An efficient molten salt thermal energy storage system and its usage method

Abstract

The present invention relates to an efficient molten salt heat storage system and its usage method, which can efficiently achieve the heating of a fluid. It includes a molten salt tank, an annular upper water tank, and an annular lower water tank. An auxiliary electric heating wire is installed in the annular lower water tank. The upper and lower ends of the molten salt tank are respectively connected to a molten salt inlet pipe and a molten salt outlet pipe. The annular upper water tank and the annular lower water tank are respectively connected to a water inlet pipe and a water outlet pipe. It also includes a plurality of heating pipes arranged circumferentially around the molten salt tank. The upper and lower ends of the heating pipes are respectively rotatably connected to the annular upper water tank and the annular lower water tank. Heat insulation layers and heat conducting layers are respectively attached to both sides of the heating pipes. The heating pipes are attached to the accommodating grooves on the outer side of the molten salt tank to insulate the molten salt tank. At the same time, the heat dissipated by the molten salt tank is transferred to the water in the heating pipes through the heat conducting layer to achieve the heating of the water. The water temperature in the heating pipes is adjusted by rotating the heating pipes to adjust the size of the contact surface between the heat conducting layer and the accommodating groove. Heating can also be carried out through the auxiliary electric heating wire in the annular lower water tank.

Description

Technical Field

[0001] The present invention relates to the technical field of fluid heating, and specifically refers to an efficient molten salt heat storage system and its usage method. Background Art

[0002] A molten salt heat storage system heats cold salt into liquid hot salt and stores it in a hot salt tank. The hot salt in the hot salt tank is transported to a heat exchange system through a hot molten salt pump to exchange heat with water or steam. After releasing heat, the liquid cold salt returns to the cold salt tank to complete the salt absorption, storage, and conversion cycle.

[0003] High-temperature molten salt can reach over 500 °C. As described above, the heat in the high-temperature molten salt is used to heat a fluid. This fluid can be the water used by a steam turbine generator. By heating the water, superheated steam is generated to drive the steam turbine generator to rotate and generate electricity. The fluid can also be boiler water. After heating the water in the boiler, it is used for production and living.

[0004] However, when heating boiler water, the existing technology uses a direct heat exchange method through a heat exchanger. Since the temperature of the liquid molten salt can reach over 500 °C, a large amount of water in contact with the wall of the liquid molten salt pipe will vaporize during heat exchange, generating a large amount of steam. To prevent excessive pressure, these steams must be released, so a large amount of heat will be wasted, and the temperature of the molten salt cannot be reduced. If it is too low, the molten salt will solidify and block the pipeline. Summary of the Invention

[0005] Aiming at the deficiencies of the existing technology, the present invention provides an efficient molten salt heat storage system and its usage method.

[0006] The present invention is realized through the following technical solutions. An efficient molten salt heat storage system is provided, including a molten salt tank, an annular upper water tank located above the molten salt tank, and an annular lower water tank located below the molten salt tank. An auxiliary electric heating wire is installed in the annular lower water tank. The upper and lower ends of the molten salt tank are respectively connected to a molten salt inlet pipe and a molten salt outlet pipe. The annular upper water tank and the annular lower water tank are respectively connected to a water inlet pipe and a water outlet pipe. It also includes a plurality of heating pipes arranged circumferentially around the molten salt tank. The upper and lower ends of the heating pipes are respectively rotatably connected to the annular upper water tank and the annular lower water tank. Heat insulation layers and heat conduction layers are respectively attached to both sides of the heating pipes. A receiving groove for accommodating the heating pipes is provided outside the molten salt tank. The temperature of the water in the heating pipes is adjusted by rotating the heating pipes to adjust the size of the contact surface between the heat conduction layer and the receiving groove.

[0007] As an optimization, an upper slewing bearing is installed on the lower end surface of the annular upper water tank, and a lower slewing bearing is installed on the upper end surface of the annular lower water tank. Upper connecting gears and lower connecting gears are respectively fixed at the upper and lower ends of the heating pipes. The upper connecting gear meshes with the rotating ring of the upper slewing bearing, and the lower connecting gear meshes with the rotating ring of the lower slewing bearing. A driving motor for driving the rotating ring of the upper slewing bearing to rotate is installed on the annular upper water tank.

