A solid-liquid hybrid heat storage / release device

Abstract

The present invention discloses a solid-liquid hybrid heat storage / release device, comprising a device body having a first inlet, a first outlet corresponding to the first inlet, a second inlet, and a second outlet corresponding to the second inlet. At any one time, only one set of inlets and outlets is in a flowing state, while the other set is in a blocked state. The device body is internally provided with a plurality of guide plates, which are used to divide the inner cavity of the device body into a plurality of flow areas, with connecting openings between the flow areas. The guide plates are provided with a solid heat storage medium, which is used to exchange heat with the liquid in the flow areas and store heat. The device of the present invention can achieve long-term heat storage, solving problems such as the intermittent nature of wind and photovoltaic power generation, and the waste of resources caused by curtailed wind and solar power.

Description

Technical Field

[0001] The present invention belongs to the field of energy storage, and in particular relates to a solid-liquid hybrid heat storage / release device. Background Art

[0002] my country's current electricity supply mainly relies on coal-fired power units, but in order to achieve the carbon neutrality goal, coal-fired power units have gradually withdrawn from the stage of history, and the proportion of renewable energy power generation (solar photovoltaic power generation, wind power generation) has been gradually increased.

[0003] However, renewable energy generation suffers from intermittent problems, preventing it from stably delivering electricity to the grid. Tower-type solar thermal power stations and molten salt energy storage technology, as components of a supporting system for wind and photovoltaic power generation, can ensure stable power output for the entire power generation system. Furthermore, the introduction of molten salt energy storage technology can avoid the waste of resources caused by curtailed wind and solar power generation, creating an "energy supply shift"—shifting renewable energy from its current generation time to meet energy demand at different times. Areas with wind or photovoltaic power generation often face climate uncertainty. Prolonged periods (more than a week) without wind or solar resources can cause the power generation system to shut down, leading to an imbalance in power supply. This can cause industrial production to stagnate due to insufficient power, resulting in significant economic losses.

[0004] Currently, existing molten salt energy storage technologies typically store energy for less than 24 hours, with no demonstration projects lasting longer than a week. Therefore, the design and research of long-term energy storage devices is of great engineering value. Summary of the Invention

[0005] Based on the above technical problems, the present invention provides a solid-liquid hybrid heat storage / release device that can store heat for a long time and solve problems such as intermittent wind and photovoltaic power generation, and waste of resources caused by wind and solar power abandonment.

[0006] To achieve the above object, the technical solution of the present invention is:

[0007] A solid-liquid hybrid heat storage / release device, comprising a device body,

[0008] The device body has a first inlet, a first outlet corresponding to the first inlet, a second inlet, and a second outlet corresponding to the second inlet, and during the same working time, only one set of the inlets and outlets is in an open state while the other set of the inlets and outlets is in a closed state;

[0009] A plurality of guide plates are arranged inside the device body, and the guide plates are used to divide the inner cavity of the device body into a plurality of flow areas, and there are connecting openings between the flow areas; a solid heat storage medium is provided on the guide plates, and the solid heat storage medium is used to exchange heat with the liquid in the flow areas and store heat.

[0010] In one embodiment of the present invention, within the same circulation area, along the liquid flow direction, some or all of the solid heat storage media are located at different heights.

[0011] In one embodiment of the present invention, in the same flow area, along the flow direction of the liquid, part or all of the solid heat storage medium is arranged in a staggered manner on the guide plate.

[0012] In one embodiment of the present invention, a plurality of spaced storage seats are provided on the guide plate, and the solid heat storage medium is provided on the storage seats.

[0013] In one embodiment of the present invention, a magnetic attraction portion is provided on the storage seat, and the solid heat storage medium is a magnetically conductive material and is adsorbed and fixed on the storage seat by the magnetic attraction portion.

[0014] In one embodiment of the present invention, the solid heat storage medium is metal waste with low cost.

[0015] In one embodiment of the present invention, a leakage hole is provided on the guide plate.

[0016] In one embodiment of the present invention, the caliber of the leakage hole gradually increases from top to bottom.

