EP3184807B1 - System for energy storage and recovery - Google Patents

Description

The invention relates to a system for energy storage and recovery according to the features of patent claim 1.

New developments in the field of alternative energies, in particular those of discontinuous processes, such as solar or wind energy, have led to the situation that on the one hand operating times are given, in which the energy generated in some cases significantly exceeds the present demand, on the other hand, those in which it at the required and requested energy completely or at least partially missing. These fluctuations have made the need for suitable storage facilities for excess energy acute.

Thus, the development efforts are directed specifically to processes in which the electrical energy can first be converted into another energy source and recovered from this again.

One of these processes is hydrolysis, in which water and its components oxygen and hydrogen are recovered. Because of the difficulty of dealing with chemically active hydrogen, these processes, which generally also require a great deal of process engineering, are not available for widespread use in electrical energy storage and recovery.

The storage of electrical energy in electrical form has hitherto only been possible in accumulators in which a transition from electrical to chemical processes is brought about. However, it has not yet been possible to create devices in which the storage volume is high and the construction volume is low. For the storage of large amounts of energy or decentralized numerous arrangements of storage units such devices therefore do not form a suitable solution.

Other methods are directed to first use the resulting electrical energy to perform work, are filled with which memory, and perform the recovery also on the intermediate process of Arbeitsverrichtung. Such processes are eg in pumped storage power plants, dams, hydropneumatisehe Storage power plants, which are housed in disused caverns or mines used. The storage is done partly with compressed air or natural gas or in combination with water, which is injected into the gases for cooling.

The currently available energy stores are far from sufficient to store the fluctuations caused by renewable energy producers. At the same time the classic energy storage such as pumped storage power plant or dams are not enough and are difficult to realize for environmental reasons.

A process in which air is compressed and reused in compressed or compressed air engines to recover energy is described in US Pat DE 27 17 679 A , A disadvantage of such a method is the fact that air as an energy source for work machines has a relatively low efficiency and only effective if it can be enforced in high quantities, but which can hardly be produced in the given conditions of energy storage conditions.

Another method shows the WO 2006/084748 A1 , In this case, deformable or compressible parts in water tanks are pressurized and deformed. If energy is required, the water is removed, which is under pressure and thereby can drive devices. A disadvantage of this design is that the pressure on the consuming devices with the water pressure in the memory does not decrease linearly and that combines with the design of a very high cost.

Another storage method shows the DE601 18 987 T2 , This method is suitable for small storage such as on vehicles. For storage power plants which require a large storage volume, the method is not applicable.

Out DE 102011082726 A1 Constructions for memory are known. For the construction of storage power plants, these accumulators can not be used due to the complex construction and the low storage volume.

Out DE 10 2013 112 196 A1 is known a compressed air storage power plant. Compressed air storage power plants have poor efficiencies due to the physical conditions. The compression of a gas such as air is always associated with large heat developments. During the relaxation then again cold arises saved or recovered. The described combination between compressed air reservoir and pressurized water storage shows a practical way. In the described method, however, the compressed air is released before re-filling the water reservoir and re-pressurized with fresh compressed air. This requires a lot of energy to compress the compressed air with a poor efficiency.

US 2012/0279209 A1 describes an apparatus operating under atmospheric conditions to deliver a gas into a pressure-resistant container under high pressure and then gradually let it act on liquids in closed hydraulic apparatus until it is depressurized to atmospheric pressure. Disadvantage is in this process that to a necessary constant repetition again considerable energy expenditure for the compression of the gas and the operation of the hydraulic equipment is required.

Out DE 102013018741 A1 a system for energy storage and recovery is known in which excess energy is stored in a power network by means of compressed air in a compressed air tank. The energy recovery is accomplished by passing the compressed air into a water tank, which directs the water through a turbine and relaxes it. The generator driven by the turbine generates electricity, which is supplied to a power grid.

Out WO 2011/101647 A2 A system is known for storing and recovering energy with compressed air and pressurized water tanks, and a Pelton turbine and a power generation generator connected thereto.

Out FR 3 012 537 A1 and EP 0 230 636 A1 is the use of a Pelton turbine with a frequency converter known. The object of the invention is to provide a system for energy storage and energy recovery, which stores with high efficiency in an efficient manner excess energy in a public or non-public power grid and can be returned to selbiges same energy demand.

