Fluidized bed heat exchanger and method

Abstract

To provide an apparatus (100) for thermal energy storage and conduction.SOLUTION: The apparatus (100) includes a thermal energy input device (1) having a bed of fluidizable solid particles received in a casing and exposed to a thermal energy source to function as a heat storage means, a heat exchange means (3) operating in counter-current flow and configured for exchange of thermal energy between a heated vector mass of the bed particles and a working fluid, a transport means (5) configured for supplying the vector mass of the bed particles from the device (1) to the heat exchange means (3) and for returning at least part of the vector mass to the device (1) downstream of the heat exchange means (3), and a control unit (10) associated with a parameter detection means (6).SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] overview Technical field of the invention The present invention relates generally to devices, systems and methods for the storage and transfer of thermal energy.

[0002] In particular, the present invention uses a device for the storage of thermal energy based on a bed of fluidizable solid particles. [Background technology]

[0003] background Devices for the storage and conduction of thermal energy based on fluidized or fluidizable beds of solid particles are known in the art.

[0004] In the above systems, the heat exchanger is immersed in a bed of particles. Such an exchanger may, for example, rely on a bundle of tubes traversed by a working fluid, such as steam or CO2.

[0005] In its simplest configuration, the particle bed can be assumed to be isothermal, i.e., each and every particle mass has the same temperature. This approximation is acceptable due to the high thermal diffusivity throughout the fluidized bed. Under these conditions, thermal energy is stored in the bed in the form of sensible heat of the solid particles, given by Q=m*c p *ΔT[1], where Q is the thermal energy stored in the fluid layer, m is the total mass of the bed particles, c p is the specific heat capacity of the particle, ΔT is the solid particle temperature (T max -T min ) and T min and T max are the minimum and maximum operating temperatures of the bed particles during heat exchange, respectively.

[0006] As given above, once thermal energy is stored in the bed, i.e., heated, such energy can be released to a heat transfer fluid (HTF), such as steam, CO2, supercritical CO2, etc., by means of said heat exchanger immersed in the bed.

[0007] The temperature produced in the HTF is of course always below the bed temperature and can be adjusted (for example by a so-called steam desuperheater) to meet the requirements for use.

[0008] For better understanding, the diagrams in Figs. min is 350℃, T max 6 shows the possible temperature trends of the bed mass (made of, for example, sand particles) and of the heat transfer fluid (for example, steam) when the temperature is assumed to be 620° C. and the steam generation time is 6 hours.

[0009] In particular, Figure 1 shows a steam temperature that constantly decreases with decreasing solid particle temperature, Figure 2 shows a steam generation profile that is 500°C for the first 2 hours and then decreases with decreasing solid particle temperature, while Figure 3 shows a constant steam generation at 300°C over the entire period.

[0010] The figure shows that in all cases, the HTF is the minimum fluid layer temperature (T in the example shown) for at least some time. min This indicates that the material is formed at temperatures below 350°C. It is important to keep in mind that:

[0011] In other words, for applications where HTF is always required at, say, 500°C, the solution presented above cannot work unless the particle minimum temperature is increased above 500°C (eg, 530°C).

[0012] However, T minThis increase in temperature has a significant negative impact on the heat storage capacity, as the solid particle operating temperature ΔT is significantly reduced. To stay with the example above, ΔT must be reduced from (620-350)°C = 270°C to (620-530)°C = 90°C, which means that the heat storage capacity is reduced by a factor of three if steam has to be produced at 500°C instead of 300°C.

[0013] Theoretically, this gap is the maximum temperature of the fluid layer (T max ), but this increase may not be feasible (and / or economical), particularly due to operational limitations of the heat exchanger materials. Referring again to the example above, a minimum fluid layer temperature (T min ), to consistently produce steam at 500°C by maintaining the same thermal energy storage capacity, the maximum fluid bed temperature would have to increase from 620°C to 800°C (i.e., 530+ΔT=530+270=800°C), which may be infeasible due to limitations in heat exchanger materials.

