Solar Water Pumping
If you need to supply water beyond the reach of the power lines, then solar power can solve the problem. Photovoltaic powered pumps provide a welcome alternative to fuel burning engines, windmills, and hand pumps. Thousands of solar powered pumps are working throughout the world. These produce best during sunny weather when the need for water is greatest.
Solar water pumps are specially designed to utilize DC electric power from photovoltaic panels. They must work during low light conditions at reduced power without stalling or overheating. Low volume pumps use positive displacement (volumetric) mechanisms which seal water in cavities and force it upward. Lift capacity is maintained even while pumping slowly. These mechanisms include diaphragm, vane, and piston pumps. These differ from a conventional centrifugal pump that needs to spin fast to work efficiently. Centrifugal pumps are used where higher volumes are required.
Compared with windmills, solar pumps are less expensive, and much easier to install and maintain. They provide a more consistent supply of water. They can be installed in valleys and wooded areas where wind exposure is poor. A PV array may be placed some distance away from the pump itself, even several hundred metres (100 m) away.
