CN111473673B

CN111473673B - Single-tank packed bed heat storage device with bionic choroid structure and arranged according to generalized Murrill's law and using method thereof

Info

Publication number: CN111473673B
Application number: CN202010305171.0A
Authority: CN
Inventors: 王富强; 东岩
Original assignee: Harbin Institute of Technology Weihai
Current assignee: Harbin Institute of Technology Weihai
Priority date: 2020-04-17
Filing date: 2020-04-17
Publication date: 2021-07-30
Anticipated expiration: 2040-04-17
Also published as: CN111473673A

Abstract

A single-tank packed bed heat storage device with a bionic venation structure and arranged according to the generalized Murrill's law and a using method thereof belong to the field of energy storage. The problems of low heat storage density, small heat exchange area and uneven heat storage speed in the traditional heat storage system with the packed bed are solved. The key points are as follows: the heat storage device comprises a storage tank, a support is arranged in the storage tank in a bionic vein structure mode, heat storage balls with different diameters are arranged in the storage tank according to the generalized Ruili law, and the support is used for supporting the heat storage balls and preventing the heat storage balls from floating randomly. The use method realizes heat storage, heat release and heat storage through the heat storage ball which is arranged according to the generalized Murrill's law and has the bionic venation structure. According to the invention, by changing the arrangement mode and size of the heat storage balls in the storage tank, the heat storage system realizes higher heat storage efficiency, higher heat storage density and faster thermal response capability compared with the traditional system, and the bionic venation structure is a high-efficiency nutrient transport system selected naturally and has unique advantages in the aspects of material transport and energy transfer.

Description

Single-tank packed bed heat storage device with bionic choroid structure and arranged according to generalized Murrill's law and using method thereof

Technical Field

The invention relates to a single-tank packed bed heat storage device, in particular to a single-tank packed bed heat storage device which is arranged according to the generalized Murrill's law and has a bionic venation structure and a using method thereof, and belongs to the technical field of energy storage.

Background

There is an increasing research on solar energy, but due to the periodicity of solar radiation, the energy obtained needs to be temporarily stored. At present, the heat storage is mainly stored through a heat storage tank, and common heat storage modes are divided into a double-tank heat storage system and a single-tank heat storage system. Wherein, commercial heat storage tank usually adopts two jar heat-retaining systems, and this system comprises cold and hot two jars but this system cost is high and takes up an area of big. The single-tank heat storage system is also called as thermocline heat storage, the heat storage and release processes of the system are all carried out through one storage tank, and the system has the advantages of simple structure and small occupied area. Meanwhile, the heat storage ball is added into the single tank, so that the heat storage density of the storage tank can be further improved, and the stable output temperature can be maintained. Therefore, the single-tank stacked-bed heat storage device is more and more widely applied to the field of solar energy storage.

The single-tank packed bed heat storage system is a common form of single-tank heat storage at present, and the arrangement mode is that a single-size heat storage unit is randomly filled in a storage tank. The main disadvantage of the arrangement mode is that the attenuation of the heat exchange temperature and the heat exchange rate of the vertical direction and the radial direction of the tank body in the heat exchange process is not considered. In the heat storage process, high-temperature fluid flows in from the upper inlet and exchanges heat with the internal heat storage unit, so that the temperature of the heat transfer fluid is gradually reduced. This change makes the heat storage unit at the lower part of the tank body unable to exchange heat with the same temperature difference as the upper unit, resulting in a reduction in heat storage efficiency. Meanwhile, heat exchange fluid enters from the upper inlet, so that even though the flow equalizing effect is achieved under the action of the guide plate, the phenomenon that the radial distribution of the fluid in the tank is uneven cannot be completely avoided, and the heat storage efficiency of the heat storage unit on the near-wall side of the storage tank can be reduced due to the phenomenon. In addition, the accumulation bed formed by the currently adopted single-diameter heat accumulation units has larger accumulation gaps and lower heat accumulation density. The foregoing are all inherent disadvantages of the current single-tank packed bed thermal storage systems and need to be improved.

Disclosure of Invention

The invention aims to solve the problems of low heat storage density, small heat exchange area and uneven heat storage speed in a traditional heat storage system of a packed bed, and further provides a single-tank heat storage device with a bionic venation structure and a using method thereof, wherein the heat storage device is arranged according to the generalized Runli law. The brand new heat storage unit arrangement structure designed by the invention improves the heat storage efficiency and the heat storage density of the heat storage system, reduces the response time of the system and has wide application space.

