Energy storage device

Abstract

An energy storage device comprises an energy storage tank containing an energy storage carrier and a coil pipe installed in the energy storage tank and used for allowing an energy transfer medium to go in and out, the coil pipe comprises a first straight pipe, a second straight pipe and a plurality of S-shaped pipes, and the first straight pipe and the second straight pipe are arranged in parallel in the vertical direction of the height of the energy storage tank; the multiple S-shaped pipes are vertically arranged to be parallel to the first straight pipe and periodically extend to the second straight pipe, every two adjacent S-shaped pipes in the multiple S-shaped pipes are staggered in the extending direction, and every two nearest S-shaped pipes which are separated are not staggered in the extending direction. The energy storage carriers with different heights in the energy storage tank can store energy uniformly during energy storage, and the temperatures of the energy transfer media in the S-shaped pipes are close during energy release, so that the temperature of the energy transfer media flowing out of the energy storage device through the second straight pipes is stable, the heat exchange stability is maintained, and the heat exchange efficiency is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage, in particular to an energy storage device. BACKGROUND

[0002] In the conventional energy storage device, the S-shaped pipes in the energy storage tank are arranged in one or more layers in the horizontal direction, and each layer of S-shaped pipes exchanges heat at different heights of the energy storage tank. Because the density of liquid increases with lower temperature, the liquid with high density will sink to the bottom of the energy storage tank under the action of gravity, so the temperature of the energy storage carrier at the bottom of the energy storage tank is lower than that of the energy storage carrier at the top during the energy storage process. The uneven temperature of the energy storage carrier in the energy storage tank causes the energy transfer medium in each S-shaped pipe to absorb different amounts of energy from the energy storage carrier at different heights during the heat exchange and energy release process, and the temperature of the energy transfer medium flowing out of the outlet end of each layer of S-shaped pipes is different, so the temperature of the energy transfer medium flowing out of the energy storage device fluctuates, resulting in unstable heat exchange.

[0003] In addition, the ethylene glycol aqueous solution in the S-shaped pipe of the existing energy storage device cools the water in the energy storage tank to make ice, and after the ice storage is completed, the water in the energy storage tank has been converted from liquid to solid ice, which has very high mechanical strength and the volume will also increase by 3% to 8%. Solid ice usually needs to consume energy to be crushed, and then the cold energy is transferred to the air conditioning system by the ethylene glycol aqueous solution in the S-shaped pipe through the water pump and the plate heat exchanger for use by the user, and at the same time, the small crushed ice has poor flowability and is not easy to be converted and utilized. CONTENT OF THE UTILITY MODEL

[0004] In order to solve the technical problems of unstable heat exchange and low heat exchange efficiency of the existing energy storage device, the present application provides an energy storage device, which comprises an energy storage tank containing an energy storage carrier and a coil pipe installed inside the energy storage tank for the inlet and outlet of an energy transfer medium, the coil pipe comprising a first straight pipe, a second straight pipe and a plurality of S-shaped pipes, the first straight pipe and the second straight pipe being arranged in parallel in the vertical direction of the height of the energy storage tank, the plurality of S-shaped pipes being arranged vertically in parallel and periodically from the first straight pipe to the second straight pipe, and the two adjacent S-shaped pipes in the plurality of S-shaped pipes being staggered in the extension direction, and the two nearest S-shaped pipes being not staggered in the extension direction.

[0005] According to the technical scheme, the plurality of S-shaped pipes are vertically arranged in the energy storage tank to extend from the first straight pipe to the second straight pipe in parallel and periodically, the energy transfer medium in each S-shaped pipe exchanges energy with the energy storage carriers at different heights in the energy storage tank, on one hand, the energy storage carriers at different heights in the energy storage tank are uniformly stored, and on the other hand, the temperature of the energy transfer medium in each S-shaped pipe is similar when energy is released, the temperature of the energy transfer medium flowing out of the energy storage device through the straight pipe is stable, and the two adjacent S-shaped pipes in the plurality of S-shaped pipes are staggered in the extension direction, and the two closest S-shaped pipes are not staggered in the extension direction, so that the heat exchange between the energy transfer medium in the S-shaped pipe and the energy storage carriers in the energy storage tank is more uniform, and therefore, the energy storage device with the above structure can maintain stable heat exchange during heat exchange and ensure heat exchange efficiency.

