Energy conversion device

Abstract

The invention relates to a device for isothermal expansion and compression of a gas (3), which ensures the compression of the gas by consuming mechanical energy and the recovery of the mechanical energy by the expansion of the gas. The device comprises at least two liquid pistons (4, 41, 42) movable in at least two chambers (31, 32) each comprising a gas that can be compressed or expanded by the movement of said liquid pistons. Comprising at least one solid piston ensures the movement of the liquid piston in the chamber. Each chamber comprises an insert (51, 52) through which the liquid (4) and the gas can circulate, the insert comprising a through-unit (53) extending in a direction parallel to the direction of movement of the liquid piston in the insert. The apparatus comprises at least one first phase separator connected to the outlet of each of the chambers and to a tank (5) for storing pressurized gas.

Description

[0001] The present invention relates to a system for energy conversion and storage.

[0002] In the literature, gas compression and / or expansion by means of a liquid piston seems to be a promising solution for improving the energy efficiency of power plants, with the aim of achieving a thermodynamic evolution that is as isothermal as possible.

[0003] The state of the art is described, for example, in patent application FR 3036887, which uses pumps or turbines to achieve energy conversion between a mechanical actuator and the liquid in a liquid piston. One or more liquid piston compression stages are implemented in such a system to traverse the desired gas pressure range.

[0004] Various devices or equipment can be employed to increase heat exchange in the liquid piston compression chamber, such as spraying water droplets, running multiple chambers in parallel, adding heat exchange inserts, etc.

[0005] These devices give rise to many problems: in particular, to achieve near-isothermal compression / expansion, a large amount of heat exchange is required in the expansion chamber and / or the compression chamber, the value of which is several orders of magnitude higher than the exchanges present in the state of the art.

[0006] The device proposed in patent application FR 3036887 extends the compression / expansion time but uses simple technical solutions to achieve near-isothermal operation. However, as a result, these plants are rather large, occupying a large amount of space (about 50000 m3 for a 15 MW power plant), which leads to high operating costs.

[0007] Other techniques offer more compact solutions but are more complex to implement, which means that the operating costs cannot be reduced.

[0008] Therefore, the complexity and cost of such devices are an obstacle to the development of this technology.

[0009] The present invention provides an alternative solution that is easy to implement and whose dimensions can be designed to suit the application for which it is specifically designed.

[0010] To this end, the present invention relates to a device for the isothermal expansion and compression of a gas, ensuring the compression of said gas by consuming mechanical energy and the recovery of mechanical energy by the expansion of said gas, said device comprising:

[0011] - at least one first and at least one second liquid piston, which are respectively able to move in a first and a second chamber, each of said at least one first and second chamber comprising a gas that can be compressed or expanded by the movement of said at least one first or second liquid piston,

[0012] - An actuator capable of moving the at least first and second liquid pistons in the first and second chambers,

[0013] Each of the at least one first and second chambers respectively includes at least one first and at least one second perforated insert, through which the liquid and the gas can flow.

[0014] The device according to the invention is remarkable in that the actuator is a mechanical actuator including at least one solid piston, wherein the perforated insert includes a through unit that extends between a first unit hole opening at one end of the insert and a second unit hole opening at the second end of the insert, and the unit is oriented in a direction parallel to the moving direction of the liquid piston in the insert or inclined with respect to the moving direction of the liquid piston. Finally, the device further includes at least one first phase separator connected to a first outlet of the first chamber and a second outlet of the second chamber.

[0015] Advantageously, the phase separator is connected to a storage tank of pressurized gas.

[0016] According to an advantageous embodiment, the device according to the invention includes a second separator respectively connected to the first and second outlets of the first and second chambers, wherein the first separator includes a first internal pressure corresponding to the internal pressure of the gas included in the tank of the pressurized gas, and wherein the second separator includes a second internal pressure corresponding to the atmospheric pressure.

[0017] Preferably, the first and second separators are in fluid communication with each other to allow the liquid to flow from the first separator to the second separator.

[0018] Even more preferably, the device includes: a first air intake device that ensures the circulation of air at atmospheric pressure between the at least one first chamber and the second separator; and a second air intake device at atmospheric pressure between the at least one second chamber and the second separator.

[0019] In addition, the device includes a third air intake device for compressing the circulation of air between the first chamber and the first separator and a fourth air intake device for compressing the circulation of air between the second chamber and the first separator.

[0020] Even more preferably, the device includes a first low-flow control valve for the circulation of fluid from the first separator to the first chamber and a second low-flow control valve for the circulation of fluid from the first separator to the second chamber.