[0008] As an optimization, it further includes an outer heat insulation cover wrapping the molten salt tank. The heating tubes are located inside the outer heat insulation cover, and a heat insulation filling layer is provided inside the outer heat insulation cover.

[0009] As an optimization, the upper end of the heating tube is provided with an upper convex edge located inside the annular upper water tank. A sealing gasket is installed between the upper convex edge and the inner wall of the annular upper water tank. The lower end of the heating tube is provided with a lower convex edge located inside the annular lower water tank. A sealing gasket is installed between the lower convex edge and the inner wall of the annular lower water tank. The pressing and sealing at both ends of the heating tube are achieved through the weight of the annular lower water tank.

[0010] As an optimization, a plurality of circumferentially arranged elastic support mechanisms are installed at the lower end of the annular lower water tank. The elastic support mechanism includes a base fixed on the ground, an upper support seat fixedly connected to the lower end face of the annular lower water tank, and a lower support seat located below the upper support seat. A spring is installed between the lower support seat and the upper support seat. A screw rod passing through the lower support seat is fixedly connected to the base. The height of the lower support seat is adjusted by adjusting the position of the adjusting nut on the screw rod, so as to adjust the supporting force exerted by the spring on the annular lower water tank.

[0011] As an optimization, the water inlet pipe passes through the condensation tank. One end of the condensation tank is communicated with the annular upper water tank through a steam discharge pipe. The other end of the condensation tank is provided with an upward exhaust port and a downward drain port.

[0012] As an optimization, it further includes a pressing mechanism that presses the middle parts of all the heating tubes in the receiving groove, and the pressing mechanism releases when the heating tubes rotate.

[0013] As an optimization, the pressing mechanism includes a fixed ring fixedly connected to the outside of the molten salt tank, a floating ring sleeved on the outer ring of the fixed ring, and a cylinder for driving the floating ring to move up and down. A pressing plate is provided between the heating tube and the fixed ring. A top rod passing through the outer ring of the fixed ring is fixedly connected to the pressing plate. A pressing inclined surface is provided on the inner ring of the floating ring.

[0014] As an optimization, a circulation pipe is communicated between the molten salt inlet pipe and the molten salt outlet pipe, and a circulation pump is installed on the circulation pipe.

[0015] A method for using an efficient molten salt heat storage system includes the following steps:

[0016] a. High-temperature liquid molten salt enters the molten salt tank through the molten salt inlet pipe to achieve heat storage;

[0017] b. Water enters the annular upper water tank through the water inlet pipe, flows through a plurality of heating tubes to the annular lower water tank, and finally flows out through the water outlet pipe.

[0018] c. The heating tube is fitted in the receiving groove on the outer side of the molten salt tank to insulate the molten salt tank. At the same time, the heat dissipated by the molten salt tank is transferred to the water in the heating tube through the heat conduction layer to heat the water. The water temperature in the heating tube is adjusted by rotating the heating tube to adjust the contact area between the heat conduction layer and the receiving groove;

[0019] d. When the contact area between the heat conduction layer and the receiving groove is in the maximum state and the water temperature does not meet the requirements, heating is carried out through the auxiliary heating wire in the annular lower water tank.

[0020] The beneficial effects of the present invention are as follows: For an efficient molten salt heat storage system and its usage method of the present invention, water enters the annular upper water tank through the water inlet pipe, flows through multiple heating tubes to the annular lower water tank, and finally flows out through the water outlet pipe. The heating tube is fitted in the receiving groove on the outer side of the molten salt tank to insulate the molten salt tank. At the same time, the heat dissipated by the molten salt tank is transferred to the water in the heating tube through the heat conduction layer to heat the water. The water temperature in the heating tube is adjusted by rotating the heating tube to adjust the contact area between the heat conduction layer and the receiving groove. When the contact area between the heat conduction layer and the receiving groove is in the maximum state and the water temperature does not meet the requirements, heating is carried out through the auxiliary heating wire in the annular lower water tank, thereby realizing the heating of water.