[0017] In one embodiment of the present invention, the guide baffle has a fixed end connected to the inner wall of one side of the device body and a free end spaced from the inner wall of the other side of the device body to form the connecting port; between adjacent guide plates, the fixed end of one and the free end of the other are opposite to each other in vertical direction.

[0018] In one embodiment of the present invention, the free end of the guide plate has a downwardly extending drainage portion, and the communication port is formed between the drainage portion and the inner wall of the device body.

[0019] In one embodiment of the present invention, the first inlet and the second outlet are both communicated with the flow area at the top layer, and the first outlet and the second inlet are both communicated with the flow area at the bottom layer.

[0020] In one embodiment of the present invention, the first inlet and / or the second inlet are not directly facing the solid heat storage medium and / or the storage seat.

[0021] In one embodiment of the present invention, Tesla valves are installed at the first inlet, the first outlet, the second inlet and the second outlet.

[0022] Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the prior art:

[0023] In one embodiment of the present invention, a plurality of guide plates are provided within the device body. The guide plates divide the inner cavity of the device body into a plurality of flow areas. A solid heat storage medium is placed on the guide plates. During the flow of the liquid, in each flow area, it exchanges heat with the solid heat storage medium on the guide plates and flows into the next flow area through the connecting port. The solid heat storage medium exchanges heat with the high-temperature liquid, storing the heat in the solid heat storage medium, thus realizing the heat storage function; the solid heat storage medium after heat storage exchanges heat with the low-temperature liquid, transferring the heat to the low-temperature liquid, thus realizing the heat release function. The device body realizes the functions of a thermal energy storage device and heat exchange, and adopts a mode of liquid heat absorption and solid heat storage. The liquid and solid exchange heat, and the convective heat transfer performance is improved. The heat storage / release device of the present invention can solve the problem of exchanging heat from high-temperature molten salt to the solid heat storage medium for storage, realizing long-term storage. At the same time, the electrical energy that cannot be used for power output by wind power and photovoltaic power generation can also be stored in the solid heat storage medium.

[0024] In another embodiment of the present invention, the solid heat storage medium is placed at different heights on the guide plate. This arrangement of the solid heat storage medium at different heights facilitates the formation of wavy flow in the liquid. Furthermore, the solid heat storage medium at the lower position forms a groove with a height difference with the solid heat storage medium at the higher position, which facilitates the formation of a vortex structure. Therefore, the coexistence of wavy flow and vortex flow facilitates the mixing of the liquid and the solid heat storage medium and enhances the degree of turbulence, thereby improving the convective heat transfer coefficient and enhancing the heat transfer efficiency. Within the same flow area, along the direction of liquid flow, preferably, some or all of the solid heat storage medium is arranged in a staggered arrangement on the guide plate.

[0025] In another embodiment of the present invention, a leak hole is provided on the guide plate. After the liquid exchanges heat with the solid heat storage medium, the liquid on the guide plate is promptly transferred to the next flow area for heat exchange, and ultimately flows to the bottom of the device body. This ensures that after the main device completes the heat storage / exchange process, a gaseous environment is formed in the flow area, which reduces heat transfer, enhances thermal insulation, and maintains a relatively stable temperature condition for the solid heat storage medium. The diameter of the leak hole increases from top to bottom. This facilitates the gradual increase of the flow cross-section during the top-down liquid discharge process, allowing the liquid to descend smoothly and avoiding the formation of a high-pressure jet state. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the solid-liquid hybrid heat storage / release device of this embodiment;

[0027] Figure 2 Schematic diagram of the vortex structure formed in the heat exchange zone in this embodiment;

[0028] Figure 3 This is an enlarged view of the structure of the leakage hole in the guide plate in this embodiment.