[0021] According to an advantageous embodiment, the device includes a regulating valve, which is arranged at a safety pressure between the first chamber and the first separator and / or between the second chamber and the first separator, so that a certain volume of liquid can be discharged from the at least one first or second liquid piston into the first separator.

[0022] Furthermore, each of the first and second chambers is preferably also fluidly connected to a fluid / fluid exchanger, which is capable of maintaining the at least one first and second liquid pistons at ambient temperature, preferably at an ambient temperature with an allowable temperature variation of plus or minus 10 °C. The fluid / fluid exchanger preferably includes a pump, a fluid / gas exchanger or a fluid / fluid exchanger. If the exchanger is a fluid / gas exchanger, it optionally includes an electric fan, and optionally includes at least one control valve.

[0023] Advantageously, the insert includes a core of a structural material, and the core of the structural material includes an expanded honeycomb structure.

[0024] More advantageously, the mechanical actuator includes a magnetic-actuated linear motor.

[0025] In one embodiment, the mechanical actuator includes a motor associated with a crankshaft.

[0026] In yet another variant, the mechanical actuator includes a motor associated with a worm screw.

[0027] The invention also relates to a device including at least two devices as defined above, the mechanical actuators of the at least two devices being mechanically coupled to operate together, and wherein the device includes a first phase separator shared by the at least two devices, the shared first phase separator being connected to a first outlet of the first chamber of the device and a second outlet of the second chamber of the device, and the first phase separator being connected to a storage tank of a shared pressurized gas.

[0028] In an embodiment, the device includes at least two devices each including two phase separators, a second separator being shared by the at least two devices, the second separator being connected to the first and second outlets of the first and second chambers of each of the at least two devices, the shared first separator including a first internal pressure corresponding to the internal pressure of the gas included in the tank of the shared pressurized gas, and the second separator including a second internal pressure corresponding to atmospheric pressure.

[0029] Finally, the invention relates to a method for implementing a device as defined above, the method including the following steps:

[0030] - Actuating the mechanical actuator,

[0031] - Move the at least one solid piston to move the first liquid piston in the first chamber and the second liquid piston in the second chamber, the first and second liquid pistons moving in opposite directions, the first liquid piston compressing the gas in the insert of the first chamber to a first predetermined pressure, and the second liquid piston creating a vacuum in the insert of the second chamber until a second pressure.

[0032] - When the first pressure is reached,

[0033] Open the intake device between the first chamber and the first phase separator to discharge the pressurized gas from the first chamber to the first separator until the liquid piston completely passes through the insert and reaches the first outlet of the first chamber, while air intake in the second chamber is carried out.

[0034] Thus, the device according to the present invention is a reversible gas compressor that is capable of compressing a gas while consuming mechanical energy, but is also capable of recovering mechanical energy by expanding the gas. The thermodynamic evolution of the gas is quasi-isothermal due to the compression / expansion of the liquid piston, enabling these pressure changes to be achieved with low energy losses. The properties of the gas and the liquid can be adapted to the requirements of the intended applications of the device (air, hydrogen, methane, gas, water, etc.).

[0035] In the compression mode, in the context of the non-limiting embodiments presented below, the principle is based on the gas compression by the liquid piston, which is moved by the solid piston. The solid piston is directly driven by a linear motor, which is a moving part containing magnets, or is driven by another piston movement system (linkage, crank, rack, etc.). When the solid piston moves, it pushes the liquid piston into the closed compression chamber (vertical cylinder). The reduction in volume results in gas compression.

[0036] The cylindrical compression chamber is subdivided into many small volumes by a heat exchange insert, which consists of an extruded 2D pattern, the cells of which extend in the direction of the liquid piston (also known as a "honeycomb" structure, made of aluminum or other thermally conductive material).

[0037] The fluid properties of the liquid piston enable small liquid pistons to be formed in each honeycomb cell, ensuring a perfect seal between the liquid and the gas medium. The presence of the insert (honeycomb) provides a very large contact surface with the gas and a significant heat exchange potential. The heat exchange between the gas and the insert, the heat transfer within the insert, and the heat capacity of the insert itself ensure that the temperature of the gas remains close to the initial temperature of the assembly (quasi-isothermal) during compression.

[0038] Thus, the heat exchange insert functions as a regenerative exchanger, continuously transferring thermal energy from the gas to the insert by convection / conduction, storing the thermal energy due to a moderate increase in its temperature (the effect of its heat capacity), and then transferring this thermal energy to the liquid by convection / conduction.

