Method for carrying out cyclic energy storage and device therefor

Description

[0001] The invention relates to a method for carrying out cyclic energy storage with the features of claim 1 and a device therefor with the features of claim 14.

[0002] According to the known state of the art, energy storage methods and corresponding devices are used and required wherever heat is generated and transferred to a fluid (solid, liquid, gaseous, plasma), or can be transferred, but for technical reasons this cannot be transferred efficiently, occurs with a time delay and therefore has to be temporarily stored.

[0003] In addition, certain technical processes are carried out cyclically, whereby the temperature of the process area must be as constant as possible, which must be carried out either as heating, cooling, or both heating and cooling. In such a case, the cyclically generated heat must be removed from the process and fed back into the process flow at the correct timing of the cyclic process. In the latter case, conventional technology primarily uses heat exchanger systems that are coupled with external heat or coolant carriers. In such heat exchanger systems, the heat generated during the process is not recovered or stored, but rather dissipated to the outside or fed into the process from outside. Such processes therefore inevitably require external heat sources and heat sinks.

[0004] According to the state of the art, such heat exchangers are often used in the form of tube bundles and plate arrangements or similar structures, which are characterized primarily by a large internal surface area. The large internal surface area is necessary for optimal and efficient heat transfer and effective thermal coupling of the process area with the environment. For this reason, the higher the efficiency requirements, the larger these heat exchanger systems must be dimensioned.

[0005] Based on their flow-related design, such heat exchanger systems can be divided into various designs. Commonly used are cross-flow heat exchangers, which enable heat recovery of up to 50%, and counterflow heat exchangers, which achieve a heat recovery rate of up to 80%. For the most efficient heat recovery, the highest possible thermal conductivity of the heat exchanger material, the thinnest possible transition layers, the largest possible heat-exchanging surface, and the greatest possible temperature differences between the thermally contacted areas are advantageous. Such heat exchangers also require a sufficiently high degree of thermal insulation to minimize unwanted heat loss.

[0006] Large temperature differences are therefore necessary for rapid heat transfer, as this increases the rate of heat flow through the material. If the temperature differences are too small, the energy recovery rate drops accordingly. The thinner the heat-transfer layer and the larger the surface area for heat transfer in the heat exchanger, the lower the resistance to heat transfer.

[0007] This means that high heat recovery rates can only be achieved by using small plate spacing in the heat exchanger and / or by increasing the system length to increase the surface area within a given installation space. Furthermore, it has been shown that turbulent flow is necessary within conventional heat exchangers. This can result in a very high pressure drop. Otherwise, laminar flow cannot be utilized, because laminar flow creates so-called thermal bypasses due to insufficient heat exchange with the heat-transferring surface.Generating turbulent flow, in turn, requires a disproportionately high energy expenditure to overcome the resulting differential pressure, as well as the use of additional, technically complex and cost-intensive components with corresponding dimensions, such as compressors, fans, pumps, and similar pressure-generating devices. This means that, according to the state of the art, heat exchanger arrangements are unsuitable for cyclic heat recovery in such cyclic processes.

[0008] The energy storage potential of state-of-the-art heat exchangers is very limited. This is due to the fact that heat exchangers must be made of a material with excellent thermal conductivity, which means heat is quickly lost through dissipation. Heat exchangers are therefore practically impossible to use as real heat storage components.

[0009] Added to this is the lack of adaptability. Heat exchangers are designed as a pre-dimensioned component and integrated into a given system. This component cannot be subsequently adapted and is usually difficult to maintain or repair.

[0010] Known prior-art energy storage systems, however, balance the necessary total capacities based on the total amount of energy or heat required or the available space. These are generally not designed for dynamic and cyclical operation, but rather for quasi-static heat storage, which is not suitable for cyclical processes. Document WO 2016 / 150462 A1 discloses an energy storage system with a heat storage material that operates in one operating mode in which the first heat transfer fluid or the second heat transfer fluid flows from one fluid port to another fluid port. A control unit operates the device in another operating mode until the outlet temperature of the first heat transfer fluid, which is discharged from the former fluid port, reaches a predetermined temperature. The temperature sensor for monitoring the energy storage system is located at the fluid port.

[0011] The task therefore arises of implementing an energy storage system that is more efficient and compact than state-of-the-art systems, exhibits lower pressure loss, and also offers greater flexibility and lower losses. The required energy storage method and the corresponding device are intended to implement energy storage that can also be used for the shortest possible process times and cycles and can smooth and uniform the heat flow as effectively as possible, so that the heat generated in the process area or to be supplied to it can be made available accordingly quickly and with a minimum delay in the process cycle.

[0012] The above object is achieved by a method for carrying out cyclic energy storage having the features of claim 1 and a device therefor having the features of claim 15. The subclaims contain expedient and / or advantageous configurations and embodiments of the method and / or device.

[0013] The method according to the invention for carrying out cyclical heat storage or energy storage for a process chamber in cyclical operation is carried out using a storage medium. The storage medium is in contact with a region of higher temperature, hereinafter referred to as the hot side, and with a region of lower temperature, hereinafter referred to as the cold side. Either the hot side or the cold side forms the process area to be temperature-controlled. The method is carried out within a cycle time, with the subsequent method steps being repeated with the following energy storage cycle: In a first step, the energy storage medium is heated on the hot side using a hot medium to initiate internal heat transfer to the energy storage medium from the hot side to the cold side. This creates a heat front that advances from the hot side of the energy storage medium to the cold side.

