Reversible conical phase change thermal storage system

Abstract

The embodiment of the application provides a reversible circular cone type phase change heat storage system. The phase change heat storage system comprises an energy storage unit, a fluid transportation channel and a reversing mechanism. The energy storage unit comprises a heat preservation material, a shell and a phase change material, and is used for storing and releasing heat of the system. The fluid transportation channel is located in the inside of the energy storage unit, and comprises a gradually expanding channel, a gradually shrinking channel and a heat exchange pipeline, and is used for providing heat for the energy storage unit. The reversing mechanism is connected with the energy storage unit, and comprises a rotating shaft, a buffer device, a three-dimensional bearing support and a stepping motor, and is used for reversing the energy storage unit in the heat storage and release process, so that the energy storage unit stores and releases heat at a preset rate. Through the above technical scheme, the rate of the heat storage and release process of the phase change heat storage system can be ensured to be consistent, the problem of uneven heat exchange caused by natural convection is solved, and the heat exchange performance of the phase change heat storage system is significantly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat storage, in particular to a reversible conical phase change heat storage system. BACKGROUND

[0002] With the depletion of traditional fossil energy and the worsening of ecological environment, the development and utilization of renewable energy has attracted more attention. In China, industrial energy consumption accounts for more than 70% of total energy consumption, of which more than 50% of industrial energy consumption is converted into industrial waste heat, and the recoverable waste heat resources account for 60% of the total waste heat resources. However, the current utilization rate of industrial waste heat in China is only about 30%. The intermittency, instability and low energy density of energy are the main obstacles to its popularization and application. Phase change heat storage technology can solve these obstacles because it can absorb or release a large amount of heat energy within a small change in temperature. The heat storage device has the function of heat exchange, which transfers heat from high temperature fluid to low temperature fluid, and the main types are shell and tube, plate, packed bed. Among them, the shell and tube heat storage device has mature technology, low cost, strong adaptability, low processing requirement, can load more weight of phase change material, and is suitable for high temperature, high pressure and high flow occasions, so it is most widely used in industrial applications. However, during the heat storage process, due to the influence of natural convection, the liquid phase change material moves upward under the action of buoyancy force, so that the heat exchange rate of the upper part of the heat storage device is faster than that of the lower part, and the heat exchange rate of the heat release process is just the opposite. This phenomenon leads to uneven heat exchange of the whole heat storage system, which seriously affects the performance of the heat storage system. SUMMARY

[0003] The purpose of the embodiment of the present application is to provide a reversible conical phase change heat storage system.

[0004] In order to achieve the above purpose, the first aspect of the present application provides a reversible conical phase change heat storage system, comprising:

[0005] The energy storage unit comprises heat preservation material, shell and phase change material, and is used for storing and releasing heat of the system, wherein the heat preservation material is wrapped outside the shell, and the phase change material is uniformly filled between the shell and the heat exchange pipeline;

[0006] The fluid transportation channel is located in the inside of the energy storage unit, comprising a gradually expanding channel, a gradually contracting channel and a heat exchange pipeline, and is used for providing heat for the energy storage unit, wherein the heat exchange pipeline is uniformly distributed in the inside of the shell, and the gradually expanding channel and the gradually contracting channel are located on both sides of the shell;

[0007] The turnover mechanism is connected with the energy storage unit and comprises a rotating shaft, a buffer device, a three-dimensional bearing support and a stepping motor, and is used for overturning the energy storage unit during heat storage and heat release, so that the energy storage unit stores and releases heat at a preset rate. The three-dimensional bearing support is connected with the rotating shaft, the buffer device is located at the bottom of the energy storage unit, the three-dimensional bearing support and the buffer device provide support for the rotating shaft and the shell, the stepping motor is connected with the rotating shaft, the rotating shaft is connected with the shell, and the stepping motor drives the rotating shaft to rotate to realize the overturning of the energy storage unit during heat storage and / or heat release.

[0008] During heat storage, the gradually expanding channel is at the upper end and the gradually shrinking channel is at the lower end, the high-temperature heat exchange fluid flows into the shell from the gradually expanding channel, heat is transferred to the phase change material in the form of convection and conduction, the phase change material absorbs heat and changes from solid to liquid to store heat.

[0009] During heat release, the gradually shrinking channel is at the upper end and the gradually expanding channel is at the lower end, the low-temperature heat exchange fluid flows into the shell from the gradually expanding channel, heat is transferred to the low-temperature heat exchange fluid in the form of convection and conduction, and the phase change material releases heat and changes from liquid to solid to release heat.

