Fan Law Calculator
The Fan Law Calculator (also known as Affinity Laws calculator) is used to predict the performance changes of a centrifugal fan or pump when its speed (RPM) or other parameters change. These laws describe the relationships between flow rate (CFM), static pressure (SP), and brake horsepower (BHP) with respect to changes in fan speed or impeller diameter. This calculator typically requires initial operating conditions (CFM, SP, BHP, RPM) and a desired new RPM or new target CFM. It's a fundamental tool for system balancing, energy optimization, and troubleshooting fan performance.
Practical Applications of Fan Laws: Fan affinity laws are useful for system balancing (estimating how a change in fan speed will affect airflow), understanding energy savings (BHP varies with RPM cubed, so reducing speed significantly cuts power), troubleshooting fan performance, and making design adjustments if a slightly different operating point is needed after initial design. These laws are most accurate when the fan remains on the same system curve and air density is constant.
Fan laws assume the fan is operating on the same system curve and that air density remains constant. These calculations are theoretical predictions. Actual performance may vary due to motor efficiency, belt losses (if applicable), and changes in system resistance. Not applicable if fan size or type changes.