An integrated composite heat and cold storage device

Abstract

This invention belongs to the field of phase change thermal energy storage technology and discloses an integrated composite thermal and cold energy storage device, including a housing, several phase change units, connecting pipes, and liquid distributors and collectors. The housing is filled with water, and the phase change units are connected in series via pipes. Each phase change unit has a phase change material filling cavity, 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 simultaneously exchanges heat with both water and the phase change material within the phase change unit. This invention solves the problems of low thermal energy storage density and the inability to achieve only thermal or cold energy storage in existing technologies. The achieved technical effects are as follows: energy storage is completed by two media working together, enabling application in both thermal and cold energy storage scenarios, reducing equipment costs and space requirements; both thermal and cold energy storage scenarios involve phase change processes of the media, resulting in high energy storage density; the device includes several phase change units, allowing for flexible application scenarios by selecting the appropriate number of units according to different applications.

Description

Technical Field

[0001] This invention belongs to the field of phase change heat storage technology and relates to an integrated composite heat and cold storage device. Background Technology

[0002] Electricity utilization varies over time. During peak electricity consumption periods, in order to ensure power supply, it is necessary to strengthen the construction of the power grid and ensure the transmission and distribution capacity in the transmission and distribution links, and to mobilize high-cost generator units to generate electricity at peak times in the power generation links. Therefore, the cost of power supply 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 off-peak hours and releasing it during peak hours. Thermal energy 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 and long-term inter-seasonal storage) and temperature requirements. Among them, sensible heat storage and latent heat storage are currently the mainstream methods. Water, as a medium that can store both heat and cold, is often used in low-temperature applications (<120℃). Because water undergoes a phase change when used for cold storage, it performs latent heat energy storage, resulting in a high cold storage density when water is used as a cold storage medium; however, when used for heat storage, it performs sensible heat energy storage, resulting in a lower heat storage density. Phase change materials store heat and cold in the form of latent heat, possessing high energy density, and are widely used in single heat storage or single cold storage operations. Therefore, water has significant advantages in cold storage applications, while phase change materials have significant advantages 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 hot-summer and cold-winter regions has been increasing. Therefore, in addition to cooling needs in summer, these regions also have heating needs in winter; correspondingly, when using thermal storage heating technology, the use of thermal storage equipment must be considered. Currently, some equipment for thermal or cold storage has been published, such as a composite phase change thermal storage device (patent application number 202410043890.8), a finned tube phase change thermal storage device (patent application number 202311401519.6), and a multi-ribbed ice storage tube and ice storage tank (patent application number 202410146574.3), etc. However, these energy storage devices or methods can only achieve the purpose of thermal or cold storage alone; additional thermal or cold storage devices significantly increase costs and space requirements.

[0005] In summary, this invention combines the advantages of water and phase change materials, proposing an energy storage device that can be used for both heat and cold storage, reducing equipment costs and space requirements. Furthermore, both heat and cold storage involve a phase change process in the energy storage medium, enabling latent heat storage and resulting in high energy density. The device comprises several phase change units, allowing for flexible application scenarios by selecting the appropriate number of units. Summary of the Invention

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

[0007] Based on traditional hot water storage tanks, this invention combines sensible heat storage and phase change energy storage methods, incorporating phase change materials to increase the tank's heat storage density and efficiency. Simultaneously, during cold storage, the primary energy storage medium (water) stores energy in the form of latent heat, also exhibiting high cold storage density. This invention's device can be used for both heat and cold storage, demonstrating high energy storage density in both types of energy storage operations.

[0008] The technical solution of this invention:

[0009] An integrated composite heat and cold storage device includes a water tank, an insulation layer, a phase change unit, connecting pipes, a distributor, and a collector. The phase change unit has a phase change material filling cavity filled with phase change material. The phase change material filling cavity is fixed to the phase change unit by a supporting member. The connecting pipes connect each phase change unit in series and are placed entirely within the water tank. The distributor is connected to the upper connecting pipe and is connected to the heat exchange fluid inlet. The collector is connected to the lower connecting pipe and is connected to the heat exchange fluid outlet. During heat or cold storage, the water tank is filled with water. The heat exchange fluid enters the distributor from the heat exchange fluid inlet, is separated by the distributor, flows through the connecting pipes and the phase change unit, and finally enters the collector and exits from the heat exchange fluid outlet. While flowing through the connecting pipes, the heat exchange fluid exchanges heat with the water in the water tank. While flowing through the phase change unit, the heat exchange fluid exchanges heat with both 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 cuboid or a cylinder.

[0011] Furthermore, the water tank is covered with an insulation layer on the outside and is provided with a heat exchange fluid inlet and a heat exchange fluid outlet.

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

[0013] Furthermore, the phase change unit includes a shell, a supporting member, a phase change material filling cavity, and end caps at both ends; the end caps weld and fix the 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, which serve a sealing function; 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 while 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 by a support member, and the two are on the same central axis.

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

[0017] Furthermore, ribs are provided inside the phase change material filling cavity.

[0018] The beneficial effects of this invention are:

[0019] 1. This invention can be used in both thermal and cold storage scenarios, reducing equipment costs and space requirements.

[0020] 2. During heat or cold storage, the heat exchange fluid exchanges heat with two energy storage media (water in the 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 media, resulting in high energy storage density.

