Integrated composite heat and cold storage device

Abstract

The invention belongs to the technical field of phase change heat storage, and discloses an integrated composite heat storage and cold storage device which comprises a box body, a plurality of phase change units, a connecting pipeline and a liquid distributing and collecting device. The box body is filled with water, and the phase change units are connected in series through pipelines. A phase change material filling cavity is formed in the phase change unit, and a heat exchange fluid flow channel is formed between the inner wall of the phase change unit and the outer wall of the phase change material filling cavity; the heat exchange fluid exchanges heat with water and the phase change material in the phase change unit at the same time. The problems that in the prior art, the heat storage density is low, and only heat storage or cold storage can be achieved are solved. The energy storage device has the advantages that energy storage work is jointly completed through two media, the energy storage device can be applied to double working scenes of heat storage and cold storage, and the equipment cost and the occupied space are reduced; in heat storage and cold storage scenes, the phase change process of the medium is involved, and the high energy storage density is achieved; the device comprises a plurality of phase change units, the appropriate number of the units can be selected according to different applications, and the application scene is flexible.

Description

Technical Field

[0001] The invention belongs to the technical field of phase change heat storage, and relates to an integrated composite heat storage and cold storage device. Background Art

[0002] Electricity utilization varies with time periods. During peak electricity consumption periods, in order to ensure electricity supply, it is necessary to strengthen grid construction and ensure transmission and distribution capabilities in the transmission and distribution links. In the power generation link, it is necessary to mobilize high-cost generators to generate electricity at peak times. Therefore, the power supply cost during peak electricity consumption periods is higher than that during off-peak periods.

[0003] Energy storage technology achieves "valley filling and peak shifting" by storing energy during the off-peak period of electricity consumption and releasing the stored energy during the peak period of electricity consumption. Heat storage methods are mainly divided into three categories: sensible heat storage, latent heat storage and chemical energy storage, which can meet different energy storage duration requirements (short-term energy storage and long-term energy storage across seasons) and temperature requirements. Among them, sensible heat storage and latent heat storage are the current mainstream heat storage methods. Water, as a medium that can store both heat and cold, is often used in low-temperature applications (<120℃). Since water undergoes phase change when used for cold storage, latent heat storage is performed. Therefore, when water is used as a cold storage medium, the device will have a higher cold storage density; when it is used for heat storage, sensible heat storage is performed, and its heat storage density is lower. Phase change materials store heat and cold in the form of latent heat, have a higher energy density, and are widely used in single heat storage or single cold storage. Therefore, water has a greater advantage in cold storage applications, while phase change materials have a greater advantage in heat storage applications.

[0004] In recent years, with the rapid development of my country's economy and the improvement of people's living standards, the demand for heating in areas with hot summers and cold winters has increased. Therefore, in addition to the demand for cooling in summer, there is also a demand for heating in winter in areas with hot summers and cold winters in my country; accordingly, when using heat storage heating technology, it is also necessary to consider the use of heat storage equipment. At present, some devices for heat storage or cold storage have been announced, such as: a composite phase change heat storage device (patent application number 202410043890.8), a finned tube phase change heat storage device (patent application number 202311401519.6), a multi-ribbed ice cold storage tube and ice cold storage tank (patent application number 202410146574.3), etc. These energy storage devices or methods can only achieve the purpose of only heat storage or only cold storage, and additional heat storage or cold storage devices greatly increase the cost and occupy space.

[0005] In summary, the present invention combines the advantages of water and phase change materials, and proposes an energy storage device that can be used for both heat storage and cold storage, reducing equipment costs and occupied space. In addition, when storing heat or cold, the phase change process of the energy storage medium is involved, and latent heat energy storage is performed, which has a high energy storage density; the device includes a number of phase change units, and the appropriate number of units can be selected according to different applications, and the application scenarios are flexible. Summary of the invention

[0006] The purpose of the present invention is to provide an integrated composite heat storage and cold storage device to solve the problem that the energy density is low when using a water tank for heat storage, and the current same energy storage device can only perform single heat storage or single cold storage scenarios.