This object is achieved with the systems according to the features of independent claim 1. Advantageous embodiments of the invention are the subject of dependent claims.

The energy storage and recovery system according to the invention, in particular a power plant, comprises at least one compressed air tank, at least one pressurized water tank connected to the compressed air tank, at least one turbine operatively connected to the at least one pressurized water container, and a generator for generating electrical energy, a high-pressure pump for conveying water from a water reservoir into the pressurized water container. According to the invention, the turbine in operative connection with the at least one pressurized water tank is an overpressure turbine which is connected in series with a constant pressure turbine such that a drive shaft of the overpressure turbine is connected to a drive shaft of the constant pressure turbine and a drive shaft of the generator. The constant pressure turbine is arranged according to the invention between the positive pressure turbine and the generator, wherein the generator has an interface for connection to a public power grid.

The term "active connection" is understood below to mean that the pressurized water container is connected directly to the turbine. This means that the water flowing out of the pressurized water container is conducted directly to the turbine and drives it. The standing in operative connection with the pressurized water tank turbine is therefore not just driven by another turbine. In other words, the overpressure turbine is in operative connection with the pressurized water container and is driven by the outflowing water. In contrast, the constant-pressure turbine is driven by the water flowing out of the overpressure turbine.

With the system according to the invention an efficiency of more than 75%, in particular more than 85% is achieved. These efficiencies can be achieved in particular with outputs of more than 80 MW.

Since the overpressure turbine, eg Francis turbine and the constant pressure turbine, eg Pelton turbine are connected via their drive shafts with the generator, a constant balance between the pressure turbine and the constant pressure turbine arises in such a way that the decreasing by the current pressure reduction performance of the pressure turbine is balanced by the constant pressure turbine , Thus, the energy stored in the pressure vessels can be optimally converted by the generator into electrical energy. The pressure reduction at the entrance of the overpressure turbine is due to the falling pressure in the pressure water tank when water is removed from the pressurized water tank for power generation.

The drive shaft of the positive pressure turbine and the drive shaft of the constant pressure turbine can form a common shaft. Or the drive shaft of the overpressure turbine and the drive shaft of the constant pressure turbine can be connected to each other via a torsionally rigid coupling. Or the drive shaft of the overpressure turbine can be connected to the drive shaft of the constant pressure turbine via a transmission. It is also possible that an automatic clutch for decoupling the overpressure turbine is provided between the overpressure turbine and the constant pressure turbine.

Suitably, an outlet of the at least one pressurized water container is connected to an inlet of the overpressure turbine and an outlet of the overpressure turbine is connected to an inlet of the equi-pressure turbine. This ensures that the stored energy in the pressurized water can be obtained in two steps, namely in a first step, by the water is passed through the pressure turbine and in a subsequent step, that the water passed after flowing through the pressure turbine through the constant pressure turbine becomes.

By means of the tail of the pressure turbine, the discharge pressure from the pressure turbine can be controlled so that despite variable system pressure in the pressure water tank and thus variable input pressure of the pressure turbine, the discharge pressure from the pressure turbine and thus the inlet pressure in the constant pressure turbine can be kept constant. The capacity of the constant pressure turbine can be adjusted to the required generator power via adjustable inlet nozzles (tail unit). By controlling the constant pressure turbine by means of inlet nozzles (tail), the volume of water is adapted to the required power and thus the performance of the overpressure turbine by adjusting the tail unit indirectly adjusted to the overall performance of the turbine combination. It is expediently arranged between an outlet of the overpressure turbine and an inlet of the constant pressure turbine, a device for pressure regulation of the admission pressure of the constant pressure turbine.

The overpressure turbine is expediently designed for inlet pressures between 10 and 1000 bar, in particular between 225 bar and 500 bar.

With the system according to the invention investment costs can be reduced and an efficiency of up to 95% can be achieved.

In the case of several pressurized water containers, a connecting line may be present which connects the outlets of the pressurized water containers to one another, wherein the pressurized water containers are arranged relative to one another such that the connecting line enters Has slope and is connected at its lowest point (eg collector, water lock) with the inlet of the turbine (eg dip tube).