[0021] The present invention realizes the heating of water on the outer side of the molten salt tank. On the one hand, the heat transfer temperature is low, the high-temperature vaporization phenomenon of water is less, and the outer area of the molten salt tank is large, which can realize the heating of a large flow of water. On the other hand, the heat preservation function of the molten salt tank can be realized at the same time, improving the heat preservation effect. Description of the Drawings

[0022] Figure 1 is a schematic structural diagram of the present invention;

[0023] Figure 2 is a schematic structural diagram of the present invention from another angle;

[0024] Figure 3 is a front view of the present invention;

[0025] Figure 4 is the present invention Figure 3 A - A sectional view;

[0026] Figure 5 is a schematic structural diagram of the molten salt tank of the present invention; [[ID=3 cinco]]

[0027] Figure 6 is a front view of the molten salt tank of the present invention;

[0028] Figure 7 is the present invention Figure 6 C - C sectional view;

[0029] Figure 8 is a front view of the heating tube of the present invention;

[0030] Figure 9 Cross-sectional schematic diagram of the heating tube of the present invention;

[0031] Figure 10 For the present invention Figure 8 Cross-sectional view taken along the D-D plane of the present invention;

[0032] Figure 11 Structural schematic diagram of the annular lower water tank and a single heating tube of the present invention;

[0033] Figure 12 Structural schematic diagram of the annular upper water tank and a single heating tube of the present invention;

[0034] Figure 13 Cross-sectional view of the elastic support mechanism of the present invention;

[0035] Figure 14 Structural schematic diagram of the pressing mechanism of the present invention;

[0036] Figure 15 For the present invention Figure 3 Cross-sectional view taken along the B-B plane of the present invention;

[0037] Figure 16 For the present invention Figure 15 Cross-sectional view taken along the E-E plane of the present invention;

[0038] As shown in the figure:

[0039] 1. Annular upper water tank, 2. Molten salt tank, 3. Annular lower water tank, 4. Heating tube, 41. Heat insulation layer, 42. Heat conduction layer, 43. Upper connecting gear, 44. Lower connecting gear, 45. Upper convex edge, 46. Lower convex edge, 47. Sealing gasket, 5. Pressing mechanism, 51. Fixed ring, 52. Floating ring, 53. Pressing plate, 54. Jack rod, 55. Cylinder, 6. Molten salt inlet pipe, 7. Molten salt outlet pipe, 8. Water inlet pipe, 9. Water outlet pipe, 10. Steam discharge pipe, 11. Condensation tank, 12. Exhaust port, 13. Drain port, 14. Leg, 15. Elastic support mechanism, 151. Spring, 152. Upper support seat, 153. Lower support seat, 154. Base, 155. Screw rod, 156. Adjusting nut, 16. Circulation pipe, 17. Lower slewing bearing, 18. Upper slewing bearing, 19. Driving gear, 20. Driving motor, 21. Outer thermal insulation cover, 22. Thermal insulation filling layer. Detailed implementation manners

[0040] To clearly illustrate the technical features of this solution, the following elaborates on this solution through specific implementation manners.

[0041] As Figures 1 to 16 shown, an efficient molten salt heat storage system of the present invention includes a molten salt tank 2, an annular upper water tank 1 located above the molten salt tank 2, and an annular lower water tank 3 located below the molten salt tank 2.

[0042] The molten salt tank 2 is a vertical cylindrical tank, which is hermetically arranged. The upper and lower ends of the molten salt tank 2 are respectively connected to the molten salt inlet pipe 6 and the molten salt outlet pipe 7. High-temperature molten salt enters the molten salt tank 2 through the molten salt inlet pipe 6 for storage. When heating is required, the molten salt is discharged through the molten salt outlet pipe 7. The molten salt tank 2 is supported on the ground by four legs 14.

[0043] Since heating pipes need to be arranged outside the molten salt tank 2 in this application, the molten salt inlet pipe 6 and the molten salt outlet pipe 7 can only be connected to the upper and lower end faces of the molten salt tank 2. The annular upper water tank 1 is annular, and the middle circular hole facilitates the passing of the molten salt inlet pipe 6. The annular lower water tank 3 is annular and the middle circular hole facilitates the passing of the molten salt outlet pipe 7 and the legs 14.

