JP2010249412A - Heat storage device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat storage device capable of reducing an unreacted part of a filling layer, and reducing a thermal distribution inside of the filling layer. <P>SOLUTION: This heat storage device has the filling layer 40 filled with heat storage agent particles 43 applying a gas as a reaction medium, internal flow passages 41, 42 formed form the surface of the filling layer 40 to the inside of the filling layer 40 for introducing the reaction medium supplied from the external into the filling layer 40 and releasing the reaction medium led out from the inside of the filling layer 40 to the external, a fluid flow channel 31 spatially separating from the filling layer 40 and the internal flow passages 41, 42 for circulating a heat exchange fluid, and a flat tube 30 having an outer wall face 30c exchanging heat with the filling layer 40, and an inner wall face 30d exchanging heat with the heat exchange fluid, and transferring heat between the filling layer 40 and the heat exchange fluid through the outer wall face 30c and the inner wall face 30d. The internal flow passages 41, 42 are formed in a state of being gradually narrowed from a surface of the filling layer 40 toward the depth. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a heat storage device including a heat storage agent that stores and releases heat by a reversible reaction with a reaction medium.

Conventionally, a chemical heat storage system using a solid-gas reaction such as Ca (OH) ₂ dehydration / CaO addition reaction is known (for example, see Patent Document 1). This chemical heat storage system includes a medium container for storing a reaction medium (H ₂ O), and a reactor including a heat storage agent (CaO) that stores and releases heat by a reversible reaction with the reaction medium. Yes. The medium container and the reactor are connected via a supply pipe for supplying the reaction medium from the medium container to the reactor and a reflux pipe for refluxing the reaction medium from the reactor to the medium container. The reactor has a tubular heat exchanger with a tubular heat exchange wall. The inside of the heat exchange wall of the circular tube heat exchanger is filled with a heat storage agent so as to be in contact with the inner wall surface, and the outside of the heat exchange wall is transferred to the heat exchange fluid (exhaust gas) flowing outside. Fins are provided to increase the thermal area. With these configurations, heat generated by the hydrolysis reaction of CaO can be supplied to the exhaust gas (CaO + H ₂ O → Ca (OH) ₂ , heat dissipation process). Further, heat from the exhaust gas is supplied to Ca (OH) ₂ to regenerate the heat storage agent (Ca (OH) ₂ → CaO + H ₂ O, heat storage process).

JP-A-7-180539

  By the way, in the reactor as described above, the space surrounded by the heat exchange walls is often filled with the heat storage agent particles to form a packed bed. In this case, when water vapor is used as the reaction medium, resistance when the water vapor moves in the packed bed is increased. Moreover, the heat transfer resistance between the heat storage agent particles and the heat exchange wall is also increased. For this reason, there is a problem that a portion where the reaction does not sufficiently proceed occurs in the packed bed or a thermal distribution occurs inside the packed bed.

  The objective of this invention is providing the thermal storage apparatus which can reduce the unreacted part of a packed bed, and can ease the thermal distribution inside a packed bed.

  In order to achieve the above object, the present invention employs the following technical means.

  The invention described in claim 1 includes a packed bed (40) filled with heat storage agent particles (43) composed of a metal oxide capable of reversibly reacting with a gas as a reaction medium, and a packed bed ( The reaction medium formed from the surface of 40) toward the inside of the packed bed (40) and introduced from the outside into the packed bed (40) and led out from the packed bed (40) An internal flow passage (41, 42) that discharges the water to the outside, and a fluid flow path (31) that is spatially isolated from the packed bed (40) and the internal flow passage (41, 42) and that circulates the heat exchange fluid. A first heat exchange surface (30c) for heat exchange with the packed bed (40) and a second heat exchange surface (30d) for heat exchange with the heat exchange fluid, and the first and second heat exchange Heat is transferred between the packed bed (40) and the heat exchange fluid via the faces (30c, 30d). And the internal flow passages (41, 42) are formed so as to gradually narrow from the surface of the packed bed (40) toward the back. It is.

  According to the present invention, the reaction medium supplied from the outside is led into the packed bed (40) mainly through the internal flow passages (41, 42), and diffuses throughout the packed bed (40). Since the internal flow passages (41, 42) are formed so as to gradually narrow from the surface of the packed bed (40) toward the back, the flow velocity of the reaction medium flowing in the internal flow passages (41, 42) is It gets bigger as you go deeper. Thereby, since the diffusion control of the reaction medium is relaxed, the reaction medium can be more effectively diffused in the packed bed (40). Therefore, since the unreacted part of the packed bed (40) can be reduced, the thermal distribution inside the packed bed (40) can be relaxed.