Exactly one pressure line can be present between an outlet of a compressed air tank and an inlet of a pressurized water tank, which is designed to conduct compressed air from the pressurized water tank to the compressed air tank and energy recovery compressed air from the compressed air tank to the pressurized water tank at energy storage. The line is dimensioned so that when bursting a compressed air tank only a small volume can flow out and thus only a small supply of compressed air is necessary. In the connecting line between the compressed air tank and the pressurized water container, a shut-off device may be arranged which is set to close the connection line in the event of a sudden drop in pressure. This ensures that not all the stored compressed air can escape when bursting a compressed air tank or a pressurized water tank.

In a plurality of compressed air tanks, a connection line may be present, which connects the outlet of several compressed air tanks together, wherein the plurality of compressed air tanks are arranged to each other such that the connecting line has a slope and is connected at its lowest point to an inlet of a pressurized water tank. This ensures that condensate formed in the compressed air tanks flows through the connecting line into the pressurized water tank. It is thus possible that several compressed air tanks are assigned to a single pressurized water tank. If the system also includes several pressurized water containers, this ensures that when a compressed air and / or pressurized water container bursts, not all the pressure volume stored in the system can escape. In other words, in this embodiment, the system according to the invention comprises a plurality of groups of pressure vessels, each group consisting of a plurality of compressed air tanks and a pressurized water tank. In the case of a malfunction of a group, the system can continue to access the other groups by separating the affected groups by means of a gate valve.

The compressed air tank and the pressure water tank are connected to each other so that a constant pressure equalization between the two containers takes place, so that during the energy storage as well as during the energy production of the pressure in the two containers is always balanced, ie between the pressurized water tank and the compressed air tank is a pressure equilibrium. This means that when energy storage, ie water is introduced into the pressure water tank, the pressure in the total volume of the pressurized water container always increases, on the other hand, the pressure in the total volume of the pressurized water tank is always identical to the pressure in the compressed air tank. In the energy recovery, ie water is led out of the pressurized water tank, the pressure in the total volume of the pressurized water tank always decreases on the one hand, on the other hand, the pressure in the total volume of the pressurized water tank is always identical to the pressure in the compressed air tank. In particular, a compressed air tank and a pressure water tank is connected via exactly one pressure line, which is designed to direct compressed air from the pressurized water tank to the compressed air tank and energy recovery compressed air from the compressed air tank to the pressurized water tank at energy storage. This pressure line is used in the energy recovery that compressed air from the compressed air tank can flow without pressure loss in the pressure water tank. When storing energy, this pressure line is used to allow compressed air from the pressurized water tank to flow into the compressed air tank without loss of pressure. This ensures a simple construction.

Between the compressed air tank and the pressurized water tank can be arranged, in particular in the connection line between the compressed air tank and the pressurized water tank, a compressed air turbine. As a result, additional energy can be obtained when flowing through compressed air through the connecting line, whereby the efficiency of the system according to the invention can be improved and increased

From the known prior art it is not known that during operation of the energy storage or recovery a pressure equilibrium between compressed air tank and pressurized water tank is present.

It should be further clarified that the proposed systems are used for energy storage as well as for energy recovery. Of course, the proposed systems for this purpose each have an operating state, namely a first state for energy storage and a second state for energy recovery.

In the energy storage, as will be described later, water is pumped via a high-pressure pump from a water reservoir into the pressurized water tank, wherein the high-pressure pump is operated by means of excess energy from a public or non-public power grid. Due to the increasing amount of water in the pressurized water tank, the remaining compressed air in the pressurized water tank is displaced into the connected compressed air tank with simultaneous pressure increase due to the constant volume of the tank. Due to the pressure balance between the pressurized water tank and the compressed air tank, there is always identical pressure in both tanks. This pressure increases continuously with increasing amount of water in the pressurized water tank up to a predetermined maximum value.

During energy recovery, water is supplied from the pressurized water tank to the Pelton turbine or the overpressure turbine and to the constant pressure turbine connected to it. A generator, which is connected to the drive shaft of the Pelton turbine or to the common drive shaft of the positive pressure turbine and constant pressure turbine generates energy which is supplied to a connected public or non-public power grid. Due to the decreasing amount of water at a constant volume of the container, the pressure in the pressurized water tank decreases. Due to the equalization of pressure between the pressurized water tank and the compressed air tank, both tanks have identical pressure at all times. This pressure decreases with decreasing amount of water in the pressure water tank and in the compressed air tank continuously up to a predetermined minimum value.