[0044] The annular upper water tank 1 and the annular lower water tank 3 are respectively connected to the water inlet pipe 8 and the water outlet pipe 9. In this embodiment, the water inlet pipe 8 is horizontally connected to the side of the annular upper water tank 1, and the water outlet pipe 9 is horizontally connected to the side of the annular lower water tank 3.

[0045] It also includes a plurality of heating pipes 4 arranged circumferentially along the molten salt tank 2. The heating pipes 4 are vertical circular pipes. The upper and lower ends of the heating pipes 4 are respectively rotationally connected to the annular upper water tank 1 and the annular lower water tank 3. For the specific structure, refer to Figure 10 , the upper end of the heating pipe 4 penetrates into the lower end of the annular upper water tank 1 and an O-ring for sealing is installed in the penetration hole. The lower end of the heating pipe 4 penetrates into the upper end of the annular lower water tank 3 and an O-ring for sealing is installed in the penetration hole.

[0046] The upper end of the heating pipe 4 is provided with an upper convex edge 45 located in the annular upper water tank 1, and a sealing gasket 47 is installed between the upper convex edge 45 and the inner wall of the annular upper water tank 1. The lower end of the heating pipe 4 is provided with a lower convex edge 46 located in the annular lower water tank 3, and a sealing gasket is installed between the lower convex edge 46 and the inner wall of the annular lower water tank 3. In this embodiment, the annular lower water tank 3 does not have a fixed support structure, so its weight is supported by hanging through the heating pipes 4. Therefore, the pressing and sealing at both ends of the heating pipes 4 are realized by the weight of the annular lower water tank 3.

[0047] Since the weight of the annular lower water tank 3 is too large, it is easy to cause the sealing gasket 47 to be overly compressed, and it is also not conducive to the rotation of the heating pipes 4. Therefore, a plurality of elastic support mechanisms 15 arranged circumferentially are installed at the lower end of the annular lower water tank 3 to offset part of the weight.

[0048] The elastic support mechanism 15 includes a base 154 fixed to the ground, an upper support seat 152 fixedly connected to the lower end face of the annular lower water tank 3, and a lower support seat 153 located below the upper support seat 152. A spring 151 is installed between the lower support seat 153 and the upper support seat 152. A screw 155 passing through the lower support seat 153 is fixedly connected to the base 154. The height of the lower support seat 153 is adjusted by adjusting the position of the adjusting nut 156 on the screw 155, so as to adjust the supporting force exerted by the spring 151 on the annular lower water tank 3.

[0049] As Figure 9 shown, heat insulation layers 41 and heat conduction layers 42 are respectively attached to both sides of the heating pipe 4. The heat insulation layer 41 plays a role in heat insulation, and the heat conduction layer 42 plays a role in heat conduction. Both the heat insulation layer 41 and the heat conduction layer 42 are semi-circular plates, and a cylindrical structure is formed by the outer circles of the heat insulation layer 41 and the heat conduction layer 42.

[0050] An accommodation groove for accommodating the heating pipe 4 is provided outside the molten salt tank 2. The accommodation groove is an arc-shaped groove and the cross-sections at all positions from top to bottom are the same. The central angle of the arc is between 70 - 90 degrees, so as to wrap about half or nearly half of the heating pipe 4. As Figures 5 to 7 shown, the accommodation grooves are densely arranged, so that most of the outer circle area of the molten salt tank 2 is wrapped by the heating pipe 4.

[0051] By rotating the heating pipe 4, the contact area between the heat conduction layer 42 and the accommodation groove is adjusted to adjust the water temperature in the heating pipe 4. When the accommodation groove is all filled with the heat conduction layer 42, the heating effect on the heating pipe is the best at this time. When the accommodation groove is all filled with the heat insulation layer 41, the heating effect on the heating pipe is the worst, and the heat preservation effect on the molten salt tank 2 is the best.

[0052] It further includes an outer heat preservation cover 21 wrapping the molten salt tank 2. The heating pipe 4 is located inside the outer heat preservation cover 21, and a heat preservation filling layer 22 is provided inside the outer heat preservation cover 21 to prevent heat dissipation. For the convenience of observation, in the drawings of the present application, only Figure 4 shows the heat preservation cover 21 and the heat preservation filling layer 22.

