Air source heat pump unit

Abstract

This application discloses an air source heat pump unit, belonging to the field of heat pump technology. The air source heat pump unit includes an indoor heat exchanger, a four-way valve, a compressor, an outdoor heat exchanger, an expansion valve, an antifreeze pipeline, a three-way valve, and a controller. The indoor heat exchanger is used for heat exchange with indoor air; the compressor is used to drive the refrigerant flow; the four-way valve is used to switch the refrigerant flow direction; the outdoor heat exchanger is used for heat exchange with outdoor air; the expansion valve is used to throttle the refrigerant flowing into the outdoor heat exchanger; the antifreeze pipeline is used for defrosting the outdoor heat exchanger; the three-way valve is used to connect or disconnect the antifreeze pipeline and the first pipeline; the controller is used to control the three-way valve to connect the first pipeline and disconnect the antifreeze pipeline from the first pipeline when the refrigerant flows from the outdoor heat exchanger to the indoor heat exchanger; and to control the three-way valve to connect the antifreeze pipeline and the first pipeline when the refrigerant flows from the indoor heat exchanger to the outdoor heat exchanger, thereby improving the cooling and heating effect of the air source heat pump unit.

Description

Technical Field

[0001] This application relates to the field of air source heat pump technology, and more particularly to an air source heat pump unit. Background Technology

[0002] An air source heat pump unit is an energy-saving device that utilizes high-grade energy to transfer heat from a low-grade heat source (air) to a high-grade heat source. It uses refrigerant to absorb low-grade heat energy from the ambient air in the evaporator and vaporize it. After being compressed into a high-temperature, high-pressure gas by the compressor, the gas releases heat in the condenser to supply indoor heating or hot water systems. This system only consumes a small amount of electricity to drive the compressor, yet it can achieve a heat energy transfer several times greater than the input energy. It provides efficient heating in winter and can also achieve cooling in summer by switching the circulation direction using a four-way valve. It is a highly efficient and energy-saving integrated heating and cooling device.

[0003] In existing low-temperature air source heat pump units, long-term operation in a low-temperature environment can cause ice to form at the bottom of the heat exchanger, which is difficult to remove. This will significantly reduce the unit's heating effect and affect the performance of the air source heat pump unit.

[0004] In view of the above, this application is hereby submitted. Summary of the Invention

[0005] To address the shortcomings of related technologies, this application provides an air source heat pump unit. By configuring antifreeze piping and a three-way valve on the basis of a traditional air source heat pump unit, and controlling the opening of the three-way valve through a controller, the outdoor heat exchanger is defrosted and ice is prevented from forming at the bottom of the outdoor heat exchanger while ensuring the cooling and heating effect of the air source heat pump unit.

[0006] This application provides an air source heat pump unit, including:

[0007] An indoor heat exchanger, comprising a first connecting port and a second connecting port;

[0008] A four-way valve is used to switch the direction of refrigerant flow. The four-way valve includes a first reversing port, a second reversing port, a third reversing port and a fourth reversing port. The second reversing port is connected to the first connecting port.

[0009] The compressor is used to drive the flow of refrigerant; the inlet end of the compressor is connected to the third reversing port, and the discharge end of the compressor is connected to the first reversing port.

[0010] The outdoor heat exchanger includes a third connection port and a fourth connection port. The fourth connection port is connected to the fourth diversion liquid port. The third connection port is connected to the second connection port through a first pipeline.

[0011] An expansion valve, located on the first pipeline, is used to throttle the refrigerant flowing into the outdoor heat exchanger;

[0012] The antifreeze pipeline, at least part of which is located at the bottom of the outdoor heat exchanger; the inlet and outlet ends of the antifreeze pipeline are respectively connected to the first pipeline and located on the side of the expansion valve near the indoor heat exchanger.

[0013] A three-way valve is located at the connection point between the inlet end of the antifreeze pipeline and the first pipeline, and is used to connect or disconnect the antifreeze pipeline and the first pipeline as well as to control the on / off state of the first pipeline.

[0014] The controller is connected to the three-way valve, and the controller is configured as follows:

[0015] When the refrigerant flows from the outdoor heat exchanger to the indoor heat exchanger, the three-way valve is controlled to connect the first pipeline and disconnect the antifreeze pipeline from the first pipeline;

[0016] When the refrigerant flows from the indoor heat exchanger to the outdoor heat exchanger, the three-way valve is controlled to connect the antifreeze pipeline to the first pipeline.

[0017] This technical solution, by setting up antifreeze piping and a three-way valve, allows the air source heat pump unit to control the three-way valve to connect the first piping and disconnect the antifreeze piping from the first piping when cooling the indoor environment. This prevents refrigerant from flowing into the indoor heat exchanger through the first piping without passing through the antifreeze piping, thus preventing unnecessary heat loss caused by refrigerant entering the antifreeze piping. When the air source heat pump unit is heating the indoor environment, the controller controls the three-way valve to connect the antifreeze piping to the first piping, allowing a portion of the high-pressure refrigerant to enter the outdoor heat exchanger through the antifreeze piping. The waste heat of the high-pressure refrigerant is then used to defrost the outdoor heat exchanger.

[0018] In some embodiments, the three-way valve includes port A, port B and port C, with port A and port B respectively connected to the first pipeline, and port C connected to the inlet end of the antifreeze pipeline;

[0019] The controller is configured to: control the connection between port A and port B to connect the first pipeline; control the connection between port A and port C to connect the antifreeze pipeline and the first pipeline; control the disconnection of port B to disconnect the first pipeline; and control the disconnection of port C to disconnect the antifreeze pipeline and the first pipeline.

[0020] This technical solution uses a controller to control the different states of ports A, B, and C of a three-way valve to connect or disconnect the first pipeline, or connect or disconnect the first pipeline and the antifreeze pipeline, so as to achieve differentiated flow path design when the refrigerant flows into or out of the outdoor heat exchanger 300.

[0021] In some embodiments, when the three-way valve is opened to the first opening degree, port A is located near the indoor heat exchanger and port B is located near the outdoor heat exchanger; port A and port B are connected and port C is cut off; when the three-way valve is opened to the second opening degree, port A and port C are connected and port B is cut off.

[0022] The controller is further configured to control the three-way valve to operate at a first opening degree when the refrigerant flows from the outdoor heat exchanger to the indoor heat exchanger;

[0023] When the refrigerant flows from the indoor heat exchanger to the outdoor heat exchanger, the control three-way valve first operates at the second opening degree for a first time tq, and then the valve opening degree of the three-way valve is judged in real time according to the outdoor ambient temperature Ta and the capillary temperature Te of the outdoor heat exchanger.

[0024] This technical solution uses a controller to control the different states of ports A, B, and C of a three-way valve to achieve different valve opening degrees. When the air source heat pump unit is cooling the indoor environment, the controller controls the three-way valve to connect ports A and B while shutting off port C, so that the three-way valve operates at the first opening degree. This allows the refrigerant to enter the indoor heat exchanger through the first pipeline without passing through the antifreeze pipe, thus preventing unnecessary heat loss when the air source heat pump unit is cooling the indoor environment. During the start-up phase when the air source heat pump unit is heating the indoor environment, since the frosting status of the outdoor heat exchanger is unknown, the controller needs to control the three-way valve to connect ports A and C while shutting off port B, so that the three-way valve operates at the second opening degree. This allows the high-pressure refrigerant to enter the outdoor heat exchanger through the antifreeze pipe, using the residual heat of the high-pressure refrigerant to defrost the outdoor heat exchanger and avoid affecting the heating effect due to frosting of the outdoor heat exchanger.

[0025] In some embodiments, the controller is further configured to: acquire the outdoor ambient temperature Ta and the outdoor heat exchanger capillary temperature Te, and obtain a reference temperature Tc1 based on the outdoor ambient temperature Ta; if the outdoor heat exchanger capillary temperature Te is less than or equal to the reference temperature Tc1, control the three-way valve to operate at a second opening degree; if the outdoor heat exchanger capillary temperature Te is greater than the reference temperature Tc1, calculate the opening degree of the three-way valve according to the opening degree formula.