  In the invention according to claim 2, the packed bed (40) is sintered and bonded to the first heat exchange surface (30c), and the metal particles (43) holding the heat storage agent particles (43). 44) or metal fibers (45).

  By mixing the metal particles (44) or the metal fibers (45) in the packed bed (40), a thermal network can be formed across the packed bed (40). Therefore, the thermal distribution inside the packed bed (40) can be further relaxed, and the unreacted portion of the packed bed (40) can be further reduced. Further, since the heat storage agent particles (43) are held by the metal particles (44) or the metal fibers (45), the internal flow passages (41, 42) can be formed with high accuracy, and the formed internal flow passages. The shape of (41, 42) can be maintained.

  According to the third aspect of the present invention, in the packed bed (40), as the distance from the first heat exchange surface (30c) increases, the metal particles (44) or the metal fibers (45) with respect to the weight of the heat storage agent particles (43). ) Is configured such that the weight ratio is lower.

  Thereby, the ratio of the weight of the metal particles (44) or the metal fibers (45) in the packed bed (40) can be increased as the distance from the first heat exchange surface (30c) becomes closer. Therefore, the packed bed (40) and the first heat exchange surface (30c) can be reliably bonded, and the heat transfer resistance between the packed bed (40) and the first heat exchange surface (30c) is reduced. it can.

  The invention according to claim 4 is configured such that the packed bed (40) has a larger aspect ratio of the metal particles (44) as the distance from the first heat exchange surface (30c) increases. It is characterized by.

  Since the void can be made larger as the aspect ratio of the metal particles (44) to be filled becomes larger, the porosity of the packed layer (40) can be made higher as the distance from the first heat exchange surface (30c) becomes longer. it can. Thereby, the movement resistance when the reaction medium permeates into the packed bed (40) from the internal flow path (41, 42) can be lowered toward the internal flow path (41, 42) where the flow rate of the reaction medium is large. it can. Therefore, the reaction medium can be effectively diffused throughout the packed bed (40).

  In the invention according to claim 5, the packed bed (40) is configured such that the distance between the particles of the metal particles (44) becomes larger as the distance from the first heat exchange surface (30c) increases. It is characterized by that.

  Since the voids can be made larger as the interparticle distance of the metal particles (44) to be filled becomes larger, the porosity of the packed layer (40) should be made higher as the distance from the first heat exchange surface (30c) becomes longer. Can do. Thereby, the movement resistance when the reaction medium permeates into the packed bed (40) from the internal flow path (41, 42) can be lowered toward the internal flow path (41, 42) where the flow rate of the reaction medium is large. it can. Therefore, the reaction medium can be effectively diffused throughout the packed bed (40).

  In the invention according to claim 6, the packed bed (40) is configured such that the particle diameter of the heat storage agent particles (43) becomes larger as the distance from the first heat exchange surface (30c) increases. It is characterized by that.

  Since the voids can be made larger as the particle diameter of the heat storage agent particles (43) to be filled becomes larger, the porosity of the packed bed (40) should be increased as the distance from the first heat exchange surface (30c) becomes longer. Can do. Thereby, the movement resistance when the reaction medium permeates into the packed bed (40) from the internal flow path (41, 42) can be lowered toward the internal flow path (41, 42) where the flow rate of the reaction medium is large. it can. Therefore, the reaction medium can be effectively diffused throughout the packed bed (40).

  In addition, the code | symbol in the bracket | parenthesis of each said means has shown an example of the corresponding relationship with the specific means as described in embodiment mentioned later.