In order to achieve the purpose, the invention adopts the following technical scheme:

the first scheme is as follows: the utility model provides a follow single jar of bed heat-retaining device that piles up that bionical choroid structure has that general morly law arranged, includes the storage tank, is provided with the support with bionical choroid structural style in the storage tank, and the heat-retaining ball that has different diameters follows general morly law and arranges in the storage tank, and the support is used for supporting the heat-retaining ball and prevents it to float at will.

Further: the generalized law of murray is defined as:

wherein r is₀Is the radius of the mother passage, r_iIs the subchannel radius; x is the mass change rate in the transmission process, and if the transmission process is a pure physical process, X is 0; a varies according to the type of the transfer medium, and a takes 3 when relating to fluid and alpha takes 2 when relating to mass diffusion and ion diffusion, and the channel refers to a flow channel of the heat transfer fluid formed between the bracket and the heat storage ball.

Further: and the upper end and the lower end of the storage tank are additionally provided with a circular truncated cone-shaped auxiliary storage tank through flanges. The two circular truncated cone-shaped auxiliary storage tanks can guide the heat transfer fluid flowing through to a certain extent.

Further: the top and the bottom of storage tank are installed the shunt, are the pile up bed that the heat-retaining ball constitutes between two shunts. The two flow diverters are capable of diverting to some extent the heat transfer fluid flowing therethrough.

Further: the fluid inlet pipeline of the storage tank is a fluid inlet pipeline when being heated and is a fluid outlet pipeline when being heated. The fluid outlet pipeline of the storage tank is a fluid outlet pipeline when being heated and is a fluid inlet pipeline when being heated

Further: the bionic venation structure is specifically as follows: the accumulation bed is accumulated from top to bottom and from the axis to the wall surface by adopting an approximate large-medium-small-micro bionic venation structure, the arrangement mode follows the generalized Murrill law, and the heat transfer fluid flows in the accumulation bed in a multi-stage venation bifurcation structure approximate to trunk-branch-tail end. Such as the veins of the leaves.

Further: the support is a metal support. Has high pressure resistance and heat resistance. The metal support is designed according to the generalized Ruili's law and is arranged in the storage tank in an approximate vein form for supporting the piled up heat storage balls and preventing the balls from floating freely.

Further: the heat storage balls with different diameters can be filled with different heat storage materials according to requirements, and the heat storage materials include but are not limited to phase change materials and molten salt materials. Meanwhile, the diameter of the heat storage ball can be designed according to actual requirements and the accumulation mode can be changed.

Further: the heat transfer fluid may be either a gas or a liquid.

Scheme II: the application method of the single-tank packed bed heat storage device with the bionic choroid structure, which is arranged according to the generalized Murrill's law, is realized on the basis of a first scheme. The method specifically comprises the following steps:

the using process comprises three processes of heat storage, heat release and heat storage, and specifically comprises the following steps:

during heat storage, high-temperature heat transfer fluid flows into the region where the accumulation bed is located from an inlet at the top of the storage tank and flows in the radial direction and the axial direction, heat storage balls with large diameters in the main region of the bionic vein structure of the accumulation bed absorb heat of the heat transfer fluid with low flow speed and store the heat, meanwhile, the heat transfer fluid flows in the accumulation bed in a bionic vein conveying mode, the temperature of the heat transfer fluid is reduced after flowing through the main region of the bionic vein structure and exchanges heat with heat storage balls with small diameters in the branch regions of the bionic vein structure, the heat storage balls with small diameters have large heat exchange areas, the heat transfer efficiency is improved, and low-temperature fluid after complete heat exchange flows out from an outlet at the; when the outlet temperature rises to a certain set temperature, the heat storage process of the storage tank is determined to be finished;

when heat is stored, the inlet and the outlet of the storage tank are closed, and heat is stored by means of the heat storage ball and the heat storage fluid in the storage tank;

when releasing heat, low-temperature heat transfer fluid flows in from the inlet at the bottom of the storage tank, flows in the stacking bed along the radial direction and the axial direction in a bionic vein structure conveying mode, the high-temperature heat storage ball releases heat to the heat transfer fluid under the action of temperature difference, the heat transfer fluid with the increased temperature flows in the branch region of the bionic vein structure, the heat exchange process under the low heat transfer temperature difference is carried out with a larger heat transfer area, the high-temperature fluid after complete heat exchange flows out from the outlet at the top of the storage tank, along with the heat release process, the heat of the heat storage ball in the storage tank is continuously released, and the heat storage process of the storage tank is determined to be finished after the outlet temperature is reduced to a certain set temperature.

