FR2985289A1 - METHOD FOR PRODUCING ELECTRICAL ENERGY FROM TIDE MOVEMENT AND MARKER INSTALLATION - Google Patents

Abstract

The invention relates to a tidal installation comprising a unidirectional turbine and a rotating electrical machine driven by said unidirectional turbine, said unidirectional turbine being actuated by the movement of the tides. This installation further comprises: a tank (5; 50) capable of filling at rising tide and emptying at tide down; at least one pipe (10) between the interior and the exterior of the tank for filling the tidal water tank and emptying the tank at low tide; said unidirectional turbine (15) being placed in said duct for driving the rotating electrical machine (30) during filling and emptying of the tank; and means (40, 43) for closing or opening said conduit.

Description

The present invention relates first of all to a method for producing electrical energy, and more particularly to such a method using a rotary electric machine driven by a unidirectional turbine powered by a motor. The invention relates to a method for producing electric energy. the movement of the tides.

There are tidal installations built on a sea coast and including a dam closing an anfractuosity of this coast. This is for example the case of the facility built at the mouth of the Rance estuary in France, where "bulb" type turbines are installed in pipes crossing the dam. These turbines have steerable blades so that they rotate in one direction or the other in the direction of the flow that causes them, tide rising or tide down. The disadvantages of this technology are related to the fact that these turbines are complex, because of mobile elements in particular, and expensive to manufacture and maintain. Unidirectional turbines are also known, including in applications to tidal installations. A unidirectional turbine is a turbine whose direction of rotation is the same regardless of the direction of the flow that passes through it.

Thus US 4,222,700 discloses a unidirectional turbine having chevron section blades and provides for its application to a tidal installation. Other types of unidirectional turbines have been proposed, mainly in wind turbine applications where it is important that the turbines (the "propellers" in this case), here with a vertical axis, rotate in the same direction regardless of the direction of the wind. However, it is difficult in a tidal application using this type of turbine to operate under optimal nominal conditions, given that the pressure differential between the upstream and downstream turbine varies with the evolution of the turbine. tide. The invention aims to overcome the disadvantages of the prior art. More particularly, the object of the invention is to provide a method of producing electrical energy and a tidal installation making it possible to reduce the manufacturing and maintenance costs of this installation compared to known installations. The invention also aims to provide a tidal installation in which the turbine operates most of the time in optimal conditions, regardless of the phase of the tide that is considered. For this purpose, the invention firstly relates to a method of producing electrical energy using a rotary electric machine driven by a unidirectional turbine driven by the movement of the tides, this method comprising the steps consisting of: making a reservoir that can fill at rising tide and empty at tide down; providing at least one pipe between the interior and the exterior of the tank near the bottom of the tank for filling the tidal reservoir and emptying the tank at tide; placing a unidirectional turbine in said conduit to drive a rotating electrical machine during filling and emptying of the tank; and in use: closing said pipe substantially at low tide until the water level difference between the inside and the outside of the tank reaches a first predetermined (negative) value; then opening said conduit to allow filling of the tank and driving of the rotating electrical machine through the unidirectional turbine, substantially until high tide; closing said pipe substantially at high tide until the difference in water level between the inside and the outside of the tank reaches a second predetermined (positive) value; then open said pipe to allow the emptying of the tank and the driving of the rotating electrical machine through the unidirectional turbine, substantially until low tide. It is thus possible to use a fixed blade turbine, in particular such a turbine whose blades are chevron section. This results in a reduction in turbine manufacturing and maintenance costs.

By temporarily closing the pipe during the low tide or low tide phases, and consequently stopping the turbine and the rotating electrical machine, it is avoided to rotate this set at very low speeds and with very poor yields.

In a first particular mode of implementation of the method of the invention, said tank is made by closing by a dam an anfractuosity of a sea coast, such as a loop or a river estuary, and said pipe is formed in the thickness of said dam. The dam can for example be built between the ends of a loop or across the mouth of an estuary. This construction is done by providing one or more pipes through the dam dam, in which is placed the unidirectional turbine. At rising tide, the portion of the pipe located between the outer end of the pipe (sea side) and the turbine forms the water intake channel, and the portion of the pipe located between the turbine and the end The inside of the pipe (side of the crevice of the coast) forms the water discharge channel. The situation is reversed at tide. In a second particular embodiment of the method of the invention, said tank is made by constructing a basin having a bottom and walls, the bottom being substantially at low tide and the walls rising substantially at high tide, and said pipe is formed in the bottom or wall of the basin.