[0007] On the basis of the traditional hot water storage tank, the present invention combines sensible heat storage and phase change storage, and adds phase change materials to increase the heat storage density and efficiency of the water tank. At the same time, when storing cold, the main energy storage medium (water) stores energy in the form of latent heat, which also has a high cold storage density. The device of the present invention can be used for both heat storage and cold storage, and has a high energy storage density in both energy storage operations.

[0008] The technical solution of the present invention:

[0009] An integrated composite heat storage and cold storage device comprises a water tank, an insulation layer, a phase change unit, a connecting pipe, a liquid separator and a liquid collector; a phase change material filling cavity is arranged inside the phase change unit, and the phase change material filling cavity is filled with phase change material; the phase change material filling cavity is fixed in the phase change unit through a supporting member; the connecting pipe connects the phase change units in series and is placed in the water tank as a whole; the liquid separator is connected to the upper connecting pipe, and the liquid separator is connected to the heat exchange fluid inlet; the liquid collector is connected to the lower connecting pipe, and the liquid collector is connected to the heat exchange fluid outlet; when storing heat or cold, the water tank is filled with water; the heat exchange fluid enters the liquid separator from the heat exchange fluid inlet, is separated by the liquid separator, flows through the connecting pipe and the phase change unit, finally enters the liquid collector, and leaves from the heat exchange fluid outlet; when flowing through the connecting pipe, the heat exchange fluid exchanges heat with the water in the water tank; when flowing through the phase change unit, the heat exchange fluid simultaneously exchanges heat with the water in the water tank and the phase change material in the phase change unit.

[0010] Furthermore, the shape of the water tank includes but is not limited to a cube or a cylinder.

[0011] Furthermore, a heat-insulating layer is laid on the outside of the water tank, and a heat-exchange fluid inlet and a heat-exchange fluid outlet are provided.

[0012] Furthermore, a fixed frame is provided inside the water tank to fix the phase change unit and the connecting pipe.

[0013] Furthermore, the phase change unit includes an outer shell, a supporting member, a phase change material filling cavity and end caps at both ends; the end caps are welded to fix the outer shell and the phase change material filling cavity, and the two ends of the phase change material filling cavity are welded to the end caps, and the end caps play a sealing role; the phase change material filling cavity is horizontally arranged in the phase change unit through the supporting member; a heat exchange fluid flow channel is formed between the inner wall of the phase change unit and the outer wall of the phase change material filling cavity; when the device is storing heat or cold, the heat exchange fluid enters the phase change unit through the connecting pipe, and when flowing through the heat exchange fluid flow channel, it simultaneously exchanges heat with the energy storage medium inside and outside the phase change unit.

[0014] Furthermore, the shape of the phase change unit includes but is not limited to a cylinder.

[0015] Furthermore, the phase change material filling cavity is arranged inside the phase change unit through a supporting member, and the two are coaxial.

[0016] Furthermore, the support member is welded on the outer wall of the phase change material filled cavity, and its shape includes but is not limited to semicircular and circular, and the shape of the through hole on its cross section includes but is not limited to fan-shaped.

[0017] Furthermore, fins are arranged inside the phase change material filling cavity.

[0018] Beneficial effects of the present invention:

[0019] 1. The present invention can be used in both heat storage and cold storage scenarios, reducing equipment costs and occupied space.

[0020] 2. When storing heat or cold, the heat exchange fluid exchanges heat with two energy storage media (water in the water tank and phase change material in the phase change unit). Both heat and cold storage scenarios involve the phase change process of the energy storage medium, which has a higher energy storage density.

