Heat pump system and control method of heat pump system

Abstract

The invention provides a heat pump system and a control method of the heat pump system, the heat pump system comprises a compression assembly, a first heat exchange piece, a first throttling piece and a second heat exchange piece which are sequentially arranged in a communicating mode, the compression assembly comprises a first compressor and a second compressor which are arranged in a communicating mode, and an outlet of the first compressor communicates with an inlet of the second compressor. The heat pump system further comprises a third heat exchange piece and a second throttling piece, the third heat exchange piece comprises a first heat exchange flow channel and a second heat exchange flow channel which achieve the heat exchange function, an inlet of the first heat exchange flow channel communicates with an outlet of the first heat exchange piece, and an outlet of the second heat exchange flow channel communicates with an inlet of the second compressor. An outlet of the second throttling piece communicates with an inlet of the second heat exchange runner. The pipeline structure in the heat pump system comprises a first pipeline and a second pipeline which are connected to an outlet of a first heat exchange flow channel in parallel, the first pipeline communicates with an inlet of a first throttling element, and a second throttling element communicates with a second heat exchange flow channel through a second pipeline.

Description

Technical Field

[0001] The present application relates to the technical field of thermal management, and particularly to a heat pump system and a control method thereof. Background Art

[0002] A heat pump system is a device that efficiently utilizes low-grade heat energy from the outside world. By means of a reverse cycle, it transfers heat from a low-temperature object to a high-temperature object, and can achieve a large heat supply with only a small amount of electric energy consumption. Compared with traditional coal-fired systems, it has significant energy-saving effects, and can automatically adjust the heating temperature according to the ambient temperature, with good comfort and environmental protection. Summary of the Invention

[0003] Embodiments of the present application provide a heat pump system and a control method thereof, which can improve the performance of the heat pump system.

[0004] Embodiments of the present application provide a heat pump system, which includes a compression assembly, a first heat exchanger, a first throttling member, and a second heat exchanger connected in sequence. The compression assembly includes a first compressor and a second compressor connected in communication. The outlet of the first compressor is connected to the inlet of the second compressor. The heat pump system further includes a third heat exchanger and a second throttling member. The third heat exchanger includes a first heat exchange channel and a second heat exchange channel for realizing heat exchange functions. The inlet of the first heat exchange channel is connected to the outlet of the first heat exchanger, the outlet of the second heat exchange channel is connected to the inlet of the second compressor, and the outlet of the second throttling member is connected to the inlet of the second heat exchange channel. Among them, the pipeline structure in the heat pump system includes a first pipeline and a second pipeline connected in parallel to the outlet of the first heat exchange channel. The first pipeline is connected to the inlet of the first throttling member, and the second throttling member is connected to the second heat exchange channel through the second pipeline.

[0005] In some embodiments, the heat pump system further includes a first control member. The first pipeline and the second pipeline are connected in parallel to the outlet of the first heat exchange channel through the first control member;

[0006] Among them, the first control member is used to adjust the flow rate of the fluid entering the first pipeline and the second pipeline.

[0007] In some embodiments, the first throttling member includes an ejector. The inlet of the ejector includes a first inlet end and a second inlet end. The first inlet end is connected to the first pipeline, and the second inlet end is connected to the outlet of the second heat exchanger;

[0008] The heat pump system further includes a gas-liquid separator. The outlet of the ejector is connected to the inlet of the gas-liquid separator. The outlet of the gas-liquid separator includes a first outlet end and a second outlet end. The first outlet end is connected to the inlet of the first compressor, and the second outlet end is connected to the inlet of the second heat exchanger.

[0009] In some embodiments, the heat pump system further includes a cooling member, the cooling member includes a third heat exchange flow path and a fourth heat exchange flow path for realizing a heat exchange function, an inlet of the third heat exchange flow path is communicated with an outlet of the first heat exchange flow path, and the first pipeline and the second pipeline are connected in parallel to an outlet of the third heat exchange flow path;

[0010] Wherein, an inlet of the fourth heat exchange flow path and an inlet of the second heat exchange member are connected in parallel to a second outlet end, and an outlet of the fourth heat exchange flow path and an outlet of the ejector are connected in parallel to an inlet of the gas-liquid separator.

[0011] In some embodiments, the heat pump system further includes a second control member, and an inlet of the fourth heat exchange flow path and an inlet of the second heat exchange member are connected in parallel to the second outlet end through the second control member;

[0012] Wherein, the second control member is used for adjusting the fluid ratio entering the fourth heat exchange flow path and the second heat exchange member.

[0013] In some embodiments, the heat pump system further includes a third throttling member, and an inlet of the second heat exchange member is communicated with the second control member through the third throttling member.

[0014] In some embodiments, the heat pump system further includes a first one-way member, and the first one-way member is arranged between an outlet of the second heat exchange flow path and an inlet of the second compressor; and / or,

[0015] The heat pump system further includes a third control member and a second one-way member, an outlet of the fourth heat exchange flow path and an outlet of the ejector are connected in parallel to an inlet of the gas-liquid separator through the third control member, and the second one-way member is arranged between an outlet of the fourth heat exchange flow path and an inlet of the gas-liquid separator; and / or,

[0016] The heat pump system further includes a third control member and a third one-way member, an outlet of the fourth heat exchange flow path and an outlet of the ejector are connected in parallel to an inlet of the gas-liquid separator through the third control member, and the third one-way member is arranged between the third control member and an inlet of the gas-liquid separator.

[0017] In some embodiments, a driving member is further included, and the driving member is arranged between the second outlet end and the fourth heat exchange flow path.

[0018] In a second aspect, an embodiment of the present application provides a control method for a heat pump system, which is used to control the heat pump system in any of the foregoing embodiments. The heat pump system further includes a first control member, and the first pipeline and the second pipeline are connected in parallel to an outlet of the first heat exchange flow path through the first control member; the control method includes:

[0019] Adjust the first control member to change the fluid flow rates in the first pipeline and the second pipeline;

[0020] Adjust the opening degree of the second throttling member to enable the heat pump system to be in a first operating state. In the first operating state, the fluid located at the outlet of the second heat exchange flow path is in a saturated gaseous state.

[0021] In some embodiments, the first throttling member includes an ejector, the heat pump system further includes a gas-liquid separator and a second control member; after adjusting the opening degree of the second throttling member, the control method further includes:

[0022] Determine whether the liquid level in the gas-liquid separator changes;

[0023] When the liquid level in the liquid level separator changes, adjust the second control member to change the fluid flow rates entering the inlet of the fourth heat exchange flow path and the inlet of the second heat exchange member.

[0024] In some embodiments, the first throttling member includes an ejector, the heat pump system further includes a gas-liquid separator and a driving member, before controlling the first control member, the control method further includes:

[0025] Control the operation of the first compressor and the second compressor;

[0026] Control the operation of the driving member so that the fluid at the outlet of the fourth heat exchange flow path has the same pressure as the fluid at the outlet of the ejector.

[0027] In some embodiments, the first throttling member includes an ejector, the heat pump system further includes a gas-liquid separator and a second control member; after adjusting the opening degree of the second throttling member, the control method further includes:

[0028] Determine whether the ambient temperature for heat exchange with the second heat exchange member changes;

[0029] When the ambient temperature changes, adjust the opening degree of the third throttling member to change the evaporation temperature of the fluid in the second heat exchange member;

[0030] Adjust at least one of the first control member, the second control member, and the second throttling member so that the heat pump system is in a first operating state.

