Multi-structure coupled long-period soil heat storage device
By employing a multi-structure coupling design in the soil thermal storage device, including different types of thermal storage wells and distribution water systems, a temperature field gradient with a dense inner layer and a sparse outer layer is formed, solving the problem of heat loss in existing devices and achieving efficient long-term thermal storage effect.
Patent Information
- Application Number
- CN202511774537.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-28
- Publication Date
- 2026-01-27
AI Technical Summary
Existing shallow soil buried pipe thermal storage devices suffer from significant heat loss through longitudinal and radial paths, resulting in low thermal storage efficiency. Furthermore, traditional designs fail to optimize high and low temperature thermal storage zones based on temperature field distribution patterns, leading to unreasonable heat distribution and limiting thermal storage capacity and system energy efficiency.
A multi-structure coupled long-term soil thermal storage device is adopted. By dividing the central area, intermediate ring area and outer peripheral area in the radial direction, different types of thermal storage wells are arranged. Combined with high temperature and low temperature water distribution system, a temperature field gradient with dense inner and sparse outer is formed. The characteristics of thermal storage wells with coaxial sleeve and U-shaped tube structure are utilized, combined with top insulation board, to reduce heat loss.
It significantly improves thermal storage efficiency, reduces heat loss in both the radial and longitudinal directions, achieves long-term high-efficiency thermal storage, and provides support for the low-carbonization and efficient operation of energy systems.
Smart Images
Figure CN121409025A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of renewable energy storage technology, specifically to a multi-structure coupled long-term soil thermal storage device. Background Technology
[0002] In recent years, with the transformation and construction of my country's new power energy system, long-cycle thermal storage technology has become one of the key paths to ensure the flexibility and reliability of energy supply, especially for cross-seasonal heating and cooling and the absorption of intermittent renewable energy (such as solar and wind power).
[0003] However, existing shallow soil buried pipe thermal storage devices have significant drawbacks. First, due to the large surface area to volume ratio of shallow thermal storage bodies, heat is primarily lost vertically upwards and radially outwards, severely limiting long-term thermal storage efficiency. Second, traditional thermal storage well designs often employ uniform spacing and depth, failing to optimize high and low temperature thermal storage zones based on the actual temperature field distribution within the storage body. This results in irrational heat distribution, further exacerbating heat loss and limiting storage capacity and overall system energy efficiency.
[0004] Therefore, there is an urgent need for a long-term soil thermal storage device that can effectively reduce heat loss and improve thermal storage efficiency. Summary of the Invention
[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a multi-structure coupled long-term soil thermal storage device. This device can significantly reduce heat loss and improve long-term thermal storage efficiency by optimizing the structure, layout and fluid distribution strategy of the thermal storage well.
[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: This invention provides a multi-structure coupled long-term soil thermal storage device, comprising: A cylindrical soil thermal storage body is divided radially from the inside out into a central area, an intermediate ring area, and an outer peripheral area. Shallow thermal storage wells are arranged in the central area and the intermediate ring area, while medium-deep thermal storage wells are arranged in the outer peripheral area. Short-term hot water storage tank; A high-temperature water distribution system, comprising a primary high-temperature water distributor and several secondary high-temperature water distributors, wherein a short-term hot water storage tank is connected to the primary high-temperature water distributor via a pipeline, and the secondary high-temperature water distributor comprises a secondary high-temperature water distributor and a secondary high-temperature water collector, wherein the primary high-temperature water distributor, the secondary high-temperature water distributor, the shallow thermal storage well in the central area or the medium-deep thermal storage well in the outer perimeter area, and the secondary high-temperature water collector are connected sequentially via pipelines. The low-temperature water distribution system includes a primary low-temperature water distributor and several secondary low-temperature water distributors. A short-term hot water storage tank is connected to the primary low-temperature water distributor via a pipeline. The secondary low-temperature water distributor includes a secondary low-temperature water distributor and a secondary low-temperature water collector. The primary low-temperature water distributor, the secondary low-temperature water distributor, the shallow thermal storage well in the intermediate ring area, and the secondary high-temperature water collector are connected in a sequential loop via pipelines.
[0007] Furthermore, it also includes a high-temperature circulating water pump, a low-temperature circulating water pump, and a PLC temperature and flow control cabinet. The high-temperature circulating water pump is installed on the water supply pipeline between the primary high-temperature manifold and the short-term hot water storage tank, and the low-temperature circulating water pump is installed on the water supply pipeline between the primary low-temperature manifold and the short-term hot water storage tank. Both the high-temperature circulating water pump and the low-temperature circulating water pump are electrically connected to the independently installed PLC temperature and flow control cabinet.
