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Solar Water Pump

PV capacity needed for a DC/AC solar pump.

Design

Inputs (SI units)

Total volume to be pumped per day (irrigation demand, livestock, domestic).

Duration the pump actually runs — sets the flow rate for hydraulic sizing.

Vertical distance from water surface to pump inlet (0 for submersible/flooded suction).

Vertical rise from pump to discharge point (tank, field head).

Combined suction + delivery pipe run length.

Sets flow velocity and friction loss — undersized pipe wastes energy.

Pipe roughness: PVC/HDPE ≈150, new steel ≈120, old galvanised ≈100.

Bends, valves, foot valve, strainer — typically 10–25% of straight-pipe friction loss.

Surface pumps are limited by practical suction lift (~7 m at sea level).

Efficiency of the pump end converting shaft power to hydraulic power.

PMSM/BLDC solar pump motors typically 85–92%.

MPPT pump controller / VFD conversion efficiency.

Site average daily peak sun hours (irradiance basis 1 kW/m²).

Soiling, temperature, mismatch and cabling losses applied to PV array sizing.

Results

PV array capacity (selected motor)
1.08 kWp
PV array capacity (theoretical)
1.05 kWp
Motor rating — selected standard
1 HP
Motor rating — theoretical
0.97 HP
Total dynamic head (TDH)
24.76 m
Friction head (Hazen-Williams)
0.662 m
Pipe velocity
0.71 m/s
Hydraulic power
0.337 kW
Electrical input power
0.726 kW
Daily electrical energy
4.36 kWh/day
✓ PASS — Pipe velocity 0.71 m/s is within the recommended 0.6–2.5 m/s band.
✓ PASS — Submersible pump selected — suction lift limit does not apply (pump is flooded).
✓ PASS — Total dynamic head 24.8 m is within normal solar pump range.
✓ PASS — Friction head is a modest 2.8% of static head.
✓ PASS — Selected motor (1 HP) is a tight, efficient match to the 0.97 HP requirement.

Engineering Recommendations

  • →Provide a dry-run protection sensor and float switch on both source and destination tanks.
  • →Use MPPT-based pump controllers to maximise energy harvest across the day.
  • →Verify submersible cable sizing separately for voltage drop at the required depth.
  • →Engineering-grade preliminary calculation. Final design must be verified against project-specific site conditions, manufacturer datasheets, applicable standards and utility requirements.

Detailed Calculation Log

Documented assumptions: ρ_water = 1000 kg/m³, g = 9.80665 m/s², Hazen-Williams SI coefficient 10.67, minor losses expressed as % of friction head.
Flow 5 m³/h through 50 mm submersible pipeline over 60 m.
Efficiency chain: pump 55% × motor 88% × VFD 96% = overall 46.5%.

Save & Load Project

Designs are stored privately in this browser — nothing is uploaded.

Engineering Formula

  • E_hydraulic = ρ × g × Q × H / 3.6×10⁶ [kWh/day]
  • E_electrical = E_hydraulic / η_pump
  • P_pv = E_electrical / (PSH × η_inv)

Hydraulic energy uses ρ=1000 kg/m³ and g=9.81 m/s². Electrical demand divides by combined pump+motor efficiency; PV capacity divides by PSH.

Step-by-step Calculation

  1. 1.Flow rateQ = V_daily / (t × 3600)0.00139 m³/s (5 m³/h)
  2. 2.Pipe velocityv = Q / A0.71 m/s
  3. 3.Static headH_static = suction + delivery24 m
  4. 4.Friction head (Hazen-Williams)hf = 10.67·L·Q^1.852 / (C^1.852·d^4.8704)0.662 m
  5. 5.Minor / fittings losses15% of hf0.099 m
  6. 6.Total dynamic headTDH = H_static + hf + minor24.76 m
  7. 7.Hydraulic powerP = ρ·g·Q·H0.337 kW
  8. 8.Shaft powerP_shaft = P_hyd / η_pump0.613 kW
  9. 9.Electrical input powerP_elec = P_shaft / (η_motor × η_vfd)0.726 kW
  10. 10.Daily electrical energyE = P_elec × t4.36 kWh/day
  11. 11.PV array (theoretical)P_pv = E / (PSH × derate)1.05 kWp
  12. 12.Motor rating (theoretical)HP = P_elec / 0.7460.97 HP
  13. 13.Motor rating (selected standard)nextStd(STD_PUMP_HP, 0.97)1 HP

