Variable shunt structure suitable for heat exchanger and heat pump water chilling unit

Abstract

The invention relates to a variable shunt structure suitable for a heat exchanger and a heat pump water chilling unit. In the structure, a plurality of heat exchange passages configured for a heat exchanger body are connected with a first branch and a second branch correspondingly; the plurality of first branches are connected in parallel to form a first parallel end, and are provided with a first control valve and a second control valve; and the plurality of second branches are connected in parallel to form a second parallel end. Through combination of variable shunt design and multi-control valve cooperative control, flexible switching of the number of heat exchanger shunts in different modes can be achieved, the defects that traditional unit shunts cannot be changed, and the difference requirement of dual-mode shunts cannot be met are overcome, it is ensured that the heat exchanger can efficiently exchange heat in the dual modes, the core load of the unit is reduced, and the energy consumption of the unit is reduced. The overall energy efficiency of the unit is improved, and energy consumption is reduced.

Description

Technical Field

[0001] This application relates to the field of heat exchange equipment technology, specifically to a variable branch structure applicable to heat exchangers and a heat pump chiller unit. Background Technology

[0002] For heat pump chillers, the flow paths of the heat exchanger inside the unit are generally kept consistent in both heating and cooling modes. In cooling mode, the heat exchanger acts as a condenser, where the pressure drop is smaller and the flow path requirements are less, but the refrigerant needs to remain flowing within the heat exchanger for a longer period of time to improve the heat exchange efficiency of the finned heat exchanger. In heating mode, the heat exchanger acts as an evaporator, where the flow path requirements are greater, and the refrigerant needs to distribute heat as evenly as possible within the heat exchanger to improve its heat exchange efficiency.

[0003] However, most heat exchangers used in traditional units have fixed flow path distribution in heating or cooling modes. This makes them incompatible with the different flow path distribution requirements during evaporation and condensation, preventing them from achieving optimal heat exchange performance. Therefore, to address the problem of traditional units' flow path design being unable to adapt to dual-mode requirements and resulting in low overall heat exchange efficiency, there is an urgent need to design a heat exchanger that can accommodate the different flow path distribution requirements in both heating and cooling modes. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, this application provides a variable branching structure suitable for heat exchangers and a heat pump chiller unit, specifically adopting the following technical solution: A variable branch structure applicable to a heat exchanger is used to deliver refrigerant to the heat exchanger in heating or cooling mode. The structure includes a heat exchanger body, a branch element, a first control valve, a second control valve, a first branch, and a second branch. The heat exchanger body is equipped with multiple heat exchange passages, one end of each heat exchange passage is connected to the first branch, and the other end of each heat exchange passage is connected to the second branch. Multiple first branches are connected in parallel to form a first parallel end, which includes a first parallel unit and a second parallel unit. The first control valve is located between the first parallel unit and the second parallel unit, and the second control valve is arranged in the second parallel unit. Multiple second branches are connected in parallel to form a second parallel terminal. This second parallel terminal is connected to one end of the flow divider. The other end of the flow divider is equipped with a first one-way valve, which controls the refrigerant to flow unidirectionally into the other end of the flow divider.

[0005] Optional: A third branch is provided between the second control valve and the first check valve. A second check valve is configured on the third branch, and the refrigerant flow in the third branch is controlled by the second check valve to be directed only toward the first check valve.

[0006] Optional: Both the first and second control valves are solenoid valves.

[0007] Furthermore: When the heat exchanger is in heating mode, both the first control valve and the second control valve are in the open state.

[0008] Furthermore: when the heat exchanger is in cooling mode, the first control valve is in the on state and the second control valve is in the off state; or the first control valve is in the off state and the second control valve is in the on state.

[0009] Optionally: A fourth branch is connected in parallel to the side of the second control valve. One end of the fourth branch is connected to the second parallel unit located between the first control valve and the second control valve, and the other end of the fourth branch is connected to the third branch located between the second control valve and the second check valve. A third control valve is provided on the fourth branch, and the refrigerant flow direction in the fourth branch is controlled by the third control valve to be towards the second check valve.