[0008] Furthermore, temperature transmitters and electric valves are installed on the water supply and return pipes between the primary high-temperature manifold and the short-term hot water storage tank, and the temperature transmitters and electric valves are electrically connected to the PLC temperature and flow control cabinet.
[0009] Furthermore, a top insulation board is installed at the bottom of the frozen soil layer of the soil heat storage body.
[0010] Furthermore, the number of medium-deep thermal storage wells and shallow thermal storage wells accounts for 20% and 80% of the total number of thermal storage wells, respectively; the ratio of the radius of the central area to the diameter of the intermediate ring area is 1:1.
[0011] Furthermore, the spacing between the thermal storage wells arranged in the soil thermal storage body decreases radially from the outside to the inside, forming a structure that is dense inside and sparse outside.
[0012] Furthermore, the shallow thermal storage well adopts a U-shaped tube structure; the medium-deep thermal storage well adopts a coaxial casing structure.
[0013] Compared with the prior art, the beneficial technical effects of the present invention are as follows: This invention relates to a multi-structure coupled long-term soil thermal storage device. By combining the heat transport and storage characteristics of a coaxial sleeve structure for medium-deep thermal storage wells and a U-shaped tube structure for shallow thermal storage wells, a soil thermal storage body with a dense inner core and a sparse outer core, resembling an inverted concave cylinder, is formed. A high-low-high temperature gradient is created from the outside to the inside of the effective shallow thermal storage depth in the underground soil. This temperature gradient generates a thermal shielding effect around the thermal storage device, reducing heat loss in the radial direction and significantly improving the long-term thermal storage efficiency of the thermal storage body. It effectively stores heat at the center of the thermal storage body, providing strong support for the low-carbon and high-efficiency operation of energy systems. By adding a top insulation plate, the upward heat loss path is directly blocked, and combined with the radial thermal shielding effect, comprehensive suppression of the main heat loss directions is achieved. Attached Figure Description
[0014] Figure 1 This is a schematic diagram of the planar structure of the multi-structure coupled long-term soil thermal storage device of the present invention. Figure 2 This is a schematic diagram of the radial cross-sectional structure of the multi-structure coupled long-term soil thermal storage device of the present invention. Figure 3 This is a schematic diagram of the radial profile temperature field variation gradient of the multi-structure coupled long-term soil thermal storage device of the present invention. Figure 4 This is a schematic diagram of the structure of the medium-deep thermal storage well of the present invention; Figure 5 for Figure 4 Sectional view of AA in the middle; Figure 6 for Figure 4 Cross-sectional view of the middle section (BB); Figure 7 This is a schematic diagram of the shallow thermal storage well of the present invention; Figure 8 for Figure 7 CC section view; Reference numerals: 1-Medium-deep thermal storage well, 101-Outer casing, 102-Inner casing, 103-Cement annular wall, 2-Shallow thermal storage well, 201-U-tube, 202-Backfill material, 203-Borehole wall, 3-First-stage high-temperature manifold, 31-Second-stage high-temperature manifold, 311-Second-stage high-temperature distributor, 312-Second-stage high-temperature collector, 4-First-stage low-temperature manifold, 41-Second-stage low-temperature manifold, 411-Second-stage low-temperature distributor, 412-Second-stage low-temperature collector, 5-Short-term hot water storage tank, 6-High-temperature circulating water pump, 7-Low-temperature circulating water pump, 8-Temperature transmitter, 9-Electric valve, 10-PLC temperature and flow control cabinet, 11-Top insulation board. Detailed Implementation
[0015] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments.
