Improved recovery unit, sterilisation device and associated method

Abstract

The invention relates to a recovery unit (10) comprising: a heat exchanger (102), a storage module (100) comprising two tanks (110, 120) comprising a first system (108) for injecting and withdrawing a storage fluid in the lower part (110b) of the tank (110, 120), a storage circuit (101) connecting the storage module (100) and the heat exchanger (102), the tanks (110, 120) having a storage fluid fill level (50), and the tanks (110, 120) each comprising a second injection and withdrawal system (111) comprising: a body (1110) movable in a vertical direction (z) in the tank (110, 120), and a module (1111) for injecting and withdrawing the storage fluid (5) so as to draw off and inject the fluid (5) at a variable height depending on the fill level.

Description

[0001] "Improved recovery unit, sterilization device and associated process"

[0002] TECHNICAL FIELD OF THE INVENTION

[0003] The present invention relates to the field of energy recovery and optimization of thermal energy use. Its application is particularly advantageous in the field of sterilizers that use heat intermittently to carry out a sterilization cycle.

[0004] STATE OF THE ART

[0005] The ecological optimization of industrial equipment and processes is an approach that manufacturers are increasingly adopting. In addition to its positive impact on the environment, ecological optimization contributes to a company's image. Ecological optimization commonly involves energy optimization, leading to cost reductions.

[0006] Among the industrial processes that can be optimized, sterilization devices and processes are major consumers of energy and water, a significant portion of which is not recycled. One area of ​​research focuses on storing the waste heat generated by these sterilization processes.

[0007] A seemingly obvious and simple thermal storage solution would involve filling a tank with hot water recovered during the sterilizer's cooling phase, and then releasing the heat from this stored hot water during the heating phase of the following cycle. In this configuration, the collected hot water is mixed with the existing water in the storage tank, leading to a gradual homogenization of its temperature. Despite its simplicity, this system has a significant operational limitation: during the subsequent heating phase of the sterilizer, the heat storage solution can only be used as long as the water temperature at its outlet is sufficient to maintain the temperature of the process water supplying the sterilizer.However, the homogenization of the water temperature during its recovery and storage greatly limits the possibilities of exploiting this recovered heat and leads to considering large storage volumes in order to ultimately utilize only a small amount of thermal energy.

[0008] Document EP3882555 A1 describes a recovery unit comprising a thermal energy storage module receiving a storage fluid, a heat exchanger, and a thermal storage circuit fluidly connecting the storage module and the heat exchanger and ensuring the circulation of the storage fluid. The heat exchanger is intended to be used in conjunction with a sterilizer to exchange thermal energy between the sterilizing fluid circulating in the sterilizer and the storage fluid.

[0009] This energy recovery unit utilizes the physical effect known as the "thermocline," and therefore the natural temperature stratification of the storage fluid within the tank. The storage fluid intended for the storage module has a volume smaller than the module's volume, thus maintaining a buffer volume. The energy storage module also includes at least two sensible heat storage tanks. Each tank is equipped with a storage fluid injection and withdrawal system located at its base, for drawing in or injecting the storage fluid.

[0010] This type of storage, however, is not optimal for recovering and reusing waste heat. Specifically, the storage fluid is not stored optimally during heat release phases. Furthermore, in this system, the extraction of the storage fluid may not perfectly follow the temperature setpoint during a sterilization cycle.

[0011] One object of the present invention is therefore to provide a solution that improves the recovery and utilization of recovered thermal energy. More specifically, one object of the present invention is to provide a solution that improves the recovery of thermal energy from systems involving a process with an initial temperature rise phase (heating) and / or a temperature fall phase (cooling), such as sterilizers.

[0012] The other objects, features, and advantages of the present invention will become apparent from an examination of the following description and accompanying drawings. It is understood that other advantages may be incorporated.

[0013] SUMMARY OF THE INVENTION

[0014] To achieve this objective, the first aspect involves a valuation unit comprising:

[0015] - a heat exchanger,

[0016] - a thermal energy storage module configured to receive a storage fluid, the storage module comprising at least two tanks, each intended to receive the storage fluid and each comprising a first injection and withdrawal system for the storage fluid arranged in the lower part of said tank, the first injection and withdrawal system being configured to draw and inject the storage fluid into the lower part of said tank, the storage module further comprising an empty volume called a buffer volume, the storage fluid intended to be stored in the storage module representing a volume less than the volume of the storage module so as to maintain the buffer volume,

[0017] - a thermal storage circuit configured to fluidly connect the storage module and the heat exchanger to ensure the circulation of the storage fluid.

[0018] Advantageously, the at least two tanks are designed to have a fill level of storage fluid, separating a filled sub-volume and an empty sub-volume, and in that the at least two tanks each include a second system for injecting and withdrawing the storage fluid, each second injection and withdrawal system comprising:

[0019] - a body configured so as to be at least partially mobile along a vertical direction within said reservoir, and

[0020] - a storage fluid injection and withdrawal module fluidically connected to the body, so as to draw and inject the storage fluid at a variable height, said height being a function of the storage fluid filling level of said tank.

[0021] Thus, the recovery unit allows for the injection and withdrawal of the storage fluid at the storage fluid filling level in the tank in question. For example, during the discharge of the thermal storage system, i.e., the heating of the process by releasing the stored heat, the invention allows the flow rate of the storage fluid at the storage fluid filling level (i.e., from bottom to top) to be injected into the tank selected for filling, so as to store the storage fluid in the direction of temperature stratification.

[0022] During the charging of the thermal storage means, i.e. the cooling of the process by recovering its heat, the invention makes it possible to take the flow of the storage fluid from top to bottom (at the level of the free surface), i.e. in the direction of the temperature stratification, in the tank selected to be emptied.

[0023] In existing solutions that only involve injection and withdrawal from the bottom of the tanks, during the discharge of the thermal storage system—that is, when the stored heat is to be released, particularly during the heating phase of a sterilizer—the fluid is withdrawn from a first tank, circulates through the storage circuit to the heat exchanger, and is then reinjected into a second tank as cooled storage fluid. The cooled storage fluid is injected into this second tank from its bottom. However, the temperature of the cooled storage fluid returning to this second tank typically increases during the heating phase of a sterilizer.Injecting an increasingly hot storage fluid from below is energetically unfavorable because it leads to the degradation of the quality of the stored energy (exergy), due to the convection movements initiated which promote the mixing and homogenization in temperature of the storage fluid in the tank concerned.

[0024] In these existing solutions, during the charging of the thermal storage system—that is, the cooling of the process by recovering its (waste) heat—the flow of storage fluid drawn from the selected tank to be emptied is taken from its bottom. If temperature stratification of the storage fluid has nevertheless developed (despite the previous consideration during the preceding discharge) in the emptied tank, the extracted flow will be increasingly warm, while the cooling requires an increasingly colder heat source. Depending on the heat exchange conditions, this operation can constrain and limit the operation of the energy recovery system (for example, by requiring the tank being emptied to be changed to a colder one even though the tank being emptied is not yet empty).

[0025] It is therefore understood that the recovery and use of thermal energy is improved, particularly for a system involving a schedule with an initial temperature rise phase (heating), and / or a temperature fall phase (cooling), such as a sterilizer.

[0026] A second aspect concerns a sterilization device comprising a sterilizer and a recovery unit according to the first aspect.

[0027] According to one example, the sterilization device includes a cold source inlet different from the storage fluid and a hot source inlet different from the storage fluid.

[0028] A third aspect concerns a process for recovering thermal energy using a recovery unit, as described in the first aspect, where the recovery unit receives a storage fluid, and the process includes a step of charging the storage module comprising:

[0029] - the withdrawal of the storage fluid by the second injection and withdrawal system from one of the at least two storage tanks, to a height in said tank depending on the filling level of storage fluid, for the circulation of the storage fluid in the storage circuit in order to exchange thermal energy in the heat exchanger,

[0030] - the injection of the storage fluid into the buffer volume.

[0031] A fourth aspect, possibly combinable with the process according to the third aspect, concerns a process for recovering thermal energy by a recovery unit according to the first aspect, the recovery unit receiving a storage fluid, the process including a step of discharging the storage fluid comprising:

[0032] - the withdrawal, by the first injection and withdrawal system, of the storage fluid from the lower part of a storage tank, from among at least two storage tanks for the circulation of the storage fluid in the storage circuit in order to exchange thermal energy in the heat exchanger,

[0033] - the injection of the storage fluid into the buffer volume.

[0034] BRIEF DESCRIPTION OF THE FIGURES

[0035] The aims, objects, features and advantages of the invention will become clearer from the detailed description of an embodiment thereof, which is illustrated by the following accompanying drawings in which:

[0036] Figure 1 is a graph of the setpoint temperature of the sterilizing fluid according to the phase of the cycle, also called the schedule, as a function of time in a sterilizer during a sterilization cycle, according to an example.

[0037] Figure 2 represents a simplified piping and instrumentation diagram (or Process and instrumentation diagram, abbreviated P&ID) of a superheated pressurized storage fluid sterilization device, incorporating the recovery unit according to an example in which the recovery unit comprises two tanks.

[0038] Figure 3 shows a piping and instrumentation diagram (P&ID), based on an example in which the storage module 100 of the recovery unit comprises four tanks, during a charging phase. The second injection and withdrawal systems are mounted on the upper part of the tank in this example.

[0039] Figure 4 represents a piping and instrumentation diagram (P&ID) based on the example shown in Figure 3, during a discharge phase.

[0040] Figures 5 and 6 represent a diagram of a tank including a second injection and withdrawal system mounted at the top of the tank, as an example, respectively during and at the end of injection when the tank is filled.

[0041] Figures 7 and 8 represent a diagram of a tank including a second injection and withdrawal system mounted in the lower part of the tank, as an example, respectively at the beginning and during injection.

[0042] Figure 9 shows a piping and instrumentation diagram (P&ID), based on an example in which the storage module 100 of the recovery unit comprises four tanks during a charging phase. The second injection and withdrawal systems are mounted at the bottom of the tank in this example.

[0043] Figure 10 represents a piping and instrumentation diagram (P&ID) according to the example illustrated in Figure 9, during a discharge phase.

[0044] Figure 11 shows a cross-sectional view of the body of an injection and withdrawal system, as an example.