[0014] In conjunction with this, sensor values are continuously recorded on the cold side of the energy storage medium using a sensor. The continuous temperature is compared with a preset threshold temperature. Ultimately, this monitors the progression of the heat front in the energy storage medium and registers its arrival on the cold side in a timely manner.

[0015] Once the limit temperature is reached, a cooling medium is supplied to the cold side of the energy storage medium, and the stored heat is discharged, starting from the cold side and moving toward the hot side of the energy storage medium. This returns the heat stored in the energy storage medium to the hot side before the cold side of the energy storage medium exceeds the preset limit temperature. This prevents passive energy losses on the cold side, and predefines the energy storage cycle time by specifying the limit temperature.

[0016] The limit temperature can be adjusted to suit the process. If the stored energy is too high, excess energy can be removed from the system. Alternatives include the removal of fluids and media, as mentioned below.

[0017] The above-mentioned process steps are then repeated cyclically. This results in a renewed heating of the energy storage medium on the hot side, thus beginning a new energy storage cycle.

[0018] The basic idea of the method according to the invention is thus a cyclical energy storage system designed from the outset, in which the internal heat conduction in the energy storage material is almost completely eliminated and in which the internal heat conduction, or more precisely, the boundary conditions specified for this in the form of the limit temperature, determines the duration of the energy storage cycle. This creates the possibility of adapting energy storage to a cyclical process designed from the outset, which is particularly carried out dynamically.

[0019] In a practical design of the method, the cyclic operation of the energy storage system comprises two distinct phases: a start-up phase and a working phase. During the start-up phase, several energy storage cycles are run through until the cycle time for each energy storage cycle reaches a constant limit cycle time. This limit cycle time does not change within the next energy storage cycles, provided the externally acting process remains unchanged.

[0020] In the subsequent work phase, the energy storage cycles are then executed within the limit cycle time. The start-up phase thus marks a transient process of cyclic energy storage, which has reached a dynamic equilibrium in the subsequent work phase. In the subsequent work phase, energy quantities can be withdrawn from or added to the energy storage relatively quickly, with the limit temperature being quickly reached or quickly falling below this value again. The energy quantities added to or removed from the energy storage in the energy storage cycles during the work phase then correspond to this temperature change.

[0021] In a further embodiment of the method, the energy storage medium is designed as a material with poor thermal conductivity and permeability.

[0022] The material through which the flow passes is flowed through by the hot medium from the hot side towards the cold side and by the cold medium from the cold side to the hot side.

[0023] In another embodiment of the method, the energy storage medium is distributed between two fluidically separated energy storage modules. Both energy storage modules are connected to a process chamber to be temperature-controlled, and a volume flow flows through the energy storage modules and the process chamber. Both energy storage modules are operated in cyclic push-pull mode. This allows for particularly smooth temperature control of the cyclic process.

[0024] According to the invention, a device for carrying out cyclic energy storage in a process chamber with an energy storage module comprises the following components: An energy storage body made of a material with low thermal conductivity through which a fluid medium can flow is provided. Furthermore, external thermal insulation at least partially surrounding the heat storage body is provided, as well as at least one connection for supplying and / or discharging a fluid. Furthermore, at least one temperature sensor is provided on the energy storage body in the flowing medium and measures the temperature of the fluid.

[0025] In one embodiment, the energy storage body consists of a permeable ceramic with low thermal conductivity. A design consisting of several molded bodies in the form of monoliths, granules, or powder is also possible.

[0026] In a further embodiment, an arrangement of two heat storage modules is provided, which are connected to the process chamber and are directly separated from each other in terms of flow.

[0027] The arrangement of two energy storage modules can be configured in different ways. In a first embodiment, the energy storage modules are connected linearly to the process area on both sides.

[0028] In another embodiment, the energy storage modules are connected to the process area in a U-shape.

[0029] In one exemplary embodiment, the energy storage bodies have a prismatic shape with a freely selectable base area. Cylindrical and cuboidal designs are, of course, also possible.

[0030] The method and the device will be explained in more detail below using exemplary embodiments. The attached figures serve to illustrate this. Figures 1 to 12 The same reference symbols are used for identical and / or equivalent parts.

[0031] It shows: Fig. 1 shows the first method step in an exemplary embodiment, Fig. 2 shows the second method step in an exemplary embodiment, Fig. 3 shows the third method step in an exemplary embodiment, Fig. 4 shows the renewed first method step following the third method step in an exemplary embodiment, Fig. 5 shows an illustration of the cycle time as a function of the number of cycles, Fig. 6 shows a schematic illustration of the temperature profile on the cold side of the energy storage body as a function of the number of cycles, Fig. 7 shows exemplary cross-sectional shapes of an energy storage body, Fig. 8 shows an exemplary structure of an energy storage module, Fig. 9 shows an exemplary linear vertical structure of two energy storage modules with a process area located between them, Fig. 10 shows an exemplary linear horizontal structure of two energy storage modules with a process area located between them, Fig.11 an exemplary construction at a corner consisting of two energy storage modules with an adjoining process area, Fig. 12 another exemplary construction at a corner consisting of two energy storage modules with an adjoining process area, .

