Double-channel shell-and-tube phase change heat accumulator and heat exchange method thereof

Abstract

The invention provides a double-channel shell-and-tube phase change heat accumulator and a heat exchange method thereof. Comprising a heat accumulator shell and a tube plate fixedly installed on the inner surface of the heat accumulator shell, and a heat accumulation fluid heat exchange tube and a heat release fluid heat exchange tube which are fixedly connected with the tube plate are arranged on an inner cavity where the inner surface of the heat accumulator shell is located. A heat storage fluid inlet connecting pipe, a heat storage fluid outlet connecting pipe, a heat release fluid inlet connecting pipe and a heat release fluid outlet connecting pipe which are communicated with the interior of the heat accumulator shell are arranged outside the heat accumulator shell; the heat storage fluid heat exchange pipe, the heat storage fluid inlet connecting pipe and the heat storage fluid outlet connecting pipe form a heat storage fluid flow channel; and the heat release fluid heat exchange tube, the heat release fluid inlet connecting tube and the heat release fluid outlet connecting tube form a heat release fluid flow channel. A double-flow-channel structure is adopted, heat storage fluid and heat release fluid independently flow in different flow channels, direct mixing or mutual interference of the two kinds of fluid in the heat exchange process is avoided, and therefore the stability and efficiency of heat transfer are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal energy storage and conversion, and in particular to a double-channel shell and tube phase change heat accumulator and a heat exchange method thereof. Background Art

[0002] With the continuous growth of global energy consumption and the rapid expansion of renewable energy utilization, how to efficiently store and utilize thermal energy has become one of the key challenges that need to be urgently addressed in the field of energy technology. Latent heat storage systems have attracted widespread attention due to their high heat storage density, small temperature fluctuations during phase change processes, and strong controllability. They have shown great application potential in the fields of building energy conservation, solar energy utilization, heat pump water heaters, battery thermal management, and industrial waste heat recovery. Among them, the latent heat storage system based on PCM (Phase Change Material) is particularly significant. It absorbs or releases a large amount of latent heat during the phase transition process of phase change materials, thereby achieving efficient storage and transfer of energy.

[0003] In these latent heat storage systems, the phase change heat storage device is the core heat exchange equipment, and its heat exchange performance directly affects the heat storage and heat release rate of the system and the overall operating efficiency. In the prior art, shell and tube heat storage devices are widely used in the field of phase change heat storage due to their advantages such as large heat transfer area, stable structure and wide application range.

[0004] At present, the prior art discloses a detachable shell and tube phase change heat storage and heat exchange unit, whose structure includes a shell, an end cover, an annular sleeve and a heating rod. One end of the shell is provided with an opening that matches the end cover, and the end cover is fixedly installed at the opening of the shell. The annular sleeve is located inside the shell and connected to the end cover, and its interlayer is filled with phase change material. The heating rod is located inside the annular sleeve and is used to convert electrical energy into thermal energy and store heat in the phase change material in the annular sleeve. The shell is provided with a fluid inlet and a fluid outlet so that the fluid can enter and leave the shell, thereby realizing efficient heat exchange with the phase change material.

[0005] The disadvantages of the detachable shell-and-tube phase-change heat storage and heat exchange unit in the above-mentioned prior art include: the shell-and-tube phase-change heat storage and heat exchange unit adopts a single-channel structure design. Although the phase change heat storage device with a single-channel structure is simple in design, it has significant shortcomings. First, the heat exchange efficiency is low. Since the heat storage fluid and the heat release fluid share the same channel, it is easy to mix or interfere during the heat exchange process, resulting in unstable heat transfer. Especially when the temperature difference gradually decreases, the heat exchange rate drops significantly, and it is difficult to achieve precise temperature control. Secondly, the heat transfer rate is limited because the fluid path of the single-channel structure cannot be optimized, the contact area between the fluid and the phase change material is limited, the heat transfer path is long, and the overall heat exchange is slow. In addition, the fluid flow distribution may be uneven, further affecting the heat transfer effect. Most importantly, the single-channel structure performs poorly under multi-media conditions. Heat storage and heat release fluids are usually different media with their own physical properties, but the single channel cannot flexibly cope with these differences, which may lead to unstable flow and reduce heat exchange efficiency. In addition, the shared flow channel limits the system's adaptability under changing working conditions and makes it difficult to operate efficiently when switching modes quickly, which seriously affects the flexibility of energy management and overall performance. Summary of the invention

[0006] The embodiments of the present invention provide a double-channel shell and tube phase-change heat accumulator and a heat exchange method thereof, so as to effectively improve the heat storage and heat exchange efficiency of the shell-type phase-change heat accumulator.

