Cooling fans are used in a wide range of electronic devices, computers and other equipment to dissipate heat buildup. Insufficient heat dissipation can reduce equipment performance, erode components and lubricants prematurely, as well as raise safety considerations for operating personnel and end users. Therefore, a thorough fan selection process is essential to the success of any system.

The first step in this process is a thermal analysis to determine the required air volume and pressure for the cooling system. This data can then be combined with the system impedance to locate the Fan Operating Point where the change slope of the fan characteristic curve is minimized and the overall static efficiency (air flow times static pressure divided by power consumption) is maximized.

After the required air volume is determined, the next step in the fan selection process is to select a suitable fan type. Fans are generally classified as axial, centrifugal or blower fans. Axial fans have the air enter and exit in the same plane and are similar to airplane propellers, generating aerodynamic lift and pressurizing the air streams. These types of fans are ideal for applications requiring high airflow with low static pressure.

Centrifugal fans have the air enter in one plane and the exhaust exit in another. These types of fans have rotating impellers that increase the speed of air streams and convert them to high pressures. These fans are designed for applications requiring relatively high airflow with moderate static pressure. Finally, blower fans have blades that are curved rather than straight to reduce noise levels.Mousepads