Matched pressure and efficiency required
Fan Shaft Power Estimate
Estimate air power and fan shaft power at one documented operating point. The selected pressure basis must match the efficiency basis; motor electrical input and motor selection are not calculated.
Operating-point power estimate
For a matched pressure/efficiency basis,the air-power magnitude is Pair=QΔp W and the estimated fan shaft power is P轴=QΔp/η W. Thus with Q in m³/s and Δp in Pa,the result is watts because Pa·m³/s=N·m/s=W.
The U.S. Department of Energy fan test-procedure material distinguishes static air power for relevant unducted configurations from total air power for ducted configurations. Mixing pressure and efficiency definitions creates a physically inconsistent estimate.
The official ISO catalogue lists ISO5801:2017,edition3 as Published but to be revised,with Amendment1:2025 and a replacement project under development. It governs fan performance testing using standardized airways;this simple calculation is not an ISO5801 test or certified conversion.
Mechanical horsepower uses the NIST SP811 value 1hp(550ft·lbf/s)=745.6999W. “hp” here is not metric horsepower or electrical horsepower.
No universal efficiency or motor factor: the removed fan-type efficiency ranges and 1.15–1.25 motor multiplier were not adequate for selection. Use the certified fan curve/test point,drive and motor efficiencies,service factor,duty,starting/overload behavior,ambient/temperature,applicable electrical code and manufacturer data.
资料来源：DOE fan/blower test-procedure material;ISO5801 status/scope;NIST power conversions.