[0007] In order to achieve the above object, the present invention adopts the following technical scheme.

[0008] According to one aspect of the present invention, a double-channel shell and tube phase change heat accumulator is provided, comprising: a heat accumulator shell (7), and a tube sheet (8) fixedly mounted on the inner surface of the heat accumulator shell (7); a heat storage fluid heat exchange tube (10) and a heat release fluid heat exchange tube (11) fixedly connected to the tube sheet (8) are arranged on the inner cavity where the inner surface of the heat accumulator shell (7) is located; and a heat storage fluid inlet pipe (1), a heat storage fluid outlet pipe (2), a heat release fluid inlet pipe (3) and a heat release fluid outlet pipe (4) are arranged on the outside of the heat accumulator shell (7) and are connected to the inside of the heat accumulator shell (7);

[0009] The heat storage fluid heat exchange pipe (10), the heat storage fluid inlet pipe (1) and the heat storage fluid outlet pipe (2) form a heat storage fluid flow channel; the heat release fluid heat exchange pipe (11), the heat release fluid inlet pipe (3) and the heat release fluid outlet pipe (4) form a heat release fluid flow channel.

[0010] Preferably, the heat storage fluid heat exchange tube (10) and the heat release fluid heat exchange tube (11) are arranged in the form of an equilateral triangle in the longitudinal cross section of the internal cavity, and the spacing between adjacent heat exchange tubes is equal.

[0011] Preferably, the heat storage fluid heat exchange tubes (10) and the heat release fluid heat exchange tubes (11) are arranged alternately in the internal cavity.

[0012] Preferably, the heat storage fluid heat exchange tube (10), the heat release fluid heat exchange tube (11) and the tube sheet (8) are fixedly connected by expansion joint or welding, and the tube sheet (8) is fixed to the inner surface of the heat accumulator shell (7) by welding or bolting.

[0013] Preferably, two tube sheets (8) are respectively arranged at the left and right ends of the internal cavity, and the two tube sheets (8) are used to fix the heat storage fluid heat exchange tubes (10);

[0014] Two tube sheets (8) are arranged at the middle left and middle right positions of the internal cavity, and the two tube sheets (8) are used to fix heat exchanging tubes (11) of heat releasing fluid.

[0015] Preferably, the heat storage fluid inlet pipe (1) and the heat storage fluid outlet pipe (2) are respectively located at the leftmost and rightmost sides of the heat storage shell (7); the heat release fluid inlet pipe (3) and the heat release fluid outlet pipe (4) are respectively located at the middle right and middle left positions of the heat storage shell.

[0016] Preferably, an automatic exhaust valve (5) is arranged on the upper side of the heat accumulator housing (7), and the automatic exhaust valve (5) is used to balance the internal and external air pressures.

[0017] Preferably, a filling port (6) is provided on the upper side of the heat accumulator shell (7), and the filling port (6) is communicated with the inside of the heat accumulator shell (7) for filling the phase change material.

[0018] According to another aspect of the present invention, a heat exchange method of a double-channel shell and tube phase change heat accumulator is provided, comprising:

[0019] During the heat storage stage, the externally heated heat storage fluid enters the heat accumulator shell from the heat storage fluid inlet pipe, and the heat storage fluid flows along the heat storage fluid heat exchange tubes. The heat exchange tubes are evenly distributed in the inner cavity of the heat accumulator and are in direct contact with the phase change material. The high temperature of the heat storage fluid transfers heat to the phase change material through the tube wall of the heat exchange tube. The phase change material absorbs heat and gradually changes from solid to liquid, completing the phase change heat storage process.

[0020] Preferably, in the heat release stage, the externally cooled heat release fluid enters the heat accumulator shell from the heat release fluid inlet pipe and flows along the heat release fluid heat exchange pipe. The heat stored in the phase change material in the previous stage is gradually transferred to the heat release fluid flowing through the pipe wall of the heat release fluid heat exchange pipe. After releasing the heat, the phase change material gradually recovers from the liquid state to the solid state, completing the phase change heat release process. After the hot fluid absorbs the heat, the temperature gradually rises and is discharged from the heat release fluid outlet pipe.

