ES2648521B1 - Potential energy storage system and electric power generation - Google Patents

Abstract

Potential energy storage and electric power generation system # The system comprises at least one mobile platform (1) movable between an upper (A) and lower (B) position, the platform (1) being supported by a set of actuators (2) hydraulic and configured to receive an active weight (6), so that the platform (1) with the active weight (6) is able to descend due to gravity to the lower position (B), causing its once a pushing force on the actuator assembly (2); at least one accumulator tank (7) of potential energy capable of storing the volume of fluid (5) driven by the set of actuators (2) and capable of discharging the volume of fluid stored to a turbine (9) connected to an electric generator (10); and a recovery tank (11) provided for storing the fluid from the turbine (9) and recirculating it towards the set of actuators (2) that allow the empty platform (1) to be lifted to the upper position (A).

Description

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DESCRIPTION

Potential energy storage system and electric power generation Technical sector of the invention

The invention relates to a potential energy storage system and electric power generation. The invention also relates to a parking facility for land transport vehicles comprising said system.

Background of the invention

It is foreseeable that international commitments in the field of greenhouse gas reduction will establish, and make effective, increasingly restrictive imperatives regarding the scope of electricity production from fossil fuels, which will result in a greater investment in renewable energy, those that do not produce adverse effects on the atmosphere or the environment.

The intensive demand for electricity as a result of industrial activity, among other particular criteria, imposes massive means of electricity production, such as that offered by thermal power plants, which can guarantee the continuous and sustained power supply. This circumstance, coupled with the intermittent availability of removable energy from natural environments, limits the possibilities of coverage of the demand through renewable sources.

The inability to store the electricity produced in an economically viable way also presents an important challenge, which has an economic impact that is explained by the mismatch of supply with demand. Certain technologies are capable of tackling that limitation, as is the case with a number of hydroelectric plants with the capacity to operate reversibly, turbining (and therefore generating electricity) in hours of electricity demand, and consuming electricity to pump previously turbined water. during night time, when the low or no demand implies proportionally low or perhaps nonexistent electricity costs. Water pumping is equivalent to endowing with potential energy with a higher net energy expenditure, which however is at a cost

marginal, while reserving water to produce electricity at times when

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Demand, and therefore the price of kW, is higher.

The need to find solutions that reconcile economic and ecological interests affects the entire chain of the electrical system, from electricity generation technology to efficient consumption.

Patent application WO2015027113 A1 refers to a system and method for storing potential energy, capable of generating electricity from the force of gravity, which comprises a sliding piston inside a hollow cylinder, whose walls define an internal volume containing a liquid, a sealing gasket disposed between the piston and the cylinder walls, and a liquid conduit in communication with the cylinder. The piston divides the inner volume into a first upper chamber and a second lower chamber, both chambers being intercommunicated through the conduit. The system further comprises a reversible pump / turbine operatively coupled in the liquid conduit to drive a reversible motor / generator, and control valves. The piston is capable of moving inside the cylinder between a raised position to a lower position.

When the piston is in the lower position, the turbine stops working so that the energy generated is used to drive the pump motor which in turn drives the liquid through the conduit from the upper chamber to the lower chamber, thus increasing the pressure in the lower chamber under the piston. The pressure difference causes the piston to rise until it reaches the elevated position, with potential energy being stored in the system. Then, the pump stops working so that the potential energy stored allows the piston to descend, the weight of which drives the liquid into the duct from the lower chamber into the upper chamber so that the liquid flows through the turbine thus driving the generator to produce electrical energy, which can be used in a power plant. This system can be used, for example, to store potential energy that has been generated during the hours of lower demand for electricity consumption.

EP1409876 B1 refers to a potential energy storage system, which describes an energy conversion system that can supply electrical energy to similar buildings or structures, such as a parking lot. The system comprises a

plurality of hydraulic cylinders distributed in the foundations of a building, being the

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pistons of the respective cylinders mounted under two supporting columns of the building structure, a conduit that supplies fluid to the cylinders, a reservoir of fluid connected to said conduit, control valves, and a reversible pump / turbine connected between the duct and reservoir. In this way, when the pistons descend by the action of the weight of a platform that constitutes the floor of the building, the pressurized fluid is conducted through the duct to the turbine generating electricity, and storing the fluid in the reservoir, while when the pump is operated the fluid stored in said tank is propelled towards the cylinders to raise the structure of the building again, storing potential energy again. This system can be used to satisfy the building's electricity consumption during the hours of greatest demand during the day.

It should be noted that the aforementioned patent documents WO2015027113 A1 and EP1409876 B1 respectively describe a system provided with a reversible pump / turbine, analogous to that of a reversible hydroelectric plant, which requires electricity to drive the pump to raise the piston in order to recover potential energy , the pump being the same turbine with reverse rotation. However, the overall efficiency of the cycle is negative since less energy is extracted from that supplied, although on the other hand economic profitability is obtained by feeding with the surplus of energy and producing during high demand hours, when the price of kWh is older.

Other systems that take advantage of the force of gravity provided by the weight of a vehicle or set of vehicles are also known, as described in the patent documents cited below.

The utility model ES1069011U refers to a system of harnessing the force of gravity through car parks to generate energy and / or pumping fluids or gases. This system comprises a lever that pivots through its midpoint on a point of support, being joined in an articulated manner at its ends to two platforms, so that said platforms can maintain their horizontal position during the alternating vertical movement to which they are subjected. Each platform is intended to receive the weight of transport vehicles that are parked for a period of time and can access these platforms through ramps articulated to the ends of each platform and supported on the ground through

wheels. The platforms act in turn on one or more hydraulic cylinders that can

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absorb movement to create pressures.

