Analyze fan performance using fan laws, system curves, and power calculations
New Flow Rate
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CFM
New Pressure
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in WC
New Power
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HP
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-
-
-
-
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kWh/year
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at $0.12/kWh
75%
90%
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The fan laws describe how fan performance changes with speed, diameter, and density.
The system curve represents the pressure required to move air through a duct system.
Calculate fan power requirements and energy consumption for cost analysis.
Q₂/Q₁ = (N₂/N₁) × (D₂/D₁)³ P₂/P₁ = (N₂/N₁)² × (D₂/D₁)² × (ρ₂/ρ₁) W₂/W₁ = (N₂/N₁)³ × (D₂/D₁)⁵ × (ρ₂/ρ₁)
ΔP = SP + K·Q² where ΔP is total pressure, SP is static pressure at zero flow, K is system resistance coefficient, and Q is flow rate. The operating point is where the fan curve intersects the system curve.
P = (Q × P) / (6356 × ηfan × ηmotor) where Q is flow in CFM, P is pressure in inches WC, and η are efficiencies as decimals.