Double-pipe heat exchanger and heat pump system

Abstract

The present application relates to heat exchanger technical field, specifically provide a double pipe heat exchanger and heat pump system, aim at solving the existing heat pump system in double pipe heat exchanger for the sake of heating and hot water function and influence heat transfer performance problem.For this purpose, the double pipe heat exchanger of the present application includes outer tube, inner tube and variable flow module, the inner tube is arranged in the inside of outer tube, and the inside of inner tube is provided with a plurality of shunt pipe, shunt pipe is used for water flow, the space between outer tube and inner tube is used for passing through refrigerant. Variable flow module is set to at least one, and variable flow module is used to control the on-off of corresponding shunt pipe. In the case of adopting the above technical scheme, the use number of shunt pipe can be changed by variable flow module, and then the cross-sectional area of water side of double pipe heat exchanger is changed, so that the water flow of different flow can have a certain flow rate in double pipe heat exchanger, and then the heat transfer efficiency of double pipe heat exchanger and the energy efficiency of heat pump system are ensured.

Description

Technical Field

[0001] This invention relates to the field of heat exchanger technology, specifically providing a shell-and-tube heat exchanger and a heat pump system. Background Technology

[0002] A shell-and-tube heat exchanger is a simple and low-cost heat exchange device consisting of an inner tube and an outer tube forming a concentric shell. Two heat exchange media exchange heat by flowing in opposite or the same direction between the inner and outer tubes. In existing heat pump systems, shell-and-tube heat exchangers are commonly used to simultaneously provide hot water and heating. The inner tube is for water flow, while the space between the inner and outer tubes is for refrigerant flow. In heating mode, water from underfloor heating or radiators enters the inner tube for heating; in hot water mode, tap water enters the inner tube for heating.

[0003] However, the coaxial heat exchanger in a heat pump system is designed for heating conditions with "small temperature difference and large flow rate," resulting in higher system efficiency during heating. Since flow rate and temperature difference are inversely proportional for the same heat exchange capacity, and the temperature difference is relatively small during heating (e.g., 5-10℃ for underfloor heating supply and return water), the temperature difference increases when the heat pump system switches from heating to hot water production. For example, the inlet and outlet water temperature difference becomes 35-40℃. At this point, to provide the same heat exchange capacity, the water flow rate during hot water production drops sharply compared to the heating function. This leads to a sharp decrease in the water-side heat transfer coefficient of the coaxial heat exchanger, ultimately causing heat exchange deterioration and preventing the system from reaching the designed water temperature. Summary of the Invention

[0004] This application aims to solve at least one of the above-mentioned technical problems in the prior art, namely, to solve the problem that the heat exchange performance of the shell-and-tube heat exchanger in the existing heat pump system is affected when it is used to both provide heating and hot water.

[0005] In a first aspect, this application provides a shell-and-tube heat exchanger for a heat pump system, comprising:

[0006] outer tube;

[0007] An inner pipe is disposed inside the outer pipe, and multiple branch pipes are disposed inside the inner pipe. The branch pipes are used for water flow, and the space between the outer pipe and the inner pipe is used for refrigerant flow.

[0008] A flow converter module is provided, at least one of which is configured to control the opening and closing of the corresponding diversion pipe. The flow converter module includes a compression spring and a baffle plate. The baffle plate is disposed at the inlet end of the diversion pipe and is adapted to the inner cross-section of the inlet end of the diversion pipe. The diameter of the diversion pipe is larger than the diameter of the inlet end of the diversion pipe. One end of the compression spring is connected to the inner pipe and the other end is connected to the baffle plate. The flow converter module can open the diversion pipe under the action of water flow exceeding a threshold flow rate.

[0009] With the above technical solution, for heating operations, all branch pipes can be kept in a closed state to ensure a large flow of water. For hot water operations, only a few branch pipes, such as one, can be kept in a closed state to increase the flow velocity. In other words, the number of branch pipes used can be automatically adjusted by compressing springs and baffles, thereby changing the cross-sectional area of ​​the water side of the shell-and-tube heat exchanger. This ensures that water flows of different volumes can have a certain flow velocity in the shell-and-tube heat exchanger, thus guaranteeing the heat exchange efficiency of the shell-and-tube heat exchanger and the energy efficiency of the heat pump system.

