Fan Efficiency

Written by Jerry Ratzlaff on . Posted in Fluid Dynamics

Fan efficiency, abbreviated as \(\eta_f\) (Greek symbol eta), a dimensionless number, is the ratio of input and output power.

 

Fan Efficiency formula

\(\large{ \eta_f = \frac{ P_{out} }{ P_{in} } }\)   

Where:

 Units English Metric
\(\large{ \eta_f }\)  (Greek symbol eta) = fan efficiency \(\large{ dimensionless }\)
\(\large{ P_{in} }\) = input power (watt) \(\large{ W }\) \(\large{ W }\)
\(\large{ P_{out} }\) = output power output (watt) \(\large{ W }\) \(\large{ W }\)
\(\large{ I }\) = current \(\large{ I }\) \(\large{ I }\)
\(\large{ V }\) = volt \(\large{ V }\) \(\large{ V }\)
\(\large{ p }\) = air pressure (\(inch\; H_2 O\)) \(\large{ \frac{lbf}{in^2} }\) \(\large{ Pa }\)
\(\large{ Q }\) = air flow (cfm) \(\large{ \frac{ft^3}{min} }\) \(\large{ \frac{m^3}{min} }\)

Solve for:

\(\large{ P_{in} = V \; I  }\)

\(\large{ P_{out} = \frac{ p \; Q  }{ 8.5 }  }\)

 

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Tags: Efficiency Equations