[0010] Optional: The first and third control valves are solenoid valves, the second control valve is a check valve, and the refrigerant flow direction of the second control valve is towards the first control valve.

[0011] Optional: When the heat exchanger is in heating mode, the first control valve is in the open state and the third control valve is in the closed state.

[0012] Optionally: When the heat exchanger is in cooling mode, the first control valve is in the open state and the third control valve is in the closed state; or the first control valve is in the closed state and the third control valve is in the open state.

[0013] In addition, this application also discloses a heat pump chiller unit, including a compressor, a four-way reversing valve, a first heat exchanger, a throttle valve and a second heat exchanger connected in sequence to form a refrigerant circuit, wherein the second heat exchanger adopts the variable branch structure as described above.

[0014] The technical solution of this application achieves the following beneficial effects: The variable branching structure of this application combines variable branching design with multi-control valve coordinated control to achieve flexible switching of the number of heat exchanger branches in different modes. In heating mode, all heat exchange passages of the heat exchanger body are connected in parallel with the first and second branches to form a multi-branching structure, which meets the requirement of uniform refrigerant distribution when the heat exchanger is used as an evaporator. In cooling mode, different control valves are turned off or on to reduce the number of branches and increase the refrigerant flow time in the heat exchanger, so as to adapt to the low-pressure-drop heat exchange requirement when the heat exchanger is used as a condenser. This solves the defect of traditional unit branching that cannot be changed and cannot take into account the different requirements of branching in two modes, ensuring that the heat exchanger can efficiently exchange heat in both modes, reducing the core load of the unit, and achieving overall unit energy efficiency improvement and energy consumption reduction. Attached Figure Description

[0015] Figure 1This is a schematic diagram of the variable branching structure in Embodiment 1 of this application.

[0016] Figure 2 This is a schematic diagram of the variable branching structure in Embodiment 2 of this application.

[0017] Figure 3 This is a schematic diagram of refrigerant flow in the heating mode of the heat pump chiller unit in Embodiment 3 of this application.

[0018] Figure 4 This is a schematic diagram of refrigerant flow in the heat pump chiller unit of Embodiment 3 of this application, when the variable frequency compressor is running at low frequency.

[0019] Figure 5 This is a schematic diagram of refrigerant flow in the heat pump chiller unit of Embodiment 3 of this application, when the cooling mode is achieved by using a fixed-frequency compressor or a variable-frequency compressor operating at high frequency.

[0020] Figure 6 This is a schematic diagram of refrigerant flow in the heating mode of the heat pump chiller unit in Embodiment 4 of this application.

[0021] Figure 7 This is a schematic diagram of refrigerant flow in the heat pump chiller unit of Embodiment 4 of this application, when the variable frequency compressor is running at low frequency.

[0022] Figure 8 This is a schematic diagram of refrigerant flow in the heat pump chiller unit of Embodiment 4 of this application, when the cooling mode is achieved by using a fixed-frequency compressor or a variable-frequency compressor operating at high frequency. Detailed Implementation

[0023] The present application will now be further described with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application and should not be construed as limiting the scope of protection of the present application. It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present application.

[0024] Example 1: This embodiment 1 specifically discloses a variable branching structure applicable to heat exchangers, which is suitable for heat pump chillers to deliver refrigerant into the heat exchanger in heating or cooling mode. Specifically, as shown in the example... Figure 1 As shown, the variable branch structure includes a heat exchanger body 6, a branch element 5, a first control valve 11, a second control valve 10, a first branch 8, and a second branch 7.

