Cooling towers are the best heating, ventilation and air conditioning equipment for commercial and industrial spaces. They are scalable and highly practical for buildings and facilities that measure thousands of square feet. Fundamentally, cooling towers reject unwanted heat from a building and send it back to the atmosphere. They do this by manipulating the flow of two of their primary ingredients: water and air.
Cooling towers rely on the evaporation of the water in the system to transfer excess heat out of the building. However, some types of cooling towers depend solely on the flow of air. The following information will help you understand the counterflow and crossflow mechanisms of cooling towers:
- Counterflow in Cooling Towers
Cooling towers that rely on the counterflow working mechanism have a characteristic tall and compact structure. The air moves through the cooling tower in the opposite direction to the flow of the water. The air enters the chamber through an open section just below the fill media of the cooling tower. It moves up vertically against hot water flowing downwards from high-pressure nozzles. The nozzles sit strategically to ensure that water and air always move in opposite directions. This allows maximum contact between the two parameters and facilitates heat transfer.
Counterflow cooling towers have more pump head requirements because the water has to flow under pressure. This increases the overall running costs. However, there is an excellent distribution of water, which makes the cooling tower more resistant to freezing.
- Crossflow in Cooling Towers
Cooling towers with a crossflow working mechanism rely on gravity to move the water through the cooling tower system. There is no need for pressurised nozzles at the water outlet points. In this design, hot water flows in the same direction as the flow of the air. The movement happens in two parallel chambers next to one another. Air passes through an open space into one of the vertical columns where it encounters the fill material. At the same time, water flows parallel to the air under the natural push of gravity into the fill. The interaction at this point allows heat transfer to happen with air leaving the fill at the desired temperature. It is ready for circulation to the rest of the building.
Crossflow cooling towers are popular because of low running costs. Relying on gravity to distribute the water in the system relieves you of pump demands. To add on that, non-pressurised water sprays make it easy to vary the flow of water through the fill media.