Air conditioner

Abstract

The air conditioner comprises a first pipeline, a second pipeline and a third pipeline, the head end of the first pipeline is connected with an exhaust port through a first electromagnetic valve, the head end of the second pipeline is connected with the exhaust port through a second electromagnetic valve, and the tail end of the first pipeline and the tail end of the second pipeline are both used for being connected with the head end of the third pipeline. The tail end of the third pipeline is connected with the exhaust port through a third electromagnetic valve; a first expansion valve, a second expansion valve and a third expansion valve; the first end of the fourth electromagnetic valve is connected with the third electromagnetic valve and the tail end of the third pipeline, the second end of the fourth electromagnetic valve is connected with the first end of the fifth electromagnetic valve, the first end of the seventh electromagnetic valve and the air inlet, and the first end of the sixth electromagnetic valve is connected with the first electromagnetic valve; and the second end of the sixth electromagnetic valve is connected with the head end of the first pipeline and the second end of the seventh electromagnetic valve. By the adoption of the air conditioner, the problem that the refrigerating or heating capacity is insufficient or excessive due to the fact that a refrigerant heats the water tank firstly can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioners, and more particularly to an air conditioner. Background Art

[0002] In related technologies, existing air conditioners adopt a solution of adding a water tank to the refrigeration system to achieve the function of preparing domestic hot water while the air conditioner is operating in a refrigeration or heating mode. However, after the refrigerant is discharged from the compressor, regardless of the mode of the air conditioner, it will first pass through the water tank to heat the water in the tank. As a result, the air conditioner may have problems such as insufficient or excessive refrigeration or heating capacity. Summary of the Invention

[0003] The present invention aims to at least solve one of the technical problems existing in the prior art. For this purpose, an object of the present invention is to provide an air conditioner. By using this air conditioner, the flow direction of the refrigerant discharged from the compressor exhaust port can be changed according to different operating modes, so as to avoid the problems of insufficient or excessive refrigeration or heating capacity caused by the refrigerant heating the water tank first while the air conditioner has multiple operating modes.

[0004] To solve the above problems, an embodiment of the first aspect of the present invention provides an air conditioner, comprising: a water tank for storing domestic water; a first heat exchanger located outdoors for exchanging heat with the circulating refrigerant; a second heat exchanger connected to the water tank for exchanging heat with the domestic water; a third heat exchanger located indoors for adjusting the indoor temperature; a compressor having an exhaust port and an intake port; a first pipeline, a second pipeline and a third pipeline, wherein the head end of the first pipeline is connected to the exhaust port through a first solenoid valve, the head end of the second pipeline is connected to the exhaust port through a second solenoid valve, the tail ends of the first pipeline and the second pipeline are both used for connecting to the head end of the third pipeline, the tail end of the third pipeline is connected to the exhaust port through a third solenoid valve, the first heat exchanger is located on the first pipeline, the second heat exchanger is located on the second pipeline, and the third heat exchanger is located on the third pipeline; a first expansion valve, a second expansion valve and a third expansion valve, the first expansion valve is arranged on the first pipeline, the second expansion valve is arranged on the second pipeline, and the third expansion valve is arranged on the third pipeline; a fourth solenoid valve, a fifth solenoid valve, a sixth solenoid valve and a seventh solenoid valve, a first end of the fourth solenoid valve is connected to the third solenoid valve and the tail end of the third pipeline, a second end of the fourth solenoid valve is connected to a first end of the fifth solenoid valve, a first end of the seventh solenoid valve and the intake port, a first end of the sixth solenoid valve is connected to the first solenoid valve, and a second end of the sixth solenoid valve is connected to the head end of the first pipeline and a second end of the seventh solenoid valve; a controller configured to control the conduction states of each solenoid valve and each expansion valve according to the operating mode of the air conditioner.

[0005] For the air conditioner according to the embodiment of the present invention, three heat exchangers are respectively arranged on different pipelines, and seven solenoid valves are arranged between each pipeline and the exhaust port of the compressor to adjust the refrigerant flow direction. Thus, when the compressor discharges the refrigerant, it is no longer only that the refrigerant first passes through the water tank preferentially, but the conduction states of each solenoid valve and each expansion valve are controlled based on the operating mode of the air conditioner, so as to selectively control the refrigerant discharged from the exhaust port to enter the first pipeline, the second pipeline and / or the third pipeline, thereby while realizing that the air conditioner has a variety of different operating modes, avoiding the problem of insufficient or excessive cooling or heating capacity caused by the refrigerant heating the water tank first.

[0006] In some embodiments, for controlling the conduction states of each solenoid valve and each expansion valve according to the operating mode of the air conditioner, the controller is specifically configured to: when the operating mode is the simultaneous refrigeration and hot water production full heat recovery mode, control both the second solenoid valve and the fourth solenoid valve to be open, and control the first solenoid valve, the third solenoid valve, the fifth solenoid valve, the sixth solenoid valve, and the seventh solenoid valve to be closed, and control the first expansion valve to be closed, the second expansion valve to be conductive, and the third expansion valve to be conductive.

[0007] The above technical solution has the following advantages or beneficial effects: By controlling the conduction states of three expansion valves and seven solenoid valves, the full recovery of waste heat is achieved, meeting the user's hot water production requirements.

[0008] In some embodiments, for controlling the conduction states of each solenoid valve and each expansion valve according to the operating mode of the air conditioner, the controller is specifically configured to: when the operating mode is the simultaneous refrigeration and hot water production partial heat recovery mode, control the first solenoid valve, the second solenoid valve, the fourth solenoid valve, and the sixth solenoid valve to be open, and control the third solenoid valve, the fifth solenoid valve, and the seventh solenoid valve to be closed, and control the first expansion valve, the second expansion valve, and the third expansion valve to be conductive.

[0009] The above technical solution has the following advantages or beneficial effects: By controlling the conduction states of three expansion valves and seven solenoid valves, partial recovery of waste heat is achieved during refrigeration, improving the overall energy utilization rate of the air conditioning system, reducing the power consumption of the air conditioner, and thus achieving the purpose of saving electricity costs.

[0010] In some embodiments, the controller is further configured to: when the outdoor ambient temperature is within the normal operating range of the compressor, and the heat exchange temperature of the third heat exchanger is greater than the first preset temperature, and the shutdown duration of the compressor reaches the preset duration, control the compressor to start so that the air conditioner operates in the refrigeration mode; when the outdoor ambient temperature is within the normal operating range of the compressor, and the domestic water temperature is lower than the second preset temperature, and the shutdown duration of the compressor reaches the preset duration, control the compressor to start so that the air conditioner operates in the hot water production mode, where the hot water production mode includes the hot water production full heat recovery mode and the hot water production partial heat recovery mode; when the outdoor ambient temperature is within the normal operating range of the compressor, and the heat exchange temperature of the third heat exchanger is greater than the first preset temperature, and the domestic water temperature is lower than the second preset temperature, and the shutdown duration of the compressor reaches the preset duration, control the compressor to start so that the air conditioner operates in the simultaneous refrigeration and hot water production mode.

[0011] The above technical solution has the following advantages or beneficial effects: By the above different compressor starting conditions, the operating mode of the air conditioner can be accurately determined, effectively meeting the user's usage requirements and improving the intelligence of air conditioner use.