[0025] In detail, the heat exchanger body 6 is equipped with multiple heat exchange passages, one end of each heat exchange passage is connected to a first branch 8, and the other end of each heat exchange passage is connected to a second branch 7. Taking the heat exchanger of this embodiment 1 as an example, combined with... Figure 1As shown, the heat exchanger body 6 preferably has 6 heat exchange passages. Correspondingly, in this embodiment 1, there are 6 first branches 8 (i.e., branches 8.1 to 8.6) and 6 second branches 7 (i.e., branches 7.1 to 7.6). The left port of each heat exchange passage is connected to one first branch 8, and the right port of each heat exchange passage is connected to one second branch 7.

[0026] Six of the first branch lines 8 are connected in parallel to form the first parallel terminal 801, meaning that all the first branch lines 8 are connected in parallel to the same main conduit. In this embodiment 1, the first parallel terminal 801 is divided into a first parallel unit and a second parallel unit, combined with... Figure 1 As shown, the parallel ends of branches 8.1, 8.2, and 8.3 together form the first parallel unit, while the parallel ends of branches 8.4, 8.5, and 8.6 together form the second parallel unit. The first control valve 11 is located between the first and second parallel units, specifically between branches 8.3 and 8.4. The second control valve 10 is arranged within the second parallel unit; that is, it is positioned near the lower end of the main pipe. Figure 1 As shown, in this embodiment 1, the second control valve 10 is located between branch 8.5 and branch 8.6.

[0027] In this embodiment 1, the number of first branches 7 is set to be equal to the number of second branches 8. In one embodiment, the number of first branches 7 is even, and the number of first branches 7 in the first parallel unit is equal to the number of first branches 7 in the second parallel unit. In another embodiment, the number of first branches 7 is odd, and the difference between the number of first branches 7 in the first parallel unit and the number of first branches 7 in the second parallel unit is one or two; for example, the number of first branches 7 in the first parallel unit is one more than the number of first branches 7 in the second parallel unit. The second control valve 10 can specifically be located between two adjacent first branches 7 near the bottom of the heat exchanger.

[0028] Furthermore, the six second branches 7 are connected in parallel to form a second parallel end 701, wherein the second parallel end 701 is connected to one end of the diverter 5, and the other end of the diverter 5 is provided with a first one-way valve 9, through which the refrigerant can be controlled to flow into the other end of the diverter 5 in one direction.

[0029] Furthermore, a third branch 13 is provided between the second control valve 10 and the first check valve 9. A second check valve 12 is configured on the third branch 13. The flow direction of the refrigerant in the third branch 13 can be controlled by the second check valve 12 to be directed only toward the first check valve 9.

[0030] As a preferred embodiment, in this embodiment 1, the first control valve 11 is preferably a solenoid valve, and the second control valve 10 is also preferably a solenoid valve. Furthermore, in this embodiment 1, the first check valve 9 and the second check valve 12 are preferably check valves.

[0031] Based on the variable branching structure of Embodiment 1, when the refrigerant circuit of the heat pump chiller is in heating mode, the heat exchanger body 6 acts as an evaporator. The refrigerant within the heat exchanger body 6 absorbs heat uniformly in each heat exchange path. At this time, both the first control valve 11 and the second control valve 10 can be controlled to be in the conducting state. When the refrigerant in the refrigerant circuit flows, the refrigerant flows into the branching component 5 through the first one-way valve 9, and then is evenly distributed into the six second branches 7 through the branching component 5. The refrigerant enters the six heat exchange paths of the heat exchanger body 6 through the second branches 7, and after sufficient heat exchange in the heat exchange paths, it flows to the six first branches 8 respectively. Since both the first control valve 11 and the second control valve 10 are conducting, the six first branches 8 converge at the first parallel end 801 and flow into the refrigerant circuit for circulation. In this stage, since the heat exchanger body is evenly divided into six heat exchange paths, the refrigerant entering the heat exchanger body 6 is evenly divided into six paths for uniform heat absorption, improving its heat exchange efficiency.

[0032] When the refrigerant circuit of the heat pump chiller is in cooling mode, the variable frequency compressor of the heat pump chiller operates at high and low frequencies, resulting in different refrigerant states: in low-frequency operation, the amount of refrigerant circulating is less and the flow rate is low; in high-frequency operation, the amount of refrigerant circulating is more and the flow rate is high.

