Pump Curve Efficiency Calculator

Pump Efficiency Equation:

\[ \eta = \frac{\rho \times g \times Q \times H}{P_s} \]

Fluid Density (ρ):

kg/m³

Flow Rate (Q):

m³/s

Head (H):

meters

Shaft Power (P_s):

Watts

Pump Efficiency (η):

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1. What is Pump Efficiency?

Pump efficiency (η) is the ratio of hydraulic power delivered to the fluid to the mechanical power input to the pump shaft. It indicates how effectively a pump converts mechanical energy into fluid flow energy.

2. How Does the Calculator Work?

The calculator uses the pump efficiency equation:

\[ \eta = \frac{\rho \times g \times Q \times H}{P_s} \]

Where:

\( \eta \) — Pump efficiency (unitless, 0 to 1)
\( \rho \) — Fluid density (kg/m³)
\( g \) — Acceleration due to gravity (9.81 m/s²)
\( Q \) — Volumetric flow rate (m³/s)
\( H \) — Head (meters)
\( P_s \) — Shaft power input (Watts)

Explanation: The numerator represents the hydraulic power delivered to the fluid, while the denominator is the mechanical power input to the pump.

3. Importance of Pump Efficiency

Details: Pump efficiency is crucial for energy conservation, operating cost reduction, and proper pump selection. Higher efficiency means less energy is wasted as heat and vibration.

4. Using the Calculator

Tips: Enter all values in the specified units. Ensure density is positive, flow rate is positive, head is positive, and shaft power is positive. The calculator will return efficiency as a percentage (0-100%).

5. Frequently Asked Questions (FAQ)

Q1: What is a good pump efficiency value?
A: Centrifugal pumps typically range from 40-85% efficiency. Positive displacement pumps can reach 90% or more. Efficiency depends on pump type, size, and operating conditions.

Q2: Why does efficiency matter?
A: Pumps account for ~20% of global electrical energy use. A 10% improvement in efficiency can lead to significant energy savings over a pump's lifetime.

Q3: How does efficiency vary with flow rate?
A: Pumps have a best efficiency point (BEP) where they operate most efficiently. Efficiency drops at higher or lower flow rates than the BEP.

Q4: What affects pump efficiency?
A: Factors include impeller design, wear, operating point relative to BEP, fluid viscosity, and system resistance.

Q5: Can efficiency exceed 100%?
A: No, efficiency is always ≤1 (100%). Values >100% indicate measurement errors or incorrect assumptions.