[0021] The diameters of the heat storage fluid inlet pipe, the heat storage fluid outlet pipe, the heat release fluid inlet pipe, the heat release fluid outlet pipe, the heat storage fluid heat exchange pipe, and the heat release fluid heat exchange pipe vary according to the fluid medium.

[0022] It can be seen from the technical solutions provided by the above embodiments of the present invention that the double-channel shell and tube phase change heat accumulator of the present invention is compact and reasonable, adopts a double-channel design, and is suitable for multiple fields such as building energy conservation, solar energy utilization, and industrial waste heat recovery.

[0023] Additional aspects and advantages of the present invention will be given in part in the following description, which will become obvious from the following description, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic structural diagram of a double-channel shell and tube phase change heat accumulator provided in an embodiment of the present invention;

[0025] Figure 2 It is a transverse cross-sectional view of a double-channel shell and tube phase change heat accumulator provided by the present invention;

[0026] Figure 3 It is a longitudinal cross-sectional view of a double-channel shell and tube phase change heat accumulator provided by the present invention;

[0027] Figure 4 It is a schematic diagram of fluid flow in a heat storage state of a double-channel shell and tube phase change heat accumulator provided by the present invention;

[0028] Figure 5 It is a schematic diagram of fluid flow in a heat release state of a double-channel shell and tube phase change heat accumulator provided by the present invention.

[0029] The meaning of each symbol in the accompanying drawings:

[0030] 1. Heat storage fluid inlet pipe; 2. Heat storage fluid outlet pipe; 3. Heat release fluid inlet pipe; 4. Heat release fluid outlet pipe; 5. Automatic exhaust valve; 6. Filling port; 7. Heat accumulator shell; 8. Tube sheet; 9. Phase change material; 10. Heat storage fluid heat exchange tube; 11. Heat release fluid heat exchange tube. DETAILED DESCRIPTION

[0031] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention.

[0032] It will be understood by those skilled in the art that, unless expressly stated, the singular forms "one", "said", and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that when we refer to an element as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be intermediate elements. In addition, the "connection" or "coupling" used herein may include wireless connection or coupling. The term "and / or" used herein includes any unit and all combinations of one or more associated listed items.

[0033] In the description of this patent, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing this patent and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this patent.

[0034] In the description of this patent, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "set" should be understood in a broad sense, for example, it can be fixedly connected or set, or it can be detachably connected or set, or connected or set in one piece. For ordinary technicians in this field, the specific meanings of the above terms in this patent can be understood according to specific circumstances.

[0035] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0036] To facilitate understanding of the embodiments of the present invention, several specific embodiments will be further explained below with reference to the accompanying drawings, and each embodiment does not constitute a limitation on the embodiments of the present invention.

[0037] In the description of this patent, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing this patent and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this patent.

[0038] In the description of this patent, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "set" should be understood in a broad sense, for example, it can be fixedly connected or set, or it can be detachably connected or set, or connected or set in one piece. For ordinary technicians in this field, the specific meanings of the above terms in this patent can be understood according to specific circumstances.

[0039] The present invention provides a structural schematic diagram of a double-channel shell and tube phase change heat accumulator as shown in Figure 1 As shown, the cross-sectional view is Figure 2 As shown, the longitudinal cross-sectional view is Figure 3 As shown. It includes a heat accumulator shell 7, a heat storage fluid heat exchange tube 10, a heat release fluid heat exchange tube 11 and a tube sheet 8. The heat accumulator shell 7 is cylindrical as a whole, and is provided with a heat storage fluid inlet pipe 1, a heat storage fluid outlet pipe 2, a heat release fluid inlet pipe 3 and a heat release fluid outlet pipe 4 which are connected to the inside of the heat accumulator shell 7. These pipes are respectively connected to the external pipeline system to realize the inlet and outlet of the heat storage fluid and the heat release fluid.

[0040] The tube sheet 8 is fixedly mounted on the inner surface of the heat accumulator shell 7, and a heat storage fluid heat exchange tube 10 and a heat release fluid heat exchange tube 11 fixedly connected to the tube sheet 8 are arranged on the inner cavity where the inner surface of the heat accumulator shell 7 is located. The heat storage fluid heat exchange tube 10, the heat storage fluid inlet pipe 1 and the heat storage fluid outlet pipe 2 constitute a heat storage fluid flow channel; the heat release fluid heat exchange tube 11, the heat release fluid inlet pipe 3 and the heat release fluid outlet pipe 4 constitute a heat release fluid flow channel.