[0033] For low-frequency operation, the first control valve 11 can be controlled to be in the open state, while the second control valve 10 is in the closed state. When the refrigerant flows in the refrigerant circuit in cooling mode, since the refrigerant can pass through the first control valve 11 but cannot pass through the second control valve 10, the refrigerant will be evenly distributed by the five first branches 8 (i.e., branches 8.1~8.5), and then flow into the heat exchange passage of the heat exchanger body 6. It is then guided to the flow divider 5 through the five second branches 7 (i.e., branches 7.1~7.5). Due to the obstruction of the first one-way valve 9, the refrigerant in the flow divider 5 cannot flow directly to the refrigerant circuit. Therefore, the refrigerant in the flow divider 5 flows back into the heat exchange passage of the heat exchanger body through the last second branch 7 (i.e., branch 7.6), and then flows to the third branch 13 through the last first branch 8 (i.e., branch 8.6), and finally merges into the refrigerant circuit through the third branch 13. In a variable-frequency compressor operating at low frequencies, the refrigerant circulation volume is small and the flow rate is slow. Therefore, it's necessary to avoid excessive branching, which could lead to low flow rates or short flow paths in individual branches, resulting in insufficient heat exchange. The variable-frequency structure forms a flow structure with 5 branching paths and 1 confluence path, reducing the number of branching paths while increasing the flow length of each individual branch. This balances flow rate and subcooling, preventing heat waste at low flow rates. It ensures sufficient refrigerant flow rate within the heat exchange path and further reduces temperature, achieving higher subcooling and fully utilizing the heat exchanger's area to improve refrigeration efficiency.

[0034] For high-frequency operation, the first control valve 11 can be controlled to be closed and the second control valve 10 to be open. When the refrigerant in the refrigerant circuit flows in the cooling mode, since the refrigerant can pass through the second control valve 10 but cannot pass through the first control valve 11, the refrigerant is evenly distributed by the three first branches 8 (i.e., branches 8.1~8.3) and then flows into the heat exchange passage of the heat exchanger body 6. It is then conducted to the flow divider 5 through the three second branches 7 (i.e., branches 7.1~7.3). Due to the obstruction of the first one-way valve 9, the refrigerant in the flow divider 5 cannot flow directly to the refrigerant circuit. Therefore, the refrigerant in the flow divider 5 is evenly distributed to the three second branches 7 (i.e., branches 7.4~7.6) and flows back into the heat exchange passage of the heat exchanger body. It then flows to the third branch 13 through the three first branches 8 (i.e., branches 8.4~8.6) and merges into the refrigerant circuit through the third branch 13. Under high-frequency operation, the total refrigerant volume is large and the flow rate is fast. If a 6-branch design is still used, the short flow path of each branch will result in a short residence time of the refrigerant in the heat exchanger body, leading to insufficient condensation, instability of the refrigerant state, and decreased cooling efficiency. Therefore, by combining the three heat exchange passages at the top and the three at the bottom to form three branch paths, the flow length of each branch path is significantly increased, making the refrigerant flow path in the heat exchanger body longer. This extends the heat exchange time, ensuring sufficient condensation of the refrigerant under high flow rates and maximizing cooling efficiency.

[0035] It should be noted that when the refrigerant circuit of the heat pump chiller is in cooling mode, the heat pump chiller can also use a fixed-frequency compressor to control the refrigerant flow. Its state is the same as that of the variable-frequency compressor in high-frequency operation. The amount of refrigerant circulating is larger and the flow rate is higher. At this time, the corresponding control process and refrigerant flow process are basically the same as those of the variable-frequency compressor in high-frequency operation.