The invention achieves the following effects:

1. the bionic venation structure used by the invention is designed according to the generalized Ruili law, so that the heat transfer fluid conveying channel and the heat storage balls can be arranged according to the optimal structure, and stronger theoretical background support is provided.

2. According to the invention, heat storage units with different sizes are arranged according to the vein structure according to the vein forming principle. This arrangement enables fluid flow in a manner approximating choroidal transport. The high-temperature fluid exchanges heat with the larger heat storage balls, and the fluid with relatively low temperature exchanges heat with the small-diameter heat storage balls with larger heat transfer areas, so that the temperature delay in the heat storage and release process is reduced, and the heat exchange efficiency of the storage tank system is improved.

3. The small-diameter heat storage ball related by the invention can be filled in the stacking gap of the large-diameter heat storage ball, so that the heat storage density of the storage tank system is increased. The heat storage unit size decreases regularly in multiple directions and, finally, ends with a fixed small size. Make holistic heat transfer area maximize through further branch and packing, strengthen device convection current heat transfer effect for temperature distribution is more even in the storage tank.

4. The metal support adopted by the invention can ensure that the heat penetrating fluid maintains the flow uniformity and avoid the secondary mixing of cold and hot fluids. Meanwhile, the metal support can play a role in fixing, and the heat storage balls with different diameters are prevented from moving randomly in actual operation.

5. In actual use, the specification of the heat storage ball can be independently designed according to actual operation conditions, so that the whole system is more flexible and efficient.

Drawings

FIG. 1 is a schematic axial view of a conical biomimetic choroid heat storage device of the present invention;

FIG. 2 is a schematic view of the radial structure of the conical biomimetic choroid heat storage device of the present invention;

FIG. 3 is a schematic view of a bracket of the conical biomimetic choroid heat storage apparatus of the present invention;

FIG. 4 is a schematic axial view of a diamond-shaped biomimetic choroid heat storage device according to the present invention;

FIG. 5 is a schematic radial structure diagram of a diamond-shaped bionic choroid heat storage device of the present invention;

FIG. 6 is a schematic view of a bracket of the diamond-shaped biomimetic choroid heat storage apparatus of the present invention;

FIG. 7 is a schematic axial view of an umbrella-shaped biomimetic choroid heat storage device according to the present invention;

FIG. 8 is a schematic radial structure diagram of an umbrella-shaped bionic choroid heat storage device of the present invention;

fig. 9 is a schematic view of a bracket of the umbrella-shaped bionic choroid heat storage device of the present invention.

In the figure, 1-cylindrical main tank; 2-an upper end circular truncated cone-shaped auxiliary storage tank; 3-a lower end circular truncated cone-shaped auxiliary storage tank; 4-a heat transfer fluid inlet; 5-a heat transfer fluid outlet; 6-upper connecting flange; 7-lower connecting flange; 8-an upper deflector; 9-a lower deflector; 10-large diameter heat storage ball; 11-medium diameter heat storage balls; 12-small diameter heat storage balls; 13-micro diameter heat storage balls; 14-a backbone metal scaffold; 15-metal branch stent; 16-terminal metal stent.

Detailed Description

Preferred embodiments of the present invention are explained in detail below with reference to the accompanying drawings.