[0021] 3. During heat storage, the heat exchange fluid flows through the heat storage unit and channels, simultaneously releasing heat to the phase change material (PCM) and the water in the tank. The PCM absorbs the heat and undergoes a phase change, while the water in the tank absorbs heat and its temperature rises. In this process, the PCM stores latent heat and serves as the primary heat storage medium; the water stores sensible heat and serves as the auxiliary heat storage medium. During cold storage, the water in the tank becomes the primary cold storage medium. As the heat exchange fluid flows through the heat storage unit and channels, the water releases heat and undergoes a phase change, freezing on the outer walls of the channels and the PCM unit. Simultaneously, the heat exchange fluid also absorbs heat from the PCM; therefore, the PCM, as an auxiliary cold storage medium, also contributes to the cold storage capacity.

[0022] The device contains several phase change units, and the appropriate number of units can be selected according to different applications, making it flexible in application scenarios. Attached Figure Description

[0023] Figure 1This is a schematic diagram of the internal structure of the water tank in the device of the present invention.

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

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

[0026] Figure 4 This is a schematic diagram of the phase change unit of the device of the present invention.

[0027] Figure 5 This is a schematic diagram of the internal structure of the phase change unit of the device of the present invention.

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

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

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

[0031] In the diagram: 1. Phase change unit; 2. Connecting pipe; 3. Heat exchange fluid inlet; 4. Distributor; 5. Heat exchange fluid outlet; 6. Collector; 7. Water tank wall; 8. Insulation layer; 9. Fixing frame; 10. Phase change material filling cavity; 11. Rib; 12. Supporting component; 13. End cap; 14. Shell; 15. Outer wall of phase change material filling cavity; 16. Phase change material; 17. Heat exchange fluid flow channel. Detailed Implementation

[0032] The specific embodiments of the present invention will be further described below with reference to 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 and cold storage device with a structure similar to that of 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 by a fixing frame 9; the 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 pipes 2 connected to both ends. Figure 5As shown, the phase change unit 1 includes a shell 14, a phase change material filling cavity 10, a support member 12, and a cap 13. The connecting pipe 2 is welded to the phase change unit 1; the phase change material filling cavity 10 is filled with phase change material 16 and has ribs 11, and the phase change material 16 is sodium acetate trihydrate. Figure 6 As shown, the phase change material filling cavity 10 is welded to the end cap 13. To prevent the phase change material filling cavity 10 from becoming too long and bending, a support member 12 needs to be provided. In this embodiment, a semi-circular support member is used, and the member has fan-shaped through holes, such as... Figure 8 As shown. The installation process of phase change unit 1 is as follows: First, a suitable number of support components 12 are welded to the outer wall 15 of the phase change material filling cavity. Then, the phase change material filling cavity 10 is placed horizontally in the phase change unit 1. Finally, the end cap 13 is welded to the phase change material filling cavity 10 and the outer 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 "upward in and downward out".

[0036] During energy storage, the heat exchange fluid first enters the distributor 4 through the heat exchange fluid inlet 3, and then flows successively through the connecting pipe 2 and the phase change unit 1. 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 both the water in the water tank and the phase change material 16. After flowing through a corresponding number of phase change units 1, the heat exchange fluid enters the collector 6 and flows out from the heat exchange fluid outlet 5. During heat storage, water is used as the heat exchange fluid, and the main heat storage medium is the phase change material 16 located in the phase change unit 1, while the water in the water tank serves as the auxiliary heat storage medium. During cold storage, ethylene glycol is used as the heat exchange fluid, and the main cold storage medium is the water in the water tank, while the phase change material 16 in the phase change unit 1 serves as the auxiliary cold storage medium.

Claims

1. An integrated composite heat and cold storage device, characterized in that, This integrated composite heat and cold storage device includes a water tank, an insulation layer, a phase change unit, connecting pipes, a distributor, and a collector. The phase change unit has a phase change material filling cavity, which is filled with phase change material. The phase change material filling cavity is fixed to the phase change unit by supporting components. The connecting pipes connect each phase change unit in series and are placed entirely within the water tank. The distributor is connected to the upper connecting pipe and is connected to the heat exchange fluid inlet. The collector is connected to the lower connecting pipe and is connected to the heat exchange fluid outlet. During heat or cold storage, the water tank is filled with water. The heat exchange fluid enters the distributor from the heat exchange fluid inlet, is separated by the distributor, flows through the connecting pipes and the phase change unit, and finally enters the collector and exits from the heat exchange fluid outlet. While flowing through the connecting pipes, the heat exchange fluid exchanges heat with the water in the water tank. While flowing through the phase change unit, the heat exchange fluid exchanges heat with both the water in the water tank and the phase change material in the phase change unit. The phase change unit includes a shell, a supporting member, a phase change material filling cavity, and end caps at both ends. The end caps weld and fix the 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, which serve as a seal. The phase change material filling cavity is horizontally arranged in the phase change unit through the supporting member. A heat exchange fluid 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 exchanges heat with the energy storage medium inside and outside the phase change unit while flowing through the heat exchange fluid channel.

2. The integrated composite heat and cold storage device according to claim 1, characterized in that, The water tank is in the shape of a cuboid or cylinder, with an insulation layer on the outside and a heat exchange fluid inlet and outlet.

3. The integrated composite heat and cold storage device according to claim 1, characterized in that, The water tank is equipped with a fixed frame to secure the phase change unit and connecting pipes.

4. The integrated composite heat and cold storage device according to claim 1, characterized in that, The phase change unit is cylindrical in shape.

5. The integrated composite heat and cold storage device according to claim 1, characterized in that, The phase change material filling cavity is arranged inside the phase change unit by a support member, and the two are on the same central axis.

6. The integrated composite heat and cold storage device according to claim 1, characterized in that, The supporting member is welded to the outer wall of the phase change material filling cavity. It is semi-circular in shape, and the through hole on its cross-section is fan-shaped.

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

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