Sand storage tank system with layered heat storage and heat release functions

Abstract

The invention discloses a sand storage tank system capable of storing and releasing heat in a layered mode. The sand storage tank system comprises an energy storage assembly, a monitoring system and a supporting structure. The energy storage assembly is used for containing sand for energy storage and providing a place for heat exchange between the heat exchange working medium and the sand; the monitoring system is used for monitoring the energy storage state of each sand storage layer in the energy storage assembly in real time; in the heat storage process, whether sand in the sand storage layer can store heat or not and whether the sand storage layer storing heat or not completes heat storage or not are judged; in the heat release process, whether sand in the layer can release heat or not and whether the sand storage layer releasing heat or not are subjected to heat release or not are judged; the supporting structure is used for supporting the whole energy storage assembly and the monitoring system. Full-process automatic operation can be achieved in the operation process, manual intervention is reduced, and energy waste is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage, in particular to a layered heat storage and release sand storage tank system. BACKGROUND

[0002] At present, energy storage technologies mainly include mechanical energy storage, electromagnetic energy storage, electrochemical energy storage, thermal energy storage, and hydrogen energy storage. Among them, mechanical energy storage and thermal energy storage are more suitable for large-scale energy storage. For thermal energy storage, the commonly used heat storage materials include molten salt, ceramic, heat conducting oil, sand, and concrete, etc. The most commonly used material is molten salt, but due to the high solidification point temperature of molten salt, the system often needs to be continuously operated at a high temperature, and is prone to solidification, which leads to blockage of the heat storage pipeline and corrosion of the equipment. Compared with molten salt, sand has the characteristics of high thermal stability temperature, low price, easy to obtain, and no need for processing, etc., and is an ideal heat storage material.

[0003] For an energy storage system, the storage / heat release power and the energy storage capacity are important operating parameter indicators. The way of sand storage / heat release will directly affect the heating efficiency, and the direct flow of heat exchange medium through the sand storage tank and the sand for heat exchange helps to improve the heat exchange efficiency and increase the storage / heat release power. In order to increase the heat storage capacity, a large amount of sand needs to be filled in the sand storage tank.

[0004] However, the simple accumulation of sand in the sand storage tank will cause a huge resistance loss, increase the energy consumption of the heat storage system, and increase the energy storage cost.

[0005] A flow sand energy storage system coupled with heat storage and gravity energy storage and an operation method thereof are disclosed in CN 119289745 A. When the energy supply is sufficient, the system heats the flow sand by electric heating rods after lifting the sand height through compressed air and electric heating. When the energy supply is insufficient, the system first exchanges heat with the flow sand heat exchanger, generates electricity using the heat of the sand, and then uses the gravity potential energy of the cooled sand to impact the sand wheel machine to generate electricity.

[0006] However, the disclosed scheme has the following disadvantages: (1) The electric heating rods cannot fully contact the sand, and this heating method needs to rely on the heat conduction of air to heat the sand, which has low heating efficiency; (2) The operation mode of the air and flow sand heat exchanger is not given, and it is unknown how the air takes away the heat from the sand during the heat release process.

[0007] Therefore, there is an urgent need for a technology that can guarantee the storage / heat release power, reduce the resistance loss, and reduce the energy storage cost while having large-scale heat storage capacity. SUMMARY

[0008] In order to overcome the defects of the prior art, the present application provides a sand storage tank system with layered heat storage and release, in which the heat exchange medium directly contacts with sand to complete heat exchange, and the heat exchange efficiency is significantly improved. During operation, full automation can be realized, manual intervention is reduced, and energy waste is avoided.

[0009] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is:

[0010] A sand storage tank system with layered heat storage and release, comprising an energy storage assembly, a monitoring system and a support structure.

[0011] The energy storage assembly is used to accommodate energy storage sand and provide a place for heat exchange between the heat exchange medium and the sand.

[0012] The monitoring system is used to monitor the energy storage state of each sand storage layer in the energy storage assembly in real time; to determine whether the sand in the sand storage layer can store heat during the heat storage process, whether the sand storage layer that is storing heat is complete; to determine whether the sand in the layer can release heat during the heat release process, and whether the sand storage layer that is releasing heat is complete.