[0026] This technical solution uses a controller to acquire the outdoor ambient temperature Ta and the capillary temperature Te of the outdoor heat exchanger in real time. Based on the outdoor ambient temperature Ta and the reference temperature Tc1, it determines the frosting condition of the outdoor heat exchanger and controls the opening of the three-way valve accordingly. If the outdoor heat exchanger is severely frosted, the three-way valve is controlled to operate at a second opening, allowing high-pressure refrigerant to enter the outdoor heat exchanger through the antifreeze pipe. The residual heat of the high-pressure refrigerant is then used to defrost the outdoor heat exchanger. If the frosting on the outdoor heat exchanger pipe surface is minor or non-frosted, the opening of the three-way valve is calculated according to the opening formula. Part of the refrigerant flows into the outdoor heat exchanger through the first pipe, and part flows through the antifreeze pipe. The proportion of refrigerant flowing through the antifreeze pipe needs to be determined based on the capillary temperature Te of the outdoor heat exchanger to ensure that an appropriate proportion of refrigerant flows into the antifreeze pipe based on the frosting condition of the outdoor heat exchanger, utilizing the residual heat of the high-pressure refrigerant to defrost the outdoor heat exchanger and prevent further frosting.

[0027] In some embodiments, the controller is further configured to: acquire the outdoor ambient temperature Ta and the outdoor heat exchanger capillary temperature Te in real time, so as to determine the opening degree of the three-way valve in real time.

[0028] Calculate the duration of the outdoor heat exchanger capillary temperature Te being less than or equal to the reference temperature Tc1;

[0029] If the duration is greater than the second time tj, the valve opening of the three-way valve is controlled to be the second opening, and the air source heat pump unit enters the defrosting mode.

[0030] If the duration is less than the second time tj, the opening degree of the three-way valve is determined in real time based on the outdoor ambient temperature Ta and the outdoor heat exchanger capillary temperature Te.

[0031] This technical solution uses a controller to determine whether the outdoor heat exchanger pipe surface is still severely frosted by judging whether the duration for which the outdoor heat exchanger capillary temperature Te is less than or equal to the reference temperature Tc1 is greater than the second time tj. If the outdoor heat exchanger surface is severely frosted, the controller controls the air source heat pump unit to enter defrost mode and controls the three-way valve to operate at the second opening degree, so that the high-pressure refrigerant flows into the antifreeze pipe and uses the residual heat of the high-pressure refrigerant to defrost the outdoor heat exchanger pipe surface. If the degree of frosting on the outdoor heat exchanger surface is small or there is no frost on the outdoor heat exchanger surface, it is necessary to continue to acquire the outdoor ambient temperature Ta and the outdoor heat exchanger capillary temperature Te in real time to judge the valve opening degree of the three-way valve in real time to prevent the outdoor heat exchanger from frosting at any time.

[0032] In some embodiments, the controller is further configured to control the three-way valve to operate at a first opening degree when the capillary temperature Te of the outdoor heat exchanger reaches a set value, and the air source heat pump unit exits the defrosting mode.

[0033] This technical solution uses a controller to determine whether the outdoor capillary temperature Te has reached the set value to decide whether the defrosting mode of the air source heat pump unit has ended. After the defrosting mode is completed, the controller controls the three-way valve to operate at the first opening degree to prevent refrigerant from flowing into the antifreeze pipeline and avoid heat loss caused by continuous unnecessary defrosting operation of the air source heat pump unit.

[0034] In some embodiments, the controller is further configured to: acquire the defrost mode running time after the air source heat pump unit exits the defrost mode;

[0035] If the defrosting mode running time is less than or equal to the first reference value, the opening degree of the three-way valve is determined in real time based on the outdoor ambient temperature Ta and the outdoor heat exchanger capillary temperature Te.

[0036] If the defrosting mode operation time is longer than the first reference value, the three-way valve is controlled to operate at the second opening for a third time. Then, the opening of the three-way valve is determined in real time based on the outdoor ambient temperature Ta and the outdoor heat exchanger capillary temperature Te.

[0037] This technical solution determines the amount of condensate accumulated in the antifreeze pipes of the air source heat pump unit after defrosting by measuring the defrosting mode running time. If the defrosting mode running time is longer than the first reference value, it indicates that there is a lot of condensate accumulated in the antifreeze pipes. In this case, the three-way valve opening needs to be controlled to operate at the second opening for a third time, so that the high-pressure refrigerant enters the outdoor heat exchanger from the antifreeze pipes for a period of time. The residual heat of the high-pressure refrigerant is used to prevent the condensate in the antifreeze pipes from freezing and affecting the heating effect. If the defrosting mode running time is shorter than the first reference value, it indicates that there is less condensate accumulated in the antifreeze pipes at the current moment. In this case, the valve opening needs to be continuously adjusted in real time based on the outdoor ambient temperature Ta and the capillary temperature Te of the outdoor heat exchanger at the next moment to prevent the antifreeze pipes from freezing at any time.

[0038] In some embodiments, the defrost mode runtime is positively correlated with the third time.

[0039] The controller is further configured to calculate a third time based on the running time of the defrost mode.

[0040] This technical solution determines the duration of the three-way valve operating at its second opening based on the defrosting mode's operating time. This ensures that the condensate accumulated in the antifreeze pipes of the air source heat pump unit will not freeze, and that excessive refrigerant will not flow into the antifreeze pipes, thus preventing unnecessary heat loss.

[0041] In some embodiments, the antifreeze pipeline is equipped with a one-way valve, which is connected to a controller. The controller is further configured to: control the one-way valve to cut off the antifreeze pipeline when the refrigerant flows from the outdoor heat exchanger to the indoor heat exchanger; and control the one-way valve to connect the antifreeze pipeline when the refrigerant flows from the indoor heat exchanger to the outdoor heat exchanger.

[0042] This technical solution controls a one-way valve to cut off the antifreeze pipeline, preventing refrigerant from flowing back into the antifreeze pipeline and causing refrigerant deposition in the antifreeze pipeline, which would affect the cooling or heating effect of the air source heat pump unit. When the air source heat pump unit is heating the indoor environment, the controller controls the one-way valve to connect the antifreeze pipeline, so that the refrigerant entering the antifreeze pipeline can enter the outdoor heat exchanger through the first pipeline.

[0043] This application also provides an air source heat pump unit, including:

[0044] An indoor heat exchanger, comprising a first connecting port and a second connecting port;

[0045] A four-way valve is used to switch the direction of refrigerant flow. The four-way valve includes a first reversing port, a second reversing port, a third reversing port and a fourth reversing port. The second reversing port is connected to the first connecting port.

[0046] The compressor is used to drive the flow of refrigerant; the inlet end of the compressor is connected to the third reversing port, and the discharge end of the compressor is connected to the first reversing port.

[0047] The outdoor heat exchanger includes a third connection port and a fourth connection port. The fourth connection port is connected to the fourth diversion liquid port. The third connection port is connected to the second connection port through a first pipeline.

[0048] An expansion valve, located on the first pipeline, is used to throttle the refrigerant flowing into the outdoor heat exchanger;

[0049] The antifreeze pipeline, at least part of which is located at the bottom of the outdoor heat exchanger; the inlet and outlet ends of the antifreeze pipeline are respectively connected to the first pipeline and located on the side of the expansion valve near the indoor heat exchanger.

[0050] The three-way valve includes ports A, B, and C. Ports A and B are connected to the first pipeline, and port C is connected to the inlet end of the antifreeze pipeline.

[0051] The controller is connected to the three-way valve, and the controller is configured as follows:

[0052] When the refrigerant flows from the outdoor heat exchanger to the indoor heat exchanger, control port A to connect with port B and cut off port C;

[0053] When the refrigerant flows from the indoor heat exchanger to the outdoor heat exchanger, first control the connection between port A and port C and cut off port B. After a period of time, the status of port A, port B and port C is judged in real time based on the outdoor ambient temperature Ta and the capillary temperature Te of the outdoor heat exchanger.

