Enter head and daily water volume to size the pump, PV array and buffer tank. Water storage replaces the battery — the core of direct PV pumping — with a no-battery vs battery comparison.
The pump lifts the daily volume during peak-sun hours. Hydraulic power is P = ρ·g·Q·H; PV capacity = pump power ÷ (inverter efficiency × mismatch) × 1.2 safety margin. Over-pumping into a buffer tank stores energy as water, eliminating the battery.
100 m³/day Solar Water Pumping (30 m head, no battery)
Example 1 — 100 m³/day Solar Water Pumping (30 m head, no battery)
7.No-battery design stores energy as water; optional battery (37 kWh) only needed for night/overcast pumping.
📋 Design notes
Water storage = energy storage:The core of direct PV pumping is to over-pump during sunshine into an elevated/ground tank, so the water itself is the "battery". This eliminates battery CAPEX, replacement and round-trip losses — the key advantage over battery-buffered pumping.
PV matching (MPPT window):The array Vmp (≈40 V per 550 Wp module, strings in series) must sit inside the pump inverter MPPT window (200–800 V DC (typical pump inverter)) with ~15% headroom for the temperature coefficient of the modules.
No-battery vs battery:No-battery: 150 m³ tank (~1.5 days) supplies water overnight and through 1–2 cloudy days. Battery option (≈37 kWh) would run the pump at night instead, but costs more and adds maintenance — recommended only when a tank is impractical or land is scarce.
Pricing basis:PV modules, pump inverter and mounting are priced from the catalogue. Submersible pump, buffer tank, piping and sensors are quoted per project (POA) — pump price depends strongly on head, casing material and depth.
Daily supply & seasonal curve:The system delivers 100 m³/day at 5.5 PSH; seasonally it varies from ≈85 m³/day (winter) to ≈115 m³/day (summer). The 1.2× PV margin and 1.5× tank buffer absorb typical variability.
Operation & maintenance:Routine O&M: clean modules (soiling cuts output), inspect foot/check valves, check pump dry-run protection, verify earthing continuity and clean the tank annually. Pumps typically run maintenance-free for 5–10 years in clean water.
Design review:This is a preliminary sizing. Verify borehole yield, static/dynamic water level, total dynamic head (incl. pipe friction) and sand content before selecting the pump.
How it was calculated
Core formulas
Flow Q = daily volume ÷ (sun hours × 3600). Hydraulic power = 9.81 × Q × head. Pump power = hydraulic power ÷ η_pump. PV = pump power ÷ (0.95 × 0.90) × 1.2.
Direct PV pumping over-pumps into an elevated/ground tank during sunshine, so the water itself is the energy store. This removes battery CAPEX, replacement and round-trip losses — water storage is the key advantage of this approach.
When would I add a battery?
Only when a tank is impractical or land is scarce, to run the pump at night or through long overcast spells. The calculator shows the no-battery and battery options side by side.
How is PV capacity derived?
From the pump shaft power divided by inverter efficiency (0.95) and a mismatch factor (0.90), then ×1.2 safety margin to absorb irradiation variability.
What drives pump selection?
Head, daily volume and water source (well/river/reservoir) — deeper wells need multi-stage borehole pumps and more head. The pump and piping are quoted per project.
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Results are engineering estimates for reference. Final design must be confirmed by a licensed local engineer against site conditions and applicable codes. Prices are FOB Qingdao (EXW) and do not include freight, duty or installation.
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