Power rises continually toward free delivery.
Forward curved vs backward curved centrifugal fan efficiency.
Do not rate fan in the pressure curve dip to the left of peak pressure.
The most common hvac fans are axial forward curved centrifugal and backward inclined and each is uniquely suited to certain purposes.
In most cases these fans are designed with external motors.
Pressure curve less steep than that of backward curved.
Power rises continually toward free delivery.
Flatter pressure curve and lower efficiency than the airfoil backward curved and backward inclined.
It s important to understand each fan s differences in energy efficiency cost effectiveness and noise considerations.
The non overloading characteristic the ability to install the fan with or without a scroll and an impeller design that offers the highest static efficiency of all types of fans means that the backward curved fan is a flexible adaptable fan design can be used across a wide range of installations.
Backward curved centrifugal fans.
Do not rate fan in the pressure curve dip to the left of peak pressure.
Flatter pressure curve and lower efficiency than the airfoil fan backward curved fan and backward inclined fan.
Forward curved fan.
Another important design feature is the position of the motor.
Motor selection must take this into account.
Backward inclined the performance of the backward inclined wheel is similar to the forward curve however bi fans tend to be non overloading meaning their fan curves do not tend to increase hp as static pressure changes but cfm falls off.
Motor selection must take this into account.
Forward curved centrifugal fans are more cost effective than backward curved centrifugal fans though and have become popular in industries like the medicinal industries since they don t accumulate chemicals and other debris on their blades.
This reduces the level of noise.
The modern forward curved blades are designed with a scroll housing.
The optimum operating area for a forward curved centrifugal fan is when it is operating at higher pressure.