A heat storage tank with a heat-insulating and impermeable membrane

Abstract

The application discloses a heat storage tank with a heat insulation anti-seepage film, which comprises a heat storage tank body, a solution groove is arranged on the inner circumferential ring of the middle part of the heat storage tank body, a flexible heat insulation anti-seepage film is arranged on the outer edge of the solution groove, the flexible heat insulation anti-seepage film is used for storing hot working medium in the space of the upper part of the heat storage tank body, the flexible heat insulation anti-seepage film is used for storing cold working medium in the space of the lower part of the heat storage tank body, and the cold and hot fluids between the flexible heat insulation anti-seepage film and the solution groove are a temperature gradient layer.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, and specifically to a thermal storage tank with a heat insulation and anti-seepage membrane. Background Technology

[0002] my country's power generation capacity is still dominated by thermal power, and thermal power plants have heating needs during power generation. Especially in the "Three Norths" region (Northeast, North, and Northwest China), the proportion of combined heat and power (CHP) units is very high, leading to a severe shortage of peak-shaving power sources and significant difficulties in peak shaving. To address this issue, energy storage technology has been widely researched and applied. Energy storage technology can effectively solve the phenomenon of "wind and solar curtailment," achieving "peak shaving and valley filling," thereby improving energy utilization efficiency. Energy storage tanks utilizing sensible thermal energy storage can achieve "thermal-electric decoupling," increasing the safe operating range of unit load and flexibly shaving peak loads. Sensible thermal energy storage tanks are devices that store and release thermal energy using thermal storage materials. This energy storage technology can achieve multiple functions such as peak shaving for CHP units, absorbing wind and solar energy, and recovering industrial waste heat. The advantages of sensible thermal energy storage technology lie in its small tank size, high energy density, high thermal efficiency, and long service life. Therefore, with the continuous development and application of energy storage technology, the application of sensible thermal energy storage technology will become increasingly widespread, providing more reliable support for the sustainable development of my country's energy sector.

[0003] Based on the number of tanks, thermal storage systems can be categorized into single-tank and dual-tank systems. Dual-tank systems typically consist of two tanks, one for storing heat and the other for storing cold, which are then transferred to the desired locations via heat exchangers. This type of system offers advantages such as good stability and safe operation, but suffers from high investment costs and resource waste. In contrast, single-tank systems use only one tank, separating the hot and cold fluids through a thermocline. This results in lower costs compared to dual-tank systems, and offers advantages such as greater flexibility and easier maintenance. Furthermore, single-tank systems can switch between various operating states, such as heat storage, heat release, and cooling, by controlling the fluid flow and temperature. Therefore, single-tank thermal storage systems are a cost-effective, flexible, and easy-to-maintain energy storage technology. In the future energy transition, they will play an increasingly important role, providing more reliable support for my country's sustainable energy development.

[0004] A commonly used single-tank thermal storage tank is the thermocline thermal storage tank. This technology utilizes a stable thermocline to achieve natural stratification of hot and cold fluids within the tank, thus achieving heat storage. A thermocline refers to a temperature gradient that naturally forms under the influence of gravity due to the density difference between hot and cold fluids. The thermocline thermal storage tank, through a rational design of the tank structure and fluid heat transfer method, enables the hot and cold fluids to form a stable thermocline within the tank, thereby achieving the functions of heat storage and release. However, the thickness of the thermocline and the mass exchange between the hot and cold fluids can lead to a decrease in heat storage efficiency. Furthermore, only the same substance can be used for both hot and cold fluids; otherwise, they are prone to mixing. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention aims to provide a thermal storage tank with a heat insulation and anti-seepage membrane. The present invention significantly thins the thermocline layer inside the thermal storage tank, greatly reducing heat exchange between hot and cold fluids and improving the heat storage capacity and efficiency of the thermal storage tank.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A thermal storage tank with a heat insulation and seepage prevention membrane includes a thermal storage tank body 1. A solution tank 10 is arranged around the inner periphery of the middle part of the thermal storage tank body 1. A flexible heat insulation and seepage prevention membrane 9 is installed on the outer edge of the solution tank 10. The flexible heat insulation and seepage prevention membrane 9 and the upper space of the thermal storage tank body store a hot working medium 11. The flexible heat insulation and seepage prevention membrane 9 and the lower space of the thermal storage tank body store a cold working medium 13. The space between the hot and cold fluids separated by the flexible heat insulation and seepage prevention membrane 9 and the solution tank 10 is a temperature inclined layer 12.

