What are the key factors in fan selection?

Fan selection is a complex process that starts with a basic knowledge of system operating conditions. The key factors in fan selection are: air properties (moisture content, temperature, density, contaminant level, etc.), airflow rate, pressure, and system layout.

What happens if you change the fan performance capability?

When you change the fan performance capability, the operating point moves along the established system resistance curve. By adjusting both the system and the fan performance, the operating point can be moved to almost any desired position under the fan curve.

What makes a good fan system?

A key fact is that the right decisions should be taken early - earlier than usual in practices. ◼ Good system assessment goal and methods: A good system can be assessed by the specific fan power combined with the need to optimize demand, control and operation. Electricity consumption can serve as a control for compliance with these requirements.

How are CFM and RPM related in a fan system?

In a fan system, CFM and RPM are related in a known manner. When one changes, the other changes as well. CFM is the most commonly changed measurement in an air moving system. Therefore, Fan Law applications are often based on a change from an existing CFM to a new CFM.

How can fan speed be controlled?

Fan speed can be controlled through drive changes or a variable speed motor. The speed changes represent an example of fan control. It is extremely important to know the individual performance characteristics for each type of fan when working on efficient control strategies and/or energy conservation.

What is the basis for selecting a fan size?

After deciding which fan type is appropriate, the right size must be determined. Fans are usually selected on a “best-fit” basis rather than designed specifically for a particular application. A fan is chosen from a wide range of models based on its ability to meet the anticipated demands of a system.