Irrigation is one of the most natural uses for solar pumping. Solar availability may align with some daytime pumping needs, while irrigation schedules depend on crop requirements, weather and the site. A suitably sized dam or tank can store pumped water for later use. This guide looks at the main irrigation arrangements and where solar pumping, variable speed drives and control equipment fit.
Why Solar Suits Irrigation
Solar availability can align well with daytime irrigation demand, but watering schedules, seasonal weather and crop requirements must be assessed. Water storage can help separate the pumping schedule from the irrigation schedule. A solar pump inverter can operate a compatible electric pump motor from a suitably designed PV array without batteries.
Common Arrangements
- Borehole to tank or dam: the solar pump fills storage, and gravity or a second pump feeds the fields.
- Dam or river to field transfer: a surface pump moves water directly to the lands.
- Direct to drip or sprinkler: the pump supplies pressure directly to the irrigation system.
Storage Versus Direct Pumping
Pumping into storage allows transfer-pump output to vary with sunlight while irrigation follows its own schedule. However, a tank does not automatically provide sufficient or steady pressure. Usable gravity pressure depends on elevation and water level, after pipe and fitting losses; a booster pump may be needed.
Direct solar pumping into irrigation can work where the pump, zoning and controls meet the required duty under changing power. Below the necessary pressure or flow, irrigation quality can suffer. Include low-pressure or low-flow stop logic and a plan for periods when solar power is insufficient.
Pressure Requirements
Drip systems, micro-sprinklers and pivots each need a particular operating pressure and flow. The pump, the pipework and the control must be sized to deliver it. Friction losses in long pipelines can be significant and should be part of the total head calculation.
Constant Pressure With a VSD
Browse our VSD collection for motor-control equipment and our solar pump inverter collection for direct-PV pump-drive options.
A compatible VSD and pressure transmitter can regulate a booster pump towards a pressure setpoint. The pump must have sufficient capacity and adequate power available: speed control cannot maintain pressure when sunlight, supply capacity or water availability is inadequate.
Confirm minimum flow, pump operating limits, sensor range, sleep/wake settings and dry-run protection. Grid, generator or power-inverter supplies must suit the drive's input and electrical characteristics; do not assume every inverter or generator is compatible.
Hybrid Systems
An AC-capable solar pump drive may allow grid or generator backup. Manual transfer, automatic transfer and concurrent AC/PV operation depend on the model and the manufacturer's approved wiring and control arrangement. Confirm the switching equipment and interlocks before specifying a hybrid system. Do not connect sources together on the assumption that the drive manages them automatically.
Control and Automation
Our PLC collection and remote I/O and automation modules collection include control hardware to assess for the required signals and sequence.
A simple system may need nothing more than a float switch. Larger systems often benefit from a PLC or pump controller that handles:
- Tank and dam level control
- Duty and standby pumps
- Valve sequencing for different lands
- Alarms for dry run, high pressure or low level
Remote Monitoring
Lands and dams are often far from the homestead. An LTE router and basic telemetry allow you to see pump status, tank level and alarms remotely. See our article on remote monitoring for boreholes and dams.
Protection and Enclosures
Outdoor panels face sun, dust and sometimes rodents and insects. Choose a suitable enclosure, add DC isolation and surge protection, earth the system correctly and use proper glands and cable protection.
Planning Checklist
- Water source, yield and storage size
- Daily water requirement and peak demand
- Required flow and pressure at the lands
- Pipe length, diameter and elevation changes
- Pump and motor details
- Power source: solar only, hybrid, grid or generator
- Control and monitoring needs
- Enclosure location and site conditions
Technical Note
This article gives general information only. Hydraulic design, pump selection, electrical protection and installation must be assessed for the specific site in accordance with manufacturer documentation and applicable standards, and carried out by competent persons.
Related catalogue examples: Solar Pump Inverters | Variable Speed Drives | Custom Control Panels. For an equipment enquiry, contact Softcore Group Industrial Solutions at info@softcoregroup.co.za.
Technical Resources
- VEICHI SI23 manufacturer information
- VEICHI SI21 manufacturer information
- Slanvert Hope65-SPD manufacturer information
- Technical resources and manuals
Use the documentation for the exact supplied model and revision. Family documents can cover ratings and options that do not apply to every unit.