[0008] The bottom of the heat storage tank 1 is arc-shaped, meaning that the two sides of the bottom are upturned, which facilitates the discharge of the refrigerant.

[0009] The flexible heat-insulating and seepage-proof membrane 9 has a structure consisting of SiO2 aerogel 14, glass fiber 15, and SiO2 aerogel 16 from top to bottom.

[0010] The upper space of the heat storage tank 1 is equipped with an upper water distributor 4, and the lower space is equipped with a lower water distributor 5. The upper side of the upper water distributor 4 is connected to a hot fluid inlet pipe, and a hot fluid inlet valve 3 is installed on the hot fluid inlet pipe. An overflow pipe is installed on the upper part of the upper water distributor 4, and an overflow valve 2 is installed on the overflow pipe. A hot fluid discharge pipe is connected to the solution tank 10 in the upper space of the heat storage tank 1 to drain the heat working fluid in the tank. A hot fluid discharge valve 8 is installed on the hot fluid discharge pipe. The lower side of the lower water distributor 5 is connected to a cold fluid inlet pipe, and a cold fluid inlet valve 7 is installed on the cold fluid inlet pipe. A cold fluid discharge pipe is installed at the lower part of the lower water distributor 5, and a cold fluid discharge valve 6 is installed on the overflow pipe.

[0011] During operation of the thermal storage tank, it is necessary to ensure that the pressure on both sides of the flexible thermal insulation and seepage prevention membrane 9 is consistent to avoid damage to the flexible thermal insulation and seepage prevention membrane 9.

[0012] Compared with existing technologies, it has the following advantages:

[0013] 1) Compared with common dual-tank thermal storage tanks, the investment cost of this invention is low.

[0014] Firstly, dual-tank thermal storage requires two separate thermal storage tanks, while this invention only requires one separate thermal storage tank. In comparison, the tank cost and installation area are greatly increased. Secondly, in the actual operation of the power plant, the working fluid volume in the dual-tank thermal storage tank can only reach a maximum of half of the designed volume, resulting in a great waste of resources.

[0015] 2) Compared with conventional thermocline thermal storage tanks, the present invention improves the thermal storage efficiency of the thermal storage tank.

[0016] The invention incorporates a flexible heat-insulating and seepage-proof membrane, which greatly reduces heat exchange between the hot and cold working fluids, thereby effectively avoiding heat storage loss caused by the drop in the temperature of the hot fluid and significantly improving the heat storage efficiency of the heat storage tank.

[0017] 3) Compared with conventional inclined thermoelectric storage tanks, it has a wider range of applications.

[0018] The thermocline layer of a conventional thermocline storage tank is relatively thick, so the amount of hot and cold working fluid must reach a certain value; otherwise, the hot and cold working fluid cannot be separated into layers. The flexible heat-insulating and seepage-proof membrane added in this invention can reduce the thickness of the thermocline layer, keeping it very thin. Therefore, even if the amount of hot and cold working fluid stored is small, the temperature difference will not be lost.

[0019] The flexible heat-insulating and seepage-proof membrane used in this invention can not only isolate the heat exchange between hot and cold working fluids, but also achieve the effect of isolating hot and cold working fluids, so that the hot and cold working fluids do not mix. Therefore, the heat storage tank in this invention can be used when the hot and cold working fluids need to be different substances, thus expanding the application range of heat storage tanks.

[0020] 4) Compared with conventional inclined thermocline thermal storage tanks, the present invention reduces tank material consumption and lowers material costs.