[0010] In the embodiments of the present application, the cross sections of the gradually expanding channel and the gradually shrinking channel are always circular cross sections.

[0011] In the embodiments of the present application, the heat exchange pipeline is a heat exchange pipeline with fins, wherein the structure of the fins is any one of snowflake type, spider web type and tree branch type.

[0012] In the embodiments of the present application, the pipe diameter of the heat exchange pipeline remains unchanged, and the size of the fins gradually decreases from the gradually expanding channel end to the gradually shrinking channel end.

[0013] In the embodiments of the present application, the material of the heat exchange pipeline is copper or aluminum.

[0014] In the embodiments of the present application, the structure of the phase change heat storage system is shell and tube type, and the materials of the three-dimensional bearing support, the rotating shaft, the gradually expanding channel, the gradually shrinking channel, the shell, the top cover and the bottom cover of the phase change heat storage system are any one kind of metal material.

[0015] In the embodiments of the present application, the phase change material is replaced according to the actual heat use temperature, and the replaced type is any one of paraffin, alcohol and salt.

[0016] In the embodiments of the present application, the stepping motor drives the rotating shaft to rotate to realize the overturning of the energy storage unit during heat storage and / or heat release, and the overturning angle is 0-180°.

[0017] In the embodiment of the present application, the ratio of the first bottom surface diameter R and the second bottom surface diameter r of the shell is 1.2-1.4; wherein, during the heat storage process, R is the high-temperature heat exchange fluid inlet section circle diameter, and r is the high-temperature heat exchange fluid outlet section circle diameter; during the heat release process, R is the low-temperature heat exchange fluid inlet section circle diameter, and r is the low-temperature heat exchange fluid outlet section circle diameter.

[0018] In the embodiment of the present application, the phase change heat storage system further comprises a temperature sensor for measuring the inlet temperature of the heat exchange fluid entering the energy storage unit and the outlet temperature of the heat exchange fluid flowing out of the energy storage unit; wherein, during the heat storage, in the case that the temperature difference between the inlet temperature and the outlet temperature is less than a preset temperature threshold, it is determined that the heat storage is completed, the connection valve between the fluid inlet end and the outlet end and the heat exchange pipeline is disconnected, and the overturning mechanical operation is reversed, the rotation shaft is driven to rotate by the stepping motor to overturn the entire energy storage unit by 180°, and the connection valve is reconnected with the fluid inlet end and the outlet end; during the heat release, in the case that the temperature difference between the inlet temperature and the outlet temperature is less than a preset temperature threshold, it is determined that the heat release is completed, the connection valve between the fluid inlet end and the outlet end and the heat exchange pipeline is disconnected, and the overturning mechanical operation is reversed, the rotation shaft is driven to rotate by the stepping motor to overturn the entire energy storage unit by 180°, and the connection valve is reconnected with the fluid inlet end and the outlet end.

[0019] Through the above technical solution, the energy storage unit is used to store and release the heat of the overturnable circular truncated cone type phase change heat storage system; the fluid transportation channel can provide heat for the energy storage unit; the overturning mechanism, connected with the energy storage unit, can overturn the energy storage unit during the heat storage and release process, so that the gradually expanding channel is at the upper end and the gradually shrinking channel is at the lower end during the heat storage; the gradually shrinking channel is at the upper end and the gradually expanding channel is at the lower end during the heat release. The technical solution can ensure the consistency of the heat storage and release rate of the phase change heat storage system, solve the problem of uneven heat exchange caused by natural convection, and significantly improve the heat exchange performance of the phase change heat storage system.

[0020] Other features and advantages of the embodiments of the present application will be described in detail in the following specific implementation part. BRIEF DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings are included to provide a further understanding of the embodiments of the present application, and constitute a part of the specification, and are used together with the following specific implementation to explain the embodiments of the present application, but do not constitute a limitation on the embodiments of the present application. In the drawings:

[0022] Figure 1 The schematic diagram of the overturnable circular truncated cone type phase change heat storage system according to the embodiments of the present application is schematically shown;

[0023] Figure 2 The size schematic diagram of the shell of the overturnable circular truncated cone type phase change heat storage system according to the embodiments of the present application is schematically shown;

[0024] Figure 3 Fig. 1 schematically shows a structural schematic diagram of a finned heat exchange pipe according to an embodiment of the present application;

[0025] Figure 4 Fig. 2 schematically shows a cross-sectional view of a finned heat exchange pipe according to an embodiment of the present application;

[0026] Figure 5 Fig. 3 schematically shows a vertical cross-sectional view of a three-dimensional bearing support according to an embodiment of the present application;

[0027] Figure 6 Fig. 4 schematically shows a schematic diagram of a heat exchange fluid inlet and outlet according to an embodiment of the present application;

[0028] Figure 7 Fig. 5 schematically shows a structural block diagram of a reversible frustum-type phase change heat storage system according to an embodiment of the present application.