It is a schematic diagram which shows the structure of the thermal storage apparatus in 1st Embodiment. It is sectional drawing in the II-II line | wire of FIG. It is a typical expanded sectional view of the flat tube tube wall vicinity of the heat storage apparatus in 1st Embodiment. It is a typical expanded sectional view of the flat tube tube wall vicinity of the heat storage apparatus in the modification of 1st Embodiment. It is a figure which shows the structure of the flat tube tube wall vicinity of the thermal storage apparatus in 2nd Embodiment. It is a figure which shows the structure of the flat tube tube wall vicinity of the thermal storage apparatus in 3rd Embodiment. It is a figure which shows the structure of the flat tube pipe wall vicinity of the thermal storage apparatus in 4th Embodiment. It is a figure which shows the structure of the flat tube pipe wall vicinity of the thermal storage apparatus in 5th Embodiment.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram illustrating a configuration of a heat storage device 1 according to the present embodiment. 2 is a cross-sectional view taken along line II-II in FIG. As shown in FIG.1 and FIG.2, the thermal storage apparatus 1 has the outer side case 10 which comprises a container body, and the flat heat storage core 20 stored in the outer side case 10. As shown in FIG.

  The outer case 10 is provided with an inlet / outlet port 11 through which the reaction medium flows in / out. The reaction medium flows into the outer case 10 from a reaction medium container (not shown) through the outflow inlet 11, and the reaction medium flows out into the reaction medium container through the outflow inlet 11.

  The heat storage core 20 includes a pair of header tanks 21 and 22 and a core portion 23 sandwiched between the header tanks 21 and 22. The internal space of one header tank 21 is separated by a separator 24 provided at the center in the longitudinal direction. Thus, the header tank 21 is divided into an inlet tank portion 25 and an outlet tank portion 26. The inlet tank unit 25 is provided with an inlet 27 through which a heat exchange fluid to be heat exchanged with the heat storage agent flows from the outside. The outlet tank part 26 is provided with an outlet 28 for allowing the heat exchange fluid to flow out. Both the inflow port 27 and the outflow port 28 extend outward through the outer case 10.

  The core part 23 has a plurality of flat tubes 30 whose both ends are connected to both header tanks 21 and 22 (in FIG. 1 and FIG. 2, six flat tubes 30 are shown). The flat tube 30 is made of metal, for example, made of Cu. Inside the flat tube 30, a fluid flow path 31 is formed for circulating the heat exchange fluid. Almost half (three in FIG. 1 and FIG. 2) of the fluid flow paths 31 of the flat tubes 30 a communicate between the inlet tank portion 25 of the header tank 21 and the header tank 22. The fluid flow paths 31 of the remaining flat tubes 30 b communicate between the outlet tank portion 26 of the header tank 21 and the header tank 22. As a result, the heat exchange fluid flows from the outside into the inlet tank portion 25 via the inflow port 27, flows through the fluid flow path 31 of the flat tube 30 a, and flows into the header tank 22. The heat exchange fluid that has flowed into the header tank 22 flows through the fluid flow path 31 of the flat tube 30 b, flows into the outlet header portion 26, and flows out through the outlet 28.

  Filled layers 40 are formed in the gaps between the flat surfaces facing each other in the adjacent flat tubes 30. Thereby, the core part 23 becomes the structure by which the flat tube 30 and the filling layer 40 were laminated | stacked alternately. The packed bed 40 is formed by filling mixed particles obtained by mixing heat storage agent particles and metal particles. The metal particles are preferably made of the same or equivalent metal as the flat tube 30. Here, the equivalent metal means that there is a relationship between a single metal and an alloy containing the metal as a component, or an alloy having the same main component. Each packed bed 40 is thermally connected to the tube wall (heat exchange wall) of the flat tube 30 adjacent to both sides. Each packed bed 40 is spatially isolated from the fluid flow path 31 by the tube wall of the flat tube 30.

The heat storage agent particles are made of a metal oxide that stores and releases heat by using a gas (for example, H ₂ O) as a reaction medium and performing a reversible reaction with the reaction medium. In this metal oxide, an exothermic reaction represented by chemical reaction formula (1) proceeds at a relatively low temperature, and an endothermic reaction represented by chemical reaction formula (2) proceeds at a relatively high temperature. In the formula, (s) represents a solid phase, and (g) represents a gas phase.
XO (s) + H ₂ O (g) → X (OH) ₂ (s) + Q (exotherm) (1)
X (OH) ₂ (s) → XO (s) + H ₂ O (g) −Q (endothermic) (2)
The packed bed 40 includes an internal flow passage 41 extending inward from one surface 23a side of the core portion 23, and an internal flow passage 42 extending inward facing the internal flow passage 41 from the other surface 23b side. Is formed. Each of the internal flow passages 41 and 42 is located in a plane that is substantially at the center between adjacent flat surfaces of adjacent flat tubes 30 and is substantially parallel to each flat surface. The internal flow passages 41 and 42 are formed in a V-shaped cross section so as to become gradually narrower from the inlet of the surface of the packed bed 40 toward the back (terminal). The ends of the internal flow passages 41 and 42 face each other. During the exothermic reaction, the reaction medium supplied from the outside is mainly introduced into the packed bed 40 through the internal flow passages 41 and 42, and during the endothermic reaction, the reaction medium led out from the packed bed 40 is mainly used for internal circulation. It is discharged to the outside through the paths 41 and 42.