[0039] Other advantages and features of the present invention will become apparent by looking at the detailed description and the drawings of the completely non-limiting embodiments, wherein:

[0040] Figure 1 is a schematic view of a first embodiment of the device according to the present invention, viewed from the side,

[0041] Figure 2 is a schematic view of a second embodiment of the device according to the present invention, viewed from the side,

[0042] Figure 3 is another schematic view of a third embodiment of the device according to the present invention, viewed from the side,

[0043] Figure 4 shows a perspective view of an exemplary embodiment of the device according to the present invention, which implements several devices in accordance with the present invention,

[0044] Figure 5 is another schematic view of a fourth embodiment of the device according to the present invention, viewed from above, and

[0045] Figure 6 is an example of an insert with a honeycomb structure, which is deployed and positioned in a chamber of the device according to the present invention, and the insert in the chamber is visible from below.

[0046] Figure 1 shows an embodiment of a device in accordance with the present invention for expanding and compressing a gas, enabling mechanical energy to be stored and recovered.

[0047] Thus, the device includes a mechanical actuator 1, which includes, for example, a crankshaft 10 (a mechanical member that converts reciprocating linear motion into continuous rotation and continuous rotational motion into reciprocating linear motion according to a connecting rod 11 / crank 12 system).

[0048] A motor (not shown) converts the energy source. Generally, the energy source is electrical energy. However, alternative rotational drive power sources can be considered.

[0049] It should be noted that the system does not require a "starter" to initiate rotation: for example, in the energy release mode (expansion), the crankshaft rotates directly through the compression chamber / expansion chamber without the assistance of an electric motor / generator.

[0050] The crank 12 is connected to two solid pistons 21 and 22, and each solid piston is respectively installed in the first chamber 31 and the second chamber 32 to move.

[0051] Each of the chambers 31 and 32 respectively has liquid pistons 41 and 42, and these two liquid pistons move in the chambers by the push of the solid pistons 21 and 22 moving in the same chamber.

[0052] Each of the first chamber 31 and the second chamber 32 is made of a bent pipe, and is characterized in that:

[0053] - The first pipe portions 33 and 34, which respectively extend along a substantially horizontal direction, and

[0054] - The second pipe portions 35 and 36, which respectively extend along a substantially vertical direction.

[0055] It should be understood that the present invention is not limited to the use of angled chambers (in other words, they can have different shapes without exceeding the scope of the present invention).

[0056] The two solid pistons 21 and 22 can respectively move in the first pipe portions 33 and 34, and are driven to move by the actuator 1.

[0057] When pushed or sucked by the movement of the associated solid pistons 21 or 22, the two liquid pistons 41 and 42 can move in the first pipe portions (33, 34) and the second pipe portions (35, 36) of the chambers 31 and 32.

[0058] The second pipe portions 35 and 36 are designed to receive and discharge the gas 3 (such as air), so that the movement of the liquid 4 from the liquid pistons 41 or 42 into the chambers 31 and 32 causes the compression or expansion of the gas 3.

[0059] For this purpose, each of the chambers 31 and 32 respectively includes outlets 37 and 38, so as to especially ensure the entry and exit of the gas into and from the second pipe portions 35 and 36 of the first chamber 31 and the second chamber 32.

[0060] The first outlet 37 and the second outlet 38 are connected to the phase separator 2, and the phase separator accommodates some of the liquid 4 in the gas 3 and the liquid that may be discharged from the chambers 1 and 2.

[0061] The phase separator 2 is connected to the storage tank 5 of the pressurized gas.

[0062] The flow of the gas 3 and the possible liquid 4 among the phase separator 2, the chambers 31 and 32, and the storage tank will be explained below.

[0063] The second pipe segments 35 and 36 respectively accommodate inserts 51 and 52.

[0064] The inserts 51 and 52 are perforated inserts, i.e. they each have a cell in which the liquid from the liquid pistons 41 and 42 can flow and which can also accommodate the gas compressed or expanded in the chambers 31 and 32.

[0065] The inserts 51 and 52 are special in that they are made of a core of expandable sandwich material, thus forming inserts in which the cells extend directly through the inserts.

[0066] The core of the expandable sandwich material of the insert consists of multiple layers of plastically deformable material, which are connected together by bonding points (welding, gluing, etc.) extending along lines along the length of the layers. By moving the two outer layers of the sandwich structure away from each other, a cell is formed between two adjacent material layers and the connecting lines, thus creating a cell extending along the entire length of the multi-layer structure.

[0067] In an alternative embodiment (not shown), the insert can be made by winding stacked metal plates, including for example flat plates and corrugated plates (forming a series of depressions and protrusions), which are positioned one on top of the other and wound together. Then, a cell is formed between the depressions of the corrugated plate and the surface of the adjacent plate, and then the cell extends along the direction of movement of the liquid piston in the chamber accommodating the insert.

