Design and construction of evaporative and hybrid cooling towers
What is a cooling tower?
A cooling tower is a device that takes unusable heat and excess water in refrigeration air conditioning systems or industrial devices and transfers it to atmospheric air.
The difference between cooling tower and condenser?
Although closed circuit cooling towers like evaporative condensers use the evaporative cooling process to remove heat, none of the closed circuit cooling towers condense refrigerant gas or water vapor; Rather, they simply reduce the temperature of the liquid water. Therefore, the purpose of using these two devices is fundamentally different from each other.
Methods of heat transfer in the cooling system
CCTV system
Open circuit cooling tower
Hybrid models
Closed circuit cooling tower
The reason why this type of cooling tower is called a closed circuit is that the hot water gives its heat to the atmosphere in a closed path without direct contact with the air, and because no part of the hot water evaporates in it, it is called a dry tower. Called. Therefore, in this type of cooling towers, we will not see any water consumption and there is no need to inject alternative water in the circuit of this device.
Open circuit cooling tower
The reason why it is called an open circuit is that the hot water that is pumped to the tower for cooling flows in an open space inside the tower and comes into direct contact with the atmospheric air to give its heat to the atmospheric air and because When the hot water meets the air, a part of the water evaporates, it is also called an evaporative or wet tower. It is obvious that the cooling efficiency is high in this system, but because part of the water evaporates, replacement water must be injected into the system circuit, and there is water consumption in this type of cooling tower.
Hybrid cooling tower
In the design and construction of evaporative and hybrid cooling towers , the fluid moves through the copper coil. Then, water is distributed on the outer surface of the coil by the sprinkler heads. By this function, the water is cooled both wet and dry and exchanges heat with the air flow. The important point here is that whenever the ambient air is hot, water distribution is done on the copper coils. But at night or when the ambient air temperature cools down, the hybrid cooling tower operates only in dry mode.
The structure of the hybrid cooling tower is based on the two-way combined mechanism. This two-way mechanism includes “two series water paths” and “two parallel air flow paths”. In addition, the upper and lower parts of the hybrid cooling tower are related to dry and wet functions. Thus, the upper part of the cooling tower has finned tubes and is related to the dry operation of the device. Also, the lower part of the device also includes acne where the wet cooling function is performed.
Special type of evaporative and hybrid cooling tower design and construction, causes fluid leakage, all additional suctions and water evaporation to be reduced to the minimum possible. Perhaps it is because of this performance that the hybrid cooling tower is considered a subset of closed circuit models.
Advantages of hybrid cooling system
Prevent water evaporation and fluid loss
High efficiency water cooling
Can be used in workshops and large factories
Installing copper coils in the design (reducing water consumption)
Suitable for drought times and dry and desert cities of the country
Smooth flow of fluid. (due to the design of the device using large diameter pipes)
Suitable for use in large power plants and refineries. (In these applications, the hot water must be continuously cooled and returned to the industrial process).
Absence of any problems in the cooling tower water distribution system (unlike open circuit systems)
Evaporative cooling tower
In the design and construction of evaporative and hybrid cooling towersFirst, the water enters the basin through the inlet pipes. Then the water is transferred to the upper part of the cooling system by the pumps. In the upper part of the tower, sprinkler heads (nozzles) are designed to distribute water uniformly on the packing. Be careful that if the packings suffer from corrosion, decay, breakage, etc… or the nozzles do not pour water evenly on the packing, the device will suffer a drop in efficiency; And sediment will definitely be formed in it. In addition, you have to say goodbye to the great efficiency of the device for now!!
On the other hand, air is also sucked in by fans. As a result, with the uniform drop of water on the packings, a thin layer of water or very small drops of water will be created, which will have a wide contact surface with the air. And with the contact between water and air, heat exchange takes place and the water cools. Finally, the hot air is thrown out through the upper part of the cooling tower. And the cooled water is re-entered into the industrial cycle through return pipes.