[0014] Another possible solution to maintain the same heat capacity when producing steam at higher temperatures (e.g., 500°C) is to increase the solid particle mass, but again this involves a significant increase in cost and a much larger module (in the example, three times larger).

[0015] The above considerations are even more important when the HTF is supercritical CO2, which today is expected to be capable of driving turbines with estimated thermal-to-electrical efficiencies of up to 50%, although the supercritical CO2 is delivered to the turbine at temperatures in excess of 700°C (and pressures in excess of 200 bar).

[0016] In these cases, the fluid layer must function in a very high temperature range (e.g., 730°C to 1000°C), which, even if possible for solid particles, may make the construction of immersed heat exchangers impractical or may shorten their lifespan too much due to the aforementioned material limitations. Summary of the Invention [Problem to be solved by the invention]

[0017] Therefore, there is a need for fluid particle layer based devices, systems and methods that better enable the storage and exchange of thermal energy in an efficient manner, especially in certain applications. [Means for solving the problem]

[0018] Summary of the Invention The technical problem posed and solved by the present invention is therefore to provide a heat storage and conduction arrangement based on a fluid layer of solid particles that makes it possible to overcome one or more of the drawbacks or criticisms mentioned above with reference to the known art.

[0019] It is an object of the present invention to provide a device, apparatus, system and / or method for storing and transferring energy in the form of heat that is particularly effective in ensuring the continuous production of high temperature heat transfer fluid for supplying electrical or thermal energy to an end user.

[0020] According to another aspect, the present invention provides a method for treating a dipped particle layer in the same particle layer that is exposed to a thermal energy source. The present invention aims to overcome some of the performance limitations inherently associated with the heat transfer mechanism of thermal energy storage achieved by fluidized beds of solid particles with integrated heat exchangers.

[0021] The above object is achieved by an apparatus according to claim 1 and by a method according to claim 13.

[0022] Preferred features of the invention are set out in the dependent claims.

[0023] The present invention is based on a device that allows the storage of energy in the form of heat in a bed of fluidized solid particles and the simultaneous or delayed transfer of the stored energy to a working fluid.

[0024] The inventive arrangement allows for an efficient and flexible use of the energy leaving based on the needs of the end user. Advantageously, the stored energy can be converted into electrical energy, used directly in the form of heat, or even used in a combined manner in industrial applications (CHP, Combined Heat and Power Plant).

[0025] The present invention is applicable to so-called "concentrated solar power" configurations, where the thermal power is injected into the storage layer by solar radiation, i.e. by solar radiation impinging on the storage layer, either directly or indirectly, after one or more reflections or re-irradiations, with or without means such as transparent screens inserted between the layer and the solar source / radiation.

[0026] Compared with other concentrated solar power solutions based on solid particles, solar receiver / thermal storage devices based on fluid layer technology have better performance, providing a buffer time for heating the particles and ensuring solid particle temperature control for higher performance and safety of operation. This feature is particularly important during rapid transient changes in solar energy input to the receiver device, such as the sudden appearance / disappearance of clouds, or to accommodate varying solar radiation throughout the day; the fluid layer of solid particles acts like a thermal flywheel, allowing for excellent heat conduction, considerable heat capacity with a homogeneous temperature field, and the ability to absorb heat shocks not only due to the temperature resistance of the solid particles, but also due to the high thermal diffusivity, continuous renewal of the material exposed to concentrated solar radiation, and continuous mixing of the fluidized solid particles, which provides sufficient residence time for the particles to reach the desired temperature level for use.

[0027] The present invention is also applicable to configurations in which a thermal resistor or thermally equivalent means is immersed in or in thermal contact with the fluidized bed of particles, i.e., the input of thermal power in the bed is by the Joule effect (and therefore by electricity), by a high temperature heat transfer fluid, by waste heat, or a combination of these. In particular, said bed heating means may use low cost electrical energy, for example derived from renewable sources, in particular wind or photovoltaic energy, or residual thermal energy that is thermal waste from industrial processes.