[0032] The following basic configuration applies to all of the exemplary embodiments explained here: The term "energy storage device" is understood below to mean a space filled with a material through which a fluid can flow. The material used for energy storage is ideally a material with low thermal conductivity (i.e., a thermal insulator), while the material also has a high specific heat capacity. The material in the energy storage device can be a fluid, in particular a liquid, but also a solid such as granules or a powder, or even a porous solid through which fluid can flow.

[0033] The Figures 1 to 4show the basic process steps of the cyclic energy storage according to the invention. For this purpose, an energy storage medium W is provided. The energy storage medium W can in particular be a ceramic with low thermal conductivity through which a fluid can flow. The energy storage medium is located between two regions with different temperatures. The region with the higher temperature forms the hot side H of the energy storage medium W, and the region with the lower temperature forms the cold side K of the energy storage medium. The hot side H or the cold side K is assigned to a process chamber that is to be temperature-controlled and from which energy is to be cyclically withdrawn and into which energy is to be cyclically fed back.If the process space is assigned to the hot side, the process is kept at a higher temperature, i.e. ultimately heated; if the process is assigned to the cold side, the process is kept at a lower temperature, i.e. ultimately cooled.

[0034] The terms "hot side" and "cold side" do not indicate the magnitude of the temperature difference between the designated areas; they only indicate which side has a higher and which a lower temperature. Likewise, the following terms "hot medium" and "cold medium" are used only to indicate the fact that the respective fluids have different temperatures.

[0035] In the example from Fig. 1 to Fig. 4The hot side H is assigned to the process to be tempered. The energy storage medium W is provided with thermal insulation I on the outside. However, there is a thermal connection between the hot side H and the cold side K, and it is also possible for fluids to flow through the energy storage medium.

[0036] A sensor S is arranged on the cold side K of the energy storage medium. The sensor measures a measured variable that provides information about the energy content of the energy storage medium. The sensor S is designed as a temperature sensor that measures the temperature of the energy storage medium in the cold side region and outputs it to an external control unit (not shown here). The external control unit regulates the fluid flow to and through the energy storage medium W during the energy storage cycle described below. This is achieved in particular by switching pump devices (not shown here) and by setting valve positions.

[0037] In the Fig. 1In the first process step shown, warm fluid flows from the hot side H as a hot medium HM through the energy storage medium in the direction of the cold side. The fluid gradually transfers a certain amount of energy Q to the energy storage medium W and heats it up in the process. This heating starts on the hot side H and gradually progresses towards the cold side K in the form of a heat front WF. A temperature gradient develops in the energy storage medium between the hot side H and the cold side K. The hot side has a high temperature T high and the cold side has a low temperature T low.

[0038] As time progresses, the heat front WF advances through the entire energy storage medium W and finally reaches the cold side K.

[0039] The arrival of the heat front WF is finally registered on the cold side K by the sensor S located there. In this example, the metrological criterion for the arrival of the heat front WF is the reaching of a certain predefined limit temperature T limit on the cold side K of the energy storage medium. The temperature gradient now prevailing in the energy storage medium is established between the high temperature T high on the hot side H and the limit temperature T limit on the cold side K.

[0040] As soon as the limit temperature T limit has been reached, the external control unit stops the fluid flow from the hot side H to the cold side K before energy from the energy storage medium W can pass directly into the environment of the cold side K. This is done by setting appropriate valves and / or pumping devices.

[0041] According to Fig. 3The flow of the fluid is reversed by the control unit and by switching the external valves and / or pumping devices. This switching takes a certain amount of time, during which the fluid is practically motionless, and which therefore represents a dead time t tot for the process.

[0042] The fluid is now conducted as a cold medium KM from the cold side K through the energy storage medium W to the hot side H. As a result, the temperature of the energy storage medium, which is registered by the sensor S, drops below the limit temperature T limit . The heat front WF is now pushed back from the cold side K to the hot side H of the energy storage medium W. In the process, the energy Q stored in the energy storage medium W is returned to the hot side H.

[0043] The basic criterion for the duration of this return and for the time of the subsequent switching is that the switching takes place when a predetermined temperature of the hot medium is undershot.

[0044] In a combined system of two heat storage units operating in push-pull mode, this point in time is defined as the moment at which the temperature increase on the cold side of the second heat storage unit occurs.

[0045] The energy storage medium thus works as a cyclic energy buffer that absorbs the energy from the hot side H, stores it temporarily and finally returns it to the hot side.

[0046] The above-mentioned process steps can now be repeated, completing the cycle and beginning again. The time from the start of the cycle until the completion of the energy Q being driven back to the hot side is referred to below as the cycle time t cycle.

[0047] Due to the cyclical and thus essentially periodic nature of the operation described here, other definitions of cycle time are also possible. Cycle time can also be defined as the time from the temperature increase on the cold side on one side to the increase on the other side.

[0048] The cycle time t cycle has a characteristic dependence on the number of cycles completed, ie the cycle number n. In Fig. 5This dependency is shown schematically. At the beginning of the cyclic operation of the energy storage, the cycle time is initially high and then decreases with increasing number of cycles. It finally adjusts to a limit cycle time t limit, which essentially remains constant for all subsequent cycles. The range of the first cycle numbers, in which the cycle time decreases from an initial maximum value, forms the start-up phase An of the cyclic energy storage method. The range of the subsequent cycles, in which the limit cycle time has been reached and, with otherwise constant conditions, essentially only fluctuates around a constant value, forms the actual working phase Ar of the cyclic energy storage method according to the invention.

