Classification by Physical Design and Orientation
A. Cylindrical / Round (Most Common Induced Draft Type)
- This is the iconic, hyperboloid-shaped tower (though modern ones are often cylindrical).
- Design: The induced draft fan is mounted vertically on top. Water is sprayed over the coil bundle, and air is drawn in through the louvers around the entire circumference, flowing cross-current to the water.
- Advantages:
- Compact footprint.
- Even air distribution.
- Modular and easily shipped.
- Image: This is what most people picture as a “cooling tower.”
B. Flat Top / V-Flow (Induced Draft)
- Design: A box-shaped, induced draft tower. Air is drawn in from the sides and makes a V-shaped path through the coil bundles before exiting the top fan. This design often uses a “counter-flow” principle where air flows vertically up while spray water flows vertically down.
- Advantages:
- Often more efficient heat transfers due to counter-flow design.
- Lower height profile than cylindrical towers.
- Coils can be easier to access and service.
- Best for: Applications where efficiency is paramount or height restrictions exist.
C. Horizontal (Forced Draft)
- Design: Features a box-like design with forced draft fans mounted on the side, blowing air horizontally through the coil and wet deck media. The air is discharged horizontally out the opposite side.
- Characteristics:
- Very low profile, often called “low-profile” or “penthouse” towers.
- Can be equipped with multiple fans for redundancy.
- Best for: Rooftop installations, areas with strict height limitations, and noise-sensitive environments (the fan can be fitted with sound attenuators).
Summary Table: Key Types of Closed Circuit Cooling Towers
| Type | Airflow Method | Fan Location | Key Characteristics | Best For |
| Cylindrical Induced Draft | Induced Draft | Top | Compact footprint, even air distribution, most common | Standard outdoor industrial & HVAC applications |
| Flat Top / V-Flow | Induced Draft | Top | Counter-flow efficiency, lower height, serviceable | High-efficiency needs, height restrictions |
| Horizontal Forced Draft | Forced Draft | Side | Very low profile, redundant fan options, quieter | Rooftops, architectural restrictions, noise zones |
| Natural Draft | Natural Buoyancy | None | Massive scale, very high capital cost, zero opera |