Solar Powered Water Pumps
Solar powered water pumps are
designed to use DC power (Direct Current) supplied by solar electric
panels. The motor in these pumps is very reliable and is designed to
continue operating even during low light conditions without stalling
or overheating so that there is a constant output or water. Operating
under these conditions means that the pump will continue to operate
under low power conditions but still deliver water at a reduced rate.
To enable them to operate under these varying conditions, most use a
positive displacement design rather than a centrifugal design which
requires higher operating speeds to work efficiently.
Solar water pumps are great
for backyard projects such as garden ponds and fountains and any other home
project where electricity is not easily available. These pumps are very
reliable, require little maintenance and last for many years.
The difference between a
positive displacement pump and a centrifugal pump
A positive displacement
pump seals water in cavities so that even when the pump speed slows during
periods of low power supply, it will continue to move the water in the
desired direction but at a reduced rate. Displacement pumps include piston,
vane and diaphragm designs. Centrifugal pumps use impellers which draw the
water in through the center of the impeller and then forces the water out of
the impeller to the pump discharge using centrifugal force. If these pumps
don’t operate above a minimum speed the water will begin flowing back
through the pump and water flow will stop.
There are two types of
solar water pumps
There are two general types
of solar powered water pumps, surface pumps and submersible pumps and both
are available with small and very large flow rates. Submersible pumps are
installed below the water surface and are used in wells, fountains and
ponds. Surface pumps are for above ground use and must be protected from the
weather. Solar powered water pumps are capable of pumping less than .5
gallons per minute (2 liters) to over 100 gallons (375 liters) per minute.
Most deep wells use submersible pumps. Surface water pumps can be used for
depths less than 30 feet (9 meters).
Ensuring there is enough
water
Many applications like a
backyard fountain and pond doesn’t require an uninterrupted, minimum supply
of water at all times because the flow of water is not really that critical,
but for farming and drinking water a minimum supply may be very important.
There are some measures that can be used to ensure that supplies are
constant and uninterrupted.
Solar trackers are often
used with these systems to control the solar panels tilt. A solar tracker is
a device that moves the solar panel keeping it at the most beneficial angle
to the sun and ensures that the water pump will be provided with the maximum
possible power all day. Another method of ensuring adequate water supply is
to use storage tanks that utilize floats to control the pumps. These floats
turn on the solar pump when the water level in the tank is low and turn them
off when the water level is high. Battery back up is even available for
these systems to ensure constant operation.
Resources:www.solar-part.blogspot.com