[0049] Fig. 6shows the temperature fluctuations measured in the present example at the sensor of the energy storage medium, i.e. here at the temperature sensor, as a function of the number of cycles. As described, the method is designed such that the limit temperature T limit is predetermined in a control unit and is not exceeded during the method. The temperature applied and measured at the sensor can therefore only be less than or equal to the limit temperature T limit. Below the limit temperature T limit, the measured temperature oscillates over the course of the cycles within a certain fluctuation range, which is designated by Δ in the present diagram. The fluctuation range Δ is comparatively large at the start of the cyclic energy storage, i.e. during the start-up phase An, but decreases and approaches a constant fluctuation limit value Δ limit which, however, is different from zero as the number of cycles increases.Setting the fluctuation range Δ to the achieved constant fluctuation limit Δ Limit then marks the transition from the start-up phase to the operating phase of the cyclic energy storage process. The fluctuation limit Δ Limit then marks the amount of energy that can ultimately be stored and transferred back to the cyclic process by the cyclic energy storage process.

[0050] As described, the process steps are thus divided into thermal charging, subsequent switching, and subsequent thermal discharging. The term "thermal charging" here refers to the introduction of energy into the energy storage medium, while the term "thermal discharging" expresses the withdrawal of energy from the energy storage medium.

[0051] It is advantageous to use an energy storage device with the poorest possible heat conduction. Good heat conduction in the energy storage device has a significantly negative impact on the overall efficiency of energy recovery. In a poor heat conductor, i.e. a thermal insulator, the heat front moves forward very slowly during energy storage. The heat front therefore has a steep incline. The movement of the heat front depends on the flow velocity. As a result, the fluid flowing through the storage device slowly but essentially completely fills it with the introduced energy until breakthrough occurs, i.e. the introduced energy is dissipated into the external environment. This also keeps the temperature difference for heat transfer large, so that the energy flow is faster and easier when passing quickly through the module.

[0052] It should be noted at this point that the objective is not simply to cool or heat the fluid flowing through the energy storage medium, i.e., to bring it to a high or low temperature as quickly as possible. Rather, the objective is to supply energy to the energy storage medium or extract energy from it in a manner that is as easily controllable as possible.

[0053] In contrast, with a material that conducts heat well, the energy is dissipated early. This happens even when only a portion of the fluid's cycle volume has flowed through the energy storage device. This is precisely the effect that the method according to the invention is expressly intended to avoid.

[0054] Two important aspects are important here. First, the residence time or flow velocity of the fluid flowing through the energy storage system must be adjusted so that the energy can be transferred from the flowing fluid to the energy storage medium in such a way that the energy storage medium is as saturated as possible. If the fluid's residence time is too short, the energy is not fully transferred to the energy storage medium. The second aspect concerns the full utilization of the heat capacity of the energy storage device. When using a hollow ceramic, for example, this dictates a certain wall thickness, which must be utilized as fully as possible during heat conduction from the outside to the inside for energy storage.

[0055] The time required for heat conduction must also be taken into account. With optimal adjustment of the residence time, ideally almost the entire storage volume of the energy storage medium reaches the maximum specified process temperature, i.e., essentially the limit temperature T limit, before the stored energy is released again.

[0056] The exclusive use of highly dynamic valves or flaps for fluidic control of the fluid flow through the energy storage modules filled with the energy storage medium is advantageous. This enables correspondingly short switching times and thus minimizes downtime.

[0057] The system can also be used to keep the process area cool and to position it between two energy storage media. In this case, the hot and warm zones of the energy storage media are located on the outside of the process space. One application for this is, for example, ventilating living spaces in the summer without overheating the living area. This can save energy on the air conditioning system that would otherwise be required. In this configuration, a temperature sensor at the end and beginning of each energy storage unit is very useful.

[0058] The energy storage system is thus operated as an active system with sensors for measuring parameters of the fluid flowing through the energy storage medium and the temperature of the energy storage medium. The sensors prevent energy discharge or energy losses from an internal energy recovery system.

[0059] During the start-up phase of the energy storage process, it is possible to perform only a partial energy charge of the storage units to make the energy storage units operational more quickly. This can accelerate the attainment of the limit cycle time t limit.

[0060] Below, some aspects of the process, particularly those related to timing, will be explained in more detail. In the following explanations, V cycle denotes the cycle volume, V dead volume, M cycle the cycle mass, M dead mass, t cycle the cycle time, and t dead the switching time. The following discussion assumes that the energy storage system is in the operating phase and that the cycle time t cycle corresponds to the limit cycle time t limit. Therefore, t cycle = t limit .

[0061] The switching time t tot refers to the time required to switch the flow direction of the fluid flowing through the energy storage medium. During this time, neither energy is transferred to the energy storage medium nor is energy recovered from the energy storage medium. In fact, no fluid is moved through the energy storage device during the switching process. The switching time t tot therefore represents a true dead time for the entire cyclic process.

