Calculate Pump Efficiency Formula

Pump Efficiency Formula:

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

Density (ρ):

kg/m³

Flow Rate (Q):

m³/s

Head (H):

Shaft Power (P_s):

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 supplied to the pump shaft. It measures how effectively a pump converts input power into useful fluid flow and pressure.

2. How Does the Calculator Work?

The calculator uses the pump efficiency formula:

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

Where:

\( \eta \) — Pump efficiency (unitless, 0 to 1)
\( \rho \) — Fluid density (kg/m³)
\( g \) — Gravitational acceleration (9.81 m/s²)
\( Q \) — Volumetric flow rate (m³/s)
\( H \) — Total dynamic head (m)
\( P_s \) — Shaft power input (W)

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 system performance evaluation. Higher efficiency means less energy waste and lower operating costs.

4. Using the Calculator

Tips: Enter all values in the specified units. Density is typically 1000 kg/m³ for water. Flow rate should be in m³/s (convert from L/s by dividing by 1000). Head is the total dynamic head in meters.

5. Frequently Asked Questions (FAQ)

Q1: What is a good pump efficiency value?
A: Centrifugal pumps typically range from 40-85% efficiency. Values above 70% are generally considered good for most applications.

Q2: Why might pump efficiency be low?
A: Causes include incorrect sizing, wear, cavitation, improper speed, or high system resistance. Regular maintenance can help maintain efficiency.

Q3: How does viscosity affect pump efficiency?
A: Higher viscosity generally reduces efficiency as more energy is lost to friction. Special pumps are needed for highly viscous fluids.

Q4: Can efficiency exceed 100%?
A: No, this would violate energy conservation laws. If calculation shows >100%, check for measurement errors in power, flow, or head.

Q5: How often should pump efficiency be checked?
A: For critical applications, monitor continuously. For others, periodic testing (e.g., annually) is recommended, or whenever performance issues are suspected.