[0029] Explanation of the reference numerals: 1-first inlet; 2-first outlet; 3-second inlet; 4-second outlet; 5-movable gear valve; 6-buffer zone; 7-first heat exchange zone; 8-second heat exchange zone; 9-third heat exchange zone; 10-metal scrap; 11-magnetic portion; 12 storage seat; 13-first guide plate; 1301-fixed end of the first guide plate; 1302-free end of the first guide plate; 1303-drainage portion of the first guide plate; 14-second guide plate; 1401-fixed end of the second guide plate; 1402-free end of the second guide plate; 15-third guide plate; 16-device body; 17-vortex; 18-wavy flow; 19-leakage hole; 20-first inlet Tesla valve; 21-first outlet Tesla valve; 22-second inlet Tesla valve; 23-second outlet Tesla valve; 24-connecting port. DETAILED DESCRIPTION

[0030] The following is a further detailed description of a solid-liquid hybrid heat storage / release device proposed by the present invention in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description.

[0031] In existing solar thermal power generation technology, solar energy is first converted into thermal energy and stored, and then the stored thermal energy is converted into electrical energy and transmitted to the power grid. Currently, the most widely used solar thermal power generation technology is liquid salt (i.e., molten salt) energy storage technology. Due to the intermittent nature of renewable energy power generation (wind power generation, photovoltaic power generation) systems, solar thermal power generation technology and molten salt energy storage technology can be used as supporting system components of wind power and photovoltaic power generation to ensure stable power output of the entire power generation system. That is, the electrical energy generated by renewable energy is converted into thermal energy for storage. On the one hand, this can avoid the waste of resources caused by curtailment of wind and solar power, and on the other hand, it can achieve stable power output.

[0032] In the existing molten salt (liquid salt) energy storage technology, two molten salt tanks are required: a hot salt tank and a cold salt tank, which respectively hold the molten salt with a high temperature after heat storage and the molten salt with a low temperature after heat release. However, if heat is to be stored for a long time, such as a week, a large amount of molten salt is needed to store the heat converted from solar energy during this week. In this case, the volume of the two molten salt tanks must be very large to store a large amount of molten salt. This will bring about cost and technical difficulties. On the one hand, the cost of molten salt itself is relatively high. If long-term storage is required, more molten salt is required, which is even more expensive. On the other hand, the volume of the molten salt tank required to store molten salt is very large. Current technology makes it difficult to build a large molten salt tank. In addition, the cost of building a molten salt tank that is currently in normal use is very high. If a larger volume molten salt tank is built, the cost will be even higher.

[0033] Based on the above reasons, it is a feasible technical route to redesign the heat storage device based on the existing solar thermal power station and molten salt energy storage system to meet the demand for long-term energy storage. Therefore, the present invention uses a low-cost solid heat storage medium to store heat and proposes a device that can both store heat and exchange heat, namely a solid-liquid hybrid storage / release device, see Figure 1 The solid-liquid hybrid heat storage / release device includes a device body 16, which has a first inlet 1, a first outlet 2 corresponding to the first inlet 1, a second inlet 3 and a second outlet 4 corresponding to the second inlet 3. During the same working time, only one group of inlets and outlets is in an open state and the other group of inlets and outlets is in a closed state. The working time refers to the time corresponding to heat storage or heat release.

[0034] The device body 16 is internally provided with several deflectors, which divide the internal cavity into several flow zones. Connecting openings 24 are located between these zones. A solid heat storage medium is located on the deflectors, exchanging heat with the liquid in the flow zones and storing heat. In this embodiment, the first inlet 1 and the second outlet 4 both communicate with the flow zones on the top layer, while the first outlet 2 and the second inlet 3 both communicate with the flow zones on the bottom layer. Within the device body, in different heat storage and heat release modes, liquid can flow into the device body from the first inlet 1 and out from the first outlet 2, or from the second inlet 3 and out from the second outlet 4. In this embodiment, in the heat storage mode, liquid flows into the device body from the upper first inlet 1 and out from the lower first outlet 2. In the heat release mode, liquid flows into the device body from the lower second inlet 3 and out from the upper second outlet 4. To prevent liquid from impacting the solid heat storage medium, the first inlet 1 and the second inlet 3 can be positioned away from the solid heat storage medium.