[0028] The present invention is also applicable to hybrid solutions where the thermal energy input to the formation comes from a combination of different sources such as solar radiation, electricity, heat transfer fluids, waste heat, etc.

[0029] Additional advantages, features and modes of use of the invention will arise and become apparent from the following detailed description of some of its embodiments, disclosed by way of example and not of limitation.

[0030] BRIEF DESCRIPTION OF THE DRAWINGS Reference is made to the accompanying drawings. [Brief explanation of the drawings]

[0031] [Figure 1] 1 shows diagrams previously introduced in the "Background" section of this disclosure. [Figure 2] 1 shows diagrams previously introduced in the "Background" section of this disclosure. [Figure 3] 1 shows diagrams previously introduced in the "Background" section of this disclosure. [Figure 4] 1 shows a block diagram illustrating a conceptual scheme of an embodiment of a heat exchange and thermal energy storage device according to the present invention; [Figure 4A] 5 shows a block diagram illustrating a conceptual scheme of an embodiment of a heat exchange and thermal energy storage system according to the present invention, based on the arrangement shown in FIG. 4. [Figure 5] FIG. 1 shows a block diagram illustrating a conceptual scheme of another embodiment of a heat exchange and thermal energy storage device and system according to the present invention. [Figure 6]5 shows a side view of an embodiment of a heat exchange and thermal energy storage device according to the present invention, based on the arrangement of FIG. 4. [Figure 7] 5 shows a side view of another embodiment of a heat exchange and thermal energy storage device according to the present invention, based on the arrangement shown in FIG. 4. [Figure 8A] 5 shows a side view of a further embodiment of a heat exchange and thermal energy storage device according to the invention, based on the arrangement shown in FIG. 4. [Figure 8B] 5 shows a top view of a further embodiment of a heat exchange and thermal energy storage device according to the invention, based on the arrangement shown in FIG. 4. [Figure 9] 5 shows a side view of a possible method for reintroducing solid particles into a fluid layer in the presence of highly concentrated solar radiation, based on the arrangement shown in FIG. 4. DETAILED DESCRIPTION OF THE INVENTION

[0032] Detailed Description of the Preferred Embodiments of the Invention Embodiments and variations of the present invention are described below primarily with reference to the figures above.

[0033] In the following detailed description, additional embodiments and variations to embodiments and variations already covered in the same description are presented only in conjunction with the differences to those already presented.

[0034] Furthermore, the various embodiments and variants and relative components, means and elements described below may be used in combination where compatible.

[0035] A heat exchanger 100 according to a preferred embodiment of the present invention is shown conceptually in FIG.

[0036] The apparatus 100 includes a receiver device 1 or receiver for capturing and temperature stabilizing thermal energy in a fluidized bed of solid particles. Such a device is labeled "Receiver" in FIG. 4 above. Heat is provided to the bed by an energy source ("Power" in FIG. 4), such as solar radiation or another energy source. The energy source may include an electrical resistor, such as those shown in the "Overview" section of this disclosure, immersed in or thermally connected to the bed.

[0037] The general configuration of device 1 may be, for example, that disclosed in WO 2017 / 021832 A1, WO 2018 / 142292 A1, WO 2013 / 150347 A1 or WO 2020 / 136456 A1.

[0038] Downstream of device 1 with respect to the physical flow of solid particles is located hot tank 2, which receives the physical flow of hot particles that make up the layer of device 1. Hot tank 2 has the function of storing hot particles for a desired time, and its capacity allows for the desired thermal energy storage. The particles physically transferred from device 1 into hot tank 2 can be the entire layer received by device 1 or a portion of it. The layer will always have its resident mass remaining in device 1, and another vector mass being transferred to hot tank 2 and subsequent elements of apparatus 100. The volumes comprising the two masses can also be adjusted or selected depending on the energy needs. As mentioned above, in preferred applications, the resident mass is zero, which means that the entire layer moves in the thermal circuit as disclosed herein.

[0039] In certain configurations, the fluid layer level in device 1 can be varied or adjusted between a maximum and a minimum level during operation to compensate for possible differences between solid particle velocities entering and exiting the receiver.