The vehicles can access through the respective ramp to the platform that is at its highest point, so that its weight will allow the platform to descend, exerting pressure on the associated hydraulic cylinders, which through some ducts they drive a fluid that can act on a turbine and this in turn on an electric power generator. The turbine outlet is connected to the cylinders associated with the other platform. Each cylinder also has a valve to open or close the circuit and thus be able to stop or start the vertical movement of the platforms alternately, so that while the platform with the parked vehicles descends by operating the turbine, the other empty platform ascends by the action of its cylinders that receive the fluid that leaves from the turbine, which will allow its ascent to the upper level to receive other vehicles that will park on it, repeating the cycle successively.

The patent MX2013013305 A refers to an apparatus for absorbing vibrations and for converting the kinetic energy generated by the passage of moving and pedestrian vehicles while decelerating. The kinetic energy received is converted into potential energy using a restorable elastic element that compresses a fluid, thereby storing the potential energy in a pressure chamber, so that the pressurized fluid is conducted through a check valve along a duct to move a paddle wheel by releasing potential energy. Said paddle wheel drives an electric power generator. Vehicle vibration is mitigated by the damping effect provided by the device.

The utility model ES1025970 U refers to a device for transforming mechanical energy into electrical energy, which comprises a deformable metal surface that covers a recess made in the pavement, such as the entrance or exit of a parking lot. Said metal surface is coupled on an elastic element which, by means of a rack-and-pinion mechanism coupled to a driving axle, allows the vertical movement of the platform when a car passes through it, so that said vertical displacement is transformed into rotation. of the drive shaft to which an alternator that generates electric power is connected.

However, the potential energy generated, either by the action of vehicle weight

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stationed on the alternating platforms, or where appropriate by repeated percussion or vibration when passing vehicles, it is used directly to drive an electric generator, without the possibility of storing energy for later use.

It would be desirable to have a system that allows to take advantage of the force of gravity, due to the reduction of a weight, whose potential energy allows generating electrical energy, but without the need to provide the electricity system to lift said weight and restore the potential energy assigned, and which in turn allows to store the potential energy generated for a period of time, either to keep it as a reserve or to generate electricity immediately and continuously.

Explanation of the invention.

In order to provide a solution to the problems raised, a potential energy storage and electric power generation system is disclosed, configured by a hydraulic circuit comprising at least one mobile platform capable of moving according to an alternative movement between a position upper and lower position, the platform being supported by a set of hydraulic actuators provided with at least one cylinder-piston whose cylinder chamber contains a volume of hydraulic fluid, and the platform being configured to receive an active weight on its surface, it being understood by weight, a mass with its own motor capacity whose impulse allows it to be positioned on the platform in the upper position and to leave said platform in the lower position, so that the platform loaded with the active weight is able to descend due to the effect of the gravity steadily to the lower position, causing in turn a force of thrust on the set of actuators.

The system is characterized in that it comprises at least one potential energy storage tank capable of storing the volume of fluid driven by the set of actuators during a predetermined number of descent cycles of the platform loaded with the active weight, said storage tank being provided with a weight arranged floating above the level of the stored fluid to exert a predetermined hydraulic pressure, and said accumulator tank being able to discharge the volume of stored fluid to a turbine, which in turn is connected to an electric generator to produce electricity; a set of valves actuated by means of

control; and a recovery tank intended to store the fluid from the

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turbine and recirculate it towards the set of actuators, closing the circuit, so that said set of actuators is capable of exerting a pushing force on the empty platform, devoid of the active weight, to propel it from the lower position to the upper position, remaining thus prepared to receive another active weight.

Therefore, the system of the present invention allows generating electricity from the force of gravity as a source of supply energy, whose operation contemplates a first phase of charging and storage of potential energy, using an active weight, such as for example vehicles of land transport, whose flow is available by the daily recurrence of the transport system, public or private, or the influx of vehicles, and a second phase of discharge and conversion of energy to generate electricity.

In the present invention, as active weight is understood as the one capable of moving from the end point of the process (level of greatest decrease), to the initial point (highest level, or of greater potential energy) using its own driving impulse, thus differentiating itself of the deadweight as the one that needs to reverse the process to return to the starting point through its trailer to provide itself with potential energy, resulting in a net loss of energy.

In addition, the fact of using an active weight makes it possible to dispense with supply electricity to operate at any stage of the process, unlike the systems known in the state of the art that required electricity to power a pump, or reversible turbine / pump, to raise the piston in order to recover potential energy.

On the other hand, the system of the invention makes it possible to extract more energy than the systems known in the prior art of a similar nature, which are based on a short or percussion piston, and at the same time allow the stored energy to be available, either to keep it as a reserve or to generate electricity immediately and continuously.

The applications of the system of the present invention can be all those in which there is daily recurrence of a means of transport upon arrival at a specific physical point, or also of large vehicular influx: the number of arrivals of a transport vehicle public (bus, tram, subway, train, etc.) to a station or garage, parking,

incorporation of vehicles by descending to a road or highway located at a

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lower level, cargo trucks, etc.

Advantageously, the system comprises two accumulator tanks connected in parallel to the set of cylinder-piston actuators, both tanks being provided to act by alternating the loading and unloading of fluid, so that when one of the tanks is discharging the accumulated fluid towards the turbine , the other tank is storing fluid inside, thus providing system operation without interruptions.

The two pressure accumulator tanks alternate in the loading and unloading, which is carried out continuously, so that their capacity is contained. For an energy reserve, for example for charging electric vehicles during the night, the capacity of the accumulator tanks will increase proportionally, either by increasing their volume, that is to say their diameter, so that it does not imply a pressure penalty, or by adding more accumulator tanks.

