A Forced Draft Cooling Tower is a type of mechanical draft cooling tower in which a fan (or multiple fans) is installed at the air inlet to force air into the tower. This design contrasts with an induced draft cooling tower, where the fan is placed at the discharge side to pull air through the tower.
Key Features of Forced Draft Cooling Towers:
- Fan Placement:
- Fans are located at the base (or air inlet) of the tower.
- Air is pushed (forced) into the tower, creating positive pressure inside.
- Airflow Direction:
- Air enters from the sides/bottom and moves upward, counterflow or crossflow to the falling water.
- Advantages:
- Better fan maintenance access (fans are at ground level).
- Reduced recirculation of warm, moist exhaust air.
- More stable performance in windy conditions (compared to induced draft).
- Easier to inspect and repair motors and fans.
- Disadvantages:
- Higher energy consumption (fans work against static pressure).
- Potential for icing in cold climates (since fans are at the inlet).
- Louder operation compared to induced draft towers.
- Applications:
- Industrial cooling systems (power plants, refineries, chemical plants).
- HVAC systems in large buildings.
- Any application requiring precise control of cooling capacity.
Comparison with Induced Draft Cooling Towers:
| Feature | Forced Draft | Induced Draft |
| Fan Position | Air inlet | Air outlet |
| Pressure | Positive inside | Negative inside |
| Energy Use | Higher | Lower |
| Noise | Louder | Quieter |
| Maintenance | Easier | Harder (fans at top) |
Forced draft cooling towers are preferred when maintenance accessibility and stable performance in windy conditions are critical, while induced draft towers are often chosen for energy efficiency and quieter operation. The selection depends on the specific cooling requirements and environmental conditions.