[0068] Therefore, the inserts used in the present invention have the feature of a so-called "through cell", i.e. each cell has two openings, each opening located at the end of the cell, the first cell opening leading to one end of the insert and the second opening leading to the other end of the insert. Figure 6 The second tube part 35 (or 36) of the chamber 31 (or 32) is shown, which is cut away to better show the insert 51 or 52.

[0069] Each of the inserts 51 or 52 is preferably made of aluminum and has continuous cells 53, which together form a honeycomb pattern and include a first end opening 54 (visible in the figure) through which the gas 3 or liquid 4 can enter or leave the insert. Additional openings (not shown in the figure but schematically shown by the arrow 55) open near the outlets 37 and 38 of each of the chambers 31 and 32.

[0070] Each cell 53 of the insert structure 51 or 52 forms a microtube in which the gas 3 and liquid 4 can enter and leave, and each microtube is oriented parallel to or mainly parallel to the direction of movement of the liquid 4 and gas 3 in the chamber 31 or 32 (more precisely, the axis of each microtube is parallel to the axis of the second tube part 35 or 36 accommodating it).

[0071] "Main parallel" refers to the geometric orientation of the unit entry and exit points relative to the axis of the insert. This orientation is parallel or substantially parallel to the axis of the insert, or is inclined relative to the axis of the insert due to the shape of the microtubes of the unit. In practice, the unit can be straight, in which case the microtubes are cylindrical, or the unit can be twisted, in which case the microtubes form a helix.

[0072] Figure 1 Two fluid / fluid exchangers 71 and 72 are also shown: each of the first chamber 31 and the second chamber 32 has a fluid / fluid exchanger 71 and 72 respectively (as shown at the bends of chambers 31 and 32 in the figure). The fluid is preferably water.

[0073] In this example, these fluid / fluid exchangers 71 and 72 are each connected to a pump 83, a fluid / air exchanger 84, an electric fan 85, and a control valve 86. This assembly ensures that the liquid 4 (from the liquid piston) remains at a temperature close to the ambient temperature (plus or minus 10 degrees Celsius).

[0074] A single pump can be provided without departing from the scope of the present invention.

[0075] Similarly, the fluid / air exchanger 84 can be replaced by a fluid / fluid exchanger.

[0076] The pump 83, the fluid / air exchanger 84, the electric fan 85, and the control valve 86 are not shown in Figure 1 However, they can be found in the Figure 3 illustrated embodiment. These elements keep the fluid in the cooling circuit at a temperature close to ambient (plus or minus 5 degrees Celsius).

[0077] Now show Figure 1 the operating mode of the device shown:

[0078] The motor of the mechanical actuator is, for example, a synchronous rotating motor with permanent magnets and can be associated with a reversible speed reducer (target speed 30 rpm).

[0079] This motor allows the crankshaft 10 to rotate: the connecting rods 11 that connect the crankshaft cranks to each solid piston 21 and 22 drive the solid pistons 21, 22 in a linear motion in an alternating manner: when piston 21 is pulled, piston 22 is pushed, and when piston 22 is pulled, piston 21 is pushed.

[0080] The working principle in the compression mode is as follows: the solid piston 21 pushes the liquid piston 41 into the closed chamber 31. The reduction in the gas volume caused by the liquid piston 41 being pushed into the insert 51 increases the gas pressure in the insert 51.

[0081] Each unit 53 acts like a small liquid piston, ensuring a perfect seal between the liquid and the gaseous medium. The insert 51 serves as a regenerative exchanger between the gas and the liquid piston fluid. The presence of the insert 51 provides a large contact surface with the gas 3 and offers a high heat exchange potential. The heat exchange between the gas and the insert, the heat transfer within the insert, and its own heat capacity keep the temperature of the gas during compression close to the value of the initial temperature of the assembly. That's why the operation is considered quasi-isothermal.

[0082] When the air pressure reaches the desired value, the check valve 13 opens, allowing the compressed gas 3 to be released from the chamber 31.

[0083] The liquid piston 41 continues to rise in the chamber 31 until it touches the end wall of the chamber to release all the compressed gas 3.

[0084] The solid motor piston that has reached the end of its stroke changes direction and repeats the same process on the second piston 22 of the device consisting of exactly the same components. After the compression in the first chamber 31 is completed, the descent of the liquid piston 41 allows the low-pressure gas 3 to enter the chamber 31 through the opening of another valve 14 (check valve).