[0006] In some embodiments, the distance between the two adjacent S-shaped pipes in the plurality of S-shaped pipes is 20-30 cm, optionally 20 cm, 22 cm, 25 cm, 28 cm, 30 cm, and preferably 20 cm. The distance between the two adjacent S-shaped pipes is 20-30 cm, which can control the number of S-shaped pipes and thus the cost while ensuring heat exchange efficiency.

[0007] In some embodiments, the distance between the bottom of each S-shaped pipe in the plurality of S-shaped pipes and the bottom of the inner cavity of the energy storage tank is 1 / 8-1 / 4 of the height of the inner cavity of the energy storage tank, and the distance between the top of each S-shaped pipe and the top of the inner cavity of the energy storage tank is 1 / 8-1 / 4 of the height of the inner cavity of the energy storage tank, and preferably 1 / 8. If the distance between the top is too large, the heat exchange efficiency of the top energy storage carrier in the cavity of the energy storage tank is low, and if the distance is too small, the energy storage carrier in the energy storage tank is easy to expand and damage the energy storage device.

[0008] In some embodiments, the distance between the two adjacent S-shaped pipes in the plurality of S-shaped pipes is 20-30 cm, optionally 20 cm, 22 cm, 25 cm, 28 cm, 30 cm, and preferably 20 cm. The distance between the two adjacent S-shaped pipes is 20-30 cm, which can control the number of S-shaped pipes and thus the cost while ensuring heat exchange efficiency.

[0009] In some embodiments, the energy storage tank further comprises a plurality of support plates vertically fixed in the energy storage tank, and the plurality of S-shaped pipes are fixed in the energy storage tank through the support plates.

[0010] In some embodiments, the tank wall of the energy storage tank comprises an inner container, an intermediate thermal insulation layer and a surface protection layer. The energy transfer in the energy storage tank can be prevented from being lost to the outside to the maximum extent. The inner container of the tank wall of the energy storage tank can be a 304 stainless steel inner container with a thickness of 3-5 mm, the intermediate thermal insulation layer can be a polyurethane thermal insulation layer with a thickness of 5-10 mm, and the surface protection layer can be a 304 stainless steel with a thickness of 0.5 mm. The tank wall of the energy storage tank is also provided with a viewing mirror for observing the state of the liquid in the cavity of the energy storage tank. The higher the height of the energy storage tank, the greater the thickness of the inner container of the tank wall.

[0011] In some embodiments, the energy storage carrier and the energy transfer medium are aqueous ethylene glycol solutions with different freezing points, and the freezing point of the energy transfer medium is lower than that of the energy storage carrier. The freezing point of aqueous ethylene glycol solution is lower than that of water, and the higher the concentration of aqueous ethylene glycol solution, the lower the freezing point. Using aqueous ethylene glycol solution with a low freezing point as an energy storage carrier can store more energy during the energy storage process.

[0012] In some embodiments, the freezing point of the energy transfer medium is more than 15°C lower than that of the energy storage carrier, which can ensure that the energy transfer medium does not freeze or become viscous when the minimum cooling temperature is met during the cold storage process, and does not produce flocculation due to low temperature, resulting in poor flowability and selective failure of the water pump due to excessive operating current. During the cold storage process, the aqueous ethylene glycol solution in the energy storage tank can be kept in a semi-flowing ice slurry or micro-ice state, and more cold energy can be stored by phase change from solid to liquid.

[0013] In some embodiments, the inner and / or outer surfaces of the walls of the plurality of S-shaped pipes are superconducting coatings or heat transfer layers formed of heat transfer materials. The superconducting coatings or heat transfer layers contain graphene or other high thermal conductivity materials. The superconducting coatings can increase the heat transfer efficiency between the media inside and outside the S-shaped pipes. The S-shaped pipes are made of materials with good thermal conductivity, such as stainless steel or aluminum, aluminum alloy, etc.