[0054] This technical solution involves installing antifreeze piping and a three-way valve. A controller manages the states of ports A, B, and C of the three-way valve. When the air source heat pump unit is cooling the indoor environment, ports A and B are connected, while port C is disconnected. This prevents refrigerant from flowing into the indoor heat exchanger via the first piping, thus preventing unnecessary heat loss due to refrigerant entering the antifreeze piping. When the air source heat pump unit is heating the indoor environment, ports A and C are connected first, while port B is disconnected. This allows high-pressure refrigerant to enter through the antifreeze piping when the frosting status of the outdoor heat exchanger is unknown. The high-pressure refrigerant enters the outdoor heat exchanger and uses its residual heat for defrosting to prevent frost buildup. To prevent excessive refrigerant from entering the antifreeze piping without knowing the extent of frost, causing unnecessary heat loss, the frost condition of the outdoor heat exchanger needs to be assessed in real time based on the outdoor ambient temperature Ta and the capillary temperature Te of the outdoor heat exchanger. The states of ports A, B, and C of the three-way valve are then controlled according to the frost condition to allow an appropriate proportion of high-pressure refrigerant to enter the outdoor heat exchanger through the antifreeze piping, using the residual heat of the high-pressure refrigerant to defrost the outdoor heat exchanger.

[0055] The above embodiment configures antifreeze pipes and a three-way valve on the basis of a traditional air source heat pump unit, and controls the opening of the three-way valve through a controller to achieve the overall defrosting function of the outdoor heat exchanger of the air source heat pump unit and the antifreeze function of the bottom of the outdoor heat exchanger while ensuring the cooling and heating effect of the air source heat pump unit. Attached Figure Description

[0056] Figure 1 This is a schematic diagram of the air source heat pump unit in this application;

[0057] Figure 2 This is a schematic diagram of the refrigerant flow path during cooling in the air source heat pump unit of this application;

[0058] Figure 3 This is a schematic diagram of the refrigerant flow path during heating in the air source heat pump unit of this application;

[0059] Figure 4 This is a structural diagram of the three-way valve of the air source heat pump unit in this application;

[0060] Figure 5 This is a schematic diagram of an air source heat pump unit with a subcooling section as described in this application;

[0061] Figure 6 This is a schematic diagram of the refrigerant flow path during cooling in the air source heat pump unit with a subcooling section as described in this application.

[0062] Figure 7 This is a schematic diagram of the refrigerant flow path when the air source heat pump unit with a subcooling section in this application is heating.

[0063] Figure 8This is a flowchart of the normal operation phase of the air source heat pump unit in this application;

[0064] Figure 9 This is a flowchart of the post-defrost operation phase of the air source heat pump unit in this application;

[0065] Figure 10 This is a diagram showing the interval division of defrosting time during the operation phase after defrosting of the air source heat pump unit in this application.

[0066] In the picture,

[0067] 100. Indoor heat exchanger; 200. Compressor; 300. Outdoor heat exchanger; 400. Four-way valve; 500. Subcooling section; 600. Expansion valve; 700. Antifreeze piping; 800. Three-way valve; 900. Check valve; 1000. Controller;

[0068] 110. First pipeline; 111. Second pipeline;

[0069] 210. Third pipeline; 211. Fourth pipeline;

[0070] 310. Fifth pipeline; 311. Sixth pipeline;

[0071] 510. Seventh pipeline;

[0072] 801. Drive motor; 802. Valve stem; 803. Valve core. Detailed Implementation

[0073] 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.

[0074] 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.

[0075] The terms "first," "second," 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.

[0076] The terms “include” and “have”, and any variations thereof, are intended to cover but not exclusively include, 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.

[0077] The air source heat pump unit provided in this application can have various implementation forms. For example... Figures 1-10 This is a specific embodiment of the air source heat pump unit of this application.

[0078] The air source heat pump unit includes an indoor heat exchanger 100, which is located indoors and is used to exchange heat with indoor air. A refrigerant for exchanging heat with the air flows inside the indoor heat exchanger 100. When the air source heat pump unit is cooling, the indoor heat exchanger 100 operates as an evaporator, where the refrigerant evaporates and absorbs heat, thereby lowering the indoor temperature. When the air source heat pump unit is heating, the indoor heat exchanger 100 acts as a condenser, where the refrigerant condenses and releases heat, thereby raising the indoor temperature.

[0079] like Figure 1 As shown, the indoor heat exchanger 100 includes a first connection port, which is connected to a second pipe 111. When the indoor heat exchanger 100 operates as an evaporator, the refrigerant flows out of the indoor heat exchanger 100 from the first connection port through the second pipe 111. When the indoor heat exchanger 100 operates as a condenser, the refrigerant flows into the indoor heat exchanger 100 from the first connection port through the second pipe 111.

[0080] like Figure 1 and Figure 2 As shown, the indoor heat exchanger 100 includes a second connection port, which is connected to the first pipe 110. The indoor heat exchanger 100 is connected to the outdoor heat exchanger 300 through the first pipe 110. When the indoor heat exchanger 100 is working as an evaporator, the refrigerant flows into the indoor heat exchanger 100 from the second connection port through the first pipe 110. When the indoor heat exchanger 100 is working as a condenser, the refrigerant flows out of the indoor heat exchanger 100 from the second connection port through the first pipe 110.

[0081] like Figure 1 As shown, the air source heat pump unit includes a compressor 200, which is used to compress refrigerant gas in a low temperature and low pressure state into refrigerant gas in a high temperature and high pressure state. The compressor 200 provides power for the circulation of refrigerant in the pipeline.

[0082] The compressor 200 includes a discharge port. The refrigerant in a low-temperature, low-pressure state is compressed into a high-temperature, high-pressure state and then discharged from the compressor 200 through the discharge port. The discharge port is connected to a third pipe 210 so that the high-temperature, high-pressure refrigerant flows to the outdoor heat exchanger 300 through the third pipe 210.

[0083] The compressor 200 includes a return port through which refrigerant in a low-temperature, low-pressure state enters the compressor 200. The return port is connected to a fourth pipe 211, which allows the low-temperature, low-pressure refrigerant to flow back to the compressor 200.

[0084] like Figure 1 As shown, the air source heat pump unit includes an outdoor heat exchanger 300, which is located outdoors and is used to exchange heat with the outdoor air. When the air source heat pump unit is in cooling mode, the outdoor heat exchanger 300 works as a condenser, condensing the high-temperature, high-pressure gaseous refrigerant into a medium-temperature, high-pressure liquid refrigerant. When the air source heat pump unit is in heating mode, the outdoor heat exchanger 300 works as an evaporator, evaporating the low-temperature, low-pressure liquid refrigerant into a low-temperature, low-pressure gaseous refrigerant.

[0085] The outdoor heat exchanger 300 includes a third connection port, which is connected to the end of the first pipe 110 away from the second connection port. When the outdoor heat exchanger 300 is working as a condenser, the refrigerant flows out of the outdoor heat exchanger 300 through the third connection port and flows into the indoor heat exchanger 100 through the first pipe 110. When the outdoor heat exchanger 300 is working as an evaporator, the refrigerant flows into the outdoor heat exchanger 300 through the third connection port via the first pipe 110.

[0086] An expansion valve 600 is provided in the first pipeline 110. The expansion valve 600 is located between the outdoor heat exchanger 300 and the indoor heat exchanger 100. The expansion valve 600 is used to throttle the refrigerant flowing from the outdoor heat exchanger 300 to the indoor heat exchanger 100. The high-pressure refrigerant is converted into low-pressure refrigerant after being throttled by the expansion valve 600.

[0087] The outdoor heat exchanger 300 includes a fourth connection port, which is connected to a fifth pipe 310. When the outdoor heat exchanger 300 is working as a condenser, the refrigerant flows into the outdoor heat exchanger 300 from the fourth connection port through the fifth pipe 310. When the outdoor heat exchanger 300 is working as an evaporator, the refrigerant flows out of the outdoor heat exchanger 300 from the fourth connection port through the fifth pipe 310.

[0088] In some embodiments, the outdoor heat exchanger 300 is a finned heat exchanger, which includes heat exchange tubes through which refrigerant flows; the finned heat exchanger includes fins for the heat exchange tubes to pass through, thereby increasing the contact area between the heat exchange tubes and the air.

[0089] Since the refrigerant flows differently when the air source heat pump unit is cooling and heating, in order to ensure the reliability of the refrigerant flow, the air source heat pump unit includes a four-way valve 400, which is used to switch the refrigerant flow direction.

[0090] Specifically, the four-way valve 400 includes a first reversing port, which is connected to a third pipe 210. The third pipe 210 is connected to the exhaust port of the compressor 200 so that the refrigerant compressed by the compressor 200 can flow into the first reversing port through the third pipe 210.