[0013] The support structure is used to support the entire energy storage assembly and monitoring system. It is the structural framework of the entire system.

[0014] The energy storage assembly comprises any number of series heat exchange units, each heat exchange unit comprising a sand storage layer, a flow equalization layer and a low resistance channel. The flow equalization layer is arranged on both sides of any sand storage layer, and the low resistance channel penetrates the sand storage layer.

[0015] The sand storage layer is arranged in multiple layers from top to bottom; the heat exchange medium enters from above the sand storage layer and leaves from below during the heat storage and release process; or enters from below and leaves from above, and the flow direction is not fixed.

[0016] The sand storage layer is fixed by the support structure, and a porous baffle is arranged on both sides of the sand storage layer. The porous baffle ensures that the heat exchange medium passes through and the sand does not leak. The porous baffle is a baffle with pores that ensure that the sand does not leak out and the heat exchange medium can flow in.

[0017] The series means that the heat exchange medium can flow through each layer of sand storage layer in turn.

[0018] The shape of the sand storage layer, the flow equalization layer and the low resistance channel is not limited, and their shape and arrangement position can be selected in various ways, but they must have all three.

[0019] The sand storage layer and the low resistance channel are arranged at the same height and are repeatedly arranged with the flow equalization layer in the flow direction of the heat exchange medium.

[0020] The flow equalization layer is an open flow space in which the heat exchange medium can flow freely, and its purpose is to re-distribute the flow of the heat exchange medium and improve the uniformity of the flow into each position of the sand storage layer.

[0021] The low-resistance channel is a through flow path dug in the sand storage layer, which is completely through and directly connected to the flow equalization layers on the upper and lower sides, and the sand storage layer is arranged with sand.

[0022] Since the low-resistance channel is open, its flow resistance is much smaller than that in the sand storage layer, so the heat exchange medium almost does not flow through the sand storage layer; when the low-resistance channel is closed (closed by the valve), the heat exchange medium can only flow through the sand storage layer.

[0023] The monitoring system includes temperature sensors, electric valves, and an automatic control system.

[0024] The sand storage layer of any heat exchange unit is arranged with a temperature sensor, and the low-resistance channel is arranged with an electric valve.

[0025] The temperature sensor is used to measure the sand storage temperature or the flow medium temperature at each position of the sand storage layer.

[0026] Temperature sensor 1T is arranged outside the bottom layer of the sand storage layer, temperature sensor 2T is arranged inside the bottom layer of the sand storage layer, temperature sensor 3T is arranged inside the top of the sand storage layer, and temperature sensor 4T is arranged outside the top of the sand storage layer.

[0027] The low-resistance channel is an open channel, and the side wall of the low-resistance channel is in contact with the sand storage layer and is completely closed, so the heat exchange medium cannot pass through the side wall; the lower inlet and outlet of the low-resistance channel is arranged with an electric valve one.

[0028] The upper inlet and outlet of the low-resistance channel is arranged with an electric valve two.

[0029] Temperature sensor 1T and temperature sensor 4T are used to measure the temperature of the heat exchange medium, and temperature sensor 2T and temperature sensor 3T are used to measure the sand storage temperature.

[0030] When the heat exchange medium flows from top to bottom, temperature sensor 4T and temperature sensor 2T work; taking the heat storage process as an example: temperature sensor 4T measures the temperature of the heat exchange medium, and when its temperature reaches or exceeds the specified parameter, it indicates that the temperature of the heat exchange medium heated in the previous layer is still high, and heat can continue to be transferred, so the low-resistance channel needs to be closed (the electric valve is closed), and the heat exchange medium flows from the sand storage layer to transfer heat. When the sand temperature measured by temperature sensor 2T reaches or exceeds the specified parameter, the sand in this layer has reached the expected heat storage capacity, and the low-resistance channel is closed (the electric valve is opened), and the heat exchange medium flows through the low-resistance channel without heating the sand layer.