[0045] The drawings are given as examples and are not limiting to the invention. They constitute schematic representations of principle intended to facilitate understanding of the invention and are not necessarily to scale with practical applications.

[0046] DETAILED DESCRIPTION OF THE INVENTION

[0047] Before beginning a detailed review of embodiments of the invention, optional features that may be used in combination or alternatively are stated below.

[0048] According to one example, the energy storage module and the first and second and the storage fluid injection and withdrawal system are configured to promote the formation and maintenance of temperature stratification.

[0049] As an example, the body of at least one, and preferably each, second injection and withdrawal system has a deployed configuration and a plurality of retracted configurations, so as to modify the body's length along the vertical z-direction as a function of the storage fluid fill level. The second injection and withdrawal system thus adapts flexibly to the fill level by contracting or deploying along the vertical z-direction. This limits the disturbance of stratification in the retracted configurations compared to a fixed-length device that would be more or less twisted depending on the storage fluid fill level. Thermal mixing of the storage fluid in the tanks can therefore be limited during injection and withdrawal.

[0050] According to one example, the body of at least one, and preferably each, second injection and withdrawal system is telescopic and slides along a main body deployment direction.

[0051] As an example, the tank body has an internal hydraulic cross-section, measured substantially perpendicular to the main direction of deployment, increasing along this direction towards the injection and withdrawal module. The second injection and withdrawal system thus progressively reduces the flow velocity of the storage fluid up to the hydraulic injection or withdrawal point, which is more favorable for controlling thermal stratification within the tank.

[0052] According to one example, the body of said second injection and withdrawal system comprises:

[0053] - a set of coaxial telescopic tubes configured together to slide along the main direction of deployment of the body, and

[0054] - a rotational locking device, around the main direction of deployment of the body, of the telescopic tubes relative to each other.

[0055] The locking device ensures the centering of the coaxial telescopic tubes and prevents their rotation, so that the body of the second injection and withdrawal system moves only in a linear fashion. Thermal mixing of the storage fluid in the tanks can therefore be further limited during the contraction and extension of the body, and thus during the injection and withdrawal of the storage fluid.

[0056] In one example, the at least two tanks have an upper section in which the body of at least one, and preferably each, second injection and withdrawal system extends from the upper section of said tank so as to extend primarily within the empty sub-volume. The moving body of the second injection and withdrawal system is therefore primarily mobile within the empty sub-volume. This minimizes the disturbance of the storage fluid when the second injection and withdrawal system adapts to the fill level. The thermal stratification within the tank is thus better preserved.

[0057] As an example, at least one, and preferably every second, injection and withdrawal system is configured to draw and inject the storage fluid, via the injection and withdrawal module, at a distance extending into the filled sub-volume from the fill level, the distance being, for example, between 0 cm and 20 cm. The closer the injection is to the free surface, the more optimized the thermal stratification.

[0058] As an example, the injection and withdrawal module of at least one, and preferably each, second injection and withdrawal system includes a flotation device. This allows the injection and withdrawal system to passively follow changes in the storage fluid level in the tank. Specifically, the flotation device ensures that the injection or withdrawal of the storage fluid occurs just below or at the level of the liquid free surface of the storage fluid contained in the tank.

[0059] As an example, the injection and withdrawal module of at least one, and preferably each, second injection and withdrawal system is configured to inject or withdraw the storage fluid radially. This makes the velocity profile of the injected or withdrawn storage fluid flow rate more homogeneous. This limits the temperature mixing phenomenon between the volume of storage fluid contained in the tank at the injection or withdrawal point and the injected or withdrawn storage fluid flow rate.

[0060] According to one example, said injection and withdrawal module comprises at least two plates at least partially superimposed along the vertical direction z, the at least two plates delimiting a spacing having a rotational symmetry around the vertical direction z and permitting the injection and withdrawal of the storage fluid.

[0061] In one example, the recovery unit further comprises, for each of the at least two tanks, a first fluid-selective valve connected to the first injection and withdrawal system, and a second fluid-selective valve connected to the second injection and withdrawal system. The first and second valves are configured to select one of the first and second injection systems to inject or withdraw the storage fluid. Thus, the unit allows the selection of either injection or withdrawal system depending on the stage of the cycle, in order to optimize temperature stratification.According to one example, the thermal storage circuit includes, for each of the at least two tanks, a first pipe intended to convey the storage fluid to the inlet of said tank and a second pipe intended to convey the storage fluid (5) to the outlet of said tank, and a third pipe forming a common sub-branch of the first and second pipes, and positioned downstream of the first pipe and upstream of the second pipe in the direction of flow of the storage fluid, the first and second selection valves being fluidly connected to the third pipe.

[0062] According to one example, the recovery unit includes a storage module management module configured to control the injection and withdrawal system of the storage fluid according to a temperature setpoint in the heat exchanger.

[0063] According to one example, the buffer volume corresponds to the volume of at least one reservoir.

[0064] As an example, the thermal storage circuit is configured to operate in a closed loop.

[0065] According to one example, the storage module includes a system for homogenizing and distributing the flow of the storage fluid injected throughout the hydraulic section of at least two tanks.

[0066] According to one example, the recovery unit includes a pressurization module for at least two storage tanks configured to maintain sufficient pressure to keep the storage fluid in a liquid state.

[0067] In one example, the storage module includes four tanks.

[0068] In one example, the recovery unit includes the storage fluid.

[0069] In one example, the storage fluid is water.

[0070] According to an example, during the withdrawal, the tank from which the storage fluid is withdrawn includes the storage fluid exhibiting temperature stratification.

[0071] According to an example, during the injection stage, the buffer volume is a different tank from the storage tank from which the storage fluid is drawn, the storage fluid is injected into the lower part of the tank by the first injection and withdrawal system and arrives increasingly cold, ensuring thermal stratification of the storage fluid in the buffer volume.

[0072] According to one example, the control of the injection and withdrawal system of the storage fluid is based on a temperature setpoint in the heat exchanger, and is carried out by the management module of the storage module.

[0073] According to an example, during the withdrawal stage, the storage fluid is drawn from the tank, comprising the temperature-stratified storage fluid. With withdrawal carried out from the lower part, the extraction begins with the coldest storage fluid and progresses to the warmest.

[0074] According to an example, during the injection stage, the buffer volume is a different tank from the storage tank from which the storage fluid is drawn, the storage fluid is injected by the second injection and withdrawal system from said storage tank, to a height in said tank depending on the level of filling in storage fluid, and arrives increasingly hot and is thermally stratified as the storage fluid is injected into said tank.

[0075] According to one example, the valorization unit further comprising, for each of the at least two tanks, a first fluidly connected selection valve to the first injection and withdrawal system, and a second fluidly connected selection valve to the second injection and withdrawal system, the process further comprises a selection of the injection and withdrawal system to be used, from among the first and second injection and withdrawal systems.

[0076] According to one example, the body of at least one, and preferably of each, second injection and withdrawal system is deployable or retractable over at least 10%, preferably at least 20%, preferably at least 30%, preferably at least 50%, and preferably at least 80%, of the height of the tank.

[0077] In the following description, the term "on" does not necessarily mean "directly on." Thus, when it is stated that a part or component A rests "on" a part or component B, this does not mean that parts or components A and B are necessarily in direct contact with each other. These parts or components A and B may be either in direct contact or supported by one or more other parts. The same applies to other expressions such as, for example, "A acts on B," which can mean "A acts directly on B" or "A acts on B through one or more other parts."

[0078] In this patent application, the term mobile corresponds to a rotational movement or a translational movement or a combination of movements, for example the combination of a rotation and a translation.

[0079] In this patent application, when two parts are described as distinct, it means that these parts are separate. They may be:

[0080] - positioned at a distance from each other, and / or

[0081] - mobile relative to each other and / or

[0082] - joined together by being fixed by added elements, this fixing being removable or not. A single, monobloc part therefore cannot be made up of two separate parts.

[0083] In this patent application, the term "fixed" used to describe the connection between two parts means that the two parts are linked / fixed to each other with respect to all degrees of freedom, unless explicitly stated otherwise. For example, if it is stated that two parts are fixed in translation along a direction X, this means that the parts can move relative to each other, possibly with several degrees of freedom, excluding freedom in translation along the X direction. In other words, if one part is moved along the X direction, the other part moves in the same direction.

[0084] In the detailed description that follows, terms such as "horizontal," "vertical," "longitudinal," "transverse," "upper," "lower," "top," "bottom," "front," "back," "inside," and "outside" may be used. These terms should be interpreted relatively in relation to the normal position of the recovery unit. For example, the term "vertical" refers to the normal to the free surface of a fluid in a tank.

[0085] We will also use a reference frame whose longitudinal or back / front direction corresponds to the X axis, the transverse or right / left direction corresponds to the Y axis and the vertical or bottom / up direction corresponds to the Z axis.

[0086] For the purposes of this disclosure, "A and / or B" means (A), (B), or (A and B). For the purposes of this disclosure, "A, B and / or C" means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).

[0087] A parameter that is "approximately equal to / greater than / less than" a given value means that the parameter is equal to / greater than / less than the given value, within ±10% of that value. A parameter that is "approximately between" two given values ​​means that the parameter is at least equal to the smaller of the two given values, within ±10% of that value, and at most equal to the larger of the two given values, within ±10% of that value.

[0088] The invention is now described with reference to several specific embodiments, as shown in the figures. For the purposes of this description, the recovery unit 10 is intended to recover and utilize thermal energy with a sterilizer 200, which may also be called an autoclave. Other applications are possible, however, as the invention is particularly advantageous for systems involving a process with an initial heating phase and / or a cooling phase. Typically, and as illustrated in Figure 1, during a sterilization process, the load inside the sterilizer 200 undergoes a thermal cycle consisting of heating (1), temperature maintenance (2) by a hot source such as a boiler generating steam (F4), and cooling (3) by a cold source (F5) such as mains water.The heat released into the municipal water supply during sterilization cycles represents a significant energy resource, typically amounting to approximately 300 kWh to 400 kWh per cycle. Given that some industrial sites operate sterilizers up to 20 cycles per day, these discharges exceed 2 GWh and 50,000 m³. 3 of water per year per sterilizer, if cooling is provided by an open-loop water system (i.e., a one-way waste). Most of the time, the cooling water is in a closed loop and is cooled by a cooling tower. The equivalent annual gas consumption is estimated at between 93,000 Nm³ 3 and 124,000 Nm 3(in normal cubic meters, a unit of measurement for the quantity of gas corresponding to the contents of a volume of one cubic meter, for a gas under normal temperature and pressure conditions). The equivalent amount of CO2 released (assuming 227 gCO2 / kWh) is estimated to be between 204 and 272 tonnes of CO2 / year.

