Water pumping is an ideal application for solar power. Rather than using batteries, solar pump systems store water in tanks or reservoirs while the sun shines.
The proper sizing of a solar pumping system is difficult when data on borehole depths and capacities is not known. Ideally, one would like to know:
- The total dynamic head – meaning the distance from the lowest water level during pumping to the top of the tank or pipe outlet.
- The amount of water required per day – frequently clients will indicate the amount they expect per minute or hour, but this implies a continuous flow. Remember that solar water pumps need to pump all of their water during peak sunshine hours.
- The location where the pump will be installed, so that the solar insolation levels can be calculated.
In general, solar pumping is suited to small and medium pumping requirements and not for commercial irrigation or municipal water supply. For those applications, an AC pump fed from the utility grid with a countervailing grid-tied solar array might be the best solution.