[0029] Reference signs

[0030] 1 diverging channel 2 heat exchange pipe

[0031] 3 phase change material 4 rotating shaft

[0032] 5 housing 6 converging channel

[0033] 7 buffer device 8 three-dimensional bearing support

[0034] 9 stepper motor 10 heat preservation material

[0035] 11 high-temperature heat exchange fluid 12 low-temperature heat exchange fluid DETAILED DESCRIPTION

[0036] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. It should be understood that the specific embodiments described herein are only used to illustrate and explain the embodiments of the present application, and are not used to limit the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0037] Figure 1 Fig. 5 schematically shows a structural schematic diagram of a reversible frustum-type phase change heat storage system according to an embodiment of the present application. As shown in the figure, in an embodiment of the present application, a reversible frustum-type phase change heat storage system is provided, comprising: Figure 1

[0038] ​The energy storage unit includes the heat preservation material 10, the shell 5 and the phase change material 3, is used for storing and releasing the heat of the system, wherein the heat preservation material 10 is wrapped on the outside of the shell 5, and the phase change material 3 is uniformly filled between the shell 5 and the heat exchange pipeline 2;

[0039] The fluid transportation channel is located in the inside of the energy storage unit, includes the gradually expanding channel 1, the gradually shrinking channel 6 and the heat exchange pipeline 2, and is used for providing heat for the energy storage unit, wherein the heat exchange pipeline 2 is uniformly distributed in the inside of the shell 5, and the gradually expanding channel 1 and the gradually shrinking channel 6 are located on both sides of the shell 5.

[0040] The turnover mechanism is connected with the energy storage unit, includes the rotating shaft 4, the buffer device 7, the three-dimensional bearing support 8 and the stepping motor 9, is used for turning over the energy storage unit in the heat storage and release process, so that the energy storage unit stores and releases heat at a preset rate, wherein the three-dimensional bearing support 8 is connected with the rotating shaft 4, the buffer device 7 is located at the bottom of the energy storage unit, the three-dimensional bearing support 8 and the buffer device 7 provide support for the rotating shaft 4 and the shell 5, the stepping motor 9 is connected with the rotating shaft 4, the rotating shaft 4 is connected with the shell 5, and the stepping motor 9 drives the rotating shaft 4 to rotate to realize the turnover of the energy storage unit in the heat storage and / or release process.

[0041] The phase change heat storage is a high-tech energy storage technology based on phase change energy storage material. The phase change heat storage can be divided into solid-liquid phase change, liquid-gas phase change and solid-gas phase change. The phase change heat storage system can solve the contradiction between energy supply time and space, and is one of the important ways to improve energy utilization. The turnoverable circular truncated cone type phase change heat storage system can include an energy storage unit, a fluid transportation channel and a turnover mechanism. The energy storage unit can be a circular truncated cone type, and can include a heat preservation material 10, a shell 5 and a phase change material 3. The fluid transportation channel can include a gradually expanding channel 1, a gradually shrinking channel 6 and a heat exchange pipeline 2. The turnover mechanism can include a gradually expanding channel 1, a gradually shrinking channel 6 and a heat exchange pipeline 2. During heat storage, the gradually expanding channel 1 is at the upper end, the gradually shrinking channel 6 is at the lower end, the high-temperature heat exchange fluid flows into the shell 5 from the gradually expanding channel 1, the heat is transferred to the phase change material 3 in the form of convection and conduction, the phase change material 3 absorbs heat and changes from solid to liquid to store heat; during heat release, the gradually shrinking channel 6 is at the upper end, the gradually expanding channel 1 is at the lower end, the low-temperature heat exchange fluid flows into the shell 5 from the gradually expanding channel 1, the heat is transferred to the low-temperature heat exchange fluid in the form of convection and conduction, and the phase change material 3 releases heat and changes from liquid to solid to release heat.

