WO2019105735A1

WO2019105735A1 - System and method for heat storage and release, with a collar

Info

Publication number: WO2019105735A1
Application number: PCT/EP2018/081172
Authority: WO
Inventors: Cecile Plais; Pierre BALZ; Stéphane Poncet; Elena Sanz; Guillaume Vinay
Original assignee: IFP Energies Nouvelles
Priority date: 2017-11-28
Filing date: 2018-11-14
Publication date: 2019-06-06
Also published as: CN111448439A; FR3074276A1; FR3074276B1; EP3717854A1; US20200386491A1

Abstract

The invention relates to a system and a method for heat storage and recovery, comprising at least one fixed bed (2) of storage particles. The fixed bed (2) of particles comprises an obstacle (4), for example a collar, arranged on the periphery of the fixed bed (2) of storage particles, and substantially perpendicularly to the circulation flow (3) of said fluid. The invention also relates to a system and a method for energy storage and recovery using the heat storage and recovery system and method.

Description

SYSTEM AND METHOD FOR HEAT STORAGE AND RESTITUTION WITH FLANGE

The present invention relates to the field of energy storage by compressed gas, including air (CAES Compressed Air Energy Storage). In particular, the present invention relates to an AACAES (Advanced Adiabatic Compressed Air Energy Storage) system in which the storage of the gas and the storage of the heat generated are provided.

In a compressed air energy storage system (CAES), energy, which is to be used at another time, is stored as compressed air. For storage, energy, especially electrical, drives air compressors, and for destocking, the compressed air drives turbines, which can be connected to an electric generator. The efficiency of this solution is not optimal because part of the energy of the compressed air is in the form of heat which is not used. In fact, in the CAES processes, only the mechanical energy of the air is used, that is to say that all the heat produced during the compression is rejected. For example, compressed air at 8 MPa (80 bar) heats during compression to about 150 ° C, but is cooled prior to storage. In addition, the system requires heating the stored air to achieve the relaxation of the air. Indeed, if the air is stored at 8 MPa (80 bar) and at room temperature and if it is desired to recover the energy by a relaxation, the decompression of the air again follows an isentropic curve, but this time from the initial storage conditions (about 8 MPa and 300 K). The air is cooled to unrealistic temperatures (83 K or -191 ° C). It is therefore necessary to heat it, which can be done using a gas burner, or other fuel.

Several variants currently exist for this system. Systems and methods include:

• ACAES (Adiabatic Compressed Air Energy Storage) in which air is stored at high temperature due to compression. However, this type of system requires a specific storage system (adiabatic storage), bulky and expensive.

• AACAES (Advanced Adiabatic Compressed Air Energy Storage) in which air is stored at room temperature, and the heat due to compression is also stored separately in a TES heat storage system. "Thermal Energy Storage"). The heat stored in the TES is used to heat the air before it is released. A first solution envisaged for the TES heat storage system is the use of a heat transfer fluid for storing the heat resulting from the compression to return it to air before expansion by means of heat exchangers. For example, patent application EP 2447501 describes an AACAES system in which oil, used as heat transfer fluid circulates in closed circuit to exchange heat with air. Moreover, the patent applications EP 2530283 and WO 201 105341 1 describe an AACAES system, in which the heat exchanges are carried out by a coolant circulating in a closed circuit, the closed circuit comprising a single heat transfer fluid reservoir.

However, the systems described in these patent applications require specific means of storage and circulation of the coolant. In addition, for these systems, significant pressure losses are generated by the heat exchangers used.

A second solution envisaged for the TES heat storage system is based on a static storage of heat (without moving the bed of heat storage particles or heat transfer fluid). In this case, the heat storage means may be made with one or more fixed bed (s) of heat storage particles. During charging, the hot compressed gas passes through the heat storage means. By heat exchange between this gas and the storage particles, they are heated and the compressed gas is cooled. In the same way, during the discharge, the heat exchange generated between the storage particles and the compressed gas, cools the storage particles and warms the compressed gas. The fixed bed of storage particles is generally maintained in the storage means, by a holding structure, which may be directly the wall of the storage means, or a structure mounted inside the storage means. During the charging or discharging of the heat storage system, the temperature of the fixed bed in a plane orthogonal to the flow of the compressed gas is substantially homogeneous, except near the holding structure. In fact, the proximity of the wall induces, in the granular structure of the medium, a particular arrangement of the particles at the wall (edge effect). This particular arrangement affects the velocity profile of the gas flows at the wall and therefore the temperature profile of the particles.