[0040] Downstream of the high temperature tank 2 with respect to the heat exchange flow and the particle physical flow is the heat exchanger 3. Thus, in the configuration of the present invention, the heat exchanger 3 is not immersed in the fluid layer but is located outside the device 1.

[0041] The heat exchanger 3 may be based on a heat transfer fluid (HTF), for example steam or (supercritical) CO2. Preferably, the heat exchanger 3 operates in countercurrent, i.e. the bed particles and the HTF flow in opposite directions within the exchanger 3.

[0042] The heat exchanger 3 may include several units operating according to different exchange principles or fluids.

[0043] Downstream of the exchanger 3 is a cold tank 4 which receives the cold solid particles after they have transferred heat to the HTF.

[0044] The apparatus 100 further comprises means for circulating the vector mass of bed particles from the device 1 to the above introduced components 2-4 and back to the device 1. Said means are represented diagrammatically by arrows in Figure 4 and generally indicated by 5. They may be based for example on mechanical conveyors, gravity feed, elevators or other means.

[0045] The local or remote control unit 10 of the apparatus 100 can control or command the various elements introduced above and can determine the operating modes and / or parameters regarding particle flow and heat exchange.

[0046] The control unit 10 may be configured to control the flow of said vector mass within the apparatus based on parameter values ​​preprogrammed and / or detected by parameter detection means 6 located at one or more selected locations of the apparatus 100. In particular, the control unit 10 may adjust the particle mass flow rate into and out of the device 1 according to the available power input in order to keep the detected value of the fluid layer temperature within a desired range. Similarly, the control unit 10 may be configured to control the operation of the heat exchanger 3, in particular by adjusting the solid particle mass flow rate across the heat exchanger, according to the HTF mass flow rate and temperature desired for use.

[0047] Advantageously, all the elements of the apparatus, for example the device 1, the hot and cold tanks 2, 4, the heat exchanger 3 and the associated conducting means, are thermally insulated to limit heat losses.

[0048] The general mode of operation of the device 100 is as follows.

[0049] As explained above, the solid particles, or their vector mass, are not permanently contained within the device 1, but are instead transferred from the device 1 to the hot tank 2, to the heat exchanger 3, to the cold tank 4, and finally recycled back into the device 1.

[0050] The solid particles are heated in the device 1, for example by a solar source, electricity, process heat or the like.

[0051] Once the solid particles reach the desired maximum temperature in the device 1, i.e., once thermal energy has been input in the fluid layer, the solid particles are extracted from the device 1 in batch / separate or continuous mode and transported to the high temperature tank 2.

[0052] The temperature field of the layer of the fluidic device 1 may be continuously monitored by a dedicated thermocouple 6, or other temperature sensor or transducer, preferably in communication with the control unit 10, to enable discharge of the solid particles into the high temperature tank 2 when the temperature of the solid particles reaches a desired value optimal for heat exchanger 3 operation.

[0053] High temperature tank 2 is sized and configured to ensure the desired thermal energy storage capacity. When energy is to be released into the HTF, solid particles are delivered from high temperature tank 2 to external heat exchanger 3. The thermal energy stored in high temperature tank 2 can be released during a simultaneous heat input phase or at a delayed time, depending on the specific process needs, occurring in device 1 based on the resident bed mass.

[0054] An external heat exchanger 3, preferably implemented in a counter-current configuration, receives the hot solid particles, and the HTF exits the heat exchanger 3 at a temperature slightly below that of the hot particles entering the receiver. For example, with reference to the example given in the "Background" section of this disclosure with respect to supercritical CO, supercritical CO can be produced at 700°C, with solid particles at, for example, 720°C as a maximum temperature, thus resolving the criticality highlighted with reference to known art.

[0055] After releasing their heat capacity to the HTF, the solid particles exit the external heat exchanger 3 at a "cold" temperature and are delivered to the cryogenic tank 4, for example, by gravity, a mechanical extraction device, or other means, as mentioned above.

