A heat pump air conditioning system

Abstract

This application relates to the technical field of heat exchange and discloses a heat pump air conditioning system. The heat pump air conditioning system includes a compressor, a four-way valve, an indoor heat exchanger, a phase change heat storage module, an outdoor heat exchanger, a first throttling pipe assembly, a second throttling pipe assembly, a first pipe assembly, a second pipe assembly, a third pipe assembly, and a fourth pipe assembly. The first port of the four-way valve is connected to the compressor. The indoor heat exchanger is connected to the second port of the four-way valve. The phase change heat storage module is connected to the indoor heat exchanger through the first throttling pipe assembly. The phase change heat storage module is connected to the compressor through the first pipe assembly. The outdoor heat exchanger is connected to the phase change heat storage module through the second throttling pipe assembly. The first throttling pipe assembly and the second throttling pipe assembly are connected through the second pipe assembly. The outdoor heat exchanger is connected to the fourth port of the four-way valve. The heat pump air conditioning system provided by this application has high operational reliability.

Description

Technical Field

[0001] This application relates to the field of heat exchange technology, and more particularly to a heat pump air conditioning system. Background Technology

[0002] Heat pump air conditioning systems do not "generate heat," but rather use a compressor to drive a refrigerant cycle, absorbing heat from a low-temperature environment and transferring it to a high-temperature area. The core of their operation is "heat transport" rather than "energy conversion."

[0003] In related technologies, heat pump air conditioning systems include compressors, four-way valves, indoor heat exchangers, outdoor heat exchangers, and throttling devices.

[0004] However, its operational reliability is low. Summary of the Invention

[0005] This application provides a heat pump air conditioning system with high operational reliability.

[0006] This application provides a heat pump air conditioning system, including:

[0007] compressor;

[0008] A four-way valve, the first port of which is connected to the compressor;

[0009] The indoor heat exchanger is connected to the second port of the four-way valve;

[0010] The phase change heat storage module is connected to the indoor heat exchanger through the first throttling tube group; the phase change heat storage module is connected to the compressor through the first tube group.

[0011] The outdoor heat exchanger is connected to the phase change heat storage module through the second throttling tube group, and the first throttling tube group and the second throttling tube group are connected through the second tube group. One of the first throttling tube group and the second throttling tube group is configured to throttle the refrigerant. The outdoor heat exchanger is connected to the fourth port of the four-way valve.

[0012] The third pipe assembly is configured to control whether the third port of the four-way valve is connected to or not connected to the compressor, and to control whether the third port of the four-way valve is connected to or not connected to the phase change heat storage module.

[0013] The fourth tube group is configured to control whether the second port is connected to or not connected to the phase change thermal storage module.

[0014] The heat pump air conditioning system provided in this application includes a compressor, a four-way valve, an indoor heat exchanger, a phase change heat storage module, an outdoor heat exchanger, a first throttling pipe assembly, a second throttling pipe assembly, a first pipe assembly, a second pipe assembly, a third pipe assembly, and a fourth pipe assembly. The first port of the four-way valve is connected to the compressor. The indoor heat exchanger is connected to the second port of the four-way valve. The phase change heat storage module is connected to the indoor heat exchanger via the first throttling pipe assembly. The phase change heat storage module is connected to the compressor via the first pipe assembly. The outdoor heat exchanger is connected to the phase change heat storage module via the second throttling pipe assembly. The first and second throttling pipe assemblies are connected via the second pipe assembly, and one of the first and second throttling pipe assemblies is configured to throttle the refrigerant. The outdoor heat exchanger is connected to the fourth port of the four-way valve. The third pipe assembly is configured to control whether the third port of the four-way valve is connected to or not connected to the compressor, and to control whether the third port of the four-way valve is connected to or not connected to the phase change heat storage module. The fourth pipe assembly is configured to control whether the second port is connected to or not connected to the phase change heat storage module. In this way, by controlling the refrigerant flow direction through the four-way valve, the first throttling pipe assembly, the second throttling pipe assembly, the third pipe assembly, and the fourth pipe assembly, heating regenerative cycle, cooling regenerative cycle, heating superheat cycle, and phase change heat storage defrost cycle can be realized. In the heating and cooling regenerative cycles, the heat released by the phase change heat storage module increases the compressor's suction superheat, improving operational reliability. The heating superheat cycle increases the refrigerant superheat, increases the compressor's suction superheat, improves reliability, increases overall heating capacity, and improves system heating efficiency. The phase change heat storage defrost cycle utilizes the heat released by the phase change heat storage module to increase the compressor's suction superheat, improving operational reliability.

[0015] In some embodiments, the first throttling tube assembly includes:

[0016] The first throttling device is connected to the indoor heat exchanger;

[0017] The first control valve is connected to the indoor heat exchanger. The first control valve is connected in parallel with the first throttle. The first control valve is configured to control the short circuit of the first throttle or the flow of refrigerant.

[0018] The first three-way valve is connected in series with the first throttle and the first control valve, and is connected to the first throttle, the first control valve, the phase change heat storage module, and the second pipe group.

[0019] In this way, by setting up a first throttling device and a first control valve, the first throttling pipe assembly can determine whether the refrigerant flows through the first throttling device or the first control valve, thus meeting the different throttling requirements of the heat pump air conditioning system. By setting up a first three-way valve, the connection or disconnection in three different directions can be controlled. Compared with a two-way valve, this helps to simplify the number of components in the heat pump air conditioning system, reduce the overall footprint, and lower costs.

[0020] In some embodiments, the second throttling tube assembly includes:

[0021] The second throttle has its first end connected to the second tube group and the phase change heat storage module respectively, and its second end connected to the outdoor heat exchanger.

[0022] The second control valve is connected in parallel with the second throttle. The first end of the second control valve is connected to the second pipe group and the phase change heat storage module, respectively, and the second end of the second control valve is connected to the outdoor heat exchanger. The second control valve is configured to control the short circuit or flow of refrigerant in the second throttle.

[0023] In this way, by setting a second throttling device and a second control valve, the second throttling pipe assembly can determine whether the refrigerant flows through the second throttling device or the second control valve, thereby meeting the requirements of different throttling positions of the heat pump air conditioning system.