The proposed system works with operating pressures up to 500 bar. With appropriate design of the pressure vessel (pressurized water tank, compressed air tank) even pressures up to 1000 bar are possible. As a result, a high energy density is achieved, which can be stored in the smallest space. In this way, for example, powers between 2 and 450 MW are possible. By enlargement, ie enlargement of the compressed air tank and pressurized water tank any amount of energy can be stored much cheaper than previously known storage systems. For example, it is possible that the volume ratio between pressurized water tank and compressed air tank is 1: 1, 1: 2, 1: 3 or 1: 4 and more.

The proposed system essentially works with circulating water, which is expanded by the Pelton turbine or by the serial arrangement of the overpressure turbine and constant pressure turbine and pumped back by means of high-pressure pumps in the pressure water tank. The system works with a small amount of supplementary air. Supplementary air may be required due to leaks in the pressure system and can be topped up in the respective containers if necessary. The required amount is determined during operation of the proposed system via the control unit and supplied via a compressed air reservoir.

It may be provided for comparing the instantaneous pressure in the pressure water tank and / or the instantaneous pressure in the compressed air tank and the instantaneous amount of water in the pressure water tank with a target pressure value, a comparison device. The comparison device is designed such that, depending on the result of the comparison, compressed air is supplied to compressed air from a compressed air reservoir (air chamber). The leaked by leakage air is thus compensated by supplementary air. In particular, the compressed air reservoir is connected to a compressor for conveying outside air into the compressed air reservoir. In other words, the compressed air tank is filled exclusively with compressed air via an upstream compressed air reservoir, which can be filled by a compressor.

With the help of the compressor, the pressure is compressed once in the compressed air tank and pressurized water tank before commissioning of the storage power plant depending on the design to a pressure of 50, 100, 200 or up to 1000 bar. After startup of the system, i. during the operating phase, in which the system is used as a power plant for energy storage and energy recovery, the compressor is used exclusively for the supply of compressed air in a compressed air storage, which is upstream of the compressed air tank and only serves to replace the air leakage. The storage power plant can thus be operated at pressures of 50, 100, 200 or up to 1000 bar.

There may be a control unit, which is designed to control the high-pressure pump by means of electricity from the public power grid, depending on the utilization of a connected to the system or connectable public or non-public power grid to water from a water reservoir in the pressurized water tank to pump if there is an energy surplus in the public power grid. Pressurized water is passed from the pressurized water tank to the turbine and the power generated in the generator connected to the turbine is supplied to the public power grid when there is an energy demand in the public power grid. The proposed system can be stored with short reaction times either excess energy or stored energy can be made available.

The energy storage takes place without exception by recycling the circulation water with high-pressure pumps in the pressurized water tank. This process takes place only with excess energy from the public grid. The required compressed air is also generated only with excess energy from the public grid. The system according to the invention can be raised from 0 to 100% in about 65 seconds. Load changes occur in seconds. The high-pressure pumps can be designed so that they can be driven out of the stillsands to 100% power for about 25 seconds. The volume of the compressed air tank and the pressurized water tank can be designed so that the system of the invention over a period of up to 4 h can deliver the full design performance.

In this regard, it is proposed that the control unit is designed, in the case of energy recovery, to regulate the power generated by the overpressure turbine and / or the constant pressure turbine by opening or closing tail units (water inlet nozzles) connected to the overpressure turbine and / or the constant pressure turbine.

Advantage of the proposed systems is that it takes only a small space requirement and can be set up at any point in the vicinity of power lines, wind farms, Solaranalgen or large consumers. Furthermore, the proposed system does not require additional resources. For reasons of safety, it should be noted here that the storage system according to the invention, in particular the pressure vessels, is expediently installed underground. In particular, the system according to the invention can be constructed on flat or sloping terrain, in the smallest space. After the compressed air and pressurized water containers have been let into the earth, they are covered and reused as green space or arable land. Thus, the environment is minimally burdened and resources compared to conventional systems considerably spared. By housing the water reservoir to accommodate the relaxed from the turbine system water under the building to accommodate the turbines no additional space is needed for this. At the same time, the system is protected against contamination.