[0056] Cryogenic tank 4 receives solid particles during HTF production and may accumulate particles until the next heating stage in device 1 begins. Cryogenic tank 4 is preferably at least the same size as hot tank 2 so that the heat capacity associated with the entire particle mass stored in hot tank 2 can be released to the HTF in heat exchanger 3.

[0057] Finally, the solid particles are circulated by means 5 from the cryogenic tank 4 back to the device 1 where they are heated again by the power source.

[0058] During the recirculation of the solid particles to the device 1, pre-heating of the solid particles may be provided, for example by electric heaters, radiant burners or other heating means located in the transport conveyor.

[0059] According to a preferred control mode, the mass flow rate of solid particles to be recirculated into device 1 is regulated by the actual amount of input power entering the device. Such control may be performed by control unit 10, for example by a frequency converter adjusting the speed of a mechanical extraction system from a cryogenic tank. As the available input power to device 1 increases / decreases, the particle flow rate recirculated into device 1 may increase / decrease proportionately, thus helping to keep the solid particle temperature inside the device within a desired temperature range.

[0060] According to a variant, device 1 and high temperature tank 2 can be integrated into a single unit or the high temperature tank can be omitted. This variant can be useful, for example, if the HTF is not produced simultaneously with the energy input in device 1, but only in a delay stage.

[0061] In this alternative configuration, cold solid particles recycled from cold tank 4 to the integrated fluidized bed receiver / hot tank device - or to receiver 1 only - load it before the next energy input stage begins, without mixing the cold particles with the hot particles, particularly during HTF production.

[0062] If the device is solar powered, such as in a concentrated solar power system, solar radiation can be introduced into the fluid layer receiver directly from the heliostat field or through secondary reflection, for example by a beam down mirror.

[0063] According to a preferred embodiment of said receiver device 1 shown in Figure 8, the recirculation of solid particles into the receiver can be realized in such a way that solar radiation 200, which preferably enters the receiver through a window 201 in the side wall, impinges on the solid particles 203 while they fall into the device. In this way, the receiver inner surface lining 204 is protected from a particularly strong radiation flux and a first heating of the particles is obtained before they reach the rest of the fluid layer 205, where their heating continues and is completed until the particle temperature reaches the value desired for use.

[0064] Still in the case of concentrated solar systems, the power entering the receiver can be estimated at any time by conventional instrumentation, for example by measuring the actual solar radiation (e.g. DNI, direct solar irradiance) in the heliostat field with a pyranometer and refining it with known optical performance algorithms.

[0065] If the receiver is input with thermal power from electricity (Joule effect), the input power can be estimated by conventional instrumentation such as a wattmeter; similarly, if the receiver is input with heat from a hot fluid, the input power can be derived from conventional hot gas flow and temperature / pressure measurements.

[0066] According to a preferred embodiment of the heat exchange and thermal energy storage system, multiple devices or modules such as those shown in Figure 4 can be arranged in parallel, as shown conceptually in Figure 4A, with the devices designated 101, 102, ..., 10N, respectively. In this embodiment, the hot HTF flows A1, A2, ..., AN produced by each module are combined and delivered to an end user.

[0067] According to another embodiment of the heat exchange system and thermal energy storage shown in Figure 5, several devices or modules 111, 112, ... 11N can be integrated by sharing a heat exchanger 30. In this case, solid particles from each hot tank or from each receiver of each device are conveyed as flows C1, C2, CN to the common heat exchanger 30, from where they are recycled as flows B1, B2, ... , BN back to each respective cold tank.

[0068] The system configuration of Figure 5 can be advantageously used when heat exchangers must be located near high-temperature HTF use areas. For example, in the case of power production by supercritical CO2 turbines, supercritical CO2 must be produced at high temperatures and pressures (e.g., above 700°C and 200 bar, respectively) to enable a highly efficient conversion cycle. These conditions require the use of specialized materials that can withstand the severe thermomechanical stresses resulting from the combination of high temperatures and pressures, particularly in the heat exchangers and for the supercritical CO2 piping from the heat exchangers to the supercritical CO2 turbine. The length of these piping can therefore be minimized with the proposed configuration, risking potential failures and excessive costs.