[0031] When the heat exchange medium flows from bottom to top, temperature sensor 1T and temperature sensor 3T work, and the process is similar to the above process.

[0032] The electric valve is used to control the opening and closing of the low-resistance channel.

[0033] Temperature sensor 1T and temperature sensor 4T are used to measure the temperature of the heat exchange medium, and temperature sensor 2T and temperature sensor 3T are used to measure the temperature of the sand storage; measuring the temperature of the heat exchange medium is used to determine the start of the heating process, and measuring the temperature of the sand storage is used to determine the end of the heat storage process.

[0034] The electric valve is used to control the opening and closing of the low-resistance channel, and thus realizes the effect of heating only the specified sand storage layer, i.e. layered heating.

[0035] The heat storage assembly is arranged with an insulating layer on the outside to reduce heat loss between the system and the outside; the inlet flow distribution manifold and the outlet flow distribution manifold are arranged at both ends of the heat storage assembly, and have the same structure, which is used to homogenize the heat exchange medium flowing through the sand layer.

[0036] The inlet flow distribution manifold is connected with the heat exchange medium inlet pipeline, and the outlet flow distribution manifold is connected with the heat exchange medium outlet pipeline, i.e. the heat exchange medium enters the inlet flow distribution manifold through the inlet pipeline, and then completes heat exchange in the system. After the heat exchange is completed, it enters the outlet pipeline through the outlet distribution manifold and leaves.

[0037] Each temperature sensor and electric valve is connected with a control module; in the automatic control system, temperature thresholds are set, and in the actual working process, automatic control is realized through the operation of the automatic control system; the control module is an execution unit of the automatic control system, which is used to execute the commands of the automatic control system;

[0038] The automatic control system realizes the control of the electric valve according to the temperature sensor signal, and realizes the goal of heating the sand in each sand storage layer from the inlet to the outlet of the sand storage tank system.

[0039] The automatic control steps of any sand storage layer for heat storage / heat release are as follows:

[0040] The heat storage process of sand storage layer X:

[0041] (1) When the temperature of temperature sensor 1T in sand storage layer X reaches (or is higher than) the set temperature value T, it indicates that the heating of (X-1) layer sand storage has been completed, and the control electric valve is closed, and the low-resistance channel of sand storage layer X is closed.

[0042] (2) The low-resistance channel is closed, the heat exchange fluid flows through the sand storage layer, and completes heat exchange with the sand storage in the sand storage layer, and the temperature of the sand gradually rises;

[0043] (3) The sand in the sand storage layer X reaches the expected heat storage capacity, i.e., the heat storage process of the sand storage layer X is completed; at this time, the temperature sensor 3T reaches the set value T', the control electric valve is opened, and the low-resistance passage of the sand storage layer X is opened;

[0044] (4) The heat exchange fluid passes through the sand storage layer X through the low-resistance passage and does not exchange heat with the sand, and the temperature reaches (or is higher than) the set temperature T;

[0045] (5) The sand storage layer (X+1) repeats the processes (1)-(4) to complete the heat storage process;

[0046] The heat release process of the sand storage layer X:

[0047] (1) When the temperature sensor 4T in the sand storage layer X reaches (or is lower than) the set temperature value t, at this time, it indicates that the heat release of the sand storage layer (X+1) is completed, the control electric valve 2 is closed, and the low-resistance passage 2 of the sand storage layer X is closed;

[0048] (2) The low-resistance passage 2 is closed, the heat exchange fluid flows through the sand storage layer, and the heat exchange between the sand and the heat exchange fluid is completed, and the temperature of the sand gradually decreases;

[0049] (3) The sand in the sand storage layer X reaches the expected heat storage capacity, i.e., the heat storage process of the sand storage layer X is completed; at this time, the temperature sensor 3T reaches the set value T', the control electric valve is opened, and the low-resistance passage of the sand storage layer X is opened;

[0050] (4) The heat exchange fluid passes through the sand storage layer X through the low-resistance passage and does not exchange heat with the sand, and the temperature reaches (or is lower than) the set temperature T;

[0051] (5) The sand storage layer (X+1) repeats the processes (1)-(4) to complete the heat storage process;

[0052] The beneficial effects of the present application are as follows:

[0053] In the present application, the heat exchange fluid directly contacts the sand to complete heat exchange, and the heat exchange efficiency is significantly improved. Moreover, the heat storage system is controlled by the control system throughout the whole process, automatic operation can be realized, and labor cost is reduced.