[0062] The cycle volume V cycle is the volume of fluid that can be actively driven through the energy storage medium during a cycle. The dead volume V tot refers to the volume of fluid that is necessarily at rest and thus not moving in the energy storage medium and in the corresponding feeds during the switching time. The cycle mass M cycle is the total amount of fluid moved during the cycle. The dead mass M tot is the amount of fluid that is necessarily not moving, i.e., stagnant, during the switching time t tot.

[0063] In principle, it is advantageous that the switching time t tot should be small compared to the cycle time t cycle. Under this condition, the cycle volume V cycle is large compared to the dead volume V tot and the following applies: V Zyklus > > V tot .

[0064] Likewise, the cycle mass M cycle is large compared to the dead mass M dead. M Zyklus > > M tot

[0065] The respective masses can be determined from the volumes, taking into account the corresponding relationships in gaseous or liquid, i.e. compressible and incompressible media.

[0066] During the switching time, essentially only valves are operated or, at most, the flow directions of pumps are changed. It is advantageous that the cycle time t cycle should be large compared to the switching time t tot : t Zyklus > > t tot .

[0067] The switching is thus carried out in the shortest possible time. If the process area to be tempered is located between two energy storage modules and the process area is thus first flowed in one direction and then in the opposite direction, the very rapid switching between the at least two energy storage units within a module generates a nearly permanent flow of the fluid with an energy transfer of more than 90%, which can also be increased to over 99%.

[0068] Technically speaking, the efficiency of this process can be increased variably based on the design by making the heat exchanger very long and keeping the switching times extremely short. This is only economically viable up to a certain application-specific point.

[0069] The total volume or the total mass of the available fluid is thus reduced by the dead volumes V tot or the dead masses M tot , respectively, depending on the partial times of energy storage, i.e. the cycle time t cycle and the dead or switching time t tot . These are calculated from the following relationships: The required total time t ges of energy storage is the sum of the cycle time t cycle and the switching time t tot : t ges = t Zyklus + t tot s

[0070] The volume converted during the total time is calculated from the partial volumes converted or present during the times t cycle and t tot: V total = V cycle (t cycle ) + V tot (t tot ) [m 3< ]. A corresponding relationship also applies here for the respective partial masses.

[0071] The proportion of cycle time to the total time At cycle is calculated from the ratio between the cycle time and the total time: At Zyklus = t Zyklus / t ges , The proportion of the switching time to the total time At tot is given by: At tot = t tot / t ges .

[0072] The number of cycles per hour is defined by a factor F with factor F = 3600s / t total. From this, the total volume flow V total per hour can be calculated as follows: V gesh = V ges * F m 3 / h .

[0073] This total volume flow V gesh per hour also results from the sum of the switching volume V s and the useful volume V n : V gesh = V n + V s m 3 / h .

[0074] Using the factor F, the switching volume V s and the useful volume V n per hour can be calculated. The switching volume V s is determined from the dead volume V tot using the factor F: V s = V tot * F [m 3 / h].

[0075] The useful volume per hour V n is the sum of the cycle volume flow V cycle per hour [m3 / h] and is determined using the factor F to V n = V Zyklus * F m 3 / h .

[0076] The masses can also be calculated accordingly here.

[0077] To ensure the greatest possible compactness of the energy storage system, the energy storage system can be designed modularly.

[0078] Fig. 7 shows exemplary cross-sectional shapes of an energy storage module. As the examples shown here demonstrate, the cross-sectional shape is not limited to a specific form. It can be rectangular, in particular square, circular to oval, or polygonal, in particular hexagonal or even octagonal. The appropriate choice of the specific cross-section results in the individual case from a consideration of the manufacturing effort on the one hand, and on the other hand from the appropriate selection of the ratio between volume and surface area in order to, on the one hand, provide a large volume for energy storage and, on the other hand, to minimize the surface area and thus the energy losses to the environment.

[0079] Fig. 8shows the basic structure of an exemplary energy storage module 8. The individual energy storage module consists of a filling 5 made of an energy storage material. This filling forms the energy storage body 8a. The energy storage body is surrounded on the outside by thermal insulation 8b. The energy storage material serves as the energy storage mass. This energy storage material can expediently be flowed through by a fluid and can be designed, for example, as a loose ceramic filling or a porous ceramic body. The energy storage material is surrounded by a module housing 6. The fluid is supplied and removed within the module housing. The temperature of the fluid at the outlet and inlet of the energy storage module as well as the temperature of the energy storage module in the filling 5 are continuously monitored via temperature sensors 7.

[0080] Fig. 9shows a coupling of energy storage modules 8 in a vertical configuration. This configuration also includes a filling 5, a module housing 6, and a temperature sensor 7. Each of the energy storage modules contains an energy storage body 8a, which is formed in particular by the filling with the energy storage material, and an external thermal insulation 8b, which is in particular a part of the module housing. Between the coupled energy storage modules is the process area 9, which represents a flow direction reversal area into and out of which the fluid F can be introduced into and discharged from the energy storage modules. This flow direction reversal area contains the process to be temperature-controlled and thus marks the process area 9 to be temperature-controlled.

