Offshore buoyancy-assisted gravity energy storage method and device

Abstract

The invention discloses an offshore buoyancy-assisted gravity energy storage method and device which comprises a movable or fixed ocean platform, a pulley block and a motor unit are installed on the ocean platform, a first transmission cable linked with the motor unit is arranged on the pulley block in a penetrating mode, and a speed regulation floating body and a speed reduction buffering device are fixed to the two ends of the first transmission cable respectively. A weight is mounted at the lower end of the speed-regulating floating body. In an initial state, the heavy object sinks on a seabed or droops in seawater and is located at a low position, during energy storage, the electric drive motor unit lifts the heavy object to a high position and fixes the heavy object, electric energy is converted into potential energy and stored, and during energy release, after the heavy object is released and the speed regulation floating body makes contact with the seawater, the sinking speed of the heavy object is adjusted until the heavy object sinks at a constant speed. And finally, the deceleration buffer device controls the heavy object to decelerate until the heavy object stops, the heavy object returns to the low position, in the sinking process of the heavy object, the first transmission cable drives the motor unit to generate electricity, potential energy is converted into electric energy, and electric energy storage of buoyancy assisting gravity is achieved through energy storage and energy release circulation.

Description

Technical Field

[0001] The invention relates to the technical field of energy storage, in particular to a method and a device for buoyancy-assisted gravity energy storage for use at sea. Background Art

[0002] Mechanical energy storage (including solid gravity potential energy storage and pumped storage) technology is to transport solid heavy objects or water to high places to store potential energy, release the heavy objects or water when power generation is needed, convert them into mechanical energy through corresponding transmission devices, and finally convert them into electrical energy through generators.

[0003] Traditional mechanical energy storage projects rely on large height differences, and the best project location is to build the project according to the existing terrain environment (such as solid gravity potential energy storage projects are built in cliffs, deep pits, etc., and pumped storage uses high-altitude reservoirs to store and release water). However, these conditions are relatively special and cannot be used as a universal solution for large-scale energy storage. Therefore, the existing conventional method is to artificially build high platforms or dig deep wells, but no matter which method is used, it has a large amount of engineering. In addition, the use of solid heavy objects for energy storage may occupy valuable land resources or interfere with surrounding production and life.

[0004] Technically, during the discharge process of pumped storage projects, regulating valves, speed regulators, etc. can be used to accurately control the flow of water, thereby controlling the stability of power generation. However, for solid gravitational potential energy storage projects, solid heavy objects follow the law of free fall when falling and are in accelerated motion, while power generation requires uniform motion. Therefore, during the power generation process, a reverse force needs to be applied to slow down the acceleration and make it uniform to maintain the stability of power generation. Although the speed can be controlled by methods similar to the balancing iron block in the elevator shaft, this will also consume some electrical energy and increase the complexity of the control project and equipment. Summary of the invention

[0005] In order to overcome the deficiencies of the prior art, the present invention provides a method and device for buoyancy-assisted gravity energy storage for offshore use.

[0006] The technical solution adopted by the present invention to solve its technical problem is: A method for buoyancy-assisted gravity energy storage for use at sea, the method comprising: establishing a mobile or fixed marine platform at sea, installing a pulley block and a motor unit on the marine platform, passing a first transmission cable linked to the motor unit through the pulley block, a speed regulating float being fixed at one end of the first transmission cable, a deceleration buffer device being fixed at the other end, and a weight being installed at the lower end of the speed regulating float. In the initial state, the weight sinks on the seabed or hangs in the sea water and is located at a low point. When storing energy, the electric power drives the motor unit to lift the weight to a high point and fix it, converting the electrical energy into potential energy and storing it. When releasing energy, the weight is released and sinks under the action of gravity. After the speed regulating float contacts the sea water, the sinking speed of the weight is adjusted by the speed regulating float until it sinks at a uniform speed. Finally, the deceleration buffer device controls the weight to buffer and decelerate until it stops, so that the weight returns to a low point. During the sinking process of the weight, the first transmission cable drives the motor unit to generate electricity, converting the potential energy into electrical energy, and realizing buoyancy-assisted gravity electrical energy storage through energy storage and release cycles.

[0007] A buoyancy-assisted gravity energy storage device for use at sea, comprising a mobile or fixed marine platform established at sea, a pulley block and a motor unit installed on the marine platform, a first transmission cable linked to the motor unit is passed through the pulley block, a speed regulating float is fixed at one end of the first transmission cable, a deceleration buffer device is fixed at the other end, and a weight is installed at the lower end of the speed regulating float.

[0008] The pulley group includes a first pulley, a second pulley, a third pulley, and a fourth pulley. The third pulley and the fourth pulley have the same installation height, and the second pulley has the lowest installation height. The first transmission cable passes through the first pulley, the second pulley, the third pulley, and the fourth pulley in sequence, and the second pulley is connected to the motor unit in terms of transmission.

[0009] The motor unit comprises a generator motor unit and a drive motor unit, wherein the generator motor unit and the drive motor unit are connected to a first gear through a clutch transmission gear box, and the first gear rotates synchronously with the second pulley.