[0054] In the sand storage tank system, the sand is stored in the tank for a long time and is in a static state, and the sand does not need to be frequently moved, so that energy consumption is reduced. The fixed arrangement form reduces the abrasion of the structure caused by the flow of sand, and prolongs the service life of the sand storage tank system.

[0055] In the sand storage tank system, the sand is heated layer by layer, only the sand storage layer in the heat storage / release state has a large resistance loss, the heat exchange fluid passes through the low-resistance passage and flows through the remaining sand storage layers, and the resistance loss is very small, so that the resistance loss in the heat storage / release process is effectively controlled, and energy consumption is reduced.

[0056] The resistance loss of the sand storage tank system in the heat storage and release process is only related to the design parameters of a single sand storage layer, and is not related to the number of sand storage layers in the system. Therefore, the sand storage capacity of the sand storage pipe system can be increased as much as possible within the range that the tank support system can withstand, matching the required heat storage capacity of the actual project, and having wider applicability. BRIEF DESCRIPTION OF DRAWINGS

[0057] Figure 1 The figure is a schematic diagram of the energy storage system of the present application.

[0058] Figure 2 The figure is an example layout of the energy storage unit.

[0059] Figure 3 The figure is an example layout of the monitoring system.

[0060] Figure 4 The figure is a logic diagram of the automatic control system.

[0061] The various reference numbers in the figure represent:

[0062] 1 inlet / outlet distribution manifold; 2 low resistance channel; 3 sand storage layer; 4 flow equalization layer; 5 porous baffle; 6 support structure; 7 thermal insulation layer; 8 outlet / inlet distribution manifold; 9-12 temperature sensors; 13, 14 electric valves; 15 automatic control system. DETAILED DESCRIPTION

[0063] The present application will be further described in detail below with reference to the accompanying drawings.

[0064] EMBODIMENT

[0065] The embodiment discloses a layered sand storage tank system for storing and releasing heat, which includes an energy storage assembly, a monitoring system, and a support assembly.

[0066] The energy storage assembly is the main functional module of the entire system, and is a place where sand and heat exchange working medium complete heat exchange, and is composed of a sand storage layer, a flow equalization layer, and a low resistance channel, as shown in Figure 1 .

[0067] The sand storage layer 3 and the flow equalization layer 4 are arranged in the sand storage tank. When any sand storage layer 3 is in a heat storage and release state, the heat exchange working medium flows through the flow equalization layer 4 and is redistributed to uniformly flow through the sand storage layer 3 to realize the heat transfer process, and the resistance loss of this process is large. The low resistance channel 2 penetrates through all the sand storage layers in the flow direction of the heat exchange working medium in the tank. When any sand storage layer 3 is in a non-heat storage and release state, the heat exchange working medium flows through the low resistance channel 2 to reduce the flow resistance loss. The thicknesses of the sand storage layer 3 and the flow equalization layer 4 depend on the actual engineering design. The thickness of the sand storage layer 3 needs to meet the following conditions:

[0068] (1) the heat transfer required can be completed; and (2) the flow resistance loss is within an acceptable range.

[0069] The thickness of the flow uniformity layer 4 needs to meet the requirement of ensuring that the heat exchange medium flows uniformly through the sand storage layer 3.

[0070] The position of the low-resistance channel 2 needs to meet the requirements of:

[0071] (1) facilitating the realization of channel valve control; (2) helping the heat exchange medium to flow uniformly through the sand storage layer 3.