[0081] Both energy storage modules work in push-pull mode to control the temperature of the process area 9 in the flow reversal area. The process area 9 forms a flow reversal area through which flow can occur from two sides in opposite directions depending on the working cycle. In principle, this occurs by transferring fluid from a hot, i.e. energy-laden, energy storage module through the flow reversal area 9 into the cold energy storage module, thus resulting in an internal energy transfer between the two coupled modules and preventing the stored energy from escaping from the hot energy storage module into the environment. The redistribution of the fluid between the energy storage modules creates a predetermined direction in which stored energy can preferably flow away in a predetermined manner.

[0082] The coupling between the energy storage modules and the flow reversal area can be designed in a very variable manner, both geometrically and in terms of position. Fig. 10 For example, the coupling is designed in a horizontal configuration.

[0083] Both in the example from Fig. 9 as well as in the example from Fig. 10 The energy storage modules 8 are arranged linearly one behind the other. This configuration also represents only one possible embodiment. The examples from the Figures 11 and 12 show angled arrangements between the energy storage modules, in which the fluid is guided at least at an angle between the two energy storage modules. The two energy storage modules are otherwise separated from each other, so that no direct fluid or energy transfer can take place between the individual modules.

[0084] A device for temperature control of a process area is therefore expediently based on an arrangement of at least two energy storage devices, in particular at least two energy storage modules, which are alternately charged and discharged with energy from the fluid flowing past the process to be temperature-controlled and through the module. The energy to be stored and the available total energy capacity are thereby broken down into small portions and frequently switched back and forth via the flowing fluid. The more frequently the storage devices are charged and discharged, the smaller the capacity of the individual energy storage module must be. This procedure reduces energy slip to a minimum.

[0085] The configuration with at least two energy storage modules can take various forms. Several energy storage modules can be arranged as shown in Fig. 9 and 10in particular, just or according to the representations in the Figures 11 and 12 connect to the flow reversal area 9 at one or more angles or via curves.

[0086] When building from Fig. 9 The flow reversal region 9 is arranged between two energy storage modules 8. This entire linear arrangement is traversed by a continuous fluid stream F in alternating directions. In step with the overall process, the flow direction changes within the overall system, particularly in the flow reversal region 9, which contains the process to be tempered. Several temperature sensors 7 are provided on the energy storage modules 8 and record the temperatures present in the energy storage modules.

[0087] This linear arrangement according to Fig. 9can be configured both vertically and horizontally. The flow reversal area containing the process to be tempered is enclosed by the energy storage modules either laterally or between its top and bottom.

[0088] In terms of design, a linear design with the process area between the at least two energy storage units is advantageous due to its ease of manufacture, while a vertical design with two or more energy storage units arranged parallel to one another and the process area at the transition between the at least two energy storage units at the upper end is advantageous for improved energy recovery through the use of convection. Combinations and modifications of these are also possible.

[0089] In the embodiment from Fig. 11 and the embodiment from Fig. 12The flowing fluid F is directed in alternating directions around the corner. The energy storage modules 8 are connected to the flow reversal area 9 in a common side area.

[0090] Possible fluids F include gases, particularly He, N, H 2 , CO 2 , CO, O 2 , other gases or mixtures, e.g., natural gas or air, plasma, or steam. Liquids, ionic liquids, or melts can also be used. Fluid-like solids, particularly in the form of a bed, such as sands or combinations of gases, liquids, plasmas, and fluid-like solids, can also be used. The latter can be, for example, sands, powders, or granules, which are particularly free-flowing.

[0091] The cycle time t cycle of the configurations given here is usually in the range of minutes, for example, a maximum of 10 minutes and a minimum of 20 seconds. The switching time t tot is usually in the range of seconds, for example, a maximum of 3 seconds and a minimum of 1 millisecond.

[0092] The ratio of the cycle time t cycle to the switching time t dead , i.e., the quotient t cycle / t dead , must be as large as possible to minimize dead volume and generate a nearly continuous flow. The ratio should ideally be at least 100. A ratio of 500 or greater than 1,000 is advantageous. The larger the factor, the higher the theoretically possible energy recovery.

[0093] The ratio of the cycle volume V cycle (e.g. 100 m 3 / h) to the dead volume V dead (e.g. 0.45 m 3 / h) of the fluid, i.e. the quotient V cycle / V dead, should not fall below a value of 100 within the given cycle time. A ratio of the cycle volume to the dead volume in the range of 200 or even more than 300 is advantageous.

[0094] The cold fluid is conveniently fed into the system via a temperature-controlled system. This ensures a controlled temperature in the storage tanks and protects against overheating. Temperature control is possible at any point upstream of the storage tanks.

[0095] Within the framework of the process, it is in principle possible to remove warm fluid from the energy storage process at any time. The warm fluid can then be used to utilize the energy in other processes, and its removal enables overheating protection for both the energy storage system and the temperature-controlled process. Such removal of the warm fluid is possible at virtually any time before and after storage, as well as from the energy process area.

[0096] The process of feeding and discharging the fluid can take place in parallel.

[0097] Several modules can be connected in parallel to increase the throughput, the volume flow or to reduce the pressure or pressure loss across the system.

[0098] It is possible to introduce additional material into the process chamber as a storage increase or functional unit. Several modules can be connected in series to combine multiple analysis systems at different temperatures, multiple sequential material separation or conversion processes with different input parameters, or multiple, both different and identical, repeating reaction steps, for example, to increase yields.

