Thermochemical heat storage device and heat storage system

Abstract

The invention provides a thermochemical heat storage device and a heat storage system. The thermochemical heat storage device comprises a shell, a supporting bed, a heat storage medium ball body and an auxiliary medium ball body. An air inlet located in the bottom area and an air outlet located in the top area are formed in the shell, the supporting bed is provided with a ventilation structure, the supporting bed is arranged in the bottom area of the shell and located above the air inlet, and the auxiliary medium balls and the heat storage medium balls are mixed and stacked on the supporting bed in proportion. The density of the auxiliary medium balls is smaller than that of the heat storage medium balls, and when airflow is introduced into the air inlet, the auxiliary medium balls are pushed by the airflow to enable the heat storage medium balls to roll and flow in the shell. According to the heat storage device, the low-density auxiliary medium ball bodies dynamically stir the heat storage medium ball bodies to roll and flow in the shell under airflow, so that the heat storage medium ball bodies are promoted to be converted from a static accumulation contact heat transfer mode to a forced up-and-down circulation flow heat transfer mode, and the heat transfer efficiency of heat in a heat storage material is enhanced; and the heat efficiency of the thermochemical heat storage device is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of thermochemical energy storage, and particularly provides a thermochemical energy storage device and an energy storage system. Background Art

[0002] Energy storage technology stores thermal energy such as solar thermal energy, geothermal energy, industrial waste heat, and low-grade waste heat by using energy storage materials as a medium, solves the intermittent and unstable disadvantages of renewable energy, as well as the contradiction of the mismatch between the temporal and spatial supply and demand in the process of energy conversion and utilization, and is an effective means to achieve the efficient utilization of renewable energy.

[0003] Thermal energy storage methods include sensible heat energy storage, latent heat energy storage, and thermochemical energy storage. Among them, thermochemical energy storage has advantages such as high energy storage density, long-term energy storage, and long-distance transportation, and is highly compatible with fields such as solar energy storage and industrial high-temperature heat storage. It is also the energy storage method with the highest energy storage density currently.

[0004] Common thermochemical energy storage devices are mostly gas-solid reaction energy storage systems, and the energy storage materials are usually statically stacked in the energy storage tank. In the actual application process, when the energy storage materials are statically stacked, the heat transfer in the energy storage materials is slow and inefficient, reducing the energy storage / discharge effect of the thermochemical energy storage device. Summary of the Invention

[0005] The purpose of the present invention is to solve the problem of poor heat transfer efficiency in the energy storage materials in the existing thermochemical energy storage device. The purpose of the present invention is achieved by adopting the following technical solutions:

[0006] The present invention provides a thermochemical energy storage device, including: a housing, which is provided with an air inlet in the bottom area and an air outlet in the top area; a support bed, which has a breathable structure, the support bed is arranged in the bottom area of the housing, and the support bed is located above the air inlet; energy storage medium spheres; and auxiliary medium spheres, whose density is less than that of the energy storage medium spheres; the auxiliary medium spheres and the energy storage medium spheres are mixed and stacked on the support bed in proportion; when air flow is introduced through the air inlet, the auxiliary medium spheres are pushed by the air flow to make the energy storage medium spheres tumble and flow in the housing.

[0007] Preferably, the housing includes a first cover body, a second cover body, and a cylindrical main body; the cylindrical main body is erected, the first cover body and the second cover body are hermetically connected to both ends of the cylindrical main body, the support bed is fixed to the lower side of the cylindrical main body, the air outlet is arranged on the first cover body, the air inlet is arranged on the second cover body, and the cylindrical main body has a variable diameter structure, and the converging port of the variable diameter structure faces the support bed side.

[0008] Preferably, the cylindrical body includes a first cylinder, a second cylinder, and the diameter-changing structure located between the first cylinder and the second cylinder. The diameter of the first cylinder is greater than that of the second cylinder. The diameter-changing structure is an annular conical surface, and the included angle between the generatrix of the annular conical surface and the plane perpendicular to the axis of the annular conical surface ranges from 45° to 65°.