[0089] The sterilization process is batch-controlled, which precludes the use of a simple heat exchanger 102 to preheat the water entering the boiler. Using a storage system to recover and store waste heat for reuse in a subsequent cycle eliminates the problem that the heating (1), temperature maintenance (2), and cooling (3) phases are out of phase and occur at different times.

[0090] The recovery unit 10 at least partially replaces the supply of steam F4 or cold F5 for part of the cycle. As illustrated in Figure 1, one objective of the invention is to recover F2 and store some of the heat extracted during the cooling 3 of the sterilizer 200 in order to release it F1 to provide part of the heating phase of a subsequent cycle, for example, the one immediately following it. We can therefore distinguish:

[0091] - a phase 3 of heat recovery or equivalently of charging the storage module 100 (cooling of the sterilizer 200) during which the hot source decreases in temperature,

[0092] - a phase 1 of heat restitution or equivalently of discharge of the storage module 100 (heating of the sterilizer 200) during which the cold source increases in temperature.

[0093] Because of these temperature scales, the sensible heat storage module 100 is more likely to exhibit a temperature gradient established along its height, rather than a hot (quasi-isothermal) volume separated from a cold (quasi-isothermal) volume by a thermocline thickness, which is the case most commonly encountered when the source temperatures are constant.

[0094] This solution thus saves some of the thermal energy needed to heat (steam) and cool (cooling water) sterilizer 200, by utilizing what is currently a waste heat source. Therefore, when the heat transfer fluid 5, also called the storage fluid, from storage module 100, is able to heat or cool sterilizer 200 according to the schedule, the recovery unit 10 can be used to supplement or replace the usual steam or cooling supply methods (also called utilities).As explained later, the recovery unit 10 initially maintains the temperature levels of the recovered waste heat, for example, during cooling, and then subsequently releases it in the opposite direction, in a gradually increasing temperature ramp, without altering it, which would reduce its energy recovery. The water from the storage module 100 returns to the storage module 100 after passing through the heat exchanger 102, thus forming the thermal storage circuit 101, which is preferably closed. When the storage module 100 is no longer able to heat or cool the sterilizer 200, the usual means can take over directly.

[0095] Conventional steam or cold supply methods can operate in a clean circuit, independently of the recovery unit 10. The recovery unit 10 minimizes their use and therefore the consumption of primary energy, typically gas.

[0096] As illustrated in Figure 2, the recovery unit 10 comprises a thermal storage module 100. The thermal storage module 100 of the recovery unit 10 advantageously provides sensible heat storage. The recovery unit 10 according to the invention can be installed on existing or new sterilization plants.

[0097] The thermal storage module 100 is suitable for receiving a storage fluid 5. According to an example, the thermal storage module 100 includes the storage fluid 5.

[0098] The storage fluid 5 is advantageously a heat transfer fluid chosen to operate at the application temperature, in this case for a sterilizer 200. For example, the storage fluid 5 is water. This choice facilitates the successive circulation of the storage fluid 5, a hot source, and a cold source in the heat exchanger 102, and in particular in a first fluid circuit and a second fluid circuit of the heat exchanger 102. The water is preferably pressurized and potentially superheated. Other fluids can be considered, such as thermal oil.

[0099] The recovery unit 10 according to the invention comprises a thermal storage circuit 101. The thermal storage circuit 101 is a hydraulic circuit, advantageously a circuit capable of operating in a closed loop. The storage circuit 101 is connected to the storage module 100 so as to store and release the storage fluid 5. The storage circuit 101 is capable of receiving the storage fluid 5 and advantageously of ensuring its circulation.

[0100] The recovery unit 10 advantageously includes a heat exchanger 102. Preferably, the recovery unit includes a heat exchanger 102 intended to be associated with a sterilizer 200. The association is between a heat exchanger 102 and a sterilizer 200. The heat exchanger 102 is arranged on the thermal storage circuit 101. The storage fluid 5 circulating in the storage circuit 101 exchanges thermal energy in the heat exchanger 102 advantageously with a sterilization fluid intended to circulate in the sterilizer 200 and ensure sterilization. The exchanger 102 can be, for example, a shell-and-tube or plate heat exchanger.

[0101] The recovery unit 10 can possibly include several sterilizers 200. In this way, the recovery unit 10 is shared for several heat exchangers 200.

[0102] The thermal storage module 100 preferably comprises at least two tanks 110, 120, 130, 140. In the following description, the use of the term "tanks" in the plural refers to "at least two tanks." Tanks 110, 120, 130, 140 are understood to be distinct volumes from which the injection and withdrawal of storage fluid 5 is independent. The storage module 100 is configured to allow for natural thermal stratification. Advantageously, the tanks 110, 120, 130, 140 extend vertically along the z-direction so as to conform to configurations favorable to the establishment of thermal stratification within their volume.

[0103] Advantageously, according to the invention, the storage fluid 5 intended to be stored in the storage module 100 represents a volume that is less than the volume of the storage module 100 so as to maintain an empty volume in the storage module 100. This buffer volume does not contain any storage fluid 5. This empty volume is a buffer volume. The buffer volume is advantageously present in all stages of use of the recovery unit 10, that is to say, during loading and unloading. The buffer volume is intended to allow the injection of storage fluid 5 into the buffer volume when the storage fluid is withdrawn from a tank 110, 120, 130, or 140, preferably so as not to mix the storage fluid 5 intended to be withdrawn with the injected storage fluid, that is to say, the storage fluid 5 intended for the heat exchanger 102 and the storage fluid returning from the heat exchanger 102.Temporarily, the storage fluid 5 may be drawn off and then injected into the same tank. This situation can occur, for example, when the temperature of the fluid discharged from one of the tanks in the recovery unit is insufficient to meet the setpoint temperature (Tstockfrom limit) required by the schedule. Specifically, this situation arises if, during the storage tank's charging phase (i.e., the sterilizer's cooling), the temperature of the tank being discharged is higher than the setpoint, or if, during the storage tank's discharge phase (i.e., the sterilizer's heating), the temperature of the tank being discharged is lower than the setpoint. This leads to a change in the tank being discharged or to the shutdown of the storage system, leaving one tank partially emptied and another partially filled.

[0104] The presence of a buffer volume helps ensure thermal stratification for eventual use. The buffer volume increases the thermal energy that can be stored in the storage module 100 and facilitates the storage and release of the storage fluid 5.

[0105] Preferably, the buffer volume corresponds to the volume of at least one reservoir 110, 120, 130, 140. In one embodiment, the reservoir 110, 120, 130, 140 forming the buffer volume changes depending on the storage and release phases of the storage fluid 5; different reservoirs 110, 120, 130, 140 are used alternately as a buffer volume. In another possibility, each reservoir 110, 120, 130, 140 is used alternately as a buffer volume.

[0106] According to one embodiment, reservoirs 110, 120, 130, 140 are used in communicating vessels.

[0107] In a more advantageous configuration in terms of energy storage density and the quality of the stored thermal energy, the storage module 100 is advantageously composed of more than two tanks 110, 120, 130, 140. Indeed, according to the present invention, the greater the number of tanks 110, 120, 130, 140, the smaller the buffer (empty) volume compared to the energy-recovered storage volume. For example, if the storage module 100 comprises two tanks 110, 120, 130, 140, only half of the total storage volume is used, whereas if the storage module 100 has four tanks, three-quarters of the total storage volume is used. The greater the number of tanks, the lower the ratio of empty tanks to the total number of tanks.

[0108] Similarly, the greater the number of tanks 110, 120, 130, and 140, the more thermal stratification can be achieved by discretizing the storage tanks, filled during the discharge phase (i.e., during the heating of sterilizer 200), into different homogeneous temperature levels. During this phase, natural thermal stratification is difficult to control without modifying the design of the storage module. This configuration is therefore particularly energy-efficient since, at the end of the heating phase of sterilizer 200, tanks 110, 120, 130, and 140 are filled with a storage fluid at different (homogeneous) temperature levels.

[0109] The storage module 100 advantageously includes a first injection and withdrawal system for the storage fluid 108 from the tanks 110, 120, 130, 140. Preferably, the first injection and withdrawal system 108 is arranged in the lower part 110b of each of the tanks 110, 120, 130, 140. Preferably, the storage module 100 includes a first injection and withdrawal system 108 per tank.

[0110] This lower section 110b, however, leads existing recovery solutions, which only implement a first injection and withdrawal system 108, to mix the storage fluid injected into at least one of the tanks 110, 120, 130, 140 during a discharge step of the storage module 100. In these solutions, during this discharge step, and therefore during the heating of the sterilizer 200, a flow of storage fluid 5 returning from the heat exchanger 102 is then injected into a tank via the lower section 110b into a volume of storage fluid 5 already present, which is at a lower temperature. This results in mixing that leads to a temporary homogenization of the temperature of the storage fluid 5 within the tank. The temperature stratification is, at the very least, disrupted and often lost, at least temporarily.Temperature homogenization is an inherent consequence of injecting a flow of warmer storage fluid (returning from heat exchanger 102) through the lower part of the tanks into a volume of cooler storage fluid 5 already present in the tank. When storage fluid 5 is drawn from a tank to heat sterilizer 200, the storage fluid is initially temperature stratified (since it was stratified during the previous cooling phase of sterilizer 200).

[0111] Furthermore, during the charging of the thermal storage module 100, i.e., the cooling of the process by recovering waste heat from the sterilizer, the flow of storage fluid 5 drawn from the selected tank to be emptied is drawn from its lower section 110b. If temperature stratification of the storage fluid has nevertheless developed (despite the homogenization considerations seen previously during the preceding discharge) in the emptied tank, the extracted flow will be increasingly warm, while the cooling requires an increasingly cold heat source. Energy recovery is therefore not optimal. Note that for an increasingly cold heat source, the term "cooling source" can be used (to refer to cold as opposed to "calorie" to refer to heat).

