How to Select an EC Axial Fan for a Cooling Tower: A Guide for OEMs

Cooling tower performance depends on more than the tower structure, fill, and water distribution system. The fan also plays an important role in moving air through the cooling tower and supporting the required heat rejection performance.

For cooling tower manufacturers, HVAC equipment builders, and industrial cooling system integrators, selecting the right fan involves balancing airflow, pressure, energy consumption, noise, environmental durability, and control requirements.

An EC axial fan for a cooling tower can be a suitable option when a project requires variable-speed operation, flexible control integration, and an appropriate combination of aerodynamic and electrical performance.

However, choosing a fan based only on its diameter or maximum airflow can lead to an unsuitable selection.

The correct fan must meet the cooling tower's actual operating requirements and fit the intended installation.

In this guide, we explain how to evaluate EC axial fans for cooling towers, what technical specifications matter most, and what information to provide when requesting a quotation from a fan manufacturer.

1. What Does a Fan Do in a Cooling Tower?

A cooling tower rejects heat by bringing water into contact with an airflow or using an air stream to facilitate heat transfer through the designed heat exchange arrangement.

The fan helps move air through the tower. Depending on the cooling tower design, the fan may be configured in an induced-draft or forced-draft arrangement.

The required airflow depends on several factors, including:

• Cooling capacity and thermal duty.

• Entering water temperature and required leaving water temperature.

• Ambient air conditions.

• Cooling tower configuration.

• Fill or heat exchanger characteristics.

• Airflow resistance within the tower.

• Operating conditions and control strategy.

The fan must provide sufficient airflow against the resistance of the complete air path.

An oversized fan is not automatically a better solution, and a high maximum airflow rating does not guarantee that the required airflow will be delivered once the fan is installed.

For cooling tower OEMs, fan selection should therefore begin with the actual system duty point rather than a nominal fan diameter.

2. Why Consider an EC Axial Fan for a Cooling Tower?

Electronically commutated (EC) axial fans combine an axial airflow design with electronically controlled motor technology.

Depending on the selected model and control configuration, EC fans can offer several benefits for cooling tower applications.

Variable-speed operation

Compatible EC fans can adjust their operating speed according to a control signal or supported digital command.

This can help cooling tower systems respond to changing thermal loads instead of operating continuously at one fixed speed.

Actual performance depends on the fan, controller, system design, and required cooling duty.

Potential energy savings

Cooling demand can change throughout the day and across different seasons.

When the cooling tower can meet its thermal requirements at a reduced fan speed, demand-based operation may reduce electrical power consumption.

However, energy savings depend on the actual operating profile, fan characteristics, control strategy, and system resistance.

A meaningful comparison should use relevant performance and power data rather than assume that every EC fan will achieve the same percentage of savings.

Flexible control integration

Depending on the fan model, control options may include:

• 0–10V analog speed control.

• PWM control.

• Modbus-RTU communication.

These interfaces may support integration with compatible cooling tower controllers, PLCs, or building management systems.

The available interfaces and supported functions must be confirmed in the selected model's technical documentation.

Opportunities for OEM integration

For cooling tower manufacturers, an EC axial fan may offer flexibility in electrical connections, control integration, mounting configuration, and selected customization options.

These details are particularly important when the fan is part of a complete cooling tower assembly rather than a standalone replacement.

The key is to evaluate the complete fan configuration against the equipment manufacturer's requirements.

3. Start With the Required Airflow and Pressure

Airflow and pressure are the foundation of fan selection.

Before comparing fan models, the cooling tower designer or system integrator should establish the required airflow and the pressure associated with that duty.

Understand the airflow requirement

Airflow measures the volume of air moved over a specified period.

Common units include:

• m³/h: cubic meters per hour.

• CFM: cubic feet per minute.

• m³/s: cubic meters per second.

US projects often specify airflow in CFM, while international engineering documentation commonly uses m³/h.

Make sure the units are consistent when comparing fan performance data from different manufacturers.

Evaluate system resistance

The pressure requirement reflects the resistance the fan must overcome as air moves through the tower.

Depending on the system design, this can involve resistance from fill, heat exchange elements, protective grilles, airflow transitions, and other components.