[0024] In some embodiments, the third tube assembly includes:

[0025] The second three-way valve is connected to the third port, the phase change heat storage module, and the compressor, respectively.

[0026] In this way, by setting a second three-way valve, the connection or disconnection in three different directions can be controlled. Compared with a two-way valve, this helps to simplify the number of components in the heat pump air conditioning system, reduce the overall footprint, and lower costs.

[0027] In some embodiments, the fourth tube group includes:

[0028] The third control valve is connected to the second port and the phase change heat storage module, respectively.

[0029] In this way, the third control valve can control whether the second port and the phase change thermal storage module are connected or not.

[0030] In some embodiments, the end of the first pipe group away from the phase change heat storage module is connected to the connecting pipe between the second three-way valve and the compressor.

[0031] In this way, the first and third pipe groups can share some connecting pipes, which helps to reduce the overall footprint and lower costs.

[0032] In some embodiments, when the heat pump air conditioning system is operating in defrost mode, the first throttling tube group is configured to throttle the refrigerant, and the second throttling tube group is configured to allow the refrigerant to flow.

[0033] The refrigerant discharged from the compressor returns to the compressor sequentially through a four-way valve, indoor heat exchanger, first throttling tube group, phase change heat storage module, second throttling tube group, outdoor heat exchanger, four-way valve, and third tube group;

[0034] Alternatively, when the heat pump air conditioning system is in defrost mode, the first throttling tube group is configured to not circulate refrigerant, and the second throttling tube group is configured to throttle refrigerant.

[0035] The refrigerant discharged from the compressor returns to the compressor sequentially through a four-way valve, an outdoor heat exchanger, a second throttling tube assembly, a phase change heat storage module, a fourth tube assembly, another four-way valve, and a third tube assembly.

[0036] In this way, when the heat pump air conditioning system can operate in defrost mode, it can run either uninterrupted heating cycle or phase change heat storage defrost cycle as needed.

[0037] In some embodiments, when the heat pump air conditioning system is operating in heating mode, the first throttling tube group is configured to allow refrigerant to flow, and the second throttling tube group is configured to allow refrigerant to throttle.

[0038] The refrigerant discharged from the compressor passes sequentially through a four-way valve, indoor heat exchanger, first throttling tube group, second tube group, second throttling tube group, outdoor heat exchanger, four-way valve, third tube group, phase change heat storage module, and first tube group back to the compressor.

[0039] Alternatively, when the heat pump air conditioning system is operating in heating mode, the first throttling tube group is configured to allow refrigerant to flow, and the second throttling tube group is configured to allow refrigerant to throttle.

[0040] The refrigerant discharged from the compressor passes sequentially through a four-way valve, indoor heat exchanger, first throttling tube group, phase change heat storage module, second throttling tube group, outdoor heat exchanger, four-way valve, third tube group, phase change heat storage module, and first tube group back to the compressor.

[0041] Alternatively, when the heat pump air conditioning system is operating in heating mode, the first throttling tube group is configured to allow refrigerant to flow, and the second throttling tube group is configured to allow refrigerant to throttle.

[0042] The refrigerant discharged from the compressor returns to the compressor sequentially through a four-way valve, indoor heat exchanger, first throttling pipe assembly, second pipe assembly, second throttling pipe assembly, outdoor heat exchanger, four-way valve, and third pipe assembly.

[0043] In this way, when the heat pump air conditioning system is in heating mode, it can run a superheating cycle, a regenerative cycle, or a normal heating cycle as needed.

[0044] In some embodiments, when the heat pump air conditioning system is operating in cooling mode, the first throttling tube group is configured to throttle the refrigerant, and the second throttling tube group is configured to allow the refrigerant to flow.

[0045] The refrigerant discharged from the compressor returns to the compressor sequentially through a four-way valve, outdoor heat exchanger, second throttling tube group, phase change heat storage module, first throttling tube group, indoor heat exchanger, four-way valve, and third tube group;

[0046] Alternatively, when the heat pump air conditioning system is operating in cooling mode, the first throttling tube group is configured to throttle the refrigerant, and the second throttling tube group is configured to allow the refrigerant to flow.

[0047] The refrigerant discharged from the compressor passes sequentially through a four-way valve, outdoor heat exchanger, second throttling tube assembly, phase change heat storage module, first throttling tube assembly, indoor heat exchanger, four-way valve and third tube assembly, phase change heat storage module, and first tube assembly back to the compressor;

[0048] Alternatively, when the heat pump air conditioning system is operating in cooling mode, the first throttling tube group is configured to throttle the refrigerant, and the second throttling tube group is configured to allow the refrigerant to flow.

[0049] The refrigerant discharged from the compressor returns to the compressor sequentially through the four-way valve, outdoor heat exchanger, second throttling pipe group, second pipe group, first throttling pipe group, indoor heat exchanger, four-way valve, and third pipe group.

[0050] In this way, when the heat pump air conditioning system can operate in cooling mode, it can run a cooling subcooling cycle, a cooling heat recovery cycle, or a normal cooling cycle as needed.

[0051] In some embodiments, when the heat pump air conditioning system operates in phase change heat storage mode, the first throttling tube group is configured to not circulate refrigerant, and the second throttling tube group is configured to throttle refrigerant.

[0052] The refrigerant discharged from the compressor returns to the compressor sequentially through the four-way valve, the fourth pipe group, the phase change heat storage module, the second throttling pipe group, the outdoor heat exchanger, the four-way valve, and the third pipe group.

[0053] In this way, heat storage can be achieved by phase change heat storage modules. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of the structure of a heat pump air conditioning system provided in an embodiment of this application;

[0055] Figure 2 A schematic diagram of the state of a heat pump air conditioning system operating in an uninterrupted heating cycle, provided in an embodiment of this application;

[0056] Figure 3 A schematic diagram of the state of a heat pump air conditioning system operating in phase change heat storage defrosting cycle, provided in an embodiment of this application;

[0057] Figure 4 A schematic diagram of the state of a heat pump air conditioning system during heating and superheating cycle provided in an embodiment of this application;

[0058] Figure 5 A schematic diagram of the state of a heat pump air conditioning system operating in a heating and regeneration cycle, provided in an embodiment of this application;

[0059] Figure 6A schematic diagram of the state of a heat pump air conditioning system during normal heating cycle operation, provided in an embodiment of this application;

[0060] Figure 7 This is a schematic diagram of the state of a heat pump air conditioning system operating in a cooling subcooling cycle, provided in an embodiment of this application.