[0091] The four-way valve 400 includes a second reversing port, which is connected to a second pipeline 111. The second pipeline 111 is connected to the indoor heat exchanger 100 so that the refrigerant flowing out of the compressor 200 flows through the second reversing port to the indoor heat exchanger 100 via the second pipeline 111, or the refrigerant flowing out of the indoor heat exchanger 100 flows back to the compressor 200 via the second pipeline 111 and the second reversing port.

[0092] The four-way valve 400 includes a third reversing port, which is connected to a fourth pipe 211. The fourth pipe 211 is connected to the return port of the compressor 200 so that the refrigerant in a low-temperature and low-pressure state flows back to the compressor 200 through the third reversing port via the fourth pipe 211.

[0093] The four-way valve 400 includes a fourth reversing port, which is connected to the end of the fifth pipeline 310 away from the outdoor heat exchanger 300, so that high-temperature and high-pressure refrigerant can flow from the fifth pipeline 310 to the outdoor heat exchanger 300 through the fourth reversing port, or low-temperature and low-pressure refrigerant can flow from the fifth pipeline 310 to the compressor 200 through the fourth reversing port.

[0094] The indoor heat exchanger 100, compressor 200, outdoor heat exchanger 300 and four-way valve 400 form a refrigerant circulation loop through pipelines. The refrigerant flows in the refrigerant circulation loop to cool or heat the indoor environment.

[0095] When the air source heat pump unit cools the indoor environment, the first and fourth reversing ports of the four-way valve 400 are connected, and the second and third reversing ports are connected. The refrigerant, after being compressed by the compressor 200, flows into the four-way valve 400 through the first reversing port via the third pipe 210, flows out through the fourth reversing port, and enters the outdoor heat exchanger 300 through the fourth connecting port via the fifth pipe 310. The outdoor heat exchanger 300 works as a condenser, where the refrigerant condenses and releases heat. After the heat release is complete, it flows out through the third connecting port, through the first pipe 110, and into the indoor heat exchanger 100 through the second connecting port. The indoor heat exchanger 100 works as an evaporator, where the refrigerant evaporates and absorbs heat to lower the indoor temperature. After the heat exchange is complete, it flows out through the first connecting port, through the second pipe 111, and into the four-way valve 400 through the second reversing port. Then, it flows out through the third reversing port, through the fourth pipe 211, and into the compressor 200 through the return port to complete the refrigeration cycle.

[0096] When the air source heat pump unit heats the indoor environment, the first and second reversing ports of the four-way valve 400 are connected, and the third and fourth reversing ports are connected. The refrigerant, compressed by the compressor 200, flows out from the exhaust port, through the third pipe 210, and into the four-way valve 400 through the first reversing port. It then flows out from the second reversing port, through the second pipe 111, and into the indoor heat exchanger 100 through the first connecting port. The indoor heat exchanger 100 functions as a condenser, and the refrigerant condenses in the condenser. Heat is released to increase the indoor temperature. After the heat release is completed, the refrigerant flows out from the second connection port, passes through the first pipe 110, and enters the outdoor heat exchanger 300 through the third connection port. The outdoor heat exchanger 300 works as an evaporator. The refrigerant evaporates and absorbs heat in the evaporator. After the heat exchange is completed, the refrigerant flows out from the fourth connection port, passes through the fifth pipe 310, and enters the four-way valve 400 through the fourth reversing liquid port. It then flows out from the third reversing liquid port, passes through the fourth pipe 211, and enters the compressor 200 through the return gas port to complete the heating cycle.

[0097] When the outdoor heat exchanger 300 operates as an evaporator, it absorbs heat from the air, causing its surface temperature to drop and making it prone to frost formation. Furthermore, during the defrosting process of the air source heat pump unit, the condensate produced on the surface of the outdoor heat exchanger 300 accumulates at the bottom due to gravity. Prolonged operation of the air source heat pump unit in a low-temperature environment can lead to ice buildup at the bottom of the outdoor heat exchanger 300, which is difficult to remove, resulting in a significant decrease in the heating efficiency of the air source heat pump unit. Additionally, because the outdoor heat exchanger 300 is relatively close to the compressor 200, the long-term accumulation of ice poses a risk of damaging the compressor 200.

[0098] Based on this, in this application, an antifreeze pipe 700 is installed at the bottom of the outdoor heat exchanger 300. When the air source heat pump unit is heating, the high-pressure refrigerant that is not throttled by the expansion valve 600 flows into the antifreeze pipe 700 to defrost the outdoor heat exchanger.

[0099] Specifically, such as Figures 1-3 As shown, the air source heat pump unit includes an antifreeze pipe 700, at least a portion of which is located at the bottom of the outdoor heat exchanger 300 for defrosting the outdoor heat exchanger 300.

[0100] The antifreeze pipe 700 is provided with an inlet end, which is connected to the first pipe 110 so that the refrigerant flows into the antifreeze pipe 700 from the inlet end through the first pipe 110; the inlet end is located on the side of the expansion valve 600 near the indoor heat exchanger.

[0101] The antifreeze pipe 700 is provided with an outlet end, which is connected to the first pipe 110 so that the refrigerant in the antifreeze pipe 700 flows back to the first pipe 110 through the outlet end; the outlet end is located on the side of the expansion valve 600 near the indoor heat exchanger.

[0102] It should be noted that the inlet end is located near the indoor heat exchanger 100, and the outlet end is located near the outdoor heat exchanger 300. The inlet end and the outlet end are respectively located between the indoor heat exchanger 100 and the expansion valve 600, so that the high-pressure refrigerant can flow into the antifreeze pipe 700.

[0103] like Figure 2 As shown, when the air source heat pump unit cools the indoor environment, the outdoor heat exchanger 300 acts as a condenser. The outdoor heat exchanger 300 does not need to be defrosted. The refrigerant in the outdoor heat exchanger 300 flows into the indoor heat exchanger through the first pipe 110 and does not need to flow through the antifreeze pipe 700.

[0104] like Figure 3 As shown, when the air source heat pump unit heats the indoor environment, the outdoor heat exchanger 300 acts as an evaporator. The outdoor heat exchanger 300 may frost up. The refrigerant in the indoor heat exchanger 100 is diverted, so that part of the refrigerant enters the antifreeze pipe 700 before flowing through the expansion valve 600 to defrost the outdoor heat exchanger 300; the other part of the refrigerant flows through the expansion valve 600 and is throttled by the expansion valve 600 before flowing into the outdoor heat exchanger 300 to absorb heat from the outdoor air.

[0105] In some embodiments, when the outdoor heat exchanger 300 is a finned heat exchanger, the antifreeze pipe 700 is located at the bottom of the finned heat exchanger, the antifreeze pipe 700 passes through the fins, and the antifreeze pipe 700 is arranged in parallel with the heat exchange pipe.

[0106] like Figures 1-3 As shown, the air source heat pump unit also includes a three-way valve 800, which is located at the connection between the inlet end of the antifreeze pipe 700 and the first pipe 110, and is used to connect or disconnect the antifreeze pipe 700 and the first pipe 110 and control the on / off state of the first pipe 110.

[0107] like Figure 4 As shown, the three-way valve 800 includes port A, which is connected to the first pipeline 110 and is located near the indoor heat exchanger 100.

[0108] The three-way valve 800 includes port B, which is connected to the first pipeline 110 and is located near the outdoor heat exchanger 300.

[0109] The three-way valve 800 includes a C port, which is connected to the inlet end of the antifreeze pipeline 700 and is used to cut off or connect the first pipeline 110 and the antifreeze pipeline 700.

[0110] When the air source heat pump unit cools the indoor environment, the outdoor heat exchanger 300 acts as a condenser. The outdoor heat exchanger 300 does not need to be defrosted. Port B and port A are connected, and port C is cut off. The refrigerant in the outdoor heat exchanger 300 flows through port B and port A in sequence and then flows into the indoor heat exchanger 100.

[0111] When the air source heat pump unit heats the indoor environment, the outdoor heat exchanger 300 acts as an evaporator. The outdoor heat exchanger 300 may frost over. Ports A and B are connected, and ports A and C are also connected, so that the refrigerant in the indoor heat exchanger 100 is split at the three-way valve 800. Part of the refrigerant flows through ports A and C and then into the antifreeze pipe 700, while the other part of the refrigerant flows through ports A and B and continues to flow along the first pipe 110. The refrigerant flowing into the antifreeze pipe 700 flows back to the first pipe 110 from the outlet end of the antifreeze pipe 700 and enters the outdoor heat exchanger 300 along the first pipe 110.

