flow pressure drop in the condenser or absorber pipes and finally the required pressure when spraying water on the packings according to engineering diagrams and tables become

According to ARI 560, the water flow rate of the cooling tower for single-effect absorption chillers is 3.6 gallons per minute per ton of refrigeration, and this amount for double-effect absorption chillers and a direct flame is equivalent to 4 gallons per minute per ton of refrigeration; But in any case, it is better to calculate the required flow rate exactly based on the difference between the inlet and outlet temperatures of the cooling tower and the cooling capacity of the chiller. To determine the pump pressure, it is enough to add the return length and add the equivalent length of its connections. based on the drop of 2.5 feet per 100 feet, multiply by 2.5 and divide by 100, and then add the height of the tower from the pan to the sprinkler and add the pressure drop caused by the condenser and absorber with it. To determine the length Equivalent to the connections and the return line, we can consider three times the length of the line (LS).
So we will have:

Evaporation of water in the cooling tower regularly increases the concentration of the remaining water in the tower pan and increases the impurities in it, and increasing the hardness of the circulating water will cause sedimentation in the condenser and absorber tubes. Depositing in the pipes while eroding them also reduces heat transfer. Therefore, it is necessary that the water in the cooling tower is regularly drained and hardened water takes its place as compensation water. This process can be done manually or It should be done automatically. For this purpose, the valve and the pipe under the drain should be installed in the pan or water suction pipe of the cooling tower.

Necessary measures to maintain the cooling tower after installation

As you know, the presence of sediment and mud causes the accumulation of microbes and accelerates their growth. For this reason, a regular monthly inspection of the cooling tower and cleaning of waste materials that accelerate this growth will prevent this problem. Parts such as plates or packings and tower basins are very suitable environments for the formation of these sediments and microbes. For this reason, cleaning and disinfection of these parts are of high priority.

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final word

In the reference and specialized website of DamaTajhiz, the technical information of dozens of models of cooling towers, from reputable brands with original warranties, has been presented in order for you, dear ones, to enjoy the good feeling of an optimal and smart purchase. If you need advice and choose a tower, you can contact the air conditioning equipment experts in this complex during office hours.

Related articles

In order to get more information, it is recommended to read the articles related to the arrangement and piping of cooling tower water.

• How to choose the best cooling tower
• Methods and principles of cooling tower maintenance
• Everything about industrial chiller
• Fiberglass cooling tower

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