[0014] The energy storage device of the present application can be used for cold storage or heat storage. In some embodiments, the energy storage device is a cold storage device. In other embodiments, the energy storage device is a heat storage device. BRIEF DESCRIPTION OF DRAWINGS

[0015] The present application will be further described below with reference to the accompanying drawings and examples. In the drawings:

[0016] Figure 1 is a side view of the energy storage device;

[0017] Figure 2 is a top view of the energy storage device;

[0018] Figure 3 is a structural schematic diagram of the energy storage air conditioning system.

[0019] REFERENCE SIGNS

[0020] 10 energy storage device; 101 energy storage tank; 1011 stainless steel surface protection layer; 1012 polyurethane insulation layer; 1013 stainless steel inner container; 1014 observation mirror; 102 coil pipe; 1021 S-shaped pipe; 1022 first straight pipe; 1023 second straight pipe; 103 support plate; 20 refrigeration unit; 30 cooling tower; 40 cold storage heat exchanger; 50 air-cooled heat pump unit; 60 heat storage heat exchanger; 70 refrigeration / cold exchange conversion three-way valve; 80 cold storage / heat storage conversion water valve; 90 winter / summer conversion electric valve; 100 heat storage / heat dissipation conversion electric valve. DETAILED DESCRIPTION

[0021] The technical solutions of the present application will be described in detail below in combination with the drawings and examples, but the present application is not limited in the scope of the examples.

[0022] Example 1

[0023] As shown in Figure 1 and Figure 2 , the energy storage device 10 includes an energy storage tank 101 containing an energy storage carrier and a coil pipe 102 installed in the energy storage tank 101 for the inlet and outlet of the energy transfer medium.

[0024] The tank wall of the energy storage tank 101 includes a 3mm 304 stainless steel inner container 1013, a 5mm polyurethane insulation layer 1012, and a 0.5mm 304 stainless steel surface protection layer 1011. An observation mirror 1014 is also installed on the energy storage tank 101 for observing the state of the liquid in the energy storage tank. The height of the energy storage tank 101 is 80cm.

[0025] The coil pipe 102 includes a first straight pipe 1022, a second straight pipe 1023, and a plurality of S-shaped pipes 1021. The first straight pipe 1022 and the second straight pipe 1023 are arranged in parallel in the vertical direction of the height of the energy storage tank 101. The inlet pipe of the coil pipe 102 (the first straight pipe 1022) and the outlet pipe of the coil pipe 102 (the second straight pipe 1023) are respectively located on opposite sides of the bottom of the energy storage tank 101. The plurality of S-shaped pipes 1021 are respectively arranged vertically to extend from the first straight pipe 1022 in parallel and periodically to the second straight pipe 1023, and adjacent two S-shaped pipes 1021 are staggered in the extension direction, and the two nearest S-shaped pipes 1021 are not staggered in the extension direction. The distance between the two adjacent S-shaped pipes 1021 staggered in the extension direction is the straight line distance between the adjacent peaks and valleys of the same S-shaped pipe 1021 in the extension direction.

[0026] The distance between two adjacent S-shaped pipes 1021 is 20 cm. The bottom of each S-shaped pipe 1021 is adjacent to the bottom of the inner cavity of the energy storage tank 101, and the distance from the top of the S-shaped pipe 1021 to the top of the cavity of the energy storage tank 101 is 1 / 8 of the height of the energy storage tank 101, that is, the distance from the top of the S-shaped pipe 1021 to the top of the cavity of the energy storage tank 101 is 10 cm. The S-shaped pipe 1021 is fixed in the energy storage tank 101 by a plurality of support plates 103 fixed vertically in the energy storage tank 101. The inner and outer surfaces of the pipe wall of the plurality of S-shaped pipes 1021 are coated with a superconducting coating containing graphene.

[0027] The freezing point of the ethylene glycol aqueous solution selected as the energy storage carrier in the energy storage tank 101 is 20℃, and the freezing point of the ethylene glycol aqueous solution selected as the energy transfer medium in the S-shaped pipe 1021 is -38℃.