[0010] In the preferred embodiment of the above-mentioned shell-and-tube heat exchanger, the shell-and-tube heat exchanger further includes a mounting plate, the mounting plate is provided with through holes, the number of through holes is equal to the number of the branch pipes, and the through holes are used for water to flow through;

[0011] The mounting plate is connected to the inner tube, and one end of the compression spring is connected to the mounting plate.

[0012] In the preferred embodiment of the above-mentioned shell-and-tube heat exchanger, when the inner tube is provided with three branch pipes, the mounting plate is also provided with mounting holes, which are located at the center of the mounting plate.

[0013] In the preferred embodiment of the above-mentioned shell-and-tube heat exchanger, the pre-compression force and maximum spring force of the compression spring are determined based on the following method:

[0014] Fit the pressure difference versus flow velocity curves for different numbers of the aforementioned splitter tubes;

[0015] Based on the relationship curves between the pressure difference and the flow velocity, the pre-compression force and the maximum spring force of the compression spring are determined.

[0016] In the preferred embodiment of the above-mentioned shell-and-tube heat exchanger, the compression spring is configured as a gradually increasing diameter spring, and the diameter of the gradually increasing diameter spring gradually increases in the direction away from the branch pipe.

[0017] When the above technical solution is adopted, setting the compression spring as a gradually decreasing diameter spring can reduce the required installation space while ensuring the supporting force of the compression spring, and improve the connection strength between the compression spring and the mounting plate.

[0018] In the preferred embodiment of the above-mentioned shell-and-tube heat exchanger, the flow converter module includes a control valve, which is located at the inlet end of the flow divider.

[0019] In the preferred embodiment of the above-mentioned shell-and-tube heat exchanger, the control valve is used to connect to the control module of the heat pump system, and the control module is configured as follows:

[0020] Based on the change in refrigerant-side load of the shell-and-tube heat exchanger, the corresponding number of control valves to be opened is determined.

[0021] In the preferred embodiment of the above-mentioned shell-and-tube heat exchanger, the number of the flow conversion modules is less than the number of the flow dividers, so that at least one of the flow dividers can only be in a closed state.

[0022] Using the above technical solution helps to reduce the setup cost of the converter module and simplify the structural setup.

[0023] In the preferred embodiment of the above-mentioned shell-and-tube heat exchanger, the diversion pipe without the flow converter module is located at the bottom of the inner tube.

[0024] Using the above technical solution helps to reduce the difficulty of water flow.

[0025] In the preferred embodiment of the above-mentioned shell-and-tube heat exchanger, the multiple branch pipes have the same diameter and are arranged symmetrically.

[0026] And / or the number of the shunt tubes is set to any value between 2 and 4.

[0027] In a second aspect, this application also provides a heat pump system comprising a shell-and-tube heat exchanger as described in any of the preceding claims.

[0028] With the above technical solution, for heating operations, all branch pipes can be kept in a closed state to ensure a large flow of water. For hot water operations, only a few branch pipes, such as one, can be kept in a closed state to increase the flow velocity. In other words, the cross-sectional area of ​​the water side of the shell-and-tube heat exchanger can be changed by altering the number of branch pipes used. This allows water flows of different volumes to have a certain velocity within the shell-and-tube heat exchanger, thereby ensuring the heat exchange efficiency of the shell-and-tube heat exchanger and the energy efficiency of the heat pump system. Attached Figure Description

[0029] The shell-and-tube heat exchanger of this application will now be described with reference to the accompanying drawings. In the drawings:

[0030] Figure 1 This is an overall structural diagram of the shell-and-tube heat exchanger of this application;

[0031] Figure 2 This is a schematic diagram of the inner tube according to one embodiment of this application;

[0032] Figure 3 This is a cross-sectional view of the middle portion of the inner tube according to an embodiment of this application;

[0033] Figure 4 This is a rear view of the middle portion of the inner tube according to an embodiment of this application;

[0034] Figure 5 This is a schematic diagram showing the interaction between the converter module and the inner tube in this application;

[0035] Figure 6 This is a schematic diagram showing the front view of the converter module in this application;

[0036] Figure 7 This is a schematic diagram showing the rear view of the converter module in this application;

[0037] Figure 8 This is a schematic diagram showing the side view of the converter module of this application;

[0038] Figure 9 This is a schematic diagram of the inner tube according to another embodiment of this application;

[0039] Figure 10 This is a schematic diagram of the inner tube according to yet another embodiment of this application;

[0040] Figure 11 This is a schematic diagram of a heat pump system according to an embodiment of this application.