According to a first embodiment of the invention, the recovery tank and the turbine are arranged at a height higher than the level of the platform in its upper position. In this case, it is necessary to enable a construction for its confinement, such as a building.

According to a second embodiment of the invention, the recovery tank and the turbine are disposed underground below the level of the platform, either under its upper or lower position.

Additionally, in this second embodiment, the system comprises a pump coupled at an outlet of the recovery tank, capable of propelling the contained fluid towards the cylinder-piston actuator assembly to raise the empty platform to its upper position.

The advantage of the system of this second embodiment with respect to the first embodiment is that the hydraulic circuit is buried and therefore completely hidden. Although the feeding pump involves a consumption and consequent loss of electrical energy, the net energy balance is compensated by a direct generation of power that is greater than in the preceding case of the first embodiment, because the turbine is at

discharge level of the accumulator tank, and not at the highest level.

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Advantageously, the system valve assembly comprises an automatic shut-off valve downstream of the cylinder-piston actuator assembly capable of being opened to allow the passage of the driven fluid during the descent of the loaded platform with the active weight towards the respective accumulator tank ; a non-return valve at an inlet of the respective accumulator tank that prevents fluid from flowing back during and after fluid storage; an automatic shut-off valve at an outlet of the respective accumulator tank capable of being opened to allow the accumulated fluid in said accumulator tank to pass to the turbine; and an automatic shut-off valve downstream of said recovery tank capable of being opened to allow the passage of the stored fluid to the cylinder-piston actuator assembly to cause the ascent of the empty platform.

Optionally, the system comprises auxiliary thrusting means to raise the empty platform to its upper position, which can be activated when the pressure of the fluid discharged from the recovery tank to the cylinder-piston actuator assembly is not sufficient to overcome the back pressure exerted by the empty platform.

Preferably, the auxiliary thrust means comprise hydraulic actuation means provided with a piston connected to an outlet of a barrel containing a fluid pressed by a counterweight, the piston being coupled to a scissor mechanism which in turn is articulated to the platform, and an automatic shut-off valve disposed at the outlet of the barrel that regulates the passage of fluid to the piston to raise said scissor mechanism.

Although the auxiliary mechanism described is operated by a hydraulic type device, it should be noted that other devices, for example, mechanical type, could also be used.

Preferably, the system comprises an ascending ramp intended for the active weight to leave the system, whose trajectory communicates the level where the lower position of the platform is located with the level of the pavement where the upper position of the platform is located.

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In this way, the active weight will recover the potential energy transferred up the ramp. From the moment that the active weight has left the platform, the energy arranged to access the upper level, for example the street level, is foreign to the system.

According to another feature of the invention, the system comprises an active weight weighing device, provided with control means which, depending on the value of the recorded weight, allow one or more pistons to be selected from the set of actuators necessary to guarantee a sustained descent of the platform. loaded with said active weight and maximize the thrust generated regardless of the mass of the active weight.

Preferably, the weighing device is arranged in a position prior to the platform, so that the active weight is capable of being weighed before reaching said platform.

Advantageously, the platform comprises anchoring means provided to prevent its descent during the operation of loading the active weight on it.

According to another characteristic of the invention, the weight of the accumulator tank is of modular type capable of being mounted in situ, comprising a plurality of individual pieces stackable on a base intended to make contact with the accumulated fluid as a piston, the number being of individual parts to be mounted on the variable base depending on the weight required in the weight.

According to a variant, the base of the weight is configured by a hollow cylindrical body and the individual pieces have a configuration in the form of stackable discs within said hollow cylindrical body.

According to another variant, the base of the weight is configured by a solid cylindrical body and an intermediate support attachable on said body as a cap provided with a peripheral wing, and the individual pieces have a configuration in the form of stackable rings on said peripheral wing, the cross section of the set of ring-shaped parts being substantially larger than the cross section of the base, thus allowing the total height of the weight to be restricted without compromising its weight.

Preferably, each stackable ring-shaped piece is divided into a plurality of

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modules, said modules being coupled together to form a stackable piece and in turn coupled with the modules of the respective adjacent stackable pieces.

According to another characteristic of the invention, the cylinder-piston actuator is of the telescopic type, the cylinder comprising a plurality of longitudinal sections capable of being collected within the former. In this way, the height of the cylinder in the position of maximum descent of the piston is substantially equivalent to the height of the last section fitted.

Preferably, each of the telescopic sections has the same internal cross section, providing a constant thrust force along the piston stroke.

In accordance with another aspect, the invention also relates to a parking facility for land transport vehicles, comprising the potential energy storage and electric power generation system described above, in which the mobile platform is located in an area of entry of vehicles, said vehicles acting as active weight in the system before being parked.

Advantageously, the installation comprising the system of the invention can be a car park, or a station of a means of public transport of vehicles, such as train, subway, bus, or tram, among others.