[0031] The embodiments of the present application provide a heat pump system and a control method for the heat pump system. A third heat exchange member and a second throttling member are added in the heat pump system. Through the heat exchange between the first heat exchange flow path and the second heat exchange flow path, the temperature of the fluid entering the first throttling member can be reduced, thereby increasing the temperature difference of the fluid between the outlet of the second compressor and the inlet of the first throttling member, improving the cooling effect and operating performance of the heat pump system. In addition, the outlet of the second heat exchange flow path in the third heat exchange member can also be connected to the inlet of the second compressor, thereby reducing the temperature of the fluid at the inlet of the second compressor, achieving the intermediate cooling and gas supplementing effects on the compression assembly, reducing the energy consumption of the second compressor, and thus improving the performance of the compression assembly. Description of the Drawings

[0032] To more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for the embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0033] Figure 1 is a schematic structural diagram of a heat pump system provided by an embodiment of the present application;

[0034] Figure 2 is a schematic structural diagram of another heat pump system provided by an embodiment of the present application;

[0035] Figure 3 is a schematic structural diagram of still another heat pump system provided by an embodiment of the present application;

[0036] Figure 4 is Figure 3 the temperature-entropy diagram corresponding to the heat pump system shown;

[0037] Figure 5 is a flowchart of a control method for a heat pump system provided by an embodiment of the present application;

[0038] Figure 6 is a flowchart of a control method for still another heat pump system provided by an embodiment of the present application;

[0039] Figure 7 is a flowchart of a control method for still another heat pump system provided by an embodiment of the present application;

[0040] Figure 8 is a flowchart of a control method for still another heat pump system provided by an embodiment of the present application.

[0041] Marking description:

[0042] 10. Compression assembly; 11. First compressor; 12. Second compressor;

[0043] 21. First heat exchanger; 22. Second heat exchanger; 23. Third heat exchanger; 231. First heat exchange flow channel; 232. Second heat exchange flow channel;

[0044] 31. First throttling element; 311. First inlet end; 312. Second inlet end; 32. Second throttling element; 33. Third throttling element;

[0045] 40. Cooling element; 41. Third heat exchange flow channel; 42. Fourth heat exchange flow channel;

[0046] 51. First pipeline; 52. Second pipeline;

[0047] 61. First control member; 62. Second control member; 63. Third control member; 64. First one-way member; 65. Second one-way member; 66. Third one-way member; 67. Fourth control member;

[0048] 70. Gas-liquid separator; 71. First outlet end; 72. Second outlet end;

[0049] 80. Driving member;

[0050] 90. Injector. Detailed implementation manners

[0051] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, rather than to limit the present application. For those skilled in the art, the present application can be implemented without some of these specific details. The following description of the embodiments is only intended to provide a better understanding of the present application by showing examples of the present application.

[0052] It should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, the elements defined by the statement "comprising..." do not exclude the existence of additional identical elements in the process, method, article or device comprising the said elements.

[0053] In a heat pump system, the return water temperature is an important parameter during the operation of the system, which often affects the operation performance of the system. Specifically, the heat pump system uses a refrigerant to absorb heat from a low-temperature object, and after heating, releases the heat to a high-temperature object, so as to achieve purposes such as heating. Among them, the high-temperature object mentioned here can be a coolant, and the return water temperature refers to the temperature of the coolant returned from the radiator or heating device during the heating process, in other words, the temperature of the coolant returned from the heat user.

[0054] Furthermore, the coolant and the refrigerant need to exchange heat through a heat exchange component so that the coolant absorbs some heat. On this basis, if the return water temperature is too high, the heat exchange amount between the refrigerant and the coolant will decrease, resulting in too high a temperature of the refrigerant leaving the heat exchange component. Furthermore, the enthalpy difference of the refrigerant at the inlet and outlet of the heat exchange component will decrease, leading to a decline in the performance of the entire heat pump system.

[0055] In view of the above problems, on the one hand, please refer to Figure 1 , an embodiment of the present application provides a heat pump system, which includes a compression component 10, a first heat exchange component 21, a first throttling component 31, and a second heat exchange component 22 connected in sequence. The compression component 10 includes a first compressor 11 and a second compressor 12 connected in communication. The outlet of the first compressor 11 is connected to the inlet of the second compressor 12.

[0056] The heat pump system further includes a third heat exchange component 23 and a second throttling component 32. The third heat exchange component 23 includes a first heat exchange flow channel 231 and a second heat exchange flow channel 232 that implement the heat exchange function. The inlet of the first heat exchange flow channel 231 is connected to the outlet of the first heat exchange component 21, and the outlet of the second heat exchange flow channel 232 is connected to the inlet of the second compressor 12. The outlet of the second throttling component 32 is connected to the inlet of the second heat exchange flow channel 232. Among them, the pipeline structure in the heat pump system includes a first pipeline 51 and a second pipeline 52 connected in parallel to the outlet of the first heat exchange flow channel 231. The first pipeline 51 is connected to the inlet of the first throttling component 31, and the second throttling component 32 is connected to the second heat exchange flow channel 232 through the second pipeline 52.

[0057] A heat pump system is an energy-saving device that uses high-level energy (such as electric energy) to drive and transfers the heat energy of a low-level heat source (such as air, water, or soil) to a high-level heat source. Optionally, the heat pump system provided by the embodiment of the present application can be an air source heat pump system, that is, the heat pump system can absorb heat from the external air environment and transfer it to the heat user to meet the needs of heating and the like.

[0058] The heat pump system includes a pipeline structure and multiple functional components. The pipeline structure is connected to the functional components to meet the conduction needs between different functional components. During the operation of the heat pump system, the pipeline structure and multiple functional components can jointly form a loop system for fluid circulation. Among them, the fluid mentioned here is the refrigerant.

[0059] Optionally, the fluid in the heat pump system can be carbon dioxide, that is, the heat pump system can be a transcritical carbon dioxide heat pump system. Based on the unique physical properties of supercritical carbon dioxide, at high temperature and high pressure, supercritical carbon dioxide has excellent corrosion resistance and low viscosity. In addition, under the same installed capacity, it has a smaller volume, lighter weight, higher power generation efficiency, and can help reduce carbon emissions. Therefore, it has advantages such as high efficiency and flexibility and has great potential in the heating field.

[0060] The compression assembly 10, the first heat exchanger 21, the first throttling element 31, the second heat exchanger 22, and the third heat exchanger 23 are all functional components in the heat pump system. The compression assembly 10 is a driven fluid machine that raises low-pressure gas to high-pressure gas. The compression assembly 10 includes a first compressor 11 and a second compressor 12 connected in communication. The first compressor 11 and the second compressor 12 together form a bipolar compression, and bipolar compression is a compression method that realizes the compression process in two steps. Specifically, bipolar compression means that the gaseous fluid is first compressed to an intermediate pressure by a low-pressure stage compressor (i.e., the first compressor 11), and then compressed to a higher pressure by a high-pressure stage compressor (i.e., the second compressor 12). Among them, although the embodiments of the present application show a two-compressor structure composed of two compressors, according to different actual needs, the two compressors can also be replaced by a single two-stage compressor to achieve bipolar compression, and the embodiments of the present application do not limit this.

[0061] The first heat exchanger 21 is a component in the heat pump system that acts as a cooler and is used to realize the heat exchange between the refrigerant and the coolant. Optionally, the coolant can include cooling water. The inlet of the first heat exchanger 21 is connected to the outlet of the second compressor 12, and the outlet of the first heat exchanger 21 is connected to the inlet of the first heat exchange channel 231. Among them, the first heat exchanger 21 includes a fifth heat exchange channel and a sixth heat exchange channel that realize the heat exchange function. The fifth heat exchange channel is used for the refrigerant to flow, and the sixth heat exchange channel is used for the coolant to flow. On this basis, the "inlet of the first heat exchanger 21" mentioned in the embodiments of the present application refers to: the inlet of the fifth heat exchange channel. Similarly, the "outlet of the first heat exchanger 21" refers to: the outlet of the fifth heat exchange channel. In Figure 1 it, the fifth heat exchange channel is shown in solid lines, while the sixth heat exchange channel is shown in dotted lines.

[0062] The first throttling member 31 is a component that plays a throttling and expansion role in the heat pump system, and the second heat exchange member 22 is a component that plays the role of an evaporator in the heat pump system. Through the mutual cooperation of the compression assembly 10, the first heat exchange member 21, the first throttling member 31, and the second heat exchange member 22, the fluid can achieve four steps of compression, cooling, throttling, and evaporation in the heat pump system. Through the continuous cycle of these four steps, the heat pump system can absorb heat from the surrounding ambient air and transfer it to the coolant, achieving effects such as heating.

