Forward Curved Vs Backward Curved Centrifugal Fan Efficiency

Motor selection must take this into account.

Forward curved vs backward curved centrifugal fan efficiency.

The optimum operating area for a forward curved centrifugal fan is when it is operating at higher pressure. On the other hand those with backward curved blades are basically free wheeling fans. Another important design feature is the position of the motor. The most common hvac fans are axial forward curved centrifugal and backward inclined and each is uniquely suited to certain purposes.

Do not rate fan in the pressure curve dip to the left of peak pressure. Forward curved fan. Pressure curve less steep than that of backward curved. 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.

Motor selection must take this into account. As with the backward curved centrifugal fan the suction side of the impeller blade draws air from the centre of the fan which results in a directional change of the airflow between the inlet and the exhaust of 90 o. 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.

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. Backward curved these wheels are extremely efficient more robustly built and very quiet. Power rises continually toward free delivery. Power rises continually toward free delivery.

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. The modern forward curved blades are designed with a scroll housing. This reduces the level of noise. In most cases these fans are designed with external motors.