[0009] Preferably, a plurality of flow guiding plates are provided on the circumferential direction of the inner side wall of the annular conical surface. The plurality of flow guiding plates are all inclined and distributed in the same direction to form a spiral radial shape. The distance between two adjacent flow guiding plates is greater than the diameters of the auxiliary medium spheres and the heat storage medium spheres.

[0010] Preferably, the included angle between the generatrix of the annular conical surface and the flow guiding plate at the position of the generatrix is 5° to 10°.

[0011] Preferably, the number of the auxiliary medium spheres is 10% - 20% of the number of the heat storage medium spheres.

[0012] Preferably, the heat storage medium spheres include at least one of the material systems of Co3O4 / CoO, Mn2O3 / Mn3O4, Pb3O4 / PbO, and CuO / Cu2O.

[0013] Preferably, the auxiliary medium spheres include foam ceramic balls.

[0014] Preferably, the diameter of the heat storage medium spheres is smaller than that of the auxiliary medium spheres, and the diameter of the heat storage medium spheres is not less than 1.5 cm.

[0015] Preferably, the diameter of the auxiliary medium spheres does not exceed 3 cm.

[0016] Preferably, the heat storage device further includes a diverter disposed inside the housing, and the diverter is located between the support bed and the air inlet.

[0017] Preferably, the heat storage device further includes a shielding net disposed in the top region of the housing, and the shielding net is located below the air outlet.

[0018] Preferably, the heat storage device further includes a feed port, and the feed port is disposed on the upper side wall of the cylindrical body.

[0019] Preferably, the heat storage device further includes a discharge port, and the discharge port is located at the horizontal bottom end of the second cover body.

[0020] Based on the same inventive concept, the present invention further provides a heat storage system, including the thermochemical heat storage device and a flow control device as described above. The flow control device is disposed at the air inlet of the thermochemical heat storage device.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] The present invention provides a thermochemical energy storage device, which includes a housing, a support bed, heat storage medium spheres and auxiliary medium spheres. Among them, the housing is provided with an air inlet in the bottom area and an air outlet in the top area. The support bed has a breathable structure. The support bed is arranged in the bottom area of the housing and above the air inlet. The auxiliary medium spheres and the heat storage medium spheres are mixed and stacked on the support bed in proportion. The density of the auxiliary medium spheres is less than that of the heat storage medium spheres. When air flow is introduced through the air inlet, the auxiliary medium spheres are pushed by the air flow, so that the heat storage medium spheres roll and flow in the housing. This energy storage device uses the dynamic agitation of the low-density auxiliary medium spheres under the air flow to make the heat storage medium spheres roll and flow in the housing, promoting the heat transfer mode of the heat storage medium spheres from static stacking contact to forced up-and-down circulation flow, enhancing the heat transfer efficiency of heat in the heat storage material, and improving the thermal efficiency of the thermochemical energy storage device. Description of the Drawings

[0023] Figure 1 is the overall structural schematic diagram of the thermochemical energy storage device of the present invention;

[0024] Figure 2 is the overall axial sectional schematic diagram of the thermochemical energy storage device of the present invention;

[0025] Figure 3 is the structural schematic diagram of the diverter in the thermochemical energy storage device of the present invention;

[0026] Figure 4 is Figure 1 the sectional view taken along the line A-A in

[0027] Reference numerals: 1 - cylindrical body; 11 - first cylinder; 111 - feed port; 12 - annular conical surface; 121 - guide plate; 13 - second cylinder; 2 - first cover; 21 - air outlet; 3 - second cover; 31 - air inlet; 32 - discharge port; 4 - support bed; 5 - diverter; 6 - heat storage medium spheres; 7 - auxiliary medium spheres; 8 - shielding net. Detailed Embodiments