[0010] A weight launching area is provided on the offshore platform corresponding to the weight, a movable load-bearing plate for placing the weight is installed on the weight launching area, a groove similar to the lower end of the weight is provided in the middle of the load-bearing plate, the lower end of the weight is placed on the groove, and an elastic buffer pad is placed between the weight and the groove.

[0011] The deceleration buffer device includes a slide rail seat and a buffer float installed on the marine platform. A slider pushed downward by a spring is installed in the slide rail seat. A through hole is provided at the center of the slider. A clamping block is installed after the first transmission cable passes through the through hole. The size of the clamping block is larger than the size of the through hole. The buffer float is connected to the slider through a first reversing wheel and a second transmission cable.

[0012] The deceleration buffer device includes a second reversing wheel group, a third reversing wheel group, a slide rail seat installed on the marine platform, and a buffer float. A slider pushed downward by a spring is installed in the slide rail seat, and a through hole is provided at the center of the slider. A clamping block is installed after the first transmission cable passes through the through hole, and the size of the clamping block is larger than the size of the through hole. A first counterweight block is installed between the second reversing wheel group and the third reversing wheel group. A third transmission cable is passed through the second reversing wheel group to connect the first counterweight block with the slider. A fourth transmission cable is passed through the third reversing wheel group to connect the first counterweight block with the buffer float. A second counterweight block with the same gravity as the first counterweight block is installed on the buffer float.

[0013] A spring washer is fixed to the end of the spring.

[0014] The deceleration buffer device comprises a winch bracket, on which a winch drum driven by a take-up motor is mounted, and the first transmission cable is wound around the winch drum.

[0015] The beneficial effects of the present invention are: The present invention is built on an offshore platform, which has little impact on the inland environment, will not occupy farmland or land, and will not affect the surrounding transportation and production and living environment. The vast sea area provides sufficient space and there is no need to worry about occupancy issues.

[0016] There is no need to build high towers or dig deep wells. The characteristics of the ocean's depth can easily solve the space problem of rising and lowering heavy objects, making it suitable for large-scale engineering construction.

[0017] By combining the buoyancy of a fixed speed-regulating float with the flow resistance of the weight that increases with the speed and the sinking of the speed-regulating float, and balancing the gravity of the sinking weight, the weight can achieve uniform motion in the shortest time, which is more suitable for power generation and can also more effectively utilize buoyancy potential energy for energy conversion.

[0018] The deceleration buffer device is used to gradually decelerate the heavy object, thereby improving the stability and safety of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0020] Figure 1It is one of the structural diagrams of Example 1 (energy storage state); Figure 2 This is the second structural diagram of Example 1; Figure 3 It is one of the structural diagrams of Example 2 (energy storage state); Figure 4 This is the second structural diagram of Example 2; Figure 5 It is one of the structural diagrams of Example 3 (energy storage state); Figure 6 This is the second structural diagram of Embodiment 3 (energy storage state); Figure 7 It is a schematic diagram of the structure of a clutch transmission gearbox; Figure 8 yes Figure 1 A magnified view of middle; Fig. 9 It is a structural diagram of the load-bearing plate; Fig.10 This is the effect of conventional speed regulating float on speed change; Fig.11 It is a curve chart of speed change before and after the addition of a specific speed regulating float. DETAILED DESCRIPTION

[0021] To make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail below in combination with specific implementations and with reference to the accompanying drawings. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0022] It is to be understood that these descriptions are exemplary only and are not intended to limit the scope of the invention.

[0023] Some embodiments of the present invention are described below in conjunction with the accompanying drawings.

[0024] Reference Figure 1-11A method of buoyancy-assisted gravity energy storage for use at sea, the method comprising: establishing a mobile or fixed marine platform at sea, installing a pulley block and a motor unit on the marine platform, passing a first transmission cable linked to the motor unit through the pulley block, a speed regulating float being fixed at one end of the first transmission cable, a deceleration buffer device being fixed at the other end, and a weight being installed at the lower end of the speed regulating float. In the initial state, the weight sinks on the seabed or hangs in the sea water and is located at a low point. When storing energy, the electric power drives the motor unit to lift the weight to a high point and fix it, converting the electrical energy into potential energy and storing it. When releasing energy, the weight is released and sinks under the action of gravity. After the speed regulating float contacts the sea water, the sinking speed of the weight is adjusted by the speed regulating float until it sinks at a uniform speed. Finally, the deceleration buffer device controls the weight to buffer and decelerate until it stops, so that the weight returns to a low point. During the sinking process of the weight, the first transmission cable drives the motor unit to generate electricity, converting the potential energy into electrical energy, and realizing buoyancy-assisted gravity electrical energy storage through energy storage and release cycles.