[0028] During the energy storage process, the energy transfer medium at -20 to -28℃ enters the first straight pipe 1022, then enters each S-shaped pipe 1021 to transfer cold energy to the energy storage carrier with a high freezing point in the energy storage tank 101, and then flows out of the energy storage device 10 through the outlet of the second straight pipe 1023. This cycle continuously transfers cold energy to the energy storage carrier in the energy storage tank 101. When the temperature of the energy storage carrier in the energy storage tank 101 reaches 2℃ below the freezing point (at this time, the energy storage carrier in the energy storage tank 101 is in the state of ice slurry) or the low-price period of electricity ends, the energy storage stops. During the energy release process, the high-temperature energy transfer medium in the S-shaped pipe 1021 flows into the first straight pipe 1022 and then enters the S-shaped pipe 1021 to absorb the cold energy of the low-temperature energy storage carrier in the energy storage tank 101. The energy transfer medium after cooling flows out of the energy storage device 10 through the outlet of the second straight pipe 1023, and this cycle continuously transfers cold energy to the air conditioning system for use.

[0029] During the energy storage process, the energy transfer medium at -20 to -28℃ enters the first straight pipe 1022, then enters each S-shaped pipe 1021 to transfer cold energy to the energy storage carrier with a high freezing point in the energy storage tank 101, and then flows out of the energy storage device 10 through the outlet of the second straight pipe 1023. This cycle continuously transfers cold energy to the energy storage carrier in the energy storage tank 101. When the temperature of the energy storage carrier in the energy storage tank 101 reaches 2℃ below the freezing point (at this time, the energy storage carrier in the energy storage tank 101 is in the state of ice slurry) or the low-price period of electricity ends, the energy storage stops. During the energy release process, the high-temperature energy transfer medium in the S-shaped pipe 1021 flows into the first straight pipe 1022 and then enters the S-shaped pipe 1021 to absorb the cold energy of the low-temperature energy storage carrier in the energy storage tank 101. The energy transfer medium after cooling flows out of the energy storage device 10 through the outlet of the second straight pipe 1023, and this cycle continuously transfers cold energy to the air conditioning system for use.

[0030] Example 2

[0031] As Figure 3As shown, in the cold storage phase, the compressor of the refrigeration unit 20 is started. The heat generated by the refrigeration unit 20 is carried by tap water as the carrier through the cooling water pump to the cooling tower 30 (since the low tariff period is mostly at night, the unit is operated at night, and the cooling tower has better heat dissipation effect than in the daytime), and the heat generated by the refrigeration unit 20 is dissipated into the air by the cooling fan, and the cooled cooling water is pumped back to the refrigeration unit 20 through the pipeline to form a closed loop. The energy transfer medium 45%-59% of ethylene glycol solution (freezing temperature about -38℃) carries the cold generated by the operation of the refrigeration unit 20 to the first straight pipe 1022 of the energy storage device 10 through the water pump and the pipeline, and then to each S-shaped pipe 1021 to transfer the cold to the energy storage carrier 30% of ethylene glycol solution (freezing temperature -20℃) in the energy storage tank 101. The energy transfer medium after transferring the cold flows out of the energy storage device 10 through the second straight pipe 1023 outlet and returns to the refrigeration unit 20 to take away the cold. This is repeated to cool the energy storage carrier in the energy storage tank 101 to -22℃ to form ice slurry. When the energy storage carrier in the energy storage tank 101 reaches ice slurry or the low tariff period ends, the refrigeration unit 20 stops refrigeration. The energy transfer medium is controlled by the refrigeration / cold exchange three-way valve 70 to no longer pass through the refrigeration unit 20, and the energy storage stops. In the energy release process, the high-temperature energy transfer medium enters the S-shaped pipe 1021 through the first straight pipe 1022 to absorb the cold of the low-temperature energy storage carrier in the energy storage tank 101, and the cooled energy transfer medium flows out through the second straight pipe 1023 outlet to take away the cold from the energy storage device 10 and transfer it to the air conditioning chilled water circuit through the cold storage heat exchanger 40 to provide a cold source for the air conditioning system.

