The present invention relates to a device for producing mechanical energy by means of a divergent chimney, telescopic and auto sustained, made from composite materials. The tilted walls of the chimney are shaped to be widened towards the top, and exert on the internal airflow, a thrust well above the buoyancy, leading the turbine to speeds near to 100 m/s. The low pressure of the air in the chimney, allows the self-lifting of the whole device.
The principle of generating electricity from the warm air near the ground, channeled into a chimney and ejected at an altitude is known and in particular was the subject of research in Spain and Australia (“solar-tower program”). A 195 m height experimental tower was set up in Manzanares, south of Madrid, and functioned by producing an average power of 50 kW between 1986 and 1989 with a reliability rate of 95%.
The process used consists in making the air pass in a prestressed concrete chimney of straight cross-section, and collecting, by means of a turbine coupled to an alternator, part of the energy of the internal airflow perpetually set in motion by the buoyancy, resulting in the difference between the density of the air located outside and that of the warmer and lighter air channeled inside.
The Australian project was followed a few years later by a 1000 m high tower which had its share of technical difficulties, in particular with respect to the constraints of construction in terms of great height and the seismic requirements as well as a very significant cost of about 500 to 750 million dollars US.
Other similar inventions have since originated all over the world, but have implemented only the buoyancy aspect and presented the major disadvantage of requiring an expensive structure to get the necessary and sufficient height for this operation, which can be estimated from 200 to over 1000 meters.
The advantages provided by this invention, compared to the known techniques to recover the buoyancy being exerted on the warm air passing through a chimney are as follows:
1) The thrust exerted by the tilted walls on the hot indoor airflow, is more than 1000 times higher than the buoyancy on the same airflow moving upwards in the chimney. This results in air speeds of more than 100 m/s at the turbine level installed at the pass, before the input of the chimney, which very much exceeded the result of widely conducted earlier experiments using only buoyancy, which recorded speeds of about 15 m/s. The energetic efficiency is thus increased tenfold.
2) The chimney is auto-sustained in the air and does not require costly structure of concrete or other materials to remain deployed, and can be easily located anywhere, including above the sea (with condition of being sheltered from sea swells) or in seismic zone. This advantage results from the permanent depression prevailing inside the chimney at any level, from the pass located at the turbine to the exit of the air at altitude. As a result of this pressure difference, which the outdoor air exerts on the tilted walls of the chimney, a thrust upwards strong enough to compensate the thrust downwards of the indoor airflow moving upwards, is added to the weight of the structure of the chimney. The pressure difference generates a thrust upwards stronger than the weight of the chimney added to the thrust downwards of the air moving up against the walls of the chimney.
3) The lower air pressure, which prevails inside the chimney for any altitude, is the result of the energy taking on the airflow when it goes through the turbine at the pass and of the acceleration of the air channeled into the chimney through the intake duct having a convergent shape.
4) The chimney is telescopic, allowing its ground assembly, without costly work of great height, as well as its deployment from the ground and its folding, from the ground particularly for maintenance or during bad weather.
The present invention comprises an extremely lightweight chimney, mainly made up of composite materials (fiberglass, carbon or other materials, resistant to sunning), which can float in the air and deliver a useful output of a few hundred of mega-watts (see
The use of these materials confers a great lightness and a sufficient rigidity to the chimney, allowing it to preserve its shape notwithstanding the effects of its own weight and the involved aerodynamic loads.
A divergent section whose angle varies between 1 and 5 degrees compared to its central axis,
A height (6) of several hundred meters and a diameter (13) of a few tens of meters.
Telescopic elements of the chimney are subjected to the pressure of the external atmosphere, higher than that of the internal air. As shown in
As shown in
Under the effect of aerodynamic forces, including the upward thrust exerted on the deflector output (9), the telescopic elements of the chimney are kept under vertical tension. The vertical tension is sustained through the peripheral walls of the chimney. As shown in
The intake duct (1), as shown in
The upper surface (11) is fixed at lower surface by means of six vertical walls laid out and distributed radially. The six vertical walls have a double function to fix together the lower and the higher surfaces, and to channel the air towards the pass of the chimney in reducing as much as possible the loss of load.
Mechanical energy is collected by means of a turbine (2). The turbine is horizontally laid out at the level of the pass separating the intake duct (1) from the body of the chimney (3). This arrangement collects energy where the air velocity is the highest, which maximizes output.
In reference to the figures, the numbers correspond to components as follows:
When the movement of the interior chimney air has reached steady state, the acceleration of the air in the intake duct of convergent shape, and its passage through the turbine creates low pressure in the chimney compared to exterior air. This pressure difference between the air pressure of the exterior and the interior air exerts on the entire perimeters of the inclined walls of the chimney, a thrust upwards which allows the lift of the chimney owing to the fact that it consists of light materials, made stiff by composite materials.