Brief description of the drawings

The attached drawings illustrate, by way of non-limiting example, preferred embodiments of the potential energy storage and electric power generation system object of the invention. In these drawings:

Fig. 1 is a schematic view of the system according to a first embodiment with the recovery tank and the turbine arranged in an elevated position;

Figures 2a and 2b schematically show the actuation sequence of a conventional cylinder-piston actuator, showing the piston in the lower position and in the upper position, respectively;

Figure 3a is a schematic view of the platform with the active weight installed in a

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underground parking, showing an ascent ramp that connects the lower level of the platform with the upper level where the exit of the system is located; Figure 3b is a schematic view of the platform with the active weight installed in an elevated parking lot, showing an ascent ramp towards the upper level where the platform is located, the system exit being at the lower level of the platform; Figure 4 is a schematic view of the system showing the balance of pressures exerted on the fluid driven by the hydraulic actuators and on the fluid stored in the potential energy storage tank;

Figure 5a schematically shows an auxiliary hydraulic pushing device that drives a scissor type mechanism;

Figure 5b is a schematic perspective view of the scissor mechanism showing the two lower fluid delivery points for its elevation;

Figure 6 is a schematic view of the system according to a second embodiment with the recovery tank and the turbine arranged in an underground position; Figures 7a to 7e schematically show a sequence of the operation of the system before the active weight is placed on the platform to begin its descent; Figures 8a to 8c show respectively three cases of selection of the piston assembly for supporting the platform, as a function of the registered weight of the respective active weight;

Figures 9a and 9b schematically show an exploded and elevation view, respectively, of a weight of the accumulator tank according to a first variant; Figures 10a to 10c schematically show an exploded view, in cross-section and plan view, respectively, of a weight of the accumulator tank according to a second variant; Y

Figure 11 shows a cross section of a variant of the telescopic-type cylinder-piston actuator;

Detailed description of the drawings

A first embodiment of the potential energy storage and electric power generation system of the present invention is shown in Figure 1.

The system is configured by a hydraulic circuit comprising a mobile platform 1 capable of moving according to an alternative movement between an upper position A and a

lower position B, the platform 1 being supported by a set of actuators

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2 hydraulics provided with at least one piston cylinder whose cylinder chamber 3 contains a volume of hydraulic fluid 5, such as water or hydraulic oil, as can be seen in Figures 2a and 2b.

The platform 1 is configured to receive on its surface an active weight 6 with its own motor capacity whose impulse allows it to be positioned on the platform 1 in the upper position A and to leave said platform 1 in the lower position B.

In the present invention, active weight is understood as a mass, such as a land transport vehicle (automobile, train, subway, bus, tram, etc.), with its own driving capacity (internal combustion engine, traction mechanism, electric motor , etc.) capable of gaining potential energy by virtue of the impulse that intrinsically generates the driving system with which it is endowed, and which is in turn extrinsic to the object of the present invention, and equally residual, to the same extent that it is also the disruption it generates, and therefore not being accounted for in the global energy calculation.

In this way, the platform 1 loaded with the active weight 6 is able to descend by gravity in a sustained manner to the lower position B, in turn causing a pushing force on the actuator assembly 2.

The system also comprises at least one accumulator tank 7 of potential energy capable of storing the volume of fluid 5 driven by the set of actuators 2 during a predetermined number of descent cycles of the platform 1 loaded with the active weight 6.

The accumulator tank 7 is provided with a weight 8 arranged floating above the level of the stored fluid to exert a predetermined hydraulic pressure on the fluid. Said weight 8 is sized to conserve the pressure at which the fluid is injected, that is, its potential energy.

The operation of the system is therefore analogous to that of the hydraulic jack, which in turn is based on the Pascal principle and the complete transfer of pressure and volume of a fluid through communicating vessels, so that the resulting thrust force allows conserve the injected potential energy.

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Said accumulator tank 7 is capable of discharging the volume of stored fluid to a turbine 9, which in turn is connected to an electric generator 10 to produce electricity.

Depending on the magnitude of the available pressure at the inlet of turbine 9, the most suitable turbine typology for power generation will be determined. A higher injection pressure is generally desirable, which implies a greater weight 8 that retains said pressure.

Taking into account that the electricity demand is greater during the day, it is therefore desirable to generate electricity continuously through a repeated charge and discharge operation of the accumulator tank 7. A system with multiple accumulator tanks offers versatility, with reserves whose discharge It can be deferred based on specific needs, such as producing electricity for recharging batteries to electric vehicles during the night.

It is envisaged, in this example, the use of two 7.7 ’storage tanks of minimum capacity (volume) alternating in loading and unloading. The modular capacity of the system allows multiple combinations of loading and unloading (simultaneous or in sequence) that adapt to specific power delivery requirements. Thus, the system inherently stores energy as a previous step to the generation of electricity, requiring greater accumulation capacity (either in volume of the accumulator tank, or in the number of accumulator tanks) in case of energy reserve.

The two accumulator tanks 7.7 'are connected in parallel to the set of actuators 2 of the cylinder-piston, which are loaded and unloaded alternately and fed to a single turbine 9, thereby achieving that the loading and unloading can be carried out simultaneously, being able to accumulate energy and generate electricity in a continuous and uninterrupted way.

The system also comprises a set of valves actuated by means of control, as will be described below, and a recovery tank 11 provided for storing the fluid from the turbine 9 and recirculating it towards the set of actuators 2, the circuit being closed, so that said set of actuators 2 is

capable of exerting a pushing force on the empty platform 1, devoid of weight

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active, to drive it from the lower position B to the upper position A, thus being prepared to receive another active weight 6.

In this first embodiment shown in Figure 1, it can be seen that the recovery tank 11 and the turbine 9 are arranged at a height greater than the height of the platform 1 in its upper position A, for example at street level, by what is necessary to enable a construction for its confinement, such as a building.

Next, the operation of the system according to this first embodiment is described in more detail:

First, the active weight 6, in this case a passenger vehicle that arrives at a station, such as a car, subway, tram, train or passenger bus, rides on platform 1. Said platform 1 descends by force of thrust produced by its weight, that is, by gravity, transferring the volume of fluid 5 that displaces the cylinder-piston actuator 2 to one of the two accumulative tanks 7 of potential energy, each of which mounts a weight 8, whose function is to maintain the pressure of the injected liquid. A non-return valve 12 prevents fluid from the accumulator 7 from flowing back to platform 1 as the active weight 6 releases weight while leaving platform 1.