As a result, the thermal gradient, along a section orthogonal to the flow of the compressed gas, is zero, or almost nil, except at the level of the holding structure, juxtaposed with the fixed bed, at the periphery of the fixed bed: this indicates that the temperature is homogeneous or almost homogeneous in this section, orthogonal to the axis of the gas flow compressed, except at the periphery of the fixed bed, at the level of the holding structure. This heterogeneity of the temperature profile in the fixed bed induces a loss of the overall efficiency of the storage means and a loss of overall performance of the system.

To overcome these drawbacks, and in particular to limit the loss of efficiency related to edge effects, the present invention relates to a means of storing heat consisting of at least one fixed bed of heat storage particles. Inside the storage means, at least one obstacle orthogonal or substantially orthogonal to the air flow is positioned at the periphery of the bed of storage particles. This obstacle is distributed along the periphery of the fixed bed (continuously or discontinuously). It makes it possible to locally remove the flow of compressed gas from the end of the fixed bed of particles, and thus from the holding structure juxtaposing the fixed bed, thereby reducing the edge effect by the holding structure.

The method and the system according to the invention

The invention relates to a system for storing and recovering heat comprising at least one storage chamber, at least one fixed bed of storage and heat recovery particles being placed in said storage chamber and at least one fluid which can circulating through said fixed bed in said storage enclosure, said storage enclosure comprising at least one inlet of said fluid in said storage enclosure and at least one outlet of said fluid from said storage enclosure, characterized in that at least one obstacle is positioned in said fixed bed, substantially perpendicular to the flow of circulation of said fluid, said obstacle being positioned at the periphery of said fixed bed of said particles for storing and recovering heat, said obstacle being distributed around the perimeter of said fixed bed said storage particles.

According to a variant of the invention, the system comprises at least two regularly spaced obstacles along said circulation flow of said fluid.

Preferably, the spacing between two successive obstacles following said flow of circulation of said fluid is at least twice the size of said obstacle, perpendicular to said flow of said fluid flow.

According to one embodiment of the invention, said storage chamber comprises at least one distributor for dispensing said fluid into said fixed bed, and preferably at least two distributors.

Preferably, said obstacle is positioned at said distributor.

According to one embodiment, said obstacle consists of a plate.

Advantageously, the dimension of said obstacle, perpendicular to said circulation flow of said fluid, is between 1 and 10 times the Sauter equivalent diameter of said storage and heat recovery particles of said fixed bed, preferably between 3 and 5 times the Sauter equivalent diameter of said particles for storing and recovering heat from said fixed bed.

According to one embodiment, said storage enclosure is cylindrical or substantially cylindrical.

According to an alternative embodiment, said circulation flow of said fluid inside said storage enclosure is along the axis of said storage enclosure.

Advantageously, said obstacle consists of an annular plate disposed on the internal face of the cylindrical wall of said storage enclosure.

According to another variant embodiment, said circulating flow of said fluid inside said storage enclosure is along an axis perpendicular to the axis of said storage enclosure, at least two support trays of said fixed bed being positioned at inside said storage enclosure, said support trays being perpendicular to the axis of said storage enclosure.

Advantageously, said obstacle is positioned on said support plates, said obstacle then forming a piece of cylinder on each of the two support plates of said fixed bed of said particles for storing and recovering heat.

According to one embodiment, said obstacle is distributed continuously over the periphery of the periphery of said fixed bed.

Alternatively, said obstacle is distributed discontinuously around the perimeter of said fixed bed.

The invention also relates to a system for storage and energy recovery by compressed gas comprising at least one gas compression means, at least one compressed gas storage means, at least one expansion means of said compressed gas to generate a compressed gas energy, and at least one means for storing heat according to one of the preceding characteristics.

The invention also relates to a method for storing and recovering heat, in which the following steps are carried out:

a) The heat is stored in a fixed bed of storage and heat recovery particles, by circulating a fluid in said fixed bed; and

b) The heat recovered by said fixed bed is returned by circulating a fluid in said fixed bed.

For storing and returning heat, said fluid is subjected to at least one obstacle positioned in the fixed bed, perpendicularly or substantially perpendicular to the flow of said fluid, said obstacle being positioned at the periphery of said fixed bed of said particles for storing and recovering heat, said obstacle being distributed around the perimeter of said fixed bed of said particles for storing and recovering heat,

According to a variant of the invention, said fluid passes through a stepped arrangement formed by a plurality of said fixed beds contained in said means for storing and recovering heat.

According to one embodiment, said means for storing and restoring the heat is of substantially cylindrical shape.

According to a variant, said fluid passes radially through said fixed bed of said means for storing and recovering heat.