[0069] Thus, again, referring to FIG. 5, a heat exchanger 30 common to several devices is used in such a way that it can be located in close proximity to the supercritical CO2 turbine in selected applications, Thus, the associated piping length is minimized, while the solid particles are transported to and from the heat exchanger by gravity or other means, for example by a mechanical conveyor.

[0070] Preferred embodiments for one or more elements of the circulation means 5, indicated diagrammatically by arrows in Figures 4-5, will now be described.

[0071] Reliable transport of the solid particles is preferably achieved by a high temperature resistant mechanical conveyor, which is preferably fully enclosed in an outer casing and / or thermally insulated to limit heat loss to the environment. Examples of suitable conveyors, in particular belt conveyors, may be based on the general configurations disclosed, for example, in WO 2007 / 034289 A1 or WO 2017 / 013517 A1.

[0072] An embodiment of an apparatus configuration designated as 100' based on the conceptual scheme of Figure 4 is shown in Figure 6. In this example, the receiver 1, hot tank 2 and heat exchanger 3 are arranged in a tower configuration, while the cold tank 4 is placed to the side, thus limiting the tower height.

[0073] Preferably, the transport of the solid particles from the exchanger 3 to the cryogenic tank 4 and from the cryogenic tank 4 back into the receiver 1 is obtained by a combination of inclined conveyors indicated by 51 and 52 respectively.

[0074] As an example of dimensioning devices and systems in relation to the configuration of FIG. 6, the following is mentioned.

[0075] According to the scheme in Figure 6, the apparatus includes a fluid-bed receiver, a hot tank, a cold tank, and a supercritical CO2 (sCO2) heat exchanger to produce sCO2 that drives a Brayton power cycle turbine (not shown in Figure 6) for power generation. Supercritical CO2 turbines are being developed with the aim of reaching heat-to-electricity conversion efficiencies approaching 50%, but sCO2 is produced continuously at temperatures of approximately 700-720°C (and pressures above 200 bar).

[0076] For example, assuming a CSP plant with a given output for all-day power generation, i.e., when there is no sun, the hot and cold tanks should have sufficient capacity to accumulate solid particles to ensure power generation during the night, while the receiver should be able to capture solar energy during the day and release it into the sCO2 loop for the entire day, and the solid particle recirculation system should be sized to handle the required mass flow rate.

[0077] For example, assuming a power output of 3 MWe, 24 hours of power generation per day (8 hours daytime plus 16 hours nighttime), solid particles with a specific heat capacity of 1200 J / kgK, an sCO2 turbine efficiency of 47%, a 95% efficient solid particle to sCO2 counterflow heat exchanger with a 200°C solid particle temperature reduction (e.g., from 750°C to 550°C), and a receiver efficiency of 85%, the following results: Receiver 1 should be sized to receive an average solar power output of 23.7 MWt during the day. The heat exchanger 3 must be traversed continuously for a full day by 101 t / h of solid particles. The inclined conveyor 51 must handle a solid particle mass flow rate of 101 t / h at 550°C. The high-temperature tank 2 and the low-temperature tank 4 must ensure a capacity of at least 1613 tons with material temperatures of 750°C and 550°C respectively (ignoring small heat losses during transportation); The inclined conveyor 52 must transport solid particles at a rate of 303 t / h from the low-temperature tank 4 to the receiver 1 during the day at 550°C.

[0078] Therefore, solid particles are supplied to receiver 1 at a rate of 303 t / h during the day, and discharged at 303 t / h to high-temperature tank 2 by a dosing device (not shown in Figure 6). For example, assuming a receiver capacity of 300 tons, the solid particles take almost one hour to heat up under an average solar power of 23.7 MWt.