[0041] In actual application, the heat storage fluid inlet pipe 1 and the heat storage fluid outlet pipe 2 are respectively located at the leftmost and rightmost sides of the heat storage shell 7, and the heat storage fluid inlet pipe 1 and the heat storage fluid outlet pipe 2 are connected to the inside of the heat storage shell 7 for heat storage of the heat storage fluid. The heat release fluid inlet pipe 3 and the heat release fluid outlet pipe 4 are respectively located at the middle right and middle left positions of the heat storage shell 7, and the heat release fluid inlet pipe 3 and the heat release fluid outlet pipe 4 are connected to the inside of the heat storage shell for heat release of the heat release fluid.

[0042] The heat storage fluid heat exchange tube 10 and the heat release fluid heat exchange tube 11 are arranged in a regular triangle on the longitudinal cross section of the internal cavity of the above-mentioned heat accumulator. This arrangement makes the spacing between adjacent heat exchange tubes equal, which not only increases the contact area between the heat exchange tube and the phase change material, but also promotes the uniform distribution of heat in the phase change material.

[0043] The tube sheet 8 is fixed to the inner surface of the heat accumulator shell 7 by welding or bolting to ensure the stability and sealing of the overall structure. During the assembly process, the edge of the tube sheet 8 and the end of the heat accumulator shell 7 can be precisely welded to form a reliable connection to prevent fluid leakage. In addition, in order to facilitate installation and maintenance, a flange connection method can also be adopted, by setting a flange at the connection between the tube sheet and the heat accumulator shell, and tightening it with bolts, and setting a sealing gasket between the connection surfaces to ensure sealing performance.

[0044] The tube sheet 8 is fixedly connected to the heat storage fluid heat exchange tube 10 and the heat release fluid heat exchange tube 11. The heat exchange tube is fixed through the tube sheet 8. The tube sheet structure ensures the stable installation of the heat exchange tube to prevent fluid leakage. The heat storage fluid heat exchange tube 10, the heat release fluid heat exchange tube 11 and the tube sheet 8 are usually fixed by expansion or welding. The welding method can form a firm seal between the tube sheet 8 and the heat exchange tube. The expansion method mechanically expands the heat exchange tube to make it in close contact with the tube sheet 8 to form a seal. Both methods can prevent leakage of heat storage and heat release fluids.

[0045] The material of the heat accumulator shell 7 needs to take into account strength, heat resistance and corrosion resistance to meet the use requirements of the device under different working conditions. In general, the shell is made of carbon steel, stainless steel (such as 304 or 316L) or alloy steel. Carbon steel is suitable for mild working conditions and has a high cost performance; stainless steel has good corrosion resistance and high heat resistance, and is suitable for application environments containing corrosive media or high temperatures; alloy steel can provide excellent mechanical strength and durability under extreme high temperature and high pressure conditions, and is suitable for more demanding industrial scenarios. The material selection needs to be comprehensively considered in combination with the medium characteristics and operating temperature.

[0046] The material of the tube sheet 8 needs to match that of the heat accumulator shell 7 to avoid thermal stress at the joint due to differences in thermal expansion coefficients. It also needs to have good corrosion resistance and mechanical strength. Common materials include stainless steel, carbon steel, and copper alloys. Among them, stainless steel tube sheets have excellent corrosion resistance and are ideal for corrosive media and high temperature conditions; carbon steel tube sheets are suitable for non-corrosive environments and have high strength and economy; copper alloy tube sheets have good thermal conductivity and are often used in low-pressure or fast heat transfer systems. In application, a reasonable choice must be made based on the properties, pressure, and temperature of the heat exchange medium.

[0047] The heat storage fluid heat exchange tube 10 and the heat release fluid heat exchange tube 11 are the core heat exchange components of the heat accumulator, and their materials directly affect the heat transfer efficiency and system life. Common materials include stainless steel, copper, carbon steel and alloy steel. Stainless steel heat exchange tubes are suitable for a variety of high temperature, high pressure or corrosive fluid scenarios due to their strong corrosion resistance; copper heat exchange tubes have good thermal conductivity and are suitable for low pressure or non-corrosive medium environments; carbon steel heat exchange tubes have high strength and good economy, but weak corrosion resistance and are only suitable for mild working conditions; alloy steel heat exchange tubes can exhibit excellent mechanical properties in high temperature or high pressure applications. The material of the heat exchange tube must be optimized taking into account the medium characteristics, heat transfer requirements and service life, and ensure compatibility with phase change materials.