How to use this calculator: Solar Water Pump

PV capacity needed for a DC/AC solar pump. The example below is calculated by this page's real engine from the displayed inputs.

  1. 1Confirm that the Solar Water Pump matches the quantity or design check you need.
  2. 2Enter Daily water requirement, Pumping hours per day, and Suction lift using the units printed beside each field.
  3. 3Select the applicable Pump type options; these choices change the calculation method or factors.
  4. 4Calculate, then follow the substituted equations in the worked example and compare the result with any stated limit.
  5. 5Read the assumptions, warnings and cited references before using the result for a financial, medical or engineering decision.

Input guide and example values

Use values from the same measurement basis and time period. Conditional fields appear only when the related option is selected.

InputExample valueWhy it matters
Daily water requirement30 m³/dayTotal volume to be pumped per day (irrigation demand, livestock, domestic).
Pumping hours per day6 hDuration the pump actually runs — sets the flow rate for hydraulic sizing.
Suction lift4 mVertical distance from water surface to pump inlet (0 for submersible/flooded suction).
Delivery / static height20 mVertical rise from pump to discharge point (tank, field head).
Total pipe length60 mCombined suction + delivery pipe run length.
Pipe internal diameter50 mmSets flow velocity and friction loss — undersized pipe wastes energy.
Hazen-Williams C-factor150Pipe roughness: PVC/HDPE ≈150, new steel ≈120, old galvanised ≈100.
Minor/fittings losses15 % of friction headBends, valves, foot valve, strainer — typically 10–25% of straight-pipe friction loss.
Pump typeSubmersibleSurface pumps are limited by practical suction lift (~7 m at sea level).
Pump hydraulic efficiency55 %Efficiency of the pump end converting shaft power to hydraulic power.
Motor efficiency88 %PMSM/BLDC solar pump motors typically 85–92%.
Controller / VFD efficiency96 %MPPT pump controller / VFD conversion efficiency.
Peak sun hours5.2 hSite average daily peak sun hours (irradiance basis 1 kW/m²).
System derate factor80 %Soiling, temperature, mismatch and cabling losses applied to PV array sizing.

Formula inputs & variables for Solar Water Pump

These are the named quantities used by this calculator. When the source formula does not define a mathematical symbol, OneCalcApp keeps the real input label instead of inventing one.

Variable / inputUnitMeaning in this calculation
Daily water requirementm³/dayTotal volume to be pumped per day (irrigation demand, livestock, domestic).
Pumping hours per dayhDuration the pump actually runs — sets the flow rate for hydraulic sizing.
Suction liftmVertical distance from water surface to pump inlet (0 for submersible/flooded suction).
Delivery / static heightmVertical rise from pump to discharge point (tank, field head).
Total pipe lengthmCombined suction + delivery pipe run length.
Pipe internal diametermmSets flow velocity and friction loss — undersized pipe wastes energy.
Hazen-Williams C-factor—Pipe roughness: PVC/HDPE ≈150, new steel ≈120, old galvanised ≈100.
Minor/fittings losses% of friction headBends, valves, foot valve, strainer — typically 10–25% of straight-pipe friction loss.

