design combines simple
components for the required task. It is based on readily available parts making it easy to
prototype. Due to its
modular nature, each component can be optimized separately. By
leveraging open source hardware design
parts can be developed by a group of volunteers which reduces the price significantly.
The system will be distributed as a kit by an open source social business, thus allowing local entrepreneurs to participate in the value chain as much as possible while keeping the price at a minimum. Profits from kit distribution will be re-invested into the project.
This photovoltaik system has the advantage of light weight and mobility. It has four wheels for easy transport and flexible light-weight solar panels which can be folded on top of each other like the wings of a bee during transport (bee-design). Both wings together have a maximum peak power of about 300 Wp (Example for such a panel: http://www.solarion.net).
The water has to be recovered from a depth of only 5 m. Therefore, the efficient brushless DC 12 V pump is designed to maximize flow for this depth. Rather than using one big pump (which requires >=24 V system voltage), we use four small pumps each delivering about 25 l / min while consuming 60 W of electric power. This delivers 6000 l / hour.The pumps can be directly powered from the solar panels.
The system can be enhanced with electric energy storage. Stored energy allows some bonus functions in the evening. It can power lights, music and radios, computers, mobile phones, electric tools and other small appliances. The rechargeable batteries can
be charged by the sun
(we have some excess power from the panels) or a
diesel electricity generator or even
from the grid in case of bad
sun conditions. They can be fast-charged
which allows a central generator to provide energy to several such
systems. One Wh of LiFePo4 energy
storage capacity costs about
To run the
pumps for three hours requires 750 Wh of storage capacity (12h*60W)
which costs around
375 $. In principle, the
battery could also be used to power the pumps during the night to double
the flow rate in certain weather
A water distribution system will be required to increase efficiency because of the reduced flow rates compared to diesel pumps. Several sprinkler systems can be connected to the system which can be placed on the field and moved around during the day.
- everything available and proven technologies
- open source social business approach can deliver kits for local assembly and provide an internet community for support
- flexible solar cells don't break during transport
- several pumps in parallel reduce the risks of breakdowns
- Optional LiFePo4 batteries allow additional functions and can be fast-charged by a generator to power the pumps if necessary