[0036] Example 2: This embodiment 2 also discloses a variable branching structure applicable to heat exchangers, which is suitable for heat pump chillers to deliver refrigerant into the heat exchanger in heating or cooling mode. Specifically, as shown in the example... Figure 2 As shown, the variable branching structure of this embodiment 2 is the same as the basic structure of embodiment 1. The difference is that in this embodiment 2, the first control valve 11 is preferably a solenoid valve, while the second control valve 10 is preferably a check valve, and the refrigerant flow direction of the second control valve 10 is towards the first control valve 11. In addition, in this embodiment 2, the first check valve 9 and the second check valve 12 are also preferably check valves.

[0037] Furthermore, in combination Figure 2 As shown, in this embodiment 2, a fourth branch 14 is configured in parallel to the side of the second control valve 10. One end of the fourth branch 14 is connected to the second parallel unit 801 located between the first control valve 11 and the second control valve 10, that is, the parallel end between branch 8.5 and branch 8.6. The other end of the fourth branch 14 is connected to the third branch 13 located between the second control valve 10 and the second check valve 12.

[0038] Furthermore, a third control valve 15 is provided on the fourth branch 14, which controls the flow direction of the refrigerant in the fourth branch 14 toward the second one-way valve 12. In addition, in this embodiment 2, the third control valve 15 is preferably a solenoid valve, which controls the flow of refrigerant in the fourth branch 14 by opening and closing the solenoid valve.

[0039] Based on the variable branching structure of Embodiment 2, when the refrigerant circuit of the heat pump chiller is in heating mode, the heat exchanger body 6 acts as an evaporator. The refrigerant inside the heat exchanger body 6 absorbs heat uniformly in each heat exchange path. At this time, the first control valve 11 can be controlled to be in the conducting state, while the third control valve 15 is in the closed state. The refrigerant flow process of the heat exchanger in Embodiment 2 in heating mode is basically the same as that of the heat exchanger in Embodiment 1 in heating mode. The refrigerant flows into the branching component 5 through the first one-way valve 9, and then is evenly distributed into the six second branches 7 through the branching component 5. The refrigerant enters the six heat exchange paths of the heat exchanger body 6 through the second branches 7, and after sufficient heat exchange in the heat exchange paths, it flows to the six first branches 8 respectively. Since the first control valve 11 is conducting and the third control valve 15 is closed, the second control valve 10 flows unidirectionally toward the first control valve 11. At this time, the six first branches 8 converge at the first parallel end 801 and flow into the refrigerant circuit for circulation. During this stage, the heat exchanger body is divided into six heat exchange channels, and the refrigerant is evenly distributed to these six channels for uniform heat absorption, thereby improving its heat exchange efficiency. It should be noted that due to the flow resistance of the refrigerant circuit, the refrigerant flowing into the third branch 13 cannot pass through the second one-way valve 12 normally, and in this state, there is basically no refrigerant flow in the third branch 13.

[0040] In this embodiment 2, when the refrigerant circuit of the heat pump chiller is in cooling mode, and the compressor is in a low-frequency operating state, the first control valve 11 can be controlled to be in the conducting state, while the third control valve 15 is in the closed state. When the refrigerant flows in the refrigerant circuit, since the refrigerant can pass through the first control valve 11 but cannot pass through the second control valve 10 in the reverse direction, and the third control valve 15 is also in the closed state, the refrigerant can only be evenly distributed through the five first branches 8 (i.e., branches 8.1~8.5), and then flow into the heat exchange passage of the heat exchanger body 6. It is then conducted to the flow divider 5 through the five second branches 7 (i.e., branches 7.1~7.5). Since the first one-way valve 9 blocks in the reverse direction, the refrigerant in the flow divider 5 cannot flow directly to the refrigerant circuit. Therefore, the refrigerant in the flow divider 5 flows back into the heat exchange passage of the heat exchanger body through the last second branch 7 (i.e., branch 7.6), and then flows to the third branch 13 through the last first branch 8 (i.e., branch 8.6), and finally merges into the refrigerant circuit through the third branch 13. Similar to the heat exchanger in Example 1, the variable branching structure in Example 2 addresses the issue of low refrigerant circulation and slow flow rate during low-frequency operation of the variable frequency compressor. To avoid insufficient heat exchange due to excessive branching leading to low flow rates or short flow paths in individual branches, the variable branching structure forms a flow structure with 5 branching paths and 1 confluence path. This reduces the number of refrigerant branching paths while increasing the flow length of each individual branch, balancing flow rate and subcooling. It avoids heat waste at low flow rates, ensuring sufficient refrigerant flow rate within the heat exchange path and further reducing temperature for higher subcooling. This fully utilizes the heat exchange area of ​​the heat exchanger, improving refrigeration efficiency.