[0061] Figure 8 A schematic diagram of the state of a heat pump air conditioning system operating in a cooling and heating cycle, provided in an embodiment of this application;

[0062] Figure 9 A schematic diagram of the state of a heat pump air conditioning system during normal refrigeration cycle operation, provided in an embodiment of this application;

[0063] Figure 10 This is a schematic diagram of the state of a heat pump air conditioning system operating in phase change heat storage cycle, as provided in an embodiment of this application.

[0064] Explanation of reference numerals in the attached figures:

[0065] 100 - Compressor;

[0066] 200-Four-way valve;

[0067] 300 - Indoor heat exchanger;

[0068] 400-Phase Change Thermal Storage Module;

[0069] 500 - First throttling tube assembly; 510 - First throttling device; 520 - First control valve; 530 - First three-way valve;

[0070] 600 - First Pipe Group;

[0071] 700 - Outdoor heat exchanger;

[0072] 800 - Second throttling tube assembly; 810 - Second throttling device; 820 - Second control valve;

[0073] 900 - Third pipe assembly; 910 - Second three-way valve;

[0074] 1000 - Fourth pipe assembly; 1010 - Third control valve;

[0075] 1100 - Second pipe group. Detailed Implementation

[0076] To make the objectives and implementation methods of this application clearer, the exemplary implementation methods of this application will be clearly and completely described below with reference to the accompanying drawings of the exemplary embodiments of this application. Obviously, the exemplary embodiments described are only some embodiments of this application, and not all embodiments.

[0077] It should be noted that the brief descriptions of terms in this application are only for the convenience of understanding the embodiments described below, and are not intended to limit the embodiments of this application. Unless otherwise stated, these terms should be understood in their ordinary and common meaning.

[0078] The terms "first," "second," "third," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar or related objects or entities, and do not necessarily imply a specific order or sequence, unless otherwise specified. It should be understood that such terms are interchangeable where appropriate.

[0079] The terms “comprising” and “having”, and any variations thereof, are intended to cover but not exclude inclusion, for example, a product or device that includes a range of components is not necessarily limited to all of the components that are clearly listed, but may include other components that are not clearly listed or that are inherent to such product or device.

[0080] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0081] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0082] In related technologies, heat pump air conditioning systems have low suction superheat during defrosting, low-temperature heating start-up, and operation during transitional seasons, which makes it impossible to guarantee the reliability of system operation.

[0083] To address the aforementioned technical issues, this solution integrates a phase change heat storage module into the heat pump air conditioning circulation system. By utilizing the stable phase change temperature and heat storage / release temperature characteristics of the phase change heat storage module, a regenerator function can be achieved, thereby increasing the compressor's suction superheat and improving operational reliability.

[0084] Furthermore, it can increase the subcooling during refrigeration, thereby increasing the overall refrigeration capacity and improving the system's refrigeration efficiency.

[0085] Furthermore, it can increase the superheat during heating, thereby increasing the overall heating capacity and improving the system's heating efficiency.

[0086] Furthermore, it can achieve uninterrupted heating during defrosting.

[0087] Furthermore, time-of-use pricing can be used to store heat in advance, reducing user costs.

[0088] Figure 1 This is a schematic diagram of the structure of a heat pump air conditioning system provided in an embodiment of this application.

[0089] See Figure 1 As shown, this application provides a heat pump air conditioning system.

[0090] The heat pump air conditioning system includes a compressor 100. The compressor 100 is used to draw refrigerant from the low-pressure side, compress it to increase its temperature and pressure, and then push it to the high-pressure side, thus forming a continuous cycle. The compressor 100 plays an important role in this process as a suction, compression, and circulation pump.

[0091] The heat pump air conditioning system includes a four-way valve 200. The four-way valve 200 is used to change the flow path of the refrigerant.

[0092] Specifically, the four-way valve 200 includes a first port, a second port, a third port, and a fourth port. In some states, the first port and the second port are connected, and the third port and the fourth port are connected. In other states, the first port and the fourth port are connected, and the second port and the third port are connected.

[0093] It should be noted that the first port, the second port, the third port, and the fourth port can be arranged in a counterclockwise direction in the diagram.

[0094] The first port of the four-way valve 200 is connected to the compressor 100.

[0095] The heat pump air conditioning system includes an indoor heat exchanger 300. The indoor heat exchanger 300 is located indoors and is used for heat exchange indoors.

[0096] The indoor heat exchanger 300 is connected to the second port of the four-way valve 200.

[0097] The heat pump air conditioning system includes a phase change heat storage module 400. The phase change heat storage module 400 utilizes a phase change material to absorb / release a large amount of latent heat within a phase change temperature range, achieving stable temperature regulation. The phase change heat storage module 400 can be made of paraffin wax, hydrated salts (such as sodium sulfate decahydrate), or composite phase change materials (such as paraffin / graphite composite materials). The phase change material absorbs / releases heat within a specific temperature range (e.g., 42-45℃), maintaining a stable system temperature.

[0098] The phase change heat storage module 400 is connected to the indoor heat exchanger 300 through the first throttling tube group 500. The phase change heat storage module 400 is connected to the compressor 100 through the first tube group 600.

[0099] The heat pump air conditioning system includes an outdoor heat exchanger 700. The outdoor heat exchanger 700 is located outdoors and is used for outdoor heat exchange.

[0100] The outdoor heat exchanger 700 is connected to the phase change heat storage module 400 via a second throttling pipe assembly 800. The first throttling pipe assembly 500 and the second throttling pipe assembly 800 are connected via a second pipe assembly 1100, and one of the first throttling pipe assembly 500 and the second throttling pipe assembly 800 is configured to throttle the refrigerant. The outdoor heat exchanger 700 is connected to the fourth port of the four-way valve 200.

[0101] The heat pump air conditioning system includes a third pipe assembly 900.