[0085] Regarding the thermal energy captured in the gas by the insert 51 (honeycomb structure) during compression, this energy raises the temperature of the insert 51 by a few degrees Celsius, indicating the storage of this thermal energy in the material.

[0086] As the liquid piston 41 rises and fills the entire volume of the chamber 31 at the end of compression, the hot insert 51 carrying the thermal energy comes into contact with the liquid 4.

[0087] Since the solid / liquid heat transfer between the insert 51 and the liquid 4 of the liquid piston 41 is much stronger than the solid / gas heat transfer between the insert 51 and the gas 3, significant heat exchange occurs between the wall and the liquid 4, causing the insert 51 - liquid 3 assembly to tend towards a slightly higher equilibrium temperature (one-tenth of a degree higher than the initial temperature of the liquid) and thus lower than the temperature of the insert 51 before contact with the liquid 4.

[0088] When the new volume of the gas 3 to be compressed enters, the liquid 4 forming the descending liquid piston 41 passes through the fluid / fluid heat exchanger 71, whose function is to keep the temperature of the liquid piston 41 stable over time.

[0089] At the outlet of the chamber 31, the compressed gas 3 passes through the gas / liquid separator 2 and may be able to collect a part of the liquid 4 that forms the liquid piston if it exceeds the top dead center of the chamber 31.

[0090] At the outlet of this separator 2, the gas 3 is conveyed to its storage or to another gas compression stage in the storage tank 5.

[0091] The liquid 4 retained in the separator helps to establish a liquid reserve for the pistons 41 and 42, a part of which can be redirected to the compression chambers 31 and 32 to maintain a liquid volume that can ensure the continuous operation of the system.

[0092] The valves 13 and 16 are connected between the gas / liquid separator 2 (whose internal pressure is equal to the gas compression pressure) and the base of the compression chamber 31 (whose pressure varies between the inlet pressure and the maximum pressure). The valves 13 and 16 are used to convey the compressed gas between the compression chamber and the separator, where the gas may include a part of the liquid piston fluid.

[0093] It should be noted that the outlet 38 of the chamber 32 also has two check valves 15 and 16, and the valve 15 ensures the air supply at atmospheric pressure (or low pressure).

[0094] The check valves 13, 14, 15 and 16 can be replaced by pilot valves.

[0095] Now the operating principle of the gas 3 in the expansion mode will be referred to.

[0096] The reverse operation of the device (i.e., converting pressure energy into electrical energy) works based on the same general principle, and can be achieved in the Figure 2 shown embodiment by replacing the valves 13 to 16 with pilot valves 64, 61, 62 and 65.

[0097] The compression chamber 32 initially filled with liquid admits a certain volume of pressurized gas 3 through the valve 65.

[0098] The pressure applied to the liquid piston 42 is applied to the solid piston 22, thereby generating mechanical work.

[0099] This mechanical work is converted into electrical energy through the crankshaft / generator assembly.

[0100] When the volume of the admitted pressurized gas 3 is sufficient, the valve 65 closes, and the expansion of the gas 3 continues to move the solid piston 22.

[0101] When the gas 3 reaches a pressure close to the low pressure (usually atmospheric pressure), the movement (and energy conversion) stops. During the intake and expansion phases, the opposite liquid piston 41 moves from its low point to its high point, discharging the expanded gas 3 at atmospheric pressure through the valve 61 to the outside.

[0102] Therefore, the chamber 32 is an expansion chamber, and the heat exchange insert 52 is cooled by the gas 3 during expansion, while maintaining the expansion of the gas 3 in a quasi-isothermal evolution process.

[0103] Then, the liquid / liquid exchanger 12 heats the liquid piston 42.

[0104] Figure 2The embodiment shown is characterized by a second phase separator 6 at atmospheric pressure, which is capable of collecting any liquid portion 4 from the liquid pistons 41 or 42 at low pressure when the liquid piston 42 (or 41 when the liquid piston 42 acts via the compressed gas 3) descends.

[0105] In Figure 2 the embodiment shown, the mechanical actuator comprises a single solid piston 23 which moves in one direction in the chamber 31 or in the opposite direction in the chamber 32.

[0106] This is a magnetic piston for a linear motor.

[0107] The operating mode is the same as Figure 1 the operating mode of the device shown.

[0108] The difference lies in the presence of a second low-pressure phase separator 6.

[0109] As is known, the function of the phase separators 2 and 6 is to recover the liquid 4 discharged at the end of the stroke of the liquid pistons 41 or 42 while allowing the gas 3 to continue to move forward.

[0110] The volumes of the separators 2 and 6 are chosen such that the velocity of the gas 3 is sufficiently reduced to allow the liquid 4 to settle naturally to the bottom of the buffer volume.