[0025] A buoyancy-assisted gravity energy storage device for use at sea, comprising a mobile or fixed marine platform 1 established at sea, a pulley block and a motor unit installed on the marine platform 1, a first transmission cable 2 linked to the motor unit is passed through the pulley block, a speed regulating float 3 is fixed to one end of the first transmission cable 2, a deceleration buffer device 5 is fixed to the other end, and a weight 4 is installed at the lower end of the speed regulating float 3.

[0026] The marine platform 1 can be a fixed platform on the seawater, such as a booster tank of offshore wind power, an oil drilling platform, etc., or a floating body on the sea, such as a large ship. It has little impact on the inland environment, will not occupy farmland or land, and will not affect the surrounding transportation and production and living environment. The vast sea area provides sufficient space and there is no need to worry about occupation issues. There is no need to build high towers or dig deep wells like energy storage projects such as solid gravity potential energy storage. Only the characteristics of the ocean depth can be used to easily solve the space problem of rising and falling heavy objects, which is more suitable for large-scale engineering construction.

[0027] The corresponding fixing devices and power generation devices of the present invention are all installed on the marine platform 1. If electrical equipment such as motors are in contact with seawater for a long time, they require frequent maintenance and their service life will be greatly reduced.

[0028] The pulley group includes a first pulley 6, a second pulley 7, a third pulley 8, and a fourth pulley 9. The third pulley 8 and the fourth pulley 9 have the same installation height, and the second pulley 7 has the lowest installation height. The first transmission cable 2 passes through the first pulley 6, the second pulley 7, the third pulley 8, and the fourth pulley 9 in sequence, and the second pulley 7 is connected to the motor unit in terms of transmission.

[0029] refer to Figure 1-6 In this embodiment, the installation heights of the first pulley 6, the third pulley 8 and the fourth pulley 9 are consistent, the installation height of the second pulley 7 is lower than these three pulleys, and the two sides of the second pulley 7 are parallel to the tangent lines of the first pulley 6 and the third pulley 8. When the first transmission cable 2 passes through each pulley, the central angle of the second pulley 7 wrapped and covered by the first transmission cable 2 reaches 180°, and the torque transmission to the shaft is more balanced. The arrangement here can improve the stability and safety of the system operation.

[0030] In addition, the present invention may also adopt different pulley block designs, as long as the same effect can be achieved.

[0031] The motor unit comprises a generator motor unit 10 and a drive motor unit 11 , wherein the generator motor unit 10 and the drive motor unit 11 are connected to a first gear 12 via a clutch transmission gearbox, and the first gear 12 rotates synchronously with the second pulley 7 .

[0032] refer to Figure 5 The clutch transmission gearbox includes a clutch gear 28, a speed increasing gear set 29, and a speed reducing gear set 30. The clutch gear 28 is always meshed with the first gear 12. The output shaft of the generator motor unit 10 is connected to a second gear 32 through a coupling 31. The second gear 32 is meshed with the speed increasing gear set 29. The output shaft of the drive motor unit 11 is fixed with a third gear 33. The third gear 33 is meshed with the speed reducing gear set 30. When the clutch gear 28 is turned to mesh with the speed reducing gear set 30, the drive motor unit 11 A transmission connection is formed with the present device. At this time, the driving motor unit 11 is driven to start, so that the weight 4 can be lifted up, and due to the action of the reduction gear set 30, the rotation speed of the first gear 12 is reduced and its torque is increased, thereby providing sufficient protection for lifting the weight 4; when the clutch gear 28 is turned to engage with the speed-increasing gear set 29, that is, the generator motor unit 10 forms a transmission connection with the present device, the weight 4 is released at this time, and the weight 4 sinks, driving the generator motor unit 10 to rotate, thereby realizing the function of power generation. Due to the resistance of the seawater itself, the sinking speed of the weight 4 is relatively slow. The speed-increasing gear set 29 is used to increase the rotation speed of the generator motor unit 10 so that it meets the speed requirement for power generation. In actual applications, gear sets with different tooth ratios can be configured according to the actual required power generation and power generation efficiency.

[0033] A weight launching area 13 is provided on the marine platform 1 corresponding to the weight 4, and a movable load-bearing plate 14 for placing the weight 4 is installed on the weight launching area 13. A groove 15 similar to the lower end of the weight 4 is provided in the middle of the load-bearing plate 14, and the lower end of the weight 4 is placed on the groove 15, and an elastic buffer pad 16 is placed between the weight 4 and the groove 15 to ensure that the weight 4 does not slide, thereby further improving the stability and safety of the system operation.

[0034] The heavy object launching area 13 can be rectangular, and the load-bearing plate 14 can be translated along the length direction on the heavy object launching area 13. When the heavy object 4 needs to be placed, the load-bearing plate 14 can be moved to the bottom of the heavy object 4. When the heavy object 4 needs to be launched into the water, the load-bearing plate 14 can be removed from the heavy object launching area 13. The load-bearing plate 14 can also be composed of two suspension bridges. When the heavy object 4 needs to be placed, the two suspension bridges are lowered, and the heavy object 4 is placed on the suspension bridges. The structure is simple and suitable for the construction of large-scale projects. In addition, conventional methods such as a crane can be used to move the heavy object 4 from the top of the heavy object launching area 13 to other positions of the offshore platform for placement.