[0035] Several guide plates are provided in the device body 16, and solid heat storage medium is placed on the guide plates. Figure 1In this embodiment, three guide plates are provided in the device body 16. The three guide plates divide the device body into four circulation areas. For the molten salt entering / exiting the device body, in order to make the flow rate of the liquid molten salt smooth as a whole and avoid the sudden expansion or contraction of the molten salt flow rate, which causes pipeline oscillation due to the sudden change in flow rate, no solid heat storage medium is provided in the circulation area at the bottom layer, thereby forming an expansion and pressure reduction area, and the area with solid heat storage medium is the heat exchange area. That is, in the direction of liquid flow from top to bottom, the guide plates include a first guide plate 13, a second guide plate 14 and a third guide plate 15. The space between the first guide plate 13 and the top of the device body 16 is the first heat exchange area 7, the area between the upper part of the second guide plate 14 and the lower part of the first guide plate 13 is the second heat exchange area 8, the area between the upper part of the third guide plate 15 and the lower part of the second guide plate 14 is the third heat exchange area 9, and the area between the lower part of the third guide plate 15 and the bottom of the device body 16 is the buffer area 6. Each heat exchange zone and the heat exchange zone and the buffer zone are connected through the connecting port 24. The liquid molten salt exchanges heat with the solid heat storage medium in each heat exchange zone. When the liquid molten salt enters / exhausts the device body 16 in the buffer zone 6 (in the heat storage state, the liquid molten salt exits the device body 16 in the buffer zone 6; in the heat release state, the liquid molten salt enters the device body 16 in the buffer zone 6), an expansion and pressure reduction area can be formed, so that the flow rate of the liquid molten salt is overall smooth, avoiding pipeline vibration caused by sudden changes in flow rate due to sudden expansion and contraction of the molten salt.

[0036] The structure of each guide plate is the same. Taking the first guide plate and the second guide plate as an example, the communication opening 24 formed between adjacent guide plates is specifically described. Figure 1 The first deflector plate 13 has a fixed end 1301 connected to one inner wall of the device body 16 and a free end 1302 spaced apart from the other inner wall of the device body 16 to form a communication opening 24. Between the first deflector plate 13 and the second deflector plate 14, the fixed end 1301 of the first deflector plate 13 and the free end 1402 of the second deflector plate 14 face the communication opening 24 formed in the inner wall of the device body 16, while the free end 1302 of the first deflector plate 13 faces the communication opening 24 formed in the inner wall of the device body 16 and the fixed end 1401 of the second deflector plate 14. A drainage portion 1303 extends downward from the free end 1302 of the first deflector plate 13, forming a communication opening 24 with the inner wall of the device body 16.

[0037] As high-temperature liquid molten salt flows downward from the top of the device body 16, it sequentially passes through the first heat exchange zone 7, the second heat exchange zone 8, and the third heat exchange zone 9, transferring heat to the solid heat storage medium in each heat exchange zone and storing the heat in the solid heat storage medium. Low-temperature liquid molten salt enters the device body 16 from the bottom, passes through the guide plate, and passes through each heat exchange zone, absorbing the heat stored in the solid heat storage medium. The low-temperature liquid molten salt is converted into high-temperature liquid molten salt and flows out of the device body 16 through the first outlet 2 at the top. Exchanging the heat of the liquid molten salt for storage in the cheaper solid heat storage medium greatly reduces costs, especially the cost of building a storage tank for the heat storage medium, which is much lower than that of a molten salt tank, and can store heat for a long time. Electricity generated by abandoned wind and solar power is converted into thermal energy and stored. During peak hours or when there is no wind or solar power for a long time, the stored thermal energy is converted into electrical energy and fed into the power grid. Alternatively, unstable renewable energy generation is converted into thermal energy for storage, and the thermal energy is then converted into stable electrical energy for output to the power grid.

[0038] At the same time, the device realizes the functions of thermal energy storage and heat exchange, and adopts the mode of liquid heat absorption and solid heat storage. The liquid and solid exchange heat, and the convective heat transfer performance is improved.

[0039] In this embodiment, the solid heat storage medium is a cheaper metal scrap 10, which can be solid steel slag, mechanical scrap iron, stamping iron scrap, motor iron and other metal scraps. The metal scrap 10 is generally treated as waste in the steelmaking industry. In this embodiment, it is used as a solid heat storage medium to store heat, which greatly reduces the cost compared to molten salt and can store heat for a long time. When there is no wind or light resource for a long time, the heat stored in the metal scrap 10 in the device body 16 is exchanged with the low-temperature molten salt to make it become high-temperature molten salt, and the high-temperature molten salt enters the next process of the solar thermal power station.