  Here, the internal flow passages 41 and 42 may be formed continuously in the vertical direction of FIG. In this case, the internal flow passages 41 and 42 are formed in a groove shape (wedge shape) having a V-shaped cross section extending in the vertical direction in FIG. Further, the internal flow passages 41 and 42 may be a plurality of holes arranged at predetermined intervals in the vertical direction of FIG. In this case, each of the plurality of internal flow passages 41 and 42 has, for example, a conical or pyramidal shape.

  As an example of the formation procedure of the packed bed 40 and the internal flow passages 41 and 42, first, mixed particles obtained by mixing the heat storage agent particles 43 and the metal particles 44 are filled in the gaps between the flat tubes 30, and the metal particles 44 and the metal The filling layer 40 is formed by sintering and bonding the particles 44 and the flat tube 30, and then the filling layer 40 is cut out to form tapered internal flow passages 41 and 42.

  FIG. 3 is a schematic enlarged sectional view of the vicinity of the tube wall of the flat tube 30 of the heat storage core 20. The outer wall surface 30c of the flat tube 30 that is thermally connected to the packed bed 40 is a first heat exchange surface that exchanges heat with the packed bed 40. On the other hand, the inner wall surface 30d facing the fluid flow path 31 of the flat tube 30 is a second heat exchange surface where heat exchange with the heat exchange fluid is performed. The flat tube 30 functions as a heat exchange part that transfers heat between the packed bed 40 and the heat exchange fluid via the outer wall surface 30c and the inner wall surface 30d.

  The packed bed 40 includes a plurality of heat storage agent particles 43 and a plurality of metal particles 44. The metal particles 44 adjacent to each other are bonded relatively firmly by sintering. Further, the metal particles 44 in the vicinity of the outer wall surface 30c of the flat tube 30 are bonded to the outer wall surface 30c relatively firmly by sintering. Thereby, a thermal network is formed over every corner of the packed bed 40. The heat storage agent particles 43 are surrounded and held by surrounding metal particles 44.

  The reaction medium supplied from the outside is mainly introduced into the packed bed 40 via the internal flow passages 41 and 42 having a relatively low movement resistance, and then passes through the gap between the particles having a higher movement resistance. It diffuses throughout the packed bed 40. In the present embodiment, since the internal flow passages 41 and 42 are formed in a plane parallel to the outer wall surface 30c of the flat tube 30, the reaction medium that diffuses through the voids between the particles is as shown in FIG. Generally, it circulates in a direction intersecting the outer wall surface 30c.

  Next, operation | movement of the thermal storage apparatus in this embodiment is demonstrated. First, a heat dissipation process performed to heat a relatively low temperature heat exchange fluid will be described. In the heat dissipation process, the reaction medium is supplied from the reaction medium container into the outer case 10. The reaction medium supplied into the outer case 10 is first introduced into the packed bed 40 mainly through the internal flow passages 41 and 42 having a relatively low movement resistance. Thereafter, the reaction medium in the internal flow passages 41 and 42 passes through the gaps between the heat storage agent particles 43 and the metal particles 44, and mainly in the direction from the internal flow passages 41 and 42 toward the outer wall surface 30c of the flat tube 30. Spread. As a result, the reaction medium penetrates the entire packed bed 40.

  In each heat storage agent particle 43 in the packed bed 40, the exothermic reaction shown in the chemical reaction formula (1) proceeds by supplying the reaction medium. The reaction heat generated in each heat storage agent particle 43 is transmitted to the flat tube 30 through a thermal network formed by the metal particles 44. The heat transferred to the flat tube 30 is transferred to the heat exchange fluid flowing through the fluid flow path 31 in the flat tube 30. Thereby, the heat exchange between the packed bed 40 and the heat exchange fluid is performed via the flat tube 30, and the heat exchange fluid is heated by the reaction heat of the heat storage agent.