[0102] The third pipe group 900 is configured to control the third port of the four-way valve 200 to be connected to or not connected to the compressor 100, and to control the third port of the four-way valve 200 to be connected to or not connected to the phase change heat storage module 400.

[0103] The heat pump air conditioning system includes the fourth pipe group 1000.

[0104] The fourth tube group 1000 is configured to control whether the second port is connected to or not connected to the phase change heat storage module 400.

[0105] It is understood that the heat pump air conditioning system provided in this application includes a compressor 100, a four-way valve 200, an indoor heat exchanger 300, a phase change heat storage module 400, an outdoor heat exchanger 700, a first throttling pipe assembly 500, a second throttling pipe assembly 800, a first pipe assembly 600, a second pipe assembly 1100, a third pipe assembly 900, and a fourth pipe assembly 1000. The first port of the four-way valve 200 is connected to the compressor 100. The indoor heat exchanger 300 is connected to the second port of the four-way valve 200. The phase change heat storage module 400 is connected to the indoor heat exchanger 300 through the first throttling pipe assembly 500. The phase change heat storage module 400 is connected to the compressor 100 through the first pipe assembly 600. The outdoor heat exchanger 700 is connected to the phase change heat storage module 400 through the second throttling pipe assembly 800. The first throttling pipe assembly 500 and the second throttling pipe assembly 800 are connected via the second pipe assembly 1100. One of the first throttling pipe assemblies 500 and 800 is configured to throttle the refrigerant. The outdoor heat exchanger 700 is connected to the fourth port of the four-way valve 200. The third pipe assembly 900 is configured to control whether the third port of the four-way valve 200 is connected to or not connected to the compressor 100, and also to whether the third port of the four-way valve 200 is connected to or not connected to the phase change heat storage module 400. The fourth pipe assembly 1000 is configured to control whether the second port is connected to or not connected to the phase change heat storage module 400.

[0106] Thus, by controlling the refrigerant flow direction through the four-way valve 200, the first throttling pipe assembly 500, the second throttling pipe assembly 800, the third pipe assembly 900, and the fourth pipe assembly 1000, heating regenerative cycle, cooling regenerative cycle, heating superheat cycle, and phase change heat storage defrost cycle can be realized. In the heating and cooling regenerative cycles, the heat released by the phase change heat storage module 400 increases the suction superheat of the compressor 100, improving operational reliability. The heating superheat cycle can increase the superheat of the refrigerant, increase the suction superheat of the compressor 100, improve reliability, increase overall heating capacity, and improve system heating efficiency. The phase change heat storage defrost cycle can utilize the heat released by the phase change heat storage module 400 to increase the suction superheat of the compressor 100, improving operational reliability.

[0107] Furthermore, by controlling the refrigerant flow direction through the four-way valve 200, the first throttling pipe assembly 500, the second throttling pipe assembly 800, the third pipe assembly 900, and the fourth pipe assembly 1000, refrigeration subcooling cycle, heat pump phase change heat storage cycle, and uninterrupted heating cycle can be achieved. The refrigeration subcooling cycle increases the subcooling degree during refrigeration, thereby increasing the overall cooling capacity and improving the system's refrigeration efficiency. The heat pump phase change heat storage cycle can operate during off-peak electricity hours, thus pre-storing heat and reducing user operating costs. The uninterrupted heating cycle enables continuous heating during defrosting.

[0108] See Figure 1As shown, in some embodiments, the first throttling manifold 500 includes a first throttle valve 510. The first throttle valve 510 is used to throttle the refrigerant. The first throttle valve 510 may be an electronic expansion valve.

[0109] The first throttle valve 510 is connected to the indoor heat exchanger 300.

[0110] The first throttling manifold 500 includes a first control valve 520. The first control valve 520 controls the flow of refrigerant by opening and closing it. The first control valve 520 can be a solenoid valve.

[0111] The first control valve 520 is connected to the indoor heat exchanger 300 and is connected in parallel with the first throttle valve 510. The first control valve 520 is configured to control the short circuit or flow of refrigerant in the first throttle valve 510.

[0112] It is understandable that the first throttling tube assembly 500, by setting the first throttling device 510 and the first control valve 520, can determine whether the refrigerant flows through the first throttling device 510 or the first control valve 520, thereby meeting the requirements of different throttling positions of the heat pump air conditioning system.

[0113] The first throttling manifold 500 includes a first three-way valve 530. The first three-way valve 530 is used to control the flow direction of the refrigerant. The first three-way valve 530 can be a three-way switching valve.

[0114] The first three-way valve 530 is connected in series with the first throttle 510 and the first control valve 520, and is connected to the first throttle 510, the first control valve 520, the phase change heat storage module 400, and the second pipe group 1100.

[0115] Understandably, by setting the first three-way valve 530, the connection or disconnection in three different directions can be controlled. Compared with a two-way valve, this helps to simplify the number of components in the heat pump air conditioning system, reduce the overall footprint, and lower costs.

[0116] See Figure 1 As shown, in some embodiments, the second throttling manifold 800 includes a second throttle valve 810. The second throttle valve 810 is used to throttle the refrigerant. The second throttle valve 810 may be an electronic expansion valve.

[0117] The first end of the second throttle 810 is connected to the second pipe group 1100 and the phase change heat storage module 400, respectively, and the second end of the second throttle 810 is connected to the outdoor heat exchanger 700.

[0118] The second throttling manifold 800 includes a second control valve 820. The second control valve 820 controls the flow of refrigerant by switching it on or off. The second control valve 820 can be a solenoid valve.

[0119] The second control valve 820 is connected in parallel with the second throttle valve 810. The first end of the second control valve 820 is connected to both the second pipe assembly 1100 and the phase change heat storage module 400, and the second end is connected to the outdoor heat exchanger 700. The second control valve 820 is configured to control the short circuit or refrigerant flow of the second throttle valve 810.

[0120] It is understandable that the second throttling tube assembly 800, by setting the second throttling device 810 and the second control valve 820, can determine whether the refrigerant flows through the second throttling device 810 or the second control valve 820, thereby meeting the requirements of different throttling positions of the heat pump air conditioning system.

[0121] See Figure 1 As shown, in some embodiments, the first pipe group 600 includes a first connecting pipe, which is connected to the phase change heat storage module 400 and the compressor 100 respectively.

