NEW HYDROPOWER WATER WHEEL
PATENT WO 2004/048773
The water wheel was invented thousand of years ago in Mesopotamia. In the Middle Age, many mills were born in whole Europe. The water wheel run-off by under, by over, by side, etc... ensured the driving force needed for the wheel rotation.
No mill was able to use the water height pressure of natural or man-made dams.
Although hydropower is recognized as a renewable energy and without CO2 emissions, it is confronted with many ecological oppositions because of its impacts on the environment.
The integration of hydropower in green electricity products is consequently a very difficult task.
It is this report which led to the design of a new water wheel, of slow revolution speed, associated with a dam, and non destructive of aquatic ecosystems.
It is a dam paddle water wheel, for low drops (from 1 to 5m), capable of producing between 20kW and 1000kW, easy to build, and easy to implement in new sites or in replacement of old abandoned mills
It is a concept that can be considered as a soft and ecological micro-hydropower for production of green electricity.
In the XIXth century, in France, nearly 100000 water wheels were in activity, and we did not count the many wheels present all over the world.
With the industrial development, most of them were abandoned and replaced by high speed turbines which were the only ones capable of using the water height pressure of dams.
This technique was used so far with the development of hydraulic electric power
However today, although hydraulic electricity is recognized as durable, and without CO2 emission, it is sometimes confronted with an ecologic opposition due to its major drawbacks: dams destroy whole valleys, and turbines, whatever the height of the dams, even in low falls, destroy the aquatic environment. In addition, external installations needed to make the turbines work are heavy and expensive, and raise considerably the cost prices of the low drops
All kinds of paddle wheels existed: by over, by under, by side, etc... The most sophisticated was the SAGEBIEN wheel , invented in the XIXth century. Their use was then considerably reduced, no paddle wheel could use the totality of water height potential energy.
THE TURBINE FONFREDE
The old paddle wheels did not use much of the available heights. The water paddle turbine makes it possible to use the water height without calling into question the original rights (flows and canals).
The mobilization of the water height changes considerably the economic situation of these old sites, by improving them. Indeed, the energy production is maximum and several times better than that of origin, without any changes of the old data.
This opens the way to the economic rehabilitation of these sites, and the inheritance conservation. The figure shows an example of replacement, by this turbine, of an old paddle wheel, in an old site where the water height was not mobilized.
The production should be around 80kW, which allows the economic rehabilitation of the site.
It is this report which led to the design of a slow rotation speed paddle turbine, harmless for the aquatic environment, whose simple design makes it possible to propose standards (from around 20kW to 1000kW), and easy to implement, thus opening the way to an ecological alternative for the hydraulic power production, for low drops (from 1 to 5m), most of them not being used at present.
For example, 10000 drops of around 1m existed in the XIXth century in the country of the Loire.
The present turbine works with a new type of paddle water wheel which we could call dam paddle water wheel. It allows for the first time the integration of a fixed dam in the wheel and therefore the use of the totality of water height potential energy, without imposing any restraints on the natural flow.
Many alternatives of manufacture are possible.
The innovation consists in reducing the volume needed to the paddles displacement to its minimum, i.e. the envelope of the cylinder used by the passage of paddles.
This allows to have an interior volume available for the installation of fixed parts, making up a dam .
The lower part of this dam acts as a the higher wall for the paddles passage.
The paddles have an hydrodynamic shape in order to have the minimum of resistance entering the water by developing favorable hydrodynamic forces in the meaning of the wheel rotation direction.
The only hydraulic losses are the losses of the flow escape due to the manufacture precision.
The fixed parts allow to place the devices of multiplication and gear box needed to the drive of the electric generator, thus reducing the usually reserved external arrangement for this purpose.
The regulation is made, as with modern wind generators, by a disc brake which allows to stop the wheel.
When the wheel is stopped, water does not flow and the wheel acts as a closed valve. This device can so permit the use of tides energy in two directions of flow.
The axis, made of a high strength metal tree, has a very important function of maintaining and precision of the whole by the means of bearings.
Manufacture can varyÊ: the wheel diameter, its width, the paddles height and the water height are directly linked with the use parameters of the river or of the water reservoirs.
Water height can range from 0.5m to 5, or more. Manufacture of the elements, including the paddles, due to their shape, is very simple and economic, with few external expenses.
Produced energy is function of two parameters, constituted by the two different assembled elementsÊ: the rotating disc, dimensioned by the water height, and the paddles, dimensioned by the flow. It is so possible, by combining these two elements, to answer with standards (a combination of two standards) to many variations of energy production, as with the others elements of the whole turbine (multiplication, generator).
It can be useful for controlling the costs.
The design makes it possible to be freed from the heavy constraints of hydroelectric installations, with a simple and quick installation, after earthwork, of some sub-assembled hydro-generator parts, characterized precisely.
This opens a totally new equipment field with the use of lower flows and levels, and this for low equipment and exploitation costs.
DESIGN ANALYSIS AND FLOW CALCULATION
The performance analysis of the micro-hydro turbine is realized in collaboration with CREMHyG and LEGI, two Laboratories of the INP Grenoble University (France).
Global simulations taking into account the river free-surface flow are developed and used to optimized the inlet and outlet of the turbine. Design aspects as well as through-flow in the paddle wheel are also studied with commercial software.
The final objective is to ensure reliability and efficiency with an easy-to-manufacture design.
These figures illustrate a model of a dam paddle wheel which will be tested with different configurations to optimize the hydraulic design.
ENVIRONNEMENT AND ECOLOGY
This device is perfectly adapted to low-cost micro-economy development, within the framework of ecologic and durable energies.
Water circulation and flow rates stay in the framework of natural flows, paddles shapes and distance between them allows the passage of alive species without any damage, thus answering to fishermen concerns and to ecological protections.
It also let pass the majority of objects going with the flow.
Only protective grates with large mesh are necessary to block bigger objects.
This reduces all the more maintenance costs.
The arrangements remain in aesthetic optics of the traditional paddle wheels and consequent infrastructures are reduced to the minimum.