  Next, the heat storage process performed in order to reproduce | regenerate a heat storage agent is demonstrated. In the heat storage process, heat from a relatively high temperature heat exchange fluid is transferred to the flat tube 30 and supplied to the entire packed bed 40 through a thermal network formed by the metal particles 44. In the heat storage agent particles 43, the endothermic reaction shown in the chemical reaction formula (2) proceeds using the supplied heat. Thereby, regeneration of a thermal storage agent is performed. The reaction medium released from the heat storage agent particles 43 by the endothermic reaction is released from the heat storage core 20 through the voids between the particles in the packed bed 40 and the internal flow passages 41 and 42.

  In the present embodiment, internal flow passages 41 and 42 are formed from the surface of the packed bed 40 toward the inside. For example, in the heat dissipation process, the reaction medium supplied from the outside is led into the packed bed 40 mainly through the internal flow passages 41 and 42, and then flattened from the internal flow passages 41 and 42 through the voids between the particles. It diffuses in a direction toward the outer wall surface 30c of the tube 30. As the reaction medium diffuses, the heat storage agent particles 43 filled in the packed bed 40 are sequentially directed from the surface side to the inside of the packed bed 40 and from the inner flow passages 41 and 42 to the outer wall surface 30c. I will react. Since the internal flow passages 41 and 42 are formed so as to become gradually narrower from the entrance to the surface of the packed bed 40 toward the back, the flow velocity of the reaction medium flowing through the internal flow passages 41 and 42 becomes larger toward the back. can do. Thereby, since the diffusion rate limiting of the reaction medium is relaxed, the reaction medium can be more effectively diffused in the packed bed 40. Therefore, since the unreacted portion of the packed bed 40 can be reduced, the thermal distribution inside the packed bed 40 can be relaxed.

  In the present embodiment, the presence of the metal particles 44 forms a thermal network from the flat tube 30 to every corner of the packed bed 40. Thereby, since heat transfer in the packed bed 40 is promoted, heat can be quickly removed from the packed bed 40 in the heat dissipation process, and heat can be quickly distributed throughout the packed bed 40 in the heat storage process. be able to. As a result, the thermal distribution of the entire packed bed 40 can be further relaxed, and the unreacted portion of the packed bed 40 can be further reduced.

  Furthermore, in the present embodiment, the heat storage agent particles 43 can be well fixed by the presence of the metal particles 44 that are sintered and bonded to each other. Therefore, the shape of the packed bed 40 can be more easily processed as compared with a packed bed in which the metal particles 44 are not mixed and only the heat storage agent particles 43 are filled. Therefore, the tapered shape of the internal flow passages 41 and 42 can be formed with high accuracy, and the shape of the formed internal flow passages 41 and 42 can be maintained. In addition, since the heat storage agent particles 43 are fixed favorably by the metal particles 44, the mechanical collapse of the packed bed 40 can be suppressed even if a volume change occurs in the heat storage agent particles 43 due to an exothermic / endothermic reaction.

  In the present embodiment, at least the outer wall surface 30c of the flat tube 30 and the metal particles 44 are made of the same or equivalent metal. Therefore, the outer wall surface 30c and the metal particles 44 can be easily bonded by sintering. In addition, thermal strain that can occur between the outer wall surface 30 c and the metal particles 44 can be reduced.

  Furthermore, in the present embodiment, the internal flow passages 41 and 42 of the packed bed 40 are formed so as to gradually narrow from the inlet toward the back. For this reason, compared with the structure by which the width | variety vicinity of the inlet_port | entrance of the internal flow paths 41 and 42 is maintained to the back, the thermal storage agent particle | grains 43 and the metal particle 44 can be filled efficiently.

  Here, in this embodiment, since the internal flow passages 41 and 42 are formed from both surfaces 23a and 23b of the core portion 23, the vicinity of the center between the both surfaces 23a and 23b is the back of the internal flow passages 41 and 42. It has become. For example, when the internal flow passage is formed only from one surface 23a of the core portion 23 and the internal flow passage extends to the vicinity of the other surface 23b, the vicinity of the surface 23b can be the back of the internal flow passage. .

