low flow applications

Solar Water Pumping System has a long history; so many methods have been developed to pump water with a minimum of attempt. These have utilized a variety of power sources, namely human energy, animal power, hydro power, wind, solar and fossil fuels for small generators. 1. Run independently from the house system. 2. Work without batteries, since batteries, convenient though they may be for storing power, are expensive, require maintenance, and have a short lifespan compared to the solar panels that keep them charged. Most importantly, batteries introduce an extra degree of inefficiency into a system. 3. Operate on DC power, and would thus not require an expensive inverter and an additional loss in efficiency. This type is probably the most common type of solar pump used for village water supply. The advantages of this configuration are that it is easy to install, often with lay-flat flexible pipe work and the motor pump set is submerged away from potential damage.

A Solar Water Pumping System for village water supply, a invariable water demand throughout the year occurs, although there is need to store water for periods of low lagging (low solar radiation). Typically in Rajasthan in India the storage would be 3-5 days of water demand. In environments where rainy seasons occur, rainwater harvesting can offset the reduced output of the solar pump during this period. The majority of the 6000 or more solar pumping systems installed to cultivate for villager. This configuration was widely installed with turbine pumps in Rajasthan in India during the 1970s. It gives easy access to the motor for brush changing and other maintenance. The low efficiency from power losses in the shaft bearings and the high cost of installation has been disadvantages. In general this configuration is largely being replaced by the submersible motor and pump set.

The technology:Water, Because it's so often hard to come by without the application of a considerable amount of electric power, those of us living off the power grid seem to have a preoccupation with it. Generally, we either carry water home from town in a big tank lashed into the bed of a one-ton pickup, use a fossil-fuel-guzzling generator to run a power-hungry AC (alternating current) well pump, or we simply beef up our solar arrays and improve our inverters to handle the load imposed by the ravenous well pump. The reciprocating positive displacement pump (often known as the jack or nodding donkey) is very suitable for high head, low flow applications.

Of the three, I prefer the option that doesn't require me to fire up an internal combustion engine--either the one in my temperamental '72 Chevy 4 x 4, or the one that runs my quiet and compliant 6.5 kW Honda generator. Pumping water from a deep (540-foot, in our case) well with no other input than sunlight and wind is quiet, automatic, and esthetically pleasing. Solar pumping technology continues to improve. In the early 1980s the typical solar energy to hydraulic (pumped water) energy efficiency was around 2% with the photovoltaic array being 6-8% efficient and the motor pump set typically 25% efficient. Today, an efficient solar pump has an average daily solar energy to hydraulic efficiency of more than 4%. Photovoltaic modules of the monocrystalline type now have efficiencies in excess of 12% and more efficient motor and pump sets are available. A good sub-system (that is the motor, pump and any power conditioning) should have an average daily energy throughput efficiency of 30-40%.