[0040] See Figure 2 In another embodiment, in the same heat exchange zone, part or all of the metal scraps 10 are located at different heights along the flow direction of the molten salt liquid.

[0041] Arranging the scrap metal 10 in the same heat exchange zone at different heights facilitates the formation of wavy flows 18 in the liquid molten salt. Furthermore, the height difference between the scrap metal 10 at higher heights and the scrap metal 10 at lower heights creates grooves that facilitate the formation of eddy currents 17. The coexistence of wavy flows 18 and eddy currents 17 facilitates the mixing of the molten salt and the scrap metal 10, enhances the degree of turbulence, and improves the convective heat transfer coefficient and heat exchange efficiency. Preferably, some or all of the solid heat storage medium is arranged in a staggered arrangement on the guide plate.

[0042] In this embodiment, the metal scrap 10 is placed on a storage seat 12, and a through hole can be opened on the storage seat 12. The heights of the metal scrap 10 are different, that is, the storage seat 12 is arranged at intervals on the guide plate and at different heights. Of course, other forms of storing the metal scrap 10 can also be used, such as a support, or an installation groove directly opened on the guide plate.

[0043] To prevent the liquid molten salt from carrying away the metal scrap 10 during its flow, a magnetic attraction portion 11 is provided on the storage seat 12. The metal scrap 10 is fixed to the storage seat 12 by adsorption of the magnetic attraction portion 11. The provision of the magnetic attraction portion 11 facilitates the adsorption of the metal scrap 10, preventing the liquid molten salt from carrying away the metal scrap 10 and entering the pipeline system during the heat exchange process between the liquid molten salt and the metal scrap 10, and is convenient to install. In this embodiment, the solid heat storage medium is a magnetic material such as the metal scrap 10. If it is a non-magnetic solid heat storage medium, other connecting parts can be used to fix the solid heat storage medium to the guide plate or the storage seat, such as using steel bars, screws, or directly opening a mounting groove on the guide plate to prevent the liquid from carrying away the solid heat storage medium.

[0044] In another embodiment, multiple small leak holes 19 are provided on the guide plate. After the liquid molten salt exchanges heat with the solid heat storage medium, the liquid molten salt on the guide plate is promptly transferred to the next heat exchange zone for heat exchange, and ultimately flows to the bottom of the device body 16. This facilitates the formation of a gaseous environment in the heat exchange zone after the storage / heat exchange process is completed, effectively reducing heat transfer, enhancing thermal insulation, and maintaining the solid heat storage medium at a relatively stable temperature. For the entire device body 16, the provision of leak holes 19 allows the liquid molten salt in the device to be promptly emptied after the storage / heat exchange is completed, maintaining a gaseous environment within the device and facilitating thermal insulation.

[0045] Preferably, see Figure 3 The diameter of the leak hole 19 gradually increases from top to bottom, which helps to gradually increase the flow cross-section during the top-down drainage process, making the liquid descend more smoothly and avoiding the formation of a high-pressure jet state. Because if a high-pressure jet is formed, the flow velocity will increase and the impact force will increase. If the fluid jet hits the guide plate or storage seat 12, the guide plate or storage seat 12 will be impacted, resulting in a decrease in structural stability. In addition, the solid heat storage medium may also be impacted and flow out of the guide plate.

[0046] In another embodiment, Tesla valves are installed at the first inlet 1, the first outlet 2, the second inlet 3 and the second outlet 4 to form a first inlet Tesla valve 20, a first outlet Tesla valve 21, a second inlet Tesla valve 22 and a second outlet Tesla valve 23. The unidirectional conductivity of the Tesla valve is utilized to help avoid backflow of the molten salt pipeline.