Also in a particular embodiment, the difference in water level between the inside and outside of the tank is kept substantially constant at said first (respectively second) predetermined value during filling (respectively emptying) of the tank, with the exception of the end of the filling phase (respectively the emptying phase) where the levels tend to equalize. Thus, the characteristics of the turbine can be selected so as to be optimal for the upstream / downstream pressure differential corresponding to the difference in water level. The turbine therefore runs at its nominal speed during most of the tidal cycle. The invention also relates to a tidal installation comprising a unidirectional turbine and a rotating electrical machine driven by said unidirectional turbine, said unidirectional turbine being actuated by the movement of the tides, this installation further comprising: a reservoir capable of filling with tide rising and emptying at tide down; at least one pipe between the interior and the exterior of the tank for filling the tide tank and draining the tank at tide; said unidirectional turbine being placed in said conduit for driving the rotating electrical machine during filling and emptying of the tank; and means for closing or opening said conduit. In a first particular embodiment of the tidal installation of the invention, said reservoir is formed of a natural crevice of a sea coast, such as a cove or the estuary of a river, and of a dam closing said anfractuosity, said pipe being formed in the thickness of said dam. More particularly, said pipe may have in axial section a shape substantially S, opening substantially horizontally inside and outside the tank, said unidirectional turbine being disposed in the middle part of the pipe with its substantially vertical axis. In a second particular embodiment of the tidal installation of the invention, said tank is formed of a basin having a bottom and walls, said pipe being formed in the bottom or a wall of the basin. More particularly, said tank may have a funnel shape, said unidirectional turbine being placed at the bottom of said funnel with its substantially vertical axis.

Also in a particular embodiment of the tidal installation of the invention, the means for closing or opening said pipe may comprise a valve and means for controlling and actuating the opening and closing of said valve. Two embodiments of the invention will now be described, by way of nonlimiting example, with reference to the appended diagrammatic drawings in which: FIGS. 1 to 7 schematically illustrate the successive phases of a process according to the invention; FIG. 8 is a schematic perspective view of a turbine 20 that can be used in the implementation of the method of FIGS. 1 to 7, FIG. 9 is a sectional ground plane of the dam of an installation. According to the invention, FIG. 10 is an enlarged view of the detail X of FIG. 9, and FIG. 11 schematically illustrates another embodiment of the invention in section along a vertical plane. . With reference to FIGS. 1 to 7, there is shown a dam 1 consisting of a vertical wall 2, placed on a raft 3 and supported on either side by buttresses 4. The dam 1 is for example built between the two banks of an estuary (not shown). The dam 1 delimits, with the parts of the banks of the estuary located upstream of the dam, a reservoir of reservoir 5. Downstream of the dam is thus the sea whose level oscillates according to the tides between a level of high tide 6 and a low tide level 7. Tidal coefficients will not be taken into account here, without affecting the description that follows.

Referring now more particularly to FIGS. 9 and 10, the interior of the tank 5 will be referred to hereafter as the upstream side of the dam 1, and its outside as the sea side. During the construction of the dam 1, pipes 10 are provided. in the wall 2 of the dam 1 between the buttresses 4, 10 longitudinally along the length of the dam. These pipes 10 pass through the wall 2 to connect the inside and the outside of the tank 5. A pipe 10 presents in axial section a shape 11 substantially S (Figure 1), and opens at its ends both inside. and outside the tank 5 with its horizontal axis. An inclination of the axis of the pipe 10 with the horizontal at its outlets is nonetheless conceivable for the purpose of optimizing the flow of water. In its middle part, the axis of the pipe 10 is vertical, and a unidirectional turbine 15 is installed at this location on not shown supports, with its vertical axis. The unidirectional turbine 15 is here composed of a rotor 16 and two distributors 17 (only one shown in Figure 8), arranged on either side of the rotor. It should be noted that, for the sake of simplification, the distributors of the turbine 15 have not been shown in FIGS. 1 to 7, the turbine having been illustrated in these figures by the schematic representation of the rotor alone. The rotor of the turbine 15 is composed of a hub 20 (FIG. 8) on which vanes 21 with a chevron section are fixed. Each distributor 17 has vanes 22 oriented to direct the liquid flow in the proper direction to actuate the vanes 21 optimally regardless of the flow direction of the water. Such unidirectional turbines, rotating in the same direction irrespective of the direction of the flow which causes it, are known in the state of the art, and this will not be described in more detail. An alternator 30 is coupled to the axis 31 of the turbine 15 (Figure 9) so as to provide electricity when the turbine 15 is driven by the water flow. The system may be reversible, so that the turbine 15 operates as a pump when driven by the machine 30 powered by an electric motor. The installation according to the invention further comprises a valve intended to close or open the pipe 10. For a better understanding of the drawings, this valve is represented in the figures both in its closed position with the reference 40 and in its open position. with the reference 40 '. The valve 40 is constituted by a generally flat panel pivotally mounted about a horizontal axis 41 on a yoke 42 (Figure 10). The yoke 42 is installed in any suitable manner on the outside of the wall 2 of the dam 1. Thus, the valve 40 can here open towards the outside of the tank 5. Means 43 for controlling and actuating the opening and closing of the valve 40 are provided to ensure the movements of the valve 40. The control can be manual, or subject to forecasts ephemeris tides, or slaved to pressure or other measures. FIG. 11 describes another embodiment of a tidal installation according to the invention. The elements corresponding to those of the previously described figures have received the same reference. It should be noted that for the sake of simplification, the dispensers of the turbine 15 have not been shown in FIG. 11, the turbine 15 having been figuratively illustrated in this figure. Here, the reservoir 5 is formed of a basin delimited by a masonry construction 50 preferably made near the shore of a sea or ocean of course with tides, and installed on the floor 51 by non-existent supports. represented, at sea or on land. The basin has a bottom 52 and side walls 53.