[0099] The energy storage method and the device-side configurations illustrated here have the advantage that the temperature at the outlet of the energy storage system is only slightly above the inlet temperature. This reduces the thermal load on alternative sensors and allows the use of sensors that could not previously be used. For example, this allows the process temperature to be controlled based on the reaction products.

[0100] The energy storage process and the device-side configurations illustrated here have the advantage that the process sequence can be stopped with virtually no sluggish run-on. This allows for relatively quick restart of the system, provided the downtime is not extended too long and sufficient stored energy remains in the system. Simple adjustments to the system are also easily possible retrospectively, namely by adapting the energy storage material, the sensors, the control parameters, and by adjusting the energy storage geometry, the energy storage mass, and the energy storage surface.

[0101] The energy storage unit is designed to be dismantled and therefore easy to repair. A modular design is advantageous here, as the filling in the module housing can be removed and replaced as a component. This allows the entire assembly to be easily replaced, repaired, and maintained, either partially or completely. Energy can be stored both positively in the form of heat and negatively in the form of cold, depending on the heating or cooling processes.

[0102] Energy recovery is possible even at very small temperature differences of less than 10K, especially less than 5K and even at a temperature difference of less than 1K.

[0103] The heat exchanger within the internal energy recovery system can be operated with a variable flow rate between zero and a maximum value. At a flow rate close to zero, heat transfer is almost complete. The cycle time assumes very large values, while the switching time component becomes comparatively small.

[0104] The maximum flow rate, however, depends on the flow velocity, the internal surface of the energy storage device, the temperature difference, and other variables. Above the maximum value, the heat can no longer be fully transferred to the energy storage device and essentially flows past the energy storage device with the fluid. In this case, the switching time would become too large, and efficiency would collapse. The maximum flow rate is therefore a system-specific variable.

[0105] A very compact design of the individual energy storage modules is possible because the insulation can be eliminated or at least greatly reduced due to the short switching times and the associated significant reduction in energy conduction between the energy storage units.

[0106] Due to the very high energy recovery, electricity can now be used as a heating medium in addition to natural gas. This is also possible for large fluid flows. Ideally, electricity from renewable sources would be used for this purpose to achieve sustainable CO2 reduction. The use of hydrogen as a heating medium would also be possible to increase sustainability.

[0107] The energy storage and feedback process can be used in various systems and in various fields of application: A first area of application is analysis systems: This particularly concerns procedures and processes in which a sensor with a fluid flowing around or through it must be kept at a certain temperature or within a certain temperature range.

[0108] Another area of application concerns thermal systems, in particular thermal processes for energy transfer (heating, cooling), for material separation and / or material conversion, e.g. extraction, rectification, adsorption, desorption, drying, catalysis, in which certain temperature ranges must be maintained and the resulting energy quantities must be transferred back into a specific system or system sections.

[0109] Furthermore, the energy storage method according to the invention can be applied to reaction systems, in particular to oxidation, reduction and synthesis processes in which a medium must be heated to a certain temperature.

[0110] The energy storage method according to the invention can also be applied to fluid exchange systems, in particular in conjunction with a sensor system for monitoring, controlling and adjusting values or ranges for compositions of fluids, such as hydrogen, nitrogen, carbon monoxide, carbon dioxide, oxygen, in which the relative humidity, temperature, organic pollutants or other gases, liquids and particles or fluids according to definition and mixtures thereof must be controlled.

[0111] Another area of application is furnaces with gas burners, where a supply of preheated oxygen is required. Here, the system according to the invention can increase the furnace temperature and thus the furnace's efficiency.

[0112] Another field of application is the condensation of liquids below the dew point or through the use of adsorbents.

[0113] In one embodiment, the method can be linked to a process in such a way that the air flow creates a recirculation system that is tempered by the method, for example for a sintering furnace.

[0114] The applications can also be used in combined processes in which several of the above-mentioned application areas are coupled.

[0115] Finally, the advantageous effects achieved by the energy storage device according to the invention should be briefly summarized: The energy recovery rate can be up to 99.99%. It is independent of the temperature difference. The energy recovery rate is controllable. The pressure drop across the energy storage modules can be varied and is significantly lower compared to standard heat exchangers. The volume flow of the fluid can be freely selected, depending on the fan power or the power of the pump that drives the flowing fluid. The energy storage device is operated via an active control system. The entire arrangement is flexible thanks to its modular design. A weight saving of 50% can be achieved compared to counterflow plate heat exchangers.

[0116] The energy storage device according to the invention has a compact and variable shape. The pressure loss is individually adjustable. Excess energy can be directly utilized. The use of ceramic as the energy-storing material results in temperature stability of up to 1,200°C. High chemical resistance is present, particularly when ceramic materials are used for energy storage. Ceramic has a lower coefficient of thermal expansion than metals, such as steel and stainless steel, making it more stable over the long term than standard heat exchangers. The achievable compactness of the systems also minimizes absolute thermal expansion while maintaining a constant volume flow.

[0117] The achievable service life can exceed 10 years. The modular design of the energy storage system allows for a simple, dismantled structure with inexpensive spare parts and high availability.