[0042] In one embodiment, the ratio of the first bottom diameter R and the second bottom diameter r of the shell 5 is 1.2-1.4. Wherein, during the heat storage process, R is the circular diameter of the high-temperature heat exchange fluid inlet cross section, and r is the circular diameter of the high-temperature heat exchange fluid outlet cross section; during the heat release process, R is the circular diameter of the low-temperature heat exchange fluid inlet cross section, and r is the circular diameter of the low-temperature heat exchange fluid outlet cross section. Figure 2The size of the shell of the reversible circular truncated cone phase change heat storage system according to the embodiment of the present application is schematically shown. As shown in Figure 2 The shell 5 can include a first bottom diameter R and a second bottom diameter r. The ratio of the first bottom diameter R to the second bottom diameter r can be 1.2-1.4. During heat storage, the high-temperature heat exchange fluid enters the energy storage unit through the inlet with diameter R and flows out of the energy storage unit through the outlet with diameter r. During heat release, the low-temperature heat exchange fluid enters the energy storage unit through the inlet with diameter R and flows out of the energy storage unit through the outlet with diameter r.

[0043] In one embodiment, the cross sections of the diverging channel 1 and the converging channel 6 are always concentric. The diverging channel 1 and the converging channel 6 can be located on the two sides of the shell 5, respectively. When the phase change heat storage system is working, the diverging channel 1 and the converging channel 6 can be connected with the heat exchange pipeline 2 and the shell 5, so that the fluid can enter and exit the phase change heat storage system through the diverging channel 1 and the converging channel 6.

[0044] In one embodiment, the heat exchange pipeline 2 can be a heat exchange pipeline with fins. The structure of the fins can be any one of snowflake type, spider web type, and tree branch type. The heat exchange pipeline 2 is uniformly distributed in the interior of the shell 5, and the heat exchange fluid can exchange heat with the phase change material 3 through the heat exchange pipeline 2. The phase change material refers to a substance that changes form with temperature and can provide latent heat. The process of changing from solid to liquid or from liquid to solid is a phase change process, in which the phase change material absorbs or releases a large amount of latent heat. The phase change material can be divided into refrigeration phase change material, low-temperature phase change material, medium-temperature phase change material, and high-temperature phase change material. The temperature range of the refrigeration phase change material can be below 15℃, the temperature range of the low-temperature phase change material can be 15-90℃, the temperature range of the medium-temperature phase change material can be 90-550℃, and the temperature range of the high-temperature phase change material can be greater than 550℃.

[0045] Figure 3 The structure of the heat exchange pipeline with fins according to the embodiment of the present application is schematically shown. As shown in Figure 3 The diameter of the heat exchange pipeline is maintained unchanged, and the size of the fins gradually decreases from the end of the diverging channel to the end of the converging channel. The size of the fins can be adjusted according to actual needs by the designer. The heat exchange pipeline with fins can effectively increase the heat exchange area and improve the heat transfer efficiency.

[0046] In one embodiment, the phase change material is replaced according to the actual heat utilization temperature, and the replaced type is any one of paraffin, alcohol and salt. Among them, the paraffin phase change material has the advantages of high phase change latent heat, wide phase change temperature range, no supercooling phenomenon and low price, and the chemical properties of the paraffin phase change material are stable, suitable for long-term use. The alcohol phase change material has the advantages of good phase change temperature adaptability, large phase change latent heat, stable physical and chemical properties, and good formability when in solid state. The salt phase change material has a high phase change temperature, which can be from several hundred degrees Celsius to several thousand degrees Celsius, so the salt phase change material has large phase change latent heat and good stability.

[0047] In one embodiment, the pipe diameter of the heat exchange pipeline 2 is maintained unchanged, and the size of the fin gradually decreases from the end of the gradually expanding channel 1 to the end of the gradually contracting channel 6. Figure 4 The schematic diagram of the cross section of the finned heat exchange pipeline according to the embodiment of the present application is shown schematically. As shown in Figure 4 The heat exchange pipeline can be a finned heat exchange pipe, a corresponds to the cross section of the finned heat exchange pipeline at the end of the gradually expanding channel, and b corresponds to the cross section of the finned heat exchange pipeline at the end of the gradually contracting channel. The pipe diameter of the heat exchange pipeline is maintained unchanged, and the size of the fin gradually decreases from the end of the gradually expanding channel to the end of the gradually contracting channel.

[0048] In one embodiment, the material of the heat exchange pipeline 2 can be non-ferrous metal, which can include copper and aluminum. The copper heat exchange pipeline has high electrical conductivity, good flexibility and plasticity, and the thermal conductivity coefficient can reach 398 w / mk, which can adapt to the heat exchange environment with very large heat flux density. The aluminum heat exchange pipeline has high thermal conductivity, large heat transfer capacity and small resistance loss, and has good heat transfer performance. The heat exchange pipeline has high thermal conductivity and good isothermality, and the working personnel can select the appropriate heat exchange pipeline according to the actual work needs.

