1. What is Total Dynamic Head (TDH)?

Total Dynamic Head (TDH) is the total equivalent height that a fluid needs to be pumped, accounting for static lift, friction losses, and velocity head. It's a crucial parameter for proper pump selection and system design.

2. How Does the Calculator Work?

The calculator uses the TDH equation:

Where:

• \( H_{static} \) — Static head (vertical elevation difference)
• \( H_{friction} \) — Friction head loss in pipes and fittings
• \( H_{velocity} \) — Velocity head (kinetic energy component)
• \( v \) — Flow velocity (m/s)
• \( g \) — Gravitational acceleration (9.81 m/s²)

Explanation: The equation sums all energy requirements needed to move fluid through the system, converted to equivalent height (meters of fluid column).

3. Importance of TDH Calculation

Details: Accurate TDH calculation is essential for selecting a properly sized pump that can overcome system resistance and deliver required flow rates. Underestimating TDH leads to undersized pumps, while overestimating results in oversized, inefficient pumps.

4. Using the Calculator

Tips:

• Static head: Measure vertical distance from pump discharge to highest point in system
• Friction loss: Calculate using pipe size, length, material, and flow rate (or use tables/software)
• Velocity: Typically 1-3 m/s for water systems (higher for viscous fluids)

5. Frequently Asked Questions (FAQ)

Q1: When can velocity head be neglected?
A: In systems with low velocities (<1 m/s), velocity head is often negligible as it's typically <0.05 m.

Q2: How do I calculate friction loss?
A: Use Hazen-Williams or Darcy-Weisbach equations, or consult friction loss tables for your pipe material and diameter.

Q3: Does TDH change with flow rate?
A: Yes, friction loss increases with flow rate (approximately with the square of velocity), so TDH is flow-rate dependent.

Q4: What's typical TDH for residential systems?
A: For household water systems, TDH typically ranges 20-60 meters depending on elevation and piping.

Q5: How does fluid density affect TDH?
A: TDH is expressed in meters of fluid column, so it's independent of density for the calculator. However, pump power requirements do depend on density.