[0118] The method and device according to the invention have been explained using examples. Further embodiments are possible within the scope of one skilled in the art. Further embodiments are also apparent from the dependent claims. List of reference symbols

[0119] AnStart-up phase ArWorking phase FFluid HHot side HMHot medium IThermal insulation KKold side KMcold medium QAmount of energy TTemperature sensor SSensor WEnergy storage medium WFHeat front 1square 2circular 3hexagonal 4octagonal 5Filling with energy storage material 6Module housing 7Temperature sensor 8Energy storage module 8a 8bEnergy storage body thermal insulation 9Flow reversal area

Claims

1. A method for carrying out a cyclic energy storage for a process space (P) in a cyclic operation using an energy storage medium (W) with a hot side (H) and a cold side (K) with the following method steps repeated within a cycle time (tZyklus) with the following energy storage cycle: - heating up the energy storage medium (W) on the hot side (H) by means of a hot medium (HM) for initiating an energy transfer to the energy storage medium (W) from the hot side (H) to the cold side (K), - continuously registering the sensor values on the cold side (K) of the energy storage medium (W) by means of a sensor (S) arranged on the cold side of the energy storage medium (W) and measuring the temperature of the energy storage medium (W) in the region of the cold side (K) and comparison with a preset threshold (SGrenz) (Figs. 2 and 6), - wherein a heat front (WF) progressing through the energy storage medium (W) and arriving on the cold side (K) is registered by the sensor (S), - after reaching the threshold (SGrenz), feeding a cold medium (KM) to the cold side (K) of the energy storage medium (W) and discharging the stored energy starting from the cold side (K) in the direction of the hot side (H) of the energy storage medium (W), - wherein the heat front (WF) is forced back from the cold side (K) to the hot side (H) of the energy storage medium (W), - renewed heating up of the energy storage medium (W) on the hot side (H) and start of a renewed energy storage cycle.

2. The method according to claim 1, characterized in that the cyclic operation has a start-up phase (An) and a working phase (Ar), wherein in the start-up phase a plurality of energy storage cycles are run through until the cycle time (tZyklus) has reached a constant limit cycle time (tGrenz) for each energy storage cycle, and wherein in the working phase the energy storage cycles are each carried out within the limit cycle time (tGrenz).

3. The method according to claim 1 or 2, characterized in that the energy storage medium (W) is formed as a thermally poorly conductive material, wherein the thermally poorly conductive material is flowed through from the hot side (H) in the direction of the cold side (K) by the hot medium (HM) and from the cold side (K) to the hot side (H) by the cold medium (KM).

4. The method according to one of the preceding claims, characterized in that the energy storage medium (W) is distributed over two energy storage modules separated from one another in terms of flow, wherein both energy storage modules adjoin a process space to be temperature-controlled and the energy storage modules and the process space are flowed through by a continuous volume flow, wherein both energy storage modules are operated in a cyclic push-pull mode.

5. The method according to claim 4, characterized in that the energy storage modules can be connected in parallel or in series in any desired manner depending on the requirement.

6. The method according to one of the preceding claims, characterized in that the cycle time (tZyklus) is set as the time period from the increase in the temperature on the cold side on the one hand to the increase on the other hand such that it is small compared with the time period of a heat conduction running within the energy storage medium (W).

7. The method according to one of the preceding claims, characterized in that the ratio of the cycle volume VZyklus and the dead volume Vtot of the fluid does not fall below a value of 100 within a given cycle time and advantageously has a value in the range of 200, preferably more than 300.

8. The method according to one of the preceding claims, characterized in that the switch-over time (ttot) is chosen to be much smaller in comparison with the cycle time (tZyklus).

9. The method according to one of the preceding claims, characterized in that an additional medium is supplied in the process space.

10. The method according to one of the preceding claims, characterized in that a medium is discharged in the process space.

11. The method according to claim 9 and 10, characterized in that the medium is fed in and discharged in a temporally parallel manner.

12. The method according to one of the preceding claims, characterized in that the process space is partially to completely filled by one or more through-flowable media.

13. The method according to one of the preceding claims, characterized in that the method is used for operating a cooling reservoir.

14. A device for carrying out a cyclic energy storage at a process space (P) with an energy storage module (8) with the following components: an energy storage body (8a) made of a material through which a fluid medium can flow in the form of a filling (5) with a low thermal conductivity, an outer thermal insulation (8b) at least partially surrounding the energy storage body (8a), at least one connection each for supplying and / or discharging a fluid (F) and at least one sensor (S) arranged on the energy storage body (8a) in the form of a temperature detector (7) continuously monitoring the temperature of the energy storage module (8) in the filling and a control unit regulating the fluid flow to and through the energy storage medium (W), in particular setting pumping devices and valve positions.

15. The device according to claim 14, characterized in that the energy storage body (8a) consists of a ceramics, a composite material or a liquid with low thermal conductivity.

16. The device according to claim 14, characterized in that the energy storage body (8a) consists of one or more moulded bodies, e.g. monoliths, granules or powders.

17. The device according to claim 14, 15 or 16, characterized by an arrangement of two energy storage modules (8) adjoining the processing region and directly separated from one another in terms of flow.

18. The device according to one of claims 14 to 17, characterized in that the energy storage modules (8) are linearly connected to the processing region (9) on both sides.

19. The device according to one of claims 14 to 18, characterized in that the energy storage modules are connected to the processing region in a U-shaped manner.

20. The device according to one of claims 14 to 19, characterized in that the energy storage bodies (8a) have a prismatic shape with an arbitrarily selectable base area.