IMPROVED SYSTEM AND METHOD FOR ENERGY STORAGE AND RELEASE

Abstract

- Improved system and method for energy storage and release. - The invention relates to a method for storing and releasing energy, comprising: a heat transfer step (Tc) from a first material (M1), which is in a liquid state and comprises at least aluminum and magnesium, to a second material (M2), also in a liquid state, said first material (M1) being cooled to solidification, said second material (M2), thus heated, passing into a supercritical fluid state; and a transformation step (Te) of the mechanical energy of the second material (M2) in the supercritical fluid state into electrical energy (Ee). - The invention is particularly suited to the repeated storage and release of energy to supply buildings with electricity and / or heating. - Figure for the abstract: Figure 1.

Description

Title of the invention: IMPROVED SYSTEM AND METHOD FOR ENERGY STORAGE AND RELEASE

[0001] The present invention relates to the general field of energy management, and more specifically to energy storage and release.

[0002] More particularly, the invention relates to a method of storing and releasing energy, as well as an energy storage and release system.

[0003] Energy management is a major technical issue arising at the dawn of the third industrial revolution, where energy production, storage and distribution must imperatively be, on the one hand, decarbonized, i.e., in practice as neutral as possible with regard to their environmental impact, and on the other hand, efficient, i.e., present a correct yield for a controlled cost.

[0004] Energy production, particularly electrical energy, has long been carried out primarily from fossil fuel or nuclear sources. While fossil fuel and nuclear energy sources are relatively easy to store, their storage also presents major drawbacks, including risks of accidents, both for the environment (short-term pollution such as an oil spill, or long-term pollution such as a nuclear accident) and for people.

[0005] There is therefore a willingness on the part of states and certain innovative companies to promote new alternatives with regard to both energy production and its storage.

[0006] It has therefore been proposed to store quantities of electrical energy produced by renewable energy sources using accumulators, such as battery packs. This has been achieved to some extent with success in certain vehicles, mainly passenger cars.

[0007] That being said, even though significant improvements have been made in recent years with regard to energy storage, and in particular electricity storage, by means of batteries, these still present significant drawbacks which have not yet been overcome, in particular for certain uses.

[0008] Indeed, while current batteries can store electrical energy produced by various energy sources, they can do so only in relatively limited quantities. Batteries are not suitable for storing very large amounts of energy due to their high cost, relatively limited storage capacity, and significant environmental impact during their manufacture, disposal, and / or recycling.

[0009] Furthermore, current batteries have charge / discharge cycles, i.e., energy storage and release cycles, which are limited in time and number, and whose efficiency decreases over time. In other words, the electrical energy storage capacity of current batteries decreases with time and battery use, and after a certain number of cycles, these batteries must be replaced, which generates significant accumulated costs, substantial pollution (production of new batteries), and significant logistical constraints (transport, storage and recycling of used batteries, sometimes complex replacement operations, etc.).

[0010] Today there is a strong need, for practical, ecological and financial reasons, to find a means of easy energy storage that can be used on a massive scale, while being sustainable, clean, and allowing easy storage of all types of energy, particularly so-called renewable energies, especially those with intermittent production such as wind and solar energy, which are particularly difficult to store efficiently, sustainably, cheaply, and without significant environmental impact.

[0011] The objects assigned to the present invention are therefore aimed at remedying the various disadvantages listed above and at proposing a new method of energy storage and release which, while being particularly efficient, is particularly simple to implement, easily repeatable and which has an almost zero, or even zero, carbon footprint at implementation.

[0012] Another object of the invention aims to propose a new method of energy storage and release whose implementation requires only a relatively small space, and which does not involve the use of excessively dangerous and / or expensive materials.

[0013] Another object of the invention aims to propose a new method of storing and releasing energy that is very low polluting, or even non-polluting.

[0014] Another object of the invention aims to propose a new method of energy storage and release whose efficiency remains constant over time, regardless of the number of times it is implemented.

[0015] Another object of the invention aims to propose a new method of energy storage and release allowing energy, in particular electrical energy, to be stored and released in a simple and safe manner, under optimal safety conditions.

[0016] Another object of the invention aims to propose a new method of energy storage and release that is particularly easy to adapt to different energy sources, including renewable energy sources, in particular intermittent or non-intermittent.

