Fan Efficiency

on . Posted in Fluid Dynamics

Fan efficiency, abbreviated as \(\eta_f\) (Greek symbol eta), a dimensionless number, is the effectiveness with which a fan or blower converts the mechanical energy input into useful airflow and pressure.  It's an important parameter in various industries, including HVAC, industrial processes, and ventilation systems, where fans are commonly used to move air and gases. 

  • Higher fan efficiency  -  Indicate that a larger portion of the input energy is being effectively used to move air.
  • Lower fan efficiency  -  Suggest energy losses due to factors like friction, turbulence, and inefficiencies in the fan design.

Factors that influence fan efficiency include the design of the fan blades, the shape of the housing, the type and quality of the motor, and the system in which the fan operates.  Proper fan selection, maintenance, and operation are crucial for achieving and maintaining high fan efficiency.

Improving fan efficiency can lead to energy savings, reduced operational costs, and decreased environmental impact.  Engineers and designers often work to optimize fan systems for specific applications to achieve the desired airflow and pressure requirements while minimizing energy consumption and losses.


Fan Efficiency formula

\( \eta_f \;=\; ( P_{out} \;/\; P_{in} ) \; 100   \)     (Fan Efficiency)

\( P_{out} \;=\; \eta_f \; P_{in} \;/\; 100 \)

\( P_{in} \;=\; P_{out} \; 100 \;/\; \eta_f \) 

Symbol English Metric
\( \eta_f \)  (Greek symbol eta) = fan efficiency   \( dimensionless \)
\( P_{in} \) = input power \( W \) \( W \)
\( P_{out} \) = output power \( W \) \( W \)


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Tags: Efficiency