When selecting a fan system for a unique application, there are specific sets of criteria to consider. Because of the wide variety of fan and motor types, product designers and engineers may find it challenging to select the right fan/motor configuration for their specific applications. Consulting with experts can lead to quicker and more exact system success.

Cooling requirement

Assuming that these designers and engineers are cooling components within an electronic enclosure, the first step of this process is to determine how much heat the fan needs to dissipate. A first-order estimate might simply involve measurement of the uncooled component temperature and knowing the size of the component’s power supply (in Watts). Systems that are subjected to additional heating sources through radiation, conduction or convection may require more detailed thermal analysis, which may employ more sophisticated tools, such as computational fluid dynamics (CFD) analysis.

Fan CFM requirement

By knowing the amount of heat that needs to be dissipated, it is possible to determine the air volumetric flow rate in cubic feet per minute (CFM) required for cooling. This can be done using sophisticated analyses, such as CFD, or by use of numerous online tables and software that can provide a first-order estimate.

When a fan is used to cool components within an electronic enclosure, there will be an increase in the static pressure within the enclosure due to resistance, or impedance, of the air flow from the fan inlet to the outlet vents. This can reduce the amount of heat a fan can remove from an enclosure, requiring the selection of a fan with a higher CFM rating.

Manufacturers will typically plot the performance characteristics of their fans in graphical form based on their diameter, speed and blade pitch angle. An example of one of these plots, known as the fan performance characteristic curve, can be seen in Figure 1. Most fan characteristic curve plots will show the fan air volume (in CFM) versus the static pressure and brake horsepower. The static pressure is the pressure within the enclosure and the brake horsepower is the power needed to operate the fan at the given pressure and air volume.

Figure 1. Fan performance curves. Source: Pelonis Technologies, Inc.

Electronic system designers and heat transfer engineers can evaluate several different fan performance curves to determine the fan types and motors needed to cool their specific application. Other factors that may affect the selection of an appropriate fan might include space constraints, the motor drive configuration, efficiency, noise, cost, delivery time and availability.

Pelonis Technologies

Pelonis Technologies is ready to assist in selecting the right fan system for specific applications. With over 25 years of product development and manufacturing experience, Pelonis Technologies is committed to providing exceptional quality, product innovation and service at competitive pricing. More information about Pelonis and their fan technology can be found at the Pelonis Technologies website.