Before going into the working of a solar water pump, let’s look at what they are.
Solar water pumps are those that work on the electricity produced from solar panels as opposed to conventional pumps that work on grid electricity. These pumps are powered by matching solar modules with power rating equivalent to that required by the pumps. Solar water pumps are a good idea in places with abundant sunshine and also where the needs can be supplied by the electricity produced by the panels.
Now, coming to how solar water pumps work.
Solar water pumping systems comprise of the following:
- Solar panels
The solar panels convert the sunlight falling on them into direct current electricity. Here the size of the PV systems depends on the rating of the pump, the amount of water that needs to be pumped and the amount of sunshine in the area.
The controller now acts as the interface between the solar panels and the pumps. Firstly, it matches the output power that the pump receives with the input power available from the solar panels. Secondly, a controller usually provides a low voltage protection, whereby the system is switched off, if the voltage is too low or too high for the operating voltage range of the pump.
Once the energy from the solar panels is matched with the pumps, it is used to power the motors. These motors can be either DC or AC. If AC motors are used, an inverter is used to convert the direct electricity produced from the panels. DC motors directly run on the power produced.
These motors are used to drive the pumps which can be either centrifugal or suction-force pumps which deliver water from the source to the destination.
Most solar water pumping systems come with reservoir tanks which can be used when solar power is not available. Another way to combat the intermittent nature of electricity produced from the solar systems is to have battery back-up. But this makes the system expensive and therefore is seldom used.