[0032] In the heat storage phase, the heat storage path is connected by adjusting the winter-summer conversion electric valve 90 and the cold storage / heat storage conversion water valve 80 to control the flow of the energy transfer medium in the heat storage system. The energy transfer medium transfers the heat generated by the air-cooled heat pump unit 50 to the energy transfer medium in the S-shaped pipe 1021 through the heat storage heat exchanger 60, and the energy transfer medium further transfers the heat to the energy storage carrier in the energy storage tank 101. After the energy storage is completed, the heat storage / heat dissipation conversion electric valve 100 is switched to connect the heat dissipation path, and the energy transfer medium no longer transfers heat to the energy storage device 10 through the heat storage heat exchanger 60. The low-temperature energy transfer medium enters the S-shaped pipe 1021 through the first straight pipe 1022 to absorb the heat of the high-temperature energy storage carrier in the energy storage tank 101, and then flows out through the second straight pipe 1023 outlet to take away the heat from the energy storage device 10 and transfer it to the air conditioning hot water circuit through the heat storage heat exchanger 60 to provide a heat source for the air conditioning system.

[0033] In summary, the application sets multiple S-shaped pipes in the energy storage tank of the energy storage device, the adjacent two S-shaped pipes are staggered in the extension direction, and the two nearest S-shaped pipes are not staggered in the extension direction, so that the energy storage of the energy storage carrier at different heights in the energy storage tank is uniform during energy storage, the temperature of the energy transfer medium in each S-shaped pipe is similar during energy release, the temperature of the energy transfer medium flowing out of the energy storage device through the second straight pipe is stable, so as to maintain stable heat exchange and ensure heat exchange efficiency.

[0034] The above description is only an embodiment of the application, which is only used to help understand the application and does not limit the protection scope of the application. It should be pointed out that some improvements made by those skilled in the art without departing from the principles of the application should also be regarded as the protection scope of the application.

Claims

1. An energy storage device, the energy storage device comprising an energy storage tank for accommodating an energy storage carrier and a coil installed inside the energy storage tank for the entry and exit of an energy transfer medium, characterized in that, The coil includes a first straight tube, a second straight tube, and multiple S-shaped tubes. The first straight tube and the second straight tube are arranged parallel to each other in the vertical direction of the energy storage tank. The multiple S-shaped tubes are arranged vertically and extend periodically from the first straight tube to the second straight tube. Among the multiple S-shaped tubes, two adjacent S-shaped tubes are staggered in the extension direction, and the two closest S-shaped tubes are not staggered in the extension direction.

2. The energy storage device according to claim 1, characterized in that, The spacing between two adjacent S-shaped tubes in the plurality of S-shaped tubes is 20-30cm.

3. The energy storage device according to claim 1, characterized in that, In the plurality of S-shaped tubes, the bottom of each S-shaped tube is adjacent to the bottom of the inner cavity of the energy storage tank at the height of the energy storage tank, and the distance between the top of the tube and the top of the inner cavity of the energy storage tank is 1 / 8 to 1 / 4 of the height of the inner cavity of the energy storage tank.

4. The energy storage device according to claim 3, characterized in that, The distance between the top of each S-shaped tube at the height of the energy storage tank and the top of the inner cavity of the energy storage tank is 1 / 8 of the height of the inner cavity of the energy storage tank.

5. The energy storage device according to claim 1, characterized in that, The distance between two adjacent S-shaped tubes in the extension direction is the straight-line distance between adjacent crests and troughs of the same S-shaped tube in the extension direction.

6. The energy storage device according to claim 1, characterized in that, It also includes multiple support plates that are vertically fixed in the energy storage tank, and the multiple S-shaped tubes are respectively fixed in the energy storage tank by the support plates.

7. The energy storage device according to claim 1, characterized in that, The energy storage tank wall includes an inner liner, an intermediate insulation layer, and a surface protective layer.

8. The energy storage device according to claim 1, characterized in that, The energy storage carrier and the energy transfer medium are ethylene glycol aqueous solutions with different freezing points, and the freezing point of the energy transfer medium is lower than that of the energy storage carrier.

9. The energy storage device according to claim 8, characterized in that, The freezing point of the energy transfer medium is more than 15°C lower than that of the energy storage carrier.

10. The energy storage device according to any one of claims 1-9, characterized in that, The inner and / or outer surfaces of the multiple S-shaped tubes are coated with a superconducting coating.

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