[0041] List of reference numerals

[0042] 2. Shell-and-tube heat exchanger; 21. Outer tube; 22. Inner tube; 23. Diverter tube; 24. Compression spring; 25. Baffle; 26. Mounting plate; 3. Compressor; 4. Four-way reversing valve; a. First port; b. Second port; c. Third port; d. Fourth port; 5. Evaporator; 6. Throttling element; 7. Regenerator. Detailed Implementation

[0043] Preferred embodiments of this application are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of this application and are not intended to limit the scope of protection of this application. For example, although two of the three diverter pipes in the drawings are located at the top of the inner tube and the other at the bottom, this positional relationship is not fixed. Those skilled in the art can adjust it as needed to adapt to specific applications, such as placing two diverter pipes at the bottom of the inner tube and the other at the top. Similarly, although the converter module is described in this embodiment in conjunction with a compression spring and a baffle, this is not intended to limit the scope of protection of this application. Those skilled in the art can modify it as needed without departing from the principles of this application, for example, by setting the converter module as a control valve.

[0044] It should be noted that in the description of this application, the terms "center," "upper," "lower," "left," "right," "inner," and "outer," which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. These are used merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, in the description of this application, "a plurality of" refers to at least two.

[0045] Furthermore, it should be noted that, in the description of this application, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0046] As described in the background section, a shell-and-tube heat exchanger is a simple and low-cost heat exchange device. It consists of an inner tube and an outer tube forming a concentric shell, through which two heat exchange media exchange heat by flowing in opposite or the same direction between the inner and outer tubes. In existing heat pump systems, shell-and-tube heat exchangers are typically used to simultaneously achieve both hot water production and heating functions. The inner tube is used for water flow, while the space between the outer and inner tubes is used for refrigerant flow. In the heating function, water from underfloor heating or radiators enters the inner tube for heating, and in the hot water function, tap water enters the inner tube for heating.

[0047] However, the coaxial heat exchanger in a heat pump system is designed for heating conditions with "small temperature difference and large flow rate," resulting in higher system efficiency during heating. Since flow rate and temperature difference are inversely proportional for the same heat exchange capacity, and the temperature difference is relatively small during heating (e.g., 5-10℃ for underfloor heating supply and return water), the temperature difference increases when the heat pump system switches from heating to hot water production. For example, the inlet and outlet water temperature difference becomes 35-40℃. At this point, to provide the same heat exchange capacity, the water flow rate during hot water production drops sharply compared to the heating function. This leads to a sharp decrease in the water-side heat transfer coefficient of the coaxial heat exchanger, ultimately causing heat exchange deterioration and preventing the system from reaching the designed water temperature.

[0048] To address the issue of heat exchange performance limitations in existing coaxial heat exchangers used for both heating and hot water production in heat pump systems, this application provides a coaxial heat exchanger for use in a heat pump system. The coaxial heat exchanger includes an outer tube, an inner tube, and a flow converter module. The inner tube is located inside the outer tube and contains multiple branch pipes for water flow. The space between the outer and inner tubes is used for refrigerant flow. At least one flow converter module is provided, and it controls the opening and closing of the corresponding branch pipe. The flow converter module includes a compression spring and a baffle. The baffle is located at the inlet end of the branch pipe and its cross-section is adapted to the inlet end of the branch pipe. The diameter of the branch pipe is larger than the diameter of its inlet end. One end of the compression spring is connected to the inner tube, and the other end is connected to the baffle. The flow converter module can open the branch pipe under the action of water flow exceeding a threshold flow rate.

[0049] With the above technical solution, for heating operations, all branch pipes can be kept in a closed state to ensure a large flow of water. For hot water operations, only a few branch pipes, such as one, can be kept in a closed state to increase the flow velocity. In other words, the number of branch pipes used can be automatically adjusted by compressing springs and baffles, thereby changing the cross-sectional area of ​​the water side of the shell-and-tube heat exchanger. This ensures that water flows of different volumes can have a certain flow velocity in the shell-and-tube heat exchanger, thus guaranteeing the heat exchange efficiency of the shell-and-tube heat exchanger and the energy efficiency of the heat pump system.