[0017] Another object of the invention aims to propose a new method of energy storage and release which is easy to adapt and optimize in terms of the quantity of energy stored desired in relation to the intended use.

[0018] Another object of the invention aims to propose a new method of energy storage and release that is both reliable and economically competitive.

[0019] Another object of the invention aims to propose a new method of energy storage and release whose implementation cost is reduced.

[0020] Another object of the invention aims to propose a new method of energy storage and release involving only a limited number of simple steps.

[0021] Another object of the invention aims to propose a new method of energy storage and release allowing energy to be released in a continuous, regular and / or controlled manner over time, from a random, variable and / or sporadic energy production.

[0022] Another object of the invention aims to propose a new low-polluting or even non-polluting energy storage and release system, easy to implement, particularly durable, and capable of storing energy from different sources, including energy generated intermittently and / or irregularly.

[0023] Another object of the invention aims to propose a new energy storage and release system which is particularly resistant to wear, and whose efficiency is substantially constant over time even if it is subjected to a large number of successive uses.

[0024] Another object of the invention aims to propose a new energy storage and release system allowing for sizing that is as accurate as possible depending on the amount of energy to be stored and its use.

[0025] Another object of the invention aims to propose a new energy storage and release system that is particularly efficient, suitable and compact for storing and releasing quantities of energy, whether on an industrial scale or not.

[0026] Another object of the invention aims to propose a new energy storage and release system of robust design which allows the management of different quantities of energy.

[0027] Another object of the invention aims to propose a new energy storage and release system whose maintenance cost is reduced, and whose maintenance itself is simple and reduced to a strict minimum.

[0028] The objects assigned to the invention are achieved using an energy storage and release process, comprising at least: - a heat transfer step from a first material, which is in a liquid state and comprises at least aluminium and magnesium, to a second material also in a liquid state, said first material being cooled until solidification, the second heated material then passes into a supercritical fluid state. - and a step of transforming the mechanical energy of the second material in the supercritical fluid state into electrical energy.

[0029] The objects assigned to the invention are also reached using an energy storage and release system, comprising at least: - a first material, comprising at least aluminum and magnesium, - a second material, - a heat transfer module, designed to transfer heat from the first material when it is in a liquid state to the second material, also in a liquid state, so that said first material is cooled until solidification, said second material being heated so as to transition to a supercritical fluid state,

[0030] Other features and advantages of the invention will become apparent and will be further detailed upon reading the following description, with reference to the accompanying drawings, given solely by way of illustrative and non-limiting examples, in which:

[0031] [Fig-1] is a schematic illustration of a storage and retrieval process energy of the invention, and of an associated system.

[0032] [Fig.2] is a schematic illustration of a side view of a section of a variant of the energy storage and release system of the invention, compatible with that of [Fig. 1].

[0033] As illustrated in the figures, the invention relates, in a first aspect, to a method for storing and releasing energy. The invention also relates, in a second aspect also illustrated in the figures, to an energy storage and release system 1, preferably designed to operate according to the energy storage and release method mentioned above and described in more detail below. Preferably, the following description concerning the energy storage and release system 1 also applies to the energy storage and release method according to the invention, and vice versa.

[0034] According to the invention, the energy storage and release process comprises at least one heat transfer step Ti from a first material Mi, which is in a liquid state (1) and comprises at least aluminum and magnesium, to a second material M2, also in a liquid state (1), said first material Mi being cooled until solidification (s), said second material M2 thus heated passing into a supercritical fluid state (fs). The notations in parentheses above indicate the state in which the first and second materials Mi, M2 are found at the [Fig. 1], 1 for liquid, s for solid, fc for supercritical fluid. Thus, in other words, at the beginning of said heat transfer step Ti of the first material Mi, the latter is preferably in a liquid state, and more precisely in the state of molten metal, the second material M2 advantageously being in a liquid state. During said heat transfer step Ti of the first material Mi, advantageously, a quantity of heat from the first material Mi (liquid) is transferred to the second material M2 (also liquid), the first material Mi having lost said quantity of heat, thus being cooled at least until its solidification, the second material M2 being heated because it receives said quantity of heat so that it passes, preferably abruptly, from the liquid state to the supercritical fluid state.

[0035] Advantageously, the first and second materials M i5 M 2 are not in direct contact with each other. The heat from the first material M i can optionally be transferred to the second material M 2 via a heat exchanger, or, as will be seen later, via a wall separating the two materials.