This basin has, in the embodiment shown, a funnel shape. The upper edge 54 of the side walls 53 of the masonry 50 is here slightly higher than the level 6 of the high tide and its bottom 52 is substantially at the level 7 of the low tide.

The bottom of the masonry 50 is open to form the pipe 11 in which the turbine 15 as described above with its distributors (not shown in Figure 11) is disposed with its vertical axis, and the valve 40 (40 ' ). The unidirectional turbine 15 is as previously coupled to an alternator 30 via a shaft 31. The portion of the pipe 11 outside the basin is connected to the sea. Referring now to FIGS. 1 to 7 to describe the control and the operation of the tidal installation that has just been described with reference to these figures. It will be understood by those skilled in the art that the control and operation of the tidal system of Figure 11 are equivalent. Figures 1 to 4 illustrate the filling of the tank 5 and Figures 5 to 7 illustrate its emptying. Figure 1 shows the installation at low tide and at the beginning of rising tide (phase I). The valve 40 is closed. The level of the tank 5 is that of the low tide 7 (tide of 0 meters). The tide is rising. Phase I begins at to. This phase extends until the tide reaches a level 100 such that its difference in level with that of the reservoir, that is to say between the inside and the outside of the tank 5, reaches the first level. predetermined value h1, for example 1.70 meters, which phase may for example last 1 hour (end of phase I to + 1 hour). No flow circulates during this phase in the pipe 11 and the moving element 15, 30 remains fixed. The first predetermined value h1 is then negative because the level inside the reservoir is lower than that of the outside. The valve 40 is then open (position 40 ') and the installation enters phase II of operation (rated speed). FIG. 2 represents this operating phase II, for example at + 1.5 hours, with a tidal level 101 equal, for example, to 2.50 meters. During this phase, a flow flows in line 11 from the outside inside the tank according to the arrows F 1 and the turbine drives the alternator. The characteristics of the installation, in particular the flow rate of the turbine or turbines, were determined by the person skilled in the art, taking into account the possible supply of water by the river feeding the estuary, so that the difference in level between the inside and the outside of the tank 5 remains constant, equal to h1.

Figure 3 shows the installation in the same phase II as that of Figure 2, with a tidal level 105 equal for example to 5 meters to + 3 hours. The rated speed remains with a level difference between the inside and the outside of the tank 5 equal to h1 and the flow continues according to the arrows Fl.

This nominal speed ceases (entered in phase III when the difference in level h between the inside and the outside of the tank 5 becomes lower than h1 because the tide gradually becomes high and the inner and outer levels The valve still remains open (position 40 ') to allow the levels to equalize and the flow continues according to the arrows F 1 with a decreasing flow rate The valve is closed (position 40) to high tide (to + 6 hours) while the difference in level between the inside and the outside of the tank 5 becomes zero.

The installation then enters the tide. The different phases reproduce substantially identically by inverting the inner and outer levels. The second predetermined value h2 is now positive because the level inside the reservoir is higher than that of the outside. It is not necessarily equal in absolute value to h1 to take into account any circumstances specific to the installation. Figure 5 is the tide equivalent of Figure 1, Figure 6 is the equivalent of Figure 2, and Figure 7 is the equivalent of Figure 4. Arrows F2 indicate flows in the opposite direction of Arrows Fl. The phases of dead time, that is to say phase I at rising tide, for example between to and to + 1 hour as indicated above as an example, and the corresponding phase reverse tide downstream, during which no flow circulates in the pipe 11 and therefore passes through the turbine 15, can be offset by a power generation provided by one or more additional facilities as described below.