[0063] Regarding the specific structural form of the first throttling member 31, the embodiments of the present application do not limit it. Optionally, the first throttling member 31 may include a throttle valve. A throttle valve is a valve that controls the fluid flow rate and pressure by changing the cross-sectional area of the channel. The inlet of the throttle valve is connected to the outlet of the first heat exchange member 21, and the outlet of the throttle valve is connected to the inlet of the second heat exchange member 22.

[0064] For the second heat exchange member 22, optionally, when the heat pump system is an air source heat pump system, the second heat exchange member 22 can be used for heat exchange with the external environment space, thereby absorbing part of the heat in the external environment space by means of the second heat exchange member 22 and achieving the absorption of the heat energy of the low-temperature heat source.

[0065] In addition to the compression assembly 10, the first heat exchange member 21, the first throttling member 31, and the second heat exchange member 22, the heat pump system in the embodiments of the present application further adds a third heat exchange member 23 and a second throttling member 32. Similar to the first heat exchange member 21, the third heat exchange member 23 is a component used to achieve the heat exchange function and includes two heat exchange channels. However, the difference is that the fluids in the first heat exchange channel 231 and the second heat exchange channel 232 in the third heat exchange member 23 are the same medium. Optionally, the third heat exchange member 23 includes a subcooler. In Figure 1 it, the first heat exchange channel 231 is shown in the form of a thin broken line, and the second heat exchange channel 232 is shown in the form of a thick straight line.

[0066] Similar to the first throttling member 31, the second throttling member 32 can also play a throttling role. Optionally, the second throttling member 32 includes a throttle valve. The outlet of the second throttling member 32 is connected to the inlet of the second heat exchange channel 232, that is, the second throttling member 32 can throttle the fluid entering the second heat exchange channel 232.

[0067] Normally, the fluid temperatures at the outlet of the first heat exchange member 21 and the inlet of the first throttling member 31 are usually the same or similar. However, in the embodiments of the present application, due to the presence of the third heat exchange member 23 and the second throttling member 32, the fluid temperature at the inlet of the first throttling member 31 is lower than the fluid temperature at the outlet of the first heat exchange member 21, so as to improve the overall performance of the heat pump system.

[0068] Specifically, the inlet of the first heat exchange flow path 231 is connected to the outlet of the first heat exchange member 21, and the outlet of the first heat exchange flow path 231 is connected in parallel to the first throttling member 31 and the second throttling member 32 through the first pipeline 51 and the second pipeline 52. On this basis, taking the fluid in the heat pump system as carbon dioxide, the high-temperature and high-pressure carbon dioxide is split at the outlet of the first heat exchange flow path 231. A part enters into the first throttling member 31 through the first pipeline 51, and the other part enters into the second throttling member 32 through the second pipeline 52, and is transformed into low-pressure two-phase carbon dioxide under the throttling effect and enters into the second heat exchange flow path 232. Thus, the temperature of the carbon dioxide in the first heat exchange flow path 231 is usually higher than that of the carbon dioxide in the second heat exchange flow path 232. Therefore, the carbon dioxide in the second heat exchange flow path 232 will absorb heat and evaporate, and reduce the temperature of the carbon dioxide in the first heat exchange flow path 231. After that, the carbon dioxide after absorbing heat and evaporating converges with the carbon dioxide at the outlet of the first compressor 11 and enters into the second compressor 12 together.

[0069] Due to the heat absorption effect of the carbon dioxide in the second heat exchange flow path 232, the temperature of the carbon dioxide at the outlet of the first heat exchange flow path 231 is lower than that at the inlet of the first heat exchange flow path 231. Further, since the fluid temperature at the outlet of the first heat exchange member 21 is usually the same as or close to the fluid temperature at the inlet of the first heat exchange flow path 231. Therefore, the fluid temperature at the outlet of the first heat exchange flow path 231 is also lower than the fluid temperature at the outlet of the first heat exchange member 21, which helps to increase the fluid temperature difference between the outlet of the second compressor 12 and the inlet of the first throttling member 31, so as to improve the cooling effect of the system, and thus helps to improve the performance of the heat pump system.

[0070] In addition, the outlet of the second heat exchange flow path 232 is connected to the inlet of the second compressor 12, that is, the outlet of the first compressor 11 and the outlet of the second heat exchange flow path 232 are connected in parallel to the inlet of the second compressor 12. Thus, the fluid at the outlet of the second heat exchange flow path 232 and the fluid at the outlet of the first compressor 11 will converge at the inlet of the second compressor 12, and the fluid temperature at the outlet of the first compressor 11 is usually higher than the fluid temperature at the outlet of the second heat exchange flow path 232. Therefore, connecting the outlet of the second heat exchange flow path 232 to the inlet of the second compressor 12 helps to reduce the fluid temperature at the inlet of the second compressor 12, so as to achieve the intermediate cooling of the compression assembly 10, reduce the energy consumption of the second compressor 12, and improve the performance of the compression assembly 10.

[0071] It should be noted that in addition to the above-mentioned functional components, other component structures can also be provided in the heat pump system. Regarding the specific composition of the heat pump system, the embodiments of the present application do not make any limitations. As long as the heat pump system includes at least a compression assembly 10, a first heat exchanger 21, a first throttling member 31, a second heat exchanger 22, and a third heat exchanger 23, and these functional components can be arranged and designed according to the above content.

[0072] In addition, the "connection" mentioned in the embodiments of the present application means that for two components, the inlet of one component is connected to the outlet of the other component through a pipeline structure, but it does not limit that the two components are adjacent components. For example, taking the inlet of the first heat exchange channel 231 being connected to the outlet of the first heat exchanger 21 as an example, the "connection" mentioned here means that the inlet of the first heat exchange channel 231 is connected to the outlet of the first heat exchanger 21 through a pipeline structure. According to different actual needs, other functional components may not be provided on the pipeline structure for connecting the inlet of the first heat exchange channel 231 and the outlet of the first heat exchanger 21. In this case, the third heat exchanger 23 and the first heat exchanger 21 are two adjacent components. Or other functional components may also be provided on this pipeline structure. For example, control switches such as valves can be provided, or detection elements such as flow meters and pressure gauges can be provided. In this case, the third heat exchanger 23 and the first heat exchanger 21 are not two adjacent components. The "connection" mentioned in other embodiments of the present application is the same as this, and will not be elaborated later.

[0073] In some alternative embodiments, the heat pump system further includes a fourth control member 67. The outlet of the first compressor 11 and the outlet of the fourth heat exchange channel 42 are connected in parallel to the inlet of the second compressor 12 through the fourth control member 67. Among them, the fourth control member 67 may include a three-way valve.

[0074] In summary, in the embodiments of the present application, a third heat exchanger 23 and a second throttling member 32 are added to the heat pump system. Through the heat exchange between the first heat exchange channel 231 and the second heat exchange channel 232, the temperature of the fluid entering the first throttling member 31 can be reduced, thereby increasing the temperature difference of the fluid between the outlet of the second compressor 12 and the inlet of the first throttling member 31, improving the cooling effect and operating performance of the heat pump system. In addition, the outlet of the second heat exchange channel 232 in the third heat exchanger 23 can also be connected to the inlet of the second compressor 12, thereby reducing the temperature of the fluid at the inlet of the second compressor 12, achieving the intermediate cooling and gas replenishing effects on the compression assembly 10, reducing the energy consumption of the second compressor 12, and thus improving the performance of the compression assembly 10.

[0075] Furthermore, by adjusting the opening degree of the second flow component 32, it is possible to help adjust the evaporation temperature of the fluid in the second heat exchange flow path 232 of the third heat exchange component 23, enabling the heat pump system to operate in an optimal state. Here, the "optimal state" mentioned refers to the ideal operating state when the coefficient of performance (COP) of the heat pump system reaches its maximum value under the current ambient operating conditions.

[0076] It should be noted that the maximum value of the coefficient of performance needs to be specifically determined based on the actual operating conditions corresponding to the operation of the heat pump system and the numerical values displayed by the flow meters at specific points in the heat pump system. It can be directly measured through experiments or calculated through simulation methods. The embodiments of the present application do not limit this. Exemplarily, when the coefficient of performance of the heat pump system is at its maximum value, the fluid at the outlet of the second heat exchange flow path 232 can be in a saturated gaseous state or slightly superheated state.