[0036] According to a particular embodiment of the invention, the second material M2 is mainly composed of water. Thus, the second material M2 advantageously comprises, by mass, more than 50% water. Preferably, the second material M2 is composed of at least 90% water by mass, and more preferably is composed almost entirely or entirely of water.

[0037] According to the invention, the energy storage and release system 1 comprises at least: - a first material M i, comprising at least aluminium and magnesium, - a second material M2, - a heat transfer module 4, designed to transfer heat from the first material M i when it is in the liquid state to the second material M 2 also in the liquid state, so that said first material M x is cooled until solidification, said second material M 2 being heated so as to pass into the supercritical fluid state.

[0038] Thus, the heat transfer module 4 is advantageously designed to carry out the heat transfer step Ti. The heat transfer module 4 comprises, for example, a container 5, such as a tank, said container 5 being designed to receive the first material Mi, including when the latter is in a liquid state, that is to say, preferably in the form of a molten metal bath. Obviously, said container 5 is also preferably adapted to receive the first material Mi in a solid state. Indeed, advantageously, in system 1 and in the energy storage and release process, the first material Mx remains within said container 5 for its phase change(s) (liquid to solid, or, as we will see later, solid to liquid). There is no preference for significant displacement of the first material MA when it is within the heat transfer module 4 (unlike the second material M2).

[0039] Particularly advantageously, said first material M i comprises at least, by mass proportion, between 62% and 95% aluminum and between 5% and 38% magnesium, preferably between 62% and 88% aluminum and between 12% and 38% magnesium, more preferably between 62% and 83% aluminum and between 17% and 38% magnesium. This allows for an excellent compromise between cost, thermal energy storage capacity, and liquid / solid phase change temperature.

[0040] The first material M x advantageously beginning to melt at a temperature between approximately 450 °C (+ / - 3°C) and approximately 600 °C (+ / - 3°C), preferably at a temperature between approximately 450 °C (+ / - 3°C) and approximately 500 °C (+ / - 3°C), more preferably at a temperature approximately equal to 450 °C (+ / - 3°C).

[0041] According to the invention, the process includes a step of transforming the mechanical energy of the second material M2 in the supercritical fluid state into electrical energy E. In fact, preferably, the second material M2, which was in the liquid state, passes, under the effect of the heat received from the first material M1, into the supercritical fluid state, which advantageously has a high pressure and temperature (compared to the second material M2 in the liquid state), which advantageously allows the generation of mechanical energy which can be transformed into electrical energy E.

[0042] According to a particular embodiment, the energy transformation step T Ê is carried out using one or more turbine(s) 6. The energy transformation step T Ê is more particularly carried out using one or more generator(s) 7, said generator 7 being advantageously connected to said turbine 6, which is thus preferably driven by the second material M 2 in the supercritical fluid state, and more specifically by the mechanical work generated by the latter.

[0043] According to the invention, the energy storage and release system 1 comprises a transformation module 8 of the mechanical energy of the second material M 2 in the supercritical fluid state into electrical energy E Ê. Said transformation module 8 is thus advantageously intended to carry out the energy transformation step T s.

[0044] Said transformation module 8 comprises, for example, one or more turbines 6. Advantageously, said transformation module 8 comprises one or more generators 7, said generator 7 being advantageously connected to said turbine 6. More specifically, the system 1 is advantageously designed, and the process is advantageously provided, so that the second material M2 is set in motion When it transitions from a liquid to a supercritical fluid state during the heat transfer step Te, within the heat transfer module 4, particularly due to the high pressure of the second material M2 in its supercritical fluid state, the movement of the second material M2 in its supercritical fluid state represents a certain amount of mechanical energy. This movement of the second material M2 advantageously drives the actuation of the turbine 6 and the generation, via the generator 7 connected to the turbine 6, of electrical energy Ee during the energy transformation step Te, within the heat transfer module 4. It is, in a sense, the expansion of the second material M2 in its supercritical fluid form that allows for the generation of mechanical energy, which is ultimately obtained from the heat transfer from the first material T1 to the second material T2.In a particularly advantageous way, the second material M2 passes from the liquid state to the supercritical fluid state due, on the one hand, to the significant rise in its temperature due to the heat received from said first material Mx, and on the other hand to the fact that said second material M2 is preferentially placed within a finite space, delimited by walls, for example a conduit 3, this resulting, along with the rise in temperature, in a rise in pressure in the finite space occupied by the second material M2.

