Solar Water Pumping
How Solar Borehole Pumping Systems Are Sized
A solar borehole system should be designed from the water requirement and hydraulic duty before the pump or number of solar panels is selected.
Begin with water demand
The required litres per day determine how much water the system must deliver during the available pumping period. Storage tanks can allow the pump to operate mainly during daylight hours.
Calculate the actual pumping head
Borehole depth alone is not total dynamic head. Pumping water level, elevation to the delivery point, tank height and friction losses through the pipework all affect the pressure the pump must overcome.
- ●Pumping water level
- ●Elevation difference
- ●Tank height or required pressure
- ●Pipe length
- ●Pipe diameter
- ●Fittings and friction losses
Match the pump curve
The selected pump should deliver the required flow at the calculated head within a suitable operating region of the manufacturer's performance curve.
Once the pump and motor are selected, the solar array and pumping controller can be sized around their electrical requirements and available solar resource.
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