[0122] See Figure 1 As shown, in some embodiments, the second pipe group 1100 includes a second connecting pipe, which is connected to the connecting pipe between the first three-way valve 530 and the second control valve 820 (second throttle 810) in the second throttle pipe group 800 and the phase change heat storage module 400.

[0123] See Figure 1 As shown, in some embodiments, the third pipe assembly 900 includes a second three-way valve 910. The second three-way valve 910 is used to control the flow direction of the refrigerant. The second three-way valve 910 can be a three-way switching valve.

[0124] The second three-way valve 910 is connected to the third port, the phase change heat storage module 400, and the compressor 100, respectively.

[0125] Understandably, by setting the second three-way valve 910, the connection or disconnection in three different directions can be controlled. Compared with the two-way valve, this helps to simplify the number of components in the heat pump air conditioning system, reduce the overall footprint, and lower costs.

[0126] See Figure 1 As shown, in some embodiments, the end of the first pipe group 600 away from the phase change heat storage module 400 is connected to the connecting pipe between the second three-way valve 910 and the compressor 100. That is, the first pipe group 600 and the third pipe group 900 can share part of the connecting pipe, which helps to reduce the overall footprint and reduce costs.

[0127] See Figure 1 As shown, in some embodiments, the fourth pipe assembly 1000 includes a third control valve 1010. The third control valve 1010 controls the flow of refrigerant by switching it on or off. The third control valve 1010 can be a solenoid valve.

[0128] The third control valve 1010 is connected to both the second port and the phase change heat storage module 400. The third control valve 1010 is configured to control whether the second port and the phase change heat storage module 400 are connected or disconnected.

[0129] Figure 2 This is a schematic diagram of the state of a heat pump air conditioning system operating in an uninterrupted heating cycle, as provided in an embodiment of this application.

[0130] See Figure 2 As shown, in some embodiments, when the heat pump air conditioning system operates in defrost mode, the first port is connected to the second port, the first throttling tube group 500 is configured to throttle the refrigerant, the second throttling tube group 800 is configured to allow the refrigerant to flow, and the fourth port is connected to the third port. In other words, the heat pump air conditioning system operates in a continuous heating cycle. This allows for uninterrupted indoor heating during defrosting, with minimal fluctuations in indoor temperature, thus improving the user experience.

[0131] The refrigerant discharged from the compressor 100 is sequentially returned to the compressor 100 via the four-way valve 200, indoor heat exchanger 300, first throttling tube group 500, phase change heat storage module 400, second throttling tube group 800, outdoor heat exchanger 700, four-way valve 200, and third tube group 900.

[0132] Specifically, the refrigerant enters the four-way valve 200 through the compressor 100, the third control valve 1010 is closed, the refrigerant flows through the indoor heat exchanger 300 to exchange heat with the indoor air, then is throttled by the first throttle valve 510, enters the phase change heat storage module 400 through the first three-way valve 530 to absorb heat, after absorbing heat, enters the outdoor heat exchanger 700 through the second control valve 820 to exchange heat with the outdoor air, then enters the second three-way valve 910 through the four-way valve 200, and returns to the compressor 100 to complete the cycle, and the second throttle valve 810 is closed.

[0133] Figure 3 This is a schematic diagram of the state of a heat pump air conditioning system during phase change heat storage defrosting cycle, as provided in an embodiment of this application.

[0134] See Figure 3As shown, in some embodiments, when the heat pump air conditioning system operates in defrost mode, the first port is connected to the second port, and the third port is connected to the fourth port. The first throttling tube group 500 is configured to prevent refrigerant flow, and the second throttling tube group 800 is configured to throttle refrigerant. That is, the heat pump air conditioning system operates a phase change heat storage defrost cycle. This allows the indoor heat exchanger 300 to operate without refrigerant during defrosting, minimizing the impact on indoor temperature and improving user experience. Furthermore, the heat released by the phase change heat storage module 400 can increase the suction superheat of the compressor 100, improving operational reliability.

[0135] The refrigerant discharged from the compressor 100 returns to the compressor 100 sequentially through the four-way valve 200, the outdoor heat exchanger 700, the second throttling pipe group 800, the phase change heat storage module 400, the fourth pipe group 1000, the four-way valve 200, and the third pipe group 900.

[0136] Specifically, the refrigerant enters the four-way valve 200 through the compressor 100, flows through the outdoor heat exchanger 700 to exchange heat with the outdoor air, then flows through the second throttle valve 810 for throttling, the second control valve 820 is closed, enters the phase change heat storage module 400 to absorb heat, and then returns to the four-way valve 200 through the third control valve 1010. Then it returns to the compressor 100 through the second three-way valve 910 to complete the cycle. The first throttle valve 510 and the first control valve 520 are closed.

[0137] Figure 4 This is a schematic diagram of the state of a heat pump air conditioning system during heating and superheating cycles, provided in an embodiment of this application.

[0138] See Figure 4 As shown, in some embodiments, when the heat pump air conditioning system operates in heating mode, the first port is connected to the second port, and the fourth port is connected to the third port. The first throttling tube group 500 is configured to circulate refrigerant, and the second throttling tube group 800 is configured to throttle refrigerant. The refrigerant discharged from the compressor 100 sequentially passes through the four-way valve 200, the indoor heat exchanger 300, the first throttling tube group 500, the second tube group 1100, the second throttling tube group 800, the outdoor heat exchanger 700, the four-way valve 200, the third tube group 900, the phase change heat storage module 400, and the first tube group 600 before returning to the compressor 100. In other words, the heat pump air conditioning system operates in a heating superheat cycle. This can improve the superheat of the refrigerant, improve the suction superheat of the compressor 100, improve reliability, improve the overall heating capacity, and improve the system's heating efficiency.

[0139] Specifically, the refrigerant enters the four-way valve 200 through the compressor 100, the third control valve 1010 is closed, the refrigerant flows through the indoor heat exchanger 300 to exchange heat with the indoor air and then flows out through the first control valve 520, the first throttle valve 510 is closed, and it enters the second throttle valve 810 through the first three-way valve 530 for throttling, the second control valve 820 is closed, and it flows through the outdoor heat exchanger 700 to exchange heat with the outdoor air and then enters the second three-way valve 910 through the four-way valve 200. Then it enters the phase change heat storage module 400 to absorb heat and returns to the compressor 100 to complete the cycle.