Alternatively, said fluid passes axially through said fixed bed of said means for storing and returning heat.

The invention also relates to a method for storage and energy recovery by compressed gas, in which the following steps are carried out:

a) compressing a gas;

b) said compressed gas is cooled by heat exchange with a fixed bed of particles for storing and recovering heat;

c) storing said cooled gas;

d) heating said cooled compressed gas by restoring the heat of said fixed bed of said storage particles and heat recovery; and

e) said heated compressed gas is expanded to generate energy.

for which the storage and the return of the heat are carried out according to the method of storing and restoring the heat according to one of the preceding characteristics.

Brief presentation of the figures

Other features and advantages of the system and method according to the invention will become apparent on reading the following description of nonlimiting examples of embodiments, with reference to the appended figures and described below.

FIG. 1 illustrates a system for storing and recovering heat according to one embodiment of the invention.

FIG. 2 illustrates a system for storing and recovering heat according to a second embodiment of the invention.

FIG. 3 illustrates a system for storing and recovering heat according to a third embodiment of the invention. FIG. 4 illustrates a system for storing and recovering heat according to a fourth embodiment of the invention.

FIG. 5 illustrates the distribution of the temperatures in a plane perpendicular to the direction of the circulation of the fluid according to a system for storing and recovering the heat of the prior art.

FIG. 6 shows a comparison of the evolution of temperatures over time for two diametrically opposite points of two storage and heat recovery systems, a first according to the prior art and a second according to the invention.

FIG. 7 illustrates a compressed gas storage and energy recovery system according to the invention.

Detailed description of the invention

The present invention relates to a system for storing and recovering heat. In this implementation, a fluid (for example a compressed gas) circulates through a fixed bed of storage and heat recovery particles, allowing a heat exchange between the fluid and the particles. The particles are chosen from a material capable of storing and returning heat.

The system according to the invention comprises:

- At least one storage enclosure;

At least one fluid circulating in the storage enclosure;

- At least one fixed bed of particles of storage and return of heat. These solid particles, hereinafter referred to as "storage particles", exchange heat with the fluid during the storage and heat recovery phases, the heat being stored in the particles between these two phases. According to the invention, the heat storage particles are distributed over at least one fixed bed. A fixed bed is an arrangement of heat storage particles in which the particles are immobile. The heat storage particles allow the passage of gas in the fixed bed;

- At least two fluid inlet / outlet at the storage chamber, knowing that the direction of the flow is reversed between the storage operations and the return of heat. Preferably, the input / output may be located at ends remote from the fixed bed.

At least one obstacle positioned in the fixed bed, perpendicularly or substantially perpendicularly to the flow of fluid flow, at the periphery of the fixed bed of storage particles, the obstacle being distributed around the perimeter of the fixed bed, in such a way as to continuous or discontinuous. By obstacle positioned perpendicularly or substantially perpendicularly to the fluid flow, it is meant that the main plane of the obstacle (for example, plane of the plate in the case of a plate or an annular plate) is orthogonal or substantially orthogonal to the fluid flow

o The obstacle is positioned at the periphery of the fixed bed of the storage particles: when the fixed bed is delimited by walls, for example the walls of the storage enclosure or fixed bed support plates, the obstacle can positioned in contact with the wall of the storage chamber or in contact with the support plates positioned at the periphery of the fixed bed.

By obstacle distributed around the perimeter of the fixed bed, it is meant that the profile of the obstacle is reproduced over a major part of the periphery of the fixed bed, preferably substantially the entire periphery of the fixed bed. For example, for a cylindrical enclosure, it may be represented by an annular plate (obstacle distributed continuously) or by an annular plate with holes (obstacle distributed in a continuous manner), possibly evenly distributed on the plate, or by a a multitude of small plates distributed regularly (obstacle distributed discontinuously) on the entire inner cylinder of the enclosure. The presence of this obstacle makes it possible locally to move the fluid away from the periphery of the fixed bed, thus improving the homogeneity of the temperature inside the fixed bed of particles, and therefore the overall efficiency of the installation. Indeed, a temperature profile in a plane perpendicular to the flow of fluid flow more homogeneous resulting in a better heat exchange between the fluid and the fixed bed of storage particles. As a result, the overall performance of the storage system is improved. Furthermore, the nature of the obstacle does not cause a significant increase in pressure losses and therefore does not impact the overall operation of the storage system and heat recovery.