[0045] Optionally, the system 1 includes several turbines 6 in series designed to recover the mechanical energy of the second material M 2 in the supercritical fluid state.

[0046] Advantageously, said second material M2 in the supercritical fluid state has a pressure greater than or equal to 100 bar, preferably greater than or equal to 200 bar, and more preferably greater than or equal to 300 bar. Preferably, said second material M2 in the supercritical fluid state has a temperature greater than or equal to 200°C, preferably greater than or equal to 300°C, and more preferably greater than or equal to 400°C. For example, when the second material M2 is composed of water (almost entirely or entirely), the supercritical fluid state is reached at a temperature greater than approximately 374°C (referred to as the critical temperature) and at a pressure greater than approximately 221 bar (referred to as the critical pressure).The second material M2 may optionally be formed from a component other than water, preferably having a critical temperature and critical pressure substantially of the same order of magnitude as those of water.

[0047] According to a variant of the invention, the heat transfer module 4 comprises one or more conduits 3 containing the second material M2 in a liquid state. Thus, during said heat transfer step T, the second material M2 in a liquid state is located within a conduit 3. Thus, said first and second materials M15 M 2 are preferably separated from each other by the wall of said conduit 3, which wall transmits heat from the first material Mi (in the liquid state) to the second material M2 (in the liquid state). Said conduit 3 is advantageously immersed within the first material Mh and is in particular positioned within said container 5. For example, the first material Mi forms, before and / or at the beginning of said heat transfer step Te, a metallic bath (i.e., a quantity of molten metal Mg / Al) 2 in which the conduit (metallic, ceramic, or any other suitable material) 3 is immersed, collecting the second material M2 in the liquid state during said heat transfer step Te. The conduit 3 opens, for example, onto the turbine(s) 6.

[0048] Preferably, the energy storage and release process further comprises, prior to said heat transfer step T1, a heating step C of said first material M2 in the solid state until melting. The heating step C is preferably carried out by means of resistive heating, as illustrated in [Fig. 2], and / or induction heating. Thus, advantageously, the system 1 also comprises a heating means 9 for said first material M1 in the solid state until melting. Said heating means 9 is preferably a resistive heating means, as illustrated in [Fig. 2], and / or an induction heating means. The heating means 9, if resistive, comprises, for example, one or more resistors embedded within the first material M1, said resistor therefore preferably being positioned in the container 5, as illustrated in [Fig. 2].The heating means 9, if it is by induction, is preferably placed outside the container 5, without direct contact with the first material M i5 and comprises for example a coil wound around said container 5, the walls of the latter being preferably non-ferromagnetic.

[0049] The first material M x is therefore advantageously liquefied by raising its temperature during said heating step Ç, using the heating means 9, so as to form, for example, a metallic bath which can be homogeneous, the formation of the metallic bath preferably starting at a temperature in the range of 450 to 600°C. The presence of magnesium and aluminum in the first material allows the metal bath (i.e., the first material in the liquid state) to store a significant amount of energy while having a relatively low melting point (which begins at a temperature between 450 and 600°C, more preferably around 450°C), this melting point being easily reached by modern ovens (for example, kitchen ovens, generally via a so-called "pyrolysis" cleaning function, at around 500°C).Such a configuration facilitates the design of system 1 and the implementation of the method of the invention.

[0050] According to a particular embodiment, the energy storage and release process further comprises a renewable energy production step Ps. According to this latter embodiment, the heating step C is carried out at least partly using said renewable energy. This renewable energy production step Pg is, in a particular variant, carried out using an intermittent renewable energy source, such as solar and / or wind energy. The system 1 then advantageously comprises a renewable energy production module 10, which operates, for example, using an intermittent renewable energy source, such as solar and / or wind energy.The renewable energy production module 10 is thus advantageously formed by an electrical energy production device, from, for example, a wind, solar, tidal, wave, hydroelectric, biomass, etc. energy source. The renewable energy production module 10 comprises, according to a first example, one or more wind turbines 10, as illustrated in [Fig. 1], and / or, according to another example, one or more solar panels.The advantage of such a configuration, in which, in substance, the heating energy is supplied preferably mainly using a renewable energy source, is that it allows both the accumulation, and therefore the storage, of the electrical energy produced by the renewable energy production module 10, in thermal form (the molten metal bath constituted by the first material M i in the liquid state), while controlling the moment of the energy release in electrical form, that is to say the moment when the heat transfer step T £ (then said transformation step T s) is carried out.