[0140] It should be noted that under low-temperature heating conditions, such as when the outdoor temperature is below -7°C, the heat pump air conditioning system operates in a heating overheating cycle, which can be compensated for by using phase change heat storage to compensate for the heating capacity reduction of the heat pump air conditioning system.

[0141] Figure 5 This is a schematic diagram of the state of a heat pump air conditioning system in operation during the heating and regeneration cycle, as provided in an embodiment of this application.

[0142] See Figure 5 As shown, in some embodiments, when the heat pump air conditioning system operates in heating mode, the first port is connected to the second port, and the fourth port is connected to the third port. The first throttling tube group 500 is configured to circulate refrigerant, and the second throttling tube group 800 is configured to throttle refrigerant. The refrigerant discharged from the compressor 100 sequentially passes through the four-way valve 200, the indoor heat exchanger 300, the first throttling tube group 500, the phase change heat storage module 400, the second throttling tube group 800, the outdoor heat exchanger 700, the four-way valve 200, the third tube group 900, the phase change heat storage module 400, and the first tube group 600 before returning to the compressor 100. In other words, the heat pump air conditioning system operates in a heating and regenerative cycle. In this way, the heat released by the phase change heat storage module 400 is used to increase the suction superheat of the compressor 100, thereby improving the reliability of operation.

[0143] Specifically, the refrigerant enters the four-way valve 200 through the compressor 100, the third control valve 1010 is closed, the refrigerant flows through the indoor heat exchanger 300 to exchange heat with the indoor air and then flows out through the first control valve 520. The first throttle valve 510 is closed, and the refrigerant flows through the first three-way valve 530 to the phase change heat storage module 400 to release heat. Then it is throttled by the second throttle valve 810, the second control valve 820 is closed, and the refrigerant flows through the outdoor heat exchanger 700 to exchange heat with the outdoor air and then enters the second three-way valve 910 through the four-way valve 200. Finally, it enters the phase change heat storage module 400 to absorb heat and then returns to the compressor 100 to complete the cycle.

[0144] Figure 6 This is a schematic diagram of the state of a heat pump air conditioning system in normal heating cycle operation, as provided in the embodiments of this application.

[0145] See Figure 6As shown, in some embodiments, when the heat pump air conditioning system operates in heating mode, the first port is connected to the second port, and the fourth port is connected to the third port. The first throttling tube group 500 is configured to allow refrigerant to flow, and the second throttling tube group 800 is configured to allow refrigerant to throttle. The refrigerant discharged from the compressor 100 returns to the compressor 100 sequentially through the four-way valve 200, the indoor heat exchanger 300, the first throttling tube group 500, the second tube group 1100, the second throttling tube group 800, the outdoor heat exchanger 700, the four-way valve 200, and the third tube group 900. In other words, the heat pump air conditioning system operates in a normal heating cycle. Thus, the phase change heat storage module 400 does not need to operate.

[0146] The refrigerant enters the four-way valve 200 through the compressor 100, the third control valve 1010 is closed, the refrigerant flows through the indoor heat exchanger 300 to exchange heat with the indoor air and then flows out through the first control valve 520. The first throttle valve 510 is closed, and the refrigerant enters the second throttle valve 810 through the first three-way valve 530. The second control valve 820 is closed, and the refrigerant flows through the outdoor heat exchanger 700 to exchange heat with the outdoor air and then enters the second three-way valve 910 through the four-way valve 200, returning to the compressor 100 to complete the cycle.

[0147] Figure 7 A schematic diagram of the state of a heat pump air conditioning system operating in a cooling subcooling cycle, as provided in an embodiment of this application.

[0148] See Figure 7 As shown, in some embodiments, when the heat pump air conditioning system operates in cooling mode, the first port is connected to the fourth port, and the second port is connected to the third port. The first throttling tube group 500 is configured to throttle the refrigerant, and the second throttling tube group 800 is configured to allow the refrigerant to flow. The refrigerant discharged from the compressor 100 sequentially passes through the four-way valve 200, the outdoor heat exchanger 700, the second throttling tube group 800, the phase change heat storage module 400, the first throttling tube group 500, the indoor heat exchanger 300, the four-way valve 200, and the third tube group 900 before returning to the compressor 100. In other words, the heat pump air conditioning system operates in a cooling subcooling cycle. This increases the subcooling degree during cooling, thereby increasing the overall cooling capacity and improving the system's cooling energy efficiency.

[0149] The refrigerant enters the four-way valve 200 through the compressor 100, flows through the outdoor heat exchanger 700 to exchange heat with the outdoor air, then flows through the second control valve 820, the second throttle valve 810 is closed, and then enters the phase change heat storage module 400 to release heat. The third control valve 1010 is closed, and after flowing out of the phase change heat storage module 400, it enters the first throttle valve 510 through the first three-way valve 530 for throttling, exchanges heat with the indoor air through the indoor heat exchanger 300, and then enters the second three-way valve 910 through the four-way valve 200, and then returns to the compressor 100 to complete the cycle.

[0150] Figure 8This is a schematic diagram of the state of a heat pump air conditioning system operating in a cooling and heating cycle, as provided in an embodiment of this application.

[0151] See Figure 8 As shown, in some embodiments, when the heat pump air conditioning system operates in cooling mode, the first port is connected to the fourth port, and the second port is connected to the third port. The first throttling tube group 500 is configured to throttle the refrigerant, and the second throttling tube group 800 is configured to allow the refrigerant to flow. The refrigerant discharged from the compressor 100 sequentially passes through the four-way valve 200, the outdoor heat exchanger 700, the second throttling tube group 800, the phase change heat storage module 400, the first throttling tube group 500, the indoor heat exchanger 300, the four-way valve 200, the third tube group 900, the phase change heat storage module 400, and the first tube group 600 before returning to the compressor 100. In other words, the heat pump air conditioning system operates in a cooling-heat recovery cycle. In this way, the heat released by the phase change heat storage module 400 is used to increase the suction superheat of the compressor 100, thereby improving the reliability of operation.