[0072] In the packed bed heat exchange system, during the heat exchange process, the packed sand can be divided into three layers. Taking the heating process as an example: according to the flow direction of the heat exchange medium, the temperatures of the three layers of sand are the inlet temperature of the heat exchange medium, the temperature gradient layer, and the outlet temperature of the heat exchange medium. That is, during the process of heating the sand, only the sand in the temperature gradient layer exchanges heat with the heat exchange medium, and the sand in the remaining positions increases the resistance loss of the flow process. Layered heating is to reduce this part of the loss.

[0073] The shape, arrangement, and number of low-resistance channels 2 of the sand storage layer 3 and the flow uniformity layer 4 in the energy storage system are not limited, Figure 2 There are three example arrangements, each with different shapes, arrangements, and numbers of low-resistance channels. In the example arrangement, the low-resistance channels are uniformly arranged in the sand storage layer to promote flow uniformity.

[0074] The monitoring system is the core module for stable operation of the entire system, and the control of the layered heating process is realized by monitoring the temperature. The monitoring system is composed of temperature sensors, electric valves, and an automatic control system. Figure 3 For the example monitoring system layout, temperature sensor 1T9 and temperature sensor 4T12 are arranged on the surface of the sand storage layer, and temperature sensor 2T10 and temperature sensor 3T11 are arranged in the sand storage layer 3; electric valve 1 13 and electric valve 2 14 are arranged at the upper and lower entrances of the low-resistance channel. Figure 4 For the automatic control system logic diagram. During the heat storage / release process, the energy storage system starts from the sand storage layer 3 near the inlet position of the heat exchange medium and transfers heat layer by layer, and the maximum heat storage / release process ends after the heat transfer of the sand storage layer 3 closest to the outlet position of the heat exchange medium is completed. In actual engineering, there is enough sand in the sand storage tank, and only part of the sand layer needs to complete the heat storage / release cycle in the daily cycle of heat storage / release.

[0075] Taking the arrangement in the middle as an example, the example control process is as follows: Figure 3

[0076] Heat storage process of sand storage layer X:

[0077] (1) When the temperature of temperature sensor 1T in sand storage layer X reaches (or is higher than) the set temperature value T, it indicates that the heating of the (X-1) layer of sand storage has been completed, and the control electric valve 1A is closed, and the low-resistance channel of the sand storage layer X is closed.​

[0078] (2) The low-resistance channel is closed, and the heat exchange fluid flows through the sand storage layer, exchanges heat with the sand in the layer, and the temperature of the sand gradually rises.

[0079] (3) The sand storage layer X completes the heat storage process, and the temperature sensor 3T reaches the set value T'. The control electric valve 1A is opened, and the low-resistance channel of the sand storage layer X is opened.

[0080] (4) The heat exchange fluid passes through the sand storage layer X through the low-resistance channel, does not exchange heat with the sand, and the temperature reaches (or is higher than) the set temperature T.

[0081] (5) The sand storage layer (X+1) repeats the processes (1)-(4) to complete the heat storage process.

[0082] Heat release process of sand storage layer X:

[0083] (1) When the temperature sensor 4T in the sand storage layer X reaches (or is lower than) the set temperature value t, it indicates that the heat release of the (X+1) layer sand storage has been completed, and the control electric valve 1a is closed. The low-resistance channel of the sand storage layer X is closed.

[0084] (2) The low-resistance channel is closed, and the heat exchange fluid flows through the sand storage layer, exchanges heat with the sand in the layer, and the temperature of the sand gradually rises.

[0085] (3) The sand storage layer X completes the heat release process, and the temperature sensor 2T reaches the set value t'. The control electric valve 1a is opened, and the low-resistance channel of the sand storage layer X is opened.

[0086] (4) The heat exchange fluid passes through the sand storage layer X through the low-resistance channel, does not exchange heat with the sand, and the temperature reaches (or is lower than) the set temperature t.

[0087] (5) The sand storage layer (X-1) repeats the processes (1)-(4) to complete the heat release process.