[0112] In some embodiments, the three-way valve 800 includes a valve core 803, which has an A port, a B port and a C port, wherein the B port and the C port are located on the same side of the valve core 803, and the A port is located on the other side of the valve core 803.

[0113] The three-way valve 800 includes a valve stem 802, which is inserted into the valve core 803 and is used to connect or disconnect port A and port B, as well as to connect or disconnect port A and port C.

[0114] It should be noted that in some embodiments, when port A is disconnected from port C, port A is connected to port B; when port A is disconnected from port B, port A is connected to port C.

[0115] The three-way valve 800 includes a drive motor 801, which drives the valve stem 802 to move, so as to connect or disconnect port A and port B, and to connect or disconnect port A and port C.

[0116] The air source heat pump unit includes a controller 1000, which is connected to a three-way valve 800 and is used to control the operation of the three-way valve 800.

[0117] The controller 1000 is configured to: when refrigerant flows from the outdoor heat exchanger 300 to the indoor heat exchanger 100, control the three-way valve 800 to connect the first pipeline 110 and disconnect the antifreeze pipeline 700 from the first pipeline 110; when refrigerant flows from the indoor heat exchanger 100 to the outdoor heat exchanger 300, control the three-way valve 800 to connect the antifreeze pipeline 700 from the first pipeline 110.

[0118] The controller 1000 is configured to: control port A to connect to port B to connect to the first pipeline 110; control port A to connect to port C to connect the antifreeze pipeline 700 to the first pipeline 110; control port B to disconnect the first pipeline 110; and control port C to disconnect the antifreeze pipeline 700 to the first pipeline 110.

[0119] It should be noted that the controller 1000 is electrically connected to the drive motor 801. The controller 1000 controls the operation of the three-way valve 800 by controlling the movement of the drive motor 801. This will not be elaborated further here.

[0120] When the valve opening of the three-way valve 800 is at the first opening degree, port A and port B are connected and port C is cut off; when the valve opening of the three-way valve 800 is at the second opening degree, port A and port C are connected and port B is cut off.

[0121] like Figure 5 and Figure 6 As shown, when the air source heat pump unit cools the indoor environment, the refrigerant flows from the outdoor heat exchanger 300 to the indoor heat exchanger 100. The outdoor heat exchanger 300 acts as a condenser, and the refrigerant condenses and releases heat in the condenser. The outdoor heat exchanger 300 will not frost. To avoid unnecessary heat loss, the A port of the three-way valve 800 is connected to the B port and the C port is cut off, so that all the refrigerant flows into the outdoor heat exchanger 300 through the first pipe 110.

[0122] That is, the controller 1000 is configured to control the three-way valve 800 to operate at the first opening degree when the refrigerant flows from the outdoor heat exchanger 300 to the indoor heat exchanger 100.

[0123] In some embodiments, the first opening is 0% to prevent refrigerant from entering the antifreeze pipe 700, so that all refrigerant flows into the first pipe 110, giving the air source heat pump unit a good cooling effect.

[0124] When the air source heat pump unit heats the indoor environment, the refrigerant flows from the indoor heat exchanger 100 to the outdoor heat exchanger 300. The outdoor heat exchanger 300 acts as an evaporator, where the refrigerant evaporates and absorbs heat. This can easily cause frost to form on the outdoor heat exchanger 300 pipes due to low temperatures. To prevent frost formation on the outdoor heat exchanger 300 pipes and its impact on heating performance, when the air source heat pump unit enters heating mode, the A and C ports of the three-way valve 800 are connected while the B port is cut off. This state is maintained for a period of time, allowing the refrigerant that has released heat through the indoor heat exchanger 100 to flow into the outdoor heat exchanger 300 through the antifreeze pipe 700. Although the refrigerant temperature decreases after releasing heat through the indoor heat exchanger 100, it still retains some heat. The residual heat of the high-pressure refrigerant can be used to defrost the outdoor heat exchanger 300, preventing frost from forming on the surface of the outdoor heat exchanger 300 pipes.

[0125] That is, the controller 1000 is configured such that when the refrigerant flows from the indoor heat exchanger 100 to the outdoor heat exchanger 300, the three-way valve 800 is first controlled to operate at the second opening degree for a first time tq.

[0126] When an air source heat pump unit heats the indoor environment, if the frosting status of the outdoor heat exchanger 300 is unknown, continuously allowing high-pressure refrigerant to enter the antifreeze pipe 700 for defrosting will cause unnecessary heat loss. Therefore, it is necessary to judge the degree of frosting on the outdoor heat exchanger 300 based on the outdoor ambient temperature Ta and the capillary temperature Te of the outdoor heat exchanger, and control the opening of the three-way valve 800 according to the judgment result, so as to prevent frost from forming on the surface of the outdoor heat exchanger 300 pipe while ensuring the heating effect of the air source heat pump unit.

[0127] That is, the controller is configured to determine the valve opening degree of the three-way valve 800 in real time based on the outdoor ambient temperature Ta and the capillary temperature Te of the outdoor heat exchanger 300.

[0128] The reference temperature Tc1 is calculated based on the real-time outdoor ambient temperature Ta. The frosting condition of the outdoor heat exchanger 300 pipe surface is determined based on the outdoor heat exchanger capillary temperature Te and the reference temperature Tc1. When the outdoor heat exchanger 300 capillary temperature Te is less than or equal to the reference temperature Tc1, it indicates that the outdoor heat exchanger 300 is frosted and needs to be defrosted. To do this, the A and C ports of the three-way valve 800 need to be connected while the B port is cut off, so that the high-pressure refrigerant flows into the antifreeze pipe 700. The high-pressure refrigerant has a certain amount of heat, and the residual heat of the high-pressure refrigerant is used to defrost the outdoor heat exchanger 300 to prevent frosting on the surface of the outdoor heat exchanger 300 pipe.

[0129] That is, the controller 1000 is further configured to: acquire the outdoor ambient temperature Ta and the capillary temperature Te of the outdoor heat exchanger 300 in real time, and obtain the reference temperature Tc1 based on the outdoor ambient temperature Ta; if the capillary temperature Te of the outdoor heat exchanger 300 is less than or equal to the reference temperature Tc1, then control the three-way valve 800 to operate at the second opening degree.

[0130] When the capillary temperature Te of the outdoor heat exchanger 300 is greater than the reference temperature Tc1, it indicates that the degree of frost on the surface of the outdoor heat exchanger 300 pipe is small or there is no frost on the surface of the outdoor heat exchanger 300 pipe. In this case, it is necessary to control the connection between port A and port B of the three-way valve 800 and the connection between port A and port C. Refrigerant can flow into the outdoor heat exchanger 300 through the first pipe 110 via ports A and B, or it can flow into the outdoor heat exchanger 300 through the antifreeze pipe 700 via ports A and C. It is necessary to determine the proportion of refrigerant flowing through ports A and C into the antifreeze pipe 700 based on the capillary temperature Te of the outdoor heat exchanger, so as to ensure that the appropriate proportion of refrigerant flows into the antifreeze pipe 700 according to the frost situation. The high-pressure refrigerant flowing into the antifreeze pipe 700 has a certain amount of heat. The residual heat of the high-pressure refrigerant is used to defrost the outdoor heat exchanger 300 to prevent frost from forming on the outdoor heat exchanger 300.

[0131] That is, the controller is configured to calculate the opening degree of the three-way valve 800 according to the opening degree formula if the capillary temperature Te of the outdoor heat exchanger 300 is greater than the reference temperature Tc1.

[0132] In some embodiments, the opening formula is as follows:

[0133] yi = e -kbTe (10% ≤ yi ≤ 90%)

[0134] Where yi is the valve opening degree of the three-way valve, kb is the correction coefficient, the value of which is related to the outdoor ambient temperature Ta; Te is the capillary temperature of the outdoor heat exchanger, which is negatively correlated with the valve opening degree.

[0135] It should be noted that when the air source heat pump unit heats the indoor environment, the outdoor ambient temperature Ta and the outdoor heat exchanger capillary temperature Te are constantly changing. Since whether the surface of the outdoor heat exchanger 300 pipe is frosted depends on these two changing values, if the degree of frost on the outdoor heat exchanger 300 pipe is small or there is no frost on the surface at the current moment, it is necessary to continue to obtain the outdoor ambient temperature Ta and the outdoor heat exchanger capillary temperature Te in real time to determine the frost status of the outdoor heat exchanger 300 pipe.