[0152] The refrigerant enters the four-way valve 200 through the compressor 100, flows through the outdoor heat exchanger 700 to exchange heat with the outdoor air, then flows through the second control valve 820, the second throttle valve 810 is closed, and then enters the phase change heat storage module 400 to release heat. The third control valve 1010 is closed, and after flowing out of the phase change heat storage module 400, it enters the first throttle valve 510 through the first three-way valve 530 for throttling, then flows through the indoor heat exchanger 300 to exchange heat with the indoor air, then enters the second three-way valve 910 through the four-way valve 200, and then enters the phase change heat storage module 400 to absorb heat before returning to the compressor 100 to complete the cycle.

[0153] Figure 9 This is a schematic diagram of the state of a heat pump air conditioning system during normal refrigeration cycle operation, provided in an embodiment of this application.

[0154] See Figure 9 As shown, in some embodiments, when the heat pump air conditioning system operates in cooling mode, the first port is connected to the fourth port, and the second port is connected to the third port. The first throttling tube group 500 is configured to throttle the refrigerant, and the second throttling tube group 800 is configured to allow the refrigerant to flow. The refrigerant discharged from the compressor 100 returns to the compressor 100 sequentially through the four-way valve 200, the outdoor heat exchanger 700, the second throttling tube group 800, the second tube group 1100, the first throttling tube group 500, the indoor heat exchanger 300, the four-way valve 200, and the third tube group 900. In other words, the heat pump air conditioning system operates in a normal cooling cycle. Thus, the phase change heat storage module 400 does not need to operate.

[0155] The refrigerant enters the four-way valve 200 through the compressor 100, flows through the outdoor heat exchanger 700 to exchange heat with the outdoor air, then flows through the second control valve 820, the second throttle valve 810 is closed, and then enters the first throttle valve 510 through the first three-way valve 530 for throttling. After exchanging heat with the indoor air through the indoor heat exchanger 300, it enters the second three-way valve 910 through the four-way valve 200 and returns to the compressor 100 to complete the cycle.

[0156] Figure 10 This is a schematic diagram of the state of a heat pump air conditioning system operating in phase change heat storage cycle, as provided in an embodiment of this application.

[0157] See Figure 10 As shown, in some embodiments, when the heat pump air conditioning system operates in phase change heat storage mode, the first port is connected to the second port, and the third port is connected to the fourth port. The first throttling tube group 500 is configured to prevent refrigerant flow, and the second throttling tube group 800 is configured to allow refrigerant to flow. In other words, the heat pump air conditioning system operates in phase change heat storage cycle. This allows the phase change heat storage module 400 to store heat.

[0158] The refrigerant discharged from the compressor 100 returns to the compressor 100 sequentially through the four-way valve 200, the fourth pipe group 1000, the phase change heat storage module 400, the second throttling pipe group 800, the outdoor heat exchanger 700, the four-way valve 200, and the third pipe group 900.

[0159] Specifically, the refrigerant enters the four-way valve 200 through the compressor 100, flows through the outdoor heat exchanger 700 to exchange heat with the outdoor air, then flows through the second control valve 820, the second throttle valve 810 is closed, and then enters the first throttle valve 510 through the first three-way valve 530 for throttling. After exchanging heat with the indoor air through the indoor heat exchanger 300, it enters the second three-way valve 910 through the four-way valve 200 and returns to the compressor 100 to complete the cycle.

[0160] Understandably, heat pump phase change thermal storage cycles can operate during off-peak electricity periods, thereby storing heat in advance and reducing user costs.

[0161] In some embodiments, the heat pump air conditioning system includes a controller. Compressor 100, four-way valve 200, first throttle 510, first control valve 520, first three-way valve 530, second throttle 810, second control valve 820, second three-way valve 910, and third control valve 1010 are all electrically connected to the controller. The controller is configured to control the operating state of compressor 100, four-way valve 200, first throttle 510, first control valve 520, first three-way valve 530, second throttle 810, second control valve 820, second three-way valve 910, and third control valve 1010 according to the cycle type of the heat pump air conditioning system.

[0162] In some embodiments, a control method for a heat pump air conditioning system is provided, comprising:

[0163] Based on the operating cycle type of the heat pump air conditioning system, control the operating status of compressor 100, four-way valve 200, first throttle valve 510, first control valve 520, first three-way valve 530, second throttle valve 810, second control valve 820, second three-way valve 910 and third control valve 1010.

[0164] In some embodiments, a computer-readable storage medium is provided, which stores computer-executable instructions that, when executed by a processor, are used to implement the methods described above.

[0165] In some embodiments, a computer program product is provided, including a computer program that, when executed by a processor, implements the method described above.

[0166] Those skilled in the art will also understand that the various illustrative logic blocks and steps listed in the embodiments of this disclosure can be implemented by electronic hardware, computer software, or a combination of both. Whether such functionality is implemented in hardware or software depends on the specific application and the overall system design requirements. Those skilled in the art can implement this functionality using various methods for each specific application, but such implementation should not be construed as exceeding the scope of protection of the embodiments of this disclosure.

[0167] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0168] For ease of explanation, the above description has been provided in conjunction with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or to limit the embodiments to the specific forms disclosed above. Various modifications and variations can be obtained based on the above teachings. The selection and description of the above embodiments are for the purpose of better explaining the principles and practical applications, thereby enabling those skilled in the art to better utilize the described embodiments and various different variations of embodiments suitable for specific use considerations.