The exact pressure requirement should be determined from the cooling tower design or appropriate engineering calculations.

Also confirm whether the requirement is expressed as static pressure or total pressure. These are different quantities and should not be used interchangeably.

Check the fan performance curve

A manufacturer's fan performance curve shows how airflow and pressure relate under specified operating conditions.

To evaluate a candidate fan:

1. Identify the required airflow.

2. Determine the corresponding pressure requirement.

3. Locate the required duty point on the performance chart.

4. Check whether the fan can meet the duty point at the intended operating setting.

5. Review the associated power consumption and available operating range.

Do not assume that a fan's listed maximum airflow is available at every pressure condition.

For additional background, read our guide to How to Read an EC Axial Fan Performance Curve.

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4. Choose the Appropriate Fan Diameter and Installation Configuration

Fan diameter affects the airflow characteristics, available installation space, and overall cooling tower design.

However, the largest available fan is not necessarily the best choice for a particular application.

The correct configuration depends on the required duty point, available space, fan design, speed, and mounting arrangement.

Check the available installation space

Confirm the available fan opening, overall dimensions, mounting points, and required inlet and outlet clearances.

For a cooling tower project, also check compatibility with the fan deck, protective grille, diffuser, supporting structure, and existing airflow path.

Review the fan assembly

The fan assembly may include several components beyond the impeller and motor.

Depending on the design, these may include:

• Protective grille.

• Mounting plate or square flange.

• Diffuser or guide vane.

• Integrated motor and control components.

• Electrical connections and cable arrangements.

These details can influence installation, airflow conditions, maintenance access, and compatibility with the complete tower.

Confirm the airflow direction

Verify whether the fan is intended for the required airflow direction and installation orientation.

Do not assume that all axial fans with similar dimensions are interchangeable.

For OEM projects, reviewing the dimensional drawing and installation instructions before ordering can help prevent avoidable design changes during assembly.

5. Evaluate Corrosion Protection and Outdoor Durability

Cooling towers commonly operate in environments where moisture, water droplets, temperature changes, and outdoor exposure can affect equipment durability.

The suitability of an EC axial fan therefore depends on its environmental specifications as well as its aerodynamic performance.

Check the protection rating

Ingress protection ratings indicate the degree of protection provided by an enclosure against specified ingress conditions.

Select a fan with a protection rating suitable for the intended installation and electrical configuration.

For example, Belmont Fan's cooling tower product range identifies IP54/IP55 protection options for relevant configurations.

The appropriate rating should be confirmed for the exact model rather than assumed across the entire product range.

Consider corrosion exposure

Corrosion resistance depends on the materials, coatings, fasteners, connectors, and environmental conditions involved.

Before selecting a fan, evaluate:

• Ambient humidity and exposure to water droplets.

• Contact with cleaning agents or treatment chemicals.

• Salt or other corrosive contaminants where applicable.

• UV exposure for outdoor components.

• The corrosion resistance of the impeller and mounting structure.

• The durability of electrical connectors and cable entries.

A protection rating alone does not establish that every component is suitable for a corrosive environment.

If the cooling tower operates under demanding environmental conditions, specify those conditions clearly and ask the manufacturer to confirm the suitability of the proposed materials and protection options.

Check the permissible ambient temperature

Different EC fan models have different operating temperature limits.

Verify the permitted ambient temperature range for the selected fan and consider the actual installation environment.

The fan must remain within the manufacturer's specified limits under the intended operating conditions.

6. Consider Noise Performance

Noise can be an important consideration for commercial cooling towers installed near offices, hotels, residential buildings, or other noise-sensitive locations.

When comparing EC axial fans, avoid relying solely on a product description that uses terms such as “low noise.”

Instead, request relevant acoustic data and confirm the measurement conditions.

Important factors include:

• Sound power or sound pressure level.

• Measurement method and test environment.

• Operating speed and airflow conditions.

• Fan mounting and installation configuration.

• Potential structural vibration.

• Nearby objects that may affect the airflow or acoustic environment.

Sound power and sound pressure are different measurements and should not be compared directly without understanding the measurement basis.