[0053] To realize the synchronous rotation of all the heating pipes, an upper slewing bearing 18 is installed on the lower end face of the annular upper water tank 1, and a lower slewing bearing 17 is installed on the upper end face of the annular lower water tank 3. All the heating pipes 4 are located inside the inner rings of the upper slewing bearing 18 and the lower slewing bearing 17. Upper connecting gears 43 and lower connecting gears 44 are respectively fixedly connected to the upper and lower ends of the heating pipe 4. For the convenience of arranging the upper connecting gears 43 and the lower connecting gears 44, as Figure 5 、 6 shown, parts with reduced diameters are provided at the upper and lower ends of the molten salt tank 2 to avoid the upper connecting gears 43 and the lower connecting gears 44.

[0054] The upper connecting gear 43 meshes with the rotating ring of the upper slewing bearing 18, so that all the upper connecting gears 43 are rotated by the rotation of the rotating ring of the slewing bearing 18, thereby driving all the heating tubes 4 to rotate. A driving motor 20 for driving the rotating ring of the upper slewing bearing 18 to rotate is installed on the annular upper water tank 1. The driving motor 20 drives the driving gear 19 to rotate. External teeth are provided on the outer ring of the rotating ring of the upper slewing bearing 18, and the driving gear 19 meshes with the external teeth, thereby realizing the rotation of the rotating ring of the upper slewing bearing 18.

[0055] The lower connecting gear 44 meshes with the rotating ring of the lower slewing bearing 17, so that all the lower connecting gears 44 are synchronously rotated through the rotating ring of the lower slewing bearing 17, and thus the synchronous rotation of the lower ends of all the heating tubes is realized, preventing the distortion caused by the jamming of a single heating tube.

[0056] Since both the lower connecting gear 44 and the upper connecting gear 43 are spur gears, the up-and-down floating of the annular lower water tank 3 is not affected.

[0057] As the heating tubes heat up, the temperature of the molten salt at the inner edge of the molten salt tank 2 decreases. To improve the heating effect, a circulation pipe 16 is connected between the molten salt inlet pipe 6 and the molten salt outlet pipe 7, and a circulation pump is installed on the circulation pipe 16. By turning on the circulation pump, the molten salt at the bottom of the molten salt tank 2 can be pumped into the top of the molten salt tank 2, so that the molten salt flows inside, increasing the temperature at the edge position.

[0058] Auxiliary electric heating wires are installed in the annular lower water tank 3. When the contact area between the heat conduction layer and the receiving groove is in the maximum state and the water temperature does not meet the requirements, heating is carried out through the auxiliary electric heating wires in the annular lower water tank.

[0059] During the heating process of this application, steam is inevitably generated. A condensation tank 11 is provided in this application. The water inlet pipe 8 passes through the condensation tank 11. One end of the condensation tank 11 is communicated with the annular upper water tank 1 through a steam discharge pipe 10. The other end of the condensation tank 11 is provided with an upward exhaust port 12 and a downward drain port 13. After the steam enters the condensation tank 11 for condensation, the gas is discharged through the exhaust port 12, and the condensed water is discharged through the drain port 13. When condensing, the water in the water inlet pipe 8 is heated, improving the utilization rate of heat.

[0060] Since the heating tubes are relatively long, the middle position is prone to bending and deformation, so that it cannot be closely attached to the receiving groove, and thus a good heat exchange effect cannot be achieved. Therefore, this application further includes a pressing mechanism 5 for pressing the middle parts of all the heating tubes 4 in the receiving groove, and the pressing mechanism 5 is released when the heating tubes 4 rotate.

[0061] As Figures 14 to 16As shown, the pressing mechanism 5 includes a fixed ring 51 fixedly connected to the outside of the molten salt tank 2, a floating ring 52 sleeved on the outer ring of the fixed ring 51, and a cylinder 55 for driving the floating ring 52 to move up and down. The fixed ring 51 is fixed on the outer wall of the molten salt tank 2 between adjacent heating tubes, and an arc-shaped avoidance groove for avoiding the heating tubes is formed on the fixed ring 51.