[0012] In some embodiments, after controlling the start of the compressor, the controller is further configured to: determine a first temperature difference between the domestic water temperature and the target water temperature, and determine a second temperature difference between the heat exchange temperature of the third heat exchanger and the target heat exchange temperature; control the change range of the operating frequency of the compressor according to the first temperature difference and the second temperature difference.

[0013] The above technical solution has the following advantages or beneficial effects: Determine the refrigeration demand and the domestic hot water demand through the first temperature difference and the second temperature difference, so as to dynamically adjust the change range of the operating frequency of the compressor through the refrigeration demand and the domestic hot water demand, thereby being able to balance the refrigeration and domestic hot water demands of the air conditioner and improve the overall efficiency of the system and the user experience.

[0014] In some embodiments, when controlling the first expansion valve in the domestic hot water partial heat recovery mode, the controller is further configured to: determine a third temperature difference between the coil temperature of the first heat exchanger and the outdoor ambient temperature; determine a first opening increment of the first expansion valve according to the third temperature difference; adjust the opening of the first expansion valve according to the first opening increment.

[0015] The above technical solution has the following advantages or beneficial effects: Determine the first opening increment of the second expansion valve according to the magnitude of the third temperature difference, so that the superheat at the outlet of the first heat exchanger meets the requirements.

[0016] In some embodiments, when controlling the second expansion valve in the domestic hot water mode, the controller is further configured to: obtain the condensation temperature of the refrigerant, and determine a fourth temperature difference between the condensation temperature and the domestic water temperature; determine a second opening increment of the second expansion valve according to the domestic water temperature and the fourth temperature difference; adjust the opening of the second expansion valve according to the second opening increment.

[0017] The above technical solution has the following advantages or beneficial effects: Determine the second opening increment of the second expansion valve according to the magnitude of the fourth temperature difference and the domestic water temperature, so that the superheat at the outlet of the second heat exchanger meets the requirements, achieving the purpose of heating the domestic water.

[0018] In some embodiments, when controlling the third expansion valve in the simultaneous refrigeration and hot water heating mode, the controller is further configured to: obtain the liquid pipe temperature of the third heat exchanger, the exhaust gas temperature of the compressor, and the inlet water temperature of the third heat exchanger; determine a fifth temperature difference between the inlet water temperature and the liquid pipe temperature; determine a third opening increment of the third expansion valve according to the exhaust gas temperature and the fifth temperature difference; and adjust the opening of the third expansion valve according to the third opening increment.

[0019] The above technical solution has the following advantages or beneficial effects: By changing the superheat degree at the outlet of the third heat exchanger according to the magnitude of the fifth temperature difference, so that the superheat degree at the outlet of the third heat exchanger meets the requirements, and by changing the low-pressure pressure of the refrigeration system through the third opening increment to balance the low-pressure pressure of the refrigeration system.

[0020] In some embodiments, the air conditioner further includes an outdoor fan, and the controller is further configured to: control the outdoor fan to close in the full heat recovery mode of hot water heating; in the partial heat recovery mode of hot water heating, determine a sixth temperature difference between the condensation temperature of the refrigerant and the coil temperature of the first heat exchanger, and control the rotation speed of the outdoor fan according to the sixth temperature difference.

[0021] The above technical solution has the following advantages or beneficial effects: By controlling the rotation speed of the outdoor fan according to the sixth temperature difference between the condensation temperature of the refrigerant and the coil temperature of the first heat exchanger, the rotation speed of the outdoor fan can be accurately controlled, effectively solving the problem of indoor ventilation and improving the indoor air quality.

[0022] In some embodiments, for controlling the rotation speed of the outdoor fan according to the sixth temperature difference, the controller is specifically configured to: if the sixth temperature difference is higher than a first temperature difference threshold, control the rotation speed of the outdoor fan to decrease; if the sixth temperature difference is lower than a second temperature difference threshold, control the rotation speed of the outdoor fan to increase, and the first temperature difference threshold is greater than the second temperature difference threshold.

[0023] The above technical solution has the following advantages or beneficial effects: By controlling the rotation speed of the outdoor fan according to the sixth temperature difference between the condensation temperature of the refrigerant and the coil temperature of the first heat exchanger, the rotation speed of the outdoor fan can be accurately controlled, effectively solving the problem of indoor ventilation and improving the indoor air quality.

[0024] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of the embodiments in conjunction with the accompanying drawings, where: Figure 1 It is a schematic structural diagram of an air conditioner according to an embodiment of the present invention; Figure 2 It is a schematic diagram of the refrigerant flow of an air conditioner according to an embodiment of the present invention; Figure 3 It is a schematic diagram of the refrigerant flow of an air conditioner according to another embodiment of the present invention; Figure 4 It is a flowchart of the compressor operating frequency control according to an embodiment of the present invention; Figure 5 It is a tabular schematic diagram of the change range of the compressor operating frequency according to an embodiment of the present invention; Figure 6 It is a flowchart of the first expansion valve control according to an embodiment of the present invention; Figure 7 It is a flowchart of the second expansion valve control according to an embodiment of the present invention; Figure 8 It is a tabular schematic diagram of the second opening increment according to an embodiment of the present invention; Figure 9 It is a tabular schematic diagram of the third opening increment according to an embodiment of the present invention; Figure 10 It is a tabular schematic diagram of the action trends of three expansion valves according to an embodiment of the present invention; Figure 11 It is a flowchart of the refrigerant flow of an air conditioner according to an embodiment of the present invention; Figure 12 It is a schematic diagram of the refrigerant flow of an air conditioner according to another embodiment of the present invention; Figure 13 It is a flowchart of the control method of an air conditioner according to another embodiment of the present invention; Figure 14 It is a flowchart of the controller control according to an embodiment of the present invention; Figure 15 It is a schematic diagram of the refrigerant flow of an air conditioner according to an embodiment of the present invention; Figure 16 It is a schematic diagram of the refrigerant flow of an air conditioner according to another embodiment of the present invention; Figure 17 It is a tabular schematic diagram of the solenoid valve control according to an embodiment of the present invention; Figure 18 It is a flowchart of the first defrosting mode according to an embodiment of the present invention; Figure 19 It is a flowchart of the second defrosting mode according to an embodiment of the present invention.

[0026] Reference numerals: Air conditioner 100; Water tank 1; first heat exchanger 2; second heat exchanger 3; third heat exchanger 4; compressor 5; first pipeline 6; second pipeline 7; third pipeline 8; first solenoid valve 10; second solenoid valve 11; third solenoid valve 12; first expansion valve 13; second expansion valve 14; third expansion valve 15; fourth solenoid valve 16; fifth solenoid valve 17; sixth solenoid valve 18; seventh solenoid valve 19; first water pump 20; second water pump 21. Specific implementation mode

[0027] The embodiments of the present invention will be described in detail below. The embodiments described with reference to the drawings are exemplary. The embodiments of the present invention will be described in detail below.

[0028] To solve the above problems, an embodiment of the first aspect of the present invention provides an air conditioner 100. By using this air conditioner 100, it is possible to achieve partial recovery of the waste heat of the air conditioner on the basis of achieving full heat recovery of the waste heat of the air conditioner, improve the comprehensive energy utilization rate of the air conditioning system, reduce the power consumption of the air conditioner 100, and achieve the purpose of saving electricity bills.