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] In the description of the present invention, it should be noted that the terms used to indicate the orientation or positional relationship in the text are based on the orientation or positional relationship shown in the drawings. This is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0030] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] Example 1

[0032] As Figure 1 and Figure 2 shown, the thermochemical energy storage device of the embodiment of the present invention includes a housing, a support bed 4, a shielding net 8, a diverter 5, a heat storage medium sphere 6, and an auxiliary medium sphere 7. Among them, the housing is provided with an air inlet 31, an air outlet 21, a feed inlet 111, and a discharge outlet 32. Both the air inlet 31 and the discharge outlet 32 are located in the bottom area of the housing, the air outlet 21 and the feed inlet 111 are both located in the top area, the support bed 4 has a breathable structure, the support bed 4 is arranged in the bottom area of the housing and above the air inlet 31, the shielding net 8 is arranged in the top area of the housing, the shielding net 8 is located below the air outlet 21, the diverter 5 is arranged between the support bed 4 and the air inlet 31, the auxiliary medium spheres 7 and the heat storage medium spheres 6 are mixed and stacked on the support bed 4 in proportion, and the density of the auxiliary medium spheres 7 is less than the density of the heat storage medium spheres 6. When air flow is introduced through the air inlet 31, the auxiliary medium spheres 7 are driven by the air flow so that the heat storage medium spheres 6 roll and flow up and down in the housing.

[0033] It can be understood that during the heat storage and heat release processes of the energy storage device, under the dynamic agitation of the high-speed air flow, the low-density auxiliary medium spheres 7 can change the contact mode of the heat storage medium spheres 6 from the static stacking contact mode to the up-and-down circulating flow contact mode, enhancing the heat transfer efficiency in the heat storage material and accelerating the reaction rate of the heat storage medium spheres 6.

[0034] Specifically, as Figures 1 to 4As shown, in the embodiment of the present invention, the housing includes a first cover 2, a second cover 3, and a cylindrical body 1. The cylindrical body 1 is erected, and the first cover 2 and the second cover 3 are hermetically connected to both sides of the cylindrical body 1. The air outlet 21 is provided on the first cover 2, and the air inlet 31 is provided on the second cover 3. The support bed 4 is fixed to the lower side of the cylindrical body 1, and the shielding net 8 is fixed to the upper side of the housing to prevent the spheres from being carried into the air outlet 21 by the air flow. The two types of spheres flow up and down in the space between the shielding net 8 and the support bed 4. It should be noted that the support bed 4 adopts a mesh structure, and the mesh holes of the support bed 4 and the shielding net 8 are both smaller than the diameters of the auxiliary medium spheres 7 and the heat storage medium spheres 6.

[0035] Among them, both the first cover 2 and the second cover 3 adopt a conical structure. The air outlet 21 is provided at the horizontal top end of the first cover 2 (the converging opening of the conical structure), the discharge port 32 is located at the horizontal bottom end of the second cover 3 (the converging opening of the conical structure), the air inlet 31 is formed on the side surface of the conical structure of the second cover 3, and the feed port 111 is provided on the upper side wall of the cylindrical body 1. The air inlet 31, the air outlet 21, the feed port 111, and the discharge port 32 are all interfaces with a flange structure for docking with the downstream and upstream gas and material transportation structures. Temperature sensors (not shown in the figure) are provided at both the air inlet 31 and the air outlet 21 to compare the temperature changes at the air inlet 31 and the air outlet 21.

[0036] As Figure 1 and Figure 2 shown, a diameter-changing structure is provided on the cylindrical body 1, and the converging opening of the diameter-changing structure faces the support bed 4 side.

[0037] It can be understood that when the air flow passes upward from the converging opening of the diameter-changing structure, after the middle part of the stacked spheres, the auxiliary medium spheres 7 and the heat storage medium spheres 6 flow upward to the open area, the two types of spheres can flow downward along the side wall of the cylinder body, that is, the diameter-changing structure enables the middle area and the outer area of the stacked spheres to form an up-and-down circulation flow pattern of internal rising and external falling, further enhancing the contact convection effect of the two types of spheres in the housing chamber.