Fig. 1

die Anordnung einer Überdruckturbine und einer Gleichdruckturbine in einem erfindungsgemäßen System zur Energiespeicherung- und rückgewinnung,

Fig. 2

ein erfindungsgemäßes System zur Energiespeicherung- und rückgewinnung mit einer Kombination aus Überdruckturbine und Gleichdruckturbine und beispielhaft vier Druckluftbehältern und vier Druckwasserbehältern,

Fig. 3

ein erfindungsgemäßes System zur Energiespeicherung- und rückgewinnung. mit beispielhaft zwei Gruppen bestehend jeweils aus zwei Druckluftbehältern und einem Druckwasserbehälter

The invention and further advantages of the invention will be explained in more detail with reference to figures. Show it

Fig. 1

the arrangement of an overpressure turbine and a constant pressure turbine in an energy storage and recovery system according to the invention,

Fig. 2

an energy storage and recovery system according to the invention with a combination of overpressure turbine and constant pressure turbine and, by way of example, four compressed air tanks and four pressurized water tanks,

Fig. 3

an inventive system for energy storage and recovery. by way of example two groups each consisting of two compressed air tanks and a pressurized water tank

Fig. 1 shows the inventive arrangement of a positive pressure turbine 3 and a constant pressure turbine 3a in a system according to the invention for energy storage and recovery. Fig.1 does not show the other components of the system according to the invention for energy storage and recovery for the sake of simplicity and for better illustration. It will be on the Fig. 2 and 3 directed.

The overpressure turbine 3, eg,. a Francis turbine has an inlet E3 and an outlet A3. The inlet E3 is connected via a pressure line 5 with the / not shown pressurized water containers. The outlet A3 of the overpressure turbine 3 is connected to the inlet of a constant pressure turbine 3a, for example a Pelton turbine. The outlet (not shown) of the constant pressure turbine 3a is connected to a water reservoir for storing and collecting the water.

The drive shaft AW of the overpressure turbine 3 is connected to the drive shaft AW of the constant pressure turbine 3a. On the drive shaft AW, a generator 4 for generating electrical energy is also connected. The drive shaft AW is guided substantially centrally through the constant pressure turbine 3a. In particular, the drive shaft AW is a one-piece drive shaft AW.

Arrows indicate the direction of flow of the water through the pressure line 5 to the inlet E3 of the overpressure turbine 3, between the overpressure turbine 3 and the constant pressure turbine 3a.

Fig. 2 shows an inventive system for energy storage and recovery with a combination of pressure turbine and constant pressure turbine and exemplified four compressed air tanks 1 and four pressurized water tanks 2. Each pressure vessel 1, 2 is suitably designed as a single-walled container. Each container 1, 2 may have a volume of up to 300,000 m ³ and be designed for a pressure of up to 1000 bar.

Each compressed air tank 1 has an inlet 1e for compressed air and an outlet 1a for compressed air. The inlet 1e of a compressed air tank 1 is in communication with a compressed air reservoir 18, which also assumes the function of a compressed air equalizing tank. This compressed air reservoir 18 is connected to a compressor 17, which can supply compressed outside air to the compressed air reservoir 18. The power supply of the compressor 17 is effected by a system connected to the power grid or S. The refilling of compressed air from the compressed air reservoir 18 in a compressed air tank 1, as explained below, according to demand by a control and comparison unit 13th

The control and comparison unit 13 is connected via a data line 16 to a control valve 19. This control valve 19 is disposed between the compressed air reservoir 18 and the compressed air tank 1, in particular between the output of the compressed air reservoir 18 and the input 1e of a compressed air tank 1. Fig. 2 shows a single control valve 19, which is arranged in front of the entrances 1e of the four compressed air tank 1. Of course, it is also possible that for individual control of each compressed air tank 1 each have a control valve 19 at the input 1e of a compressed air tank 1 is arranged. This ensures that during operation of the system, the pressure in the system can be kept constant, for example at 500 bar. By means of the control and comparison unit 13, as explained below, starting from the determined in the pressurized water tank 2 by means of the sensors SN amount of water and the available volume in the compressed air tank 1 and 2 in the pressurized water tank for a given pressure, eg 500bar required amount be determined from compressed air, which may need to be refilled from the compressed air reservoir 18 via the control valve 19 in the compressed air tank 1. By means of the sensor SD, the pressure in a compressed air tank 1 is measured. The sensors SD, SN are thus connected via data lines 16 to the control valve 19 and the control and comparison unit 13.