[0029] Reference will be made below Figure 1 to describe the air conditioner 100 according to the embodiments of the present invention, including: a water tank 1, a first heat exchanger 2, a second heat exchanger 3, a third heat exchanger 4, a compressor 5, a first pipeline 6, a second pipeline 7, a third pipeline 8, a first expansion valve 13, a second expansion valve 14, a third expansion valve 15, a first solenoid valve 10, a second solenoid valve 11, a third solenoid valve 12, a fourth solenoid valve 16, a fifth solenoid valve 17, a sixth solenoid valve 18, a seventh solenoid valve 19, and a controller.

[0030] Among them, the water tank 1 is used to store domestic water; the first heat exchanger 2 is located outdoors and is used to exchange heat for the circulating refrigerant; the second heat exchanger 3 is connected to the water tank 1 and is used to exchange heat for domestic water; the third heat exchanger 4 is located indoors and is used to adjust the indoor temperature; that is, the air conditioner is a combined heat and power unit.

[0031] The compressor 5 has an exhaust port and an intake port; wherein, the head end of the first pipeline 6 is connected to the exhaust port through the first solenoid valve 10, the head end of the second pipeline 7 is connected to the exhaust port through the second solenoid valve 11, the tail ends of the first pipeline 6 and the second pipeline 7 are both used to be connected to the head end of the third pipeline 8, the tail end of the third pipeline 8 is connected to the exhaust port through the third solenoid valve 12, the first heat exchanger 2 is located on the first pipeline 6, the second heat exchanger 3 is located on the second pipeline 7, and the third heat exchanger 4 is located on the third pipeline 8; the first expansion valve 13 is arranged on the first pipeline 6, the second expansion valve 14 is arranged on the second pipeline 7, and the third expansion valve 15 is arranged on the third pipeline 8; the first end of the fourth solenoid valve 16 is connected to the third solenoid valve 12 and the tail end of the third pipeline 8, the second end of the fourth solenoid valve 16 is connected to the first end of the fifth solenoid valve 17, the first end of the seventh solenoid valve 19, and the intake port, the first end of the sixth solenoid valve 18 is connected to the first solenoid valve 10, and the second end of the sixth solenoid valve 18 is connected to the head end of the first pipeline 6 and the second end of the seventh solenoid valve 19; a controller, which is configured to control the conduction conditions of each solenoid valve and each expansion valve according to the operating mode of the air conditioner 100. The first solenoid valve 10, the second solenoid valve 11, the third solenoid valve 12, the fourth solenoid valve 16, the fifth solenoid valve 17, the sixth solenoid valve 18, and the seventh solenoid valve 19 distribute the refrigerant flowing to the first heat exchanger 2, the second heat exchanger 3, and the third heat exchanger 4.

[0032] Specifically, to solve this problem, in this application, a method of parallel and series connection of three expansion valves and seven solenoid valves is adopted. When the air conditioner 100 operates in the full heat recovery mode or the partial heat recovery mode, the flow rate and direction of the refrigerant are changed by controlling the conduction of each expansion valve and each solenoid valve. Thus, both the full recovery of the waste heat of the air conditioner and the partial recovery of the waste heat of the air conditioner can be achieved. That is to say, according to the operating mode of the air conditioner 100, the conduction of each solenoid valve and each expansion valve is controlled. That is, according to the full heat recovery mode or the partial heat recovery mode, the conduction or closing of the first expansion valve 13, the second expansion valve 14, the third expansion valve 15, the first solenoid valve 10, the second solenoid valve 11, the third solenoid valve 12, the fourth solenoid valve 16, the fifth solenoid valve 17, the sixth solenoid valve 18 and the seventh solenoid valve 19 are controlled to change the flow rate and direction of the refrigerant, so that the second heat exchanger uses part or all of the refrigerant to heat the domestic water in the water tank 1, realizing the full recovery or partial recovery of the waste heat. Thus, compared with the existing air conditioner that adopts the scheme of two four-way valves in series and two one-way valves, or the scheme of one four-way valve and four one-way valves to achieve the full recovery of the waste heat, in this application, the scheme of parallel and series connection of three expansion valves and seven solenoid valves is adopted to more accurately distribute the flow rate of the refrigerant in the air conditioner 100, so that the air conditioner 100 can not only achieve the full recovery of the waste heat, but also achieve the partial recovery of the waste heat, improve the comprehensive energy utilization rate of the air conditioning system, reduce the power consumption of the air conditioner 100, and thus achieve the purpose of saving electricity bills.

[0033] Exemplarily, if it is determined that the operating mode of the air conditioner 100 is the full heat recovery mode, then by controlling the opening or closing of the first expansion valve 13, the second expansion valve 14, the third expansion valve 15, the first solenoid valve 10, the second solenoid valve 11, the third solenoid valve 12, the fourth solenoid valve 16, the fifth solenoid valve 17, the sixth solenoid valve 18, and the seventh solenoid valve 19, all the high-temperature gaseous refrigerant discharged from the compressor 5 flows into the second heat exchanger 3. The high-temperature gaseous refrigerant exchanges heat with the domestic water in the water tank 1 on the other side of the second heat exchanger 3. At this time, the second heat exchanger 3 uses all the refrigerant to generate heat for heating the domestic water in the water tank 1. Then, the refrigerant that has exchanged heat with the second heat exchanger 3 flows back to the compressor 5 after heat exchange through the third heat exchanger 4. Or, if it is determined that the operating mode of the air conditioner 100 is the partial heat recovery mode, then by controlling the opening or closing of the first expansion valve 13, the second expansion valve 14, the third expansion valve 15, the first solenoid valve 10, the second solenoid valve 11, the third solenoid valve 12, the fourth solenoid valve 16, the fifth solenoid valve 17, the sixth solenoid valve 18, and the seventh solenoid valve 19, part of the high-temperature gaseous refrigerant discharged from the compressor 5 flows into the second heat exchanger. Part of the high-temperature gaseous refrigerant exchanges heat with the domestic water in the water tank 1 on the other side of the second heat exchanger 3. At this time, the second heat exchanger 3 uses part of the refrigerant to generate heat for heating the domestic water in the water tank 1. At the same time, the other part of the high-temperature gaseous refrigerant discharged from the compressor 5 flows into the first heat exchanger 2 for heat exchange. Then, the refrigerant that has exchanged heat with the second heat exchanger 3 and the first exchanger flows back to the compressor 5 through the third heat exchanger 4. Thus, full heat recovery and partial heat recovery are achieved, improving the overall energy utilization rate of the air-conditioning system, reducing the power consumption of the air conditioner 100, and thus achieving the purpose of saving electricity costs.

[0034] For the air conditioner according to an embodiment of the present invention, three heat exchangers are respectively arranged on different pipelines, and seven solenoid valves are arranged between each pipeline and the exhaust port of the compressor to adjust the refrigerant flow direction. Thus, when the compressor discharges the refrigerant, it is no longer just that the refrigerant first passes through the water tank preferentially, but based on the operating mode of the air conditioner, the opening conditions of each solenoid valve and each expansion valve are controlled, so as to selectively control the refrigerant discharged from the exhaust port to enter the first pipeline, the second pipeline, and / or the third pipeline. Thus, while the air conditioner has multiple different operating modes, the problem of insufficient or excessive cooling or heating capacity caused by the refrigerant heating the water tank first is avoided.