[0021] The flexible thermal insulation and seepage prevention membrane of the present invention significantly reduces the thickness of the thermocline layer between the hot and cold working fluids. The thinner the thermocline layer, the smaller the required height of the heat storage tank in the present invention can be compared with that of a conventional thermocline layer heat storage tank when storing the same amount of hot and cold working fluids, thereby effectively reducing material consumption and thus reducing costs.

[0022] 5) Compared with conventional thermocline storage tanks, the present invention can better exhaust hot and cold working fluids.

[0023] This invention adds a solution tank in the middle of the heat storage tank and designs a certain curvature at the bottom of the tank so that when the heat storage tank needs to drain the working fluid inside the tank, the existence of the solution tank in the middle can allow the last remaining small amount of hot working fluid to collect in the tank and be smoothly discharged by the hot fluid discharge pipe. The curvature at the bottom of the heat storage tank can allow the last remaining cold working fluid that is difficult to drain to collect at the center of the bottom of the heat storage tank and finally be discharged by the drain pipe. Attached Figure Description

[0024] Figure 1 This is a structural diagram of the thermal storage tank with heat insulation and seepage prevention membrane of the present invention.

[0025] Figure 2 This is a structural diagram of a heat-insulating and seepage-proof membrane. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0027] Compared to dual-tank systems, geothermal storage tanks offer significant cost savings, simplify system configuration, and reduce equipment investment and operating costs. This technology can alleviate wind and solar power curtailment in northern regions, ensuring residential heating and maintaining social stability. In geothermal storage tanks, the stable formation of the geothermal slope is a prerequisite for normal operation, and the slope thickness is a key technical indicator. A thinner slope allows for a larger usable volume of the storage tank, higher thermal efficiency, and a smaller tank wall height, effectively reducing material consumption and costs. Therefore, the stability and thickness of the geothermal slope must be considered when designing geothermal storage tanks to achieve optimal thermal storage performance and economic benefits.

[0028] This invention adds a flexible, heat-insulating, and leak-proof membrane to a conventional single-tank inclined-temperature layer thermal storage tank, significantly reducing the thickness of the inclined-temperature layer and greatly improving the thermal storage efficiency of the tank. For example... Figure 1 As shown, this thermal storage tank is divided into two modes: thermal storage and thermal release.

[0029] During heat storage, the cold fluid discharge valve 6 is opened, and the cold working fluid originally stored in the heat storage tank 1 flows out from the cold fluid discharge pipe at the bottom of the tank. After being heated outside the tank, it becomes a hot working fluid. The hot fluid inlet valve 3 is then opened, and the hot working fluid flows through the hot fluid inlet pipe and into the heat storage tank 1 through the upper water distributor 4. At this time, as the cold working fluid completes its heat storage and becomes a hot working fluid, the heat insulation and geomembrane 9 slowly sags downward. During heat release, the hot fluid inlet valve 3 is opened, and the hot working fluid is discharged from the hot fluid discharge pipe to supply heat. After the hot working fluid releases heat, its temperature drops and it becomes a cold working fluid. Then, the cold fluid discharge valve 6 is opened, and the cold working fluid flows through the cold fluid inlet pipe and into the heat storage tank 1 through the lower water distributor 5. At this time, the heat insulation and geomembrane 9 slowly bulges upward. The heat insulation effect of the geomembrane greatly reduces the thickness of the thermocline layer and improves the heat storage efficiency of the heat storage tank.

[0030] When the heat storage tank 1 needs to be emptied of its working fluid, the presence of the central solution tank 10 allows the last remaining small amount of hot working fluid to collect in the tank, which is then smoothly discharged through the hot fluid discharge pipe. In addition, the curvature at the bottom of the heat storage tank 1 allows the last remaining cold working fluid to collect at the center of the bottom of the heat storage tank and eventually be discharged through the drain pipe.

[0031] In thermal storage tanks, the heat storage medium is generally water, but other working fluids can also be used depending on different needs, such as aqueous solutions of lithium bromide, lithium chloride, sodium hydroxide, and calcium chloride. The application of this invention can alleviate wind and solar power curtailment in northern regions, ensure residential heating, maintain social stability, and provide more reliable support for the development of clean energy in my country.