The fan's performance curve should also be checked against the required airflow and pressure. A fan selected only for low noise may still be unsuitable if it cannot meet the cooling tower's required duty.

For the complete installation, the tower structure, surrounding barriers, discharge arrangement, and vibration transmission can also affect the final acoustic result.

7. Choose the Right Control Method

EC axial fans may support different control methods, depending on the model and configuration.

The control interface should match the cooling tower's control system and operating requirements.

0–10V analog control

A compatible controller sends a variable analog signal to adjust fan operation.

This can be suitable when the cooling tower controller already provides an appropriate analog output and the application mainly requires variable-speed control.

PWM control

Pulse-width modulation can be used on compatible fan and controller combinations.

Check the required signal characteristics and electrical interface before specifying this option.

Modbus-RTU communication

Compatible Modbus-RTU fans can communicate with a controller through a supported digital interface.

Depending on the model, the interface may provide speed commands, status information, or other functions exposed through the manufacturer's register map.

Do not assume that all fan parameters are available through Modbus. Confirm the supported commands and monitoring data for the exact model.

Which control method should you choose?

The decision depends on the existing control architecture and the level of monitoring required.

For straightforward variable-speed control, 0–10V may be sufficient.

For an application that requires supported digital commands or fan-level status information, Modbus-RTU may be more appropriate.

For OEM projects, decide the control method during the design stage. This allows the fan interface, wiring, controller, and commissioning procedure to be evaluated together.

Read more in our upcoming technical guide on 0–10V vs. Modbus-RTU Control for EC Axial Fans.

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8. Evaluate Power Consumption at the Required Operating Point

Rated power is useful for understanding a fan's electrical characteristics, but it does not by itself establish whether one fan is more energy-efficient than another.

To compare two EC axial fan options fairly, evaluate their performance under comparable operating conditions.

Review:

• Required airflow.

• Corresponding pressure.

• Electrical input power at the operating point.

• Permitted operating range.

• Expected load profile.

• Control strategy and minimum operating speed.

For a cooling tower that operates at variable loads, it may also be useful to assess energy consumption across representative operating conditions rather than looking only at maximum-speed operation.

The overall cooling tower must still meet the required thermal performance. Fan speed should not be reduced below what the system needs to maintain its design or operating requirements.

Where energy savings are a project priority, request relevant performance data and evaluate it against the application's actual duty cycle.

9. Belmont EC Axial Fan Options for Cooling Towers

Belmont Fan has a dedicated cooling tower application page featuring EC axial fan solutions for industrial and commercial cooling tower applications.

The page identifies several product characteristics relevant to cooling tower manufacturers, including:

• EC motor technology with supported speed-control options.

• IP54/IP55 protection options for relevant configurations.

• Corrosion-related design considerations.

• Low-noise aerodynamic designs.

• Integrated mounting structures and selected accessory options.

Available specifications and configurations depend on the selected model.

Explore the Belmont EC Axial Fans for Cooling Towers application page.

Example: 710mm EC Axial Fan for Cooling Tower Applications

Belmont Fan lists the following product for cooling tower applications:

Product: 710mm Low Maintenance EC Axial Fan for Cooling Tower

Model: BEFEC137-A710-C01

View the 710mm EC Axial Fan for Cooling Tower

This product page provides the model's available technical specifications, including its electrical configuration, speed, power, protection rating, and performance information.

For your application, review the full performance curve and dimensional drawings before determining whether the model meets the required airflow and pressure.

Do not select a fan based only on its nominal diameter or maximum airflow rating.

Example: 910mm EC Axial Fan for Cooling Tower Applications

Belmont Fan also lists a larger EC axial fan for cooling tower applications.

Product: BEF(K)8D910-PFE5SL1-RF EC Axial Fan for Cooling Tower

View the 910mm EC Axial Fan for Cooling Tower

The product page includes performance information, installation dimensions, electrical specifications, and available control information.

For larger cooling tower assemblies, confirm that the selected fan's operating point, mounting configuration, environmental suitability, and control interfaces match the project requirements.

These product examples are starting points for technical evaluation, not a substitute for application-specific fan selection.