[0041] In cooling mode, when the compressor operates at high frequency, the first control valve 11 can be controlled to be closed, and the third control valve 15 to be open. When refrigerant flows in the refrigerant circuit, since the refrigerant can pass through but not through the first control valve 11, it is first evenly distributed by the three first branches 8 (i.e., branches 8.1 to 8.3), and then flows into the heat exchange passage of the heat exchanger body 6. It is then conducted to the distribution element 5 through the three second branches 7 (i.e., branches 7.1 to 7.3). Due to the reverse obstruction of the first one-way valve 9, the refrigerant in the distribution element 5 cannot flow directly to the refrigerant circuit. Therefore, the refrigerant in the distribution element 5 is evenly distributed to the three second branches 7. (i.e., branches 7.4~7.6) and flow back into the heat exchange channel of the heat exchanger body. The refrigerant is then evenly distributed to the three first branches 8 (i.e., branches 8.4~8.6). Since the second control valve 10 blocks the refrigerant from branches 8.4 and 8.5, while the third control valve 15 is open, the refrigerant from branches 8.4 and 8.5 flows to the third branch 13 via the fourth branch 14, while the refrigerant from branch 8.6 flows directly to the third branch 13, ultimately converging into the refrigerant circuit via the third branch 13. Under high-frequency operation, the refrigerant's residence time in the heat exchange passages of the heat exchanger body is short. Therefore, the three heat exchange passages located at the top and the three at the bottom can be combined to form three evenly distributed branches, significantly increasing the flow length of each branch and extending the refrigerant's flow path within the heat exchanger body. This prolongs the heat exchange time, ensuring sufficient condensation of the refrigerant at high flow rates and maximizing cooling efficiency.

[0042] Similarly, when the refrigerant circuit of the heat pump chiller is in cooling mode, the heat pump chiller can also use a fixed-frequency compressor to control the refrigerant flow. Its state is the same as that of the variable-frequency compressor in high-frequency operation. The amount of refrigerant circulating is large and the flow rate is high. At this time, the corresponding control process and refrigerant flow process are basically the same as those of the variable-frequency compressor in high-frequency operation.

[0043] Example 3: In addition, this embodiment 3 also discloses a heat pump chiller unit, which includes a compressor 1, a four-way reversing valve 2, a first heat exchanger 3, a throttle valve 4 and a second heat exchanger connected in sequence to form a refrigerant circuit, wherein the second heat exchanger adopts the variable branch structure of embodiment 1.

[0044] like Figure 3As shown, when the heat pump chiller unit in embodiment 3 is running in heating mode, compressor 1 can be any compressor, such as a fixed-frequency compressor or a variable-frequency compressor. The refrigerant sequentially passes through compressor 1, four-way reversing valve 2, first heat exchanger 3, throttle valve 4, and first one-way valve 9 into the distribution component 5, where it is evenly distributed to six second branches 7. It then flows into the second heat exchanger, i.e., the heat exchanger body 6. Afterward, the refrigerant converges through the six first branches and flows into the four-way reversing valve 2, finally returning to compressor 1. During this process, the second heat exchanger evenly divides the refrigerant into six branches, ensuring uniform heat absorption in each branch of the second heat exchanger during heating, thus improving its heat exchange efficiency.