[0062] A pressing plate 53 is provided between the heating tube 4 and the fixed ring 51. Each heating tube 4 corresponds to a pressing plate 53. The pressing plate 53 is an arc-shaped plate. A top rod 54 passing through the outer ring of the fixed ring 51 is fixedly connected to the pressing plate 53, and the end of the top rod 54 is spherical.

[0063] As Figure 16 shown, a pressing inclined surface is provided on the inner ring of the floating ring 52 in this application. By moving the floating ring 52 downward, the top rod 54 is pressed inward, realizing the pressing of the heating tube 4 by the pressing plate 53. As Figure 14 shown, two cylinders 55 are provided and symmetrically arranged. The cylinders are fixed on the outside of the fixed ring 51, and the telescopic shafts of the cylinders are connected to the floating ring 52.

[0064] A usage method of an efficient molten salt heat storage system includes the following steps:

[0065] a. High-temperature liquid molten salt enters the molten salt tank 2 through the molten salt inlet pipe 6 to realize heat storage;

[0066] b. Water enters the annular upper water tank 1 through the water inlet pipe 8, flows through a plurality of heating tubes 4 to the annular lower water tank 3, and finally flows out through the water outlet pipe 9;

[0067] c. The heating tube 4 is attached to the accommodation groove on the outside of the molten salt tank 2 to keep the molten salt tank 2 warm. At the same time, the heat dissipated by the molten salt tank 2 is transferred to the water in the heating tube 4 through the heat conduction layer 42 to realize the heating of the water. The water temperature in the heating tube 4 is adjusted by rotating the heating tube 4 to adjust the contact area between the heat conduction layer 42 and the accommodation groove;

[0068] d. When the contact area between the heat conduction layer 42 and the accommodation groove is in the maximum state and the water temperature does not meet the requirements, heating is carried out through the auxiliary electric heating wire in the annular lower water tank 3.

[0069] Of course, the above description is not limited to the above examples. The technical features not described in the present invention can be realized by or adopted the existing technology, and will not be elaborated here; the above embodiments and drawings are only used to illustrate the technical solutions of the present invention and are not limitations to the present invention. The present invention has been described in detail with reference to the preferred embodiments. Those of ordinary skill in the art should understand that the changes, modifications, additions or substitutions made by those of ordinary skill in the art within the scope of the essence of the present invention do not depart from the purpose of the present invention and should also belong to the protection scope of the claims of the present invention.

Claims

1. An efficient molten salt thermal energy storage system, characterized in that: It includes a molten salt tank (2), an annular upper water tank (1) located above the molten salt tank (2), and an annular lower water tank (3) located below the molten salt tank (2). An auxiliary electric heating wire is installed in the annular lower water tank (3). The upper and lower ends of the molten salt tank (2) are respectively connected to a molten salt inlet pipe (6) and a molten salt outlet pipe (7). The annular upper water tank (1) and the annular lower water tank (3) are respectively connected to a water inlet pipe (8) and a water outlet pipe (9). It also includes a plurality of heating pipes (4) arranged circumferentially along the molten salt tank (2). The upper and lower ends of the heating pipe (4) are respectively rotatably connected to the annular upper water tank (1) and the annular lower water tank (3). Heat insulation layers (41) and heat conduction layers (42) are respectively attached to both sides of the heating pipe (4). The heat insulation layer and the heat conduction layer are both semi-circular plates, and a cylindrical structure is formed by the outer circles of the heat insulation layer and the heat conduction layer; A receiving groove for receiving the heating pipe (4) is provided on the outer side of the molten salt tank (2). The contact area between the heat conduction layer (42) and the receiving groove is adjusted by rotating the heating pipe (4) to adjust the water temperature in the heating pipe (4); An upper convex edge (45) located in the annular upper water tank (1) is provided at the upper end of the heating pipe (4). A sealing gasket is installed between the upper convex edge (45) and the inner wall of the annular upper water tank (1). A lower convex edge (46) located in the annular lower water tank (3) is provided at the lower end of the heating pipe (4). A sealing gasket is installed between the lower convex edge (46) and the inner wall of the annular lower water tank (3). The two ends of the heating pipe (4) are tightly sealed by the weight of the annular lower water tank (3); A plurality of elastic support mechanisms (15) arranged circumferentially are installed at the lower end of the annular lower water tank (3). The elastic support mechanism (15) includes a base (154) fixed on the ground, an upper support seat (152) fixedly connected to the lower end face of the annular lower water tank (3), and a lower support seat (153) located below the upper support seat (152). A spring (151) is installed between the lower support seat (153) and the upper support seat (152). A screw rod (155) passing through the lower support seat (153) is fixedly connected to the base (154). The height of the lower support seat (153) is adjusted by adjusting the position of the adjusting nut (156) on the screw rod (155), so as to adjust the supporting force exerted by the spring (151) on the annular lower water tank (3).