[0112] To avoid this, at least two tanks 110, 120, 130, 140, and preferably each tank, include a second injection and withdrawal system 111 for the storage fluid 5. The second injection and withdrawal system 111 is configured to adapt to the fill level 50 of the storage fluid 5 in the corresponding tank. The storage fluid 5 in each tank 110, 120, 130, 140 has a fill level 50, which separates a sub-volume filled with storage fluid 5 from an empty sub-volume. The fill level 50 therefore corresponds to the free surface of the storage fluid 5 in a tank. When the tank is full, the empty sub-volume can be zero. When the tank is empty, the filled sub-volume can be zero.

[0113] The second injection and withdrawal system 111 of the storage fluid 5 is configured to draw and inject the storage fluid at a variable height along the vertical direction z in the tank 110, 120, 130, 140 under consideration. This height is a function of the level of the storage fluid in the tank.

[0114] More specifically, the second injection and withdrawal system 111 is configured to inject or withdraw the storage fluid 5 at the fill level 50 or just below, and for example at a vertical distance D from the free surface, between 0 cm and 20 cm, preferably between 0 cm and 10 cm, and even more preferably between 0 cm and 5 cm. It is therefore understood that this distance D can be zero. As an example, this distance is illustrated in Figures 5 to 8. The distance D can be taken between the free surface 50 of the storage fluid 5 in the tank and the median plane of withdrawal or injection of the storage fluid by the second injection and withdrawal system 111. In the following, it is assumed, for the sake of completeness, that the injection and withdrawal take place at the fill level 50.

[0115] Thus, the second injection and withdrawal system 111 makes it possible to monitor the variable storage fluid level 5 of the tank selected to be emptied or filled, so as to allow:

[0116] - During the charging phase (illustrated for example in Figure 3), a progressively colder flow of storage fluid is drawn off, up to the level of the free surface of the decreasing fluid level in the emptying tank. The temperature schedule is thus followed for the cooling of sterilizer 200.

[0117] - During the discharge phase (illustrated for example in figure 4), an increasingly hot flow of storage fluid 5 is injected, at the level of the increasing free surface of the storage fluid 5 in the filling tank. Thermal stratification is then maintained.

[0118] During the cooling phase of the sterilizer 200, i.e., the charging phase of the storage module 100 as illustrated in Figure 3, the storage fluid 5 returning from the heat exchanger 102 is injected into the storage module 100, controlling thermal stratification. This thermal stratification is made possible by the fact that the storage fluid 5 returning from the heat exchanger 102 during the cooling phase is increasingly cold and is injected through the lower part 110b of the selected reservoir for filling.

[0119] The storage circuit 101 includes a first branch 104 originating from the heat exchanger 102 and supplying the thermal storage module 100 (stock-to). The first branch 104 is fluidly connected to an outlet of the heat exchanger 102 and to an inlet of the storage module 100. The storage circuit 101 includes a second branch 105 originating from the thermal storage module 100 and supplying the heat exchanger 102 (stock-from). The second branch 105 is fluidly connected to an outlet of the storage module 100 and to an inlet of the heat exchanger.

[0120] The storage circuit 101 is preferably configured to operate in a closed loop. Note that it is possible to add storage fluid 5, for example via a top-up valve 103.

[0121] The storage module 100, and in particular the tanks 110, 120, 130, and 140, are preferably connected in parallel to the storage circuit 101. Each tank 110, 120, 130, and 140 can be connected to the first branch 104 and the second branch 105, respectively, by a first line 11 and a second line 12. The first line 11 is fluidly connected to the first branch 104, supplying the tank with storage fluid 5. The second line 12 is fluidly connected to the second branch 105, supplying the storage fluid 5 from the tank.

[0122] Each line 11, 12 advantageously includes a thermally controlled hydraulic isolation valve. The opening or closing of the isolation valve is controlled according to the temperature of the storage fluid, preferably measured at its point of inlet (T stock-n,oou 1, with n the tank number and 0 for a measurement of the storage fluid 5 passing through the first injection and withdrawal system 108 and 1 for a measurement of the storage fluid 5 passing through the second injection and withdrawal system 111), and a predefined temperature setpoint, preferably evaluated based on the temperature to be reached by the sterilization fluid at its outlet from the heat exchanger (Ts-rw,to) when it is heated or cooled respectively by a hot source or by a cold source, which may be the storage fluid 5. The isolation valves are designated Vstockn- from for the control valves of the outlet of the storage fluid from a tank n. They are advantageously arranged on the second lines 12. The isolation valves are designated Vstockn -to for the control valves of the inlet of the storage fluid into a tank n. They are advantageously arranged on the first 11 pipes.These Vstockn-from and / or Vstockn-to isolation valves allow selection of which tank should be emptied and which tank should be filled, based on their states and the phase of the sterilization cycle being performed. Advantageously, these Vstockn-from and / or Vstockn-to isolation valves are on / off valves, meaning they are open / closed.

[0123] Each tank 110, 120, 130, 140 may further include two selector valves controlled by the injection and withdrawal system 108, 111 to be used. These valves are advantageously fluidically connected to, for example positioned on, a third line 13 forming a sub-branch common to the lines 11, 12. Thus, it is possible to select the first 108 or second 111 injection and withdrawal system, for injecting or withdrawing the storage fluid 5 for the circulation of the storage fluid 5 in the corresponding line 11, 12.

[0124] The Vstockn, IF valve of each tank n can be fluidly connected to the first injection and withdrawal system 108 located in the lower part 110b of the tank. The Vstockn, sv valve of each tank n can be fluidly connected to the second injection and withdrawal system 111. Advantageously, these Vstockn, IF and / or Vstockn, sv selection valves are on / off valves, i.e., open / closed. Preferably, during injection or withdrawal of the storage fluid 5 from a tank n, when one is open, the other is closed.

[0125] According to an example, the first Vstockn, IF and second Vstockn, sv selection valves are positioned downstream of the first pipe 11 and upstream of the second pipe 12, in the direction of flow of the storage fluid, and preferably via the third pipe 13. The third pipe 13 is therefore positioned between the first Vstockn, IF and second Vstockn, sv selection valves, and the first 11 and second pipe 12.

[0126] The recovery unit 10 advantageously includes a VSV-Q valve arranged on the storage circuit, preferably downstream of the flow meter 109. The VSV-Q valve is designed to control the flow rate of the storage fluid in the storage circuit. Note that the flow meter 109 may not be present in the recovery unit 10, particularly in an industrial version of the unit.

[0127] Following an example of this energy recovery unit providing an industrial-scale thermal storage solution, a single VSV-Q flow control valve can be used for both the storage circuit and the cooling water. This means that a single valve regulates the flow of heat transfer fluid circulating in the heat exchanger 102 of the sterilizer 200, whether from the storage circuit or from a cooling water supply 302. This dual use of the VSV-Q flow control valve is possible because the storage circuit and the cooling water supply 302 are decoupled and do not operate simultaneously on the same sterilizer 200. The inherent advantage of this shared use of the VSV-Q flow control valve is the savings from purchasing an additional (and costly) control valve, thus reducing the investment cost of the thermal storage solution.

[0128] Similarly, the flow meter 109 can be used to measure the flow rate of water supplying the heat exchanger 102 from either the storage circuit or the cooling water inlet 302. According to this possibility, the storage circuit includes downstream of the pump 107 the flow meter 109, then a connection of a cooling water inlet branch 302 ensuring the cooling water inlet 302 and then the VSV-Q control valve.

[0129] The recovery unit according to the invention advantageously comprises thermal instrumentation including thermometers for measuring the temperature of the storage fluid at various points within the recovery unit. Preferably, the thermal instrumentation also includes thermometers for measuring the temperature of the sterilization fluid entering and exiting the heat exchanger 102, and returning to or flowing towards the sterilizer 200. In the figures, the thermometers of the thermal instrumentation are designated either T s tock for thermometers concerning storage fluid 5 or Ts™ for thermometers concerning sterilization fluid.

[0130] Advantageously, to guarantee its autonomy, the thermal storage circuit 101 is equipped with its own pump 107 ensuring the circulation of the storage fluid. Advantageously, the recovery unit can operate with a single pump 107, even in the case of a shared recovery unit 10 with several sterilizers 200. Indeed, since the storage circuit 101 operates in a closed loop, all the extracted flow is reinjected.

[0131] According to one possibility, to maintain the operation of pump 107 at its nominal speed, despite variations in the storage fluid flow rate, the storage circuit includes a bypass branch 106 providing a bypass routing of the storage fluid. Advantageously, the circulation of the storage fluid in the bypass branch 106 is regulated by valve Vb. yframing the pump 107 preferably at its terminals. Alternatively, the pump 107 can be equipped with a frequency inverter which can be used to control the flow rate of the storage fluid circulating in the storage circuit by varying the rotational speed of the pump.

[0132] Given the potentially high temperature of the storage fluid charged into tanks 110, 120, 130, 140, which can approach the evaporation temperature of the storage fluid, such as 100°C for water at atmospheric pressure, as an example, the recovery unit advantageously includes a pressurization system 400 for the storage module 100. The pressurization module 400 is configured to pressurize tanks 110, 120, 130, 140 in order to maintain the storage fluid, and in particular superheated water, in a liquid state.

[0133] To address the issue of the variable water level in tanks 110, 120, 130, and 140, which could lead to tank depressurization during discharge, the pressurization module 400 is configured to pressurize the free surface of the storage fluid 5 using, for example, a gas such as air or nitrogen. The pressurization module 400 is advantageously installed and connected to the top of each tank 110, 120, 130, and 140 to maintain sufficient pressure, essential for keeping the storage fluid, and in particular the superheated water, in a liquid state.

[0134] The 400 pressurization module is configured to operate preferentially as a communicating vessel system. To this end, the 400 pressurization module includes a gas circuit connecting all the tanks 110, 120, 130, and 140, preferably via their upper sections, to maintain a homogeneous pressure in each tank, regardless of their storage fluid level. To limit the transfer of storage fluid from one tank to another via this circuit, the 400 pressurization module may include, in a variant not shown, an automatic drain valve located between the top of each tank and the pressurizing gas circuit. Another example of a 400 pressurization system is illustrated in Figures 2 to 4, 9, and 10. The illustrated 400 pressurization system is more simplified than the one shown previously.In the figures, the illustrated pressurization system 400 does not include a rupture disc, which is an additional safety component fitted to the pressurization system. The pressurization system 400 is configured for use with the illustrated 10 recovery units.

