Solar water pumping provides a welcome alternative to fuel-burning generators for pumping and irrigation applications. The advantages of solar water pumping systems are many and some of the important ones are listed below.
· Solar pumping systems require no fuel. They are quiet, pollution-free and require little or no maintenance. Various facilities are available for automating the starting and stopping of water flow.
· Solar systems are expandable. A pump may be installed with the minimum number of modules. Later when economics allow, the system may be expanded to full flow capacity.
· Pumping systems are available and can be designed for small, medium and large scale water requirements. Many of the smaller sized systems cost little more than their fuel-powered equivalents.
· Solar electric powered pumping is extremely efficient. Maximum pumping power is available on sunny days when water is needed most.
· Low volume solar pumps offer the benefit of using slow water seeps in marginal wells.
· Solar pumps are very useful for lifting water from wells and pushing through pipelines that may be several kilometers long.
· When selecting a solar pumping system, the most important factors to take into account are well or borehole depth, yield of well, total vertical lift and total water requirements per day.
· A small solar system is comparable in cost to an engine powered system.
· Most larger solar systems initially cost more than fuel- powered systems but tend to be far more economic in the long run. For example, when determining the life cycle of a fuel-powered system, items such as the cost of fuel, parts, transportation and maintenance should be considered.
· A solar system minimizes future costs and cost uncertainties. The fuel is free and there is only one moving part.
With a solar pumping system you can be assured of many years of reliable water supply at near-zero operating cost.
Solar Pumping Systems
Solar pumping systems can be classed as small scale, medium scale and large scale in size. There are various technologies used such as :
1. Small scale These systems use highly efficient, low voltage, DC powered diaphragm type pumps. Typical flows are several cubic meters per day from depths of up to 60m.
2. Medium size systems These systems use multi-stage, centrifugal submersible pumps powered by state of the art high voltage brushless DC motors. Alternatively an electronic inverter is used which converts direct current into three phase variable frequency output for the motor. Typical flows are 20-30 cubic meter per day from depths of up to 100m.
3. Large Scale Systems These systems are designed for systems with heads up to 120 metres (394 feet) and with a capacity of over 185 metric tons per day. Each system is powered by an array of high powered modules thus ensuring reliability with an expected lifetime in excess of 25 years. Power from the solar array is fed into a state-of-the-art electronic inverter which converts direct current into three phase variable frequency output. Typical flows are 20-150 cubic meter per day from depths of up to 180m. Solar pumps are constructed of high quality low lead marine grade bronze and stainless steel and are designed for corrosion-free and maintenance free service even in harsh environments. They have good long term performance and reliability. The motors are submersible type and variable speed. They are pollution free, corrosion-free, self lubricating and quiet.
Solar pumping systems are usually designed to specific customer's requirements. The higher the power capacity of the system (ie. number of solar modules used), then the higher the volume of water that will be pumped.