[0035] In this system, a flywheel energy storage system can be connected in series. When the sinking speed of the weight 4 fluctuates, the flywheel energy storage system can absorb or release energy to maintain a relatively stable speed of the entire system, thereby ensuring that the weight 4 moves at a uniform speed, further improving the stability of power generation.

[0036] Example 1: Reference Figure 1 , 2 The deceleration buffer device 5 includes a slide rail seat 17 and a buffer float 22 installed on the marine platform 1. A slider 19 pushed downward by a spring 18 is installed in the slide rail seat 17. A through hole 20 is provided at the center of the slider 19. A block 21 is installed after the first transmission cable 2 passes through the through hole 20. The size of the block 21 is larger than the size of the through hole 20. The buffer float 22 is connected to the slider 19 through a first reversing wheel 23 and a second transmission cable 34.

[0037] The first reversing wheel 23 is fixed on the marine platform 1. When the weight 4 sinks to a position close to the low point, the block 21 at the end of the first transmission cable 2 is stuck in the through hole 20, thereby driving the slider 19 to move upward together, and finally the buffer float 22 is pulled down by the first reversing wheel 23 and the second transmission cable 34. The drainage area of ​​the buffer float 22 increases, and the buoyancy gradually increases. A gradually increasing pulling force is applied to the weight 4 through the first transmission cable, so that the weight 4 gradually slows down until it stops, further improving the stability and safety of the device.

[0038] In this embodiment, the buffer float 22 is dragged downward, so the height of the first diverting wheel 23 is located below the buffer float 22, and the buffer float 22 is located under the sea, so the first diverting wheel 23 needs to be set in the sea.

[0039] Example 2: Reference Figure 3 , 4 The deceleration buffer device 5 includes a second reversing wheel group 44, a third reversing wheel group 45, a slide rail seat 17 installed on the marine platform 1, and a buffer float 22. A slider 19 pushed downward by a spring 18 is installed in the slide rail seat 17. A through hole 20 is arranged at the center of the slider 19. A clamping block 21 is installed after the first transmission cable 2 passes through the through hole 20. The size of the clamping block 21 is larger than the size of the through hole 20. A first counterweight block 35 is installed between the second reversing wheel group 44 and the third reversing wheel group 45. A third transmission cable 36 is passed through the second reversing wheel group 44 to connect the first counterweight block 35 with the slider 19. A fourth transmission cable 42 is passed through the third reversing wheel group 45 to connect the first counterweight block 35 with the buffer float 22. A second counterweight block 37 with the same gravity as the first counterweight block 35 is installed on the buffer float 22.

[0040] The second redirecting wheel group 44 includes a second redirecting wheel 38 and a third redirecting wheel 39. The second redirecting wheel 38 is installed at a lower position of the marine platform 1, such as on the ground. The third redirecting wheel 39 is installed at a high position of the marine platform 1. The third redirecting wheel group 45 includes a fourth redirecting wheel 40 and a fifth redirecting wheel 41. The fourth redirecting wheel 40 and the fifth redirecting wheel 41 are at the same height as the third redirecting wheel 39. After installation, the first counterweight block 35 is lower than the third redirecting wheel 39 and the fourth redirecting wheel 40.

[0041] In the initial state, the tension of the first counterweight block 35 on the third transmission cable 36 is 0, the gravity of the second counterweight block 37 acts on the first counterweight block 35 through the fourth transmission cable 42 and reaches a balance, and the buffer float 22 floats on the water surface (it can be understood that the third transmission cable 36 is not tightened, and the first counterweight block 35 is pulled up by the second counterweight block 37, as shown in FIG. Figure 3 As shown in B, the first counterweight block 35 is tilted toward one side of the third transmission cable 36 as a whole), at this time, the buoyancy of the buffer float 22 is equal to its own weight. When deceleration is required, the slider 19 rises and pulls up the first counterweight block 35 through the third transmission cable 36. At this time, the tension on the third transmission cable 36 gradually increases from 0, and the first counterweight block 35 changes from an inclined state to a parallel state. Correspondingly, the tension of the fourth transmission cable 42 on the first counterweight block 35 is reduced, and the gravity of the second counterweight block 37 remains unchanged, that is, the balance between the second counterweight block 37 and the first counterweight block 35 is broken, and the second counterweight block 37 begins to sink. , the buffer float 22 descends synchronously, and its displacement volume increases, thereby increasing the buoyancy, thereby maintaining the balance between the second counterweight block 37 and the first counterweight block 35. As the tension on the third transmission cable 36 gradually increases and acts on the weight 4 through the first transmission cable 2, the weight 4 changes from a balanced state (that is, the uniform motion stage of the weight 4) to an upward pulling force, thereby starting to decelerate until it stops. That is, the actual deceleration process is to gradually convert the tension on the fourth transmission cable 42 into the tension on the third transmission cable 36, which then acts on the weight 4 through the first transmission cable 2, so that the weight 4 achieves a deceleration effect.