[0049] In one embodiment, the structure of the phase change heat storage system can be a shell and tube type. The shell and tube type structure can improve the heat release coefficient inside and outside the tube, and the use of the shell and tube type structure makes the structure of the phase change heat storage system more compact, which can save materials and cost. The materials of the three-dimensional bearing support, the shaft, the gradually expanding channel, the gradually contracting channel, the shell, the top cover and the bottom cover of the phase change heat storage system are any one of metal materials. Metal material refers to a material with luster, ductility, easy electrical conductivity and convenient heat transfer. Metal materials can generally be divided into black metal materials and non-ferrous metal materials. Among them, the materials of the three-dimensional bearing support, the shaft, the gradually expanding channel, the gradually contracting channel, the shell, the top cover and the bottom cover of the phase change heat storage system can select stainless steel, steel or other metal materials.

[0050] Figure 5 The schematic diagram of the vertical cross section of the three-dimensional bearing support according to the embodiment of the present application is shown schematically. As shown in Figure 5As shown, the three-dimensional bearing support 8 and the buffer device 7 need to be opened to place the fluid transportation pipeline, which can improve the heat transfer fluid for the entire phase change heat storage system, and the three-dimensional bearing support 8 and the buffer device 7 can provide support for the rotating shaft and the shell. Among them, the buffer device 7 can select a rubber pad, which is a pad made of rubber, which can play the roles of gasket, sealing, buffering, etc. The rubber pad can include transparent adhesive pad, EVA adhesive pad, rubber pad, semi-spherical adhesive pad, etc.

[0051] In one embodiment, the stepper motor can drive the rotating shaft to rotate to realize the turnover of the energy storage unit during the heat storage and / or heat release process, and the turnover angle is 0-180°. Figure 6 The schematic diagram of the heat transfer fluid inlet and outlet according to the embodiment of the present application is schematically shown. As shown Figure 6 As shown, during heat storage, the gradually expanding channel 1 is at the upper end, and the gradually tapering channel 6 is at the lower end. The high-temperature heat transfer fluid 11 flows into the shell 5 from the gradually expanding channel 1, and the heat is transferred to the phase change material 3 in the form of convection and conduction, the phase change material 3 absorbs heat and changes from solid to liquid, storing heat. The inlet temperature of the high-temperature heat transfer fluid 11 entering the energy storage unit and the outlet temperature of the high-temperature heat transfer fluid 11 flowing out of the energy storage unit can be measured by the temperature sensor. In the case where the difference between the inlet temperature value and the outlet temperature value is less than the preset threshold value, it can be determined that the heat storage is completed, the connection valve between the fluid inlet end and the outlet end and the heat transfer pipeline is disconnected, and finally the rotating shaft is rotated by the stepper motor to turn over the energy storage unit. The turnover angle can be 0-180°.

[0052] For example, the temperature sensor measures that the inlet temperature of the high-temperature heat transfer fluid 11 entering the energy storage unit is 240℃, and the outlet temperature of the high-temperature heat transfer fluid 11 flowing out of the energy storage unit is 239.8℃, and the difference between the inlet temperature value and the outlet temperature value is 0.2℃. 0.2℃ is less than the preset position threshold value 0.5℃, which can determine that the heat storage is completed. The connection valve between the fluid inlet end and the outlet end and the heat transfer pipeline is disconnected, and finally the rotating shaft is rotated by the stepper motor to turn over the energy storage unit by 180°.

[0053] During heat release, the gradually tapering channel 6 is at the upper end, and the gradually expanding channel 1 is at the lower end. The low-temperature heat transfer fluid 12 flows into the shell 5 from the gradually expanding channel 1, and the heat is transferred to the low-temperature heat transfer fluid 12 in the form of convection and conduction, and the phase change material 3 releases heat and changes from liquid to solid to release heat. The inlet temperature of the low-temperature heat transfer fluid 12 entering the energy storage unit and the outlet temperature of the low-temperature heat transfer fluid 12 flowing out of the energy storage unit can be measured by the temperature sensor. In the case where the difference between the inlet temperature value and the outlet temperature value is less than the preset threshold value, it can be determined that the heat release is completed, the connection valve between the fluid inlet end and the outlet end and the heat transfer pipeline is disconnected, and finally the rotating shaft is rotated by the stepper motor to turn over the energy storage unit. The turnover angle can be 0-180°.