The outlet 1a of the compressed air tank 1 is connected via a pressure line 5 to the inlet 2e of a pressurized water tank 2. Not shown are shut-off valves which are arranged between the compressed air tank 1 and the pressurized water tank 2. Further not shown are compressed air turbines, which are arranged between the outlet 1 a of the compressed air tank 1 and the inlet of the pressurized water tank 2.

The output 2a of a pressurized water container 2 is connected via a shut-off valve 6 and a pressure line 5 to the inlet E3 of the overpressure turbine 3. With regard to the arrangement of the overpressure turbine 3 and the constant pressure turbine 3a is here to the explanations to Fig. 1 directed. The outputs 2a of the pressurized water container 2 are each located at the lowest point of the pressurized water container 2. Furthermore, the outputs 2a of the pressurized water container 2 via a common pressure line 5 are interconnected. This pressure line 5 has a gradient in the direction of the turbine arrangement 3, 3a.

The overpressure turbine 3 and the constant pressure turbine 3a each have a controllable tail unit 7, 7a, via which the outlet pressure of the overpressure turbine 3 into the constant pressure turbine 3a and the feed quantity into the overpressure turbine 3a and the constant pressure turbine 3 can be regulated. As a result, the output power of the turbine arrangement 3, 3 a can be regulated. For this purpose, the inlet guide 7, 7a are connected via a data line 16 to the control and comparison unit 13. The positive pressure turbine 3a and the constant pressure turbine 3 are connected via a common drive shaft AW connected to a generator 4 for power generation. This generator 4 is connected to a power grid S or connectable to a power grid S.

The arrangement of overpressure turbine 3 and constant pressure turbine 3a is designed such that in the case of energy recovery through the arrangement of pressure turbine 3 and constant pressure turbine 3a led water from the pressurized water tank 1 is relaxed in a water reservoir 9.

The water reservoir 9 has an antechamber 10 for removing the water in the case of energy storage. This pre-chamber 10 has an opening 10a, which is designed such that the lower boundary of this inlet opening 10a above the bottom of the pre-chamber 10 is arranged. The upper boundary of the opening 10a is disposed below the water level (not shown) in the water storage 9. The limitation prevents heavy parts from getting into the pre-chamber 10 in the water. By immersing the upper edge below the minimum water level prevents air-containing water enters the antechamber, which can lead to disturbances of the high pressure pump 11 and impurities in the pressurized water tank 2. The impurities can lead to disturbances in the turbines 3, 3a. Furthermore, it is prevented that the foam generated by the water relaxation of the constant pressure turbine 3 passes through microbubbles in the water, in the prechamber 10 and the high pressure pump 11.

To the prechamber 10, a high pressure pump 11 is connected. The power of the high-pressure pump 11 takes place from the connected or connectable power grid S. In addition, a check valve 8 is provided in the connecting line 12 between the high-pressure pump 11 and pressurized water tank 2 , This check valve 8 serves to ensure that the built-up during the energy storage pressure in the pressurized water tank 2 causes no feedback to the high-pressure pump 11. Of course, the pressurized water container 2 at the access 2a of the connecting line 12 in the pressurized water container 2, a shut-off valve (not shown).

The system has a control and comparison unit 13. This control and comparison unit 13 is connected via a data line 16 with pressure sensors SD in the compressed air tank 1 and with level sensors SN in the pressurized water tank 2. The control and comparison unit 13 comprises a comparison device for comparing the instantaneous pressure in the pressurized water container 2 and the instantaneous pressure in the compressed air tank 1 and the instantaneous amount of water in the pressurized water container 2 with a desired pressure value. The control and comparison unit 13 is set up such that, depending on the result of the comparison, the compressed air tank 1 is supplied with compressed air from the compressed air reservoir 18 via a control valve 19.

The control and comparison unit 13 is connected to a data line 16 to a network computer 15 of a connected or connectable public or non-public power grid S. About the network computer 15, a request to the control and comparison unit 13 is made, whether the system is to be used for energy or energy storage or can.

For this purpose, the control and comparison unit 13 is connected via a data line 16 with the controllable inlet guide vanes 7, 7a of the turbines 3, 3a. This makes it possible to adjust the power required by the network computer 15 of the public power grid to the turbines 3, 3a. Further, the control and comparison unit 13 is connected via a data line 16 to the shut-off valve 6. This ensures that only in the case of energy recovery, the shut-off valve 6 is opened and a connection between the pressurized water tank 2 and turbines 3, 3a is made.