[0042] The deceleration process of Examples 1 and 2 is not an instantaneous process, but a process in which the weight 4 is gradually decelerated as the pulling force gradually increases and acts on the weight 4. This is a flexible process, so there is less damage to the transmission cable. The buffer float 22 can be a closed cavity or a float with an open upper end (such as a ship), but it is necessary to ensure that during the operation of the entire system, no water can enter the interior of the float, causing the entire float to sink completely, thereby affecting the size of the buoyancy.

[0043] A spring washer 24 is fixed to the end of the spring 18. When the slider 19 rises, it will first contact the spring washer 24 and then compress the spring 18. At this time, the restoring force generated by the spring 18 is also opposite to the direction of movement of the weight 4, that is, the restoring force also plays a role in buffering and deceleration.

[0044] In embodiments 1 and 2, the buffering and decelerating function of the buffering float 22 can be used independently, and the buffering and decelerating function of the spring 18 can be used independently, but the service life of the spring is short, and the two can also be used together.

[0045] Embodiment 3: The deceleration buffer device 5 includes a winch bracket 25, on which a winch drum 27 driven by a take-up motor 26 is installed. The first transmission cable 2 is wound around the winch drum 27, and the end of the first transmission cable 2 is fixed on the marine platform 1. Even when the first transmission cable 2 on the winch drum 27 is completely released and the weight 4 has not stopped, the force transmitted by the weight 4 through the first transmission cable 2 directly acts on the marine platform 1, thereby further improving the protection of the winch drum 27.

[0046] Through the intervention of external power, the generator motor unit 10 is controlled to produce an excitation effect, thereby providing a torque in the opposite direction, which is finally transmitted to the weight 4 through the first transmission cable 2, so that the weight 4 needs to overcome increasingly greater resistance to descend, and finally slowly stops.

[0047] like Figure 6 As shown, the winch drum 27 is of a short-axis type. When the winch drum 27 rotates, the first transmission cable 2 can be retracted and released.

[0048] like Figure 5 As shown, the winch drum 27 is of a long axis type, and the left and right ends of the rotating shaft of the winch drum 27 adopt threaded shafts. When the winch drum 27 rotates, the threaded shaft controls the winch drum 27 to move to the left or right, and the middle part of the shaft is a bare rod for winding the first transmission cable 2. When the winch drum 27 retracts and releases the first transmission cable 2, the winch drum 27 will move synchronously to the left or right, so that for each winding of the first transmission cable 2, the rotating shaft will move a distance (i.e., the pitch of the threaded shaft), thereby avoiding a large number of first transmission cables 2 from being wound on the same position of the rotating shaft, and evenly winding the first transmission cable 2 on the rotating shaft, so that the force on the rotating shaft is relatively balanced, thereby improving the service life of the rotating shaft.

[0049] The length and diameter of the bare rod are mainly determined by the energy storage limit of the weight 4. After the weight 4 reaches the highest height, the first transmission cable 2 can just wrap around the bare rod.

[0050] It should be noted that when the first transmission cable 2 is wound around the light rod, there is a small gap between the first transmission cables 2, so that the first transmission cables 2 will not be tightly attached to each other, and further the first transmission cables 2 can be more evenly distributed and wound around the entire light rod. It is necessary to calculate based on the diameter of the first transmission cable 2 and the position moved when the rotating shaft rotates one circle. The length and diameter of the light rod here are just a relatively close design, and there is no restriction on the specific size and geometric shape parameters.

[0051] The complete energy storage steps of the present invention are: S1: In the initial state, the weight is sunk on the seabed or hanging in the seawater, and is located at a low point. The clutch speed change gearbox is adjusted to become a reduction gearbox, and is connected to the drive motor unit 11 by transmission. The drive motor unit 11 is driven by the power supply / network to pull the weight 4 to a high point (this process is carried out when the electricity price is relatively cheap, so as to store energy at the lowest cost), and is initially fixed; S2: Move the load-bearing plate 14 to cover the weight launching area 13, and reversely drive the driving motor unit 11 to slowly lower the weight 4 until the weight 4 is placed in the groove 15; The complete energy release steps of the present invention are: A1: The driving motor unit 11 drives the weight 4 to be lifted and completely removed from the groove 15 and initially fixed; A2: Remove the load-bearing plate 14 from the heavy object launching area 13; A3: Adjust the clutch speed change gearbox to make it an acceleration gearbox and connect it to the generator motor unit 10; A4: releasing the weight 4, and the speed regulating float 3 assists the weight 4 to sink at a uniform speed, and drives the clutch speed change gear box through the first transmission cable 2, thereby driving the generator motor unit 10 to rotate and generate electricity; A5: The deceleration buffer device 5 controls the weight 4 to buffer and decelerate until it stops.