[0077] In some embodiments, as Figure 1 shown, the heat pump system further includes a first control component 61. The first pipeline 51 and the second pipeline 52 are connected in parallel to the outlet of the first heat exchange flow path 231 through the first control component 61. Among them, the first control component 61 is used to adjust the flow rate of the fluid entering the first pipeline 51 and the second pipeline 52.

[0078] The first control component 61 includes at least three ports, which are respectively used to communicate with the first pipeline 51, the second pipeline 52, and the outlet of the first heat exchange flow path 231. Optionally, the first control component 61 includes a three-way valve. Further, in the embodiments of the present application, in addition to realizing the parallel connection of the first pipeline 51 and the second pipeline 52 relative to the outlet of the first heat exchange flow path 231 to meet the basic operating requirements of the heat pump system, the first control component 61 can also play a role in adjusting the flow rate distribution. On this basis, the first control component 61 can be used to flexibly adjust the flow rate distribution of the first control component 61 for the first pipeline 51 and the second pipeline 52, so that the fluid in the heat pump system can be in an optimal flow rate distribution state. Here, the "optimal flow rate distribution state" mentioned refers to the flow rate distribution scheme corresponding to the heat pump system in the optimal state.

[0079] In some embodiments, please refer to Figure 2, the first - stage flow component 31 includes an ejector 90. The inlet of the ejector 90 includes a first inlet end 311 and a second inlet end 312. The first inlet end 311 is connected to the first pipeline 51, and the second inlet end 312 is connected to the outlet of the second heat - exchange component 22. The heat - pump system further includes a gas - liquid separator 70. The outlet of the ejector 90 is connected to the inlet of the gas - liquid separator 70. The outlet of the gas - liquid separator 70 includes a first outlet end 71 and a second outlet end 72. The first outlet end 71 is connected to the inlet of the first compressor 11, and the second outlet end 72 is connected to the inlet of the second heat - exchange component 22.

[0080] The ejector 90 is a hydrodynamic pump. The hydrodynamic pump has no mechanical transmission and mechanical working components. It uses the energy of another working fluid as a power source to transport low - energy fluid. Specifically, the inlet of the ejector 90 includes a first inlet end 311 and a second inlet end 312. The first inlet end 311 is the high - pressure inlet of the ejector 90. Part of the fluid at the outlet of the first heat - exchange channel 231 passes through the first pipeline 51 and enters the first inlet end 311 as the high - pressure main flow of the ejector 90. The second inlet end 312 is the low - pressure inlet of the ejector 90. The fluid at the outlet of the second heat - exchange component 22 enters the second inlet end 312 as the low - pressure secondary flow of the ejector 90 and is entrained under the action of the high - pressure main flow. After the entrainment is completed, a medium - pressure two - phase fluid leaves the ejector 90 through the outlet of the ejector 90 and enters the gas - liquid separator 70.

[0081] The inlet of the gas - liquid separator 70 is connected to the outlet of the ejector 90. The two - phase fluid leaving the outlet of the ejector 90 enters the gas - liquid separator 70 through the inlet of the gas - liquid separator 70. The outlet of the gas - liquid separator 70 includes a first outlet end 71 and a second outlet end 72. The first outlet end 71 is the gaseous outlet of the gas - liquid separator 70. The gaseous fluid in the gas - liquid separator 70 can leave the gas - pressure separator through the first outlet end 71 and enter the first compressor 11. The second outlet end 72 is the liquid outlet of the gas - liquid separator 70. The liquid fluid in the gas - liquid separator 70 can leave the gas - pressure separator through the second outlet end 72 and enter the second heat - exchange component 22.

[0082] Further, the fluid entering the second heat - exchange component 22 can absorb the heat in the external ambient air, and then enter the ejector 90 as the low - pressure secondary flow and be entrained and boosted in pressure. Thus, the setting of the ejector 90 can establish an effective power - recovery path between the high - pressure fluid and the low - pressure fluid, thereby improving the overall performance of the heat - pump system.

[0083] Specifically, if the first throttling member 31 includes a throttle valve, the outlet of the throttle valve communicates with the inlet of the second heat exchanger 22, and the outlet of the second heat exchanger 22 communicates with the inlet of the gas-liquid separator 70. In this case, the fluid pressure entering the inlet of the first compressor 11 often depends on the fluid pressure at the outlet of the second heat exchanger 22.

[0084] However, in the embodiment of the present application, the first throttling member 31 includes an ejector 90. The ejector 90 can also achieve a throttling effect. Different from the throttle valve, the outlet of the second heat exchanger 22 does not directly communicate with the inlet of the gas-liquid separator 70, but communicates with the second inlet end 312. On this basis, the fluid pressure entering the inlet of the first compressor 11 often depends on the fluid pressure at the outlet of the ejector 90, and the low-pressure fluid corresponding to the outlet of the second heat exchanger 22 is boosted by the ejector 90, so that the fluid pressure at the outlet of the ejector 90 is greater than the fluid pressure at the outlet of the second heat exchanger 22. Furthermore, the fluid pressure is increased before entering the inlet of the first compressor 11, so as to fully recover the expansion work by means of the ejector 90, reduce the overall power consumption of the compression assembly 10, and improve the overall performance of the heat pump system.

[0085] In some embodiments, please refer to Figure 3 , the heat pump system further includes a cooling member 40. The cooling member 40 includes a third heat exchange flow channel 41 and a fourth heat exchange flow channel 42 for realizing the heat exchange function. The inlet of the third heat exchange flow channel 41 communicates with the outlet of the first heat exchange flow channel 231, and the first pipeline 51 and the second pipeline 52 are connected in parallel to the outlet of the third heat exchange flow channel 41. Among them, the outlet of the fourth heat exchange flow channel 42 and the inlet of the second heat exchanger 22 are connected in parallel to the second outlet end 72, and the outlet of the fourth heat exchange flow channel 42 and the outlet of the ejector 90 are connected in parallel to the inlet of the gas-liquid separator 70.

[0086] The cooling member 40 is a component in the heat pump system that can heat the fluid in the fourth heat exchange flow channel 42 and cool down the fluid in the third heat exchange flow channel 41. Similar to the first heat exchanger 21, the second heat exchanger 22, and the third heat exchanger 23, the cooling member 40 itself can also achieve heat exchange. However, different from the first heat exchanger 21 and the second heat exchanger 22, the two heat exchange flow channels in the cooling member 40 are used to achieve heat exchange between the same fluids.

[0087] Specifically, the cooling member 40 includes a third heat exchange flow channel 41 and a fourth heat exchange flow channel 42. The fluid leaving the outlet of the first heat exchange flow channel 231 enters the third heat exchange flow channel 41 for heat exchange, and then is split into the first pipeline 51 and the second pipeline 52. The fluid leaving the second outlet end 72 of the gas-liquid separator 70 is split into the second heat exchange member 22 and the fourth heat exchange flow channel 42. The fluid that has completed heat exchange in the fourth heat exchange flow channel 42 will converge with the fluid at the outlet of the ejector 90 and enter the gas-liquid separator 70 together.

[0088] In this process, the fluids in the third heat exchange flow channel 41 and the fourth heat exchange flow channel 42 are the same medium, and the temperature of the fluid in the third heat exchange flow channel 41 is higher than that of the fluid in the fourth heat exchange flow channel 42. Therefore, the fluid in the third heat exchange flow channel 41 can release heat and cool down, so that the temperature of the fluid at the outlet of the third heat exchange flow channel 41 is lower than the temperature of the fluid at the inlet of the third heat exchange flow channel 41. In this way, the subcooler is used to further reduce the temperature of the high-pressure main stream fluid entering the ejector 90.

[0089] Next, the embodiments of the present application will be combined with Figure 3 and Figure 4 to introduce the operation process of the heat pump system. Among them, Figure 4 is the temperature-entropy diagram corresponding to the heat pump system operating in the optimal state. The curve W in the figure represents the saturation line. The high-temperature fluid at the outlet of the second compressor 12 will enter the first heat exchange member 21 for cooling and heat release, and then the fluid will enter the first heat exchange flow channel 231 for subcooling and temperature reduction, and then the fluid will enter the third heat exchange flow channel 41 for further temperature reduction treatment. Then a part of the fluid enters the ejector 90 as the high-pressure main stream, and the other part enters the second heat exchange flow channel 232 after throttling by the second throttling member 32, and plays the role of absorbing the heat of the fluid in the first heat exchange flow channel 231, and then enters the second compressor 12 to play the role of intermediate cooling and air supplement for the compression assembly 10.