[0088] The support assembly is the guarantee for the stable operation of the entire system, which is composed of a sand storage tank body, an insulation layer, and a flow distribution pipeline. The shape of the sand storage tank body is not limited, which can provide support for the sand storage layer 3 and ensure that the sand does not leak out through the filter plate, and the heat exchange medium can flow through. The insulation layer effectively reduces the heat dissipation of the sand storage tank to the outside, ensuring long-term stability of heat storage. The flow distribution manifold pre-distributes the flow to the dispersed low-resistance channels 2, ensuring that the heat exchange medium can flow more uniformly through the sand storage layer 3 during the heat storage / release process.

Claims

1. A layered heat storage and release sand tank system, characterized by, The energy storage assembly, the monitoring system and the support structure (6) are included. The energy storage assembly is used for containing sand for energy storage and providing a place for heat exchange between the heat exchange medium and the sand. The monitoring system is used for real-time monitoring of the energy storage state of each sand storage layer (3) in the energy storage assembly; determining whether the sand in the sand storage layer (3) can store heat, whether the sand storage layer (3) that is storing heat is completed during the heat storage process; determining whether the sand in the layer can release heat, whether the sand storage layer (3) that is releasing heat is completed during the heat release process. The support structure (6) is used for supporting the entire energy storage assembly and the monitoring system.

2. The layered heat storing and releasing sand tank system according to claim 1, wherein, The energy storage assembly includes any number of series heat exchange units, each heat exchange unit including a sand storage layer (3), a flow equalization layer (4) and a low-resistance channel (2), and any sand storage layer (3) is arranged with flow equalization layers (4) on both sides, and the low-resistance channel (2) penetrates the sand storage layer (3).

3. The layered heat storing and releasing sand tank system according to claim 2, wherein, The sand storage layer (3) is arranged with multiple layers from top to bottom; the heat exchange medium enters from above and leaves from below during the heat storage and heat release process; or enters from below and leaves from above.

4. The layered heat storing and releasing sand tank system according to claim 2, wherein, The sand storage layer (3) is fixed by the support structure (6), and the sand storage layer (3) is arranged with porous baffles (5) on both sides, the porous baffles (5) are baffles with pores, the size of the pores ensures that the sand cannot leak out, and the heat exchange medium can flow into the pores; The series refers to the flow of the heat exchange medium through each layer of the sand storage layer (3) in turn.

5. The layered heat storing and releasing sand tank system according to claim 2, wherein, The sand storage layer (3) and the low-resistance channel (2) are arranged at the same height and are repeatedly arranged with the flow equalization layer (4) in the flow direction of the heat exchange medium. The flow equalization layer (4) is an open flow space, and the heat exchange medium can flow freely therein.

6. The layered heat storing and releasing sand tank system according to claim 2, wherein The low-resistance channel (2) is a through flow passage dug in the sand storage layer (3), directly connecting the flow equalization layers (4) on both sides, and the sand storage layer (3) is arranged with sand; The low-resistance channel (2) is an open channel, and the side wall of the low-resistance channel (2) is in contact with the sand storage layer (3) and is completely closed, and the heat exchange medium cannot pass through the side wall.

7. The layered heat storing and releasing sand tank system of claim 2, wherein The monitoring system includes temperature sensors, electric valves and an automatic control system (15); Any heat exchange unit is arranged with temperature sensors on the sand storage layer (3) and electric valves on the low-resistance channel (2); The temperature sensors are used for measuring the sand storage temperature or the flow medium temperature at each position of the sand storage layer (3); Temperature sensor 1T (9) is arranged outside the bottom layer of the sand storage layer (3), temperature sensor 2T (10) is arranged inside the bottom layer of the sand storage layer (3), temperature sensor 3T (11) is arranged inside the top of the sand storage layer (3), and temperature sensor 4T (12) is arranged outside the top of the sand storage layer (3); Electric valve one (13) is arranged at the inlet and outlet below the low-resistance channel (2); Electric valve two (14) is arranged at the inlet and outlet above the low-resistance channel (2). Temperature sensor 1T (9) and temperature sensor 4T (12) are used for measuring the temperature of the heat exchange medium, and temperature sensor 2T (10) and temperature sensor 3T (11) are used for measuring the sand storage temperature; Measuring the temperature of the heat exchange medium is used for determining the start of the heating process, and measuring the temperature of the sand storage is used for determining the end of the heat storage process; The electric valve is used for opening and closing the low-resistance passage (2), so as to realize the effect of heating only the specified sand storage layer (3), i.e. the effect of layered heating.