[0045] like Figure 4 As shown, when the heat pump chiller unit in embodiment 3 is running in cooling mode, compressor 1 can be operated at a low frequency using a variable frequency compressor. At this time, the refrigerant sequentially passes through compressor 1, four-way reversing valve 2, and flows into the second heat exchanger through five first branches 8. Subsequently, the refrigerant converges into the distribution component 5 through five second branches 7. The refrigerant in the distribution component 5 then flows back into the second heat exchanger through one second branch 7, and then flows into the third branch 13 through one first branch 8. Afterward, the refrigerant sequentially passes through the throttling valve 4, the first heat exchanger 3, and the four-way reversing valve 2, finally returning to compressor 1. During this process, the refrigerant passes through the second heat exchanger twice and finally exits through one first branch 8. This reduces the number of condensation branches in the second heat exchanger during cooling, while also extending the refrigerant's flow time within the second heat exchanger, ensuring sufficient condensation and improving its heat exchange efficiency.

[0046] like Figure 5 As shown, when the heat pump chiller unit in embodiment 3 is running in cooling mode, compressor 1 can be a fixed-frequency compressor or a variable-frequency compressor operating at a high frequency. At this time, the refrigerant passes sequentially through compressor 1, four-way reversing valve 2, and flows into the second heat exchanger through three first branches 8. Subsequently, the refrigerant converges into the distribution element 5 through three second branches 7. The refrigerant in the distribution element 5 then flows back into the second heat exchanger through the three second branches 7, and flows into the third branch 13 through the three first branches 8. The refrigerant is collected through the third branch 13 and sequentially passes through the throttling valve 4, the first heat exchanger 3, and the four-way reversing valve 2, finally returning to compressor 1. During this process, the refrigerant also passes through the second heat exchanger twice, ultimately exiting the second heat exchanger through the three first branches 8. This process further reduces the number of condensing branches in the second heat exchanger during cooling and ensures that the length of a single condensing branch is increased, meeting the refrigerant subcooling requirements and ensuring sufficient condensation of the refrigerant in the second heat exchanger, thus improving its heat exchange efficiency.

[0047] Example 4: Furthermore, this embodiment 4 further discloses a heat pump chiller unit, which includes a compressor 1, a four-way reversing valve 2, a first heat exchanger 3, a throttle valve 4 and a second heat exchanger connected in sequence to form a refrigerant circuit, wherein the second heat exchanger adopts the variable branch structure of embodiment 2.

[0048] like Figure 6 As shown, when the heat pump chiller unit in embodiment 4 is running in heating mode, compressor 1 can be any compressor, such as a fixed-frequency compressor or a variable-frequency compressor. The refrigerant sequentially passes through compressor 1, four-way reversing valve 2, first heat exchanger 3, throttle valve 4, and first one-way valve 9 into the distribution component 5, where it is evenly distributed to six second branches 7. Subsequently, the refrigerant flows into the second heat exchanger, i.e., the heat exchanger body 6. Afterward, the refrigerant converges through the six first branches and flows into the four-way reversing valve 2, finally returning to compressor 1. During this process, the second heat exchanger evenly divides the refrigerant into six branches, ensuring uniform heat absorption in each branch of the second heat exchanger during heating, thus improving its heat exchange efficiency.

[0049] like Figure 7 As shown, when the heat pump chiller unit in embodiment 4 is running in cooling mode, compressor 1 can be operated at a low frequency using a variable frequency compressor. At this time, the refrigerant sequentially passes through compressor 1, four-way reversing valve 2, and flows into the second heat exchanger through five first branches 8. Subsequently, the refrigerant converges into the distribution element 5 through five second branches 7. The refrigerant in the distribution element 5 then flows back into the second heat exchanger through one second branch 7, and then flows into the third branch 13 through one first branch 8. Afterward, the refrigerant sequentially passes through the expansion valve 4, the first heat exchanger 3, and the four-way reversing valve 2, finally returning to compressor 1. During this process, the refrigerant passes through the second heat exchanger twice and finally exits through one first branch 8. This reduces the number of condensation branches in the second heat exchanger during cooling, while also extending the refrigerant's flow time within the second heat exchanger, ensuring sufficient condensation and improving its heat exchange efficiency.