10. What Should Cooling Tower OEMs Provide When Requesting a Quotation?

A well-prepared inquiry helps the fan manufacturer understand the project and assess suitable configurations.

Before requesting a quotation, prepare the information below wherever available.

If the project is a replacement application, also provide the existing fan's model number, nameplate photograph, dimensional drawing, and available performance curve.

If airflow or pressure requirements are not yet known, share the cooling tower design information and the specifications currently available rather than estimating these values without supporting data.

The manufacturer can then identify which additional information is needed to review the selection.

11. Common Mistakes When Selecting a Cooling Tower Fan

Avoid these common mistakes when choosing an EC axial fan for a cooling tower.

Selecting by diameter alone

Two fans with the same nominal diameter can have different performance characteristics, dimensions, and control capabilities.

Comparing only maximum airflow

Maximum airflow does not establish whether a fan can meet the required airflow at the tower's operating pressure.

Ignoring outdoor conditions

A fan that meets the duty point may still be unsuitable if its protection, materials, connectors, or temperature rating do not match the installation environment.

Assuming every EC fan supports the same control methods

Available interfaces and monitoring functions vary by model. Confirm compatibility before specifying the fan.

Treating a protection rating as a corrosion-resistance guarantee

Ingress protection and corrosion resistance address different aspects of suitability. Review the complete material and environmental specifications.

Ignoring the full cooling tower design

The fan must operate within the requirements of the complete air-moving and heat-rejection system.

A structured selection process reduces the risk of an unsuitable fan specification and helps OEMs integrate the fan more efficiently into the finished equipment.

12. Request an EC Axial Fan for Your Cooling Tower Project

Selecting an EC axial fan for a cooling tower involves matching airflow and pressure requirements with the required mechanical design, environmental protection, noise performance, electrical supply, and control system.

For cooling tower manufacturers and equipment OEMs, these factors should be reviewed together before finalizing the fan configuration.

Belmont Fan provides EC axial fan solutions for cooling tower and other HVAC applications, with specifications and available configurations depending on the selected model.

Looking for an EC axial fan for your cooling tower project?

Contact Belmont Fan with your application details, required airflow and pressure, fan dimensions, electrical supply, control requirements, and expected quantity.

Our team can review the available information and help assess a suitable fan configuration.

Explore the product range: Belmont EC Axial Fans for Cooling Towers

Email: sales@belmont-tech.com

Website: https://www.belmont-tech.com/

Frequently Asked Questions

How do I choose an EC axial fan for a cooling tower?

Start with the required airflow and system pressure. Then evaluate the fan's performance curve, dimensions, electrical supply, control interface, noise requirements, and environmental suitability.

Are EC axial fans suitable for industrial cooling towers?

They can be suitable for cooling tower applications when the selected model meets the required airflow, pressure, installation, electrical, and environmental requirements. Final selection should be based on the complete duty point and product documentation.

What is the most important specification when selecting a cooling tower fan?

Airflow and pressure must be evaluated together. Fan diameter, speed, power, control options, and environmental requirements are also important, but they do not replace duty-point verification.

Can an EC axial fan adjust its speed according to cooling demand?

Many EC axial fans support variable-speed operation through compatible control interfaces. The available control methods and operating ranges depend on the specific model and controller.

What protection rating should a cooling tower EC fan have?

The appropriate rating depends on the installation's moisture exposure, environmental conditions, and electrical design. An IP rating should be checked alongside the fan's material specifications and corrosion-related requirements.

Can a cooling tower fan be selected using maximum airflow alone?

No. Maximum airflow is useful for an initial comparison, but the final selection must establish whether the fan can deliver the required airflow at the actual system pressure.

What information should I provide for an EC cooling tower fan quotation?

Provide the application, required airflow and pressure, fan dimensions, voltage, phase, frequency, control interface, environmental conditions, acoustic requirements, and quantity. Existing fan drawings or performance data can also help.

Choosing the right EC axial fan for a cooling tower starts with understanding the complete system requirements. By evaluating the duty point, environmental conditions, control integration, noise, and installation configuration together, cooling tower manufacturers and OEM buyers can make a more informed fan selection.