Pumping Water.
At the outset of this guide it must be stated that the
definitive guide for windpump installations is :
"Windpumps, a guide for development workers"
Published by IT publications.
This guide relates to Southern Cross practical field experience.
A great proportion of the rural population in developing
countries does not have access to clean potable water. This
document outlines practical steps required in designing wind
driven water pumping schemes. It emphasizes the potential
pitfalls of water pumping windmill utilization however this
emphasis should not lead the reader to believe that windmills are
unreliable. They are easy to install and have historically proven
to be reliable up to economic lives of over 50 years. Unless
basic and simple disciplines are followed however reliability
will suffer.
Alternatives to wind driven pumping systems.
* Solar driven systems. These should be considered inapplicable
in rural developing countries due to high cost and the non
availability of skilled electronic technicians to maintain them.
It is further a little known fact that solar collector panels
have a limited life with their efficiency of converting solar
power to electricity falling off dramatically after 5 years.
* Internal combustion engine driven pumping systems.
Internal combustion engines are of limited life with small high
speed engines often having life spans of less than 1000 hours.
Larger slow speed diesel engines have longer life but once again
the technology is often not available to maintain them in the
rural developing country environment. They are particularly
vulnerable with respect to their fuel injection systems which
require sophisticated equipment to refurbish. Further the cost of
the fuel to run such engines is an obstacle to their use and the
cost of getting such fuel to remote sites makes such systems
uneconomic.
* Hand pump systems. These have found great favor in rural water
supply schemes however they are a poor solution to the problem.
Superficially the maintenance problems outlined above are
obviated due to the fact that human power is used to drive this
type of system however a simple analysis of the amount of water a
hand pump system can deliver per well (or borehole) sunk will
reveal that windmills produce water at a lesser cost than
handpumps. The confusion has arisen due to the fact that the cost
of equipping a well with a handpump is less than for a windmill
but when the cost per litre of water pumped is analyzed then the
windmill is less expensive.
Advantages of wind driven pumping systems.
* Lowest cost.
* Least maintenance (But not zero maintenance).
* Technology appropriate to less developed areas.
* Maintenance can be carried out by local populace.
The above not withstanding wind driven rural water supply systems
have a poor track record when used for potable water supply in
developing countries. This is due to much of the technology and
practical requirements of such systems having been forgotten or
not being available to modern day consulting firms responsible
for designing rural water supply systems.
This manual seeks to redress this problem. Windmills can work
satisfactorily indefinitely provided a few simple rules are
followed. It does not deal with windmill pumping performance or
windmill size selection to perform a specific pumping duty. This
is described in another Southern Cross publication.