[0090] For the fluid at the outlet of the ejector 90, it is in a two-phase state and enters the gas-liquid separator 70. Then the gaseous fluid will leave the gas-liquid separator 70 and enter the first compressor 11 for compression treatment. The liquid fluid will leave the gas-liquid separator 70, and a part of it enters the second heat exchange member 22 for evaporation and heat absorption, and then enters the ejector 90 as the low-pressure secondary flow for entrainment. And the other part of the liquid fluid enters the fourth heat exchange flow channel 42, absorbs the heat of the fluid in the third heat exchange flow channel 41 and becomes gaseous, and then converges with the fluid at the outlet of the ejector 90 and returns to the gas-liquid separator 70 together.

[0091] In summary, in the embodiments of the present application, by providing that the cooling member 40 includes two heat exchange channels, the fluid at the outlet of the third heat exchange member 23 is used to heat the excess liquid fluid in the gas-liquid separator 70, which can adjust the gas-liquid balance degree inside the gas-liquid separator 70, reduce the risk of excessive or insufficient liquid fluid inside the gas-liquid separator 70, and enable the heat pump system to operate in a better or even optimal state. At the same time, the temperature of the fluid at the first inlet end 311 can be further reduced, improving the overall performance of the heat pump system.

[0092] In some embodiments, as Figure 3 shown, the heat pump system further includes a second control member 62. The inlet of the fourth heat exchange channel 42 and the inlet of the second heat exchange member 22 are connected in parallel to the second outlet end 72 through the second control member 62. Among them, the second control member 62 is used to control the fluid ratio entering the fourth heat exchange channel 42 and the second heat exchange member 22.

[0093] The second control member 62 is used to control the diversion state of the liquid fluid leaving the gas-liquid separator 70. It can control the amount of fluid entering the fourth heat exchange channel 42 or the amount of fluid entering the second heat exchange member 22. Optionally, the second control member 62 includes a three-way valve with adjustable opening.

[0094] On this basis, the embodiments of the present application can achieve flow distribution adjustment through the second control member 62, so that the liquid fluid leaving the gas-liquid separator 70 enters the second heat exchange member 22 and the fourth heat exchange channel 42 in appropriate proportions respectively, thereby meeting the gas-liquid balance requirements inside the gas-liquid separator 70 and enabling the heat pump system to be in the optimal flow distribution state.

[0095] Specifically, if the mass flow rate of the high-pressure main flow of the ejector 90 is m p , the mass flow rate of the low-pressure secondary flow is m s , the mass flow rate of the fluid at the outlet of the ejector 90 is m b , and the liquid phase proportion of this fluid is x b , m b = m p + m s . On this basis, when m b * x b > m s , the liquid level in the gas-liquid separator 70 rises. To meet the gas-liquid balance in the gas-liquid separator 70, at this time, it is necessary to increase the opening of the second control member 62 connected to the fourth heat exchange channel 42; when m b * x b < m s , the liquid level in the gas-liquid separator 70 drops. To meet the gas-liquid balance in the gas-liquid separator 70, at this time, it is necessary to close the channel of the second control member 62 connected to the fourth heat exchange channel 42.

[0096] Regarding m p and m s For the calculation method, taking the fluid as carbon dioxide as an example, a theoretical model of a transcritical carbon dioxide ejector 90 with non-equilibrium phase change correlation can be adopted. In this theoretical model, m p can be obtained from the energy conservation equation from the first inlet end 311 to the nozzle throat of the ejector 90, and the relationship is as follows:

[0097]

[0098]

[0099]

[0100] In the above formula, the subscript represents the nozzle throat, the subscript P represents the first inlet end 311, Q NE represents the flow rate calculation error caused by correcting the thermodynamic equilibrium assumption / kJ*kg -1 , V t represents the flow velocity at the nozzle throat / m*s -1 , represents the nozzle isentropic coefficient, A t represents the nozzle throat area / m 2 , ρ t represents the nozzle throat density / kg*m -3 .

[0101] And m s can be obtained by iterative calculation of the working fluid state in the mixing section and the diffuser section, and the relationship is as follows:

[0102] m s =A sm ρ s V sm

[0103] V m (m p +m s )=η s , m (m p V m +m s V sm )

[0104]

[0105]

[0106] h B (m p +m s )=mp h p +m s h s

[0107] In the above formula, the subscript pm represents the state of the high-pressure main flow at the inlet of the equal-area mixing section, the subscript sm represents the state of the low-pressure secondary flow at the inlet of the equal-area mixing section, and η s，m represents the loss coefficient during the momentum exchange process between the high-pressure main flow and the low-pressure secondary flow in the ejector 90, and represents the isentropic coefficient of the diffuser section.

[0108] It should be noted that, in some embodiments, the heat pump system may further include a third control member 63. The outlet of the fourth heat exchange flow path 42 and the outlet of the ejector 90 are connected in parallel to the inlet of the gas-liquid separator 70 through the third control member 63. In other words, the fluid at the outlet of the fourth heat exchange flow path 42 and the fluid at the outlet of the ejector 90 converge at the third control member 63 and then enter the gas-liquid separator 70 together. Optionally, the third control member 63 includes a three-way valve.

[0109] In some embodiments, as Figure 3 shown, the heat pump system further includes a third throttling member 33. The inlet of the second heat exchange member 22 is connected to the second control member 62 through the third throttling member 33.

[0110] The third throttling member 33 is a functional component that can achieve a throttling effect. A part of the fluid leaving the gas-liquid separator 70 will first enter the third throttling member 33, and then leave the third throttling member 33 and enter the second heat exchange member 22. Optionally, the third throttling member 33 includes a throttle valve.

[0111] Taking the third throttling member 33 including a throttle valve as an example, in the embodiments of the present application, when the external environmental conditions change, for example, when the environmental temperature changes, the evaporation temperature of the fluid in the second heat exchange member 22 can be adjusted by adjusting the opening degree of the third throttling member 33, so that the operation process of the heat pump system can meet the actual heat exchange needs.

[0112] Further optionally, the heat pump system further includes a second throttling member 32, a second control member 62, and a third control member 63. When the environmental temperature changes, the opening degree of the third throttling member 33 can be adjusted first to meet the actual heat exchange needs of the heat pump system. Then, at least one of the second throttling member 32, the first control member 61, and the second control member 62 is adjusted comprehensively, so that the heat pump system can still operate in the best state when the environmental temperature changes, thereby meeting the operation needs of the heat pump system in a harsh low-temperature environment.

[0113] In some embodiments, as Figure 3As shown, the heat pump system further includes a first one-way member 64 disposed between the outlet of the second heat exchange flow path 232 and the inlet of the second compressor 12; and / or, the heat pump system further includes a second one-way member 65 and a third control member 63, the second one-way member 65 is disposed between the outlet of the fourth heat exchange flow path 42 and the third control member 63; and / or, the heat pump system further includes a third one-way member 66 and a third control member 63, the third one-way member 66 is disposed between the third control member 63 and the inlet of the gas-liquid separator 70.

[0114] The first one-way member 64, the second one-way member 65, and the third one-way member 66 are all fluid control devices that allow fluid to flow in only one direction and impede the reverse flow of fluid. Among them, the first one-way member 64 can allow more fluid to flow from the second heat exchange flow path 232 into the second compressor 12, the second one-way member 65 can allow more fluid to flow from the fourth heat exchange flow path 42 into the third control member 63, and the third one-way member 66 can allow more fluid to flow from the third control member 63 into the gas-liquid separator 70.

[0115] It should be noted that according to different actual needs, the heat pump system can be provided with only one or two of the first one-way member 64, the second one-way member 65, and the third one-way member 66, or the heat pump system can also be provided with the above three one-way members at the same time. Optionally, the heat pump system includes the first one-way member 64, the second one-way member 65, and the third one-way member 66 at the same time to further improve the reliability of the fluid flow direction inside the heat pump system. Further optionally, the first one-way member 64, the second one-way member 65, and the third one-way member 66 all include check valves.