[0047] In another embodiment, the second inlet 3 is arranged at the bottom of the device body 16, and the second outlet 4 is arranged at the bottom of the side wall of the device body 16 close to the second inlet 3. A movable baffle valve 5 is provided at the second inlet 3. When the second inlet 3 is opened, the movable baffle valve 5 closes the second outlet 4.

[0048] The working principle of the solid-liquid hybrid heat storage / release device of this embodiment is as follows:

[0049] The heat storage operation principle is as follows:

[0050] The high-temperature molten salt enters the device body 16 through the first inlet Tesla valve 20, and passes through the first heat exchange zone 7, the second heat exchange zone 8, and the third heat exchange zone 9 in sequence. In the heat exchange zone, the high-temperature molten salt heats the metal scrap 10 through immersion convection heat exchange and stores heat. After the heat exchange with the metal scrap 10 is completed, the molten salt finally reaches the buffer zone 6, flows out of the device body 16 through the second outlet Tesla valve 23, and will enter the next round of system front-end heat absorption process.

[0051] The exothermic operation principle is as follows:

[0052] The low-temperature molten salt enters the device body 16 through the second inlet Tesla valve 22, opens the shift valve, and shift valve 5 closes the passage between the second outlet Tesla valve 23 and the device body 16. It then passes through the third heat exchange zone 9, the second heat exchange zone 8, and the first heat exchange zone 7. As the low-temperature molten salt passes through the metal scrap 10 in each heat exchange zone, it absorbs heat from the scrap 10, gradually transforming the low-temperature molten salt into high-temperature molten salt. Finally, the high-temperature molten salt flows out of the device body 16 through the first outlet Tesla valve 21 and enters the subsequent power generation system. After heat release is completed, the remaining molten salt in the device body 16 is discharged through the first outlet Tesla valve 21, maintaining the atmosphere within the device body 16.

[0053] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they still fall within the scope of protection of the present invention.

Claims

1. A solid-liquid hybrid heat storage / release device, characterized in that: The device comprises a main body having a first inlet, a first outlet corresponding to the first inlet, a second inlet, and a second outlet corresponding to the second inlet, wherein only one set of the inlets and outlets is in an open state and the other set of the inlets and outlets is in a closed state during the same working time; A plurality of guide plates are provided inside the device body, and the guide plates are used to divide the inner cavity of the device body into a plurality of flow areas, and there are communication openings between the flow areas; a solid heat storage medium is provided on the guide plates, and no solid heat storage medium is provided in the flow area at the bottom of the device body. The flow area with the solid heat storage medium is a heat exchange area, and the solid heat storage medium is used to exchange heat with the liquid in the heat exchange area and store heat; In the same circulation area, along the liquid flow direction, some or all of the solid heat storage media are located at different heights; The guide plate is provided with a plurality of storage seats at intervals, and the solid heat storage medium is provided on the storage seats; a magnetic attraction portion is provided on the storage seat, and the solid heat storage medium is a magnetically conductive material and is fixed to the storage seat by adsorption through the magnetic attraction portion; The guide plate is provided with leakage holes, and the diameter of the leakage holes gradually increases from top to bottom.

2. The solid-liquid hybrid heat storage / release device according to claim 1, characterized in that: In the same circulation area, along the flow direction of the liquid, part or all of the solid heat storage medium is arranged in a staggered manner on the guide plate.

3. The solid-liquid hybrid heat storage / release device according to claim 1 or 2, characterized in that: The solid heat storage medium is metal waste.

4. The solid-liquid hybrid heat storage / release device according to claim 1, characterized in that: The guide plate has a fixed end connected to the inner wall of one side of the device body and a free end spaced from the inner wall of the other side of the device body to form the communication port; between adjacent guide plates, the fixed end of one is opposite to the communication port of the other.

5. The solid-liquid hybrid heat storage / release device according to claim 4, characterized in that: The free end of the guide plate is provided with a guide portion extending downward, and the communication port is formed between the guide portion and the inner wall of the device body.

6. The solid-liquid hybrid heat storage / release device according to claim 1, characterized in that: The first inlet and the second outlet are both communicated with the circulation area at the top layer, and the first outlet and the second inlet are both communicated with the circulation area at the bottom layer.

Images