Pump Power Calculation kW

Pump Power Formula:

\[ P_e = \frac{Q \times H \times \rho \times 0.746}{3960 \times \eta} \]

Flow Rate (Q):

GPM

Head (H):

Density (ρ):

lb/gal

Efficiency (η):

Pump Power (P_e):

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1. What is Pump Power Calculation?

Definition: This calculator estimates the power required by a pump in kilowatts (kW) based on flow rate, head, fluid density, and pump efficiency.

Purpose: It helps engineers and technicians determine the appropriate pump size and power requirements for fluid systems.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ P_e = \frac{Q \times H \times \rho \times 0.746}{3960 \times \eta} \]

Where:

\( P_e \) — Pump power (kW)
\( Q \) — Flow rate (gallons per minute, GPM)
\( H \) — Total head (feet, ft)
\( \rho \) — Fluid density (pounds per gallon, lb/gal)
\( \eta \) — Pump efficiency (decimal, typically 0.6-0.85)

Explanation: The formula converts hydraulic power to mechanical power, accounting for pump efficiency.

3. Importance of Pump Power Calculation

Details: Accurate power calculation ensures proper pump selection, energy efficiency, and system reliability.

4. Using the Calculator

Tips: Enter flow rate in GPM, head in feet, fluid density (default 8.34 lb/gal for water), and pump efficiency (default 0.8). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the 0.746 factor in the formula?
A: This converts horsepower to kilowatts (1 HP = 0.746 kW).

Q2: What's a typical pump efficiency value?
A: Centrifugal pumps typically range from 60-85% efficiency (0.6-0.85).

Q3: How do I determine total head (H)?
A: Total head includes static head, friction losses, and pressure differences in the system.

Q4: What density should I use for other fluids?
A: For other fluids, use their specific weight divided by 7.48 (gallons per cubic foot).

Q5: Does this include motor efficiency?
A: No, this calculates pump shaft power. For electrical input power, divide by motor efficiency.