Each fixed bed may comprise solid particles or particles containing a phase change material (PCM). For this, the particles may be in the form of capsules containing PCM. The use of particulate bed containing MCP allows better control of the thermal gradient in the tank, through the use of different melting temperatures. A compromise between efficiency and cost can also be found in mixing PCM and storage materials by sensible heat in the same bed. Among the phase-change materials, the following materials may be used: paraffins, whose melting point is less than 130 ° C, salts which melt at temperatures above 300 ° C, (eutectic) mixtures which allow to have a wide range of melting temperature.

The solid particles (whether or not with a phase change) may have all the known forms of conventional granular media (beads, cylinders, extrusions, trilobes, etc.), as well as any other shape that maximizes the surface area. exchange with gas. The particle size may vary between 0.5 mm and 10 cm, preferably between 2 and 50 mm and even more preferably between 5 and 20 mm.

The temperature range over which the heat storage means can operate is between 0 ° and 500 ° C, more preferably between 100 and 400 ° C, and even more preferably between 100 and 350 ° C. The temperature levels depend both on the complete AACAES process and the type of material used for the particles of the heat storage means.

According to one embodiment of the invention, the system may comprise at least two regularly spaced obstacles along the flow of fluid flow. The presence of these regularly spaced obstacles improves the homogeneity of the temperatures and thus the performance. For example, the obstacles can be positioned at the input / output levels of the fixed bed and / or in the middle and preferably at the entrance, middle and exit of the fixed bed. This configuration allows optimized distribution of heat flow in the fixed bed.

According to an alternative embodiment of the invention, the spacing between the two successive obstacles may be at least equal to twice the dimension of the obstacle perpendicular to the flow of traffic. Indeed, respecting this minimum spacing, the flow that is locally deflected by the obstacle to the center of the fixed bed of particles can again approach the walls of the bed before encountering the next obstacle. Thus, the gas flow approaching the next obstacle is very close to the one he would see if the previous obstacle did not exist.

According to an alternative embodiment of the invention, the storage enclosure may comprise at least one distributor. The term "distributor" means a device that distributes the fluid as homogeneously as possible in the fixed bed of storage particles, so as to optimize the heat exchange between the fluid and the fixed bed of storage particles. Preferably, at least two distributors can be put in place, the first at one end of the fixed bed of storage particles and the second at the other end of the fixed bed of storage particles For example, when the fluid circulates in a direction of circulation (for example during charging), the first distributor can be placed at the entrance of the fixed bed of storage particles, just before the fluid enters the fixed bed of storage particles and the second at the outlet of the fixed bed of storage particles, just after the exit of the fluid from the fixed bed of storage particles. In the case where the fluid flows to the discharge, in the opposite direction of circulation, the second distributor is then found at the entrance of the gas in the fixed bed of storage particles, just before the fluid enters the fixed bed storage particles, and the first distributor is then found at the gas outlet of the fixed bed of storage particles, just after the output of the fixed bed of storage particles. Alternatively, other dispensers may be added and positioned within the fixed bed of storage particles.

According to one embodiment of the invention, the obstacle can be positioned at the distributor. Thus, the local acceleration and the movement of the gas flow by synergy between the presence of the obstacle and that of the distributor, are improved.

According to one embodiment of the invention, the obstacle may consist of a plate. This design allows a simple and inexpensive manufacture of the obstacle. Furthermore, the plate does not need to be mechanically fixed, which simplifies its implementation and makes the invention usable in the modernization or remodeling of an installation. In this case, the plate is placed on the fixed bed of particles.

According to one characteristic of the invention, the dimension of the obstacle perpendicular to the flow of the fluid flow may be equal to a value between 1 and 10 times the Sauter equivalent diameter of the storage particles, preferably between 3 and 5 times the equivalent diameter of Sauter storage particles. Sauter equivalent diameter is the characteristic quantity of the storage particles d ₃₂ defined by: d ₃₂ = 6 - Ap with V _p the volume of the particles and A _p the particle area. This characteristic of the invention makes it possible to limit the loss of charge induced by the obstacle while optimizing the effect of the presence of the obstacle on the evolution of temperatures in a plane perpendicular to the flow of fluid circulation.

According to one embodiment of the invention, the storage chamber may be cylindrical or substantially cylindrical.

In addition, the flow of fluid flow inside the storage chamber, cylindrical or substantially cylindrical, can be done along the axis of the storage chamber. We then speak of "axial flow" to designate this mode of circulation of the fluid inside the storage enclosure and "axial flow system" to designate a system for storing and recovering heat with a mode of flow of fluid with axial flow.

Moreover, the obstacle in the cylindrical or substantially cylindrical storage chamber may be an annular plate. This type of obstacle is simple to manufacture, inexpensive and responds well to the desired problem of local distance of the flow of fluid flow from the periphery of the fixed bed.