Both 7.7 'accumulators work by alternating the loading and unloading of fluid in an inverted manner; while one loads, the other downloads, and vice versa. For the injection or loading of the first accumulator 7, an automatic shut-off valve 13 that is disposed downstream of the cylinder-piston actuator 2 remains open and a valve 14 that is disposed at the outlet of the accumulator tank 7 is closed.

During successive descents of the cylinder-piston actuator 2, the accumulator tank 7 will be filled and causing the weight 8 to rise. At the same time, the second accumulator 7 'is discharged, which keeps the respective valve 13' closed. and the respective valve 14 'open. The complete discharge of the second accumulator 7 ’is a signal that activates the discharge of the first, reversing the operation by opening valves 14 and 13’, and closing valves 13 and 14 ’.

With the discharge the progressive descent of the weight 8 occurs, which displaces the fluid

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contained in the accumulator tank 7 through an ascending duct 15 that passes through the turbine 9 and moves the blades thereof to generate mechanical power, which is converted into electrical power by means of the electric generator 10 coupled to the turbine's arrow 9. From the turbine 9 the fluid discharges into the recovery tank 11. By opening an automatic valve 16 the fluid contained in said recovery tank 11 will feed the cylinder-piston actuator 2 by the force of gravity generated through the fluid column in line 17, which will raise said cylinder-piston actuator 2 and the platform 1 without load. Once the ascent is complete, the fluid will have completed the cycle.

In Figures 2a and 2b the basic sequence of a conventional cylinder-piston actuator 2, during the descent and ascent of the platform 1, respectively, is schematically represented.

During the descent, shown in Figure 2a, due to the pushing force of the active weight 6 that mounts the platform 1, the piston 4 will descend inside the cylinder 3 moving the fluid 5 inside it in the direction of the accumulator tank 7, the automatic shut-off valve 13 and the non-return valve 12 being open to facilitate said operation. On the other hand, the ascent of the platform, shown in Figure 2b, is carried out thanks to the discharge of the recovery tank 11, the automatic valve 16 being open and the automatic valve 13 closed. Thus, the liquid pressure displaces the piston 4, pushing the platform 1 up to its maximum ascent A position.

Referring now to Figure 3a, once the descent of the platform 1 to the lower level B is concluded, the active weight 6 will leave said platform 1 and recover height until reaching the original upper level A, in this example at the street level, ascending on a ramp 18 of progressive slope. In this way, the active weight 6 will recover the potential energy transferred up said ramp 18.

Alternatively, the active weight 6 could be incorporated into a road that runs at the lowered level B, so the use of a ramp would not be necessary. In this case, the active weight 6 itself can obtain a net energy gain in the form of fuel savings and less wear, due to the lower trajectory.

The system can be applied to a car park. In the case of underground parking

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(See figure 3a), the vehicle 6 will descend by platform 1 to the lowest level (position B), and to go outside it will climb the successive ramps 18 until reaching the street level (position A). In the case of an elevated parking lot (see figure 3b), the exit to the outside will be preceded by the ascent by the corresponding ramps 18 'to the highest floor (position A) and the descent by platform 1 to the street level (position B), being able to extend the descent if necessary to make the exit for a last ascent ramp (not shown). From the moment the vehicle has left platform 1, the energy available to access the street is foreign to the system.

In Figure 4 it can be seen that the thrust forces generated by the active weight 6 and the weight 8 of the accumulator tank 7 are balanced at the level (I) where the weight 8 is in contact with the fluid, whereby the capacity of Injection is maximum when the accumulator tank 7 is empty and the weight 8 has dropped completely, because the thrust due to the active weight 6 on the platform 1 will add the weight generated by the entire column until the entrance to the accumulator tank 7, that is : the stroke (II) of the piston 4, the clearance (III) between the level of descent of the platform 1 and the weight 8 of the accumulator tank 7 at its maximum ascent level, the height (IV) of the weight 8, and the height (V) occupied by the fluid with the accumulator tank 7 full. This last height (V) therefore generates a variable pressure component that opposes greater resistance to injection with height. Therefore, the design of the accumulator tank 7 will maintain a contained height, favoring an increase in diameter to expand its capacity.

Consequently, it is desirable to concentrate the pressure on the mass of the weight 8, and not on the fluid column, since the mass of the weight 8 is constant, and the column of the accumulated fluid in said accumulator tank 7 gradually decreases with download

Likewise, it is important to maintain a sustained descent of the platform 1, so it is necessary to control the injection rate, that is, the transfer rate of the volume of fluid 5 driven towards the accumulator tank 7.

It is known that the power generated depends on the characterization of the flow, which depends on two magnitudes: the pressure and the flow rate, the latter being the transfer speed of a volume of fluid. Optimize volume by increasing the characteristic diameter (already

either with a larger section of the piston, or with multiple pistons in parallel) occurs

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to the detriment of pressure, while the same force is distributed over a larger surface. Consequently, the increase in volume must occur by increasing the piston stroke, in order to maintain the pressure.

From which, it should be noted that the distance of descent has a power multiplier effect. Indeed, the increase in the piston stroke is proportional to the volume of fluid injection, as well as to the inclined distance of the ramp for the recovery of the level before the descent (upper position), and ultimately, to the mechanical power generated.

It should be noted that the operation of the system according to this first embodiment, with the recovery tank 11 raised, is conceptually free of electricity consumption, requiring it only for the control means and the operation of the automatic valves. To do this, the thrust of the weight 8 of the accumulator tank 7 must print enough pressure to transport the fluid content to the highest point of the circuit, which is where the hydraulic turbine 9 is located, and in additional mode generate power. The assembly of the platform 1 and the hydraulic actuators 2 can be lifted by gravity from the fluid in the recovery tank 11, which must have a sufficient column to compensate for the pressure exerted by the weight of the empty platform 1.