[0016] like Figure 1 and 2 As shown, the present invention provides a multi-structure coupled long-term soil thermal storage device, comprising: A cylindrical soil thermal storage body is divided into a central area, an intermediate ring area and an outer peripheral area in the radial direction from the inside to the outside. Shallow thermal storage wells 2 are arranged in the central area and the intermediate ring area, and medium-deep thermal storage wells 1 are arranged in the outer peripheral area. Short-term hot water storage tank 5; A high-temperature water distribution system, comprising a primary high-temperature water distributor 3 and several secondary high-temperature water distributors 31, wherein a short-term hot water storage tank 5 is connected to the primary high-temperature water distributor 3 via a pipeline, and the secondary high-temperature water distributors 31 include secondary high-temperature water distributors 311 and secondary high-temperature water collectors 312. The primary high-temperature water distributor 3, the secondary high-temperature water distributor 311, the shallow thermal storage well 2 in the central area or the medium-deep thermal storage well 1 in the outer perimeter area, and the secondary high-temperature water collectors 312 are connected sequentially via pipelines. The low-temperature water distribution system includes a primary low-temperature water distributor 4 and several secondary low-temperature water distributors 41. A short-term hot water storage tank 5 is connected to the primary low-temperature water distributor 4 via a pipeline. The secondary low-temperature water distributors 41 include a secondary low-temperature water distributor 411 and a secondary low-temperature water collector 412. The primary low-temperature water distributor 4, the secondary low-temperature water distributor 411, the shallow thermal storage well 2 in the intermediate ring area, and the secondary high-temperature water collector 312 are connected in a sequential loop via pipelines.
[0017] In this embodiment, the soil thermal storage body is an underground thermal storage component, while the short-term hot water storage tank 5, the high-temperature water distribution system, and the low-temperature water distribution system are located above ground. The short-term hot water storage tank is used to receive and temporarily store hot water from renewable energy systems (such as solar collectors).
[0018] Specifically, it also includes a high-temperature circulating water pump 6, a low-temperature circulating water pump 7, and a PLC temperature and flow control cabinet 10. The high-temperature circulating water pump 6 is installed on the water supply pipeline between the primary high-temperature manifold 3 and the short-term hot water storage tank 5, and the low-temperature circulating water pump 7 is installed on the water supply pipeline between the primary low-temperature manifold 4 and the short-term hot water storage tank 5. Both the high-temperature circulating water pump 6 and the low-temperature circulating water pump 7 are electrically connected to the independently installed PLC temperature and flow control cabinet 10.
[0019] Specifically, temperature transmitters 8 and electric valves 9 are installed on the water supply and return pipes between the primary high-temperature manifold 3 and the short-term hot water storage tank 5. The temperature transmitters 8 and electric valves 9 are electrically connected to the PLC temperature and flow control cabinet 10. The temperature transmitters 8 are installed on the outlet pipe of the short-term hot water storage tank to monitor the output water temperature in real time.
[0020] Specifically, the bottom of the frozen soil layer of the soil heat storage body is equipped with a top surface insulation board 11, which can reduce the vertical upward heat loss.
[0021] As a preferred option, the number of medium-deep thermal storage wells 1 and shallow thermal storage wells 2 accounts for 20% and 80% of the total number of thermal storage wells, respectively; the ratio of the radius of the central area to the diameter of the intermediate ring area is 1:1.
[0022] Preferably, the spacing between the thermal storage wells arranged in the soil thermal storage body decreases radially from the outside to the inside, forming an inverted "concave" cylindrical structure with a denser inner surface and a sparser outer surface.
[0023] like Figure 4-6 As shown, in a preferred embodiment of the present invention, the medium-deep thermal storage well 1 adopts a coaxial casing structure. The medium-deep thermal storage well 1 includes an inner casing 102, an outer casing 101, and a cement annular wall 103. The inner casing 102 and the outer casing 101 are coaxially arranged and their lower ends are connected. The cement annular wall 103 is disposed outside the outer casing 101.
[0024] like Figure 4-6 As shown, in a preferred embodiment of the present invention, the shallow thermal storage well 2 adopts a U-shaped tube structure; the shallow thermal storage well 2 includes a borehole wall 203 and a U-shaped tube 201 disposed inside the borehole wall 203. The cavity between the U-shaped tube 201 and the borehole wall 203 is filled with backfill material 202, which is soil, sand and gravel or bentonite cement.
[0025] The working process of this invention is as follows: During the thermal storage phase, the heat generated by renewable energy is stored in a short-term hot water storage tank, and the temperature transmitter 8 continuously monitors the output water temperature of the tank. The PLC temperature and flow control cabinet 10 makes decisions based on the water temperature. When the water temperature is high, the PLC temperature and flow control cabinet 10 is started, and the electric valve 9 on the heat source side of the corresponding pipeline is opened, so that the high temperature water is preferentially injected into the shallow heat storage well 2 in the central area and the medium and deep heat storage well 1 in the outer area of the soil heat storage body through the first-stage high temperature water manifold 3 and the second-stage high temperature water manifold 31. When the water temperature is low, the PLC temperature and flow control cabinet 10 can start the low-temperature circulating water pump 7 and open the electric valve 9 of the corresponding pipeline to inject low-temperature water into the shallow thermal storage well 2 in the middle ring area of the soil thermal storage body through the first-stage low-temperature water distributor 4 and the second-stage low-temperature water distributor 41.