[0048] like Figure 2 As shown, in actual applications, the heat storage fluid heat exchange tubes 10 and the heat release fluid heat exchange tubes 11 arranged in the internal cavity of the heat accumulator can be arranged alternately, the pipes passed by the dotted line are the heat storage fluid heat exchange tubes 10, and the pipes passed by the dotted line are the heat release fluid heat exchange tubes 11, which further optimizes the fluid path and makes heat transfer more efficient.

[0049] like Figure 3 As shown, in actual application, the tube sheets 8 are respectively located on both sides of the internal cavity of the heat accumulator, and there are two tube sheets on each side. The leftmost and rightmost tube sheets are used to fix the heat storage fluid heat exchange tubes 10 to form a heat storage fluid flow channel. And the heat storage fluid heat exchange tubes 10 are longer than the heat release fluid heat exchange tubes 11. The heat release fluid heat exchange tubes 11 are slightly shorter and are fixed on the tube sheet near the middle to form a heat release fluid flow channel.

[0050] The diameters of the heat storage fluid inlet pipe, the heat storage fluid outlet pipe, the heat release fluid inlet pipe, the heat release fluid outlet pipe, the heat storage fluid heat exchange pipe, and the heat release fluid heat exchange pipe can be changed according to the fluid medium. When the heat storage fluid or the heat release fluid is a gas or a phase change occurs during the heat exchange process, the pipe and the heat exchange pipe can be selected with appropriate pipe diameters to meet the flow requirements of different fluid media;

[0051] The diameters of the heat storage fluid heat exchange tubes and the heat release fluid heat exchange tubes can be the same or different. The diameter of each heat exchange tube can range from 4 to 50 mm, and the tube center distance is 5 to 65 mm, which can be adjusted according to the required heat exchange area or actual fluid medium.

[0052] An automatic exhaust valve 5 is also provided on the upper side of the heat accumulator shell 7. The automatic exhaust valve 5 is used to balance the internal and external air pressures to prevent the phase change material from being unable to completely fill the heat accumulator due to residual gas in the heat accumulator shell. The automatic exhaust valve 5 can balance the air pressure inside and outside the heat accumulator shell 7, and automatically exhaust residual gas when the phase change material is filled or during the heat exchange process, ensuring that there is no air barrier inside, thereby improving the contact efficiency between the phase change material and the heat exchange tube.

[0053] A filling port 6 is also provided on the upper side of the heat accumulator shell 7, and the filling port 6 is communicated with the inside of the heat accumulator shell 7. During the first use and maintenance of the heat accumulator, the filling port (6) is used to fill the phase change material (composite phase change material with expanded graphite added) to ensure that the phase change material flows into the inside of the heat accumulator and closely contacts the heat exchange tubes, so as to achieve efficient heat exchange.

[0054] The inner cavity of the double-channel shell-and-tube phase-change heat accumulator is filled with a phase-change material 9, which completely wraps the heat exchange tube and is a composite phase-change material with expanded graphite added, with a thermal conductivity of 1W / (m·K), which has both high thermal conductivity and fluidity. The air inside the heat accumulator shell is discharged through an automatic exhaust valve 5 to ensure that the phase-change material can completely fill the entire inner cavity.

[0055] The heat storage fluid and the heat release fluid in the double-channel shell-and-tube phase-change heat accumulator in the embodiment of the present invention flow separately, and stable heat energy storage and release are achieved through independent fluid paths, which is particularly suitable for application scenarios that require precise temperature control and frequent heat energy conversion. The specific working process of the double-channel shell-and-tube phase-change heat accumulator in the embodiment of the present invention is as follows:

[0056] Figure 4 The figure is a schematic diagram of the fluid flow in the heat storage state of a double-channel shell and tube phase change heat accumulator provided by the present invention. The heat storage process of the double-channel shell and tube phase change heat accumulator includes:

[0057] like Figure 4 As shown, in the heat storage stage, the externally heated heat storage fluid (such as high-temperature hot oil or hot water) enters the heat accumulator shell 7 from the heat storage fluid inlet pipe 1. The heat storage fluid flows along the heat storage fluid heat exchange tube 10, which is evenly distributed in the inner cavity of the heat accumulator and directly contacts the phase change material 9. At this time, the high temperature of the heat storage fluid transfers heat to the phase change material 9 through the tube wall of the heat exchange tube. The phase change material 9 absorbs heat and gradually changes from solid to liquid, completing the phase change heat storage process. In this process, the phase change material 9 can absorb and store a large amount of latent heat, ensuring that the heat accumulator has a high energy density. Through the large-area contact between the heat storage fluid heat exchange tube and the phase change material, heat is transferred rapidly and evenly, reducing thermal resistance and improving heat storage efficiency. After the heat storage fluid flows through the entire heat exchange tube system and releases most of the heat, the heat storage fluid with a reduced temperature flows out from the heat storage fluid outlet pipe 2, completing the heat storage stage.

[0058] Figure 5 Schematic diagram of fluid flow in a heat release state of a double-channel shell and tube phase change heat accumulator provided by the present invention. The heat release process of the double-channel shell and tube phase change heat accumulator includes:

[0059] like Figure 5As shown, in the heat release stage, the externally cooled heat release fluid (such as cold water or cooling gas) enters the heat accumulator shell from the heat release fluid inlet pipe 3 and flows along the heat release fluid heat exchange tube 11. At this time, the heat stored in the phase change material 9 in the previous stage will be gradually transferred to the heat release fluid flowing through the tube wall of the heat release fluid heat exchange tube 11. After releasing heat, the phase change material 9 gradually recovers from liquid to solid, completing the phase change heat release process. After the hot fluid absorbs heat, the temperature gradually rises and is discharged from the heat release fluid outlet pipe 4. Through the optimized arrangement of the heat exchange tubes, the heat distribution is more uniform, and the heat release process is more stable and efficient.

[0060] The entire heat release process utilizes a dual-channel design, which allows the heat storage and heat release processes to operate independently, avoiding fluid mixing or temperature interference, thereby ensuring efficient operation of the system.

[0061] In summary, in order to overcome the problem of low thermal conductivity of phase change materials, the device of the present invention adds expanded graphite or other high thermal conductivity materials to the phase change material, so that heat can be transferred more quickly during the phase change process, local overheating can be reduced, and the overall heat exchange effect can be improved, thereby increasing the heat storage and heat release rates of the phase change heat storage device, making it more suitable for practical applications.

[0062] The dual-channel design of the present invention flexibly distributes fluid paths and can meet the characteristics of heat exchange of various media. In particular, in systems that need to frequently switch between heat storage and heat release modes, the dual-channel structure provides excellent adaptability and improves the flexibility and operating efficiency of overall energy management.

[0063] The present invention adopts a dual-channel structure, so that the heat storage fluid and the heat release fluid flow independently in different channels, avoiding direct mixing or mutual interference of the two fluids during the heat exchange process, thereby significantly improving the stability and efficiency of heat transfer. The heat storage and heat release processes can be independently optimized according to demand, ensuring more precise temperature control during the heat exchange process and meeting the application requirements of multiple working conditions.

[0064] The present invention adopts a shell-and-tube double-channel structure. Compared with other double-channel heat accumulators, it has the unique advantages of large heat transfer area, stable structure and strong adaptability, and can meet the heat exchange of multiphase flow. Its design can provide efficient heat exchange in a limited space, and can withstand high pressure and high temperature conditions to ensure long-term stable operation. In addition, the shell-and-tube structure is easy to integrate and maintain, and can be widely used in a variety of industrial and energy management scenarios.

[0065] Those skilled in the art can understand that the accompanying drawings are only schematic diagrams of an embodiment, and the modules or processes in the accompanying drawings are not necessarily required to implement the present invention.

[0066] Those skilled in the art can understand that the components in the device in the embodiment can be distributed in the device in the embodiment according to the description of the embodiment, or can be changed accordingly and located in one or more devices different from the embodiment. The components in the above embodiment can be combined into one component, or can be further divided into multiple sub-components.