However, if the weight of the empty platform 1 generates a pressure of considerable magnitude, a thrust could be generated such that the fluid column from the recovery tank 11 could not compensate for gravity. Increasing said column would mean the displacement of the turbine 9 and the recovery tank 11 at a higher height, being able to be impracticable due to architectural or space restrictions, and also generating a greater back pressure in the discharge from the accumulator tank 7, which would penalize efficiency of the cycle The proposed solution is to attach an auxiliary device 19, which can be hydraulic or mechanical, in which the restitution of the height of the platform 1 is carried out by a counterweight, in a manner similar to that performed in electric elevators.

An example of massive weight can be the case in which on the platform of a meter,

In addition to the wagons, the passenger platform is mounted, whose weight is assumed to be high.

This allows the rise and fall of passengers to the wagons to occur

simultaneously with the descent of the platform, and thereby minimize disruption

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caused by the time in which the fluid injection into the accumulator tank 7 is performed.

An example of an auxiliary device 19 of the hydraulic type comprising a piston 20 connected to an outlet of a barrel 21 containing a fluid pressed by a counterweight 22 is shown in FIG. 5, the piston 20 being coupled to a scissor mechanism 23 which in turn is articulated to the platform 1, and an automatic shut-off valve 24 disposed at the outlet of the barrel 21 that regulates the passage of the fluid to the piston 20 to raise said scissor mechanism 23. In this case, the mechanism scissor 23 comprises two rolling ends, upper 25a and lower 25b, and two anchored but articulated ends, upper 25c and lower 25d.

As can be seen in Figure 5b, the same piston 20 can feed the same line that simultaneously feeds two lower points 25b of the lower rolling end of said scissor mechanism 23.

The valve 24 opens to allow the passage of the fluid that moves the piston 20 to one side or the other. During the injection, the thrust of the platform 1 in its descent with the active weight 6 mounted moves the counterweight 22 upwards, closing after which the valve 24. At the moment of raising the platform 1, the valve 24 reopens. The counterweight 22 produces a thrust that is greater than the weight of the empty platform 1 and the piston 20.

Although the auxiliary mechanism 19 described is actuated by a hydraulic type device, it should be noted that other devices, for example, mechanical type, could also be used.

A second embodiment of the system of the invention is schematically shown in Figure 6, in which it can be seen that the recovery tank 11 and the turbine 9 are arranged buried below the level of the platform 1 in its upper position A (level of street), which allows to have a hidden installation.

The system comprises the same components as those described in the first embodiment, using the same numerical references, with the difference that it also comprises a feed pump 26 coupled to an outlet of the recovery tank 11,

capable of propelling the contained fluid towards the set of actuators 2 of cylinder-piston

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to raise the empty platform 1 to its upper position A. In this case, the turbine 9 generates a greater power because, being free of the ascending duct 15 (see figure 1), it has the fluid at a higher pressure.

The advantage of the system of this second embodiment with respect to the first embodiment is that, as mentioned, the hydraulic circuit is buried and therefore completely hidden. Although the feed pump 26 involves a consumption and consequent loss of electrical energy, the net energy balance is compensated by a direct generation of power that is greater than in the preceding case of the first embodiment, because the turbine 9 is at discharge level of accumulator tank 7, and not at the highest level.

Similarly, in case of having a massive weight that prevents the pump 26 from lifting the empty platform 1, an auxiliary lifting device 19 can be used, as described in the first embodiment.

On the other hand, another aspect to take into account is the fact that the active weight 6 can vary significantly depending on the type of vehicle and the number of passengers it incorporates, which influences the thrust force transferred to the set of actuators 2 Hydraulic To optimize the injection of fluid 5, so as to result in a greater potential transfer energy, the system of the invention allows the geometry of the hydraulic actuator assembly 2 to be adjusted based on the net weight of each active weight 6, as will be described continuation.

Figures 7a to 7e sequentially describe the process of optimizing fluid injection 5, the system being applied in this example to a car park.

For this, the system comprises a weighing device 27 of the active weight 6, provided with control means which, depending on the value of the registered weight, allow one or more pistons 4 to be selected from the set of actuators 2 necessary to support the platform 1 loaded with said weight. 6 active weight so that a sustained descent is guaranteed. In this example, the weighing device used is a conventional axial scale 27, arranged in a position prior to platform 1, so that the active weight 6 is capable of being weighed before reaching said platform 1.

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In Figure 7a, it can be seen how the vehicle 6 is about to pass the axles of the wheels over the axial scale 27 that calculates the net weight of the vehicle 6.

In figure 7b, the vehicle 6 has exceeded the axial scale 27, whereby the value of the registered weight is entered in its automatic control system, whose central management system, by means of an algorithm with a preset pressure value adjusts the geometry injection depending on weight. Likewise, a barrier 28 is used to indicate to the vehicle 6 that it cannot yet be mounted on the platform 1.

In figure 7c, it is shown how the control system acts on the valve 16, which in this case feeds the central piston 4 which in turn lifts the platform 1. The valve 16 'that feeds the rest of the pistons 4' is keep closed. Also, a mechanical device provided with anchoring means 29 retains the platform 1, preventing it from descending at the time of mounting the vehicle 6 on it.

The opening of the valve 16 allows the recovery tank 11 to be discharged towards the selected piston 4, either by the action of gravity according to the first embodiment (see figure 1) or by starting the pump 26 according to the second embodiment ( see figure 6), allowing platform 1 to be lifted. With the ascent completed, all valves are kept closed, and if necessary, pump 26 is turned off.