[0051] The process and system 1 thus make it possible, in particular, to "smooth"—that is, to make stable and / or controllable over time—a given energy production, advantageously renewable and intermittent, thanks to, on the one hand, the formation of a "buffer" stock of thermal energy in the form of an aluminum / magnesium metallic bath formed in practice by the first material Mi in its liquid state, and on the other hand, the timely transfer of heat from the first material MA to the second material M2, which in practice releases mechanical energy, itself finally transformed into electrical energy EE. Thus, according to a particular embodiment, said process and system 1 are intended to enable the management of energy produced using renewable energy (or possibly another source), for example, intermittent production.Indeed, for obvious economic reasons of risk of shortage and ecological reasons linked to pollution, particularly carbon pollution, research is currently being carried out to replace at least part of the so-called "non-renewable" energy sources with sources. of so-called "renewable" energy, that is to say, which nature renews relatively quickly on a human timescale, and which also have a much less polluting exploitation, but often intermittent.

[0052] The heat transfer step Te includes, for example, introducing the second material M2 in a liquid state into said conduit 3, for example by means of a pump 11. Under the effect of the heat transferred through the wall of the conduit 3 and originating from the first material Mi in a liquid state, the second material M2 thus advantageously changes abruptly into a supercritical fluid state, and can drive, preferably outside the container 5, the turbine 6, thereby releasing its mechanical energy, which can be converted into electrical energy Es by the generator 7. The heat transfer module 4 thus advantageously includes a means for introducing the second material M2 in a liquid state into said conduit 3, said means for introducing including, for example, a pump 11.

[0053] The initiation of the heat transfer step Te can be determined by a predetermined parameter, for example, a signal indicating a demand for energy supply. Thus, the process advantageously comprises, prior to said heat transfer step Te, the emission of a signal, said signal triggering said heat transfer step Te. The system 1 is therefore preferably designed to emit and / or receive a signal triggering the heat transfer from the first material Mi in the liquid state to the second material M2 in the liquid state, within the heat transfer module 4. The heat transfer from the first material Mi in the liquid state to the second material M2 in the liquid state is therefore preferably carried out in a controlled manner.System 1 and the method of the invention thus allow the accumulation of thermal energy from electrical energy from a renewable source, and then the release of electrical energy Ei at a chosen time from the accumulated thermal energy. Indeed, the first material Mi in a liquid state, for example in the form of a metallic bath contained in the container 5, can be kept for a certain time without solidifying due to heat losses, in particular if said container 5 is well thermally insulated. This configuration makes system 1 and the method particularly suitable for certain uses, such as the controlled supply of electricity and / or heat to a building 12 or even to an electrical network. For example, the electrical energy Ei produced by the transformation module 8 can supply a building 12, as illustrated in [Fig.l], and more specifically the heating system of the latter and / or the hot water heating system of said building 12. .

[0054] According to a particular embodiment, the process comprises, after said transformation step T, a cooling step R of said second material M2 to the liquid state. The process further advantageously includes a further heat transfer step from the first material M1 in the liquid state to the second material M2, which has returned to the liquid state (during said cooling step R), in order to cool said first material M1 to solidification and heat said second material M2 to the supercritical fluid state. In other words, the process is advantageously designed to operate cyclically, with the first material M1 and the second material M2 being reused in a plurality of cycles, each cycle successively comprising at least the heating step C, heat transfer step T1, energy transformation step T2, and cooling step R.According to this particular embodiment, system 1 thus comprises a means for cooling the second material M2, positioned for example downstream of the turbine 6, designed to cool the second material M2 (generally in a gaseous state at that point) to a liquid state. System 1 is then advantageously designed to reintroduce the second material M2, cooled to a liquid state, into the heat transfer module 4.

