Cooling towers work by moving heat from one place—the building and its activities, for example—to another using water or coolant, which subsequently reacts with the air to release the heat outdoors. Depending on the operations, several heat transfer processes may be used. A facility owner can choose from a variety of heat transfer systems to see which one best suits their needs. Let’s examine these three different kinds of cooling tower heat transfer processes.
Cooling Tower Heat Transfer Systems
Heat Transfer in Wet Cooling
Large facilities frequently utilise wet cooling transfer mechanisms as one of the types of heat transfer in cooling towers. As heat moves to fill the medium and disperses, it is transferred into the water. As evaporation takes place, the water comes into direct contact with the air. As the air exits the tower and moves outdoors, some of the hot water and heat are mixed into it. The residual water that is pumped through the system is collected in a basin located at the base of the tower. We call this kind of heat-transfer application an open circuit system. Spreading out the water as much as possible when it comes into touch with the fill material is the primary advantage of this technique. It enables optimal heat transmission across a wide surface area, accelerating the process.
Mechanisms of Dry Cooling
Dry cooling towers, also known as closed recirculating systems, employ a heat-exchanging device, usually a tube or network of tubes filled with coolant, to absorb cooling water and discharge it into the atmosphere. Heat is transferred from the heated liquid inside the tubes to the colder air, causing cooling. The cooling water is never exposed to air, which is why the process is considered “dry”. As a result, the unit evaporatively loses relatively little water.
Heat Transfer for Fluid Cooling
Certain operations utilize both wet and dry cooling systems. Like a dry cooling system, the water and air are enclosed in coils in what is known as a closed circuit system. Heat is taken up by the water and then moves through the coil to make contact with the air. As the hot air exits the cooling tower and travels away from the operations, the heat is redistributed into the air. This system’s primary benefit is that it reduces the amount of contaminants that can enter the system by keeping dirty air from the outside from mixing with the water.
Heat Transfer Mechanism Types Simplified
Types of heat transfer in cooling towers are combined in enclosure cooling. The following are the main methods for cooling electrical enclosures:
- Conduction: For instance, conduction is the process by which heat produced inside an enclosure is transferred to the exterior.
- Convection: Convection is the process by which heat is transferred from a surface using a fluid. When air is heated, it naturally condenses, rises, and is replaced by colder air. By increasing the airflow with a fan, one may increase the quantity of convection.
- Radiation: It is the process by which electromagnetic radiation is used to radiate energy through the atmosphere. It works well for sources of high temperature, like the sun, but not as well at Earth’s surface temperatures.
- Evaporation: By absorbing the energy needed to evaporate a fluid, the latent heat of that fluid may be employed to transmit heat. By permitting the fluid to condense outside the cage, the heat that has been absorbed is released.
Relying on natural conduction, convection, and radiation is known as passive cooling. This technique works well for enclosures with good ventilation, a sizable surface area, and light loads. The enclosure temperature cannot be higher than the ambient air temperature. In high ambient temperatures, this approach is not appropriate for temperature-sensitive components.
Fans that enhance the airflow through the enclosure can be used to boost the efficacy of convection. Hot air is released at the top of the cage while cool air is absorbed into the bottom. Filters should be installed on fans to reduce the amount of dirt that enters and may damage components. The surrounding air temperature needs to be significantly lower than the maximum enclosure temperature to prevent overheating of the electrical components.
To Conclude
In the discussion of heat transfer mechanism in cooling towers, several factors are taken into consideration. Towers are often classified according to how they are constructed (package vs. field-erected). In other cases, we categorize towers based on the kind of airflow—forced vs natural draft. On the other hand, three primary kinds of tower types are based on heat transfer mechanisms: fluid cooling, wet cooling, and dry cooling. Businesses use cooling towers for a variety of purposes, both large and small. As such, you can assume that there is no “one-size-fits-all” mechanism here.
For a better understanding, contact Tower Tech today.