Next, as can be seen in Figure 7d, the barrier 28 opens allowing the driver to position his vehicle 6 on the descent platform 1, as finally shown in Figure 7e.

In Figures 8a to 8c, a bottom plan view of the platform 1 is schematically illustrated, showing in dark color those pistons 4,4 ', 4' 'selected according to the weight of the vehicle 6, so that at a higher weight of the vehicle 6 greater injection area will be necessary to optimize the thrust force versus area ratio within the design pressure range that maintains the thrust of the weight 8 of the accumulator tank 7. Also, the distribution of the pistons is carried out in a manner equitable on the surface of platform 1.

Figure 8a shows the case of a vehicle weight 6 located in the lower range, in which

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a single piston 4 of greater section has been selected which is located in the central part of the platform 1; Figure 8b shows the case of a vehicle weight 6 located in an intermediate range in which two other pistons 4 ’have been activated in addition to the central piston 4; and Figure 8c shows the case of a vehicle weight located in a greater range in which four different 4 ’pistons have been activated in addition to the central piston 4.

On the other hand, another aspect to consider is the configuration of the weight 8 of the accumulator tank 7, said weight 8 being able to be modular in order to facilitate its transport and assembly on site.

In figures 9a and 9b a first variant of a weight 8 is shown comprising a plurality of individual pieces 30 in the form of stackable discs on a base 31 configured by a hollow cylindrical body, said base 31 being intended to exert contact with the accumulated fluid as a piston. The base 31 further comprises a central bar intended to keep the disks stacked, thereby restricting their displacement horizontally. The number of individual pieces 30 to be mounted on the base 31 is variable depending on the weight required in the weight 8.

In Figures 10a to 10c a second variant of a weight 8a can be seen, whose base 31 is configured by a solid cylindrical body 32 acting as a piston, and an intermediate support attachable on said body 32 as a cap 33 provided of a peripheral wing 33a. In this example, as shown in Figure 10a, the solid body 32 is sectioned with disks stacked and held together in a manner similar to that shown in Figure 9a of the first variant. The height of the solid body 32 must be greater than the height (h) of the accumulator tank 7 to provide a distance (d) for the insertion of the cap 33.

In this case, the individual pieces 30 have a configuration in the form of stackable rings on said peripheral wing 33a of the cap 33. The cross-section of the set of ring-shaped pieces 30 is substantially larger than the cross-section of the base 31. This configuration allows restricting the total height of the weight 8a without reducing its weight, preferably using materials such as high density concrete that provide optimum compaction. However, the cap 33 could be a casting, due to the greater tensile strength, typical of the metal, with respect to the

concrete, although depending on the weight of the individual pieces 30 the use of concrete

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It could be enough.

Likewise, each individual piece 30 stackable in the form of a ring is divided into a plurality of modules 30a, said modules 30a being coupled to each other by means of first engagement elements 34 with complementary shape to form an individual piece 30, and in turn coupled with the modules 30a of the respective individual pieces 30 adjacent stackable by means of similar second fitting elements 35. In figure 10c one of said modules 30a is shown in part showing said fitting elements 34,35.

On the other hand, another variant of the cylinder-piston actuator 2a is shown in Figure 11, which is of the telescopic type. In this case, the cylinder 3 comprises a plurality of longitudinal sections 3a, 3b, 3c capable of being collected within the former. This alternative with the telescopic cylinder is more efficient, from the point of view of space, for its construction and structural rigidity. It also allows a greater vertical ascent / descent distance compared to the conventional model.

When all sections 3a, 3b, 3c, which are stacked in one, are retracted, the total height of the cylinder 3 in the position of maximum descent of the piston 4 is substantially equivalent to the height of the last fitted section 3c. This saves vertical digging distance to accommodate the cylinder housing 3.

Also, each of the telescopic sections 3a, 3b, 3c have the same internal cross-section, so that the thrust force of the piston 4 remains constant throughout its stroke. In addition, sections 3a, 3b, 3c have bearings 3 ’on their outer wall that allow linear displacement, and in the upper part they have the function of retaining the liquid, preventing its escape to the outside.

Claims (21)