Example 1: as shown in fig. 1 to fig. 3, the single-tank stacked-bed heat storage device with a bionic venation structure, which is arranged according to the generalized morley law, according to the present embodiment is composed of a stacked-bed heat storage tank, a heat storage ball, and an inlet/outlet pipe section: the accumulation bed heat storage tank comprises a cylindrical main storage tank 1, an upper-end round table-shaped auxiliary storage tank 2 and a lower-end round table-shaped auxiliary storage tank 3, wherein the auxiliary storage tank 2 is connected with the main storage tank 1 through a flange 6, the auxiliary storage tank 3 is connected with the main storage tank 1 through a flange 7, the upper-portion auxiliary storage tank 2 is connected with a heat transfer fluid inlet 4, and the upper-portion auxiliary storage tank 3 is connected with a heat transfer fluid inlet 5; the top and the bottom of the cylindrical heat storage tank 1 are respectively provided with guide plates 8 and 9, a stacked bed consisting of heat storage balls is arranged between the two guide plates, and a gap between the two guide plates is used as a heat transfer medium flow channel; the packed bed is arranged in a bionic vein form in the axial direction and is positioned by a main metal bracket 14, a branch metal bracket 15 and a tail end metal bracket 16 which are of vein hierarchies.

The accumulation bed is regularly reduced in the radial direction according to the generalized Murrill law, a large-medium-small-micro bionic venation structure is filled from the center to the wall surface, the heat storage unit comprises a large-size heat storage ball 10, a medium-size heat storage ball 11, a small-size heat storage ball 12 and a micro-size heat storage ball 13, and the heat storage balls are positioned by a main metal support 14, a branch metal support 15 and a tail end metal support 16 which are of venation hierarchical structures.

The metal stent is designed in a multi-level venation bifurcation structure which is similar to a trunk-branch-end structure according to the generalized Murrill's law, and the multi-level venation bifurcation structure comprises a trunk metal stent 14, a branch metal stent 15 and an end metal stent 16. The design mode can play a certain flow guide role in heat transfer fluid while fixing the heat storage ball.

The heat exchange process of the single-tank packed bed heat storage device with the bionic choroid structure, which is arranged according to the generalized Murrill law, is as follows: high temperature heat transfer fluid enters from an inlet 4 at the upper part of the storage tank, flows into the area where the packed bed is located through a guide plate 8 and flows along the radial direction and the axial direction. Heat exchange is firstly carried out with the

heat storage balls

10 and 11 with larger diameters, and heat exchange is carried out with the

heat storage balls

12 and 13 with smaller diameters after the temperature is reduced. The cryogenic fluid after heat exchange flows out from the outlet 5 through the lower guide plate 9. And when the outlet temperature rises to a certain set temperature, the heat storage process of the tank body is considered to be finished.

The principle of the stacked bed arrangement of the single-tank stacked bed heat storage device with the bionic venation structure, which is arranged according to the generalized Murrill's law, is as follows: the heat transfer fluid flows into the storage tank from the upper inlet and then flows along the flow channel formed by the accumulation of the heat storage balls and exchanges heat with the heat storage balls under the action of temperature difference, and the flow form of the heat transfer fluid is similar to the main transportation of a vein structure. For the whole device, the heat exchange temperature difference is continuously reduced along with the increase of the retention time of the fluid in the storage tank, and the heat storage efficiency of the heat storage ball is reduced. Therefore, the heat exchange area needs to be increased by adopting the small-diameter heat storage balls for accumulation, and the flow form at the moment is similar to the branch transportation of the vein structure. As heat exchange continues, the fluid temperature further decreases and heat exchange can therefore be performed by providing smaller phase change heat storage spheres with a flow pattern similar to the terminal transport of the vein structure. The heat storage balls with smaller diameters can fill gaps of the heat storage balls with large diameters while increasing heat transfer area, so that heat storage efficiency of the whole system is improved, and heat storage density is increased. The arrangement mode of the heat storage units is calculated according to the generalized Ruili law, and compared with the traditional single-diameter heat storage ball accumulation bed, the heat storage device provided by the invention can increase the heat exchange area of the system, improve the thermal response capacity and greatly improve the heat storage efficiency and the heat storage density of the system.

Example 2: as shown in fig. 4 to fig. 6, the single-tank packed bed heat storage device with a bionic choroid structure according to the generalized morley law in the present embodiment is different from that in example 1 in that the bionic choroid structure is a rhombic bionic choroid structure.

Example 3: as shown in fig. 7 to 9, the single-tank packed bed heat storage device having a bionic choroid structure according to the generalized morley law in the present embodiment is different from that in example 1 or 2 in the bionic choroid structure, which is an umbrella-shaped bionic choroid structure.