Furthermore, the control and comparison unit 13 is connected via a data line 16 to a control device (not shown) of the high-pressure pump 11. It is thus possible to convert the excess energy supplied to the system from the power grid S into the pressurized water tank 2 as required in the transport of water.

Fig. 3 shows an inventive system for energy storage and recovery. with compressed air and pressurized water tanks arranged in groups. Fig. 3 shows by way of example two groups each consisting of two compressed air tanks and a pressurized water tank.

To avoid repetition, the description of the Fig. 1 and 2 directed. At the in Fig. 3 Unlike the system shown Fig. 2 two compressed air tanks 1 connected to a pressurized water tank 2. The outputs 1a of the two compressed air tank 1 are connected via a pressure line 5 to the input 2e of a pressurized water tank 2. Thus, two compressed air tanks 1 and 2 pressurized water tank form a group (storage group). Of course, a plurality of compressed air tanks or a plurality of pressurized water tanks can be connected to one another in a group. Shut-off valves which are present between the inlet 2e of a pressurized water tank 2 and an outlet 1a of a compressed air tank 1 within a group are not shown.

The pressure water tanks 2 of the groups are at the outputs 2a with the overpressure turbine 3 (see explanations to Fig. 1 ) connected. Here, the outputs 2a of the pressurized water tank via a pressure line 5 are interconnected, wherein the pressure line 5 in the direction of the collector has a gradient.

At the in Fig.2 and Fig. 3 shown systems, the required water is filled before commissioning of the system in the pressurized water tank 2. Appropriately, the first-time filling of the pressurized water container 2 after the or the compressed air tank 1 is filled with compressed air. The required pressure in the compressed air tank 1 or pressurized water tank 2 is generated by means of the compressor 17 and filled by the compressed air reservoir 18 into or the compressed air tank 1. Depending on the required operating pressure, the pressure in the compressed air tank 1 and thus in the pressurized water tank 2 is increased to 10, 50, 100, 200 or 1000 bar.

By requesting energy through the network computer of the power grid S, the shut-off valve 6 between the pressurized water tank 2 and the turbines 3, 3 a is opened via the control and comparison unit 13 and thus the pressurized water in the pressurized water tank 2 of the overpressure turbine 3 and coupled with this constant pressure turbine 3a supplied. The amount of water flowing into the overpressure turbine 3 is controlled by the control and comparison unit 13. As a result, the power generated by the overpressure turbine 3 and the constant pressure turbine 3a is regulated. The coupled to the overpressure turbine 3 and constant pressure turbine 3a generator 4 generates the from Network computer 15 of the power grid S requested amount of energy and feeds them into the power grid S.

It is thus possible that the control and comparison unit 13 regulates the energy recovery and the energy storage in the system. The control and comparison unit 13 receives via corresponding data lines 16 from the network computer 15 of the power grid S specifications regarding the respective operating phase, ie whether the system is in the operating phase of energy recovery or energy storage.

LIST OF REFERENCE NUMBERS

1

Air receiver

1e

entrance

1a

output

2

Pressurized water tank

2e

entrance

2a

output

3

Reaction turbine

3a

Impulse turbine

E3

Input overpressure turbine

A3

Output overpressure turbine

E3a

Input synchronous turbine

A3a

Output synchronous turbine

AW

drive shaft

4

generator

5

Pressure pipe / connection cable

6

shut-off valve

7

Water inlet tail

7a

Water inlet tail

8th

check valve

9

water-tank

10

antechamber

10a

opening

11

High pressure water pump

12

connecting line

13

Control and comparison unit

15

network computer

16

data line

17

compressor

18

Compressed air storage

19

shut-off valve

S

power grid

SN

Sensor level

SD

pressure sensor

Claims (13)