[0035] In addition, based on the parallel and series connection of three expansion valves and seven solenoid valves, when the air conditioner 100 operates in the full heat recovery mode or partial heat recovery mode, the flow rate and direction of the refrigerant are changed by controlling the conduction of each expansion valve and each solenoid valve, so as to achieve full or partial recovery of waste heat. Therefore, compared with the existing air conditioner using the scheme of two four-way valves connected in series and two one-way valves, or the scheme of one four-way valve and four one-way valves to achieve full recovery of waste heat, the scheme of parallel and series connection of three expansion valves and seven solenoid valves is adopted in this application to more accurately distribute the flow rate of the refrigerant in the air conditioner 100, so that the air conditioner 100 can not only achieve full recovery of waste heat, but also achieve partial recovery of waste heat, improve the comprehensive energy utilization rate of the air conditioning system, reduce the power consumption of the air conditioner 100, and thus achieve the purpose of saving electricity bills.

[0036] In some embodiments, for controlling the conduction of each solenoid valve and each expansion valve according to the operating mode of the air conditioner 100, the controller is specifically configured to: when the operating mode is the simultaneous refrigeration and hot water production full heat recovery mode, control the second solenoid valve 11 and the fourth solenoid valve 16 to be both opened, and control the first solenoid valve 10, the third solenoid valve 12, the fifth solenoid valve 17, the sixth solenoid valve 18, and the seventh solenoid valve 19 to be all closed, and control the first expansion valve 13 to be closed, the second expansion valve 14 to be conductive, and the third expansion valve 15 to be conductive.

[0037] Specifically, if the air conditioner 100 operates in the simultaneous refrigeration and hot water production full heat recovery mode, control the second solenoid valve 11 and the fourth solenoid valve 16 to be both opened, and control the first solenoid valve 10, the third solenoid valve 12, the fifth solenoid valve 17, the sixth solenoid valve 18, and the seventh solenoid valve 19 to be all closed, and control the first expansion valve 13 to be closed, the second expansion valve 14 to be conductive, and the third expansion valve 15 to be conductive. At this time, the refrigerant flow direction is as Figure 2As shown, the second heat exchanger uses all the high-temperature gaseous refrigerant discharged by the compressor 5 to heat the water in the water tank 1. The refrigerant after heat exchange then exchanges heat with the indoor air through the third heat exchanger to lower the indoor temperature. Thus, the air conditioner 100 realizes the full heat recovery mode of simultaneous refrigeration and hot water production. That is to say, under the action of the second solenoid valve 11 being opened and the first solenoid valve 10 being closed, all the high-temperature gaseous refrigerant discharged by the compressor 5 flows into the second heat exchanger 3 through the second solenoid valve 11. The high-temperature gaseous refrigerant exchanges heat with the domestic water in the water tank 1 on the other side of the second heat exchanger 3. At this time, the second heat exchanger 3 uses all the refrigerant to generate heat for heating the domestic water in the water tank 1, that is, the air conditioner 100 operates in the full heat recovery mode of hot water production. The refrigerant after heat exchange flows into the third heat exchanger 4 after being throttled and depressurized to a low-temperature refrigerant by the second expansion valve 14 and the third expansion valve 15. The low-temperature refrigerant flowing in the third heat exchanger 4 exchanges heat with the indoor air to absorb the indoor heat to lower the indoor temperature. Thus, the air conditioner 100 operates in the refrigeration mode. Then, when the third solenoid valve 12, the fifth solenoid valve 17, and the seventh solenoid valve 19 are all closed, and under the opening action of the fourth solenoid valve 16, the refrigerant after heat exchange flows into the intake port of the compressor 5 through the fourth solenoid valve 16. Thus, the air conditioner 100 realizes the full recovery of waste heat during refrigeration.

[0038] In some embodiments, for controlling the conduction of each solenoid valve and each expansion valve according to the operating mode of the air conditioner 100, the controller is specifically configured to: when the operating mode is the partial heat recovery mode of simultaneous refrigeration and hot water production, control the first solenoid valve 10, the second solenoid valve 11, the fourth solenoid valve 16, and the sixth solenoid valve 18 to be all opened, and control the third solenoid valve 12, the fifth solenoid valve 17, and the seventh solenoid valve 19 to be all closed, and control the first expansion valve 13, the second expansion valve 14, and the third expansion valve 15 to be all conducted.

[0039] Specifically, when the air conditioner 100 operates in the partial heat recovery mode of simultaneous refrigeration and hot water production, the controller controls the first solenoid valve 10, the second solenoid valve 11, the fourth solenoid valve 16, and the sixth solenoid valve 18 to be all opened, and controls the third solenoid valve 12, the fifth solenoid valve 17, and the seventh solenoid valve 19 to be all closed, and controls the first expansion valve 13, the second expansion valve 14, and the third expansion valve 15 to be all conducted. At this time, the refrigerant flow direction is as Figure 3As shown, that is to say, under the action of the opening of both the first solenoid valve 10 and the second solenoid valve 11, a part of the high-temperature gaseous refrigerant discharged by the compressor 5 flows into the second heat exchanger 3 through the second solenoid valve 11. A part of the high-temperature gaseous refrigerant exchanges heat with the domestic water in the water tank 1 on the other side of the second heat exchanger 3. At this time, the second heat exchanger 3 uses part of the refrigerant to generate heat for heating the domestic water in the water tank 13, that is, the air conditioner 100 operates in the hot water partial heat recovery mode. The refrigerant after heat exchange with the second heat exchanger 3 is throttled and depressurized to a low-temperature refrigerant by the second expansion valve 14 in the second pipeline 7. At the same time, another part of the high-temperature gaseous refrigerant discharged by the compressor 5 flows into the first heat exchanger 2 through the first solenoid valve 10 and the sixth solenoid valve 18 under the action of the opening of the first solenoid valve 10 and the sixth solenoid valve 18. The first heat exchanger is located outdoors. The first heat exchanger 2 exchanges heat between part of the refrigerant and the outdoor air, that is, the refrigerant releases heat to the outdoor air to exchange heat for the circulating refrigerant. The refrigerant after heat exchange with the first heat exchanger 2 is throttled and depressurized to a low-temperature refrigerant by the first expansion valve 13 in the first pipeline 6 under the action of the conduction of the first expansion valve 13. The low-temperature refrigerant converging at the ends of the first pipeline 6 and the second pipeline 7 is throttled and depressurized by the third expansion valve 15. The further cooled low-temperature refrigerant enters the third heat exchanger 4. The low-temperature refrigerant flowing in the third heat exchanger 4 exchanges heat with the indoor air to absorb indoor heat to lower the indoor temperature. Thus, the air conditioner 100 operates in the cooling mode. Then, under the action of the closing of the third solenoid valve 12 and the seventh solenoid valve 19 and the opening of the fourth solenoid valve 16, the refrigerant after heat exchange flows into the intake port of the compressor 5 through the fourth solenoid valve 16. Thus, the air conditioner 100 realizes partial recovery of waste heat during cooling.