[0111] Other supplementary solutions can be considered, such as using a cyclone system or coalescing grids. The gas pressure drop in this element must be kept low.

[0112] The hydraulic connection 20 between the phase separator 2 and the bottoms of the compression chambers 31 and 32 (which can be in the second vertical pipe sections 35 and 36 or in the first horizontal pipe sections 33 and 34) enables a small flow of liquid 4 to enter continuously to compensate for entrainment losses during the flushing process.

[0113] Flow control valves 24 are installed in each hydraulic connection, thus allowing the flow rate to be changed in order to find the optimal setting experimentally.

[0114] Each of the liquid pistons 41 and 42 (respectively) has valves 61 and 62 for releasing the liquid 4 into the unpressurized second separator 6 in the case of overpressure in the chambers 31 and / or 32.

[0115] When the gas 3 is released at atmospheric pressure, a lift pump 63 between the two separators 2 and 6 returns the liquid 4 lost in the unpressurized separator 6 in expansion mode to the pressurized separator 2.

[0116] Two additional valves 64 and 65 transfer the compressed gas between the compression chambers 31 and 32 and the separator 2, which can include a part of the fluid of the liquid piston.

[0117] If the liquid buffer volume 4 is sufficient, the pump 63 operates intermittently and infrequently. The pump is regulated based on the liquid levels in the two separators 2 and 6.

[0118] Figure 3 The illustrated embodiment relates to the use of a device that includes three solid pistons and six liquid pistons, and the "double-acting" piston principle optimizes the use of mechanical parts.

[0119] In fact, by increasing the number of pistons, high power levels (tens or hundreds of megawatts) can be achieved. Power can also be increased by disproportionately increasing the piston and chamber diameters, but increasing the number of pistons and chambers is preferred. On the one hand, there are optimally sized devices that are easy to transport (e.g., for high-power versions, the piston diameter is 300 mm to 2000 mm). On the other hand, if there is a reasonable phase shift between the settings of two pistons, increasing the number of pistons reduces the amplitude of the power variation exchanged with the power grid.

[0120] Increasing the system outlet pressure can also be achieved by staged compression using a cascade compressor as described below.

[0121] In the case of a stage where the inlet pressure is higher than atmospheric pressure (for high-pressure compression), the design of the piston translation system can advantageously utilize a 1-to-1 coupling opposite to the piston. In fact, the high-pressure intake force in one chamber is offset by the high-pressure compression force in the opposite chamber.

[0122] More specifically, the double-acting operation has the following advantages: the high-pressure intake force in one chamber is directly reused for the high-pressure compression force in the opposite chamber without passing through mechanical power components (such as connecting rods, crankshafts, or motor / generators).

[0123] Generally, whether single-acting or double-acting, increasing the number of solid pistons fixed to the same crankshaft, but cleverly out of sync, helps to limit the torque and power variations during system operation. By limiting these variations, the stress on the components can be kept minimized, the reliability of the assembly can be improved, and the need for oversized components can be limited.

[0124] Therefore, Figure 3 The mechanical actuator 1 of the illustrated device includes three pistons, and only one of these pistons (piston 25) is shown on the mechanical actuator (the pistons are out of sync by 120°).

[0125] Compared with Figure 1 and Figure 2 the illustrated embodiment, this embodiment achieves a greater pressure.

[0126] In this embodiment, three consecutive compression or expansion stages are achieved, each compression chamber corresponding to the compression stage to be reached. For example, the first chamber has a compression stage of 11 bar, the second chamber has a stage capable of increasing the compression from 11 bar to 70 bar, and the third chamber is capable of increasing the compression from 70 bar to 300 bar.

[0127] It is also possible to allow two of these chambers to form medium and high pressure stages.

[0128] Figure 3 The illustrated embodiment particularly includes a first control valve 91 for safety pressure provided between the first chamber 31 and the first separator 2, and a second control valve 92 for safety pressure provided between the second chamber 32 and the first separator 2, so that a certain volume of liquid can be discharged from the at least one first or second liquid piston into the first separator 2.

[0129] Figure 4 An apparatus according to the present invention is shown, which includes a series of devices according to the present invention.

[0130] A common crankshaft-type mechanical actuator drives twelve pairs of solid pistons 21 and 22 by the movement of a crank 12 mounted on a shaft rotatable about its axis. These pistons can move in twelve pairs of chambers 31, 32, and the crank is connected to the solid pistons 21, 22 by connecting rods 11.