[0038] As Figure 1 and 2 shown, the cylindrical body 1 in the embodiment of the present invention includes a first cylinder body 11, a second cylinder body 13, and a diameter-changing structure located between the first cylinder body 11 and the second cylinder body 13. The diameter of the first cylinder body 11 is larger than the diameter of the second cylinder body 13, the diameter-changing structure is an annular conical surface 12, and the angle between the generatrix of the annular conical surface 12 and the plane perpendicular to the axis of the annular conical surface 12 ( Figure 1 the angle a in

[0039] Specifically, the first cylinder 11, the annular conical surface 12, and the second cylinder 13 are connected in sequence from top to bottom. Among them, the upper end of the first cylinder 11 is hermetically connected to the first cover 2, and the lower end of the second cylinder 13 is hermetically connected to the second cover 3.

[0040] It should be noted that, according to actual applications, other structures can also be adopted for the annular surface at the variable diameter structure. For example, the generatrix of the annular surface is a curved structure. Preferably, the variable diameter structure in the embodiment of the present invention is the annular conical surface 12 to reduce the preparation cost.

[0041] In addition, according to actual applications, those skilled in the art can also construct the first cylinder 11, the annular conical surface 12, and the second cylinder 13 into an integral structure. Among them, the axial cross-sections of the first cylinder 11, the annular conical surface 12, the second cylinder 13, the first cover 2, and the second cover 3 are all circular, and the materials are all made of heat-resistant steel.

[0042] As Figure 3 shown, in the embodiment of the present invention, the flow divider 5 is a disc structure, and a plurality of through holes are evenly and symmetrically distributed on the disc structure. When the air flow passes through the through holes of the flow divider 5, it can provide an air flow with a uniform distribution of flow, avoiding the occurrence of gas flow dead zones and reducing the flow effect of the auxiliary medium sphere 7 and the heat storage medium sphere 6.

[0043] In the embodiment of the present invention, the heat storage medium sphere 6 is made of a metal oxide thermochemical heat storage material, which includes at least one of the material systems of Co3O4 / CoO, Mn2O3 / Mn3O4, Pb3O4 / PbO, and CuO / Cu2O. The auxiliary medium sphere 7 is made of a foam ceramic material, preferably an alumina foam ceramic ball, and the pores on the surface of the foam ceramic ball are connected through internal pores. When the alumina foam ceramic balls are filled in the pores between the heat storage medium spheres 6, the air flow can make full heat exchange contact with the surrounding heat storage medium spheres 6 by virtue of the pore structure, enhancing the heat storage / heat release efficiency.

[0044] The diameter of the heat storage medium sphere 6 is smaller than the diameter of the auxiliary medium sphere 7. The diameter of the heat storage medium sphere 6 is not less than 1.5 cm, which ensures the heat exchange contact area with the air flow medium and accelerates the reaction rate of the thermochemical heat storage material in the heat storage medium sphere 6. The diameter of the auxiliary medium sphere 7 does not exceed 3 cm, which ensures the driving ability for the heat storage medium sphere 6. The number of the auxiliary medium spheres 7 is 10%-20% of the number of the heat storage medium spheres 6.

[0045] Exemplarily, the number of the heat storage medium spheres 6 is 10,000, and the filling number of the auxiliary medium spheres 7 is 1,000 - 2,000. It should be noted that the heat storage medium spheres 6 and the auxiliary medium spheres 7 are configured proportionally according to the application scenario to balance the heat storage density and good fluidity of the heat storage device.

[0046] In addition, the outer sides of the first cylinder 11, the annular conical surface 12, and the second cylinder 13 are wrapped with heat-insulating materials (not shown in the figure) to reduce heat dissipation loss during the heat storage process. The heat-insulating materials are made of calcium silicate or aluminum silicate ceramic fiber blanket materials.