[0135] According to one embodiment, the valorization unit 10 according to the invention comprises a mass flow meter 109 (m sThe storage fluid flow meter 109 is arranged on the storage circuit 101, more preferably on the second branch 105 of the circuit and more preferably downstream of the pump 107. The flow meter 109 measures the flow rate of the storage fluid circulating in the storage circuit 101 and intended to supply the heat exchanger 102. In this case, the flow rate of the storage fluid is advantageously regulated according to the temperature measurements at the terminals of the heat exchanger 102 so that the setpoint temperature of the sterilizing fluid is reached at the outlet of the heat exchanger 102 (TSTWJO). According to another embodiment, the control of the storage fluid flow rate does not require the use of a flow meter. This control method is based on evaluating the efficiency of the heat exchanger 102 based on temperature measurements at its terminals and on the setpoint temperature that the sterilization fluid must reach at the outlet of the heat exchanger (TSTWJO).A correlation between the efficiency of the heat exchanger 102 and the flow rate of the storage fluid has been established. This relationship, which correlates the efficiency of the heat exchanger 102 with the flow rate of the storage fluid, is based on the fact that the flow rate is very high and constant (for example, 265 m). 3 The flow rate ( / h) of the sterilizing fluid in the sterilization circuit 201 implies that the limiting thermal resistance is always located on the side of the storage circuit 101 when it is in use. It is therefore possible to control the flow rate of the storage fluid, and thus the thermal power transferred, by evaluating the efficiency of the heat exchanger 102 based on the temperatures measured at its terminals and the setpoint temperature that the sterilizing fluid must reach at the outlet of the heat exchanger (TSTWJO).

[0136] According to an advantageous option, the recovery unit includes at least two isolation valves V s The M-ISO storage circuit 101 is isolated from the heat exchanger 102. The M-ISO Vstock isolation valves are advantageously arranged on the storage circuit 101, one on the first branch 104 and the other on the second branch 105. Preferably, the MI Vstock isolation valves SO are arranged at the terminals of the heat exchanger. These valves are configured to ensure the isolation of the storage circuit 101 and therefore stop the circulation of the storage fluid in the heat exchanger 102 in particular with the aim of allowing the circulation in the heat exchanger 102 of a cold source or a hot source coming in as a replacement for the storage fluid 5. Advantageously, these Vstock M-ISO valves are on / off, open / closed valves.

[0137] Preferably, Vstock M-ISO isolation valves are robotized and controlled by a management module.

[0138] In one embodiment, the recovery unit includes a thermal energy management module. The management module is configured to ensure optimal recovery of the thermal energy intended for at least one sterilizer 200. The management module preferentially controls the isolation valves of the tanks V s tock-from and V s tock-to as well as the isolation valves of the 101 Vstock MI storage circuit SOIn one scenario, the control module evaluates the efficiency of the heat exchanger 102 based on the temperatures measured at its terminals and the setpoint temperature that the sterilizing fluid must reach at the heat exchanger outlet (TSTWJO). In this case, the control module advantageously operates a pump 107 equipped with a variable frequency drive (VFD), which can be adjusted to control the flow rate of the storage fluid circulating in the storage circuit by varying the pump's rotational speed. In another scenario, the control module operates the VSV-Q valve, which modulates the flow rate of the storage fluid at the inlet of the sterilizer 200.The management module collects information from the recovery unit through various instruments, such as the flow rate of the storage fluid circulating via the flow meter 109, and / or the temperatures of the storage fluid and / or the sterilization fluid via the thermal instrumentation described above.

[0139] The control module is designed to maintain a set temperature to ensure the correct operation of sterilizer 200. A predefined set temperature is used. Preferably, this set temperature is that of the sterilizing fluid exiting the heat exchanger 102 (Ts-rw.to). Alternatively, this set temperature may vary depending on the operating phase of sterilizer 200. The set temperature follows a scale that corresponds to the operating cycle of sterilizer 200.

[0140] The management module thus controls the flow rate of the storage fluid (m stock) circulating advantageously in a closed loop in the storage circuit 101 by modulating the VSV-Q regulating valve.

[0141] Advantageously, the management module ensures the control of the isolation valves of the tanks and the selection valves of the first 108 or second 111 injection and withdrawal system, according to the temperature of the storage fluid contained in said tanks and the thermal energy requirements of the sterilizer 200. The management module can control the order of storage and destocking of the storage fluid from the tanks.

[0142] The sterilization device illustrated in Figures 2 to 4, 9, and 10 includes a common section shown on the right side of all the figures and described below. The sterilization device comprises a sterilizer 200 supplied with a sterilizing fluid that advantageously circulates in a closed loop within a sterilization circuit 201 between the heat exchanger 102 and the sterilizer 200. The sterilization circuit 201 advantageously includes a pump 202 and optionally a mass flow meter 203. The heat exchanger 102 includes an inlet 204 and an outlet 205 for the sterilizing fluid and an inlet 206 and an outlet 207 for a hot or cold source, as required. In an advantageous configuration, the hot source is either steam from a heating means, such as a boiler, or a storage fluid.Similarly, the cold source is either cooling water from a water network, or the storage fluid.

[0143] The figures therefore illustrate a cooling water inlet 302, a steam inlet 301 connected to the inlet 206 of the heat exchanger 102 and a cooling water outlet 303 and a condensate outlet 304 connected to the outlet 207 of the heat exchanger 102.

[0144] A properly sized, designed, and operated energy recovery unit would allow for the recovery, under steady-state conditions, of approximately 30% of the thermal energy required for the heating phase and the thermal energy required to dissipate heat during the cooling phase of the sterilization process. This would be achieved by recovering and storing the waste heat extracted from the sterilizer 200 during the cooling phase of the preceding cycle. Such a solution could be profitable over very short periods, for example, less than 3-4 years, particularly if the sterilization process to which it is coupled performs a large number of cycles per day, for example, more than 5 cycles per day. Furthermore, profitability would be even greater since the energy recovery unit would allow for the recovery of a larger quantity of energy per cycle compared to existing solutions.

[0145] The energy recovery unit according to the invention allows for the recovery of a quantity of thermal energy between sterilization cycles, thereby reducing the amount of steam and cooling water consumed, and also contributes to increasing the availability of utilities (steam, cooling water). Indeed, when autoclaves or sterilizers are heated or cooled by the energy recovery unit, they do not draw on the steam or cooling water networks, consequently increasing their capacity and availability for other autoclaves (sterilizers or equipment) not supplied by the energy recovery unit. This advantage will be particularly beneficial in installations experiencing utility congestion, which limits either the number of devices that can be powered in parallel or the rate of temperature increases and decreases (ramps – following the schedule).Furthermore, in the case of installing additional autoclaves - sterilizers on existing networks, the integration of a recovery unit could possibly limit, or even avoid, the investment in additional heating and / or cooling means to supply them.

[0146] The invention relates to a method for recovering thermal energy using a recovery unit as described above. The recovery method advantageously comprises a discharge stage alternating with a charging stage.

[0147] The charging of storage module 100 corresponds to the storage of the storage fluid that has recovered thermal energy at the heat exchanger 102. This charging stage of storage module 100 corresponds to the cooling phase of sterilizer 200. During this cooling phase, sterilizer 200 and its contents are cooled by the circulation of the sterilization fluid, which is cooled at the heat exchanger 102 through heat exchange with a cold source, which can be cooling water or the storage fluid. In the case of a charging stage of storage module 100, it is indeed the storage fluid that circulates in the heat exchanger 102 to exchange heat with the sterilization fluid, thus ensuring the cooling of the sterilization fluid.At the beginning of the charging phase, i.e., at the end of the discharging phase, the storage module 100 contains storage fluid, with the exception of the buffer volume, which advantageously corresponds to a tank 110, 120, 130, or 140 that is kept empty. The tank(s) containing the storage fluid are either fully or partially filled. Preferably, if the storage module 100 includes more than two tanks 110, 120, 130, or 140, their levels are identical due to the principle of communicating vessels. Optimal energy recovery does not necessarily require filling the tanks to their maximum volume, except for the buffer volume. This is particularly true at startup when the storage fluid initially contained in the tanks is close to ambient temperature. The storage fluid contained in each tank 110, 120, 130, 140 is advantageously at a nearly homogeneous temperature throughout the entire volume of the tank 110, 120, 130, 140.

[0148] The charging stage, illustrated for example in Figures 3 and 9 according to two variants, comprises the withdrawal of the storage fluid 5 from a storage tank 110, 120, 130, or 140, such as, for example, the second storage tank 120. The storage fluid 5 is withdrawn by the second storage fluid injection and withdrawal system 111, at the storage fluid 50 fill level in the tank 120 to be emptied. The withdrawal thus follows the thermal stratification of the storage fluid 5 in the tank to be emptied, from the warmest temperature to the coldest temperature. The storage fluid 5 is recovered by the storage circuit 101, more specifically the second branch 105, ensuring the circulation of the storage fluid towards the heat exchanger 102. In one example, the valve V s tock2-from is open, while the other V valves s The locks can be closed. The V valve stock2-sv is then open, while valve V s tock2-iF is closed.

[0149] Sampling can begin with tanks 110, 120, 130, and 140, where the storage fluid has the highest temperature. Sampling then proceeds in descending order of temperature, from hottest to coldest. This improves monitoring of the decreasing temperature curve for cooling sterilizer 200.

[0150] The charging stage advantageously comprises, simultaneously, the injection of the storage fluid 5 into a storage tank 110, 120, 130, 140, preferably different from the storage tank 110, 120, 130, 140 from which the storage fluid is withdrawn, and for example, the first storage tank 110. The storage fluid is injected into the buffer volume. Preferably, the tank 110, 120, 130, 140 intended to receive the storage fluid corresponds to the tank forming the buffer volume. The tank 110, 120, 130, 140 intended to receive the storage fluid is advantageously empty. The storage fluid is injected into the lower part 110b of tank 110 by the first injection and withdrawal system 108.The storage fluid 5 arrives increasingly cold, allowing for thermal stratification by maintaining the warmest storage fluid from the initial cooling of sterilizer 200 in the upper part and the coldest injected storage fluid 5 in the lower part. For example, in the case of filling the first tank 110, valve V. s tocki-to is open, while the other V valves s The tockn-to valves can be closed. The Vstocki-irest valve then remains open, while the V valve s tocki-sv is closed.