[0040] In some embodiments, the controller is further configured to: when the outdoor ambient temperature is within the normal operating range of the compressor 5, and the heat exchange temperature of the third heat exchanger is greater than the first preset temperature, and the shutdown duration of the compressor 5 reaches the preset duration, control the compressor 5 to start so that the air conditioner 100 operates in the cooling mode; when the outdoor ambient temperature is within the normal operating range of the compressor 5, and the domestic water temperature is lower than the second preset temperature, and the shutdown duration of the compressor 5 reaches the preset duration, control the compressor 5 to start so that the air conditioner 100 operates in the hot water mode, where the hot water mode includes the hot water total heat recovery mode and the hot water partial heat recovery mode; when the outdoor ambient temperature is within the normal operating range of the compressor 5, and the heat exchange temperature of the third heat exchanger is greater than the first preset temperature, and the domestic water temperature is lower than the second preset temperature, and the shutdown duration of the compressor 5 reaches the preset duration, control the compressor 5 to start so that the air conditioner 100 operates in the simultaneous cooling and hot water mode.

[0041] Among them, the first preset temperature can be understood as the temperature value preset for determining whether the indoor environment requires the air conditioner 100 to operate in the cooling mode for adjustment. The first preset temperature can be 5°C. The preset duration can be understood as the duration threshold for determining that the compressor 5 has not started. The preset duration can be 3 minutes. The second preset temperature can be understood as the temperature value preset for determining whether domestic water needs to be heated. The second preset temperature can be 55°C. When the third heat exchanger is a plate heat exchanger, the heat exchange temperature is the outlet water temperature of the plate heat exchanger.

[0042] Specifically, since the operation of the compressor 5 at extreme outdoor ambient temperatures may affect the lifespan of the compressor 5 and increase the risk of the compressor 5 malfunctioning. When the outdoor ambient temperature is within the normal operating range of the compressor 5, the compressor 5 can start and operate normally and maintain an efficient working state at this time. When the indoor ambient temperature is high, it will cause the heat exchange temperature between the indoor environment and the third heat exchanger to be high. Since the air conditioner 100 may start when the shutdown duration of the compressor 5 has not reached the preset duration, but the compressor 5 briefly shuts down due to special circumstances. Based on this, when the outdoor ambient temperature is within the normal operating range of the compressor 5, it indicates that the compressor 5 can start and operate normally and maintain an efficient working state at this time. And when the heat exchange temperature of the third heat exchanger is greater than the first preset temperature, it indicates that the indoor ambient temperature is high. At this time, the air conditioner 100 needs to operate in the cooling mode. And when the shutdown duration of the compressor 5 reaches the preset duration, it indicates that the compressor 5 has not started and the air conditioner 100 is in an inoperative state. Then control the compressor 5 to start so that the air conditioner 100 operates in the cooling mode. Thus, in this application, it is determined whether the air conditioner 100 operates in the cooling mode through the heat exchange temperature of the third heat exchanger, and at the same time, it is determined that the outdoor ambient temperature and the shutdown duration of the compressor 5 meet the requirements to ensure that the compressor 5 can start normally, effectively improving the service life and working efficiency of the compressor 5.

[0043] When the outdoor ambient temperature is within the normal operating range of the compressor 5, it indicates that the compressor 5 can start and operate normally and maintain an efficient working state at this time. And when the temperature of the domestic water is lower than the second preset temperature, it indicates that the temperature of the domestic water is low. At this time, the air conditioner 100 needs to operate in the hot water heating mode. And when the shutdown duration of the compressor 5 reaches the preset duration, it indicates that the compressor 5 has not started and the air conditioner 100 is in an inoperative state. Control the compressor 5 to start so that the air conditioner 100 operates in the hot water heating mode. Among them, the hot water heating mode includes the full heat recovery mode for hot water heating and the partial heat recovery mode for hot water heating. Thus, in this application, it is determined whether the air conditioner 100 operates in the hot water heating mode through the temperature of the domestic water, and at the same time, it is determined that the outdoor ambient temperature and the shutdown duration of the compressor 5 meet the requirements to ensure that the compressor 5 can start normally, effectively improving the service life and working efficiency of the compressor 5.

[0044] When the outdoor ambient temperature is within the normal operating range of the compressor 5, it indicates that the compressor 5 can start and operate normally and maintain an efficient working state. If the heat exchange temperature of the third heat exchanger is greater than the first preset temperature, it indicates that the indoor ambient temperature is relatively high, and at this time, the air conditioner needs to operate in the cooling mode. If the domestic water temperature is lower than the second preset temperature, it indicates that the domestic water temperature is relatively low, and at this time, the air conditioner 100 needs to operate in the hot water heating mode. When the shutdown duration of the compressor 5 reaches the preset duration, it indicates that the compressor 5 has not started and the air conditioner 100 is in an inoperative state. Then, control the compressor 5 to start so that the air conditioner 100 operates in both the cooling and hot water heating modes simultaneously. Thus, in this application, the air conditioner 100 is controlled to operate in both the cooling and hot water heating modes based on the heat exchange temperature of the third heat exchanger and the domestic water temperature, and at the same time, it is determined that the outdoor ambient temperature and the shutdown duration of the compressor 5 meet the requirements to ensure that the compressor 5 can start normally, effectively improving the service life and working efficiency of the compressor 5.

[0045] In addition, it should be noted that when the outdoor ambient temperature is not within the normal operating range of the compressor 5, the compressor 5 is not allowed to start. The normal operating range can be between -25°C and 48°C. If the heat exchange temperature of the third heat exchanger is lower than the first preset temperature, there is no need to operate in the cooling mode.

[0046] In some embodiments, after controlling the compressor 5 to start, as Figure 4 shown, the controller is further configured to execute step S1 to step S2: Step S1, determine the first temperature difference between the domestic water temperature and the target water temperature, and determine the second temperature difference between the heat exchange temperature of the third heat exchanger and the target heat exchange temperature.

[0047] Step S2, control the change range of the operating frequency of the compressor 5 according to the first temperature difference and the second temperature difference.

[0048] In an embodiment, the compressor 5 starts at an initial frequency f, and the initial frequency f is generally between 25 and 40 Hz. After the compressor 5 starts, it operates at the initial frequency f for 3 minutes, and after 3 minutes, the change range of the operating frequency of the compressor 5 is controlled according to the first temperature difference and the second temperature difference.

[0049] Wherein, the target water temperature is the domestic water temperature set by the user according to the demand Specifically, if the first temperature difference between the domestic water temperature and the target water temperature is less than 0, it indicates that the domestic water temperature has not reached the domestic water temperature set by the user according to the demand. In this case, the compressor 5 needs to be controlled to operate at a higher frequency to increase the refrigerant flow rate into the second heat exchanger 3, so that the refrigerant can exchange heat with the domestic water more efficiently, thereby quickly increasing the domestic water temperature. Moreover, the lower the first temperature difference, the higher the change range of the operating frequency of the compressor 5. And if the second temperature difference between the heat exchange temperature of the third heat exchanger and the target heat exchange temperature is smaller, it indicates that the refrigeration demand is greater, and the change range of the operating frequency of the compressor 5 is higher. Based on this, when controlling the operating frequency of the compressor 5, in order to balance the refrigeration and domestic hot water demands, the present application controls the change range of the operating frequency of the compressor 5 through the first temperature difference and the second temperature difference. That is to say, the refrigeration demand and the domestic hot water demand are determined through the first temperature difference and the second temperature difference, and then the corresponding change range of the operating frequency of the compressor 5 that meets the refrigeration demand and the domestic hot water demand is selected, and then the operating frequency of the compressor 5 is controlled according to this change range. Exemplarily, when both the first temperature difference and the second temperature difference are large, it indicates that the air conditioner 100 needs to quickly heat the domestic water and also needs to refrigerate efficiently. Then, the change range of the operating frequency of the compressor 5 is controlled to be high to simultaneously meet the refrigeration demand and the domestic hot water demand. When both the first temperature difference and the second temperature difference are small, the change range of the operating frequency of the compressor 5 is controlled to be low to simultaneously meet the refrigeration demand and the domestic hot water demand, and avoid energy waste caused by excessive adjustment. Thus, in the present application, the change range of the operating frequency of the compressor 5 is dynamically adjusted through the refrigeration demand and the domestic hot water demand, so as to balance the refrigeration and domestic hot water demands of the air conditioner, improve the overall efficiency of the system and the user experience.