[0052] In the present invention, the movement of the weight 4 includes an initial acceleration stage, a mid-term uniform speed stage and a late deceleration stage, wherein the uniform speed stage is suitable for power generation, so it is necessary to maximize the time of the uniform speed stage, and the weight 4 needs to achieve a balance in its own force to reach the uniform speed stage. The weight 4 is subject to gravity G and buoyancy F1. When the weight 4 sinks, it will also be subject to a flow resistance F2. Under the conditions of the same material and geometric dimensions, the flow resistance encountered by the weight 4 when sinking is positively correlated with the instantaneous sinking speed and the medium density. Therefore, when the weight sinks, with seawater as the medium, the weight 4 will be subject to a flow resistance far greater than that provided by air. That is, in theory, after the weight 4 sinks to a certain depth, the gravity G, buoyancy F1 and flow resistance F2 can reach a balance (i.e., G=F1+F2), and the sinking motion of the weight 4 becomes a uniform motion. The work done at this time can be used for power generation.

[0053] However, this acceleration process will take a long time, which is equivalent to the weight 4 falling a very deep distance where it cannot do work. At the same time, this also requires a longer first transmission cable 2 to ensure the efficiency of power generation, which will significantly increase the construction cost. In order to solve this technical problem: in the absence of external power intervention control, the weight 4 can be made to move at a uniform speed faster. In this method, the speed regulating float 3 is connected above the weight 4. When the speed regulating float 3 sinks into the water, two forces can be provided to the weight 4: the buoyancy F3 generated by the discharge of the speed regulating float 3 and the flow resistance F4 of the speed regulating float 3 during the sinking movement (the weight of the speed regulating float 3 is too small compared to the weight and can be ignored). By introducing the two new forces F3 and F4, the weight 4 can reach a uniform speed faster. Similarly, the acceleration process of the weight 4 will be further shortened to greatly reduce the distance where it cannot do work to generate electricity, that is, to improve the efficiency of converting gravitational potential energy into electrical energy in this method. At this time, the force on the weight 4 is: G=F1+F2+F3+F4.

[0054] In the present invention, the speed regulating float 3 and the weight 4 are connected by a fifth transmission cable 43, which has a certain length. Assuming that when the speed of the weight 4 reaches 10m / s, the speed regulating float 3 can make the weight 4 reach a uniform speed. After adding the speed regulating float 3, the acceleration of the weight 4 will decrease. Therefore, the optimal solution is that in the acceleration stage, only the weight 4 is moving. When the speed regulating float 3 just joins the movement of the weight 4 (the moment when the speed regulating float 3 is completely submerged in the water), the weight 4 enters the uniform speed stage. Therefore, in the initial stage, the The speed regulating float 3 is placed on the marine platform 1. When the weight 4 starts to sink and reaches a uniform speed, the speed regulating float 3 is just pulled into the water through the fifth transmission cable 43. Therefore, the fifth transmission cable 43 needs to meet this requirement. At this time, the force on the weight 4 is changed from its own gravity G, buoyancy F1 and flow resistance F2 to its own gravity G, buoyancy F1, flow resistance F2 and the buoyancy F3 and flow resistance F4 of the speed regulating float 3 (the flow resistance is related to the parameters of the object (length, width, height, density of the flowing medium, speed, etc.)

[0055] The weight 4 in the present application is a double-bullet-shaped cylinder, which is close to a long ellipsoid with the same length and width. The volume of a double-bullet-shaped cylinder can be calculated by the following steps: the dimensions of an ellipsoid usually include length (L), width (W) and height (H).

[0056] The volume V can be calculated as: V = (2π × LWH) / 9. The double bullet-shaped cylinder in this application can be understood as an ellipsoid whose cross section in the vertical direction is a circle. Therefore, assuming that the radius of the most central cross section, i.e., the largest cross section, is R', the above formula can be transformed into: V = (2π × R' 2 H)∕9.

[0057] Assume that the weight is 100 tons and the material is lead. The density of lead is 11.34×10 3 kg / m³, then the volume of 100 tons of lead is about 8.82m³, then according to the above formula V=(2π×R' 2 H)∕9, it can be inferred that the relationship between radius and height is approximately R' 2 H=12.6337, that is, when the maximum cross-sectional radius of the weight is selected as R' of 1.5m, the height H of the weight is about 5.61m.

[0058] Since the weight in this application is a large weight, the flow resistance only considers the wave resistance and ignores the viscous resistance, so the flow resistance F2=0.5ρv 2 C dA, where ρ represents the density of seawater. The density of seawater under standard conditions (i.e., temperature of 4 degrees Celsius and salinity of 35%) is approximately 1.025×10 3 kg / m³, C d It represents the drag coefficient of the object (this weight is a double-bullet-shaped cylinder with the bullets at both ends tending to be streamlined, and the general coefficient is 0.5 to 1). The coefficient here is taken as the middle value of 0.75. A represents the cross-sectional area of ​​the weight in the direction of its movement speed in the seawater. Since R' is 1.5m, the area A is approximately 7.0686m², and v represents the speed of the weight in the seawater.