5 10 fifteen twenty 25 30 35 1. Potential energy storage and electric power generation system, configured by a hydraulic circuit comprising at least one mobile platform (1) capable of moving according to an alternative movement between an upper position (A) and a lower position (B) , the platform (1) being supported by a set of hydraulic actuators (2) provided with at least one piston cylinder whose cylinder chamber (3) contains a volume of hydraulic fluid (5), and the platform (1) being configured to receive on its surface an active weight (6), meaning active weight (6) a mass with its own motor capacity whose impulse allows it to be positioned on the platform (1) in the upper position (A) and to leave said platform ( 1) in the lower position (B), so that the platform (1) loaded with the active weight (6) is able to descend by gravity in a sustained way to the lower position (B), causing in turn, a pushing force on the actuator assembly (2), characterized in that the system comprises at least one accumulator tank (7) of potential energy capable of storing the volume of fluid (5) driven by the actuator assembly (2) during a predetermined number of platform descent cycles (I) loaded with the active weight (6), said accumulator tank (7) being provided with a weight (8) arranged floating above the level of the stored fluid to exert a predetermined hydraulic pressure, and said accumulator tank (7) being capable of discharging the volume of stored fluid to a turbine (9), which in turn is connected to an electric generator (10) to produce electricity; a set of valves (12,13,14,16) actuated by means of control; and a recovery deposit (II) intended to store the fluid from the turbine (9) and recirculate it towards the actuator assembly (2), the circuit being closed, so that said actuator assembly (2) is capable of exerting a pushing force on the empty platform (1), devoid of the active weight (6), to drive it from the lower position (B) to the upper position (A), thus being prepared to receive another active weight (6). 2. System according to claim 1, characterized in that it comprises two accumulator tanks (7.7 ') connected in parallel to the set of actuators (2) of cylinder-piston, both tanks (7.7') being provided to act by alternating the loading and unloading of fluid, so that when one of the tanks (7) is discharging the accumulated fluid to the turbine (9), the other tank (7 ') is storing fluid inside. 5 10 fifteen twenty 25 30 35 3. System according to claim 1 or 2, characterized in that the deposit of recovery (11) and the turbine (9) are arranged at a height higher than the level of the platform (1) in its upper position (A). 4. System according to claim 1 or 2, characterized in that the deposit of recovery (11) and the turbine (9) are arranged buried below the level of the platform (1), either under its upper (A) or lower (B) position. System according to claim 4, characterized in that it further comprises a pump (26) coupled to an outlet of the recovery tank (11), capable of driving the contained fluid towards the set of actuators (2) of cylinder-piston to raise the platform (1) empties to its upper position (A). 6. System, according to any of the preceding claims, characterized in that the valve assembly comprises an automatic shut-off valve (13) downstream of the cylinder-piston actuator assembly (2) capable of opening to allow the passage of fluid (5). ) driven during the descent of the platform (1) loaded with the active weight (6) towards the respective accumulator tank (7); a non-return valve (12) at an inlet of the respective accumulator tank (7) that prevents fluid from flowing back during and after fluid storage; an automatic shut-off valve (14) at an outlet of the respective accumulator tank (7) capable of opening to allow the accumulated fluid in said accumulator tank (7) to pass through the turbine (9); and an automatic shut-off valve (16) downstream of said recovery tank capable of being opened to allow the passage of the stored fluid towards the set of cylinder-piston actuators (2) to produce the ascent of the empty platform (1). System according to any of the preceding claims, characterized in that it comprises auxiliary means (19) for pushing the empty platform (1) to its upper position (A), which can be activated when the pressure of the fluid discharged from the recovery tank (11) towards the set of actuators (2) of cylinder-piston is not sufficient to overcome the back pressure exerted by the empty platform (1). System according to claim 7, characterized in that the auxiliary thrusting means (19) comprise hydraulic actuation means provided with a piston (20) connected to an outlet of a barrel (21) containing a fluid pressed by a 5 10 fifteen twenty 25 30 35 counterweight (22), the piston (20) being coupled to a scissor mechanism (23) which in turn is articulated to the platform (1), and an automatic shut-off valve (24) disposed at the barrel outlet (21 ) which regulates the passage of fluid to the piston (20) to raise said scissor mechanism (23). 9. System, according to any of the preceding claims, characterized in that it comprises an ascending ramp (18) provided for the active weight (6) to leave the system, whose trajectory communicates the level where the lower position (B) of the platform is located (1) with the level of the pavement where the upper position (A) of the platform (1) is located. 10. System, according to any of the preceding claims, characterized in that it comprises a weighing device (27) of the active weight (6), provided with control means which, depending on the value of the recorded weight, allow one or more pistons (4, 4 ', 4' ') of the set of actuators (2) necessary to ensure a sustained descent of the platform (1) loaded with said active weight (6) and maximize the thrust generated independently of the mass of the active weight (6). A system according to claim 10, characterized in that the weighing device (27) is arranged in a position prior to the platform (1), so that the active weight (6) is capable of being weighed before reaching said platform (one). 12. System, according to any of the preceding claims, characterized in that the platform (1) comprises anchoring means (29) provided to prevent its descent during the loading operation of the active weight (6) thereon. 13. System according to any of the preceding claims, characterized in that the weight (8,8a) of the accumulator tank (7) is of modular type capable of being mounted in situ, comprising a plurality of individual pieces (30) stackable on a base (31) intended to make contact with the accumulated fluid as a piston, the number of individual parts (30) to be mounted on the base (31) variable depending on the weight required in the weight (8.8a). 14. System according to claim 13, characterized in that the base (31) of the weight (8) is configured by a hollow cylindrical body and because the individual parts (30) have a configuration in the form of stackable discs within said cylindrical body hole. 5 10 fifteen twenty 25 30 15. System according to claim 13, characterized in that the base (31) of the weight (8a) is configured by a solid cylindrical body (32) and an intermediate support attachable on said body as a cap (32) provided with a peripheral wing (32a), and because the individual pieces (30) have a configuration in the form of stackable rings on said peripheral wing (32a), the cross-section of the set of pieces (30) being in the form of a ring substantially larger than the section transverse base (31). 16. System according to claim 15, characterized in that each stackable piece (30) in the form of a ring is divided into a plurality of modules (30a), said modules (30a) being coupled together to form a stackable piece (30) already in turn, coupled with the modules (30a) of the respective adjacent stackable parts (30). 17. System according to any one of the preceding claims, characterized in that the cylinder-piston actuator (2a) is of the telescopic type, the cylinder (3) comprising a plurality of longitudinal sections (3a, 3b, 3c) capable of being collected within from the previous one. 18. System according to claim 17, characterized in that each of the telescopic sections (3a, 3b, 3c) have the same internal cross-section, providing a constant thrust force along the piston stroke (4). 19. Parking installation for land transport vehicles, comprising the potential energy storage and electric power generation system, according to any of the preceding claims, wherein the mobile platform (1) is located in an entrance area of vehicles, said vehicles acting as active weight (6) in the system before being parked. 20. Installation according to claim 19, characterized in that it is a car park. 21. Installation according to claim 19, characterized in that it is a station of a means of public transport of vehicles.