[0131] It should be noted that all the outlets 37 and 38 of chambers 31 and 38 are connected together to the first phase separator 2 and the second phase separator 6 at atmospheric pressure: in other words,

[0132] The pressurized phase separator 2 is connected to:

[0133] - The valves 64 of chamber 31, all the valves 64 being connected to the same discharge pipe, and

[0134] - The valves 65 of chamber 32, all the valves 65 being connected to another common discharge pipe.

[0135] Furthermore, all the valves 61 of chamber 31 are connected to another common discharge pipe connected to the second separator, and all the valves 62 of chamber 32 are also connected to another common discharge pipe connected to the second separator 6 at atmospheric pressure.

[0136] It should be noted that in Figure 2 、 3 and 4, the valves 61 and 62 are low pressure (or atmospheric pressure) intake valves. They have the same function as the Figure 1 valves 14 and 15 shown.

[0137] In this exemplary embodiment, the solid pistons 21 and 22 have a diameter of 2.5 m and a stroke of 1 m.

[0138] The discharge pressure is approximately 11 bar, the inlet pressure is 1 bar, and the compression time is 1 second. A motor is used to operate a mechanical actuator. However, two motor / pump assemblies with a rated power less than that of the main motor are also required to operate the cooling circuit (pump 83) and to convey the liquid 4 from the separator 6 to the separator 3 (pump 63). The shaft speed is approximately 30 rpm.

[0139] The total floor area of such a device is approximately 7 m high, 8 m wide, and 45 m long.

[0140] At a frequency of 12 Hz, an average power of 15 MW is achieved with a variation amplitude of less than 0.8 MW.

[0141] The acceleration time to reach full speed is approximately one second (from 10% to 100% of the rated power).

[0142] The expected start-up time (from a complete stop to 100% rated power) is approximately 10 seconds.

[0143] Once started, the system power can be easily adjusted by modifying the rotational speed of the motor / generator (and the crankshaft) or by controlling the regulating valves 61, 62, 64, and 65. In this way, a variation range of 20% to 100% of the rated power can be utilized, and with a fast response time (approximately one second).

[0144] Figure 5 Yet another embodiment is shown, where five chambers 31, 31’, 31”, 32, 32’ are arranged in a star configuration and are associated with a double-acting piston 26: The use of a double-acting cylinder / piston 26 not only increases the power output of the same number of pistons but also improves the management of liquid leakage through the piston rings. The liquid passing through the piston seals simply flows into the opposite chamber without having to discharge the leaked liquid.

[0145] It is clear from the above description how the present invention converts mechanical motion into gas pressurization energy and how this energy is used to generate mechanical motion.

[0146] It should be understood that the present invention is not limited to the implementations of the examples specifically described above and shown in the drawings, but extends to the implementation of any equivalent means.

[0147] In particular, the application of the method is not specific to air gas and water fluid. The present invention contemplates other applications, such as the compression / expansion of (H2, CO2, CH4, etc.) using water (which can also be an ionic liquid, solvent, oil, organic liquid, etc.) as the liquid piston fluid.

Claims

1. An apparatus for the isothermal expansion and compression of a gas (3), which ensures the compression of the gas (3) by consuming mechanical energy and the recovery of mechanical energy by the expansion of the gas (3), the apparatus comprising: - at least one first and at least one second liquid piston (4, 41, 42) capable of moving in a first and a second chamber (31, 32) respectively, each of the at least one first and second chambers (31, 32) including a gas (3) capable of being compressed or expanded under the action of the movement of the at least one first or second liquid piston (4, 41, 42), - an actuator (1) capable of moving the at least one first and second liquid piston (4, 41, 42) in the first and second chambers (31, 32), each of the at least one first and second chambers (31, 32) respectively including at least one first and at least one second perforated insert (51, 52) through which the liquid (4) and the gas (3) can flow, characterized in that the actuator (1) is a mechanical actuator including at least one solid piston (21, 22), wherein the perforated insert (51, 52) includes a through unit (53) extending between a first unit opening (54) opening at one end of the insert (51, 52) and a second unit opening (55) opening at the second end of the insert (51, 52), the unit (53) being oriented along a direction parallel to the direction of movement of the liquid pistons (41, 42) in the insert (51, 52) or in a direction inclined with respect to the direction of movement of the liquid pistons, and wherein the apparatus further includes at least one first phase separator (2) connected to a first outlet (37) of the first chamber (31) and a second outlet (38) of the second chamber (32).

2. The device according to claim 1, characterized in that, The phase separator (2) is connected to a storage tank (5) of pressurized gas (3).