  Next, a modification of this embodiment will be described. FIG. 4 is a schematic enlarged cross-sectional view of the vicinity of the flat tube wall of the heat storage device in the present modification. As shown in FIG. 4, in this modified example, the filling layer 40 is filled with metal fibers 45 instead of or in addition to the metal particles 44. The contacts between the metal fibers 45 and the metal fibers 45 and the outer wall surface of the flat tube 30 are joined by sintering. The heat storage agent particles 43 in the packed bed 40 are held by metal fibers 45.

  When the metal fiber 45 is used as in this modification, since a thermal network as a fiber is formed in advance, it is sufficient that only the metal fiber 45 and the outer wall surface 30c of the flat tube 30 can be joined. Therefore, according to this modification, the thermal network in the filling layer 40 can be more reliably formed, and the joining process can be simplified.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, the ratio of the weight of the metal particles 44 (or metal fibers 45) to the weight of the heat storage agent particles 43 in the packed bed 40 (hereinafter referred to as “the concentration of the metal particles 44”) is a flat tube in which the heat exchange surface is formed. 30 has a feature in that it differs depending on the distance from the outer wall surface 30c. In this embodiment, CaO, Cu, and water vapor are used as the heat storage agent particles 43, the metal particles 44, and the reaction medium, respectively. The flat tube 30 is made of the same Cu as the metal particles 44. In the heat dissipation process, an exothermic reaction represented by the chemical reaction formula (3) proceeds, and in the heat storage process, an endothermic reaction represented by the chemical reaction formula (4) proceeds.
CaO (s) + H ₂ O (g) → Ca (OH) ₂ (s) + Q (exotherm) (3)
Ca (OH) ₂ (s) → CaO (s) + H ₂ O (g) −Q (endothermic) (4)
FIG. 5 shows a configuration near the flat tube wall of the heat storage device in the present embodiment. Fig.5 (a) is a typical expanded sectional view of the flat tube tube wall vicinity, FIG.5 (b) is a graph which shows the relationship between the distance from the outer wall surface of a flat tube, and the density | concentration of a metal particle. . As shown in FIGS. 5A and 5B, when the distance from the outer wall surface 30c of the flat tube 30 in the packed bed 40 is X, the concentration of the metal particles 44 in the packed bed 40 increases as the distance X increases. It is low. That is, the concentration of the metal particles 44 in the packed bed 40 is high in the vicinity of the outer wall surface 30c, and the metal particles 44 become closer to the internal flow passages 41 and 42 (not shown in FIG. 5) away from the outer wall surface 30c. The concentration of is low. The concentration of the metal particles 44 may continuously decrease monotonously as the distance X increases as shown by the solid line in FIG. 5B, or the distance as shown by the broken line in FIG. 5B. As X increases, it may decrease stepwise.

  In the present embodiment, the concentration of the metal particles 44 in the packed bed 40 can be increased as the distance from the outer wall surface 30 c of the flat tube 30 is closer. Therefore, it is possible to reliably join the filling layer 40 and the outer wall surface 30c by sintering while securing the amount of the heat storage agent particles 43 as the whole filling layer 40, and between the filling layer 40 and the flat tube 30. The heat transfer resistance can be further reduced.

  By the way, in the vicinity of the internal flow passages 41 and 42, the reaction medium supplied from the outside in the heat dissipation process reaches earlier than the other regions, so that the exothermic reaction can proceed earlier. When an exothermic reaction is started in a part of the packed bed 40, the reaction heat is transmitted to promote the exothermic reaction in the surrounding heat storage agent particles 43. Therefore, in order to increase the reaction rate of the entire packed bed 40, it is effective to reduce the concentration of the metal particles 44 that do not contribute to the reaction in the vicinity of the internal flow passages 41 and 42 where the exothermic reaction can proceed early. . In the present embodiment, the concentration of the metal particles 44 in the packed bed 40 can be reduced in the vicinity of the internal flow passages 41 and 42 away from the outer wall surface 30c, so that the reaction rate of the packed bed 40 as a whole can be further increased. it can.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 6 shows a configuration near the flat tube wall of the heat storage device in the present embodiment. As shown in FIG. 6, the present embodiment is characterized in that the aspect ratio of the metal particles 44a, 44b, 44c in the packed bed 40 varies stepwise depending on the distance from the outer wall surface 30c. The first layer 40a adjacent to the outer wall surface 30c in the filling layer 40 is filled with, for example, spherical metal particles 44a having a relatively small aspect ratio. The second layer 40b, which is farther from the outer wall surface 30c than the first layer 40a, is filled with, for example, cylindrical metal particles 44b having a larger aspect ratio than the metal particles 44a. The third layer 40c further away from the outer wall surface 30c than the second layer 40b is filled with, for example, rod-shaped metal particles 44c having a larger aspect ratio than the metal particles 44b.