[0054] For example, the temperature sensor measures that the inlet temperature of the low-temperature heat exchange fluid 12 entering the energy storage unit is 59°C, and the outlet temperature of the low-temperature heat exchange fluid 12 flowing out of the energy storage unit is 59.2°C, and the difference between the inlet temperature value and the outlet temperature value is 0.2°C. 0.2°C is less than the preset position threshold 0.5°C, and it can be determined that the heat release is completed. The connection valve between the fluid inlet end and the outlet end and the heat exchange pipeline is disconnected, and finally the rotating shaft is rotated by the stepping motor to overturn the energy storage unit by 180°.

[0055] In one embodiment, the variable heat storage system further comprises a temperature sensor. The temperature sensor can be used to measure the inlet temperature of the heat exchange fluid entering the energy storage unit and the outlet temperature of the heat exchange fluid flowing out of the energy storage unit; wherein, during heat storage, if the temperature difference between the inlet temperature and the outlet temperature is less than the preset temperature threshold, it is determined that the heat storage is completed, the connection valve between the fluid inlet end and the outlet end and the heat exchange pipeline is disconnected, and the mechanical operation is reversed, the rotating shaft is rotated by the stepping motor to overturn the entire energy storage unit by 180°, and the connection valve is reconnected with the fluid inlet end and the outlet end; during heat release, if the temperature difference between the inlet temperature and the outlet temperature is less than the preset temperature threshold, it is determined that the heat release is completed, the connection valve between the fluid inlet end and the outlet end and the heat exchange pipeline is disconnected, and the mechanical operation is reversed, the rotating shaft is rotated by the stepping motor to overturn the entire energy storage unit by 180°, and the connection valve is reconnected with the fluid inlet end and the outlet end.

[0056] For example, during heat storage, the temperature sensor measures that the inlet temperature of the high-temperature heat exchange fluid entering the energy storage unit is 412°C, and the outlet temperature of the high-temperature heat exchange fluid flowing out of the energy storage unit is 411.6°C. The temperature difference between the inlet temperature and the outlet temperature is 0.4°C, which is less than the preset temperature threshold 0.5°C. It is determined that the heat storage is completed, the connection valve between the fluid inlet end and the outlet end and the heat exchange pipeline is disconnected, and the mechanical operation is reversed, the rotating shaft is rotated by the stepping motor to overturn the entire energy storage unit by 180°, and the connection valve is reconnected with the fluid inlet end and the outlet end. During heat release, the temperature sensor measures that the inlet temperature of the low-temperature heat exchange fluid entering the energy storage unit is 42°C, and the outlet temperature of the low-temperature heat exchange fluid flowing out of the energy storage unit is 43.1°C. The temperature difference between the inlet temperature and the outlet temperature is 0.1°C, which is less than the preset temperature threshold 0.5°C. It is determined that the heat release is completed, the connection valve between the fluid inlet end and the outlet end and the heat exchange pipeline is disconnected, and the mechanical operation is reversed, the rotating shaft is rotated by the stepping motor to overturn the entire energy storage unit by 180°, and the connection valve is reconnected with the fluid inlet end and the outlet end.

[0057] In one embodiment, the reversible circular cone type phase change heat storage system can include an energy storage unit, a fluid transportation channel, and a reversing mechanism. Figure 7The structure block diagram of the reversible truncated cone type phase change heat storage system according to the embodiment of the present application is schematically shown. As shown in Figure 7 The reversible truncated cone type phase change heat storage system 700 includes an energy storage unit 701, a fluid transport channel 702 and a turnover mechanism 703, wherein:

[0058] The energy storage unit 701 includes a thermal insulation material, a shell and a phase change material, and is used for storing and releasing heat of the system, wherein the thermal insulation material is wrapped outside the shell, and the phase change material is uniformly filled between the shell and the heat exchange pipeline;

[0059] The fluid transport channel 702 is located inside the energy storage unit, and includes a diverging channel, a converging channel and a heat exchange pipeline, and is used for providing heat for the energy storage unit, wherein the heat exchange pipeline is uniformly distributed inside the shell, and the diverging channel and the converging channel are located on both sides of the shell;

[0060] The turnover mechanism 703 is connected with the energy storage unit, and includes a rotating shaft, a buffer device, a three-dimensional bearing support and a stepping motor, and is used for turning over the energy storage unit during heat storage and release, so that the energy storage unit stores and releases heat at a preset rate, wherein the three-dimensional bearing support is connected with the rotating shaft, the buffer device is located at the bottom of the energy storage unit, the three-dimensional bearing support and the buffer device provide support for the rotating shaft and the shell, the stepping motor is connected with the rotating shaft, the rotating shaft is connected with the shell, and the stepping motor drives the rotating shaft to rotate to realize the turnover of the energy storage unit during heat storage and / or heat release.