3. The device according to claim 2, characterized in that, The apparatus includes a second separator (6) connected to the first and second outlets (37, 38) of the first and second chambers (31, 32) respectively, wherein the first separator (2) includes a first internal pressure corresponding to the internal pressure of the gas (3) included in the container (5) of the pressurized gas, and wherein the second separator (6) includes a second internal pressure corresponding to atmospheric pressure.

4. The device according to claim 3, characterized in that, The first and second separators (2, 6) are in fluid communication with each other to allow the liquid (4) to flow from the first separator (2) to the second separator (6).

5. The device according to any one of claims 3 or 4, characterized in that, The apparatus includes a first intake device (61) that ensures the circulation of air at atmospheric pressure between the at least one first chamber (31) and the second separator (6), and wherein the apparatus includes a second intake device (62) at atmospheric pressure between the at least one second chamber (32) and the second separator.

6. The device according to any one of claims 3, 4 or 5, characterized in that, The device includes a third air intake device (13, 64) that ensures the circulation of compressed air between the first chamber (31) and the first separator (2), and wherein the device includes a fourth compressed air intake device (16, 65) between the second chamber and the first separator (2).

7. The device according to any one of claims 3 to 6, characterized in that, The device includes a first low-flow control valve (24) that ensures the circulation of fluid from the first separator (2) to the first chamber (31), and wherein the device includes a second low-flow control valve (24) that ensures the circulation of fluid from the first separator (2) to the second chamber (32).

8. The device according to any one of claims 3 to 7, characterized in that, The device includes regulating valves (91, 92) arranged at a safety pressure between the first chamber (31) and the first separator (2) and / or between the second chamber (32) and the first separator (1) so that a certain volume of liquid can be discharged from the at least one first or second liquid piston into the first separator (2).

9. The device according to any one of the preceding claims, characterized in that, Each of the first and second chambers (31, 32) is fluidly connected to a fluid / fluid exchanger (71, 72) that can keep the at least first and second liquid pistons (41, 42) at ambient temperature, preferably at ambient temperature with an allowable temperature variation of plus or minus 10 °C. The fluid / fluid exchanger (71, 72) preferably includes a pump (83), a fluid / air exchanger (84) or a fluid / fluid exchanger. If the exchanger is a fluid / gas exchanger (84), it optionally includes an electric fan (85), and optionally includes at least one control valve (86).

10. The device according to any one of the preceding claims, characterized in that, The inserts (51, 52) include a core of structural material that includes an expanded honeycomb structure.

11. The device according to any one of the preceding claims, characterized in that, The mechanical actuator (1) includes a magnetic actuator linear motor (23).

12. The device according to any one of the preceding claims, characterized in that, The mechanical actuator (1) includes a motor associated with a crankshaft.

13. The device according to any one of the preceding claims, characterized in that, The mechanical actuator includes a motor associated with a worm screw.

14. A device comprising at least two devices according to any one of the preceding claims, characterized in that, The mechanical actuators (1) of the at least two devices are mechanically coupled to operate together, and wherein the device includes a first phase separator (2) shared by the at least two devices. The shared first phase separator is connected to a first outlet (37) of the first chamber (31) of the device and a second outlet (38) of the second chamber (32) of the device. The first phase separator (2) is connected to a storage tank (5) of shared pressurized gas.

15. The device according to claim 14, wherein the device comprises at least two devices according to claim 3. The device includes a second separator (6) shared by the at least two devices, the shared second separator (6) being connected to the first and second outlets (37, 38) of the first and second chambers (31, 32) of each of the at least two devices, wherein the shared first separator (2) includes a first internal pressure corresponding to the internal pressure of the gas included in the tank (5) of the shared pressurized gas, and wherein the second separator (6) includes a second internal pressure corresponding to atmospheric pressure.

16. A method for implementing the device according to any one of claims 1 to 13, characterized in that, The method includes the following steps: - Actuating the mechanical actuator (1), - Moving the at least one solid piston (21, 22, 23) to move the first liquid piston (41) in the first chamber (31) and the second liquid piston (42) in the second chamber (32), the first and second liquid pistons (41, 42) moving in opposite directions, the first liquid piston (41) compressing the gas (3) in the insert (51) of the first chamber (31) to a first predetermined pressure, and the second liquid piston (42) creating a low pressure in the insert (52) of the second chamber (32) until a second pressure, - When the first pressure is reached, Opening the intake device (13) between the first chamber (31) and the first phase separator (2) to discharge the pressurized gas (3) from the first chamber (31) to the first separator (2) until the liquid piston (41) completely passes through the insert (51) and reaches the first outlet (37) of the first chamber (31), while sucking air (14) into the second chamber (32).

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