How the Solar Water Pump works

The Solar Water Pump uses Daily water requirement, Pumping hours per day, Suction lift, Delivery / static height, Total pipe length, Pipe internal diameter, Hazen-Williams C-factor, Minor/fittings losses, Pump type, Pump hydraulic efficiency, Motor efficiency, Controller / VFD efficiency, Peak sun hours, and System derate factor to calculate PV array capacity (selected motor), PV array capacity (theoretical), Motor rating — selected standard, Motor rating — theoretical, Total dynamic head (TDH), Friction head (Hazen-Williams), Pipe velocity, Hydraulic power, Electrical input power, and Daily electrical energy. Its engine applies E_hydraulic = ρ × g × Q × H / 3.6×10⁶ [kWh/day]; the worked values below come from that same live calculation rather than a separately typed example.

With Daily water requirement 30 m³/day, Pumping hours per day 6 h, Suction lift 4 m, Delivery / static height 20 m, Total pipe length 60 m, Pipe internal diameter 50 mm, Hazen-Williams C-factor 150, Minor/fittings losses 15 % of friction head, Pump type Submersible, Pump hydraulic efficiency 55 %, Motor efficiency 88 %, Controller / VFD efficiency 96 %, Peak sun hours 5.2 h, and System derate factor 80 %, the main worked-example result is PV array capacity (selected motor) = 1.08 kWp.

How each Solar Water Pump input is used

Daily water requirement

The Solar Water Pump worked example uses Daily water requirement = 30 m³/day. This value is passed directly into the calculation, with an allowed minimum 0.1. Total volume to be pumped per day (irrigation demand, livestock, domestic).

Pumping hours per day

The Solar Water Pump worked example uses Pumping hours per day = 6 h. This value is passed directly into the calculation, with an allowed minimum 0.5 and maximum 16. Duration the pump actually runs — sets the flow rate for hydraulic sizing.

Suction lift

The Solar Water Pump worked example uses Suction lift = 4 m. This value is passed directly into the calculation, with an allowed minimum 0. Vertical distance from water surface to pump inlet (0 for submersible/flooded suction).

Delivery / static height

The Solar Water Pump worked example uses Delivery / static height = 20 m. This value is passed directly into the calculation, with an allowed minimum 0. Vertical rise from pump to discharge point (tank, field head).

Total pipe length

The Solar Water Pump worked example uses Total pipe length = 60 m. This value is passed directly into the calculation, with an allowed minimum 1. Combined suction + delivery pipe run length.

Pipe internal diameter

The Solar Water Pump worked example uses Pipe internal diameter = 50 mm. This value is passed directly into the calculation, with an allowed minimum 10 and maximum 300. Sets flow velocity and friction loss — undersized pipe wastes energy.

Hazen-Williams C-factor

The Solar Water Pump worked example uses Hazen-Williams C-factor = 150. This value is passed directly into the calculation, with an allowed minimum 80 and maximum 160. Pipe roughness: PVC/HDPE ≈150, new steel ≈120, old galvanised ≈100.

Minor/fittings losses

The Solar Water Pump worked example uses Minor/fittings losses = 15 % of friction head. This value is passed directly into the calculation, with an allowed minimum 0 and maximum 60. Bends, valves, foot valve, strainer — typically 10–25% of straight-pipe friction loss.

Pump type

The Solar Water Pump worked example selects “Submersible”. Available choices include Submersible and Surface / centrifugal. This selection may change the method or factor used by the engine, so choose the option that matches the real case.

Pump hydraulic efficiency

The Solar Water Pump worked example uses Pump hydraulic efficiency = 55 %. This value is passed directly into the calculation, with an allowed minimum 20 and maximum 80. Efficiency of the pump end converting shaft power to hydraulic power.

Motor efficiency

The Solar Water Pump worked example uses Motor efficiency = 88 %. This value is passed directly into the calculation, with an allowed minimum 50 and maximum 97. PMSM/BLDC solar pump motors typically 85–92%.

Controller / VFD efficiency

The Solar Water Pump worked example uses Controller / VFD efficiency = 96 %. This value is passed directly into the calculation, with an allowed minimum 80 and maximum 99. MPPT pump controller / VFD conversion efficiency.