Alternatively, the circulation flow of the fluid inside the storage chamber, cylindrical or substantially cylindrical, can be done along an axis perpendicular to the axis of the storage enclosure. In this case, one speaks of "radial flow" for the circulation of the fluid inside the storage enclosure and "system with radial flow" to designate a system of storage and restitution of the heat with a mode of circulation of the radial flow fluid. To do so, trays called "support trays" can be used and positioned inside the storage enclosure. They serve to maintain the fixed beds of storage particles and to direct the fluid flow flow, in the radial direction, inside the storage enclosure.

In the radial flow system, the obstacle can be positioned on the support plates. The obstacle is then divided into two parts, a first part positioned on the so-called "upper" support plate and a second part on the "lower" support plate. On each of these two support plates, the obstacle represents for example a piece of cylinder.

According to one embodiment, the obstacle can be distributed in a continuous manner around the perimeter of the fixed bed, for example, by a plate or a collar. This allows the use of a simple form to manufacture.

Alternatively, the obstacle can be distributed discontinuously around the perimeter of the fixed bed, for example by several obstacles, distributed around the periphery. This has the advantage of having several smaller size elements, more easily transportable, and for which the introduction and positioning in the storage means is easier.

FIGS. 1 to 3 show non-limiting examples of embodiments of a system for storing and recovering axial flow heat according to the invention.

FIG. 1 represents, schematically and in a nonlimiting manner, heat storage and recovery means 10 equipped with a storage chamber 1, a fixed bed 2 of storage particles, a fluid whose circulation 3 is shown by arrows. In storage mode, the circulation of the fluid is via an inlet 8 of the fluid in the storage enclosure 1 to an outlet 9 of the storage enclosure 1. In the restitution mode, the circulation of the fluid 3 can be reversed in the storage chamber 1: the fluid then enters through the inlet 9 and leaves the outlet 8. The storage enclosure 1 comprises two distributors 5 and an obstacle 4 positioned at the periphery of the fixed bed 2, the obstacle 4 being perpendicular to the flow flow 3 of the fluid, the obstacle 4 is also distributed and continuous on the periphery of the fixed bed 2 and positioned at the periphery of the fixed bed 2. In the example of Figure 1, the obstacle 4 is an annular plate. Alternatively, other forms of obstacles can be used.

FIG. 2 shows, schematically and in a nonlimiting manner, an alternative embodiment in which two obstacles 4 are put in place in the storage enclosure 1, at the periphery of the fixed bed 2, perpendicular to the flow of circulation 3. These two obstacles are continuous around the perimeter of the fixed bed 2. The characteristic dimension of the obstacle 4, perpendicular to the flow of circulation 3 of the fluid 3 is indicated by the letter L. For example, for an obstacle 4 which would have the form of An annular plate as in Figure 2, L corresponds to the width of the annular plate. The spacing between two successive obstacles 4, is materialized by the distance E, in the direction of the flow of circulation 3. Preferably, the dimension L may be equal to a value between 1 and 10 times the equivalent diameter of Sauter particles storage, preferably between 3 and 5 times the Sauter equivalent diameter of the storage particles. Also preferably, the spacing E may be at least twice the dimension L of the obstacle, perpendicular to the flow of traffic.

FIG. 3 shows, schematically and in a nonlimiting manner, an example of an embodiment variant of the invention in which several obstacles are used, in particular an obstacle 4 is positioned at the level of the inlet and outlet distributors 5. Alternatively, obstacle 4 can also be positioned at one or other of the inlet or outlet distributors 5 or alternatively on an intermediate distributor, which would be positioned inside the fixed bed 2 (not shown). Figure 3 also shows an obstacle positioned at a level where no distributor is present.

In FIG. 4, schematically and in a nonlimiting manner, a radial flow heat storage and return system 20 is shown. In this example, the system comprises 6 layers of fixed beds 2, each layer having an annular section. In storage mode, the fluid enters through the inlet 8 in the storage enclosure. In heat recovery mode, fluid flow can be reversed. Then the flow of traffic, materialized by the arrows, is directed by the support plates 6 which alternately directs the flow from the center of the enclosure to the outside or from outside the enclosure to the center, depending on the number and position of the fixed bed 2. The right-hand part of Figure 4 shows, for example, two different ways to position the obstacles 4 in this radial flow system 20. The diagram at the top right shows two obstacles 4 positioned at the level of the distributors 5 at the entrance and the exit of each fixed bed 2. The diagram at the bottom right shows an obstacle 4 positioned at about half the width of the fixed bed 2, that is to say equidistant from the two inlet and outlet distributors 5 of each fixed bed 2. It is noted that for the two diagrams of the right part, the obstacle 4 is divided into two parts, each of the parts being a cylindrical wall axis coinciding with the axis of the storage enclosure, an upper portion positioned at the top of the fixed bed 2, near the plateau of support 6 said upper and lower part at the bottom of the bed fi xe 2, near the support plate 6 said lower. These examples are not limiting: other numbers of obstacles, other positions of obstacles and other forms of obstacles can be envisaged.