In the single-tank packed bed heat storage device with a bionic choroid structure, which is arranged according to the generalized Ruili law in the embodiments 1-3, the arrangement mode and the size of the phase-change heat storage ball in the storage tank are changed, so that the heat storage system realizes higher heat storage efficiency, higher heat storage density and faster heat response capability compared with the traditional system. The bionic venation structure adopted by the arrangement structure is a naturally selected high-efficiency nutrient delivery system, and has unique advantages in the aspects of material delivery and energy transfer.

The above examples are only for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention. In particular, the above implementation shows only four layers of bionic vein structure, and the heat storage device with five layers and more or similar vein-shaped stacked beds has the same principle as the above implementation and should be included in the protection scope of the present invention.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. A single-tank packed bed heat storage device with a bionic venation structure and arranged according to the generalized Morie's law is characterized by comprising a storage tank, wherein a support is arranged in the storage tank in the form of the bionic venation structure, heat storage balls with different diameters are arranged in the storage tank according to the generalized Morie's law, and the support is used for supporting the heat storage balls and preventing the heat storage balls from floating randomly;

the top and the bottom of the storage tank are provided with shunts, and a stacking bed formed by heat storage balls is arranged between the two shunts;

the stent is designed in a multi-level venation bifurcation structure which is similar to a trunk, a branch and a tail end according to the generalized Murrill's law;

the bionic venation structure is specifically as follows: the stacked bed formed by the heat storage balls is stacked from top to bottom and from the axis to the wall surface by adopting an approximate large-medium-small-micro bionic venation structure, the arrangement mode follows the generalized Murrill law, and the heat transfer fluid flows in the stacked bed in a multi-stage venation branching structure approximate to a main body, branches and ends.

2. The single-tank packed bed heat storage device with a biomimetic choroid structure arranged according to the generalized Murrill's Law of claim 1, wherein: the generalized law of murray is defined as:

whereinr ₀Is the radius of the female channel,r _iis the subchannel radius;Xfor the rate of change of mass during the transfer process, if the transfer process is purely physicalXTaking 0; alpha varies according to the type of transfer medium, and takes 3 for fluid and 2 for mass diffusion and ion diffusion, and the channel refers to a flow channel of the heat transfer fluid formed between the bracket and the heat storage ball.

3. The single-tank packed bed heat storage device with a biomimetic choroid structure, arranged according to the generalized Murrill's Law, according to claim 1 or 2, wherein: and the upper end and the lower end of the storage tank are additionally provided with a circular truncated cone-shaped auxiliary storage tank through flanges.

4. The single-tank packed bed heat storage device with a biomimetic choroid structure, arranged according to the generalized Murrill's Law, according to claim 1 or 2, wherein: the support is a metal support.

5. The single-tank packed bed heat storage device with a biomimetic choroid structure arranged according to the generalized Murrill's Law of claim 1, wherein: the heat storage balls with different diameters can be filled with different heat storage materials according to requirements, including but not limited to phase change materials and molten salt materials, and meanwhile, the diameters of the heat storage balls can be designed according to actual requirements and the accumulation mode can be changed.

6. The single-tank packed bed heat storage device with a bionic choroid structure, according to the generalized Murrill's Law arrangement of claim 1 or 5, wherein: the heat transfer fluid is a gas or a liquid.

7. The use method of the single-tank stacked bed heat storage device with the bionic choroid structure, which is arranged according to the generalized Murrill's law, is realized on the basis of the heat storage device in the claim 1, and is characterized by comprising the following steps of:

during heat storage, high-temperature heat transfer fluid flows into the region where the accumulation bed is located from an inlet at the top of the storage tank and flows along the radial direction and the axial direction, heat storage balls with large diameters in the main region of the bionic vein structure of the accumulation bed absorb heat of the heat transfer fluid with low flow speed and store the heat, meanwhile, the heat transfer fluid flows in the accumulation bed in a bionic vein conveying mode, the temperature of the heat transfer fluid is reduced after flowing through the main region of the bionic vein structure and exchanges heat with the heat storage balls with small diameters in the branch regions of the bionic vein structure, and low-temperature fluid after complete heat exchange flows out from an outlet at the bottom of the storage tank; when the outlet temperature rises to a certain set temperature, the heat storage process of the storage tank is determined to be finished;