An open (wet) cooling tower is a heat rejection device that removes waste heat from a water stream by evaporative cooling. It is commonly used in HVAC systems, power plants, and industrial processes to cool water that has absorbed heat from machinery or processes.
How an Open Cooling Tower Works:
- Hot Water Inlet – Warm water from the process is pumped to the top of the tower.
- Distribution System – The water is evenly distributed over the fill media (also called “wetting deck” or “packing”), which increases the surface area for evaporation.
- Airflow – A fan (forced draft or induced draft) draws ambient air through the fill media.
- Evaporative Cooling – As air passes over the water, a small portion evaporates, removing latent heat and cooling the remaining water.
- Cooled Water Collection – The cooled water collects in the basin and is recirculated back to the process.
- Drift Eliminators – Prevent water droplets from escaping with the exhaust air.
Key Components:
- Fill Media – Enhances heat transfer by maximizing water-air contact.
- Fan(s) – Provide airflow (axial or centrifugal).
- Drift Eliminators – Reduce water loss.
- Water Distribution System – Spray nozzles or gravity-fed distribution.
- Basin – Collects cooled water for recirculation.
Advantages:
- High cooling efficiency due to evaporation.
- Lower operational costs compared to dry coolers.
- Effective in high-temperature cooling applications.
Disadvantages:
- Water loss due to evaporation, drift, and blowdown.
- Risk of Legionella growth if not properly maintained.
- Requires water treatment to prevent scaling, corrosion, and biological growth.
Applications:
- Power plants (condenser cooling)
- Refineries & chemical plants
- HVAC systems for large buildings
- Data centre cooling
Maintenance Requirements:
- Regular water treatment (biocides, anti-scaling agents).
- Cleaning of fill media to prevent clogging.
Inspection of fans, motors, and drift eliminators