[0050] In the embodiment, the corresponding relationship between the first temperature difference, the second temperature difference and the preset change range of the operating frequency of the compressor 5 can be preset in the controller. Thus, the corresponding preset change range can be obtained through the first temperature difference and the second temperature difference.

[0051] From Figure 5It can be seen that the variation range of the operating frequency of the compressor 5 with ΔT1≤ -8 is higher than that of the compressor 5 with -1<ΔT1<0, and the variation range of the operating frequency of the compressor 5 with ΔT2≥8 is higher than that of the compressor 5 with -1≤ΔT2< -0.5. When ΔT1≥0, it indicates that the temperature of domestic water has reached the temperature of domestic water set by the user according to the demand, and there is no need to increase the operating frequency of the compressor 5 to heat the domestic water. At this time, only the variation range of the operating frequency of the compressor 5 is controlled according to the second temperature difference; when ΔT2< -2, there is no refrigeration demand, and there is no need to increase the operating frequency of the compressor 5 to increase the refrigeration capacity. At this time, only the variation range of the operating frequency of the compressor 5 is controlled according to the first temperature difference. When the first temperature difference ΔT1 is the same, the larger the second temperature difference ΔT2, the larger the variation range of the operating frequency of the compressor 5. When the second temperature difference ΔT2 is the same, the larger the first temperature difference ΔT1, the larger the variation range of the operating frequency of the compressor 5.

[0052] Exemplarily, query through the first temperature difference ΔT1 and the second temperature difference ΔT2 Figure 5 to obtain the variation range of the operating frequency of the compressor 5. If the first temperature difference ΔT1≤ -8 and the second temperature difference ΔT2≥8, the variation range of the operating frequency of the compressor 5 is +8.

[0053] In some embodiments, when controlling the first expansion valve 13 in the hot water production partial heat recovery mode, as Figure 6 shown, the controller is further configured to execute steps S3 to S5: Step S3: Determine the third temperature difference between the coil temperature of the first heat exchanger and the outdoor ambient temperature.

[0054] Step S4: Determine the first opening increment of the first expansion valve 13 according to the third temperature difference.

[0055] Step S5: Adjust the opening of the first expansion valve 13 according to the first opening increment.

[0056] Specifically, the third temperature difference between the coil temperature of the first heat exchanger 2 and the outdoor ambient temperature is used to determine the superheat degree at the outlet of the first heat exchanger 2. When the third temperature difference is lower than the lower limit value of the temperature difference range corresponding to the superheat degree setting requirement, the superheat degree at the outlet of the first heat exchanger 2 is insufficient. That is to say, at this time, the refrigerant flow rate in the first heat exchanger 2 is too large, and the residence time of the refrigerant in the first heat exchanger 2 is relatively short. The refrigerant cannot fully exchange heat with the first heat exchanger 2. At this time, the opening degree of the first expansion valve 13 needs to be reduced to reduce the refrigerant flow rate, so that the refrigerant can fully exchange heat with the first heat exchanger 2 and increase the superheat degree at the outlet of the first heat exchanger 2 to make the superheat degree at the outlet of the first heat exchanger 2 meet the requirements. When the third temperature difference is higher than the upper limit value of the temperature difference range corresponding to the superheat degree setting requirement, the superheat degree at the outlet of the first heat exchanger 2 is too high. That is to say, at this time, the refrigerant flow rate in the first heat exchanger 2 is too small, and the residence time of the refrigerant in the first heat exchanger 2 is relatively long. The refrigerant fully exchanges heat with the first heat exchanger 2. At this time, the opening degree of the first expansion valve 13 needs to be increased to increase the refrigerant flow rate. Based on this, in order to ensure that the first heat exchanger 2 can operate efficiently and stably, in this application, when controlling the first expansion valve 13 in the hot water production part heat recovery mode, the first opening degree increment of the first expansion valve 13 is determined according to the third temperature difference, so as to change the superheat degree at the outlet of the first heat exchanger 2 through the first opening degree increment to make the superheat degree at the outlet of the first heat exchanger 2 meet the set requirements. That is to say, when the third temperature difference is lower than the lower limit value of the temperature difference range corresponding to the superheat degree setting requirement, the first opening degree increment is controlled to be negative, that is, the opening degree of the first expansion valve 13 is reduced, and the higher the third temperature difference, the greater the first opening degree increment, so as to increase the superheat degree at the outlet of the first heat exchanger 2 through the magnitude of the third temperature difference to make the superheat degree at the outlet of the first heat exchanger 2 meet the requirements. When the third temperature difference is higher than the upper limit value of the temperature difference range corresponding to the superheat degree setting requirement, the first opening degree increment is controlled to be positive, that is, the opening degree of the first expansion valve 13 is increased, and the superheat degree at the outlet of the first heat exchanger 2 is reduced to make the superheat degree at the outlet of the first heat exchanger 2 meet the requirements.

[0057] Exemplarily, when the domestic water temperature is greater than the second preset temperature, the opening degree of the first expansion valve 13 is controlled according to the third temperature difference between the coil temperature Tg of the first heat exchanger 2 and the outdoor ambient temperature Th, that is, the first opening degree increment of the first expansion valve 13 is determined according to the third temperature difference. The third temperature difference is expressed as Tg - Th. When 10°C ≤ Tg - Th < 15°C, the superheat degree of the first heat exchanger 2 meets the set requirements. If Tg - Th ≤ 5°C, the first opening degree increment ΔD is -5. If 5°C < Tg - Th < 10°C, the first opening degree increment ΔD1 is -2. If 10°C ≤ Tg - Th < 15°C, the first opening degree increment ΔD1 is 0. If Tg - Th ≥ 15°C, the first opening degree increment ΔD1 is +2. In addition, it should be noted that the opening degree of the first expansion valve 13 needs to be adjusted every 40 s.

[0058] In addition, it should be noted that when the temperature of domestic water is lower than the second preset temperature, the opening degree of the first expansion valve 13 is maintained at 0 steps.

[0059] In some embodiments, when controlling the second expansion valve 14 in the hot water production mode, as Figure 7 shown, the controller is further configured to execute step S6 to step S8: Step S6, obtaining the condensation temperature of the refrigerant and determining the fourth temperature difference between the condensation temperature and the domestic water temperature.

[0060] Step S7, determining the second opening degree increment of the second expansion valve 14 according to the domestic water temperature and the fourth temperature difference.

[0061] Step S8, adjusting the opening degree of the second expansion valve 14 according to the second opening degree increment.

