Fan Air Power Calculator

How the fan air power calculator works

Air power in kW = actual cubic metres per second × pressure rise in Pa ÷ 1,000. Divide by fan efficiency fraction for estimated shaft power, then by motor efficiency fraction for estimated electrical input. Both efficiencies must be positive and no more than 100%.

The pressure and fan efficiency must use the same total/static convention. Actual inlet flow is different from standard-condition gas volume. The low-pressure effectively incompressible relation excludes compressibility corrections and does not select a fan, approve ventilation, establish a motor rating or determine a safe duty.

Quantities use the stated units and finite bounded inputs. Whole purchases round up under the documented model; cost components round half-up to cents before totals are summed. Undefined ratios stay unavailable. π and logarithms use normal numeric precision. Display rounding does not alter the entered assumptions.

Worked example

2 m³/s at 500 Pa represents 1 kW air power. At 80% fan and 90% motor efficiency, estimated shaft and electric inputs are 1.25 and about 1.389 kW. Doubling flow to 4 m³/s doubles air power to 2 kW.

Sources and assumptions

The source material explains the underlying calculation or pricing structure. Entered prices, costs, schedules and scenario choices are your assumptions; this tool does not obtain supplier quotes or predict actual results.

• DOE Fan System Performance sourcebook