8. The layered heat storing and releasing sand tank system according to claim 7, wherein The heat insulation layer (7) is arranged outside the energy storage assembly, which is used for reducing the heat exchange loss between the system and the outside world; the inlet flow distribution manifold (1) and the outlet flow distribution manifold (8) are arranged at both ends of the energy storage assembly, which are the same in structure and are used for homogenizing the heat exchange working medium flowing through the sand layer; The inlet flow distribution manifold (1) is connected with the heat exchange working medium inlet pipeline, and the outlet flow distribution manifold (8) is connected with the heat exchange working medium outlet pipeline, i.e. the heat exchange working medium enters the inlet flow distribution manifold through the inlet pipeline, and then completes the heat exchange in the system. After the heat exchange is completed, the heat exchange working medium enters the outlet pipeline through the outlet distribution manifold and then leaves.

9. The layered heat storing and releasing sand tank system of claim 7, wherein, The temperature sensors and the electric valve are connected with the control module; the temperature threshold is set in the automatic control system (15), and in the actual working process, the automatic control is realized through the operation of the automatic control system (15); the control module is the execution unit of the automatic control system (15) and is used for executing the command of the automatic control system (15); The automatic control system (15) controls the electric valve according to the temperature sensor signal, so as to realize the target of heating the sand in each sand storage layer (3) layer by layer from the inlet to the outlet of the sand storage tank system.

10. The control method of the system according to any one of claims 1 to 9, characterized in that, The automatic control steps of heat storage and heat release of any sand storage layer (3) are as follows: The heat storage process of the sand storage layer X is as follows: (1) When the temperature of the temperature sensor 1T (9) in the sand storage layer X reaches the set temperature value T, at this time, it is indicated that the heating of the (X-1)th sand storage layer is completed, the electric valve one (13) is controlled to be closed, and the low-resistance passage (2) of the sand storage layer X is closed; (2) The low-resistance passage (2) is closed, the heat exchange fluid flows through the sand storage layer (3), completes the heat exchange with the sand in the sand storage layer (3), and the temperature of the sand gradually rises; (3) The heat storage amount of the sand in the sand storage layer (3) reaches the expectation, i.e. the heat storage process of the sand storage layer X is completed; at this time, the temperature of the temperature sensor 3T (11) reaches the set value T', the electric valve one (13) is controlled to be opened, and the low-resistance passage (2) of the sand storage layer X is opened; (4) The heat exchange fluid passes through the sand storage layer X through the low-resistance passage (2) and does not exchange heat with the sand, and the temperature reaches (or is higher than) the set temperature T; (5) The sand storage layer (X+1) repeats the processes (1)-(4), and the heat storage process is completed; The heat release process of the sand storage layer X is as follows: (1) When the temperature of the temperature sensor 4T (12) in the sand storage layer X reaches the set temperature value t, at this time, it is indicated that the heat release of the (X+1)th sand storage layer is completed, the electric valve two (14) is controlled to be closed, and the low-resistance passage (2) of the sand storage layer X is closed; (2) The low-resistance passage (2) is closed, the heat exchange fluid flows through the sand storage layer (3), completes the heat exchange with the sand in the sand storage layer (3), and the temperature of the sand gradually decreases; (3) The heat storage amount of the sand in the sand storage layer (3) reaches the expectation, i.e. the heat release process of the sand storage layer X is completed. At this time, the temperature of the temperature sensor 2T (10) reaches the set value t', the electric valve two (14) is controlled to be opened, and the low-resistance passage (2) of the sand storage layer X is opened; (4) The heat exchange fluid passes through the sand storage layer X through the low-resistance passage (2) and does not exchange heat with the sand, and the temperature reaches (or is lower than) the set temperature t. (5) The sand storage layer (X-1) repeats the processes (1)-(4) to complete the heat releasing process.

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