Peak sun hours

The Solar Water Pump worked example uses Peak sun hours = 5.2 h. This value is passed directly into the calculation, with an allowed minimum 1 and maximum 9. Site average daily peak sun hours (irradiance basis 1 kW/m²).

System derate factor

The Solar Water Pump worked example uses System derate factor = 80 %. This value is passed directly into the calculation, with an allowed minimum 50 and maximum 95. Soiling, temperature, mismatch and cabling losses applied to PV array sizing.

Solar Water Pump formulas and result interpretation

Formula 1: relationship used

In the Solar Water Pump, E_hydraulic = ρ × g × Q × H / 3.6×10⁶ [kWh/day]. The quantities in this relationship come from the named inputs or from an earlier calculation step shown in the worked example.

Formula 2: relationship used

In the Solar Water Pump, E_electrical = E_hydraulic / η_pump. The quantities in this relationship come from the named inputs or from an earlier calculation step shown in the worked example.

Formula 3: relationship used

In the Solar Water Pump, P_pv = E_electrical / (PSH × η_inv). The quantities in this relationship come from the named inputs or from an earlier calculation step shown in the worked example.

PV array capacity (selected motor)

For the displayed Solar Water Pump worked example, PV array capacity (selected motor) is 1.08 kWp. Verify Daily water requirement, Pumping hours per day, and Suction lift and their units before relying on this output.

PV array capacity (theoretical)

For the displayed Solar Water Pump worked example, PV array capacity (theoretical) is 1.05 kWp. Verify Daily water requirement, Pumping hours per day, and Suction lift and their units before relying on this output.

Motor rating — selected standard

For the displayed Solar Water Pump worked example, Motor rating — selected standard is 1 HP. Verify Daily water requirement, Pumping hours per day, and Suction lift and their units before relying on this output.

Motor rating — theoretical

For the displayed Solar Water Pump worked example, Motor rating — theoretical is 0.97 HP. Verify Daily water requirement, Pumping hours per day, and Suction lift and their units before relying on this output.

Total dynamic head (TDH)

For the displayed Solar Water Pump worked example, Total dynamic head (TDH) is 24.76 m. Verify Daily water requirement, Pumping hours per day, and Suction lift and their units before relying on this output.

Friction head (Hazen-Williams)

For the displayed Solar Water Pump worked example, Friction head (Hazen-Williams) is 0.662 m. Verify Daily water requirement, Pumping hours per day, and Suction lift and their units before relying on this output.

Pipe velocity

For the displayed Solar Water Pump worked example, Pipe velocity is 0.71 m/s. Verify Daily water requirement, Pumping hours per day, and Suction lift and their units before relying on this output.

Hydraulic power

For the displayed Solar Water Pump worked example, Hydraulic power is 0.337 kW. Verify Daily water requirement, Pumping hours per day, and Suction lift and their units before relying on this output.

Electrical input power

For the displayed Solar Water Pump worked example, Electrical input power is 0.726 kW. Verify Daily water requirement, Pumping hours per day, and Suction lift and their units before relying on this output.

Daily electrical energy

For the displayed Solar Water Pump worked example, Daily electrical energy is 4.36 kWh/day. Verify Daily water requirement, Pumping hours per day, and Suction lift and their units before relying on this output.