[0062] Specifically, when the second heat exchanger 3 uses the refrigerant discharged by the compressor 5 to heat the domestic water in the water tank 1, if the opening degree of the second expansion valve 14 decreases and the increment of the opening degree of the second expansion valve 14 is smaller, at this time, the refrigerant discharge flow rate of the second heat exchanger 3 decreases, so that the refrigerant can fully exchange heat with the domestic water to enhance the temperature rise effect of the domestic water. If the opening degree of the second expansion valve 14 increases and the increment of the opening degree of the second expansion valve 14 is larger, at this time, the refrigerant discharge flow rate of the second heat exchanger 3 increases to slow down the temperature rise effect of the domestic water; and the superheat degree of the second heat exchanger 3 is judged through the fourth temperature difference between the condensation temperature and the domestic water temperature. When the fourth temperature difference is lower than the lower limit value of the temperature difference range corresponding to the superheat degree setting requirement, the superheat degree at the outlet of the second heat exchanger 3 is insufficient. That is to say, at this time, the refrigerant flow rate in the second heat exchanger 3 is too large and the residence time of the refrigerant in the second heat exchanger 3 is relatively short, and the refrigerant cannot fully exchange heat with the second heat exchanger 3. At this time, it is necessary to reduce the opening degree of the second expansion valve 14 to reduce the refrigerant flow rate, so that the refrigerant can fully exchange heat with the second heat exchanger 3 and increase the superheat degree at the outlet of the second heat exchanger 3 to make the superheat degree at the outlet of the second heat exchanger 3 meet the requirements. When the fourth temperature difference is higher than the upper limit value of the temperature difference range corresponding to the superheat degree setting requirement, the superheat degree at the outlet of the second heat exchanger 3 is too high. That is to say, at this time, the refrigerant flow rate in the second heat exchanger 3 is too small and the residence time of the refrigerant in the second heat exchanger 3 is relatively long, and the refrigerant fully exchanges heat with the second heat exchanger 3. At this time, it is necessary to increase the opening degree of the second expansion valve 14 to increase the refrigerant flow rate. Based on this, in order to achieve precise control of the superheat degree of the second heat exchanger 3 and achieve the purpose of heating domestic water, the second opening degree increment of the second expansion valve 14 is determined according to the domestic water temperature and the fourth temperature difference, so as to change the superheat degree at the outlet of the second heat exchanger 3 through the second opening degree increment, so that the superheat degree at the outlet of the second heat exchanger 3 meets the set requirements, and at the same time, the temperature rise effect of the domestic water is changed through the second opening degree increment, so that the domestic water temperature reaches the user-set temperature. That is to say, when the fourth temperature difference is lower than the lower limit value of the temperature difference range corresponding to the superheat degree setting requirement, the second opening degree increment is controlled to be negative, and the higher the fourth temperature difference, the larger the second opening degree increment, so as to increase the superheat degree at the outlet of the second heat exchanger 3 through the magnitude of the fourth temperature difference to make the superheat degree at the outlet of the second heat exchanger 3 meet the requirements. When the fourth temperature difference is higher than the upper limit value of the temperature difference range corresponding to the superheat degree setting requirement, the second opening degree increment is controlled to be positive to reduce the superheat degree at the outlet of the second heat exchanger 3 to make the superheat degree at the outlet of the second heat exchanger 3 meet the requirements. At the same time, if it is determined that the domestic water temperature is lower, the second opening degree increment is negative, and the smaller the second opening degree increment, the better the temperature rise effect of the domestic water. Therefore, in this application, the second opening degree increment of the second expansion valve 14 is determined according to the domestic water temperature and the fourth temperature difference, so as to achieve precise control of the superheat degree of the second heat exchanger 3 and achieve the purpose of heating domestic water.

[0063] In an embodiment, a correspondence relationship between the domestic water temperature and the fourth temperature difference and the second opening increment of the second expansion valve 14 can be preset in the controller. Thus, the corresponding second opening increment can be obtained based on the domestic water temperature and the fourth temperature difference.

[0064] It can be seen from Figure 8 that the second opening increment ΔD2 when Tn - Tx ≤ 0 is lower than the second opening increment ΔD2 when 0 < Tn - Tx < 5. When 10°C ≤ Tn - Tx < 15°C, the superheat of the second heat exchanger 3 meets the set requirements. When Tn - Tx is the same, the second opening increment ΔD2 when Tx < 45°C is lower than the second opening increment ΔD2 when 53 ≤ Tx, that is, when Tn - Tx is the same, the larger Tx is, the larger the second opening increment ΔD2 is.

[0065] Exemplarily, the fourth temperature difference can be expressed as the condensation temperature Tn - the domestic water temperature Tx. By querying the Figure 8 table in to obtain the second opening increment ΔD2. For example, if Tn - Tx ≤ 0 and 45 ≤ Tx < 50°C, the second opening increment ΔD2 is -4.

[0066] In some embodiments, when controlling the third expansion valve 15 in the simultaneous refrigeration and hot water production mode, the controller is further configured to: obtain the liquid pipe temperature of the third heat exchanger, the exhaust temperature of the compressor 5, and the inlet water temperature of the third heat exchanger; determine the fifth temperature difference between the inlet water temperature and the liquid pipe temperature; determine the third opening increment of the third expansion valve 15 based on the exhaust temperature and the fifth temperature difference; and adjust the opening of the third expansion valve 15 according to the third opening increment. Among them, the refrigerant temperature in the refrigerant side connection pipeline of the plate heat exchanger.

[0067] Specifically, the exhaust temperature of the compressor 5 indicates the high or low pressure of the low-pressure side of the refrigeration system. When the low-pressure is too high or too low, the refrigeration system becomes more unstable. At this time, the opening degree of the third expansion valve 15 needs to be changed to adjust the low-pressure by changing the refrigerant flow rate. In addition, the superheat degree of the third heat exchanger is judged by the fifth temperature difference between the inlet water temperature and the liquid pipe temperature. When the fifth temperature difference is lower than the lower limit value of the temperature difference range corresponding to the superheat degree setting requirement, the superheat degree at the outlet of the third heat exchanger is insufficient. That is to say, at this time, the refrigerant flow rate in the third heat exchanger is too large, and the residence time of the refrigerant in the third heat exchanger is relatively short, and the refrigerant cannot fully exchange heat with the third heat exchanger. At this time, the opening degree of the third expansion valve 15 needs to be reduced to reduce the refrigerant flow rate, so that the refrigerant can fully exchange heat with the third heat exchanger, and the superheat degree at the outlet of the third heat exchanger is increased to meet the requirements. Based on this, in order to accurately control the superheat degree of the third heat exchanger and balance the low-pressure of the refrigeration system at the same time, in this application, the third opening degree increment of the third expansion valve 15 is determined according to the exhaust temperature and the fifth temperature difference, so as to change the superheat degree at the outlet of the third heat exchanger through the third opening degree increment, so that the superheat degree at the outlet of the third heat exchanger meets the set requirements. That is to say, when the fifth temperature difference is lower than the set requirement, the second opening degree increment is controlled to be negative, and the higher the fifth temperature difference, the larger the third opening degree increment, so as to increase the superheat degree at the outlet of the third heat exchanger by the magnitude of the fifth temperature difference, so that the superheat degree at the outlet of the third heat exchanger meets the requirements. When the fifth temperature difference is lower than the lower limit value of the temperature difference range corresponding to the superheat degree setting requirement, the third opening degree increment is controlled to be negative, and the higher the fifth temperature difference, the larger the third opening degree increment, so as to increase the superheat degree at the outlet of the third heat exchanger by the magnitude of the fifth temperature difference, so that the superheat degree at the outlet of the third heat exchanger meets the requirements. At the same time, the low-pressure of the refrigeration system is changed through the third opening degree increment to balance the low-pressure of the refrigeration system.