[0050] The following reference Figures 1 to 10 The shell-and-tube heat exchanger of this application is described below. Figure 1 This is an overall structural diagram of the shell-and-tube heat exchanger of this application; Figure 2 This is a schematic diagram of the inner tube according to one embodiment of this application; Figure 3 This is a cross-sectional view of the middle portion of the inner tube according to an embodiment of this application; Figure 4 This is a rear view of the middle portion of the inner tube according to an embodiment of this application; Figure 5 This is a schematic diagram showing the interaction between the converter module and the inner tube in this application; Figure 6 This is a schematic diagram showing the front view of the converter module in this application; Figure 7This is a schematic diagram showing the rear view of the converter module in this application; Figure 8 This is a schematic diagram showing the side view of the converter module of this application. Figure 9 This is a schematic diagram of the inner tube according to another embodiment of this application; Figure 10 This is a schematic diagram of the inner tube according to another embodiment of this application.

[0051] like Figures 1 to 8 As shown, in a preferred embodiment, the coaxial heat exchanger 2 for a heat pump system includes an outer tube 21, an inner tube 22, and a flow converter module. The inner tube 22 is disposed inside the outer tube 21, and multiple branch pipes 23 are disposed inside the inner tube 22. The branch pipes 23 are used for water flow, and the space between the outer tube 21 and the inner tube 22 is used for refrigerant flow. The multiple branch pipes 23 have equal diameters and are symmetrically arranged. At least one flow converter module is provided, which controls the on / off state of the corresponding branch pipe 23. The number of flow converter modules is less than the number of branch pipes 23, so that at least one branch pipe 23 can only be in a continuous flow state. The branch pipe 23 without a flow converter module is located at the bottom of the inner tube 22.

[0052] In this embodiment, the inner tube 22 is provided with three branch pipes 23, see reference. Figure 4 The diameter of the diverter pipe 23 is larger than the diameter of its inlet end. (See reference...) Figures 5 to 8 Two converter modules are configured, each including a compression spring 24 and a baffle 25. The compression spring 24 is a tapered-diameter spring, with its diameter gradually increasing away from the diverter pipe 23. The baffle 25 is located at the inlet end of the diverter pipe 23, and its inner cross-section is adapted to the inlet end of the diverter pipe 23. An mounting plate 26 is installed inside the inner pipe 22 and is connected to the inner pipe 22. The mounting plate 26 has through holes and mounting holes. The number of through holes is equal to the number of diverter pipes 23. The through holes are used for water flow, and the mounting holes are located in the center of the mounting plate 26, facilitating technicians to hold the mounting plate 26 and insert it into the inner pipe 22. One end of the compression spring 24 is connected to the mounting plate 26, and the other end is connected to the baffle 25. The converter module can open the corresponding diverter pipe 23 under the action of water flow exceeding the threshold flow rate.

[0053] It needs to be explained that when the shell-and-tube heat exchanger 2 is running, as the water flows to the inlet of each branch pipe 23, for branch pipes 23 without a flow converter at the inlet, the water flows directly through the branch pipe 23. For branch pipes 23 with a flow converter at the inlet, if the water flow is large, the baffle 25 is impacted by the water flow and the compression spring 24 is stretched. At this time, the baffle 25 enters the branch pipe 23. Since the diameter of the branch pipe 23 is larger than the diameter of the inlet of the branch pipe 23, the baffle 25 can no longer block the branch pipe 23, allowing the corresponding branch pipe 23 to enter the pass state. In other words, for different operating conditions, the water side area of ​​the shell-and-tube heat exchanger 2 can be spontaneously adjusted by the compression spring 24 and the baffle 25, so that water of different flow rates can have a certain flow velocity in the shell-and-tube heat exchanger 2, thereby ensuring the heat exchange efficiency of the shell-and-tube heat exchanger 2 and the energy efficiency of the heat pump system.