[0055] The energy storage and release process advantageously comprises, after said transformation step TE, a heat transfer step T2 from the second material M2 to a heating system, for example, a building heating system 12 and / or a hot water heating system (which may be that of said building 12). The energy storage and release system 1 thus preferably comprises, downstream of the transformation module 8, a means for transferring heat from the second material M2 to a heating system, for example, a building heating system 12 and / or a hot water heating system (which may be that of said building 12).

[0056] Advantageously, the cooling stage R and the heat transfer stage T2 of the second material M2 are at least partially combined, the heat transfer T2 from the second material M2 to the heating system obviously lowering the temperature of the second material M2. Thus, preferably, the cooling means and the heat transfer means of the second material M2 include at least one common device, for example a heat exchanger 13. Optionally, the second material M2 is used directly to supply heat to a building, for example for a hot water central heating system for a building 12 or, more optionally, to supply usable hot water for the occupants of said building 12.

[0057] In summary, the invention relates to energy storage issues, the management of renewable energies including those with intermittent production, and aims in particular to optimize the management of electricity produced by power plants facing fluctuating grid demands. The invention also addresses local electrical energy storage needs, for example to enable substantial energy savings in condominium, industrial or commercial buildings, which can thus become partially energy self-sufficient thanks to the process and system 1 of the invention.

Claims

Demands

1. A method for storing and releasing energy, comprising at least: - a heat transfer step (Tc) from a first material (MJ), which is in the liquid state and comprises at least aluminium and magnesium, to a second material (M2) also in the liquid state, said first material (MJ) being cooled until solidification, said second material (M2) thus heated passing into the supercritical fluid state, - and a transformation step (Te) of the mechanical energy of the second material (M2) in the supercritical fluid state into electrical energy (Ee).

2. Energy storage and release method according to the preceding claim, characterized in that it comprises, prior to said heat transfer step (Tc), a heating step (C) of said first material (MJ) in the solid state until melting.

3. Energy storage and release method according to the preceding claim, characterized in that the heating step (C) is carried out by means of resistive heating and / or induction heating.

4. Energy storage and release method according to claim 2 or 3, characterized in that it further comprises a renewable energy production step (Pe), and in that the heating step (C) is carried out at least in part using said renewable energy.

5. Energy storage and release method according to the preceding claim, characterized in that said renewable energy production step (Pe) is carried out using an intermittent renewable energy source, such as solar and / or wind energy.

6. A method for storing and releasing energy according to any one of the preceding claims, characterized in that said first material (MJ) comprises at least, by mass proportion, between 62% and 95% aluminum and between 5% and 38% magnesium, preferably between 62% and 88% aluminum and between 12% and 38% magnesium, more preferentially between 62% and 83% aluminium and between 17% and 38% magnesium.

7. A method for storing and releasing energy according to any one of the preceding claims, characterized in that said second material (M2) is mainly formed of water, preferably is formed at least 90% by mass of water, and more preferably is formed almost entirely or entirely of water.

8. A method for storing and releasing energy according to any one of the preceding claims, characterized in that it comprises, after said transformation step, a cooling step (R) of said second material (M2) to the liquid state, and a further heat transfer step from first material (Mi) in the liquid state to second material (M2) returned to the liquid state, in order to cool said first material (Mi) to solidification and heat said second material (M2) to the supercritical fluid state.

9. A method for storing and releasing energy according to any one of the preceding claims, characterized in that it comprises, after said transformation step (Te), a heat transfer step (T2) from the second material (M2) to a heating system, for example a building heating system (12) and / or a hot water heating system.

10. Energy storage and release method according to any one of the preceding claims, characterized in that said second material (M2) in the supercritical fluid state has a pressure greater than or equal to 100 bars, preferably greater than or equal to 200 bars, more preferably greater than or equal to 300 bars.

11. A method for storing and releasing energy according to any one of the preceding claims, characterized in that said energy transformation step (Te) is carried out using one or more turbine(s) (6).

12. Energy storage and release system (1), comprising at least: - a first material (Mi), comprising at least aluminium and magnesium, - a second material (M2), a heat transfer module (4), designed to transfer heat from the first material (MJ) when it is in the liquid state to the second material (M2) also in the liquid state, so that said first material (MJ) is cooled until solidification, said second material (M2) being heated so as to pass into the supercritical fluid state, and a transformation module (8) of the mechanical energy of the second material (M2) in the supercritical fluid state into electrical energy (Ee).

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