How do cooling towers work

Water, which has been heated by an industrial process or in an air-conditioning condenser, is pumped to the cooling tower through pipes. As the water flows through the cooling tower, it is exposed to air, which is being pulled through the tower by the electric motor-driven fan. When the water and air meet, a small amount of water is evaporated, creating a cooling action.

The cooled water is then pumped back to the condenser or process equipment where it absorbs heat. It will then be pumped back to the cooling tower to be cooled once again. Cooling Tower Fundamentals provides a level of basic cooling tower knowledge and is a great resource for those wanting to learn more. In crossflow towers the water flows vertically through the fill while the air flows horizontally, across the flow of the falling water. Because of this, air does not have to pass through the distribution system, permitting the use of gravity flow hot water distribution basins mounted at the top of the unit above the fill.

Counterflow towers are designed so that air flows vertically upward, counter to the flow of falling water in the fill. Because of this vertical airflow, it is not possible to use the open, gravity-flow basins typical in crossflow designs.

Instead, counterflow towers use pressurized, pipe-type spray systems to spray water onto the top of the fill. Since air must be able to pass through the spray system, the pipes and nozzles must be farther apart so as not to restrict airflow. Factory-assembled towers FAP are built and shipped in as few sections as the mode of transportation will permit. A relatively small tower will ship essentially intact. A larger, multi-cell cooling tower is manufactured as modules at the factory, and shipped ready for final assembly.

Factory-assembled cooling towers can be crossflow or counterflow, induced draft or forced draft, depending on the application. While all applications are different, the factory-assembled Marley NC crossflow, induced draft tower is widely used for HVAC and light industrial applications.

Using a total system approach, every cooling tower and component is designed and engineered to work together as an integrated system for efficient performance and long life. The goal of a free cooling system is to save energy.

It repeats the loop over and over again to constantly cool down the heated equipment or condensers. There are many different types of cooling towers but the cooling tower working principles stay pretty much the same. What is Evaporative Cooling? Evaporative cooling is the process where warm water from an industrial process is pumped up to the top of the cooling tower where the water distribution system is.

The water then gets distributed by cooling tower nozzles to the wet deck. At the same time, air is being drawn through the air-inlet louvers forcing water to evaporate. Evaporation causes the heat to be removed from the make up water. The hot air naturally rises out of the tire. An HVAC cooling tower is used for disposing or rejecting heat from chillers. Air cooled chillers are less effecient than water cooled chillers due to rejection of heat from tower water near wet-bulb temperatures.

Tradional HVAC heating and cooling systems are used in schools, large office buildings, and hospital. On the other hand, Cooling towers are much larger than tradional HVAC systems and are used to remove heat from cooling tower water systems in petroleum refineries, plants, natural gas processing plants, petrochemical plants, and other industrial processes and facilites. Cooling towers are usually designed for specific purposes.

Not all cooling towers work for all applications or industrial processes. Knowledge center. Types Cooling towers can be divided into types in different ways: based on the fan type, shape, water flow or efficiency, cooling water composition The basic cooling tower classification tends to be based on the following criteria: Natural or mechanical draft Induced or forced draft Open, closed or hybrid cooling circuit adiabatic cooler The cooling circuit type determines the exact heat exchange process.

Additionally, when water flow is low, it disrupts the spray from the nozzles, causing uneven distribution and channeling in the fill material—thus increasing the risk of ice build-up in cold weather or scaling from high mineral concentrations. They also produce more noise as the water sprays from the tower ceiling and tends to have farther to fall. With induced draft, air enters the cooling tower slowly and exits quickly. This reduces the risk that air will recirculate, which makes the cooling process less effective because the air exiting the tower is warmer.

This air enters quickly and exits slowly, which increases the risk of recirculation. However, forced draft generates more static pressure, which makes it more suitable for confined and sometimes indoor spaces. Natural draft uses the architecture of the cooling tower and the principles of air density to create a natural air flow.

Natural draft cooling towers are tall, hyperboloid structures, often used in power plants. As air enters the cooling tower, it gets hotter and more humid, and naturally rises up through the tower like smoke through a chimney.

The fans help circulate air into the tower, but the system primarily uses architecture and the changes in air density to create the draft. Each offers advantages for particular situations. These preassembled units are convenient, but have less capacity—they have to fit on trucks, after all.

Since packaged cooling towers are often used in residential areas, they tend to place greater emphasis on noise-reduction features such as a gravity-fed water distribution system or induced draft, but they can be configured to meet the needs of your facility. Facilities that produce more heat often need towers with greater capacity than what manufacturers can preassemble and ship.

So power plants, refineries, steel processing plants, and other large industrial facilities use field-erected towers, which can be as large as they need to be. The manufacturer typically provides labor and expertise to assemble cooling towers on-site. Depending on the cooling needs of the building or process, the size of the cooling tower dictates how much water is used and heat rejection can be provided. Cooling towers use tonnage as a rating.

Typically, the larger the tonnage, the more water the cooling tower will use. A fluid cooler constantly sprays water on the tubing that contains your hot water, so the heat transfers from the hot water inside the tubing to the cool water outside the tubing. The sprayed water never enters your water supply which is why these are also called closed-circuit cooling towers , and it continually needs to be replenished.

Wet cooling towers use evaporative cooling and expose your hot water to the open air, so your system is constantly losing water through evaporation and drift as vapor and droplets escape through the top of the tower.

Additionally, as the water evaporates, it leaves behind minerals and increases their concentration in your water supply, which—if left alone—could be harmful to your cooling tower and other equipment.

To address this issue, wet cooling towers also remove some of the water from your system. As mentioned previously, this water is called blow-down or draw-off.

To compensate for these three ways in which your wet cooling tower loses water, it uses more. Wet cooling towers constantly add fresh water—called make-up water—to ensure that the same amount of water always returns to your water supply. Cooling towers are a vital part of your water management system. If a single component stops working, it can drastically reduce your ability to efficiently reject heat and keep your equipment or facility cool.

When your cooling tower works less efficiently, it uses more power and costs more money. These problems can also quickly snowball into disasters, interfering with your industrial processes and damaging or destroying your machinery.

Scaling must be removed regularly, or your system has to work harder to transfer heat.