[0151] The discharge of storage module 100 corresponds to the release of the storage fluid, transferring its thermal energy to the heat exchanger 102. This discharge stage of storage module 100 corresponds to the heating phase of sterilizer 200. During this heating phase, sterilizer 200 and its contents are heated by the circulation of the sterilization fluid, which is heated through the heat exchanger 102 by exchanging heat with a hot source, which can be steam or the storage fluid. In the case of a discharge stage of storage module 100, it is indeed the storage fluid that circulates through the heat exchanger 102 to exchange heat with the sterilization fluid to ensure its heating.

[0152] At the beginning of the discharge stage, i.e., at the end of the charging stage, the tanks contain storage fluid, with the exception of the buffer volume, advantageously corresponding to a tank 110, 120, 130, or 140, which is kept empty. The tanks 110, 120, 130, and 140 containing storage fluid are either fully or partially filled. Preferably, if the storage module 100 comprises more than two tanks 110, 120, 130, or 140, their levels are identical, due to the principle of communicating vessels. The storage fluid in each tank is advantageously temperature stratified.

[0153] The discharge of storage module 100 is advantageously carried out using a procedure that limits the alteration of the thermal stratification established in the previously charged tanks 110, 120, 130, and 140, thus preventing the degradation of the thermal energy contained in each of them. Unlike the charging process, during discharge, as illustrated for example in Figures 4 and 10 in two variations, the filled tanks 110, 120, 130, and 140 that make up storage module 100 are emptied to supply the heat exchanger 102 coupled to the sterilizer 200, starting with the tank containing the lowest-temperature storage fluid and then proceeding in ascending order of temperature up to the tank 110, 120, 130, and 140 storing the highest-temperature storage fluid.Advantageously, tanks 110, 120, 130, 140 containing a stratified storage fluid at a higher temperature are reserved for the end of the discharge at the time when the heating of the sterilizer 200 requires increasingly higher sterilization fluid temperatures.

[0154] The discharge stage includes withdrawing the storage fluid from a storage tank 110, 120, 130, or 140, such as, for example, the first storage tank 110. The storage fluid 5 is drawn from the lower part 110b by the first storage fluid injection and withdrawal system 108. The storage fluid from tanks 110, 120, 130, or 140 is temperature stratified and is thus recovered from coldest to warmest by the first injection and withdrawal system 108. The storage fluid 5 is recovered by the storage circuit 101, more precisely by the second branch 105 towards the heat exchanger 102. In one example, the Vstocki-from valve is open, while the other V valves s The locks can be closed. The V valve s tocki-iF is then opened, while the V valve s tocki-sv is closed.

[0155] During the discharge stage, if several tanks are filled with storage fluid, the tank with the lowest storage fluid temperature (110, 120, 130, 140) is discharged first. The fluid is then drawn sequentially from the tanks in ascending order of temperature. The storage fluid with the highest temperature is reserved for the end of the discharge process, when heating the sterilizer (200) requires increasingly higher sterilization fluid temperatures.

[0156] The discharge step advantageously includes simultaneously injecting the storage fluid into a storage tank 110, 120, 130, 140, preferably different from the storage tank from which the storage fluid is withdrawn, and for example, the second storage tank 120. The storage fluid is injected into the buffer volume. Preferably, the tank 110, 120, 130, 140 intended to receive the storage fluid corresponds to the tank 110, 120, 130, 140 forming the buffer volume. The tank intended to receive the storage fluid is advantageously empty.

[0157] The storage fluid 5 is advantageously injected by the second storage fluid 5 injection and withdrawal system 111 at the storage fluid 5 filling level 50 in the tank to be filled. The increasingly hot storage fluid 5 can therefore be injected into the tank to be filled in such a way as to follow the natural thermal stratification of the storage fluid 5 within the tank. This optimizes the thermal stratification in the tank to be filled, thereby maximizing the reuse of the stored thermal energy for the subsequent charging phase. For example, in the case of filling the second tank 120, the valve V s tock2-to is open, while the other V valves s The tapn-to valves can be closed. The V valve s tock2-sv is then open, while valve V s tock2-iF is closed.

[0158] Example of load of storage module 100 of the recovery unit.

[0159] As illustrated in Figures 3 and 9, for example, the loading step of storage module 100 takes place during the sterilizer's cooling phase. At the beginning of the loading step of storage module 100, the four tanks 110, 120, 130, and 140 can each contain storage fluid at a different temperature, either homogeneously or stratified. In the example shown, tank 140 contains storage fluid at the highest homogeneous temperature (relative to the other tanks), while tank 130 contains storage fluid at the lowest homogeneous temperature. For example, tank 130 is at a nearly homogeneous temperature of 45°C. Tank 140 is at a nearly homogeneous temperature of 85°C. Tanks 110 and 120 can be temperature stratified. The average temperature of tank 120 can be lower than the average temperature of tank 110.

[0160] The charging of storage module 100 can begin with a step of drawing storage fluid from the tank with the highest temperature. This can be the hottest tank 140 or directly the temperature-stratified tank 120, depending on the match between the storage fluid temperature in each tank and the expected temperature setpoint.

[0161] The withdrawal process begins with a flow of storage fluid necessary to cool the sterilizer 200 according to a predefined temperature setpoint. Simultaneously with the withdrawal step, the injection step begins. This flow of storage fluid, which is heated during its passage through the heat exchanger 102 coupled to the sterilizer 200, is then injected into the buffer volume, for example, the tank 110. The tank 110 is filled from its lower section, advantageously by the injection and withdrawal system 108, and preferably, if present, by a system that distributes and evens out the flow rate over the entire hydraulic cross-section of the tank.The bottom-filling system of the storage tank allows for temperature stratification of the injected storage fluid. The hottest storage fluid, resulting from the initial cooling of sterilizer 200, remains in the upper portion, while the coldest storage fluid is advantageously injected until tank 110 is completely filled. When tank 120 is empty or its internal temperature is no longer sufficient to cool sterilizer 200 at the maximum permissible flow rate in the storage circuit 101, another tank containing a storage fluid at a lower temperature than the storage fluid in tanks 120 and 110 is used. In Figures 3 and 9, for example, tank 130 would then take over.If tank 110 is full, the heated storage fluid is injected into the buffer volume, i.e., advantageously the empty tank 120, using the same procedure as for filling tank 110, so as to control thermal stratification of the storage fluid filling the tank. The final stage of charging storage module 100 is completed by temperature-stratified refilling of tank 110, drawing from tank 130, which is advantageously initially at a homogeneous temperature. During the charging phase of storage module 100, the selection of tanks 110, 120, 130, and 140 from which fluid is drawn and the tanks from which fluid is supplied is carried out via the tank isolation valves, which are advantageously controllable, in particular, by a management module.When the entire storage module 100 is loaded or when its condition no longer allows the cooling of the sterilizer 200 to be ensured, the isolation valves of the storage circuit 101 V. s tock,M-iso, isolate the storage circuit 101 from the heat exchanger 102 coupled to the sterilizer 200, before the network of another cold source such as cooling water takes over through the inlet 302.

[0162] Advantageously, the withdrawal step from tanks 110, 120, 130, and 140, initially at different homogeneous or average temperatures, is always preferably carried out starting with the tank at the highest temperature and proceeding in descending order down to the tank at the lowest temperature. If the internal homogeneous or average temperature of the discharged tank 110, 120, 130, or 140 is too high to ensure the cooling of the sterilizer 200, the next tank in descending order of temperature takes over.

[0163] At the end of the charging stage, at least one tank 110 can be filled with temperature-stratified storage fluid. For example, all three tanks 110, 130, and 140 can be filled with temperature-stratified storage fluid. Specifically, tank 130 contains storage fluid with a temperature ranging from 50°C to 70°C from bottom to top, tank 110 contains storage fluid with a temperature ranging from 70°C to 90°C from bottom to top, and tank 140 contains storage fluid with a temperature ranging from 90°C to 110°C from bottom to top. These conditions represent an optimal operating scenario that results in the complete discharge of each of the initially charged tanks. In a less favorable scenario, the temperature of the storage fluid in one or more of the tanks prevents their complete discharge. The tank acting as a buffer for the next discharge will not initially be completely empty.This mode can be described as a degraded mode.

[0164] Example of a discharge from storage module 100:

[0165] As illustrated in Figures 4 and 10, for example, the discharge step of storage module 100 takes place during the heating phase of sterilizer 200. In one example, the temperature-stratified tank 110 can be discharged, provided that the temperature of the storage fluid drawn from its lower section is sufficient to meet the set temperature requirement for the sterilizing fluid exiting sterilizer 200. stw,to. Otherwise, discharge begins with the next tank that meets this temperature condition, in ascending order of temperature. Assuming the temperature condition of tank 110 is met, the storage fluid feeds the heat exchanger 102 before being injected, cooled, into the buffer volume, i.e., an advantageously empty tank, in this case tank 120, which may initially be empty. The injection of the cooled storage fluid into tank 120 is carried out by the second injection and withdrawal system 111. Preferably, if present, it passes through a system that distributes and evens out the flow rate over the entire hydraulic cross-section of the tank. During this discharge phase of the storage module 100, the storage fluid injected into the tanks arrives at an increasingly higher temperature.The use of the second injection and withdrawal system allows for monitoring the natural stratification of the storage fluid 5 in tank 120. As soon as tank 110 is completely emptied, or following the premature cessation of its withdrawal to maintain the set temperature of the sterilizing fluid sent to the sterilizer 200, tank 140 can take over. The flow of storage fluid withdrawn from tank 110 and cooled after passing through the heat exchanger 102 then feeds tank 120. The operating procedure then proceeds during this phase of utilizing the stored thermal energy until, if possible, the complete discharge of tank 140, which contains a volume of stratified or unstratified storage fluid at the highest temperature level.