FIG. 5 shows the temperature iso-contours at a time t during the storage of heat in a fixed bed of storage particles for a heat storage and recovery system according to the prior art, that is to say to say without obstacle. The shades of gray in Figure 5 indicate temperature changes. The evolution of the temperature front 25 in a plane orthogonal to the flow flow 3 of the fluid illustrates:

that the temperature front is almost constant in a plane orthogonal to the flow flow 3 of the fluid, when positioned near the center of the fixed bed.

that local evolutions of temperatures 7 are obtained near the periphery of the fixed bed.

These local temperature changes reflect a non-homogeneity of the temperature profile in a plane orthogonal to the direction of the fluid flow. This lack of homogeneity induces a drop in the performance of the storage system and the return of heat. The present invention makes it possible to limit or even to avoid these local changes in temperatures in the fixed bed.

The present invention also relates to a system for storage and energy recovery by compressed gas comprising:

at least one gas compression means;

at least one means for storing compressed gas;

at least one expansion means for the compressed gas;

at least one means for storing and recovering heat, according to at least one variant described above. The means of storing and restoring the heat is positioned between the compression or expansion means and the compressed gas storage means.

By using the means for storing and recovering the heat according to the invention, the thermal performance of the storage and energy recovery system by compressed gas is optimized and consequently, the overall efficiency of the storage and recovery system. Compressed gas energy is increased.

Preferably, several compression and expansion stages can be implemented in order to optimize the overall performance of the system. In this case, at least one means for storing and restoring the heat can be placed between two compression or expansion stages. The number of stages and the ratio of each stage can be chosen depending in particular on the gas and the various constraints of the system to improve the cost / quality ratio.

The gas used may in particular be air, for example air taken from the ambient environment.

Also preferably, a plurality of compressed gas storage tanks can be used. These tanks may have different characteristics from each other, for example, different volumes and / or pressures.

Preferably, a plurality of storage and heat recovery means may also be implemented, each of which may have different characteristics, in order to optimize the overall operation of the system.

The compression means may in particular be a compressor; the detent means may in particular be a turbine.

FIG. 7 illustrates, schematically and in a nonlimiting manner, an exemplary embodiment of an AACAES system according to the invention. In this figure, the arrows in continuous line illustrate the flow of gas during the compression steps (energy storage), and the dashed arrows illustrate the flow of gas during the relaxation steps (energy restitution). This figure illustrates an AACAES system comprising a single compression stage 40, a single expansion stage 50 and a heat storage system 10. The system comprises a storage tank 30 of the compressed gas. The heat storage system 10 is interposed between the compression / expansion stage 40 or 50 and the storage tank 30 of the compressed gas. The heat storage system is realized according to at least one embodiment variant described above. Conventionally, in the energy storage phase (compression), the air is first compressed in the compressor 40, then cooled in the heat storage system 10. The compressed and cooled gas is stored in the tank 30. The heat storage particles of the heat storage system 10 are hot following cooling of the compressed gas in the compression phase. When recovering the energy (expansion), the stored compressed gas is heated in the heat storage system 10. Then, in a conventional manner, the gas passes through one or more expansion stages 50 (a floor according to the example illustrated in Figure 7).

The present invention also relates to a method for storing and recovering heat in which the following steps are carried out:

a) The heat is stored in a fixed bed of storage and heat transfer particles, by circulating a fluid in the fixed bed; and

b) Restores the heat recovered by the fixed bed, by circulating a fluid in the fixed bed

and wherein, for storing and returning heat, the fluid is subjected to at least one obstacle positioned in the fixed bed, perpendicularly or substantially perpendicular to the fluid flow, the obstacle being positioned at the periphery of the fixed bed of storage particles, the obstacle being distributed around the perimeter of the fixed bed of storage particles, continuously or discontinuously. The presence of the obstacle thus positioned in the means for storing and recovering heat makes it possible to locally move the fluid flow from the periphery of the fixed bed. This generates a local modification of the velocity field and therefore the temperature which makes it possible to homogenize the temperature in the bed of particles. In this way, the thermal performance of the process is improved.