[0026] Through this intelligent allocation, and after a period of continuous operation, within the effective heat storage depth of the underground soil, a system like... Figure 3 The temperature gradient shown is as follows: from the periphery of the thermal storage body inwards, the temperature first increases (entering the high-temperature zone), then decreases (into the outer low-temperature barrier zone), and finally increases again in the core region. This "high-low-high" gradient structure allows the outer low-temperature zone to act as a thermal shield for the inner high-temperature zone, effectively suppressing the radial diffusion of heat to all directions. At the same time, the top insulation plate 11 suppresses upward heat loss.
[0027] The heat extraction process can extract heat at different temperatures from the corresponding manifolds for heating or other purposes by controlling water pumps and valves as needed.
[0028] The above are merely embodiments of the present invention, described in a relatively specific and detailed manner, but should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.
Claims
1. A multi-structure coupled long-term soil thermal storage device, characterized in that, include: A cylindrical soil thermal storage body is divided radially from the inside out into a central area, an intermediate ring area, and an outer peripheral area. Shallow thermal storage wells are arranged in the central area and the intermediate ring area, while medium-deep thermal storage wells are arranged in the outer peripheral area. Short-term hot water storage tank; A high-temperature water distribution system, comprising a primary high-temperature water distributor and several secondary high-temperature water distributors, wherein a short-term hot water storage tank is connected to the primary high-temperature water distributor via a pipeline, and the secondary high-temperature water distributor comprises a secondary high-temperature water distributor and a secondary high-temperature water collector, wherein the primary high-temperature water distributor, the secondary high-temperature water distributor, the shallow thermal storage well in the central area or the medium-deep thermal storage well in the outer perimeter area, and the secondary high-temperature water collector are connected sequentially via pipelines. The low-temperature water distribution system includes a primary low-temperature water distributor and several secondary low-temperature water distributors. A short-term hot water storage tank is connected to the primary low-temperature water distributor via a pipeline. The secondary low-temperature water distributor includes a secondary low-temperature water distributor and a secondary low-temperature water collector. The primary low-temperature water distributor, the secondary low-temperature water distributor, the shallow thermal storage well in the intermediate ring area, and the secondary high-temperature water collector are connected in a sequential loop via pipelines.
2. The multi-structure coupled long-term soil thermal storage device according to claim 1, characterized in that: It also includes a high-temperature circulating water pump, a low-temperature circulating water pump, and a PLC temperature and flow control cabinet. The high-temperature circulating water pump is installed on the water supply pipeline between the primary high-temperature manifold and the short-term hot water storage tank, and the low-temperature circulating water pump is installed on the water supply pipeline between the primary low-temperature manifold and the short-term hot water storage tank. Both the high-temperature circulating water pump and the low-temperature circulating water pump are electrically connected to the independently installed PLC temperature and flow control cabinet.
3. The multi-structure coupled long-term soil thermal storage device according to claim 2, characterized in that: Temperature transmitters and electric valves are installed on the water supply and return pipes between the primary high-temperature manifold and the short-term hot water storage tank. The temperature transmitters and electric valves are electrically connected to the PLC temperature and flow control cabinet.
4. The multi-structure coupled long-term soil thermal storage device according to claim 1, characterized in that: The bottom of the frozen soil layer of the soil heat storage body is equipped with a top surface insulation board.
5. A multi-structure coupled long-term soil thermal storage device according to claim 1, characterized in that: The number of medium-deep thermal storage wells and shallow thermal storage wells accounts for 20% and 80% of the total number of thermal storage wells, respectively; the ratio of the radius of the central area to the diameter of the intermediate ring area is 1:
1.
6. The multi-structure coupled long-term soil thermal storage device according to claim 1, characterized in that: The spacing between the thermal storage wells arranged in the soil thermal storage body decreases radially from the outside to the inside, forming a structure that is dense inside and sparse outside.
7. The multi-structure coupled long-term soil thermal storage device according to claim 1, characterized in that: The shallow thermal storage well adopts a U-shaped tube structure; the medium-deep thermal storage well adopts a coaxial casing structure.