[0116] In the embodiments of the present application, considering that during the operation of the heat pump system, the required fluid flow direction of the heat pump system always remains unchanged, one or more one-way members can be selectively provided in the heat pump system to improve the reliability of the one-way flow of the fluid in the heat pump system.

[0117] In some embodiments, as Figure 3 shown, the heat pump system further includes a driving member 80 disposed between the second outlet end 72 and the fourth heat exchange flow path 42.

[0118] The driving member 80 is a mechanical component for transporting fluid. The driving member 80 can provide power for the flow of the fluid to meet the need for the fluid to circulate in the heat pump system, and the fluid passing through the driving member 80 will also be pressurized under the action of the driving member 80. Optionally, the driving member 80 includes a pressure pump.

[0119] In an embodiment of the present application, by arranging a driving member 80 in the heat pump system, the fluid in the heat pump system can circulate better, improving the operating reliability of the heat pump system. On this basis, by arranging the driving member 80 at the second outlet end 72 and the fourth heat exchange flow path 42, the fluid passing through the fourth heat exchange flow path 42 can be pressurized by means of the driving member 80, thereby increasing the fluid pressure reaching the third control member 63 so that it can be the same as the fluid pressure at the outlet of the ejector 90, and further improving the mixing effect of the two.

[0120] According to some alternative embodiments of the present application, as Figure 3 shown, the heat pump system includes a compression assembly 10, a first heat exchanger 21, a first throttling member 31, and a second heat exchanger 22 connected in sequence. The compression assembly 10 includes a first compressor 11 and a second compressor 12 connected in communication. The outlet of the first compressor 11 is connected to the inlet of the second compressor 12. The heat pump system further includes a third heat exchanger 23, a cooling member 40, a second throttling member 32, a first control member 61, a gas-liquid separator 70, a second control member 62, a third control member 63, a fourth control member, a third throttling member 33, a first one-way member 64, a second one-way member 65, a third one-way member 66, and a driving member 80.

[0121] The third heat exchanger 23 includes a first heat exchange flow path 231 and a second heat exchange flow path 232 that implement heat exchange functions. The inlet of the first heat exchange flow path 231 is connected to the outlet of the first heat exchanger 21, and the inlet of the cooling member 40 is connected to the outlet of the first heat exchange flow path 231. Among them, the pipeline structure in the heat pump system includes a first pipeline 51 and a second pipeline 52 connected in parallel to the outlet of the cooling member 40. The first pipeline 51 is connected to the inlet of the first throttling member 31. Both ends of the second heat exchange flow path 232 are respectively connected to the second pipeline 52 and the inlet of the second compressor 12, and the second throttling member 32 is arranged on the second pipeline 52.

[0122] The first throttling member 31 includes an ejector 90. The inlet of the ejector 90 includes a first inlet end 311 and a second inlet end 312. The first inlet end 311 is connected to the first pipeline 51, the second inlet end 312 is connected to the outlet of the second heat exchanger 22, the outlet of the ejector 90 is connected to the inlet of the gas-liquid separator 70, and the outlet of the gas-liquid separator 70 includes a first outlet end 71 and a second outlet end 72. The first outlet end 71 is connected to the inlet of the first compressor 11, and the second outlet end 72 is connected to the inlet of the second heat exchanger 22.

[0123] The cooling member 40 includes a third heat exchange flow path 41 and a fourth heat exchange flow path 42 that implement a heat exchange function. The inlet of the third heat exchange flow path 41 is connected to the outlet of the first heat exchange flow path 231. The first pipeline 51 and the second pipeline 52 are connected in parallel to the outlet of the third heat exchange flow path 41. Among them, the outlet of the fourth heat exchange flow path 42 and the inlet of the second heat exchange member 22 are connected in parallel to the second outlet end 72, and the outlet of the fourth heat exchange flow path 42 and the outlet of the ejector 90 are connected in parallel to the inlet of the gas-liquid separator 70.

[0124] The inlet of the fourth heat exchange flow path 42 and the inlet of the second heat exchange member 22 are connected in parallel to the second outlet end 72 through a second control member 62. Among them, the second control member 62 is used to control the fluid ratio entering the fourth heat exchange flow path 42 and the second heat exchange member 22. The outlet of the fourth heat exchange flow path 42 and the outlet of the ejector 90 are connected in parallel to the inlet of the gas-liquid separator 70 through a third control member 63. The outlet of the first compressor 11 and the outlet of the fourth heat exchange flow path 42 are connected in parallel to the inlet of the second compressor 12 through a fourth control member.

[0125] A first one-way member 64 is arranged between the outlet of the second heat exchange flow path 232 and the inlet of the second compressor 12. A second one-way member 65 is arranged between the outlet of the fourth heat exchange flow path 42 and the third control member 63. A third one-way member 66 is arranged between the third control member 63 and the inlet of the gas-liquid separator 70. A driving member 80 is arranged between the second outlet end 72 and the fourth heat exchange flow path 42.

[0126] In a second aspect, please refer to Figure 3 and Figure 5 , an embodiment of the present application provides a control method for a heat pump system, which is used to control the heat pump system in any of the foregoing embodiments. The heat pump system further includes a first control member 61. The first pipeline 51 and the second pipeline 52 are connected in parallel to the outlet of the first heat exchange flow path 231 through the first control member 61. The control method includes:

[0127] S100: Adjust the first control member.

[0128] In this step, in addition to realizing the parallel connection of the first pipeline 51 and the second pipeline 52 relative to the outlet of the cooling member 40 to meet the basic operation requirements of the heat pump system, the first control member 61 can also play a role in adjusting the flow distribution. On this basis, the first control member 61 can be used to change the fluid flow rates in the first pipeline 51 and the second pipeline 52, so as to flexibly adjust the flow distribution of the first pipeline 51 and the second pipeline 52, so that the fluid in the heat pump system can be in an optimal flow distribution state.

[0129] S110: Adjust the opening degree of the second throttling member.

[0130] In step S110, by adjusting the opening degree of the second throttling member 32, the evaporation temperature of the fluid in the second heat exchange channel 232 is adjusted, so that the heat pump system can be in a first operating state. The "first operating state" mentioned here refers to the optimal state of the heat pump system, that is, under the current ambient working conditions, the ideal operating state when the coefficient of performance of the heat pump system reaches the maximum value.

[0131] Furthermore, whether the heat pump system is in the first operating state needs to be specifically determined according to the actual working conditions corresponding to the operation of the heat pump system and the numerical value displayed by the flowmeter at a specific point in the heat pump system. It can be directly measured through experiments or can also be calculated by means of simulation. The embodiments of the present application do not limit this. Exemplarily, in the first operating state, the fluid at the outlet of the second heat exchange channel 232 is in a saturated gaseous state.

[0132] It should be noted that the "saturated gaseous state" mentioned here means that the fluid state at the outlet of the second heat exchange channel 232 can be located at or close to the saturation line in the temperature-entropy diagram. It does not require the fluid state to be precisely located on the saturation line, but allows the fluid to have a certain degree of superheat within a certain range.

[0133] In summary, in the embodiments of the present application, with the help of the first control member 61, the flow rate distribution of the first pipeline 51 and the second pipeline 52 can be flexibly adjusted, so that the fluid in the heat pump system can be in the optimal flow rate distribution state, and by adjusting the opening degree of the second throttling member 32, the evaporation temperature of the fluid in the second heat exchange channel 232 can be adjusted, so that the heat pump system operates in the optimal state and the overall performance of the heat pump system is improved.

[0134] In some embodiments, the first throttling member 31 includes an ejector 90. The inlet of the ejector 90 includes a first inlet end 311 and a second inlet end 312. The first inlet end 311 is communicated with the first pipeline 51, and the second inlet end 312 is communicated with the outlet of the second heat exchange member 22. The heat pump system further includes a gas-liquid separator 70. The outlet of the ejector 90 is communicated with the inlet of the gas-liquid separator 70. The outlet of the gas-liquid separator 70 includes a first outlet end 71 and a second outlet end 72. The first outlet end 71 is communicated with the inlet of the first compressor 11, and the second outlet end 72 is communicated with the inlet of the second heat exchange member 22.