[0136] If the duration for which the capillary temperature Te of the outdoor heat exchanger 300 is less than or equal to the reference temperature Tc1 is greater than the second time tj, it indicates that there is still a lot of frost on the surface of the pipe of the outdoor heat exchanger 300. It is necessary to control the three-way valve 800 to connect port A and port C and cut off port B, so that the air source heat pump unit enters the defrosting mode, allowing the high-pressure refrigerant to flow into the antifreeze pipe 700, and use the residual heat of the high-pressure refrigerant to defrost the outdoor heat exchanger.

[0137] That is, the controller is configured to: calculate the duration of the outdoor heat exchanger capillary temperature Te being less than or equal to the reference temperature Tc1; if the duration is greater than the second time tj, the air source heat pump unit enters the defrost mode and controls the opening degree of the three-way valve 800 to the second opening degree.

[0138] It should be noted that if the duration for which the current outdoor heat exchanger capillary temperature Te is less than or equal to the reference temperature Tc1 is less than the second time tj, it only means that the frost on the surface of the outdoor heat exchanger 300 pipe is not very severe at the current time. It is necessary to continue to obtain the outdoor ambient temperature Ta and the outdoor heat exchanger capillary temperature Te in real time, and to continue to judge the frost on the surface of the outdoor heat exchanger 300 pipe at the next moment based on the outdoor ambient temperature Ta and the outdoor heat exchanger capillary temperature Te.

[0139] That is, the controller is configured to: if the duration is less than the second time tj, then determine the opening degree of the three-way valve in real time based on the outdoor ambient temperature Ta and the outdoor heat exchanger capillary temperature Te.

[0140] In some embodiments, the outdoor ambient temperature Ta can be divided into intervals, and a reference temperature Tc1 can be calculated based on the outdoor ambient temperature Ta of each interval. The reference temperature Tc1 of each interval is compared with the outdoor heat exchanger capillary temperature Te, so that the controller 1000 can more accurately determine the valve opening of the three-way valve 800 based on the outdoor capillary temperature Te and the reference temperature Tc1.

[0141] Specifically, if the outdoor ambient temperature Ta is less than or equal to the first critical value Ta1, then the outdoor ambient temperature Ta is in the first temperature range Re1. The reference temperature Tc1 of the first range Re1 is calculated based on the first adjustment value K1. If the outdoor ambient temperature Ta is greater than the first critical value Ta1 and less than or equal to the second critical value Ta2, then the outdoor ambient temperature Ta is in the second temperature range Re2. The reference temperature Tc1 of the second range Re2 is calculated based on the second adjustment value K2 and the first coefficient dj1. If the outdoor ambient temperature Ta is greater than the second critical value Ta2 and less than or equal to the third critical value Ta3, then the outdoor ambient temperature Ta is in the third temperature range Re3. The reference temperature Tc1 of the third range Re3 is calculated based on the third adjustment value K3 and the second coefficient dj2. If the outdoor ambient temperature Ta is greater than the third critical value Ta3 and less than or equal to the fourth critical value Ta4, then the outdoor ambient temperature Ta is in the fourth temperature range Re4. The reference temperature Tc1 of the fourth range Re4 is calculated based on the fourth adjustment value K4 and the third coefficient dj3. Wherein, the first critical value Ta1 is less than the second critical value Ta2, less than the third critical value Ta3, and less than the fourth critical value Ta4.

[0142] After defrosting, to avoid unnecessary heat loss, the three-way valve 800A port is connected to port B and port C is cut off, and this state is maintained for a period of time, so that all the refrigerant enters the outdoor heat exchanger 300 through the first pipe 110.

[0143] That is, the controller 1000 is further configured to: when the capillary temperature Te of the outdoor heat exchanger 300 reaches the set value, the air source heat pump unit exits the defrost mode and controls the three-way valve 800 to operate at the first opening degree.

[0144] When the air source heat pump unit defrosts the outdoor heat exchanger 300, the condensate generated during defrosting mode will accumulate in the antifreeze pipe 700 due to gravity. When the air source heat pump unit heats the indoor environment, the outdoor heat exchanger 300 acts as an evaporator, and the refrigerant evaporates and absorbs heat in the evaporator. This causes the condensate accumulated in the antifreeze pipe 700 to freeze at the bottom of the antifreeze pipe 700 of the outdoor heat exchanger 300 in a low-temperature environment. It is necessary to determine whether the antifreeze pipe 700 has frozen based on the operation time of the defrosting mode.

[0145] That is, the controller is configured to obtain the defrost mode running time after the air source heat pump unit exits the defrost mode.

[0146] The defrosting mode has a short operating time, and usually produces less condensate in the antifreeze pipe 700 at the bottom of the outdoor heat exchanger 300. The antifreeze pipe 700 at the bottom of the outdoor heat exchanger 300 is not easy to freeze. However, if the outdoor heat exchanger 300 is working as an evaporator, the condensate may freeze, and some refrigerant still needs to be used to defrost the outdoor heat exchanger 300. Therefore, the frosting condition on the surface of the pipes of the outdoor heat exchanger 300 is judged based on the outdoor ambient temperature Ta and the capillary temperature Te of the outdoor heat exchanger.

[0147] That is, the controller is configured to: if the defrost mode running time is less than or equal to the first reference value, then determine the opening degree of the three-way valve 800 in real time based on the outdoor ambient temperature Ta and the outdoor heat exchanger capillary temperature Te.

[0148] The defrosting mode operates for a long time, and the outdoor heat exchanger 300 usually produces a lot of condensate during defrosting. The condensate tends to accumulate at the bottom of the outdoor heat exchanger 300, which may cause the antifreeze pipe 700 to freeze. Therefore, it is necessary to control the three-way valve 800 to operate with port A and port C connected and port B cut off for a period of time, so that the high-pressure refrigerant flowing from the indoor heat exchanger 100 enters the antifreeze pipe 700. The high-pressure refrigerant passing through the antifreeze pipe 700 has a certain amount of heat to prevent the antifreeze pipe 700 from freezing.

[0149] That is, the controller is configured to: if the defrosting mode running time is greater than the first reference value, then control the three-way valve 800 to work at the second opening for a third time, and then determine the opening of the three-way valve 800 in real time based on the outdoor ambient temperature Ta and the capillary temperature Te of the outdoor heat exchanger 300.

[0150] In some embodiments, the first reference value is 5 minutes. If the defrosting mode runs for too short a time, the defrosting of the surface of the outdoor heat exchanger 300 pipe will be incomplete. If the defrosting mode runs for too long a time, it will affect the original operation of the air source heat pump unit.

[0151] If the antifreeze pipe 700 needs to be antifreeze operated, the controller 1000 needs to determine the antifreeze operation time based on the defrost mode operation time to prevent unnecessary heat loss when the air source heat pump unit heats the indoor environment.

[0152] That is, the controller 1000 is further configured to calculate the third time based on the running time of the defrost mode.

[0153] It should be noted that the third time is the running time of the anti-freeze operation.

[0154] In some embodiments, the third time interval can be divided according to the running time of the defrost mode to achieve precise defrosting.

[0155] Specifically, such as Figure 7 As shown, the defrost mode can be divided into four intervals based on its running time: FA_1 interval, FA_2 interval, FA_3 interval, and FA_4 interval. If the defrost mode running time is greater than the first reference value and less than the first boundary value tdf1, and the defrost mode running time belongs to the FA_1 interval, then the antifreeze operation running time is set to the first partition time tr1. If the defrost mode running time is greater than the first boundary value tdf1 and less than the second boundary value tdf2, and the defrost mode running time belongs to the FA_2 interval, then the antifreeze operation running time is set to the second partition time tr2. If the defrost mode running time is greater than the second boundary value tdf2 and less than the third boundary value tdf3, and the defrost mode running time belongs to the FA_3 interval, then the antifreeze operation running time is set to the third partition time tr3. If the defrost mode running time is greater than the third boundary value tdf3, and the defrost mode running time belongs to the FA_4 interval, then the antifreeze operation running time is set to the fourth partition time tr4. The third boundary value tdf3 is greater than the second boundary value tdf2, greater than the first boundary value tdf1, and greater than the first reference value. That is, the fourth partition time tr4 is greater than the third partition time tr3, greater than the second partition time tr2, and greater than the first partition time tr1.

