Applications of axial fans
Various types of ventilation systems are available on the market depending on their field of use and technical requirements. Fans are devices that optimize heating, ventilation, and refrigeration processes both in industrial settings and in everyday applications.
Centrifugal fans: what they are and types
Let’s start with definitions. A fan is a device that allows fluid movement. In industrial settings, for example, it is used for managing fluids within plants, machinery, and production lines. Therefore, it is an essential and indispensable tool for efficiency and safety.
The two main parameters that define industrial fans are:
- The fluid flow rate, expressed in cubic meters per hour (m³/h)
- The total pressure of the fan on the fluid, expressed in Pascals (Pa)
From a macro perspective, there are two main categories of fans: centrifugal fans and axial fans. Both – with their respective differences – are used in blowers, exhausters, HVAC (Heating, Ventilation, and Air Conditioning) systems, and compressors.
Centrifugal fans vs axial fans: substantial differences
From a technical and application perspective, there are various differences between centrifugal and axial fans.
Centrifugal fans release air at a right angle to the fan intake. The air is rotated towards the outlet by centrifugal force and the curvature of the blades. Through rotation, the air enters the fan near the shaft and is directed perpendicularly to the fan’s axis towards the outside. The air is thus centrifuged outward, undergoing a 90-degree direction change between the intake and the outlet. In contrast, in axial fans, the drawn air moves parallel to the shaft around which the blades rotate.
Centrifugal fans have a medium-large fan diameter, medium to high flow rate, characterized by high pressure and low noise emissions. In industrial settings, they must operate continuously without interruptions and withstand various temperatures and flow rates.
Centrifugal fans have a flat spiral-shaped outer casing and a centrifugal fan inside. The blades are arranged circularly along the rotation axis.
From a technical standpoint, there are two types of centrifugal fans:
- Forward-curved blades: This type has more blades. Although efficiency and flow rate are generally lower than with backward-curved blades, the pressure is higher. Additionally, both single and double inlet fans of this type are available on the market.
- Backward-curved blades: The blades are oriented in the opposite direction and are fewer in number than the forward-curved type. This configuration offers greater efficiency, higher flow rate, and slightly lower pressure.
Compared to centrifugal fans, axial fans can reach much larger fan diameters, have a higher flow rate, and lower pressure. In most applications, they are typically smaller, lighter, and less expensive, except for some industrial applications where very high flow rates are required.
Applications of axial fans
Axial fans are ideally suited for environments where reduced space and high flow rates under complex operating conditions are required.
A primary example is industrial and process refrigeration equipment. These are systems with naturally low temperatures and characterized by large overall dimensions. In this context, axial fans offer the right performance at lower costs compared to centrifugal fans. A similar application is commercial refrigeration, such as refrigerated display cases. Here too, axial fans allow for temperature control with minimal space requirements.
Larger axial fans find applications in heat pumps and condensers, which require high dynamic pressures.
Centrifugal and axial fans: choosing the right product
As we have seen, centrifugal and axial fans meet different needs in terms of performance, structural parameters, and naturally the final output. Choosing the most suitable device requires an analysis of the system and its technical characteristics. This allows for the design of a high-performing system in line with the required objectives.