The fluid used for the return of heat may be the same or different from the fluid used for the storage of heat.

According to an alternative embodiment of the method according to the invention, the fluid can pass through a stepped arrangement formed by a plurality of fixed beds contained in the means for storing and recovering heat. The system can thus be optimized vis-à-vis various criteria, such as for example and without limitation, to improve the efficiency or minimize the manufacturing cost.

According to one embodiment of the method according to the invention, the fluid can circulate through a cylindrical heat storage or restitution means or substantially cylindrical. This particular geometric shape has the advantage of being simple to manufacture and makes it possible to easily direct the flow of fluid circulation homogeneously through the means of storage and heat recovery.

According to an alternative embodiment of the method according to the invention, the fluid can pass through the fixed bed of the means for storing and restoring the heat radially, that is to say in a direction perpendicular to the axis of the means. storage and return of heat, cylindrical or substantially cylindrical. The specificity of the radial flow makes it possible to better homogenize the temperatures inside the storage enclosure with respect to an axial flow and consequently to improve the thermal performance of the storage and heat recovery means.

Alternatively, the fluid can pass axially through the fixed bed of the heat storage and return means, ie the direction of the flow flow of the fluid is collinear with the axis of the storage medium and heat return. By using an axial flux heat storage and return method, the method is simpler to implement and the overall cost of the process can be minimized.

In addition, the present invention also relates to a method for storage and energy recovery by compressed gas, in which the following steps are carried out:

a) compressing a gas;

b) cooling said compressed gas by heat exchange with a fixed bed of storage particles;

c) the cooled gas is stored;

d) the cooled compressed gas is heated by restoring the heat of the fixed bed of storage particles; and

e) the heated compressed gas is expanded to generate energy.

for which the storage (cooling of the compressed gas) and the restitution (heating of the compressed gas) of the heat are carried out according to the method of storing and restoring the heat as described above. The use of the method for storing and recovering heat, according to at least one of the variants described below, in the method of storing and recovering energy, makes it possible to improve the performance of storage and of heat recovery. By improving these performances, the overall performance of storage and energy recovery by compressed gas is improved.

The gas used may in particular be air, for example air taken from the ambient environment. Steps b) and d) can preferably be implemented by the storage system and heat recovery according to at least one variant described above.

The compression and / or expansion steps can be decomposed into several substeps of compression and / or expansion. This can improve overall system performance and / or optimize cost / quality performance, depending on system and gas constraints. It is also possible to use standard compression and / or expansion means, which makes it possible to limit the costs of designing and manufacturing specific compression and / or expansion elements if necessary.

The compression and expansion steps may in particular be carried out respectively by a compressor and a turbine. During relaxation, the turbine can generate electrical energy. If the gas is air, the expanded air can be vented to the environment.

Step c) can be carried out in a compressed gas storage means, which can be a natural reservoir or not (for example an underground cavity). The compressed gas storage means may be at the surface or in the subsoil. In addition, it may be formed of a single volume or a plurality of volumes connected to each other or not. During storage, the means for storing the compressed gas are closed.

The method and system according to the invention can be used for storage of intermittent energy, such as wind or solar energy, in order to use this energy at the desired time.

FIG. 6 represents a comparative example of implementation of the invention. FIG. 6 illustrates the evolution of the temperature at two diametrically opposite points A and B, positioned at mid-height of the heat storage chamber, for two axial flow cylindrical heat storage and return means. different. The first heat storage and return system corresponds to a system according to the prior art (without obstacle); the second system corresponds to an embodiment according to the invention (according to the configuration of Figure 1). Curves A1 and B1 give the changes in temperature over time on points A and B for the storage and heat recovery system according to the prior art; the curves A2 and B2 give the evolutions of temperatures over time on the points A and B for a system for storing and recovering heat according to one embodiment of the invention. On these curves, there are three zones identified by the letters E, S and R corresponding to times during which the system stores heat (zone E), stores the heat thus stored (Zone S) and then restores the stored heat (Zone R). The two storage and heat recovery systems, apart from the addition of the obstacle for that carried out according to one embodiment of the invention, are identical. It can be observed in FIG. 6 that the temperature peaks observed on the curves A1 and B1 are considerably reduced on the curves A2 and B2. Moreover, the average temperature over the duration of storage is higher, which shows better performance of the system according to the invention, compared to the system according to the prior art.