Claims

1. A heat pump air conditioning system, characterized in that, include: Compressor (100); A four-way valve (200) has its first port connected to the compressor (100); The indoor heat exchanger (300) is connected to the second port of the four-way valve (200); The phase change heat storage module (400) is connected to the indoor heat exchanger (300) through the first throttling tube group (500); the phase change heat storage module (400) is connected to the compressor (100) through the first tube group (600); the phase change heat storage module (400) is connected to the second tube group (1100); The outdoor heat exchanger (700) is connected to the phase change heat storage module (400) through a second throttling tube group (800), and the first throttling tube group (500) and the second throttling tube group (800) are connected through a second tube group (1100). One of the first throttling tube group (500) and the second throttling tube group (800) is configured to throttle the refrigerant. The outdoor heat exchanger (700) is connected to the fourth port of the four-way valve (200). The third pipe assembly (900) is configured to control the third port of the four-way valve (200) to be connected to or not connected to the compressor (100), and to control the third port of the four-way valve (200) to be connected to or not connected to the phase change heat storage module (400); The fourth tube group (1000) is configured to control whether the second port is connected to or not connected to the phase change thermal storage module (400); The first throttling tube assembly (500) includes: The first throttle (510) is connected to the indoor heat exchanger (300); The first control valve (520) is connected to the indoor heat exchanger (300), and the first control valve (520) is connected in parallel with the first throttle (510). The first control valve (520) is configured to control the short circuit or flow of refrigerant in the first throttle (510). The first three-way valve (530) is connected in series with the first throttle (510) and the first control valve (520), respectively. The first three-way valve (530) is connected to the first throttle (510), the first control valve (520), the fourth pipe group (1000), and the second pipe group (1100), respectively.

2. The heat pump air conditioning system according to claim 1, characterized in that, The second throttling tube assembly (800) includes: The second throttle (810) has its first end connected to the second tube group (1100) and the phase change heat storage module (400) respectively, and its second end connected to the outdoor heat exchanger (700). The second control valve (820) is connected in parallel with the second throttle (810). The first end of the second control valve (820) is connected to the second pipe group (1100) and the phase change heat storage module (400) respectively, and the second end of the second control valve (820) is connected to the outdoor heat exchanger (700). The second control valve (820) is configured to control the short circuit or flow of refrigerant in the second throttle (810).

3. The heat pump air conditioning system according to claim 1, characterized in that, The third pipe group (900) includes: The second three-way valve (910) is connected to the third port, the phase change heat storage module (400), and the compressor (100), respectively.

4. The heat pump air conditioning system according to claim 1, characterized in that, The fourth tube group (1000) includes: The third control valve (1010) is connected to the second port and the phase change heat storage module (400) respectively.

5. The heat pump air conditioning system according to claim 3, characterized in that, The end of the first pipe assembly (600) away from the phase change heat storage module (400) is connected to the connecting pipe between the second three-way valve (910) and the compressor (100).

6. The heat pump air conditioning system according to any one of claims 1 to 5, characterized in that, When the heat pump air conditioning system is in defrost mode, the first throttling pipe group (500) is configured to throttle the refrigerant, and the second throttling pipe group (800) is configured to allow the refrigerant to flow. The refrigerant discharged from the compressor (100) passes through the four-way valve (200), the indoor heat exchanger (300), the first throttling pipe group (500), the phase change heat storage module (400), the second throttling pipe group (800), the outdoor heat exchanger (700), the four-way valve (200), and the third pipe group (900) in sequence and returns to the compressor (100). Alternatively, the first throttling pipe assembly (500) is configured to not circulate refrigerant, and the second throttling pipe assembly (800) is configured to throttle refrigerant; the refrigerant discharged from the compressor (100) returns to the compressor (100) in sequence through the four-way valve (200), the outdoor heat exchanger (700), the second throttling pipe assembly (800), the phase change heat storage module (400), the fourth pipe assembly (1000), the four-way valve (200), and the third pipe assembly (900).

7. The heat pump air conditioning system according to any one of claims 1 to 5, characterized in that, When the heat pump air conditioning system is operating in heating mode, the first throttling tube group (500) is configured to circulate refrigerant, and the second throttling tube group (800) is configured to throttle refrigerant. The refrigerant discharged from the compressor (100) passes through the four-way valve (200), indoor heat exchanger (300), first throttling tube group (500), second tube group (1100), second throttling tube group (800), outdoor heat exchanger (700), four-way valve (200), third tube group (900), phase change heat storage module (400) and first tube group (600) before returning to the compressor (100). Alternatively, the refrigerant discharged from the compressor (100) may return to the compressor (100) in sequence via a four-way valve (200), an indoor heat exchanger (300), a first throttling tube assembly (500), a phase change heat storage module (400), a second throttling tube assembly (800), an outdoor heat exchanger (700), a four-way valve (200), a third tube assembly (900), a phase change heat storage module (400), and a first tube assembly (600). Alternatively, the refrigerant discharged from the compressor (100) returns to the compressor (100) in sequence via the four-way valve (200), indoor heat exchanger (300), first throttling pipe group (500), second pipe group (1100), second throttling pipe group (800), outdoor heat exchanger (700), four-way valve (200) and third pipe group (900).

8. The heat pump air conditioning system according to any one of claims 1 to 5, characterized in that, When the heat pump air conditioning system is operating in cooling mode, the first throttling tube group (500) is configured to throttle the refrigerant, and the second throttling tube group (800) is configured to allow the refrigerant to flow. The refrigerant discharged from the compressor (100) returns to the compressor (100) in sequence through the four-way valve (200), outdoor heat exchanger (700), second throttling tube group (800), phase change heat storage module (400), first throttling tube group (500), indoor heat exchanger (300), four-way valve (200) and third tube group (900). Alternatively, the refrigerant discharged from the compressor (100) passes sequentially through the four-way valve (200), outdoor heat exchanger (700), second throttling pipe assembly (800), phase change heat storage module (400), first throttling pipe assembly (500), indoor heat exchanger (300), four-way valve (200) and third pipe assembly (900), phase change heat storage module (400), and first pipe assembly (600) back to the compressor (100). Alternatively, the refrigerant discharged from the compressor (100) returns to the compressor (100) in sequence via the four-way valve (200), the outdoor heat exchanger (700), the second throttling pipe group (800), the second pipe group (1100), the first throttling pipe group (500), the indoor heat exchanger (300), the four-way valve (200), and the third pipe group (900).

9. The heat pump air conditioning system according to any one of claims 1 to 5, characterized in that, When the heat pump air conditioning system is operating in phase change heat storage mode, the first throttling tube group (500) is configured to not circulate refrigerant, and the second throttling tube group (800) is configured to throttle refrigerant. The refrigerant discharged from the compressor (100) returns to the compressor (100) in sequence through the four-way valve (200), the fourth pipe group (1000), the phase change heat storage module (400), the second throttling pipe group (800), the outdoor heat exchanger (700), the four-way valve (200), and the third pipe group (900).

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