Key Points in The Design of Cooling Tower Fan Stack

Key Points in The Design of Cooling Tower Fan Stack

In the cooling tower system, the cooling tower fan stack is a key component that affects airflow organization, fan efficiency, and overall tower performance. Reasonable wind duct design can not only reduce energy consumption, but also improve cooling efficiency and extend equipment service life. This article will focus on the design points of the cooling tower fan stack, and provide a systematic analysis from the aspects of structure, materials, aerodynamic performance, and installation and maintenance.

The role of cooling tower fan stack

1）Improve airflow stability

The core function of the cooling tower fan stack is to guide air smoothly out of the cooling tower, reduce backflow and turbulence, and thus form a stable vertical airflow channel.

2）Reduce energy consumption of fans

By designing a reasonable height and curve of the air duct, the outlet resistance can be reduced, allowing the fan to operate at a higher efficiency point and reducing overall energy consumption.

3）Protect the fan system

A well-designed cooling tower fan stack can also reduce the interference of external crosswinds on fan blades, improving operational safety and reliability.

Key points of structural design for cooling tower fan stack

1）Fan duct height design

The height of the air duct directly affects the ventilation effect. Generally speaking, the higher the height, the more conducive it is to forming a stable negative pressure zone, but it is necessary to comprehensively consider the structural strength and cost control.

2）Export diameter and diffusion angle

A reasonable diffusion angle (usually 7 ° -12 °) can help reduce airflow separation and improve aerodynamic efficiency. The outlet diameter should be matched with the fan to avoid the formation of secondary resistance.

3）Inner wall smoothness

The inner wall of the cooling tower fan stack should be as smooth as possible to reduce frictional resistance. The common practice is to use fiberglass or anti-corrosion coated steel plate as the lining material.

Material selection and durability

Common material types

Fiberglass reinforced plastic (FRP): 

lightweight and corrosion-resistant

Galvanized steel plate: 

low cost, high strength

Stainless steel: 

suitable for highly corrosive environments

Anti corrosion and anti-aging design

The cooling tower fan stack must have good anti-corrosion and UV resistance properties to extend its service life when exposed to humid, hot, and chemical environments for a long time.

Aerodynamic Performance Optimization Design

Reduce eddy currents and backflow

Adding a guide curve design at the outlet of the air duct can significantly reduce vortex intensity and improve air discharge efficiency.

Matching design with fan

The size parameters of the cooling tower fan stack must match the fan air volume and speed to avoid fan surge or efficiency reduction caused by improper design.

Wind noise control

By optimizing the structural shape and lining sound-absorbing materials, it is possible to effectively reduce operating noise and meet environmental requirements.

Key points of installation and maintenance

Installation accuracy requirements

The cooling tower fan stack must be kept concentric with the fan axis to avoid eccentricity causing vibration and structural fatigue.

Regular inspection content

1）Check if the connecting bolts are loose

2）Check for scaling or corrosion on the inner wall

3）Check for cracks in the structure

Cleaning and Repair

Regularly cleaning the dirt inside the air duct helps maintain smooth airflow and ensure the long-term efficient operation of the cooling tower.

The Development Trend of Cooling Tower Fan Stack Design

Lightweight design

By applying new composite materials, lighter structural weight can be achieved while ensuring strength and stability.

Modular structure

The modular cooling tower fan stack is convenient for transportation and on-site installation, and also facilitates later maintenance and replacement.

Digital simulation design

Using CFD simulation technology to optimize and analyze airflow distribution, making the design more scientific and accurate