Claims

claims

1) storage and heat recovery system (10,20) comprising at least one storage chamber (1), at least one fixed bed (2) of storage and heat transfer particles being placed in said enclosure storage (1), and at least one fluid that can flow through said fixed bed (2) in said storage chamber (1), said storage chamber (1) comprising at least one inlet (8) of said fluid in said chamber storage (1) and at least one outlet (9) of said fluid of said storage enclosure (1), characterized in that at least one obstacle (4) is positioned in said fixed bed (2), substantially perpendicular to the flow circulation (3) of said fluid, said obstacle (4) being positioned at the periphery of said fixed bed (2) of said particles for storing and recovering heat, said obstacle (4) being distributed around the perimeter of said bed fixed (2) of said storage particles.

2) System according to claim 1, wherein said system (10,20) comprises at least two obstacles (4) regularly spaced along said flow stream (3) of said fluid.

3) System according to claim 2, wherein the spacing (E) between two of said obstacles (4) successive following said flow stream (3) of said fluid is at least twice the size of said obstacle (4), perpendicular to said flow of circulation (3) of said fluid.

4) System according to one of the preceding claims wherein the storage chamber (1) comprises at least one distributor (5) for dispensing said fluid into said fixed bed (2), and preferably at least two distributors (5). ).

5) System according to claim 4, wherein said obstacle (4) is positioned at said distributor (5).

6) System according to one of the preceding claims for which said obstacle (4) consists of a plate.

7) System according to one of the preceding claims wherein the dimension (L) of said obstacle, perpendicular to said flow of circulation (3) of said fluid, is between 1 and 10 times the Sauter equivalent diameter of said storage particles and restitution heat of said fixed bed (2), preferably between 3 and 5 times the Sauter equivalent diameter of said storage particles and heat recovery of said fixed bed (2).

8) System according to one of the preceding claims for which said storage chamber (1) is cylindrical or substantially cylindrical.

9) System according to claim 8 wherein said flow of circulation (3) of said fluid inside said storage chamber (1) is along the axis of said storage chamber (1). 10) System according to claim 9 wherein said obstacle (4) consists of an annular plate, disposed on the inner face of the cylindrical wall of said storage chamber (1).

1 1) System according to claim 8 for which said circulation flow (3) of said fluid inside said storage chamber (1) is along an axis perpendicular to the axis of said storage enclosure (1), at least two support trays (6) of said fixed bed (2) being positioned inside said storage enclosure (1), said support trays (6) being perpendicular to the axis of said storage enclosure (1) ).

12) System according to claim 1 1 for which said obstacle (4) is positioned on said support plates (6), the obstacle (4) then forming a piece of cylinder on each of the two support plates (6) of said bed fixed (2) of said particles for storing and recovering heat.

13) System according to one of the preceding claims wherein said obstacle (4) is distributed continuously over the periphery of the periphery of said fixed bed (2).

14) System according to one of the preceding claims wherein said obstacle (4) is distributed discontinuously around the periphery of said fixed bed (2).

15) compressed gas energy storage and recovery system comprising at least one gas compression means (40), at least one compressed gas storage means (30), at least one expansion means of said compressed gas ( 50) for generating energy, and at least one heat storage means (10, 20) according to one of the preceding claims.

16) Process for storing and recovering heat, in which the following steps are carried out:

a) The heat is stored in a fixed bed (2) of storage and heat recovery particles, by circulating (3) a fluid in said fixed bed (2); and

b) recovering the heat recovered by said fixed bed (2), by circulating (3) a fluid in said fixed bed,

characterized in that for storing and returning heat, said fluid is subjected to at least one obstacle (4) positioned in the fixed bed (2), perpendicularly or substantially perpendicularly, to the flow (3) of said fluid, said obstacle (4) being positioned at the periphery of said fixed bed (2) of said storage and heat recovery particles, said obstacle (4) being distributed around the perimeter of said fixed bed (2) of said storage and heat recovery particles,

17) The method of claim 16, wherein said fluid passes through a stepped arrangement formed by a plurality of said fixed beds (2) contained in said heat storage and retrieval means (10, 20). 18) Method according to one of claims 16 and 17, wherein said means for storing and restoring the heat (10, 20) is of substantially cylindrical shape

19) The method of claim 18, wherein said fluid flows radially through said fixed bed (2) of said means for storing and returning heat (10, 20).

20) Method according to claim 18, wherein said fluid passes axially through said fixed bed

(2) said means for storing and returning heat (10, 20).

21) Process for storage and energy recovery by compressed gas, in which the following steps are carried out:

a) compressing a gas;

c) storing said cooled gas;

e) said heated compressed gas is expanded to generate energy.

for which the storage and the return of the heat are carried out according to the method of storing and restoring the heat according to one of claims 16 to 20.