[0059] The speed of a weight when it falls uniformly in seawater is also called the terminal velocity Vt. At this time, the acceleration due to gravity g is taken as 9.8m / s². From the above, we can infer that after the weight is completely submerged in water, the buoyancy of the weight itself is F1=ρgV=88597N, and the gravity of the weight itself is G=mg=980000N.

[0060] According to the empirical formula:

[0061] Without the introduction of the speed regulating float 3, the weight 4 needs to be accelerated to 18.11 m / s before reaching the uniform speed stage.

[0062] According to v=at, a is acceleration, and t is acceleration time, we can construct the following calculation formula:

[0063] After the speed regulating float 3 is introduced, assuming that the radius of the speed regulating float 3 is 1.5m, its volume is 14.14m³, the buoyancy F3 provided is 142036N, and the flow resistance F4 will also be a function that changes with the speed. The spherical resistance coefficient C d According to the manual, it is 0.5, so its flow buoyancy is 1811.32v². At this time, the formula of the above-mentioned overall weight speed v with respect to time t becomes:

[0064] Considering that the speed v changes with the falling time t, the calculation is difficult, so the MATLAB programming method is used to obtain the curve of the speed change with time as shown below: Fig.10 shown.

[0065] Although the current scheme has added the speed regulating float 3 to provide additional resistance to the weight 4, it has reduced the time for the weight 4 to reach a uniform speed to a certain extent. As can be seen from the figure, without the speed regulating float 3, the weight needs to sink for 80 seconds before gradually tending to uniform motion (that is, the change in speed is no longer obvious compared to before), and after adding the speed regulating float 3, the weight tends to move at a uniform speed after sinking for about 40 seconds, which is reduced by about 40 seconds. However, considering that the speed of the weight is very fast, the weight with the speed regulating float 3 sinks about 434m in the first 40s of accelerated motion, which means that 434m of height is wasted. Therefore, the simple introduction of the speed regulating float 3 is still not enough to reduce the acceleration time. In the specific implementation process, too much unused gravitational potential energy will still be consumed. Moreover, the simple introduction of the speed regulating float 3 can only make a rough judgment on the specific time to reach a uniform speed based on the trend, and there is no accurate and reliable data.

[0066] So we need to design a shorter and more accurate acceleration time. The following is the improved calculation method: First, we need to preset a uniform speed required for the weight. For example, suppose the weight 4 needs to be accelerated to 10m / s (that is, the weight 4 can enter the uniform speed stage by artificially controlling it to reach 10m / s), and the subsequent uniform work is used to generate electricity, that is, before the weight 4 reaches 10m / s, the speed regulating float 3 has not entered the water. At this time, the speed change function with respect to time can be calculated by the above formula.

[0067] After calculation through MATLAB, it can be known that it takes 2.92s to accelerate to this speed. By integrating the speed curve, it can be known that when it reaches 2.92s, the total distance traveled is 6.33m, so the length L of the fifth transmission cable 43 connecting the weight 4 and the speed regulating float 3 is 6.33m.

[0068] Ignoring the time it takes for the speed regulating float 3 to be completely immersed in water and the deadweight of the speed regulating float 3, if it is required that the heavy object descends at a uniform speed after the speed regulating float 3 is completely immersed, a specific design of the geometric dimensions of the speed regulating float 3 is required.

[0069] According to the principle of the method of the present application, the weight 4 is balanced by the buoyancy F3 and flow resistance F4 additionally provided by the external speed regulating float 3; assuming that the designed radius of the speed regulating float 3 is R, it can be calculated by the relationship G=F1+F2+F3+F4: 619704.32-80503.31R²-42076.4R³=0 That is the design method of the speed regulating float 3 described in this patent. Since this equation is relatively complicated, we can use MATLAB's fzero function, which is a function used to find the zero point of a nonlinear equation, and solve it to get R=1.952m.

[0070] The curve drawn by MATLAB again is as follows Fig.11 shown.

[0071] That is, ignoring the time for the weight and the speed regulating float 3 to sink, when the radius of the speed regulating float 3 is designed to be 1.952m, the weight is accelerated to 10m / s after the weight has descended for 2.92s. By solving the integral, it can be known that the weight has descended a total of 6.33m during this period of time, that is, the length L of the fifth transmission cable 43 connecting the speed regulating float 3 and the weight 4 is 6.33m. The speed regulating float 3 of this particular design and the specific length L can make the weight accelerate to 10m / s, and then the speed regulating float 3 is dragged into the water, and thereafter the weight has been sinking at a uniform speed of 10m / s.

[0072] Depend on Fig.10 and Fig.11 It can be seen that compared with the traditional solution without the speed regulating float 3 and the solution without designing the speed regulating float 3 of a specific size, the new solution can make the heavy object reach uniform motion more quickly, saving more gravitational potential energy that was originally wasted, and further improving the energy conversion efficiency.