[0054] Furthermore, regarding the specific configuration of the compression spring 24, those skilled in the art can first fit the relationship curves between the inlet and outlet pressure difference and the flow velocity for different numbers of diverter pipes 23. For example, continuing with... Figure 5 Taking this as an example, the relationship curves between the inlet and outlet pressure difference and the flow velocity of three diversion pipes 23 and one diversion pipe 23 are fitted respectively. Then, the pre-compression force and maximum spring force of the compression spring 24 are determined by the two inlet and outlet pressure differences corresponding to the threshold flow rate at the same flow rate, i.e., the effective area of ​​the baffle 25. Then, the length of the compression spring 24 is determined according to the material, shape and other factors of the selected compression spring 24. The pre-compression force and maximum spring force of the compression spring 24 are respectively to ensure that the baffle 25 can block the inlet end of the diversion pipe 23 when the flow rate is small, and that the baffle 25 enters the diversion pipe 23 under the action of water flow when the flow rate is large, so that the diversion pipe 23 is in a passable state.

[0055] Furthermore, in this embodiment, although the water-side area of ​​the shell-and-tube heat exchanger 2 can be automatically adjusted according to the flow rate when the converter module is configured as a compression spring 24 and a baffle 25, its configuration is not fixed and can be modified according to the needs of those skilled in the art, as long as the on / off state of the corresponding diversion pipe 23 can be controlled by the converter module.

[0056] In some implementations, the converter module can be configured as a control valve, which is located at the inlet end of the shunt pipe 23. In this case, the control valve can also control the on / off state of the corresponding shunt pipe 23.

[0057] Furthermore, the control valves are used to connect to the control module of the heat pump system. The control module is configured to determine the number of control valves to open based on the refrigerant-side load change of the shell-and-tube heat exchanger 2.

[0058] In this embodiment, the control valve can be a solenoid valve, and there can be two control valves. In heating mode, the water side of the shell-and-tube heat exchanger 2 is circulating hot water with a small inlet-outlet temperature difference. At this time, the refrigerant load is relatively stable and low, and the water flow rate is large. In hot water mode, to heat tap water once, the refrigerant load will rise sharply to provide more heat, and the water flow rate will be small. That is, if the refrigerant load changes sharply, it indicates that the system has switched to hot water mode. In this case, all control valves can be closed to keep only one branch pipe 23 open. If the refrigerant load changes sharply, it indicates that the system has switched to heating mode. In this case, all control valves can be opened to keep all branch pipes 23 open, thereby ensuring the heat exchange efficiency of the shell-and-tube heat exchanger 2 and the energy efficiency of the heat pump system under different operating conditions.

[0059] Of course, the way the control valves are opened and closed is not fixed. In an alternative implementation, the opening and closing of each control valve can be controlled solely based on the current function of the heat pump system. For example, if the current function is hot water production, all control valves can be closed; if the current function is heating, all control valves can be opened. However, considering that if hot water can be stored in a water tank, and the water in the tank is kept warm by circulating through the shell-and-tube heat exchanger 2, the temperature difference between the inlet and outlet water on the water side of the shell-and-tube heat exchanger 2 may be small. If all control valves are closed in this case, it would be detrimental to heat preservation. Therefore, determining the opening of the corresponding control valve based solely on the change in the refrigerant load on the shell-and-tube heat exchanger 2 is a better choice.

[0060] It should also be explained that, in this embodiment, setting the compression spring 24 as a tapered diameter spring reduces the required installation space while ensuring the supporting force of the compression spring 24 and improves the connection strength between the compression spring 24 and the mounting plate 26. However, its setting is not fixed. In an alternative embodiment, the compression spring 24 can be set as a constant diameter spring. However, considering the connection strength between the compression spring 24 and the mounting plate 26, setting the compression spring 24 as a tapered diameter spring is a better choice. In addition, although the compression spring 24 is connected through the mounting plate 26 in this embodiment, its setting is not fixed. Those skilled in the art can change the installation method of the compression spring 24 according to requirements, as long as it does not affect the normal functioning of each shunt pipe 23 and the converter module.

[0061] Those skilled in the art will understand that, in this embodiment, setting the number of converter modules to be less than the number of shunt pipes 23, so that at least one shunt pipe 23 can only be in a closed state, can reduce the installation cost of converter modules and simplify the structural setup. However, the number of converter modules relative to the number of shunt pipes 23 is not fixed, and those skilled in the art can change it according to their needs, as long as it does not hinder the normal functioning of this application. In an alternative embodiment, the number of converter modules can be set to be equal to the number of shunt pipes 23. In another alternative embodiment, taking the inner pipe 22 with three shunt pipes 23 as an example, only one converter module can be set, that is, in this case, two shunt pipes 23 can only be in a closed state. However, considering the premise of increasing the flow rate at low flow rates, making only one shunt pipe 23 in a closed state is a better choice.

