Calculator Inputs
Example Data Table
| Case | Flow Rate (m³/s) | Gross Head (m) | Head Loss (m) | Turbine Eff. (%) | Generator Eff. (%) | Mechanical Eff. (%) | Electrical Output (kW) | Annual Energy (MWh) |
|---|---|---|---|---|---|---|---|---|
| Reference Plant | 18.00 | 52.00 | 4.00 | 91.00 | 96.00 | 99.00 | 7,330.45 | 43,982.69 |
| Compact Site | 4.50 | 34.00 | 2.00 | 88.00 | 95.00 | 98.00 | 1,170.92 | 7,025.52 |
| High Head Site | 7.20 | 120.00 | 8.00 | 92.00 | 97.00 | 99.00 | 6,981.25 | 48,868.75 |
Formula Used
Net Head: Net Head = Gross Head − Head Loss
Hydraulic Power: Phyd = ρ × g × Q × Hnet
Shaft Power: Pshaft = Phyd × ηturbine
Electrical Power: Pelec = Pshaft × ηgenerator × ηmechanical
Penstock Area: A = π × D² / 4
Water Velocity: V = Q / A
Velocity Head: hv = V² / (2g)
Annual Energy: E = Pelec(kW) × Operating Hours
Specific Speed: Ns = N × √P / H1.25
ρ is water density, g is gravity, Q is flow rate, and H is net head.
How to Use This Calculator
- Select metric or imperial input mode.
- Enter site flow, gross head, and estimated head loss.
- Add penstock diameter to estimate velocity and velocity head.
- Enter turbine, generator, and mechanical efficiencies.
- Provide annual operating hours for yearly energy output.
- Optional runner speed helps estimate specific speed.
- Press Calculate Power to display results above the form.
- Use the CSV and PDF buttons to save results.
FAQs
1. What does this calculator estimate?
It estimates hydro turbine net head, hydraulic power, shaft power, electrical output, annual energy, velocity head, and specific speed from site and equipment inputs.
2. Why is net head lower than gross head?
Net head subtracts hydraulic losses from the gross elevation difference. Friction, bends, valves, and intake conditions reduce usable head before water reaches the runner.
3. Why are efficiency inputs separated?
Separate efficiency fields show where energy is lost. Turbine, generator, and mechanical losses do not occur at the same stage, so splitting them improves design transparency.
4. Can I use imperial units?
Yes. Choose imperial mode to enter flow in cubic feet per second and head or diameter in feet. The calculator converts values internally.
5. What is velocity head used for?
Velocity head expresses the kinetic energy of moving water as an equivalent head term. It helps engineers review flow conditions inside the penstock.
6. What does specific speed indicate?
Specific speed helps compare runner types and speed behavior across designs. It is useful during turbine selection and preliminary performance screening.
7. Why is annual energy important?
Power shows instantaneous capability, while annual energy reflects practical generation over time. Investors and planners often use yearly energy to assess revenue potential.
8. Is this enough for final plant design?
No. It is a strong preliminary tool. Final design should also include seasonal flow duration, cavitation review, structural checks, controls, and detailed hydraulic modeling.