[0047] As Figure 2 shown, after the thermochemical energy storage device is assembled, the heat storage medium spheres 6 and the auxiliary medium spheres 7 are filled into the support bed 4 evenly stacked in the shell through the feed port 111 in proportion.

[0048] Heat storage operation: When the heat-carrying gas flow (steam) passes through the intake port 31 from bottom to top at high speed through the shunt 5 and blows the auxiliary medium spheres 7 through the support bed 4, the metal oxide heat storage material in the heat storage medium spheres 6 absorbs heat from the heat-carrying gas flow and undergoes a thermochemical decomposition reaction to realize the storage of heat. The heat-carrying gas flow drives the auxiliary medium spheres 7, which in turn drives the heat storage medium spheres 6 to roll up and down in convection. The variable-diameter structure and the auxiliary medium spheres 7 can make the heat storage medium spheres 6 roll and flow more violently, greatly accelerating the reaction rate of the thermochemical heat storage material.

[0049] The gas flow after heat exchange finally passes through the shielding net 8 and is discharged from the outlet 21. When the temperature difference between the intake port 31 and the outlet 21 is detected to be within a stable range, the supply of the heat-carrying gas flow is stopped to end the heat storage operation.

[0050] Heat release operation: A reaction gas flow is introduced into the intake port 31, and the reaction gas flow reacts with the heat storage medium spheres 6 to release heat. Among them, the reaction gas flow includes a mixed gas of nitrogen and oxygen or a mixed gas of nitrogen and air. Among them, the working process principle of the heat release operation is similar to that of the heat storage operation, so it will not be elaborated here.

[0051] Embodiment 2

[0052] As Figure 4 shown, the difference between the thermochemical heat storage device provided in the embodiment of the present invention and that of Embodiment 1 is as follows:

[0053] In the embodiment of the present invention, a plurality of guide plates 121 are further provided on the circumferential direction of the inner side wall of the annular conical surface 12. The guide plates 121 are all arranged in the same inclined direction to form a spiral radial structure. The interval distance between two adjacent guide plates 121 is greater than the diameters of the auxiliary medium spheres 7 and the heat storage medium spheres 6. The included angle between the generatrix of the annular conical surface 12 and the guide plate 121 located at the generatrix position is 5°-10°. Among them, the guide plate 121 is a rectangular strip structure, the guide plate 121 is perpendicular to the annular conical surface 12, the length of the guide plate 121 does not exceed the length of the generatrix of the annular conical surface 12, and the height of the guide plate 121 is between the diameters of the auxiliary medium spheres 7 and the heat storage medium spheres 6.

[0054] With such a setting, when the two types of spheres move downward from the edge of the first cylinder 11 to the annular conical surface 12, with the help of the flow guide plate 121, the two types of spheres can achieve axial rotational flow during the movement towards the center, thereby making the contact convection effect of the entire stacked spheres in the shell better.

[0055] Embodiment 3

[0056] Based on the same inventive concept, the embodiment of the present invention further provides a heat storage system, which includes a flow control device and the thermochemical heat storage device in Embodiment 1 above. The flow control device is arranged at the air inlet of the thermochemical heat storage device to adjust the flow rate of the air flow entering the air inlet.

[0057] The flow control device includes a flow control valve or a flow control pump, and controls the flow efficiency of the stacked heat storage medium spheres 6 in the thermochemical heat storage device by controlling the flow rate of the air flow entering the air inlet, thereby controlling the heat storage / discharge efficiency.

[0058] The above are only the embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention are included within the scope of the claims of the present invention pending approval.

Claims

1. A thermochemical energy storage device, characterized in that, Comprising: A housing, provided with an air inlet (31) in the bottom area and an air outlet (21) in the top area thereon; A support bed (4), having a breathable structure, the support bed (4) being arranged in the bottom area of the housing, and the support bed (4) being located above the air inlet (31); A heat storage medium sphere (6); and An auxiliary medium sphere (7), whose density is less than the density of the heat storage medium sphere (6); The auxiliary medium spheres (7) and the heat storage medium spheres (6) are mixed and stacked on the support bed (4) in proportion; When an air flow is introduced through the air inlet (31), the auxiliary medium spheres (7) are pushed by the air flow to cause the heat storage medium spheres (6) to roll and flow in the housing.

