When it comes to forced air cooling, fans are an essential component. Depending on the required airflow, speed and noise level, available supply voltage or dimensions of the object to be supplied (e.g. heat sinks), users can choose from our wide range of axial fans, blowers and impellers both for AC and DC operation. All our fans are designed to achieve high air flow performance, low-noise operation and low power consumption.
Of the many possibilities to dissipate heat from devices, systems or components without using liquids, forced convection cooling by means of fans is the most effective. Several factors are important in determining the right fan or blower for a particular application.
Fan Type, Shape and Dimensions
Axial or tubaxial fans are preferred for applications where high air flow is requested at moderate pressure. Operated at nominal conditions, axial fans feature low noise operation. Blowers or radial fans, on the other hand, are particularly suitable when high pressure with moderate air flow is required and moderate noise is acceptable. Impellers also generate radial air flow but provide both high pressure and high air flow - at moderate operating noise. Depending on the mechanical constraints in the system, users can choose between square, rectangular or round designs that optimally match the conditions.
If you do not need the possibility to control the speed of the fan and only want a constant air flow, AC fans (Alternating Current) are the right choice: they can be connected directly to mains and can reduce the load on your system power supply. On the other hand, you can control a DC (Direct Current) fan’s speed and airflow, regardless of voltage and frequency fluctuations in the mains. A single DC fan can also - operated with different voltages - meet the requirements of several applications. Our choice of voltages provides a good match with the DC voltages available in your system.
EC fans (Electronically Commutated) are also powered directly from mains, but convert the AC voltage internally into a regulated DC voltage that drives a brushless DC (BLDC) motor. This makes it possible to operate these fans with a wide input voltage range while maintaining constantly low current consumption and a long lifetime.
Evacuation vs. Pressurization
Forced convection heat transfer can be achieved in two ways: evacuation or pressurization of the cabinet. When evacuating a cabinet (fan on the outlet side), the air distribution in the cabinet is flexible. Air inlets can be placed anywhere in the enclosure to ensure adequate cooling in the desired locations. In addition, the heat from the fan itself is not dissipated to the cabinet. However, because this configuration makes it extremely difficult to filter the fan on the exhaust side, pressurizing the cabinet is considered the preferred method, as the incoming air can be easily filtered here.
Air Flow and Static Pressure
Before you can specify the right fan for your application, the air flow required to dissipate the generated heat must be known approximately. The density of the air and the quantity of heat to be dissipated must also be available as values. Once the air flow (with the unit m3/hr) is known, we need to determine the flow resistance in the system. This flow resistance is expressed in static pressure as a function of the flow and cannot easily be calculated for complex systems – in this case only static pressure measurements yield accurate results.
With air volume and static pressure of the system known, it is now possible to specify a fan. But keep in mind that any fan can only provide one volume flow at one pressure in a given system - as much air as the system will let through for that pressure. Tight dimensioning of a fan’s air flow can lead to the choice of a high performance, rather noisy model that consumes a lot of power and can even be more expensive than a larger model with more “headroom” for the application (if dimensions and space are not critical). If, on the other hand, the required air volume and static pressure in the system are optimized, significantly lower performance, noise and cost levels are usually possible. It might also help to change the shape (square, rectangular, round) of the fan to reach the desired performance.