[0032] like Figure 2 As shown, the flexible heat-insulating and seepage-proof membrane 9 has a structure consisting of SiO2 aerogel 14, glass fiber 15, and SiO2 aerogel 16 from top to bottom. It is a flexible material that can play the role of heat insulation and seepage prevention.

[0033] This invention adds a flexible, heat-insulating, and leak-proof membrane to the interior of a traditional thermocentric geothermal storage tank, and incorporates a slight curvature at the bottom of the tank to facilitate the drainage of cold fluid when needed. Compared to existing thermocentric geothermal storage tanks, this invention significantly thins the thermocentric layer, greatly reducing heat exchange between hot and cold fluids and improving the storage capacity and efficiency. Existing thermocentric geothermal storage tanks have a relatively thick thermocentric layer, which limits the amount of hot and cold fluids; insufficient working fluid can prevent clear stratification. The thinner thermocentric layer in this invention greatly increases the range of working fluid quantities. Furthermore, the heat-insulating and leak-proof membrane also prevents mass exchange between the hot and cold fluids, allowing the use of different working fluids without mixing. While this invention adds a heat-insulating and leak-proof membrane, increasing the overall cost compared to existing thermocentric geothermal storage tanks, it offers a wider range of applications and superior overall energy storage performance.

Claims

1. A thermal storage tank with a heat insulation and seepage-proof membrane, comprising a thermal storage tank body (1), characterized in that: A solution tank (10) is provided in the inner circumference of the middle part of the heat storage tank (1). The solution tank (10) has an opening facing upward. A flexible heat insulation and seepage prevention membrane (9) is installed on the upper edge of the inner side of the solution tank (10). The flexible heat insulation and seepage prevention membrane (9) and the upper space of the heat storage tank store the heat working medium (11). The flexible heat insulation and seepage prevention membrane (9) and the lower space of the heat storage tank store the cold working medium (13). The space between the flexible heat insulation and seepage prevention membrane (9) and the solution tank (10) is a temperature slope layer (12). The solution tank (10) in the upper space of the heat storage tank (1) is connected to a hot fluid discharge pipe to drain the heat working medium in the tank.

2. A thermal storage tank with a heat-insulating and leak-proof membrane according to claim 1, characterized in that: The bottom of the heat storage tank (1) is arc-shaped, that is, the two sides of the bottom are upturned, which makes it easy to drain the cold working fluid.

3. A thermal storage tank with a heat-insulating and leak-proof membrane according to claim 1, characterized in that: The flexible heat-insulating and seepage-proof membrane (9) has a structure consisting of a first SiO2 aerogel (14), a glass fiber (15), and a second SiO2 aerogel (16) from top to bottom.

4. A thermal storage tank with a heat-insulating and leak-proof membrane according to claim 1, characterized in that: The upper space of the heat storage tank (1) is provided with an upper water distributor (4), and the lower space is provided with a lower water distributor (5). The upper side of the upper water distributor (4) is connected to the hot fluid inlet pipe, and the hot fluid inlet pipe is provided with a hot fluid inlet valve (3). The upper part of the upper water distributor (4) is provided with an overflow pipe, and the overflow pipe is provided with an overflow valve (2). The hot fluid outlet pipe is provided with a hot fluid outlet valve (8). The lower side of the lower water distributor (5) is connected to the cold fluid inlet pipe, and the cold fluid inlet pipe is provided with a cold fluid inlet valve (7). The lower part of the lower water distributor (5) is provided with a cold fluid outlet pipe, and the outlet pipe is provided with a cold fluid outlet valve (6).

5. A thermal storage tank with a heat-insulating and leak-proof membrane according to claim 1, characterized in that: When the thermal storage tank is in operation, it is necessary to ensure that the pressure on both sides of the flexible thermal insulation and seepage prevention membrane (9) is consistent in order to avoid damage to the flexible thermal insulation and seepage prevention membrane (9).

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