An additional installation (not shown) comprises for example one or more tanks of compressed gas, in particular air, which are filled by one or more air compressors. The air compressor or compressors are rotated by means of one or more electric motors whose power supply is advantageously provided by the alternator 30 coupled to the turbine 15, during phase II at rising tide, and the phase corresponding inverse at tide. It is conceivable that, for example, 20% of the generation of electricity by the alternator 30 during this phase II and corresponding inverse is allocated to the production of compressed air as relay energy. This compressed air contained in the compressed air reservoir (s) will supply one or more compressed air engines during phase I and the corresponding reverse phase, to rotate one or more other alternators connected to the compressed air engines which are powered by the reservoirs, in the absence of flow through the turbine 15, and thus ensure continuity of electricity production for the electricity network supplied by the tidal installation described.

Claims (12)

REVENDICATIONS1. A method of producing electrical energy using a rotating electric machine driven by a unidirectional turbine driven by the movement of the tides, characterized in that it comprises the steps of: - producing a reservoir (5; ) likely to fill at high tide and empty at tide; - close to the bottom of the tank, at least one pipe (10) between the inside and the outside of the tank for filling the tank tide and emptying the tank tide down; placing a unidirectional turbine (15) in said conduit to drive a rotating electrical machine (30) during the filling and emptying of the tank; and in use - closing said pipe substantially at low tide until the difference in water level between the inside and the outside of the tank reaches a first predetermined value (h1) (negative); - Then open said pipe to allow the filling of the tank and the driving of the rotating electrical machine through the unidirectional turbine, substantially until high tide; - closing said pipe substantially at high tide until the difference in water level between the inside and outside of the tank reaches a second predetermined value (h2) (positive); - Then open said pipe to allow the emptying of the tank and the driving of the rotating electrical machine through the unidirectional turbine, substantially until low tide. 2. Method according to claim 1, wherein said reservoir is made by closing by a dam (1) an anfractuosity (5) of a sea coast, such as a loop or river estuary, and said pipe is formed in the thickness of said dam. 3. Method according to claim 1, wherein said tank is made by constructing a basin (50) having a bottom (52) and walls (53), the bottom being substantially at low tide and the walls rising. substantially at high tide, and said pipe is formed in the bottom or wall of the basin. 4. Method according to one of the preceding claims, wherein the difference in water level between the inside and the outside of the tank is kept substantially constant at said first (respectively second) predetermined value during filling (respectively draining). ) of the tank, with the exception of the end of the filling phase (respectively the emptying phase) where the levels tend to equalize. Tidal installation comprising a unidirectional turbine and a rotating electrical machine driven by said unidirectional turbine, said unidirectional turbine being actuated by the movement of the tides, characterized in that it further comprises: a reservoir (5; fill up at high tide and empty at tide; at least one pipe (10) between the interior and the exterior of the tank for filling the tidal water tank and emptying the tank at low tide; said unidirectional turbine (15) being placed in said pipe for driving the rotating electrical machine (30) when filling and emptying the tank; and means (40, 43) for closing or opening said conduit. 5 Tidal installation according to claim 5, wherein said reservoir is formed of a natural crevice (5) of a sea coast, such as a cove or the estuary of a river, and a dam (1). ) closing said anfractuosity, said pipe being formed in the thickness of said dam. 7. tidal installation according to claim 6, wherein said pipe has in axial section a shape (11) substantially S, opening substantially horizontally inside and outside the tank 15, said unidirectional turbine being arranged in the part median of the pipe with its axis substantially vertical. A tidal installation according to claim 5, wherein said tank is formed of a basin (50) having a bottom and walls, said pipe being formed in the bottom or wall of the basin. 9. tidal installation according to claim 8, wherein said tank has a funnel-shaped, said unidirectional turbine being placed at the bottom of said funnel with its axis substantially vertical. 10. Tidal installation according to one of claims 5 to 9, wherein the means for closing or opening said conduit comprises a valve (40) and means (43) for controlling and actuating the opening and closing of said valve. Tidal installation according to one of claims 5 to 10, wherein said unidirectional turbine is a fixed blade turbine (21). 12. tidal installation according to one of claims 5 to 11, wherein said unidirectional turbine is a turbine whose blades are chevron section.