2. The thermochemical energy storage device according to claim 1, wherein The housing includes a first cover body (2), a second cover body (3) and a cylindrical body (1); The cylindrical body (1) is erected, the first cover body (2) and the second cover body (3) are hermetically connected to both ends of the cylindrical body (1), the support bed (4) is fixed to the lower side of the cylindrical body (1), the air outlet (21) is arranged on the first cover body (2), the air inlet (31) is arranged on the second cover body (3), the cylindrical body (1) has a variable diameter structure, and the converging port of the variable diameter structure faces the support bed (4) side.

3. The thermochemical energy storage device according to claim 2, wherein The cylindrical body (1) includes a first cylindrical body (11), a second cylindrical body (13) and the variable diameter structure located between the first cylindrical body (11) and the second cylindrical body (13), the diameter of the first cylindrical body (11) is larger than the diameter of the second cylindrical body (13), the variable diameter structure is an annular conical surface (12), and the included angle range between the generatrix of the annular conical surface (12) and the plane perpendicular to the axis of the annular conical surface (12) is 45° - 65°.

4. The thermochemical energy storage device according to claim 3, characterized in that, A plurality of flow guiding plates (121) are arranged on the circumferential direction of the inner side wall of the annular conical surface (12), and the plurality of flow guiding plates (121) are all inclined and distributed in the same direction to form a spiral radial shape, and the interval distance between two adjacent flow guiding plates (121) is larger than the diameters of the auxiliary medium sphere (7) and the heat storage medium sphere (6).

5. The thermochemical energy storage device according to claim 4, wherein The included angle between the generatrix of the annular conical surface (12) and the flow guiding plate (121) at the position of the generatrix is 5° - 10°.

6. The thermochemical energy storage device according to claim 1, wherein The number of the auxiliary medium spheres (7) is 10% - 20% of the number of the heat storage medium spheres (6).

7. The thermochemical energy storage device according to claim 1, characterized in that, The heat storage medium sphere (6) includes at least one of the material systems of Co3O4 / CoO, Mn2O3 / Mn3O4, Pb3O4 / PbO and CuO / Cu2O.

8. The thermochemical energy storage device according to claim 1, wherein The auxiliary medium sphere (7) includes a foam ceramic ball.

9. The thermochemical energy storage device according to claim 1, characterized in that, The diameter of the heat storage medium sphere (6) is less than the diameter of the auxiliary medium sphere (7), and the diameter of the heat storage medium sphere (6) is not less than 1.5 cm.

10. The thermochemical energy storage device according to claim 9, characterized in that, The diameter of the auxiliary medium sphere (7) does not exceed 3 cm.

11. The thermochemical energy storage device according to claim 1, characterized in that, The heat storage device further includes a flow divider (5) arranged in the housing, and the flow divider (5) is located between the support bed (4) and the air inlet (31).

12. The thermochemical energy storage device according to claim 1, characterized in that, The heat storage device further includes a shielding net (8) disposed in the top region of the housing, and the shielding net (8) is located below the air outlet (21).

13. The thermochemical energy storage device according to claim 2, wherein, The heat storage device further includes a feed inlet (111), and the feed inlet (111) is disposed on the upper side wall of the cylindrical body (1).

14. The thermochemical energy storage device according to claim 2, wherein, The heat storage device further includes a discharge port (32), and the discharge port (32) is located at the horizontal bottom end of the second cover body (3).

15. A heat storage system, characterized in that, It includes the thermochemical heat storage device and the flow control device according to any one of claims 1 to 14, and the flow control device is disposed at the air inlet (31) of the thermochemical heat storage device.

Images