2. An efficient molten salt thermal energy storage system according to claim 1, characterized in that: An upper slewing bearing (18) is installed on the lower end face of the annular upper water tank (1), and a lower slewing bearing (17) is installed on the upper end face of the annular lower water tank (3). Upper connecting gears (43) and lower connecting gears (44) are respectively fixedly connected to the upper and lower ends of the heating pipe (4). The upper connecting gear (43) meshes with the rotating ring of the upper slewing bearing (18), and the lower connecting gear (44) meshes with the rotating ring of the lower slewing bearing (17). A driving motor (20) for driving the rotating ring of the upper slewing bearing (18) to rotate is installed on the annular upper water tank (1).

3. An efficient molten salt heat storage system according to claim 1, wherein: It also includes an outer thermal insulation cover (21) wrapping the molten salt tank (2). The heating pipe (4) is located inside the outer thermal insulation cover (21), and a thermal insulation filling layer (22) is provided inside the outer thermal insulation cover (21).

4. An efficient molten salt heat storage system according to claim 1, characterized in that: The water inlet pipe (8) passes through the condensation tank (11). One end of the condensation tank (11) is communicated with the annular upper water tank (1) through a steam discharge pipe (10). The other end of the condensation tank (11) is provided with an upward exhaust port (12) and a downward drain port (13).

5. An efficient molten salt heat storage system according to claim 1, characterized in that: It further includes a pressing mechanism (5) for pressing the middle parts of all the heating pipes (4) in the receiving grooves. When the heating pipes (4) rotate, the pressing mechanism (5) releases.

6. An efficient molten salt heat storage system according to claim 5, characterized in that: The pressing mechanism (5) includes a fixed ring (51) fixedly connected to the outer side of the molten salt tank (2), a floating ring (52) sleeved on the outer ring of the fixed ring (51), and a cylinder (55) for driving the floating ring (52) to move up and down. A pressing plate (53) is arranged between the heating pipe (4) and the fixed ring (51). A push rod (54) passing through the outer ring of the fixed ring (51) is fixedly connected to the pressing plate (53). The inner ring of the floating ring (52) is provided with a pressing inclined surface.

7. An efficient molten salt heat storage system according to claim 1, characterized in that: A circulation pipe (16) is communicated between the molten salt inlet pipe (6) and the molten salt outlet pipe (7). A circulation pump is installed on the circulation pipe (16).

8. A method for using the high-efficiency molten salt heat storage system according to claim 1, characterized in that, It includes the following steps: a. High-temperature liquid molten salt enters the molten salt tank (2) through the molten salt inlet pipe (6) to achieve heat storage; b. Water enters the annular upper water tank (1) through the water inlet pipe (8), flows through a plurality of heating pipes (4) to the annular lower water tank (3), and finally flows out through the water outlet pipe (9); c. The heating pipes (4) are attached to the receiving grooves on the outer side of the molten salt tank (2) to keep the molten salt tank (2) warm. At the same time, the heat dissipated by the molten salt tank (2) is transferred to the water in the heating pipes (4) through the heat conduction layer (42) to achieve heating of the water. The contact area between the heat conduction layer (42) and the receiving groove is adjusted by rotating the heating pipes (4) to adjust the water temperature in the heating pipes (4); d. When the contact area between the heat conduction layer (42) and the receiving groove is in the maximum state and the water temperature does not meet the requirements, heating is carried out by the auxiliary electric heating wire in the annular lower water tank (3).

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