[0050] like Figure 8As shown, when the heat pump chiller unit in embodiment 4 is running in cooling mode, compressor 1 can be a fixed-frequency compressor or a variable-frequency compressor operating at a high frequency. At this time, the refrigerant passes sequentially through compressor 1, four-way reversing valve 2, and flows into the second heat exchanger through three first branches 8. Subsequently, the refrigerant converges into the distribution component 5 through three second branches 7. The refrigerant in the distribution component 5 then flows back into the second heat exchanger through the three second branches 7, and flows through the three first branches 8 to the third branch 13 and the fourth branch 14 respectively. After being collected through the third branch 13 and the fourth branch 14, the refrigerant passes sequentially through the throttling valve 4, the first heat exchanger 3, and the four-way reversing valve 2, finally returning to compressor 1. During this process, the refrigerant also passes through the second heat exchanger twice, and finally flows out of the second heat exchanger through three first branches. This process further reduces the number of condenser branches in the second heat exchanger during refrigeration and ensures that the length of a single condenser branch is increased, which can meet the refrigerant subcooling requirements, ensure that the refrigerant is fully condensed in the second heat exchanger, and improve its heat exchange efficiency.

[0051] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A variable-circuit structure suitable for heat exchangers, used to supply refrigerant to the heat exchanger in heating or cooling modes, characterized in that, The heat exchanger body, the flow divider, the first control valve, the second control valve, the first branch, and the second branch; The heat exchanger body is provided with a plurality of heat exchange channels, one end of each of the heat exchange channels is connected to the first branch, and the other end of the heat exchange channel is connected to the second branch; The first control valve is located between the first parallel unit and the second parallel unit, and the second control valve is arranged in the second parallel unit. The second control valve and the first one-way valve are provided with a third branch, the third branch is provided with a second one-way valve, and the flow direction of the refrigerant in the third branch is controlled by the second one-way valve.

2. The variable split structure for heat exchanger applications of claim 1, wherein, The first control valve and the second control valve are both electromagnetic valves.

3. The variable split structure for heat exchanger applications of claim 1, wherein, When the heat exchanger is in a heating mode, the first control valve and the second control valve are both in a conduction state.

4. The variable split structure for heat exchanger applications of claim 3, wherein, When the heat exchanger is in a cooling mode, the first control valve is in a conduction state, and the second control valve is in an off state; or the first control valve is in an off state, and the second control valve is in a conduction state.

5. The variable split structure for heat exchanger applications of claim 3, wherein, The second control valve is provided with a fourth branch in parallel, one end of the fourth branch is connected to the second parallel unit between the first control valve and the second control valve, the other end of the fourth branch is connected to the third branch between the second control valve and the second one-way valve, and the fourth branch is provided with a third control valve.

6. The variable split structure for heat exchanger applications of claim 2, wherein, The first control valve and the third control valve are electromagnetic valves, the second control valve is a one-way valve, and the flow direction of the refrigerant of the second control valve is towards the first control valve.

7. The variable split structure for heat exchanger applications of claim 6, wherein, When the heat exchanger is in a heating mode, the first control valve is in a conduction state, and the third control valve is in an off state.

8. The variable split structure for heat exchanger applications of claim 7, wherein, When the heat exchanger is in a cooling mode, the first control valve is in a conduction state, and the third control valve is in an off state; or the first control valve is in an off state, and the third control valve is in a conduction state.

9. The variable split structure for heat exchanger applications of claim 7, wherein, The second heat exchanger adopts the variable flow distribution structure according to any one of claims 1-9.

10. A heat pump water chiller comprising a compressor, a four-way reversing valve, a first heat exchanger, a throttling valve and a second heat exchanger connected in series to form a refrigerant circuit, characterized in that, ​

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