1. A system for energy storage and recovery, comprising:

   at least one compressed-air tank (1),

   at least one pressurized-water tank (2) in communication with the at least one compressed-air tank (1),

   at least one turbine (3) in effective communication with the at least one pressurized-water tank (2),

   a generator (4) for generating electrical energy, and

   a high-pressure pump (11) for pumping water from a water reservoir (9) into the at least one pressurized-water tank (2),

   characterized in that

   the at least one turbine (3) in effective communication with the at least one pressurized-water tank (2) is a reaction turbine, which is connected in series with a constant pressure turbine (3a) in such a manner that a drive shaft (AW) of the reaction turbine (3) is connected to a drive shaft (AW) of the constant pressure turbine (3a) and a drive shaft (AW) of the generator (4) and that

   the constant pressure turbine (3a) is arranged between the reaction turbine (3) and the generator (4), wherein

   the generator (4) includes an interface for connection to a public power grid (S).
2. The system according to claim 1, characterized in that the drive shaft of the reaction turbine (3) and the drive shaft (AW) of the constant pressure turbine (3a) form a common shaft, or the drive shaft (AW) of the reaction turbine (3) and the drive shaft (AW) of the constant pressure turbine (3a) are coupled to each other via a rigid coupling, or the drive shaft (AW) of the reaction turbine (3) is connected to the drive shaft (AW) of the constant pressure turbine (3a) via a transmission,
   and that an outlet of the at least one pressurized-water tank (2) is connected to an inlet of the reaction turbine (3) and an outlet of the reaction turbine (3) is connected to an inlet of the constant pressure turbine (3a).
3. The system according to claim 2, characterized in that a means for pressure regulation of the inlet pressure of the constant pressure turbine (3a) is arranged between an outlet of the reaction turbine (3) and an inlet of the constant pressure turbine (3a).
4. The system according to any one of the preceding claims, characterized in that when a plurality of pressurized-water tanks (2) are provided, a connection line is present connecting the outlets of the pressurized-water tanks (2) with one another, wherein the pressurized-water tanks (2) are arranged in such a manner with respect to each other that the connection line has a gradient and has a sump at its lowest point, which is connected to an inlet of the turbine (3, 3a).
5. The system according to any one of the preceding claims, characterized in that wherein a stop valve (6) is provided at an inlet of the turbine (3, 3a).
6. The system according to any one of the preceding claims, characterized in that the at least one compressed-air tank (1) is in constant pressure equilibrium with the at least one pressurized-water tank (2), in such a manner that during energy storage and recovery the pressure in the at least one compressed-air tank (1) is equal to the pressure in the at least one pressurized-water tank (2).
7. The system according to any one of the preceding claims, characterized in that a compressed-air turbine is present between the at least one compressed-air tank (1) and the at least one pressurized-water tank (2).
8. The system according to any one of the preceding claims, characterized in that precisely one pressure line (5) is present between an outlet of the at least one compressed-air tank (1) and an inlet of the at least one pressurized-water tank (2) and is adapted to conduct compressed air from the at least one pressurized-water tank (2) to the at least one compressed-air tank (1) during energy storage and to conduct compressed air from the at least one compressed-air tank (1) to the at least one pressurized-water tank (2) during energy recovery.
9. The system according to claim 8, characterized in that a stop device is arranged in the pressure line (5), which is configured to block the pressure line (5) at a sudden pressure drop.
10. The system according to any one of the preceding claims, characterized in that the ratio of a volume of the at least one pressurized-water tank (2) to a volume of the at least one compressed-air tank (1) is 1:1, 1:2, 1:3, or 1:4.
11. The system according to any one of the preceding claims, characterized in that a control and a comparison unit (13) is provided which is configured, as a function of the load on a public power grid (S), to drive the high-pressure pump (11) with energy from the public power grid (S) to pump water from the water reservoir (9) into the at least one pressurized-water tank (2) when there is a surplus of energy in the public power grid (S),
    or to conduct pressurized water from the at least one pressurized-water tank (2) to the at least one turbine (3, 3a) and to feed the energy generated in the generator (4, 4a) to the public power grid (S), when there is a demand for energy in the public power grid (S).
12. The system according to claim 11, characterized in that, in the case of energy recovery, the control unit (13) is configured to regulate the power generated by the at least one turbine (3, 3a) by opening or closing of water inlet nozzles (7) connected to the turbine (3, 3a).
13. The system according to any one of the preceding claims, characterized in that a control and a comparison unit (13) is provided for comparing a current pressure in the at least one pressurized-water tank (2) and a current pressure in the at least one compressed-air tank (1) and a current water level in the at least one pressurized-water tank (2) with a set pressure value, wherein the control and the comparison unit (13) is configured in such a manner that compressed air is fed from a compressed-air reservoir (18) to the at least one compressed-air tank (1) as a function of the comparison result.

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