  As the aspect ratio of the filled metal particles 44a, 44b, and 44c increases, the void between the particles can be made larger. Therefore, the porosity of the first layer 40a is relatively low, and the porosity of the second layer 40b is the first. It becomes higher than the 1st layer 40a, and the porosity of the 3rd layer 40c becomes still higher than the 2nd layer 40b. That is, in the present embodiment, the porosity of the packed bed 40 can be increased as the distance from the outer wall surface 30c approaches the internal flow passages 41 and 42 (not shown in FIG. 6). Accordingly, the movement resistance when the reaction medium permeates into the packed bed 40 from the internal flow passages 41 and 42 can be lowered toward the internal flow passages 41 and 42 where the flow rate of the reaction medium is large. The outer wall surface 30c side where the flow rate is reduced can be increased. Therefore, according to this embodiment, since the reaction medium can be effectively diffused throughout the packed bed 40, the unreacted portion of the packed bed 40 can be reduced, and the thermal distribution inside the packed bed 40 can be relaxed. .

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 7 shows a configuration near the flat tube wall of the heat storage device in the present embodiment. As shown in FIG. 7, the present embodiment is characterized in that the particle diameters of the metal particles 44d, 44e, and 44f in the packed bed 40 differ stepwise depending on the distance from the outer wall surface 30c. The first layer 40a adjacent to the outer wall surface 30c in the packed layer 40 is filled with, for example, metal particles 44d having a spherical shape and a relatively small particle size. The second layer 40b, which is farther from the outer wall surface 30c than the first layer 40a, is filled with metal particles 44e having a particle diameter larger than that of the metal particles 44d. The third layer 40c that is further away from the outer wall surface 30c than the second layer 40b is filled with metal particles 44f having a larger particle diameter than the metal particles 44e. The distance between the centers of adjacent metal particles (interparticle distance) is relatively small in the first layer 40a, larger in the second layer 40b than the first layer 40a, and larger in the third layer 40c than in the second layer 40b. It is getting bigger.

  The larger the particle diameter and inter-particle distance of the metal particles 44d, 44e, and 44f to be filled, the larger the voids between the particles. Therefore, the porosity of the first layer 40a is relatively low, and the second layer 40b The porosity is higher than that of the first layer 40a, and the porosity of the third layer 40c is higher than that of the second layer 40b. That is, in the present embodiment, as in the third embodiment, the void ratio can be increased as the distance from the outer wall surface 30c and the closer to the internal flow passages 41 and 42 increases. Therefore, according to the present embodiment, as in the third embodiment, the unreacted portion of the filling layer 40 can be reduced, and the thermal distribution inside the filling layer 40 can be relaxed.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described with reference to FIG. FIG. 8 shows a configuration near the flat tube wall of the heat storage device in the present embodiment. As shown in FIG. 8, the present embodiment is characterized in that the particle diameters of the heat storage agent particles 43a, 43b, 43c in the packed bed 40 differ stepwise depending on the distance from the outer wall surface 30c. In the packed layer 40, the first layer 40a adjacent to the outer wall surface 30c is filled with heat storage agent particles 43a having a relatively small particle size. In the second layer 40b, which is farther from the outer wall surface 30c than the first layer 40a, the heat storage agent particles 43b having a particle diameter larger than that of the heat storage agent particles 43a are filled. The third layer 40c further away from the outer wall surface 30c than the second layer 40b is filled with the heat storage agent particles 43c having a particle diameter larger than that of the heat storage agent particles 43b.

  The larger the particle diameter of the heat storage agent particles 43a, 43b, and 43c to be filled, the larger the voids between the particles, so the porosity of the first layer 40a is relatively low, and the porosity of the second layer 40b is It becomes higher than the 1st layer 40a, and the porosity of the 3rd layer 40c becomes still higher than the 2nd layer 40b. That is, in the present embodiment, as in the third embodiment, the void ratio can be increased as the distance from the outer wall surface 30c and the closer to the internal flow passages 41 and 42 increases. Therefore, according to the present embodiment, as in the third embodiment, the unreacted portion of the filling layer 40 can be reduced, and the thermal distribution inside the filling layer 40 can be relaxed.