[0166] Note that other variations are possible. The recovery unit 10 may include a pump equipped with a frequency inverter, which can be used to control the flow rate of the storage fluid circulating in the storage circuit by varying the pump's rotational speed. The recovery unit includes a PID control module connecting the temperature probe T s stock - from 1, the VstockM-iso valves, and possibly the water supply. The flow rate of the heat transfer fluid 5 circulating in the recovery unit 10 is regulated by acting on the pump's speed controller, which is managed by the PID based on the temperature measurement T sThe flow rate measurement by the flow meter can also be taken into account for PID control. In another example, the control setpoint could be to adjust the pump speed to increase the output flow rate, in order to satisfy the setpoint for the measured temperature TSTW,to, without necessarily needing to measure the flow rate.

[0167] The recovery unit may include a pump and a flow meter. The recovery unit may include a VSV-Q valve for flow regulation, advantageously positioned upstream of the flow meter and downstream of the pump. The recovery unit includes a PID control module connecting the pump, the VstockM-iso valve, the flow meter, and optionally, the water makeup system. The flow rate of the storage fluid circulating within the recovery unit is regulated by the VSV-Q control valve, which is controlled by the PID controller for temperature measurement TSTWJO. The flow measurement from the flow meter 109 can also be used for PID control. Here again, in another example, the control setpoint could be to increase the pump speed to boost the output flow rate, thereby satisfying the setpoint for the measured temperature TSTW, to, without necessarily needing to measure the flow rate.Flow rate is a parameter that can be controlled by the PID and not necessarily a setpoint.

[0168] The sterilization device includes a recovery unit which may include a plurality of heat exchangers 102, for example three heat exchangers 102, each respectively associated with a sterilizer 200. The three heat exchangers 102 can be arranged in parallel, on the second branch 105 and on the first branch 104.

[0169] The second injection and withdrawal system 111 is now described in more detail with reference to Figures 5 to 8 and 11. It is considered, for the sake of completeness, that this system 111 is carried by the tank 110. This can of course be applied to each tank comprising the second injection and withdrawal system 111.

[0170] To adapt the injection or withdrawal of the storage fluid 5 to the fill level 50, the second injection and withdrawal system 111 includes a body 1110 that is movable along the vertical direction z within the tank to be emptied or filled. As illustrated, for example, in Figures 5 to 8, the body 1110 is configured to have a height H1 along the vertical direction z, the height H1 varying according to the fill level 50 of storage fluid 5. The body 1110 can, in particular, be configured to contract or extend along a principal extension direction substantially parallel to the vertical direction z, and preferably telescopically. The body 1110 can therefore move between a retracted configuration and a maximum extended configuration, passing through several extended configurations depending on the fill level 50.Preferably, the 1110 body is mobile only in translation between its retracted and deployed configurations. Preferably, the deployment direction of the 1110 body is centered on the central longitudinal axis of the tank, parallel to the vertical z direction.

[0171] For example, the 1110 body is deployable or retractable to at least 10%, preferably at least 20%, preferably at least 30%, preferably at least 50%, and preferably at least 80%, of the tank height. As an example, the 1110 body is deployable or retractable to the upper or lower base of the tank shell.

[0172] According to one example, the 1110 body includes coaxial telescopic tubes 1110a, configured to slide telescopically between each other to move the 1110 body between its retracted and deployed configurations.

[0173] As illustrated in Figures 5 and 8, the body 110 has an increasing internal hydraulic cross-sectional area S from the point of connection to the fluidic circuit 101 (smallest cross-section) to the injection and withdrawal module 1111 (largest cross-section). The internal hydraulic cross-sectional area S is perpendicular to the main direction of deployment of the body 1110, and therefore, for example, the cross-sectional area S is essentially horizontal. This arrangement allows for a gradual reduction in the flow velocity of the storage fluid 5 up to the point of hydraulic injection or withdrawal, which is more favorable for controlling thermal stratification within the reservoir.For this purpose, the coaxial tubes 1110a may have at least one internal dimension, for example a diameter, increasing along the body 1110 from the coaxial tube on the side of the connection point to the fluidic circuit 101, of smaller dimension, to the coaxial tube on the side of the injection and withdrawal module 1111, of larger dimension.

[0174] As an alternative to coaxial tubes, the 1110 body may include a flexible, preferably retractable, tube.

[0175] According to an example illustrated in Figures 5 and 6, the second injection and withdrawal system 111 is fluidically connected to the fluidic circuit 101 via the upper part 110a of the tank 110. In this example, the retracted configuration corresponds to the maximum filling of the tank 110, which can then be full or partially filled, as illustrated in Figure 6, with the body then having a height H2. Figure 5 illustrates a deployed configuration in which H1>H2, during the filling or withdrawal of the tank 110. Preferably, the maximum deployed configuration corresponds to the minimum filling of the tank 110, which can then be empty or partially filled. If present, the connection of the pressurization module 400 is preferably also positioned in the upper part 110a of the tank 110, near the hydraulic connection with the body 1110.

[0176] According to an alternative example illustrated in Figures 7 and 8, the second injection and withdrawal system 111 is fluidically connected to the fluidic circuit 101 via the lower part 110b of the reservoir 110. This, however, implies the presence of an element that can be a thermal conductor within the temperature-stratified water volume. In this example, the retracted configuration corresponds to the minimum filling of the reservoir 110, which can then be empty or partially filled, as illustrated in Figure 7, with the body 1110 having a height H2. Figure 8 illustrates a deployed configuration in which H1>H2, during the filling or withdrawal of the reservoir 110. Preferably, the maximum deployed configuration corresponds to the maximum filling of the reservoir 110, which can then be full or partially filled.The connection of the first injection and withdrawal system 108 is then also located in the lower part 110b of the tank 110, near the hydraulic connection with the body 1110. For example, the first injection and withdrawal system 108 is arranged radially around the hydraulic connection with the body 1110.

[0177] The injection and withdrawal module 1111 of the storage fluid 5 is fluidly connected to the body 1110. During an injection, the storage fluid 5 therefore flows into the body 1110 to be injected into the tank 110 by the injection and withdrawal module 1111. During a withdrawal, the storage fluid 5 is taken by the injection and withdrawal module 1111 and then flows into the body 1110 to be circulated in the storage circuit 101.

[0178] As illustrated in Figures 5 to 8, the injection and withdrawal module 1111 may include a flotation device 1112. The flotation device 1112 passively tracks changes in the fill level 50 of the storage fluid 5 contained in the tank 110. The vertical displacement z of the flotation device 1112 as a function of the fill level 50 can induce, preferably on its own, the contraction or expansion of the body 1110. The flotation device thus ensures that the hydraulic injection or withdrawal occurs just below or at the level of the free surface of the storage fluid 5 contained in the tank 110.

[0179] As an example, for the first injection and withdrawal system 108, the storage module 100 includes a system for homogenizing and distributing the flow of the injected storage fluid throughout the hydraulic cross-section of the tanks 110, 120, 130, and 140. For instance, a system for homogenizing and distributing the flow of the storage fluid may include advantageously sized devices designed to uniformly distribute the flow of the storage fluid injected into and withdrawn from the tank over a larger hydraulic cross-section, thereby reducing its flow velocity within the tank. Indeed, the higher the flow velocity, the greater the resulting hydraulic mixing, which is highly detrimental to the formation and maintenance of thermal stratification within the storage volume.These devices include, for example, hydraulic deflectors whose shape can be designed to ensure good orientation and distribution of the flow in the tank while reducing its flow velocity.

[0180] Such systems may be provided as an alternative or complement to the second injection and withdrawal system 111. In order to obtain a more homogeneous distribution of the velocity profile of the injected or withdrawn storage fluid flow rate 5, the aim is to limit the temperature mixing phenomenon between the volume of the storage fluid 5 contained in the tank at the injection or withdrawal point and the injected or withdrawn storage fluid flow rate. To this end, the injection and withdrawal module can be configured to withdraw and inject the storage fluid radially in a plane substantially parallel to, and preferably coinciding with, the plane of the free surface of the storage fluid 5, and for example in a plane substantially perpendicular to the deployment direction of the body 1110, and therefore preferably in a substantially horizontal plane.The term "radial" can be understood in relation to the cross-section in the (x,y) plane of a tank, for example of cylindrical shape.

[0181] For this purpose, the injection and withdrawal module 1111 can comprise at least two plates 1111a, 1111c, for example, flat or pavilion-shaped. The transverse dimension, for example the diameter, and / or the inter-plate spacing D can be advantageously dimensioned to optimize the formation and maintenance of thermal stratification. As an indication, for a storage tank of a few m³ 3Considering an injection or withdrawal point based on a double-plate design, the characteristic dimensions could be on the order of 200 mm for the plate diameter and on the order of ten millimeters for the inter-plate spacing (D). Of course, these characteristic dimensions are illustrative, as they depend specifically on the hydraulic (flow rate) and thermal conditions of the storage fluid (temperature of the contained fluid and the injected or withdrawn fluid), as well as the dimensions of the reservoir, and are based on the most representative dimensionless numbers in this field, such as the Richardson number and the Froude number.

[0182] Figures 9 and 10 represent P&ID diagrams respectively in charge and discharge of the storage module 100, according to the variant in which the second injection and withdrawal system 111 is fluidly connected to the circuit 101 by the lower part 110b of the tanks 110, 120, 130, 140.

[0183] For example, and particularly when the body 1110 comprises coaxial tubes that slide telescopically relative to each other, the body 1110 may include a rotation-locking device 1110b. The locking device 1110b may be configured to prevent the relative rotation of the coaxial tubes, thus locking them together. The body 1110 is therefore only mobile in its deployment direction, preferably the vertical direction z. To this end, as illustrated in Figure 11, this rotation-locking guiding device 1110b may include profiled elements, for example, needles, that facilitate the translational guidance of the coaxial tubes 1110a, ensuring their centering and preventing their rotation. The coaxial tubes may have additional grooves 1110ab to accommodate these elements. The grooves are preferably formed longitudinally on the outer wall of the inner tube and on the inner wall of the outer tube.The grooves of two coaxial tubes are positioned opposite each other. The needle / groove pairs are preferably distributed radially at the vertices of a polygon centered on the deployment axis of the body 1110. The locking device 1110b preferably comprises at least three needles. Stops at the ends of the grooves 1110ab or the coaxial tubes 1110a may be added to prevent the coaxial tube assembly from separating or the needles from coming out of their housing.