[0079] This time is much longer than other CSP solid particle technologies, and due to the high thermal diffusivity of the fluid layer and the ability to monitor the particle temperature in real time, for example with a thermocouple immersed in the fluid layer, the proposed configuration allows for a much higher degree of temperature stabilization and better control of the solid particles within the desired temperature range before they are fed to the high temperature tank and then to the heat exchanger. Proper temperature control of the solid particles is paramount for the safe operation and high performance of the sCO2 loop.

[0080] FIG. 7 shows an alternative arrangement of an apparatus embodiment, designated 100'', still based on the conceptual scheme of FIG. 4, in which the receiver 1, hot tank 2 and heat exchanger 3 are all arranged in a tower configuration.

[0081] This embodiment is particularly suitable for factories where tower height is not an issue and horizontal land footprint must be minimized.

[0082] Downward transport of solid particles from the various elements can be obtained by gravity and / or mass flow control devices such as dosing valves inserted between adjacent elements 1-2, 2-3 and 3-4. Return upward transport of solid particles can be obtained, for example, by a vertical elevator 53.

[0083] 8A and 8B show a further embodiment of an apparatus configuration, designated herein by 100''', which can still be considered to be roughly based on the conceptual scheme of FIG. 4 or 4A.

[0084] In this configuration, thermal power is input to one or more fluid layer receivers, specifically four receivers designated 11-14 in the illustrated example. The stored thermal energy is then delivered by discharging the respective hot solid particle masses to a common set of heat exchangers 300 and cold tanks 400. Common or separate hot tanks ultimately integrated into each receiver may also be provided.

[0085] Note that in the illustrated example, mechanical conveyors may be used to transfer the particles to exchanger 300. Two of them are shown as 501 and 502 in FIG. 8A by way of example. Similarly, mechanical conveyors and elevators, shown as 21-24, may be used to recirculate the cold solid particles from cold tank 400 to the four receivers 11-14.

[0086] In configurations where a high temperature tank is associated with or integrated with each receiver 11-14, the apparatus 100''' captures and stores thermal energy in the fluid bed receiver during an input phase, keeps the solid particles contained in the receiver / high temperature tank, and later releases the associated particulate mass during an HTF production phase. The delivery of particulate mass from each receiver 11-14 to the common exchanger 300 may or may not be simultaneous, depending on the particular energy production needs and plant configuration.

[0087] The cryogenic tank 400 may have a volume at least equal to the total volume of the receivers 11-14 to contain all vector particle mass before the next injection phase begins.

[0088] Therefore, the apparatus 100''' is suitable for use when the thermal energy input in the receiver and the heat exchange in the exchanger 300, i.e., HTF production, do not occur simultaneously.

[0089] For example, this configuration can be employed in a daytime concentrating solar power system to capture solar energy and generate HTF at a delayed time, typically after sunset. Additionally, this configuration can be used to inject power (e.g., provided by electricity, waste heat, or other sources) into the fluidized bed when the power is available at low cost and is released at a later time rather than simultaneously with the injection step.

[0090] In other words, according to a preferred mode of operation, the cryogenic particles from the cryogenic tank are not recirculated to the fluid layer receiver during the power-on phase, or in any case the power-on and power-exchange phases are shifted in time.

[0091] The present invention further provides a method for storing and transferring thermal energy based on the features already described above in connection with the devices and systems of the present invention.

[0092] The subject matter of the present disclosure has been described above with reference to its preferred embodiments, and it is intended that there may be other embodiments that fall within the same inventive core, all of which fall within the scope of protection of the claims reported below.

Claims

1. 1. A device (100) for the storage and conduction of thermal energy, comprising: At least one thermal energy input device (1) having a fluid layer of solid particles received in a casing and exposed to a thermal energy source to function as a heat storage means; heat exchange means (3) configured for the exchange of thermal energy between the heating vector mass of the particles of said bed and a working fluid, said heat exchange means (3) being configured for countercurrent exchange; transport means (5) configured to deliver the vector mass of particles of the layer from the energy input device (1) to the heat exchange means (3) and to return at least a portion of the vector mass downstream of the heat exchange means (3) to the energy input device (1); a control unit (10) configured to control the flow of said vector mass within said device based on parameter values ​​detected by parameter detection means (6), e.g. temperature sensors, preprogrammed and / or located at one or more selected locations of said device (100); An apparatus (100) comprising:

2. 2. The apparatus (100) of claim 1, wherein the energy input device (1) is configured to heat the particles of the layer by solar radiation impinging either directly or indirectly on the particles of the layer, either with or without a screen means interposed between the particles of the layer and the solar radiation.