[0061] The ratio of the first bottom diameter and the second bottom diameter of the shell is 1.2-1.4. The cross section of the diverging channel and the converging channel is always a central cross section. The heat exchange pipeline is a heat exchange pipeline with fins, and the pipe diameter of the heat exchange pipeline is maintained unchanged, and the size of the fins gradually decreases from the diverging channel end to the converging channel end. The structure of the reversible truncated cone type phase change heat storage system is a shell and tube type, which can improve the heat release coefficient inside and outside the tube, and the shell and tube structure makes the structure of the phase change heat storage system more compact, which can save materials and cost.

[0062] In the heat storage process, the diverging channel is at the upper end, and the high-temperature heat exchange fluid flows into the shell from the diverging channel (i.e., the high-temperature heat exchange fluid enters the energy storage unit through the inlet with a diameter of R). The heat is transferred to the phase change material by the heat exchange pipeline in the form of convection and heat conduction. The phase change material absorbs heat and changes from solid to liquid, storing heat. The converging channel is at the lower end, and the high-temperature heat exchange fluid flows out of the shell from the converging channel (i.e., the high-temperature heat exchange fluid flows out of the energy storage unit through the outlet with a diameter of r). The inlet temperature and the outlet temperature of the high-temperature heat exchange fluid entering and flowing out of the energy storage unit are measured by the temperature sensor. The inlet temperature value measured by the temperature sensor is 240℃, and the outlet temperature value is 239.8℃, obtaining a difference between the inlet temperature value and the outlet temperature value of 0.2℃. 0.2℃ is less than the preset position threshold value of 0.5℃, and it can be determined that the heat storage is completed. The connection valve between the fluid inlet end and the outlet end and the heat exchange pipeline is disconnected, the energy storage unit is turned over by 180° by rotating the rotating shaft driven by the stepping motor in the overturning machine, and the connection valve is connected with the fluid inlet end and the outlet end again.

[0063] In the heat release process, the diverging channel is at the lower end, and the low-temperature heat exchange fluid flows into the shell from the diverging channel (i.e., the low-temperature heat exchange fluid enters the energy storage unit through the inlet with a diameter of R). The heat is transferred to the low-temperature heat exchange fluid by the heat exchange pipeline in the form of convection and heat conduction. The phase change material absorbs heat and changes from liquid to solid, releasing heat. The converging channel is at the upper end, and the low-temperature heat exchange fluid flows out of the shell from the converging channel (i.e., the low-temperature heat exchange fluid flows out of the energy storage unit through the outlet with a diameter of r). The inlet temperature and the outlet temperature of the low-temperature heat exchange fluid entering and flowing out of the energy storage unit are measured by the temperature sensor. The inlet temperature value measured by the temperature sensor is 59℃, and the outlet temperature value is 59.2℃, obtaining a difference between the inlet temperature value and the outlet temperature value of 0.2℃. 0.2℃ is less than the preset position threshold value of 0.5℃, and it can be determined that the heat release is completed. The connection valve between the fluid inlet end and the outlet end and the heat exchange pipeline is disconnected, and finally the energy storage unit is turned over by 180° by rotating the rotating shaft driven by the stepping motor, and the connection valve is connected with the fluid inlet end and the outlet end again.

[0064] Through the above technical solution, the heat of the reversible circular cone type phase change heat storage system is stored and released by the energy storage unit; the fluid transportation channel can provide heat for the energy storage unit; the overturning machine, connected with the energy storage unit, can overturn the energy storage unit during the heat storage and release process, so that the diverging channel is at the upper end and the converging channel is at the lower end during heat storage, and the converging channel is at the upper end and the diverging channel is at the lower end during heat release. The technical solution can ensure that the heat storage and release rates of the phase change heat storage system are consistent, solve the problem of uneven heat exchange caused by natural convection, and significantly improve the heat exchange performance of the phase change heat storage system.

[0065] It should also be noted that the terms "comprising", "comprises" or other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0066] The above embodiments are only used to illustrate the present application, but not to limit it. Instead of the above, various modifications and changes can be made to the application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall fall into the scope of the claims of the application.