[0156] The air source heat pump unit includes a one-way valve 900, which is used to control the one-way flow of refrigerant; the one-way valve 900 is connected to the controller 1000.

[0157] The controller 1000 is configured to: control the check valve 900 to cut off the antifreeze pipe 700 when the refrigerant flows from the outdoor heat exchanger 300 to the indoor heat exchanger 100; and control the check valve 900 to connect the antifreeze pipe 700 when the refrigerant flows from the indoor heat exchanger 100 to the outdoor heat exchanger 300.

[0158] When the air source heat pump unit cools the indoor environment, the controller 1000 controls the one-way valve 900 to cut off the antifreeze pipe 700 to prevent refrigerant from flowing back into the antifreeze pipe 700, which would cause refrigerant to deposit in the antifreeze pipe 700 and affect the cooling or heating effect of the air source heat pump unit. When the air source heat pump unit heats the indoor environment, the controller 1000 controls the one-way valve 900 to connect the antifreeze pipe 700 so that the refrigerant entering the antifreeze pipe 700 can enter the outdoor heat exchanger 300 through the first pipe 110.

[0159] In some embodiments, the check valve 900 is located near the outlet end of the antifreeze line 700.

[0160] When the air source heat pump unit is cooling the indoor environment, the controller 1000 controls the three-way valve 800 to operate at the first opening degree, so that the refrigerant enters the outdoor heat exchanger 300 through the first pipeline 110.

[0161] When the air source heat pump unit is heating the indoor environment, initially, upon unit startup, the controller 1000 controls the three-way valve 800 to operate at its second opening degree. This allows the refrigerant to pass through the antifreeze pipe 700, then through the expansion valve 600 for throttling, before entering the outdoor heat exchanger 300. After the controller 1000 controls the three-way valve 800 to operate at the second opening degree for a period of time tq, the controller acquires the outdoor ambient temperature Ta and the outdoor heat exchanger capillary temperature Te. The outdoor ambient temperature Ta is then divided into intervals, and a reference temperature Tc1 is calculated for each interval. Based on the outdoor heat exchanger capillary temperature Te and the reference temperature Tc1, the controller determines the frost condition on the surface of the outdoor heat exchanger 300 pipes. If the outdoor heat exchanger capillary temperature Te is less than or equal to the reference temperature Tc1, the controller 1000 calculates the opening degree of the three-way valve 800 according to the opening formula, and the three-way valve 800 operates at the opening degree obtained from this formula. After a period of operation, it is necessary to continue to judge the frosting status of the outdoor heat exchanger 300 pipeline based on the outdoor ambient temperature Ta and the outdoor capillary temperature Te. If the outdoor heat exchanger capillary temperature Te is greater than the reference temperature Tc1, the controller controls the three-way valve to operate at the second opening degree. If the duration for which the outdoor heat exchanger capillary temperature Te is less than or equal to the reference temperature Tc1 is greater than the second time tj, the controller 1000 controls the unit to enter the defrosting mode. If the duration for which the outdoor heat exchanger capillary temperature Te is less than or equal to the reference temperature Tc1 is less than the second time tj, it is necessary to continue to judge the frosting status of the outdoor heat exchanger 300 pipeline based on the outdoor ambient temperature Ta and the outdoor capillary temperature Te. After the defrosting mode is activated, the controller 1000 controls the three-way valve 800 to operate at the second opening degree until the outdoor heat exchanger capillary temperature Te reaches the set value. At this point, the unit's defrosting mode ends, and the unit exits the defrosting mode.

[0162] After the air source heat pump unit exits defrost mode, the controller 1000 controls the three-way valve 800 to operate at the first opening degree for a first time tq. Then, based on the defrost mode operating time, the controller determines the valve opening degree of the three-way valve 800. If the defrost mode operating time is greater than the first reference value, the controller 1000 controls the three-way valve 800 to operate at the second opening degree. The duration of the three-way valve 800 operating at the second opening degree is divided into intervals based on the defrost mode operating time. The longer the defrost mode operating time within an interval, the greater the opening degree of the three-way valve 800. The longer the second opening operation time, the more the controller 1000 needs to continue to judge the frosting condition of the outdoor heat exchanger 300 pipeline based on the outdoor ambient temperature Ta and the outdoor capillary temperature Te after the second opening operation time of the three-way valve 800 ends, and control the opening of the three-way valve 800 according to the frosting condition. If the defrosting mode operation time is less than or equal to the first reference value, it is necessary to continue to judge the frosting condition of the outdoor heat exchanger 300 pipeline based on the outdoor ambient temperature Ta and the outdoor capillary temperature Te, and control the opening of the three-way valve 800 according to the frosting condition.

[0163] like Figures 8-10 As shown, in some embodiments of this application, the air source heat pump unit includes a subcooling section 500, which is located at the bottom of the outdoor heat exchanger 300. An antifreeze pipe 700 is located at the bottom of the subcooling section 500. The subcooling section 500 is used to reduce the temperature of the refrigerant flowing through the subcooling section 500.

[0164] The subcooling section 500 includes a fifth connecting port, which is connected to a sixth pipe 311. The subcooling section 500 is connected to the outdoor heat exchanger 300 through the sixth pipe 311. When the outdoor heat exchanger 300 operates as a condenser, refrigerant flows out of the outdoor heat exchanger 300 and into the subcooling section 500 through the fifth connecting port; when the outdoor heat exchanger 300 operates as an evaporator, refrigerant flows out of the subcooling section 500 through the fifth connecting port and into the outdoor heat exchanger 300.

[0165] The subcooling section 500 includes a sixth connecting port, which is connected to a seventh pipe 510. The subcooling section 500 is connected to the first pipe 110 through the seventh pipe 510. When the outdoor heat exchanger 300 operates as a condenser, the refrigerant flows out of the subcooling section 500 through the sixth connecting port and enters the first pipe 110. When the outdoor heat exchanger 300 operates as an evaporator, the refrigerant flowing from the first pipe 110 or the antifreeze pipe 700 flows into the subcooling section 500 through the sixth connecting port.

[0166] like Figure 9As shown, when the air source heat pump unit cools the indoor environment, the outdoor heat exchanger 300 acts as a condenser. After the refrigerant releases heat in the condenser, it enters the subcooling section 500 through the sixth pipe 311 for subcooling. The subcooled refrigerant flows out through the seventh pipe 510. The B and A ports of the three-way valve 800 at the inlet end of the antifreeze pipe 700 are connected, while the C port is cut off. The refrigerant from the seventh pipe 510 flows out through the B and A ports of the three-way valve 800, passes through the first pipe 110, and enters the indoor heat exchanger 100. After subcooling, the refrigerant flows through the seventh pipe 510 into the first pipe 110, and then through the first pipe 110 into the indoor heat exchanger 100.

[0167] like Figure 10 As shown, when the air source heat pump unit heats the indoor environment, the outdoor heat exchanger 300 acts as the evaporator. The A and B ports of the three-way valve 800 at the inlet end of the antifreeze pipe 700 are connected, and the A and C ports of the three-way valve 800 are also connected. After the refrigerant evaporates and absorbs heat in the evaporator, a portion of the refrigerant passes through the first pipe 110 and enters the antifreeze pipe 700 through the A and C ports of the three-way valve 800. It then flows out from the outlet end of the antifreeze pipe 700, passes through the first pipe 110, enters the subcooling section 500 for subcooling, and then enters the outdoor heat exchanger 300. Another portion of the refrigerant passes through the A and B ports of the three-way valve 800, passes through the first pipe 100, enters the subcooling section 500 for subcooling, and then enters the outdoor heat exchanger 300.

[0168] The aforementioned air source heat pump unit incorporates an antifreeze pipe 700 at the bottom of the outdoor heat exchanger 300, a traditional air source heat pump unit. A three-way valve 800 is installed at the inlet of the antifreeze pipe 700, and a one-way valve 900 is installed at the outlet of the antifreeze pipe 700. The controller 1000 controls the operation of the three-way valve 800 and the one-way valve 900. The control logic optimizes the operation of the three-way valve 800 with different valve openings when the air source heat pump unit is cooling or heating the indoor environment. This achieves differentiated flow path design for the refrigerant when flowing into or out of the outdoor heat exchanger 300, effectively solving the problem of air source heat pump unit operation reliability caused by ice formation at the bottom of the outdoor heat exchanger 300 and significantly improving the heating and cooling performance of the air source heat pump unit.