[0135] The cooling member 40 includes a third heat exchange flow path 41 and a fourth heat exchange flow path 42 that achieve the heat exchange function. The inlet of the third heat exchange flow path 41 is connected to the outlet of the first heat exchange flow path 231, and the first pipeline 51 and the second pipeline 52 are connected in parallel to the outlet of the third heat exchange flow path 41. The inlet of the fourth heat exchange flow path 42 and the inlet of the second heat exchange member 22 are connected in parallel to the second outlet end 72 through the second control member 62, and the outlet of the fourth heat exchange flow path 42 and the outlet of the ejector 90 are connected in parallel to the inlet of the gas-liquid separator 70. Among them, the second control member 62 is used to adjust the fluid ratio entering the fourth heat exchange flow path 42 and the second heat exchange member 22.

[0136] On this basis, please refer to Figure 3 and Figure 6 , after step S110, it further includes:

[0137] S120: Determine whether the liquid level in the gas-liquid separator changes.

[0138] In step S120, it is possible to determine whether the liquid level in the gas-liquid separator 70 changes by setting a liquid level sensor in the gas-liquid separator 70.

[0139] S130: When the liquid level in the gas-liquid separator changes, adjust the second control member.

[0140] In step S130, when the liquid level in the liquid level separator changes, it indicates that the gas-liquid balance inside the gas-liquid separator 70 is broken. At this time, the flow rate distribution can be adjusted through the second control member 62 to change the fluid flow rates entering the inlet of the fourth heat exchange flow path 42 and the inlet of the second heat exchange flow path 232, so that the liquid fluid leaving the gas-liquid separator 70 enters the second heat exchange member 22 and the fourth heat exchange flow path 42 in appropriate proportions, thereby changing the liquid level state in the liquid level separator and restoring it to the gas-liquid balance state to meet the needs of the heat pump system being in the optimal flow rate distribution state.

[0141] In some embodiments, please refer to Figure 3 and Figure 7 , the first throttling member 31 includes an ejector 90. The inlet of the ejector 90 includes a first inlet end 311 and a second inlet end 312. The first inlet end 311 is connected to the first pipeline 51, and the second inlet end 312 is connected to the outlet of the second heat exchange member 22. The heat pump system further includes a gas-liquid separator 70. The outlet of the ejector 90 is connected to the inlet of the gas-liquid separator 70. The outlet of the gas-liquid separator 70 includes a first outlet end 71 and a second outlet end 72. The first outlet end 71 is connected to the inlet of the first compressor 11, and the second outlet end 72 is connected to the inlet of the second heat exchange member 22.

[0142] The cooling member 40 includes a third heat exchange flow path 41 and a fourth heat exchange flow path 42 that achieve the heat exchange function. The inlet of the third heat exchange flow path 41 is connected to the outlet of the first heat exchange flow path 231, and the first pipeline 51 and the second pipeline 52 are connected in parallel to the outlet of the third heat exchange flow path 41. The inlet of the fourth heat exchange flow path 42 and the inlet of the second heat exchange member 22 are connected in parallel to the second outlet end 72, and the outlet of the fourth heat exchange flow path 42 and the outlet of the ejector 90 are connected in parallel to the inlet of the gas-liquid separator 70. Among them, the heat pump system further includes a driving member 80, and the driving member 80 is arranged between the second outlet end 72 and the fourth heat exchange flow path 42.

[0143] On this basis, before the steps, it further includes:

[0144] S140: Control the operation of the first compressor and the second compressor.

[0145] In step S140, before the formal operation of the heat pump system, all the control switches in the heat pump system can be first turned on and adjusted, such as the first control member 61, the second control member 62, the third control member 63, the first throttling member 31, the second throttling member 32, the third throttling member 33, the first one-way member 64, the second one-way member 65, and the third one-way member 66, etc. Then start the first compressor 11 to preliminarily compress the low-temperature and low-pressure fluid (such as carbon dioxide), and then turn on the second compressor 12 to further compress the fluid to a better or even optimal exhaust pressure of the heat pump system.

[0146] S150: Control the operation of the driving member.

[0147] In step S150, the driving member 80 can provide power for the flow of the fluid and have a pressurizing effect on the fluid. On this basis, starting the driving member 80 can not only enable the fluid in the heat pump system to circulate better and improve the operation reliability of the heat pump system, but also pressurize the fluid entering the fourth heat exchange flow path 42, so that the fluid at the outlet of the fourth heat exchange flow path 42 and the fluid at the outlet of the ejector 90 have the same pressure, thereby improving the mixing effect of the two.

[0148] In some embodiments, please refer to Figure 3 and Figure 8 , the first throttling member 31 includes an ejector 90. The inlet of the ejector 90 includes a first inlet end 311 and a second inlet end 312. The first inlet end 311 is connected to the first pipeline 51, and the second inlet end 312 is connected to the outlet of the second heat exchange member 22. The heat pump system further includes a gas-liquid separator 70. The outlet of the ejector 90 is connected to the inlet of the gas-liquid separator 70. The outlet of the gas-liquid separator 70 includes a first outlet end 71 and a second outlet end 72. The first outlet end 71 is connected to the inlet of the first compressor 11, and the second outlet end 72 is connected to the inlet of the second heat exchange member 22.

[0149] The cooling member 40 includes a third heat exchange flow path 41 and a fourth heat exchange flow path 42 that implement a heat exchange function. The inlet of the third heat exchange flow path 41 communicates with the outlet of the first heat exchange flow path 231, and the first pipeline 51 and the second pipeline 52 are connected in parallel to the outlet of the third heat exchange flow path 41. The inlet of the fourth heat exchange flow path 42 and the inlet of the second heat exchange member 22 are connected in parallel to the second outlet end 72 through the second control member 62, and the outlet of the fourth heat exchange flow path 42 and the outlet of the ejector 90 are connected in parallel to the inlet of the gas-liquid separator 70. Among them, the second control member 62 is used to adjust the fluid ratio entering the fourth heat exchange flow path 42 and the second heat exchange member 22.

[0150] On this basis, after step S110, it further includes:

[0151] S160: Determine whether the ambient temperature for heat exchange with the second heat exchange member changes.

[0152] In step S160, considering that the second heat exchange member 22 needs to exchange heat with the external ambient air, and the ambient temperature may not remain fixed, in order to improve the overall performance of the heat pump system under different ambient temperature conditions, it is necessary to detect the external ambient temperature and adjust the operating state of specific functional components in the heat pump system in a timely manner when the external ambient temperature changes.

[0153] S170: When the ambient temperature changes, adjust the opening degree of the third throttling member 33.

[0154] In step S170, when the ambient temperature changes, the evaporation temperature of the fluid in the second heat exchange member 22 can be changed by adjusting the opening degree of the third throttling member 33, so that the operation process of the heat pump system can meet the actual heat exchange needs.

[0155] S180: Adjust at least one of the first control member 61, the second control member 62, and the second throttling member 32.

[0156] In step S180, by comprehensively adjusting at least one of the second throttling member 32, the first control member 61, and the second control member 62, the heat pump system can still be in the first operating state when the ambient temperature changes, so as to meet the operating requirements of the heat pump system in a harsh low-temperature environment.

[0157] Further, in combination with Figure 3 the heat pump system shown, according to some embodiments of the present application, the control method of the heat pump system may sequentially include three stage states: a startup stage, an operation stage, and a variable working condition stage.

[0158] In the startup phase of the heat pump system, first turn on and adjust all the control switches in the heat pump system, such as the first control member 61, the second control member 62, the third control member 63, the first throttling member 31, the second throttling member 32, the third throttling member 33, the first check member 64, the second check member 65, and the third check member 66, etc. Then start the first compressor 11 to preliminarily compress the low-temperature and low-pressure fluid (such as carbon dioxide), and then turn on the second compressor 12 to further compress the fluid to a better or even optimal exhaust pressure of the heat pump system. Finally, start the driving member 80 so that the fluid at the outlet of the fourth heat exchange channel 42 has the same pressure as the fluid at the outlet of the ejector 90, thereby improving the mixing effect of the two.