[0021] 3. When storing heat, the heat exchange fluid flows through the heat storage unit and the channel, while releasing heat to the phase change material and the water in the water tank. The phase change material absorbs heat and undergoes phase change, and the water in the water tank absorbs heat and the temperature rises. In this process, the phase change material performs latent heat storage and is the main heat storage medium; water performs sensible heat storage and is an auxiliary heat storage medium. When storing cold, the water in the water tank becomes the main cold storage medium. When the heat exchange medium flows through the heat storage unit and the channel, the water releases heat and undergoes phase change, and freezes on the outer wall of the channel and the phase change unit; at the same time, the heat exchange fluid also absorbs the heat of the phase change material, that is, the phase change material, as an auxiliary cold storage medium, will also bear part of the cold storage capacity.

[0022] The device includes several phase change units, and the appropriate number of units can be selected according to different applications, and the application scenarios are flexible. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1Schematic diagram of the internal structure of the water tank of the device of the present invention.

[0024] Figure 2 It is a partial cross-sectional view of the device of the present invention.

[0025] Figure 3 It is a top view of the device of the present invention.

[0026] Figure 4 Schematic diagram of the phase change unit of the device of the present invention.

[0027] Figure 5 Schematic diagram of the internal structure of the phase change unit of the device of the present invention.

[0028] Figure 6 It is a schematic diagram of the phase change material filling cavity and the fixing components of the device of the present invention.

[0029] Figure 7 It is a main cross-sectional view of the phase change unit of the device of the present invention.

[0030] Figure 8 2 is a cross-sectional view aa of the phase change unit of the device of the present invention.

[0031] In the figure: 1. phase change unit; 2. connecting pipe; 3. heat exchange fluid inlet; 4. liquid distributor; 5. heat exchange fluid outlet; 6. liquid collector; 7. water tank wall; 8. insulation layer; 9. fixed frame; 10. phase change material filling cavity; 11. ribs; 12. supporting member; 13. head; 14. shell; 15. outer wall of phase change material filling cavity; 16. phase change material; 17. heat exchange fluid flow channel. DETAILED DESCRIPTION

[0032] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and technical solutions.

[0033] like Figure 1 , Figure 2 and Figure 3 As shown, the present invention provides an integrated composite heat storage and cold storage device, which has a similar structure to an ice storage coil, including a phase change unit 1, a water tank and an insulation layer 8, a connecting pipe 2, a liquid distributor 4 and a liquid collector 6; the phase change units 1 are evenly distributed in the water tank 7, and the phase change units 1 are connected in series through the connecting pipe 2; the phase change units 1 and the connecting pipe 2 are fixed in the water tank through a fixing frame 9; an insulation layer 8 is laid on the outside of the water tank; the water tank 7 is a square water tank, and the insulation layer 8 is made of quartz wool felt.

[0034] like Figure 4 As shown, in this embodiment, the phase change unit 1 is cylindrical in shape, with both ends connected to the pipe 2. Figure 5As shown, the phase change unit 1 includes a housing 14, a phase change material filling cavity 10, a support member 12 and a head 13. The connecting pipe 2 is welded to the phase change unit 1; the phase change material filling cavity 10 is filled with a phase change material 16 and provided with fins 11, and the phase change material 16 is sodium acetate trihydrate. Figure 6 As shown, the phase change material filling cavity 10 is welded with the end cap 13. To prevent the phase change material filling cavity 10 from being too long and bending, a support member 12 is required. In this embodiment, a semicircular support member is used, and a fan-shaped through hole is used on the member, such as Figure 8 The installation process of the phase change unit 1 is as follows: first, a suitable number of support members 12 are welded to the outer wall 15 of the phase change material filling cavity, then the phase change material filling cavity 10 is horizontally placed in the phase change unit 1, and finally, the head 13 is welded to the phase change material filling cavity 10 and the shell 14 to fix and seal the phase change material filling cavity 10 in the phase change unit 1.

[0035] like Figure 7 As shown, a heat exchange fluid flow channel 17 is formed between the outer wall 15 of the phase change material filling cavity and the inner wall of the phase change unit, and the heat exchange fluid will flow through the phase change unit 1 in the form of "up in and down out".