[0169] Compared to traditional air source heat pump units, the aforementioned air source heat pump unit's circulation system features a differentiated flow path design for refrigerant flowing into or out of the outdoor heat exchanger 300. This significantly improves the cooling performance of the air source heat pump unit when cooling the indoor environment. Furthermore, by incorporating anti-freeze piping 700 and a three-way valve 800, the air source heat pump unit can control the three-way valve 800 to operate at different opening degrees based on the unit's operating status and real-time monitoring data. This allows for different proportions of refrigerant flow when flowing into or out of the outdoor heat exchanger 300, ensuring that the air source heat pump unit effectively improves its heating performance while meeting the anti-freezing requirements of the bottom of the outdoor heat exchanger 300.

[0170] 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.

[0171] 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. An air source heat pump unit, characterized in that, include: An indoor heat exchanger, the indoor heat exchanger including a first connection port and a second connection port; A four-way valve is used to switch the direction of refrigerant flow; the four-way valve includes a first reversing liquid port, a second reversing liquid port, a third reversing liquid port and a fourth reversing liquid port, wherein the second reversing liquid port is connected to the first connecting port; A compressor is used to drive the flow of refrigerant; the inlet end of the compressor is connected to the third reversing liquid port, and the outlet end of the compressor is connected to the first reversing liquid port. An outdoor heat exchanger includes a third connection port and a fourth connection port, the fourth connection port being connected to the fourth diversion liquid port; the third connection port is connected to the second connection port through a first pipeline. An expansion valve, located on the first pipeline, is used to throttle the refrigerant flowing into the outdoor heat exchanger; An antifreeze pipeline, at least a portion of which is located at the bottom of the outdoor heat exchanger; the inlet and outlet ends of the antifreeze pipeline are respectively connected to the first pipeline and located on the side of the expansion valve near the indoor heat exchanger; A three-way valve is located at the connection point between the inlet end of the antifreeze pipeline and the first pipeline, and is used to connect or disconnect the antifreeze pipeline and the first pipeline, as well as to control the on / off state of the first pipeline. The controller, which is connected to the three-way valve, is configured to: When the refrigerant flows from the outdoor heat exchanger to the indoor heat exchanger, the three-way valve is controlled to connect the first pipeline and disconnect the antifreeze pipeline from the first pipeline; When the refrigerant flows from the indoor heat exchanger to the outdoor heat exchanger, the three-way valve is controlled to connect the antifreeze pipeline to the first pipeline.

2. The air source heat pump unit according to claim 1, characterized in that, The three-way valve includes port A, port B, and port C. Port A is located near the indoor heat exchanger, and port B is located near the outdoor heat exchanger. Ports A and B are respectively connected to the first pipeline, and port C is connected to the inlet end of the antifreeze pipeline. The controller is configured to: control the connection between port A and port B to connect the first pipeline; control the connection between port A and port C to connect the antifreeze pipeline and the first pipeline; control the disconnection of port B to disconnect the first pipeline; and control the disconnection of port C to disconnect the antifreeze pipeline and the first pipeline.

3. The air source heat pump unit according to claim 2, characterized in that, When the valve opening of the three-way valve is at the first opening degree, port A is connected to port B and port C is cut off; when the valve opening of the three-way valve is at the second opening degree, port A is connected to port C and port B is cut off. The controller is further configured to control the three-way valve to operate at a first opening degree when the refrigerant flows from the outdoor heat exchanger to the indoor heat exchanger. When the refrigerant flows from the indoor heat exchanger to the outdoor heat exchanger, the three-way valve is controlled to operate at the second opening degree for a first time tq, and then the valve opening degree of the three-way valve is determined in real time according to the outdoor ambient temperature Ta and the capillary temperature Te of the outdoor heat exchanger.

4. The air source heat pump unit according to claim 3, characterized in that, The controller is further configured to: acquire the outdoor ambient temperature Ta and the outdoor heat exchanger capillary temperature Te, and obtain a reference temperature Tc1 based on the outdoor ambient temperature Ta; If the capillary temperature Te of the outdoor heat exchanger is less than or equal to the reference temperature Tc1, then the three-way valve is controlled to operate at the second opening degree. If the capillary temperature Te of the outdoor heat exchanger is greater than the reference temperature Tc 1, then the opening degree of the three-way valve is calculated according to the opening degree formula.

5. The air source heat pump unit according to claim 4, characterized in that, The controller is further configured to: The outdoor ambient temperature Ta and the outdoor heat exchanger capillary temperature Te are acquired in real time to determine the opening degree of the three-way valve in real time. Calculate the duration of the state in which the capillary temperature Te of the outdoor heat exchanger is less than or equal to the reference temperature Tc 1; If the duration is greater than the second time tj, the valve opening of the three-way valve is controlled to the second opening, and the air source heat pump unit enters the defrosting mode. If the duration is less than the second time tj, the opening degree of the three-way valve is determined in real time based on the outdoor ambient temperature Ta and the outdoor heat exchanger capillary temperature Te.

6. The air source heat pump unit according to claim 5, characterized in that, The controller is further configured to: when the capillary temperature Te of the outdoor heat exchanger reaches a set value, control the three-way valve to operate at a first opening degree, and the air source heat pump unit exits the defrosting mode.

7. The air source heat pump unit according to claim 6, characterized in that, The controller is further configured to: obtain the running time of the defrosting mode after the air source heat pump unit exits the defrosting mode; If the defrosting mode running time is less than or equal to the first reference value, the opening degree of the three-way valve is determined in real time based on the outdoor ambient temperature Ta and the outdoor heat exchanger capillary temperature Te. If the defrosting mode operation time is greater than the first reference value, the three-way valve is controlled to operate at the second opening degree for a third time. Then, the opening degree of the three-way valve is determined in real time based on the outdoor ambient temperature Ta and the outdoor heat exchanger capillary temperature Te.

8. The air source heat pump unit according to claim 7, characterized in that, The operation time of the defrosting mode is positively correlated with the third time. The controller is further configured to calculate the third time based on the operating time of the defrosting mode.

9. The air source heat pump unit according to claim 1, characterized in that, The antifreeze pipeline is equipped with a one-way valve, which is connected to the controller. The controller is further configured to: control the one-way valve to cut off the antifreeze pipeline when the refrigerant flows from the outdoor heat exchanger to the indoor heat exchanger; and control the one-way valve to connect the antifreeze pipeline when the refrigerant flows from the indoor heat exchanger to the outdoor heat exchanger.

10. An air source heat pump unit, characterized in that, include: An indoor heat exchanger, the indoor heat exchanger including a first connection port and a second connection port; A four-way valve is used to switch the direction of refrigerant flow; the four-way valve includes a first reversing liquid port, a second reversing liquid port, a third reversing liquid port and a fourth reversing liquid port, wherein the second reversing liquid port is connected to the first connecting port; A compressor is used to drive the flow of refrigerant; the inlet end of the compressor is connected to the third reversing liquid port, and the outlet end of the compressor is connected to the first reversing liquid port. An outdoor heat exchanger includes a third connection port and a fourth connection port, the fourth connection port being connected to the fourth diversion liquid port; the third connection port is connected to the second connection port through a first pipeline. An expansion valve, located on the first pipeline, is used to throttle the refrigerant flowing into the outdoor heat exchanger; An antifreeze pipeline, at least a portion of which is located at the bottom of the outdoor heat exchanger; the inlet and outlet ends of the antifreeze pipeline are respectively connected to the first pipeline and located on the side of the expansion valve near the indoor heat exchanger; A three-way valve, comprising port A, port B and port C, wherein port A and port B are respectively connected to the first pipeline, and port C is connected to the inlet end of the antifreeze pipeline; The controller, which is connected to the three-way valve, is configured to: When the refrigerant flows from the outdoor heat exchanger to the indoor heat exchanger, the connection between port A and port B is controlled, and port C is cut off. When the refrigerant flows from the indoor heat exchanger to the outdoor heat exchanger, the A port is first connected to the C port and the B port is disconnected. After a period of time, the status of the A port, the B port and the C port are judged in real time based on the outdoor ambient temperature Ta and the outdoor heat exchanger capillary temperature Te.

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