[0159] In the operation phase of the heat pump system, first, according to actual needs, adjust the first control member 61 to adjust the flow rate distribution between the first pipeline 51 and the second pipeline 52. At this time, part of the fluid is throttled and then enters the third heat exchange member 23, and the other part enters the ejector 90 as the high-pressure main flow, so that the fluid in the heat pump system can be in the optimal flow rate distribution state. Then adjust the opening degree of the second throttling member 32 to adjust the evaporation temperature of the fluid in the second heat exchange channel 232, so that the heat pump system can be in the first operating state. Finally, during the operation of the heat pump system, judge the liquid level change in the gas-liquid separator 70 in real time or at intervals. When the liquid level in the liquid level separator changes, adjust the second control member 62 to change the flow rate of the fluid entering the inlet of the fourth heat exchange channel 42 and the inlet of the second heat exchange channel 232, so that the liquid fluid leaving the gas-liquid separator 70 enters the second heat exchange member 22 and the fourth heat exchange channel 42 in appropriate proportions, thereby changing the liquid level state in the liquid level separator and restoring it to the gas-liquid equilibrium state to meet the needs of the heat pump system in the optimal flow rate distribution state.

[0160] In the off-design condition phase of the heat pump system, judge in real time or at intervals whether the ambient temperature for heat exchange with the second heat exchange member 22 changes. When the ambient temperature changes, adjust the opening degree of the third throttling member 33 to change the evaporation temperature of the fluid in the second heat exchange member 22, so that the operation process of the heat pump system can meet the actual heat exchange needs. Then comprehensively adjust at least one of the second throttling member 32, the first control member 61, and the second control member 62, so that the heat pump system can still be in the first operating state when the ambient temperature changes, thereby meeting the operation needs of the heat pump system in a harsh low-temperature environment.

[0161] Although the embodiments disclosed in the present application are as above, the content described above is only an embodiment adopted for the convenience of understanding the present application and is not intended to limit the present invention. Any person skilled in the art within the technical field to which the present application pertains may make any modifications and changes in the form of implementation and details without departing from the spirit and scope disclosed in the present application. However, the protection scope of the present application shall still be subject to the scope defined by the appended claims.

[0162] As described above, this is only a specific implementation manner of the present application. Those skilled in the art can clearly understand that for the sake of convenience and brevity of description, the replacement of other connection manners described above and the like can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein. It should be understood that the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present application can easily think of various equivalent modifications or replacements, and these modifications or replacements should all be covered within the protection scope of the present application.

Claims

1. A heat pump system, characterized in that: The invention comprises a compression assembly, a first heat exchange element, a first throttling element and a second heat exchange element which are sequentially connected and arranged, wherein the compression assembly comprises a first compressor and a second compressor which are connected and arranged, and the outlet of the first compressor is connected to the inlet of the second compressor; The heat pump system further comprises: A third heat exchange element, comprising a first heat exchange channel and a second heat exchange channel for realizing a heat exchange function, wherein the inlet of the first heat exchange channel is connected to the outlet of the first heat exchange element, and the outlet of the second heat exchange channel is connected to the inlet of the second compressor; a second throttling member, wherein an outlet of the second throttling member is connected to an inlet of the second heat exchange flow channel; Among them, the pipeline structure in the heat pump system includes a first pipeline and a second pipeline connected in parallel to the outlet of the first heat exchange channel, the first pipeline is connected to the inlet of the first throttling device, and the second throttling device is connected to the second heat exchange channel through the second pipeline.

2. The heat pump system according to claim 1, characterized in that: The heat pump system further includes a first control component, and the first pipeline and the second pipeline are connected in parallel to the outlet of the first heat exchange flow channel through the first control component; The first control component is used to adjust the flow rate of the fluid entering the first pipeline and the second pipeline.

3. The heat pump system according to claim 1, characterized in that: The first throttling element includes an ejector, the inlet of the ejector includes a first inlet end and a second inlet end, the first inlet end is connected to the first pipeline, and the second inlet end is connected to the outlet of the second heat exchange element; The heat pump system also includes a gas-liquid separator, the outlet of the ejector is connected to the inlet of the gas-liquid separator, the outlet of the gas-liquid separator includes a first outlet end and a second outlet end, the first outlet end is connected to the inlet of the first compressor, and the second outlet end is connected to the inlet of the second heat exchange element.

4. The heat pump system according to claim 3, characterized in that: The cooling element further comprises a third heat exchange channel and a fourth heat exchange channel for realizing a heat exchange function, the inlet of the third heat exchange channel is connected to the outlet of the first heat exchange channel, and the first pipeline and the second pipeline are connected in parallel to the outlet of the third heat exchange channel; The inlet of the fourth heat exchange channel and the inlet of the second heat exchange element are connected in parallel to the second outlet end, and the outlet of the fourth heat exchange channel and the outlet of the ejector are connected in parallel to the inlet of the gas-liquid separator.

5. The heat pump system according to claim 4, characterized in that: The heat pump system further includes a second control element, and the inlet of the fourth heat exchange flow channel and the inlet of the second heat exchange element are connected in parallel to the second outlet end through the second control element; Wherein, the second control element is used to adjust the ratio of the fluid entering the fourth heat exchange channel and the second heat exchange element.

6. The heat pump system according to claim 5, characterized in that: The heat pump system further includes a third throttling element, and the inlet of the second heat exchange element is connected to the second control element through the third throttling element.

7. The heat pump system according to claim 5, characterized in that: The heat pump system further includes a first one-way member, which is arranged between the outlet of the second heat exchange channel and the inlet of the second compressor; and / or, The heat pump system further comprises a third control member and a second one-way member, the outlet of the fourth heat exchange channel and the outlet of the ejector are connected in parallel to the inlet of the gas-liquid separator through the third control member, and the second one-way member is arranged between the outlet of the fourth heat exchange channel and the inlet of the gas-liquid separator; and / or, The heat pump system also includes a third control component and a third one-way component. The outlet of the fourth heat exchange channel and the outlet of the ejector are connected in parallel to the inlet of the gas-liquid separator through the third control component. The third one-way component is arranged between the third control component and the inlet of the gas-liquid separator.

8. The heat pump system according to claim 5, characterized in that: It also includes a driving member, which is arranged between the second outlet end and the fourth heat exchange channel.

9. A control method for a heat pump system, characterized in that: Used to control the heat pump system according to any one of claims 1 to 8, the heat pump system further comprising a first control component, the first pipeline and the second pipeline are connected in parallel to the outlet of the first heat exchange flow channel through the first control component; the control method comprises: adjusting the first control element to change the fluid flow in the first pipeline and the second pipeline; The opening of the second throttling member is adjusted so that the heat pump system is in a first operating state. In the first operating state, the fluid at the outlet of the second heat exchange flow channel is in a saturated gas state.

10. The control method according to claim 9, characterized in that: The heat pump system comprises the heat pump system according to claim 5, and the first control element and the second throttling element; after adjusting the opening of the second throttling element, the control method further comprises: Determining whether the liquid level in the gas-liquid separator changes; When the liquid level of the gas-liquid separator changes, the second control element is adjusted to change the fluid flow rate entering the inlet of the fourth heat exchange channel and the fluid flow rate entering the inlet of the second heat exchange element.

11. The control method according to claim 9, characterized in that: The heat pump system comprises the heat pump system according to claim 8, and the first control element and the second throttling element. Before controlling the first control element, the control method further comprises: controlling the operation of the first compressor and the second compressor; The driving member is controlled to operate so that the fluid at the outlet of the fourth heat exchange flow channel and the fluid at the outlet of the ejector have the same pressure.

12. The control method according to claim 9, characterized in that: The heat pump system comprises the heat pump system according to claim 5, and the first control element and the second throttling element; After adjusting the opening of the second throttling member, the control method further includes: determining whether the temperature of the environment in which the second heat exchange element performs heat exchange has changed; When the ambient temperature changes, adjusting the opening of the third throttling element to change the evaporation temperature of the fluid in the second heat exchange element; At least one of the first control element, the second control element, and the second throttling element is adjusted to put the heat pump system in the first operating state.

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