[0062] Furthermore, in this embodiment, setting three diversion pipes 23 can increase the flow velocity of the water at low flow rates while avoiding significant resistance to the water flow when passing through the diversion pipes 23 at high flow rates, thereby ensuring the heat exchange efficiency of the shell-and-tube heat exchanger 2 in different modes. However, its arrangement is not fixed, and those skilled in the art can change the number of diversion pipes 23 according to requirements. In an alternative embodiment, see [reference needed]. Figure 9 Two shunt pipes 23 can be configured, in which case one converter module is installed at the inlet end of either shunt pipe 23. In another alternative embodiment, see [reference needed]. Figure 10 The shunt tubes 23 can be set to four. In this case, three converter modules are set at the inlet end of the two upper shunt tubes 23 and any one of the lower shunt tubes 23.

[0063] It should be explained that in this embodiment, selecting a bottom branch pipe 23 without a flow converter module can reduce the difficulty of water flow, but its configuration is not fixed. In an alternative embodiment, any branch pipe 23 can be selected without a flow converter module.

[0064] Furthermore, in this embodiment, the multiple branch pipes 23 have the same diameter and are symmetrically arranged. However, this arrangement is not mandatory; those skilled in the art can change the diameter and position of each branch pipe 23 as needed. In an alternative embodiment, see [reference needed]. Figure 9 Alternatively, the two horizontally positioned branch pipes 23 can be changed to a vertically positioned branch pipe. In this case, the diameter of the branch pipe 23 at the bottom can be smaller than the diameter of the branch pipe 23 at the top. For another alternative embodiment, see [reference needed]. Figure 4 In the case of setting a diversion pipe 23, two diversion pipes 23 can also be set at the bottom of the inner pipe 22 and one diversion pipe 23 can be set at the top.

[0065] In a second aspect, this application also provides a heat pump system, which includes any of the aforementioned coaxial heat exchangers.

[0066] With the above technical solution, for heating operations, all branch pipes can be kept in a closed state to ensure a large flow of water. For hot water operations, only a few branch pipes, such as one, can be kept in a closed state to increase the flow velocity. In other words, the cross-sectional area of ​​the water side of the shell-and-tube heat exchanger can be changed by altering the number of branch pipes used. This allows water flows of different volumes to have a certain velocity within the shell-and-tube heat exchanger, thereby ensuring the heat exchange efficiency of the shell-and-tube heat exchanger and the energy efficiency of the heat pump system.

[0067] See below. Figure 11 The heat pump system of this application will now be described. Figure 11 This is a schematic diagram of a heat pump system according to an embodiment of this application.

[0068] like Figure 11 As shown, the heat pump system includes a shell-and-tube heat exchanger 2, a compressor 3, a four-way reversing valve 4, an evaporator 5, a throttling element 6, and a regenerator 7. The exhaust port of the compressor 3 is connected to the first port a of the four-way reversing valve 4, the second port b of the four-way reversing valve 4 is connected to the first port on the refrigerant side of the shell-and-tube heat exchanger 2, the second port on the refrigerant side of the shell-and-tube heat exchanger 2 is connected to the first port (upper left port in the diagram), the second port (lower left port in the diagram) of the regenerator 7 is connected to the first port (left side port in the diagram) of the throttling element 6, the third port (upper right port in the diagram) of the regenerator 7 is connected to the suction port of the compressor 3, and the fourth port (lower right port in the diagram) of the regenerator 7 is connected to the third port c of the four-way reversing valve 4. A first heat exchange flow path is formed between the first port and the second port of the regenerator 7, and a second heat exchange flow path is formed between the third port and the fourth port of the regenerator 7. The second port (right port in the direction shown in the figure) of the throttling element 6 is connected to the first port (left port in the direction shown in the figure) of the evaporator 5, and the second port (right port in the direction shown in the figure) of the evaporator 5 is connected to the fourth port d of the four-way reversing valve 4.