Deployment
The process of lifting of the chimney is as follows: all the elements are settled on the ground, by nesting one element inside the other (cf.
The last element surmounting the deflector is filled with heated air which cannot escape for, at the starting, the sliding shutters are maintained in high position (
Because of difference in density between the outdoor air and the hot air within the last element, the chimney is subjected to a buoyant force, like a hot air balloon, and undergoes an upward movement. When the upper element has risen sufficiently, it fixes itself along the higher edge of the following lower element (
When all the elements have been raised in the air, the sliding shutters (10) of the last telescopic element, under the exit deflector (9) are completely opened in order to let the air escape. The hot air (8) contained within the chimney escapes through the top, and thus permits transit of the warm air (7) from the ground through the chimney.
Steady State
Air located close to the ground is channeled in the intake duct (1) divided into six equal radial spans to reduce the loss of load in the entry, and is guided in radial movement towards an upward vertical movement.
The air actuates a turbine (2) horizontally laid out at the level of the pass of the chimney at the exit of the intake duct.
At the exit of the chimney, the air (8) is channeled in the deflector shaped as a half-torus opened on its lower face, divided by six equal spans. The division in six spans directs the air to the exit with a minimum loss of load. The shape of the deflector in a down-opened half-torus (9) drives the air downwards and thus provides thrust necessary to lock the entire structure together.
The outgoing airflow is adjusted according to the directions of each of the six spans by means of the sliding shutters (10) actuated with an electric motor (23). Thus, the airflow direction at exit is adjustable on request to create a horizontal thrust at the top of the chimney necessary to compensate for wind forces exerted on the chimney's entire height. The outgoing airflow direction is controlled from the ground by a computer (24).
This device must be set up in a warm area to avoid the risk of deposit of ice, Ice deposits would increase the weight of the structure jeopardizing its aerodynamic stability.
The intake air speed and the power retained by the turbine are controlled so as to preserve a positive temperature (in Celsius degrees) to avoid any risk of deposit of ice inside the structure.
Folding Up
For maintenance operation or during very bad weather, the telescopic elements (4) are brought back to the ground, by means of the cable (14) of composite material, which is positioned along the axis of the chimney. The cable, connected to each fixed wheel (15) by a device like thrust collar against diaphragm, exerts a traction only on the telescopic element nearest to the ground. The higher elements up to the deflector output are maintained in traction throughout the descent by their peripheral walls.
When each element touches the ground, a device opens the diaphragm (22), which releases the thrust collar and allows the cable to continue its descent. (See
This maintains the structure in traction throughout its descent by the fact that the air is guided downwards at the level of the deflector output, retaining control of the process of folding up at any point in time.
During this phase, the speed of the inlet air in the chimney is maintained by the turbine, which provides the necessary energy to the airflow, so as to ensure the safety of the folding-up operation.
The present invention produces electricity from a completely renewable energy source, without producing any industrial waste or any greenhouse effect.
It is particularly adapted to the warm areas of the world, away from the risk of freezing. It can function without interruption with a minimum of human intervention related to its monitoring and the delicate operations of deployment and folding up.
It can be established in any place with just the infrastructure necessary for the setting up of the intake duct, which needs an area on the ground ranging between 45 and 100 meters in radius. It can be established on the sea if it is sheltered from sea swells. In this case it can be coupled with a hydrogen plant for hydrolysis of seawater.
The present invention is equipped for example with a chimney of 500 m height and 15 m radius at the pass, and can produce between 200 and 400 MW on request. It is thus possible with this means to adjust the level of production to that of consumption, complementing large-scale electricity production.
Number | Date | Country | Kind |
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06 00717 | Jul 2006 | FR | national |
06 06462 | Jul 2006 | FR | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/FR2007/000922 | 6/5/2007 | WO | 00 | 6/8/2008 |
Publishing Document | Publishing Date | Country | Kind |
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WO2008/009785 | 1/24/2008 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
1612838 | Schutz | Jan 1927 | A |
4036916 | Agsten | Jul 1977 | A |
4070131 | Yen | Jan 1978 | A |
4421452 | Rougemont | Dec 1983 | A |
4508973 | Payne | Apr 1985 | A |
4963761 | Wight | Oct 1990 | A |
5982046 | Minh | Nov 1999 | A |
6590300 | Preito Santiago | Jul 2003 | B1 |
7400057 | Sureshan | Jul 2008 | B2 |
Number | Date | Country |
---|---|---|
854948 | Sep 1977 | BE |
2466189 | Nov 2005 | CA |
2307982 | Dec 1976 | FR |
WO 2004036039 | Apr 2004 | WO |
WO2006022590 | Mar 2006 | WO |
Number | Date | Country | |
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20080292456 A1 | Nov 2008 | US |