1. What is the Pump Power Equation?

The pump power equation calculates the required horsepower for a water pump based on flow rate, total head, specific gravity, and pump efficiency. This is essential for proper solar water pump system design.

2. How Does the Calculator Work?

The calculator uses the pump power equation:

Where:

• \( Q \) — Flow rate in gallons per minute (GPM)
• \( H \) — Total head in feet
• \( SG \) — Specific gravity (1.0 for water)
• \( \eta \) — Pump efficiency (typically 0.5-0.8)
• 3960 — Conversion factor (foot-pounds per minute to horsepower)

Explanation: The equation calculates the power needed to move a given volume of liquid against a specific head pressure, accounting for pump efficiency.

3. Importance of Proper Pump Sizing

Details: Correct pump sizing ensures efficient operation, prevents energy waste, and extends equipment life. Undersized pumps won't meet demand, while oversized pumps waste energy and money.

4. Using the Calculator

Tips: Enter flow rate in GPM, total head in feet, specific gravity (1 for water), and pump efficiency as a decimal (e.g., 70% = 0.7). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is total head?
A: Total head is the vertical distance the water must be pumped plus friction losses in pipes, measured in feet.

Q2: What's a typical pump efficiency?
A: Centrifugal pumps typically range from 50-80% efficiency. Check manufacturer specifications for exact values.

Q3: How does this relate to solar panel sizing?
A: The calculated HP must be converted to watts (1 HP ≈ 746W) and divided by solar panel output to determine required solar array size.

Q4: What about intermittent operation?
A: Solar pumps often run only during daylight. Storage tanks can compensate for intermittent operation.

Q5: Should I add a safety factor?
A: Yes, typically add 10-20% to the calculated HP to account for system losses and future needs.