Solar Water Pump accuracy, checks and limitations

  • Solar Water Pump units check: confirm Daily water requirement (m³/day), Pumping hours per day (h), Suction lift (m), Delivery / static height (m), Total pipe length (m), Pipe internal diameter (mm), Hazen-Williams C-factor, Minor/fittings losses (% of friction head), Pump type, Pump hydraulic efficiency (%), Motor efficiency (%), Controller / VFD efficiency (%), Peak sun hours (h), and System derate factor (%) before calculating.
  • Solar Water Pump result check: compare PV array capacity (selected motor), PV array capacity (theoretical), Motor rating — selected standard, Motor rating — theoretical, Total dynamic head (TDH), Friction head (Hazen-Williams), Pipe velocity, Hydraulic power, Electrical input power, and Daily electrical energy with the substituted formula steps and the displayed rounding precision.
  • Solar Water Pump: Use this result for preliminary design and cross-checking. Confirm the applicable code edition, manufacturer data, site conditions and qualified-engineer approval before final design or installation.

Understanding the result

Read the main result together with supporting checks, assumptions, limits and intermediate values.

For a manual check, repeat the first equation, confirm the units and change one input at a time.

Common mistakes when using Solar Water Pump

  • Do not mix units for Daily water requirement (m³/day), Pumping hours per day (h), Suction lift (m). A unit mismatch changes the input magnitude even when the typed number looks reasonable.
  • Do not leave Pump type on the default choice unless that choice matches the real scenario; the selected option can change the calculation path or factor.
  • Do not replace the displayed E_hydraulic = ρ × g × Q × H / 3.6×10⁶ [kWh/day] relationship with a different convention without also changing the underlying assumptions; compare like-for-like methods when checking the result.
  • Do not treat PV array capacity (selected motor) = 1.08 kWp from the worked example as a universal answer. It belongs to the displayed example inputs and must be recalculated for the actual case.

When the Solar Water Pump is useful

Solar Water Pump is designed for cases where Daily water requirement, Pumping hours per day, Suction lift, Delivery / static height are known and you need PV array capacity (selected motor), PV array capacity (theoretical), Motor rating — selected standard. The page keeps the live calculator, calculation method and worked example together so the result can be checked instead of treated as a black-box number.

Use the calculator for the scope described by its inputs and notes. The displayed method is E_hydraulic = ρ × g × Q × H / 3.6×10⁶ [kWh/day]. If the real project or decision needs factors that are not represented here, treat the result as an estimate and add the missing checks separately.

Daily water requirement and Pumping hours per day: what changes the answer

The worked example uses Daily water requirement = 30 m³/day, Pumping hours per day = 6 h, Suction lift = 4 m, Delivery / static height = 20 m. With those values, PV array capacity (selected motor) is 1.08 kWp. Changing an input should be interpreted according to that field's unit, range, option and hint rather than by the number alone.

For this calculator, the main input roles are: Daily water requirement (m³/day): Total volume to be pumped per day (irrigation demand, livestock, domestic). Pumping hours per day (h): Duration the pump actually runs — sets the flow rate for hydraulic sizing. Suction lift (m): Vertical distance from water surface to pump inlet (0 for submersible/flooded suction). Delivery / static height (m): Vertical rise from pump to discharge point (tank, field head).

How to sanity-check a Solar Water Pump result

Start by confirming the entered values and units, then compare the substituted working with the displayed formula or calculation steps. Pay particular attention to PV array capacity (selected motor), because it is the first worked-example output shown by the live engine.

Finally, compare the result with the assumptions, warnings and related calculators on this page. A nearby calculator can be useful as a cross-check when it measures the same workflow from a different input or output direction.

Next logical calculator

Continue with Farm Water Requirement Calculator

Useful next check because both tools use Daily water requirement, while Farm Water Requirement Calculator answers a different part of the same workflow.

Open Farm Water Requirement Calculator

Standards, source trail and limitations

References show the method used. Check the current local edition, amendments and project specification before a regulated decision.

Design Assumptions

  • • Water density 1000 kg/m³.
  • • Inverter/VFD efficiency 96%.

Engineering Tips

  • ◆Add 20% margin for cloudy days and pipe friction.
  • ◆Use MPPT VFD drives for AC submersibles.

Warnings

  • ▲Never dry-run submersible motors — install level sensors.

Standards & References

IS 8034 (Submersible pumps)IEC 62253

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