(Other embodiments)
In the above embodiment, the internal flow passages 41 and 42 whose ends are opposed to each other are taken as an example, but the internal flow passages 41 and 42 may be formed so as to penetrate from one to the other. In this case, the internal flow passages 41 and 42 constitute a through hole confined at the center of each of the internal flow passages 41 and 42.

  Moreover, in the said embodiment, although the metal particles 44 or the metal particles 44 and the outer wall surface 30c of the flat tube 30 were couple | bonded by sintering, the metal particles 44 or the metal particles 44 and the outer wall surface 30c were mentioned. The gaps may be bonded together.

  Furthermore, in the said embodiment, although Cu was mentioned as an example as a constituent material of the flat tube 30 and the metal particle 44, other metals, such as SUS, Fe, Al, can also be used as these constituent materials.

  Moreover, in the said embodiment, although CaO was mentioned as an example as a constituent material of the thermal storage agent particle | grains 43, other metal oxides, such as MgO and BaO, can also be used as a constituent material.

Further in the above embodiment, the heat storage agent is exemplified of H _{2 O} as a gas to the reaction medium, it is also possible to use other gases such as CO _2.

  Moreover, in the said embodiment, although the packed bed 40 with which the thermal storage agent particle 43 and the metal particle 44 were filled was mentioned as an example, the metallic particle 44 is not mixed but only the thermal storage agent particle 43 is filled, and the packed bed 40 is used. It may be formed.

DESCRIPTION OF SYMBOLS 1 Thermal storage apparatus 10 Outer case 20 Thermal storage core 23 Core part 30, 30a, 30b Flat tube (heat exchange part)
30c Outer wall surface (first heat exchange surface)
30d Inner wall surface (second heat exchange surface)
31 Fluid flow path 40 Packed layers 41, 42 Internal flow path 43 Thermal storage agent particles 44 Metal particles 45 Metal fibers

Claims (6)

A packed bed (40) filled with heat storage agent particles (43) composed of a metal oxide capable of reacting reversibly with the reaction medium using a gas as a reaction medium;
The reaction medium formed from the surface of the packed bed (40) toward the inside of the packed bed (40) and supplied from the outside is introduced into the packed bed (40), and the packed bed (40) An internal flow passage (41, 42) for discharging the reaction medium led out from the inside to the outside;
A fluid flow path (31) that is spatially isolated from the packed bed (40) and the internal flow passages (41, 42) and circulates a heat exchange fluid;
A first heat exchange surface (30c) that exchanges heat with the packed bed (40); and a second heat exchange surface (30d) that exchanges heat with the heat exchange fluid. A heat exchange part (30) for transferring heat between the packed bed (40) and the heat exchange fluid via heat exchange surfaces (30c, 30d);
The said internal flow path (41, 42) is formed so that it may become narrow gradually toward the back from the surface of the said packed bed (40), The heat storage apparatus characterized by the above-mentioned.   The packed bed (40) is sintered and bonded to the first heat exchange surface (30c), and the metal particles (44) or metal fibers (43) holding the heat storage agent particles (43). 45) The heat storage device according to claim 1, further comprising 45).   The packed bed (40) has a weight of the metal particles (44) or the metal fibers (45) with respect to the weight of the heat storage agent particles (43) as the distance from the first heat exchange surface (30c) increases. It is comprised so that a ratio may become lower, The heat storage apparatus of Claim 2 characterized by the above-mentioned.   The packed bed (40) is configured such that the aspect ratio of the metal particles (44) increases as the distance from the first heat exchange surface (30c) increases. The heat storage device according to 2 or 3.   The said packed bed (40) is comprised so that the interparticle distance of the said metal particle (44) may become large, so that the distance from the said 1st heat exchange surface (30c) becomes far. Item 4. A heat storage device according to item 2 or 3.   The said packed bed (40) is comprised so that the particle diameter of the said thermal storage agent particle | grain (43) may become larger, so that the distance from the said 1st heat exchange surface (30c) becomes far. Item 6. The heat storage device according to any one of Items 1 to 5.

Images