Claims

1. A reversible cone-shaped phase change thermal storage system, characterized by, The phase change heat storage system comprises: a heat storage unit comprising heat preservation material, a shell and phase change material, for storing and releasing heat of the system, wherein the heat preservation material is wrapped outside the shell, and the phase change material is uniformly filled between the shell and heat exchange pipelines; a fluid transportation channel located inside the heat storage unit, comprising a diverging channel, a converging channel and the heat exchange pipelines, for providing heat for the heat storage unit, wherein the heat exchange pipelines are uniformly distributed inside the shell, and the diverging channel and the converging channel are located on both sides of the shell; a turnover mechanism connected with the heat storage unit, comprising a rotating shaft, a buffer device, a three-dimensional bearing support and a stepping motor, for turning over the heat storage unit during heat storage and release, so that the heat storage unit stores and releases heat at a preset rate, wherein the three-dimensional bearing support is connected with the rotating shaft, the buffer device is located at the bottom of the heat storage unit, the three-dimensional bearing support and the buffer device provide support for the rotating shaft and the shell, the stepping motor is connected with the rotating shaft, the rotating shaft is connected with the shell, and the stepping motor drives the rotating shaft to rotate to realize the turnover of the heat storage unit during heat storage and / or heat release; wherein during heat storage, the diverging channel is at the upper end and the converging channel is at the lower end, high-temperature heat exchange fluid flows into the shell from the diverging channel, heat is transferred to the phase change material in the form of convection and conduction, the phase change material absorbs heat and changes from solid to liquid to store heat; during heat release, the converging channel is at the upper end and the diverging channel is at the lower end, low-temperature heat exchange fluid flows into the shell from the diverging channel, heat is transferred to the low-temperature heat exchange fluid in the form of convection and conduction, and the phase change material releases heat and changes from liquid to solid to release heat.

2. The reversible frustum-type phase change thermal storage system of claim 1, wherein, The cross sections of the diverging channel and the converging channel are always circular.

3. The reversible frustum-type phase change thermal storage system of claim 1, wherein, The heat exchange pipelines are finned heat exchange pipelines, wherein the structure of the fins is any one of snowflake type, spider web type and tree branch type.

4. The reversible frustum-type phase change thermal storage system of claim 3, wherein, The diameter of the heat exchange pipelines remains unchanged, and the size of the fins gradually decreases from the end of the diverging channel to the end of the converging channel.

5. The reversible frustum-type phase change thermal storage system of claim 3, wherein, The material of the heat exchange pipelines is copper or aluminum.

6. The reversible frustum-type phase change thermal storage system of claim 1, wherein, The structure of the phase change heat storage system is shell-and-tube type, and the materials of the three-dimensional bearing support, the rotating shaft, the diverging channel, the converging channel, the shell, the top cover and the bottom cover of the phase change heat storage system are any one of metal materials.

7. The reversible frustum-type phase change thermal storage system of claim 1, wherein, The phase change material is replaced according to the actual heat utilization temperature, and the replaced type is any one of paraffin, alcohol and salt.

8. The reversible frustum-type phase change thermal storage system of claim 1, wherein, The stepping motor drives the rotating shaft to rotate to realize the turnover of the heat storage unit during heat storage and / or heat release, and the turnover angle is 0-180°.

9. The reversible frustum-shaped phase change thermal storage system of claim 1, wherein, The ratio of the first bottom surface diameter R to the second bottom surface diameter r of the shell is 1.2-1.4; wherein during heat storage, R is the circular diameter of the inlet cross section of the high-temperature heat exchange fluid, and r is the circular diameter of the outlet cross section of the high-temperature heat exchange fluid; during heat release, R is the circular diameter of the inlet cross section of the low-temperature heat exchange fluid, and r is the circular diameter of the outlet cross section of the low-temperature heat exchange fluid.

10. The reversible frustum-type phase change thermal storage system of claim 1, wherein, The phase change heat storage system further comprises: a temperature sensor for measuring the inlet temperature of the heat exchange fluid entering the energy storage unit and the outlet temperature of the heat exchange fluid flowing out of the energy storage unit; wherein, during heat storage, if the temperature difference between the inlet temperature and the outlet temperature is less than a preset temperature threshold, it is determined that the heat storage is completed, the connection valve between the fluid inlet end and the outlet end and the heat exchange pipeline is disconnected, and the mechanical operation is reversed, the rotation shaft is driven to rotate by the stepping motor to overturn the entire energy storage unit by 180°, and the connection valve is reconnected with the fluid inlet end and the outlet end; during heat release, if the temperature difference between the inlet temperature and the outlet temperature is less than the preset temperature threshold, it is determined that the heat release is completed, the connection valve between the fluid inlet end and the outlet end and the heat exchange pipeline is disconnected, and the mechanical operation is reversed, the rotation shaft is driven to rotate by the stepping motor to overturn the entire energy storage unit by 180°, and the connection valve is reconnected with the fluid inlet end and the outlet end.

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