Solar Water Pump Size Calculator & Borehole Sizing

Daily irrigation volume is field area × net application depth / application efficiency; direct-volume mode uses the entered delivered volume. The sizing factor multiplies this daily requirement. The demand/head/solar-resource workflow follows the GIZ/FAO SPIS DESIGN module, section 5 (PDF p.14).

The head model is $H(Q)=H_s+z_{delivery}+p/(\rho g)+s(Q)+h_f(Q)$. Measured drawdown is scaled as $s(Q)=s_{test}Q/Q_{test}$, the steady-state form of the PVsyst borehole model. The level is depth below ground, so the pump intake is checked separately against this level plus the required submergence.

The pipe functions are reused from WiredWhite's Pipe Pressure Drop and Pump Sizing calculator: $h_f=(fL/D+\Sigma K)v^2/(2g)$ with $v=Q/A$. Darcy $f=64/Re$ for $Re\le2000$; Colebrook–White is iterated 14 times above Re=4000, starting from Swamee–Jain. Between 2000 and 4000 a linear blend is only an estimate. At zero flow losses and the displayed factor are zero.

The sun is a half-sine over the entered daylight window, normalized so its time integral equals peak sun hours. Available DC power is PV nameplate × field factor × normalized irradiance. A 241-point hydraulic-load curve is inverted at 121 daylight samples. A root solver adjusts PV rating until integrated flow meets the daily target. $P_h=\rho gQH$, shaft power is $P_h/\eta_p$, and motor input is shaft power divided by motor efficiency. Peak ratings and daily trapezoidal integrals are reported separately.

The numerical sun profile and inversion are derived here from energy balance; they are not a pump manufacturer's performance prediction. The CDER 2008 ideal-head example and Penn State pipe-loss example verify the energy and friction paths independently. Original diagrams are schematic.

Historical finance uses the lesser of entered tender and benchmark costs, multiplied by the selected 2024 central and minimum-state shares. Owner cost is tender cost less those grants, before loans. MNRE guidelines (https://upnedakusumc2.in/assets/Policy/Policy2.pdf), attached pp.8–10, govern these snapshots.

Fresh, incompressible Newtonian water; constant properties and a single equivalent circular pipe. The user supplies pipe roughness and fittings. Enter K≈1 for a submerged pipe exit into a large open tank, and include terminal velocity head for a free jet through its equivalent K.

A variable-speed MPPT controller can operate across the whole modelled power range, without a start threshold, minimum speed or power clipping. Pump, motor and controller efficiencies and the field output factor are constant. Thus the calculated PV rating is a screening minimum for the selected water allowance, not a guaranteed daily yield.

Drawdown is linear with pumping rate and follows the changing flow immediately. This approximation omits transient aquifer storage, well-loss nonlinearity, recovery lag and nearby pumping. Above-test flow is flagged. Use the lowest seasonal static level and a separately verified sustainable rate. The animation shows this assumed daily response, not a measured transient.

Nominal defaults represent about 20 °C water and a smooth plastic pipe; they are editable assumptions. The default 3 m minimum submergence is an input assumption. Physical values use explicit units with the platform's metric/US display and input unit chooser; a second peak-flow card gives US gallons per minute. Diagram labels stay in the stated SI units. Horsepower is mechanical hp.

A general 2024 Component B snapshot uses central/state fractions 0.30/0.30; special-region snapshot 0.50/0.30; general central-only snapshot 0.30/0. Larger state grants, loans, taxes and other incentives are excluded. Costs must be for the agency-approved eligible category.

Use for preliminary sizing of a submersible solar water supply or irrigation pump with positive static lift. The whole-day profile is conditional on sufficient borehole yield, water cover and a compatible variable-speed pump map. A failed borehole warning means the displayed design day is infeasible; the model does not silently limit flow to make the result look acceptable.

Obtain a pumping test over the intended flow and duration, sustainable abstraction advice, manufacturer curves and site-specific design-month irradiation before procurement. Linear drawdown can underpredict losses at high flow; short-term specific capacity does not prove annual recharge. Direct irrigation pressure can vary with zoning and filters; enter the worst relevant duty or model those circuits separately.

No pump-model selection, electrical string/cable/protection design, surge calculation, NPSH certification, borehole screen design or weather reliability guarantee is included. Surface suction pumps require a separate NPSH/suction-lift assessment. The night-only storage lower bound omits intra-day mismatch and cloudy-day reserve.

PM-KUSUM presets are historical rules dated 17 January 2024, not current application advice. The ordinary CFA category is capped at 7.5 HP; specified special regions have a quota-limited provision up to 15 HP. Larger pumps need an approved capped cost base. The 2024 PV limit is 1 kW per nameplate HP. Confirm all category, domestic-content, groundwater-zone and current programme conditions with the state agency. Check against the electrical rules and standards in force. Installation work belongs to a qualified person.