[0067] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A double-channel shell and tube phase change heat accumulator, characterized in that: include: A heat accumulator shell (7), and a tube sheet (8) fixedly mounted on the inner surface of the heat accumulator shell (7); a heat storage fluid heat exchange tube (10) and a heat release fluid heat exchange tube (11) fixedly connected to the tube sheet (8) are arranged on the inner cavity where the inner surface of the heat accumulator shell (7); and a heat storage fluid inlet pipe (1), a heat storage fluid outlet pipe (2), a heat release fluid inlet pipe (3) and a heat release fluid outlet pipe (4) are arranged on the outside of the heat accumulator shell (7) and are connected to the inside of the heat accumulator shell (7); The heat storage fluid heat exchange pipe (10), the heat storage fluid inlet pipe (1) and the heat storage fluid outlet pipe (2) form a heat storage fluid flow channel; the heat release fluid heat exchange pipe (11), the heat release fluid inlet pipe (3) and the heat release fluid outlet pipe (4) form a heat release fluid flow channel.

2. The double-channel shell and tube phase change heat accumulator according to claim 1, characterized in that: The heat storage fluid heat exchange tube (10) and the heat release fluid heat exchange tube (11) are arranged in a regular triangle in the longitudinal cross section of the internal cavity, and the spacing between adjacent heat exchange tubes is equal.

3. The double-channel shell and tube phase change heat accumulator according to claim 2, characterized in that: The heat storage fluid heat exchange tubes (10) and the heat release fluid heat exchange tubes (11) are arranged alternately in the internal cavity.

4. The double-channel shell and tube phase change heat accumulator according to claim 2, characterized in that: The heat storage fluid heat exchange tube (10), the heat release fluid heat exchange tube (11) and the tube sheet (8) are fixedly connected by expansion or welding, and the tube sheet (8) is fixed to the inner surface of the heat accumulator shell (7) by welding or bolt connection.

5. The double-channel shell and tube phase change heat accumulator according to claim 3, characterized in that: Two tube sheets (8) are respectively arranged at the left and right ends of the internal cavity, and the two tube sheets (8) are used to fix the heat storage fluid heat exchange tubes (10); Two tube sheets (8) are arranged at the middle left and middle right positions of the internal cavity, and the two tube sheets (8) are used to fix heat exchanging tubes (11) of heat releasing fluid.

6. The double-channel shell and tube phase change heat accumulator according to claim 3, characterized in that: The heat storage fluid inlet pipe (1) and the heat storage fluid outlet pipe (2) are respectively located at the leftmost and rightmost sides of the heat storage shell (7); the heat release fluid inlet pipe (3) and the heat release fluid outlet pipe (4) are respectively located at the middle right and middle left positions of the heat storage shell.

7. The double-channel shell and tube phase change heat accumulator according to claim 1, characterized in that: An automatic exhaust valve (5) is arranged on the upper side of the heat accumulator shell (7), and the automatic exhaust valve (5) is used to balance the internal and external air pressures.

8. The double-channel shell and tube phase change heat accumulator according to claim 1, characterized in that: A filling port (6) is arranged on the upper side of the heat accumulator shell (7), and the filling port (6) is communicated with the inside of the heat accumulator shell (7) and is used for filling phase change material.

9. A heat exchange method for a double-channel shell and tube phase change heat accumulator, characterized in that: include: During the heat storage stage, the externally heated heat storage fluid enters the heat accumulator shell from the heat storage fluid inlet pipe, and the heat storage fluid flows along the heat storage fluid heat exchange tubes. The heat exchange tubes are evenly distributed in the inner cavity of the heat accumulator and are in direct contact with the phase change material. The high temperature of the heat storage fluid transfers heat to the phase change material through the tube wall of the heat exchange tube. The phase change material absorbs heat and gradually changes from solid to liquid, completing the phase change heat storage process.

10. The heat exchange method of the double-channel shell and tube phase change heat accumulator according to claim 9, characterized in that: include: In the heat release stage, the externally cooled heat release fluid enters the heat accumulator shell from the heat release fluid inlet pipe and flows along the heat release fluid heat exchange pipe. The heat stored in the phase change material in the previous stage is gradually transferred to the heat release fluid flowing through the pipe wall of the heat release fluid heat exchange pipe. After releasing the heat, the phase change material gradually recovers from liquid to solid, completing the phase change heat release process. After the hot fluid absorbs the heat, the temperature gradually rises and is discharged from the heat release fluid outlet pipe. The diameters of the heat storage fluid inlet pipe, the heat storage fluid outlet pipe, the heat release fluid inlet pipe, the heat release fluid outlet pipe, the heat storage fluid heat exchange pipe, and the heat release fluid heat exchange pipe vary according to the fluid medium.

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