3. 3. The apparatus (100) according to claim 1 or 2, wherein the energy input device (1) is configured to heat the particles of the layer by electrical means, in particular by one or more resistors immersed in or thermally connected to the layer of particles and heating them by the Joule effect.

4. The apparatus (100) according to any one of claims 1 to 3, comprising a high temperature tank (2) arranged downstream of or integrated into the or each energy input device (1) and configured as a storage vessel for the vector mass interposed between the energy input device (1) or a part thereof exposed to a power source and the heat exchange means (3).

5. The apparatus (100) according to any one of claims 1 to 4, comprising a cryogenic tank (4) arranged downstream of the heat exchange means (3) and configured as a storage vessel for the vector mass interposed between the heat exchange means (3) and a part of the transport means (5) that returns the vector mass to the energy input device (1).

6. 6. An apparatus (100') according to any one of claims 1 to 5, wherein the or each energy input device (1), the high temperature tank (2), the heat exchange means (3) and / or the low temperature tank (4) have a tower arrangement, with the one or more energy input devices (1) at the top and other elements below them.

7. 7. Apparatus (100) according to claim 5 or 6, wherein the low temperature tank (4) is arranged transversely to the or each energy input device (1), the high temperature tank (2) and / or the heat exchange means (3).

8. The apparatus (100''') comprises a plurality of thermal energy input devices (11-14).

8. The apparatus (100'') according to any one of claims 1 to 7, comprising a plurality of thermal energy input devices (11-14) each having a respective fluid layer of solid particles received in a casing and functioning as a heat storage means upon exposure to a thermal energy source.

9. The apparatus (100''') according to any one of claims 1 to 8, comprising heat exchange means (300) and / or cryogenic tanks (400) common to a plurality of thermal energy input devices (11-14) and configured to be selectively supplied by one or more respective vector masses of said devices.

10. The heat exchange means (3) uses steam, CO as a working fluid. ２ or supercritical CO ２ The apparatus (100') according to any one of claims 1 to 9, configured to operate with

11. Apparatus (100) according to any one of the preceding claims, wherein said transport means (5) comprise one or more mechanical conveyors (51, 52), preferably belt conveyors, and / or one or more elevator devices.

12. A system for the storage and transfer of thermal energy, comprising a plurality of devices (101, 102) according to any one of claims 1 to 11, each arranged parallel to the flow of the working fluid.

13. 1. A method for storing and transferring energy in the form of heat, comprising the steps of: a thermal energy input step in which the fluid layer of solid particles is exposed to an energy source; a heat exchange step in which at least the vector mass of particles of said heated layer is circulated to heat exchange means operating in countercurrent to transfer heat to a working fluid; a transport step of returning the vector mass to the input step; provide A method wherein the vector mass flow is controlled based on preprogrammed and / or sensed parameter values.

14. The method of claim 13 , wherein the energy source is a solar energy source.

15. 15. The method according to claim 13 or 14, wherein the energy source is an electrical energy source, such as electrical energy from renewable energies, or a residual thermal energy source, such as thermal waste from other industrial plants.

16. The working fluid is steam, CO ２ or supercritical CO ２ The method according to any one of claims 13 to 15, wherein

17. 17. The method according to any one of claims 13 to 16, wherein the thermal energy input step is simultaneous with the heat exchange step.

18. A method according to any one of claims 13 to 17, wherein the heat exchange step is delayed relative to any thermal energy input step.

19. A method according to any one of claims 13 to 18, using an apparatus or system according to any one of claims 1 to 12.

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