[0036] When storing energy, the heat exchange fluid first enters the liquid distributor 4 through the heat exchange fluid inlet 3 for diversion, and then flows through the connecting pipe 2 and the phase change unit 1 successively; in the connecting pipe 2, the heat exchange fluid exchanges heat with the water in the water tank; in the phase change unit 1, the heat exchange fluid exchanges heat with the water in the water tank and the phase change material 16 at the same time. After flowing through a corresponding number of phase change units 1, the heat exchange fluid enters the liquid collector 6 and flows out from the heat exchange fluid outlet 5. When storing heat, the heat exchange fluid uses water, the main heat storage medium is the phase change material 16 located in the phase change unit 1, and the water in the water tank is an auxiliary heat storage medium; when storing cold, the heat exchange fluid uses ethylene glycol, the main cold storage medium is the water in the water tank, and the phase change material 16 in the phase change unit 1 is an auxiliary cold storage medium.

Claims

1. An integrated composite heat storage and cold storage device, characterized in that: The integrated composite heat storage and cold storage device comprises a water tank, an insulation layer, a phase change unit, a connecting pipe, a liquid separator and a liquid collector; a phase change material filling cavity is arranged inside the phase change unit, and the phase change material is filled in the phase change material filling cavity; the phase change material filling cavity is fixed in the phase change unit through a supporting member; the connecting pipe connects the phase change units in series and is placed in the water tank as a whole; the liquid separator is connected to the upper connecting pipe, and the liquid separator is connected to the heat exchange fluid inlet; the liquid collector is connected to the lower connecting pipe, and the liquid collector is connected to the heat exchange fluid outlet; when storing heat or cold, the water tank is filled with water; the heat exchange fluid enters the liquid separator from the heat exchange fluid inlet, is separated by the liquid separator, flows through the connecting pipe and the phase change unit, finally enters the liquid collector, and leaves from the heat exchange fluid outlet; when flowing through the connecting pipe, the heat exchange fluid exchanges heat with the water in the water tank; when flowing through the phase change unit, the heat exchange fluid simultaneously exchanges heat with the water in the water tank and the phase change material in the phase change unit.

2. The integrated composite heat storage and cold storage device according to claim 1, characterized in that: The shape of the water tank includes but is not limited to a cube or a cylinder. A heat-insulating layer is laid on the outside of the water tank, and a heat-exchange fluid inlet and a heat-exchange fluid outlet are provided.

3. The integrated composite heat storage and cold storage device according to claim 1, characterized in that: A fixed frame is arranged inside the water tank to fix the phase change unit and the connecting pipe.

4. The integrated composite heat storage and cold storage device according to claim 1, characterized in that: The phase change unit includes an outer shell, a supporting member, a phase change material filling cavity and end caps at both ends; the end caps weld and fix the outer shell and the phase change material filling cavity, and the two ends of the phase change material filling cavity are welded to the end caps, and the end caps play a sealing role; the phase change material filling cavity is horizontally arranged in the phase change unit through the supporting member; a heat exchange fluid flow channel is formed between the inner wall of the phase change unit and the outer wall of the phase change material filling cavity; when the device is storing heat or storing cold, the heat exchange fluid enters the phase change unit through the connecting pipe, and when flowing through the heat exchange fluid flow channel, it simultaneously exchanges heat with the energy storage medium inside and outside the phase change unit.

5. The integrated composite heat storage and cold storage device according to claim 1, characterized in that: The shape of the phase change unit includes but is not limited to a cylinder.

6. The integrated composite heat storage and cold storage device according to claim 1, characterized in that: The phase change material filling cavity is arranged inside the phase change unit through a supporting member, and the two are coaxial.

7. The integrated composite heat and cold storage device according to claim 1, characterized in that: The support member is welded on the outer wall of the phase change material filled cavity, and its shape includes but is not limited to semicircular and circular, and the shape of the through hole on its cross section includes but is not limited to fan-shaped.

8. The integrated composite heat and cold storage device according to claim 1, characterized in that: The phase change material filling cavity is provided with fins inside.

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