[0069] In heating or hot water supply mode, compressor 3 discharges high-temperature and high-pressure refrigerant gas, which enters the refrigerant side of shell-and-tube heat exchanger 2 through the first port a and the second port b of four-way reversing valve 4 to heat the water flow on the water side. After heat exchange, the refrigerant gas is subcooled through the first port and the second port of regenerator 7, and then throttled and depressurized by throttling element 6 to become low-temperature and low-pressure refrigerant liquid. The refrigerant liquid enters evaporator 5 to absorb heat and becomes low-temperature and low-pressure refrigerant gas. Then, the low-temperature and low-pressure refrigerant gas enters regenerator 7 through the third port c and the fourth port d of four-way reversing valve 4 for superheating, and finally returns to compressor 3 to enter the next cycle.

[0070] It should be noted that the water-side configuration of the shell-and-tube heat exchanger 2 is described in the aforementioned embodiments and will not be repeated here. Furthermore, this application only provides one configuration of the inner tube 22 of the shell-and-tube heat exchanger 2; those skilled in the art can apply it to shell-and-tube heat exchangers 2 with different appearances as needed. In addition, this embodiment only provides a specific configuration of the refrigerant circulation loop of a heat pump system; those skilled in the art can modify it as needed, for example, omitting the regenerator 7 and the four-way reversing valve 4.

[0071] Those skilled in the art will understand that although some embodiments described herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, any of the claimed embodiments in the claims of this application can be used in any combination.

[0072] The technical solutions of this application have been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of this application.

Claims

1. A shell-and-tube heat exchanger (2) for use in a heat pump system, characterized in that, include: Outer tube (21); An inner pipe (22) is disposed inside the outer pipe (21), and a plurality of branch pipes (23) are disposed inside the inner pipe (22). The branch pipes (23) are used to supply water flow, and the space between the outer pipe (21) and the inner pipe (22) is used to supply refrigerant flow. A flow converter module is provided, wherein at least one flow converter module is provided, and the flow converter module is used to control the opening and closing of the corresponding diversion pipe (23). The flow converter module includes a compression spring (24) and a baffle (25). The baffle (25) is provided at the inlet end of the diversion pipe (23), and the baffle (25) is adapted to the inner cross section of the inlet end of the diversion pipe (23). The pipe diameter of the diversion pipe (23) is larger than the diameter of the inlet end of the diversion pipe (23). One end of the compression spring (24) is connected to the inner pipe (22), and the other end is connected to the baffle (25). The flow converter module can open the diversion pipe (23) under the action of water flow greater than the threshold flow rate.

2. The shell-and-tube heat exchanger (2) according to claim 1, characterized in that, The shell-and-tube heat exchanger (2) also includes a mounting plate (26), which is provided with through holes. The number of through holes is equal to the number of the branch pipes (23). The through holes are used for water to flow through. The mounting plate (26) is connected to the inner tube (22), and one end of the compression spring (24) is connected to the mounting plate (26).

3. The shell-and-tube heat exchanger (2) according to claim 2, characterized in that, When the inner tube (22) is provided with three of the branch pipes (23), the mounting plate (26) is also provided with mounting holes, which are located at the center of the mounting plate (26).

4. The shell-and-tube heat exchanger (2) according to claim 1, characterized in that, The pre-compression force and maximum spring force of the compression spring (24) are determined based on the following: Fit the pressure difference versus flow velocity curves of different numbers of the splitter tubes (23); Based on the relationship curves between the pressure difference and the flow velocity, the pre-compression force and the maximum spring force of the compression spring (24) are determined.

5. The shell-and-tube heat exchanger (2) according to claim 1 or 2, characterized in that, The compression spring (24) is configured as a tapered diameter spring, and the diameter of the tapered diameter spring gradually increases in the direction away from the diverter (23).

6. The shell-and-tube heat exchanger (2) according to claim 1, characterized in that, The number of the converter modules is less than the number of the shunt tubes (23) so that at least one of the shunt tubes (23) can only be in the pass state.

7. The shell-and-tube heat exchanger (2) according to claim 6, characterized in that, The shunt pipe (23) without the converter module is located at the bottom of the inner pipe (22).

8. The shell-and-tube heat exchanger (2) according to claim 1, characterized in that, The multiple branch pipes (23) have the same diameter and are arranged symmetrically.

9. The shell-and-tube heat exchanger (2) according to claim 1, characterized in that, The number of the shunt tubes (23) is set to any value between 2 and 4.

10. A heat pump system, characterized in that, The heat pump system includes a shell-and-tube heat exchanger (2) as described in any one of claims 1-9.

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