[0184] Following another example, a coaxial tube, for example one coaxial tube out of two, and in particular the inner tube, may be provided with a protrusion along the longitudinal axis on its outer wall, while the tube opposite, in this case the outer tube, may be provided with a groove along the longitudinal axis on its inner wall, sized to accommodate the protrusion of the inner tube.

[0185] The invention is not limited to the embodiments described above and extends to all embodiments covered by the invention. The present invention is not limited to the examples described above. Many other embodiments are possible, for example, by combining features described above, without departing from the scope of the invention.

[0186] For example, as an alternative to a passive flotation device, an active electrical system, operating for example with a worm screw, can be provided to modify the height of the body of the second injection and withdrawal system.

[0187] The loading and unloading steps are illustrated above with reference to certain tanks that are being emptied or filled. The tanks are designated for illustrative purposes. A different order of filling and / or emptying is possible, particularly depending on the temperature schedule to be followed and the temperature of the storage fluid, whether stratified or not, in each tank.

[0188] It can also be expected that the storage fluid will be temperature stratified throughout all the tanks of the storage module.

[0189] LIST OF REFERENCES

[0190] 11. First driving

[0191] 12. Second driving

[0192] 13. Third driving

[0193] 100. Storage Module

[0194] 101. Storage circuit

[0195] 102. Heat exchanger

[0196] 103. Water refill

[0197] 104. First branch

[0198] 105. Second branch

[0199] 106. Branch off

[0200] 107. Pump

[0201] 108. First injection and withdrawal system

[0202] 109. Flow meter

[0203] 110. Reservoir

[0204] 110a. Upper part

[0205] 110b. Lower part

[0206] 111. Second injection and withdrawal system

[0207] 1110. Body

[0208] 1110a. Coaxial telescopic tubes

[0209] 1110ab. Groove

[0210] 1110b. Rotation locking system

[0211] 1111. Injection and withdrawal module

[0212] 1111a. Plate

[0213] 1111b. Plate

[0214] 1111c. Inter-plate spacing

[0215] 1112. Flotation device

[0216] 120. Reservoir

[0217] 130. Reservoir

[0218] 140. Reservoir

[0219] 200. Sterilizer

[0220] 201. Sterilization circuit

[0221] 202. Pump

[0222] 203. Flow meter 204. Sterilization fluid inlet to the heat exchanger 102

[0223] 205. Sterilization fluid outlet from exchanger 102

[0224] 206. Entrance to a hot or cold spring

[0225] 207. Outlet of a hot or cold spring

[0226] 301. Steam arrival

[0227] 302. Cooling water inlet

[0228] 303. Cooling water return

[0229] 304. Condensate return

[0230] 400. Pressurization Module

[0231] 5. Storage fluid

[0232] 50. Fill level

Claims

DEMANDS 1. Valuation unit (10) comprising: • a heat exchanger (102), • a thermal energy storage module (100) configured to receive a storage fluid (5), the storage module comprising at least two tanks (110, 120), each intended to receive the storage fluid (5) and each comprising a first injection and withdrawal system (108) for the storage fluid arranged in the lower part (110b) of said tank (110, 120), the first injection and withdrawal system (108) being configured to draw and inject the storage fluid (5) into the lower part of said tank (110, 120), the storage module (100) further comprising an empty volume referred to as a buffer volume, the storage fluid intended to be stored in the storage module (100) representing a volume less than the volume of the storage module (100) so as to maintain the buffer volume, • a thermal storage circuit (101) configured to fluidly connect the storage module (100) and the heat exchanger (102) to ensure the circulation of the storage fluid (5), characterized in that the at least two tanks (110, 120) are intended to have a filling level (50) of storage fluid, separating a filled sub-volume and an empty sub-volume, and in that the at least two tanks (110, 120) each comprise a second injection and withdrawal system (111) of the storage fluid (5), each second injection and withdrawal system (111) comprising: o a body (1110) configured to be at least partially movable in a vertical direction (z) within said tank (110, 120), and o an injection and withdrawal module (1111) of the storage fluid (5) fluidly connected to the body (1110),in order to draw and inject the storage fluid (5) at a variable height depending on the filling level of said storage fluid (110, 120).

2. Valorization unit (10) according to the preceding claim, wherein the body (1110) of at least one, and preferably of each, second injection and withdrawal system (111) has a deployed configuration and a plurality of configurations retracted, so as to modify the length of the body (1110) along the vertical direction z as a function of the level of filling (50) in storage fluid (5).

3. Valorization unit (10) according to the preceding claim, wherein the body (1110) of at least one, and preferably of each, second injection and withdrawal system (111) is telescopic and slides along a principal deployment direction of the body (1110), the body (1110) having an internal hydraulic section (S), taken substantially perpendicular to the principal deployment direction of the body, increasing along the principal deployment direction towards the injection and withdrawal module (1111). Preferably, the body (1110) of said second injection and withdrawal system (111) comprises: • a set of coaxial telescopic tubes (1110a) configured together to slide along the main deployment direction of the body (1110), and • a rotation locking device (1110b), around the main direction of deployment of the body, of the telescopic tubes (1110a) relative to each other.

4. Valorization unit (10) according to any one of the preceding claims, wherein the at least two tanks (110, 120) have an upper part (110a), and wherein the body (1110) of at least one, and preferably of each, second injection and withdrawal system (111) extends from the upper part (110a) of said tank (110, 120) so as to extend mainly into the empty sub-volume.

5. Valorization unit (10) according to any one of the preceding claims, wherein each second injection and withdrawal system (111) is configured to draw and inject the storage fluid (5), by the injection and withdrawal module (1111), at a distance (D) extending into the filled sub-volume from the filling level (50), the distance (D) being between 0 cm and 20 cm.

6. Valorization unit (10) according to any one of the preceding claims, wherein the injection and withdrawal module (1111) of at least one, and preferably of each, second injection and withdrawal system (111) comprises a flotation device (1112).

7. Valorization unit (10) according to any one of the preceding claims, wherein the injection and withdrawal module (1111) of at least one, and preferably of each, second injection and withdrawal system (111) is configured to radially inject or withdraw the storage fluid (5).

8. Valorization unit (10) according to any one of the preceding claims, wherein said injection and withdrawal module (1111) comprises at least two plates (1111a, 1111b) at least partially superimposed along the vertical direction z, the at least two plates (1111a, 1111 b) delimiting a gap (1111c) having rotational symmetry about the vertical direction z and permitting the injection and withdrawal of the storage fluid (5).

9. A recovery unit (10) according to any one of the preceding claims, further comprising, for each of the at least two tanks (110, 120), a first selection valve (Vstockn, IF) fluidly connected to the first injection and withdrawal system (108), a second selection valve (Vstockn, sv) fluidly connected to the second injection and withdrawal system (111), the first and second selection valves being configured to select one of the first (108) and second (111) injection systems for injecting or withdrawing the storage fluid (5), preferably, the thermal storage circuit (101) comprising, for each of the at least two tanks (110, 120), a first conduit (11) for conveying the storage fluid (5) to the inlet of said tank (110, 120) and a second conduit (12) for conveying the storage fluid (5) to the outlet of said tank (110, 120). reservoir (110, 120),and a third pipe (13) forming a common sub-branch to the first (11) and second (12) pipes, and positioned downstream of the first pipe (11) and upstream of the second pipe (12) in the direction of flow of the storage fluid (5), the first (Vstockn, IF) and second (Vstockn, sv) selection valves being fluidly connected to the third pipe (13).

10. Sterilization device comprising a sterilizer (200) and a recovery unit (10) according to any one of the preceding claims, preferably the device further comprises a cold source inlet (302) different from the storage fluid and a hot source inlet (301) different from the storage fluid (5).

11. A method for recovering thermal energy by means of a recovery unit (10) according to any one of claims 1 to 9, the recovery unit (10) receiving a storage fluid (5), the process comprising a step of charging the storage module (100) comprising: • the withdrawal of the storage fluid (5) by the second injection and withdrawal system (111) from one of the at least two storage tanks (110, 120), to a height in said tank depending on the filling level (50) in storage fluid (5), for the circulation of the storage fluid (5) in the storage circuit (101) in order to exchange thermal energy in the heat exchanger (102), • the injection of the storage fluid (5) into the buffer volume, preferably during the withdrawal, the reservoir (110, 120, 130, 140) from which the storage fluid (5) is withdrawn includes the storage fluid (5) exhibiting temperature stratification.

12. Method according to the preceding claim wherein during the injection step, the buffer volume is a reservoir (110, 120) different from the storage reservoir (110, 120) from which the storage fluid (5) is withdrawn, the storage fluid (5) is injected into the lower part (110b) of the reservoir (110, 120) by the first injection and withdrawal system (108) and arrives increasingly colder, ensuring thermal stratification of the storage fluid (5) in the buffer volume.

13. A method for recovering thermal energy by means of a recovery unit (10) according to any one of claims 1 to 9, the recovery unit (10) receiving a storage fluid (5), the method comprising a step of discharging the storage fluid (5) comprising: • the withdrawal, by the first injection and withdrawal system (108), of the storage fluid in the lower part of a storage tank (110, 120), from among the at least two storage tanks (110, 120) for the circulation of the storage fluid in the storage circuit (101) in order to exchange thermal energy in the heat exchanger (102), • the injection of the storage fluid into the buffer volume, preferably during the withdrawal stage, the tank (110, 120) from which the storage fluid is withdrawn includes the temperature-stratified storage fluid, the withdrawal being carried out in the lower part, the sampling begins with the coldest storage fluid and progresses to the warmest.

14. A method according to the preceding claim, wherein during the injection step, the buffer volume is a reservoir (110, 120) distinct from the storage reservoir (110, 120) from which the storage fluid is drawn, and the storage fluid is injected by the a second injection and withdrawal system (111) of said storage tank, at a height in said tank that is a function of the storage fluid filling level, and arrives increasingly hot and is thermally stratified as the storage fluid is injected into said tank.

15. A method according to any one of the four preceding claims, wherein the recovery unit (10) further comprises, for each of the at least two tanks (110, 120), a first selection valve (Vstockn, IF) fluidly connected to the first injection and withdrawal system (108), and a second selection valve (Vstockn, sv) fluidly connected to the second injection and withdrawal system (111), the method further comprising a selection of the injection and withdrawal system to be used, from among the first (108) and second (111) injection and withdrawal systems.

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