[0073] In the present invention, the term "plurality" means two or more than two, unless otherwise clearly defined. The term "and / or" used herein includes any and all combinations of one or more of the related listed items. The terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "connect" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0074] It should be noted that when an element is referred to as being "assembled on", "installed on", "fixed on" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0075] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0076] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for buoyancy-assisted gravity energy storage for offshore use, characterized in that The method is as follows: a mobile or fixed marine platform is established at sea, a pulley block and a motor unit are installed on the marine platform, a first transmission cable linked with the motor unit is passed through the pulley block, a speed regulating float is fixed at one end of the first transmission cable, a deceleration buffer device is fixed at the other end, and a weight is installed at the lower end of the speed regulating float. In the initial state, the weight is sunk on the seabed or suspended in the sea water, and is located at a low point. During energy storage, the motor unit is driven by electricity to lift the weight to a high point and fix it, and the electrical energy is converted into potential energy and stored. During energy release, the weight is released, and the weight sinks under the action of gravity. After the speed regulating float contacts the sea water, the sinking speed of the weight is adjusted by the speed regulating float until it sinks at a uniform speed. Finally, the deceleration buffer device controls the weight to buffer and decelerate until it stops, so that the weight returns to the low point. During the sinking process of the weight, the first transmission cable drives the motor unit to generate electricity, converting the potential energy into electrical energy, and realizing the buoyancy-assisted gravity electrical energy storage through the energy storage and energy release cycle.

2. A buoyancy-assisted gravity energy storage device for use at sea, characterized in that , comprising a mobile or fixed marine platform (1) established at sea, a pulley block and a motor unit installed on the marine platform (1), a first transmission cable (2) linked to the motor unit passing through the pulley block, a speed regulating float (3) fixed at one end of the first transmission cable (2), a deceleration buffer device (5) fixed at the other end, and a weight (4) installed at the lower end of the speed regulating float (3).

3. The buoyancy-assisted gravity energy storage device for use at sea according to claim 2, characterized in that The pulley block comprises a first pulley (6), a second pulley (7), a third pulley (8), and a fourth pulley (9); the third pulley (8) and the fourth pulley (9) are installed at the same height, and the second pulley (7) has the lowest installation height; the first transmission cable (2) passes through the first pulley (6), the second pulley (7), the third pulley (8), and the fourth pulley (9) in sequence; and the second pulley (7) is transmission-connected to the motor unit.

4. The buoyancy-assisted gravity energy storage device for use at sea according to claim 3, characterized in that The motor unit comprises a generator motor unit (10) and a drive motor unit (11); the generator motor unit (10) and the drive motor unit (11) are connected to a first gear (12) via a clutch transmission gearbox; the first gear (12) rotates synchronously with the second pulley (7).

5. The buoyancy-assisted gravity energy storage device for use at sea according to claim 2, characterized in that The offshore platform (1) is provided with a weight launching area (13) corresponding to the weight (4), and a movable bearing plate (14) for placing the weight (4) is installed on the weight launching area (13). A groove (15) similar to the lower end of the weight (4) is provided in the middle of the bearing plate (14), and the lower end of the weight (4) is placed on the groove (15), and an elastic buffer pad (16) is placed between the weight (4) and the groove (15).

6. The buoyancy-assisted gravity energy storage device for use at sea according to claim 2, characterized in that The deceleration buffer device (5) comprises a slide rail seat (17) and a buffer float (22) installed on the offshore platform (1); a slider (19) pushed downward by a spring (18) is installed in the slide rail seat (17); a through hole (20) is provided at the center of the slider (19); a clamping block (21) is installed after the first transmission cable (2) passes through the through hole (20); the size of the clamping block (21) is larger than the size of the through hole (20); and the buffer float (22) is connected to the slider (19) via a first reversing wheel (23) and a second transmission cable (34).

7. The buoyancy-assisted gravity energy storage device for use at sea according to claim 2, characterized in that The deceleration and buffer device (5) comprises a second reversing wheel group (44), a third reversing wheel group (45), a slide rail seat (17) installed on the offshore platform (1), and a buffer float (22); a slider (19) pushed downward by a spring (18) is installed in the slide rail seat (17); a through hole (20) is provided at the center of the slider (19); a clamping block (21) is installed after the first transmission cable (2) passes through the through hole (20); the size of the clamping block (21) is larger than the size of the through hole (20); A first counterweight (35) is installed between the second reversing wheel group (44) and the third reversing wheel group (45); a third transmission cable (36) is passed through the second reversing wheel group (44) to connect the first counterweight (35) with the slider (19); a fourth transmission cable (42) is passed through the third reversing wheel group (45) to connect the first counterweight (35) with the buffer float (22); and a second counterweight (37) having the same gravity as the first counterweight (35) is installed on the buffer float (22).

8. The buoyancy-assisted gravity energy storage device for use at sea according to claim 6 or 7, characterized in that A spring washer (24) is fixed to the end of the spring (18).

9. The buoyancy-assisted gravity energy storage device for use at sea according to claim 2, characterized in that The deceleration buffer device (5) comprises a winch bracket (25), a winch drum (27) driven by a take-up motor (26) is mounted on the winch bracket (25), and the first transmission cable (2) is wound around the winch drum (27).

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