[0068] In the embodiment, the corresponding relationship between the exhaust temperature, the fifth temperature difference and the third opening degree increment of the third expansion valve 15 can be preset in the controller. Thus, the corresponding third opening degree increment can be obtained through the exhaust temperature and the fifth temperature difference.

[0069] Exemplarily, as Figure 9 shown in the table, when Tj-Ty satisfies Tj-Ty≥2, the superheat degree of the third heat exchanger meets the set requirements. The third opening degree increment for 0<Tj-Ty<2 is greater than that for Tj-Ty≤0, that is, the higher the Tj-Ty, the higher the third opening degree increment. When Tj-Ty is the same, the third opening degree increment for Tp<90℃ is less than that for 90≤Tp<95℃, which is less than that for 95≤Tp, that is, when Tj-Ty is the same, the higher the Tp, the higher the third opening degree increment.

[0070] Exemplarily, the fifth temperature difference can be expressed as Tj - Ty, and the table in Figure 9 is queried through the exhaust gas temperature Tp and Tj - Ty to obtain the third opening increment ΔD3. For example, if Tj - Ty ≥ 2 and Tp < 90°C, then the third opening increment ΔD3 is 0. Figure 9 In the embodiments, when the first expansion valve 13, the second expansion valve 14, and the third expansion valve 15 affect each other and fluctuate, control is performed according to the rules in the table in Figure 10 .

[0071] In the embodiments, after the air conditioner unit is powered on, the first expansion valve, the second expansion valve, and the third expansion valve perform a reset operation. First, they open 480 steps, then close 540 steps, and then open to the initial number of steps. The three expansion valves act simultaneously, and the expansion valve can be an electronic expansion valve. Figure 10 The initial number of steps of the expansion valve is shown in the following table:

[0072]

[0073]

[0074] In some embodiments, the air conditioner 100 further includes an outdoor fan, and the controller is further configured to: in the full heat recovery mode of making hot water, control the outdoor fan to turn off; in the partial heat recovery mode of making hot water, determine the sixth temperature difference between the condensation temperature of the refrigerant and the coil temperature of the first heat exchanger 2, and control the rotational speed of the outdoor fan according to the sixth temperature difference.

[0075] Specifically, in order to accurately control the rotational speed of the outdoor fan, in this application, the rotational speed of the outdoor fan is controlled by the sixth temperature difference between the condensation temperature of the refrigerant and the coil temperature of the first heat exchanger 2, that is, the indoor ventilation and air change requirements are determined through the sixth temperature difference, and then the rotational speed of the outdoor fan is adjusted according to the indoor ventilation and air change requirements, so as to accurately control the rotational speed of the outdoor fan, effectively solve the indoor ventilation and air change problem, and improve the indoor air quality.

[0076] In some embodiments, for controlling the rotational speed of the outdoor fan according to the sixth temperature difference, the controller is specifically configured to: if the sixth temperature difference is higher than the first temperature difference threshold, control the rotational speed of the outdoor fan to decrease; if the sixth temperature difference is lower than the second temperature difference threshold, control the rotational speed of the outdoor fan to increase, and the first temperature difference threshold is greater than the second temperature difference threshold.

[0077] Specifically, if the sixth temperature difference is higher than the first temperature difference threshold, it indicates that less fresh air is needed indoors at this time, and the rotational speed of the outdoor fan is controlled to decrease; if the sixth temperature difference is lower than the second temperature difference threshold, it indicates that more fresh air is needed indoors at this time, and the rotational speed of the outdoor fan is controlled to increase. Thus, in this application, the rotational speed of the outdoor fan is controlled by the sixth temperature difference between the condensation temperature of the refrigerant and the coil temperature of the first heat exchanger 2, so as to accurately control the rotational speed of the outdoor fan, effectively solve the indoor ventilation and air change problem, and improve the indoor air quality.​​

[0078] Exemplarily, in the hot water production part heat recovery mode, control the sixth temperature difference Tn - Tg to satisfy 3°C ≤ Tn - Tg ≤ 5°C. If Tn - Tg > 5°C, then control the rotational speed of the outdoor fan to decrease; if Tn - Tg < 3°C, then control the rotational speed of the outdoor fan to increase.

[0079] In the embodiment, as Figure 2 shown, the air conditioner 100 includes a first water pump 20 and a second water pump 21. The first water pump 20 provides power for the water flow between the second heat exchanger and the water tank, heating to produce domestic hot water. The second water pump 21 delivers cold water and hot water to users, realizing the temperature reduction or increase in the user's room.

[0080] In the embodiment, in the hot water production mode, control the coil temperature Tg of the first heat exchanger 2 to satisfy 5 ≤ Tg ≤ 12°C. If Tg > 12°C, then control the rotational speed of the outdoor fan to decrease; if Tg < 5°C, then control the rotational speed of the outdoor fan to increase. Or, in the refrigeration mode, control the coil temperature of the first heat exchanger 2 to satisfy 35 ≤ Tg ≤ 45°C. If Tg < 35°C, then control the rotational speed of the outdoor fan to decrease; if Tg > 45°C, then control the rotational speed of the outdoor fan to increase.

[0081] In the embodiment, the control process of the first water pump is as follows: After the air conditioner 100 is powered on, the first water pump starts at the maximum rotational speed, detects the state of the water flow switch. If the water flow switch is detected to be off continuously for 15S, it means the water flow rate is too low, and the first water pump stops running. And when the domestic water temperature Tx - the second preset temperature ≥ 0°C, the first water pump is delayed to close for 1 minute. When controlling the rotational speed of the first water pump, the first water pump operates to maintain the outlet water temperature and the inlet water temperature of the second heat exchanger 3 to satisfy 4°C ≤ outlet water temperature - inlet water temperature ≤ 6°C. If the outlet water temperature - inlet water temperature < 4°C, the rotational speed of the first water pump decreases, and the duty cycle decreases by 10% per minute, adjusted once every 1 minute. If the outlet water temperature - inlet water temperature > 6°C, the rotational speed of the first water pump increases, and the duty cycle increases by 10% per minute, adjusted once every 1 minute.

[0082] In the embodiment, the control process of the second water pump is as follows: After the air conditioner 100 is powered on, the second water pump starts at the maximum rotational speed, detects the state of the water flow switch. If the water flow switch is detected to be off continuously for 15S, it means the water flow rate is too low, and the second water pump stops running. When the heat exchange temperature of the third heat exchanger - the first preset temperature > 5°C, the second water pump restarts.

[0083] When the heat exchange temperature of the third heat exchanger - the first preset temperature ≤ -2°C, the second water pump operates with an action of turning on for 2 minutes and turning off for 2 minutes. After the air conditioner 100 shuts down as a whole, the second water pump is turned off with a 2-minute delay. When controlling the rotational speed of the second water pump, the second water pump operates to maintain the outlet water temperature and the inlet water temperature of the second heat exchanger 3 such that 4°C ≤ inlet water temperature - outlet water temperature ≤ 6°C. If the inlet water temperature - outlet water temperature < 4°C, the rotational speed of the second water pump decreases, and the duty cycle decreases by 10% per minute, with adjustment once per minute. If the inlet water temperature - outlet water temperature > 6°C, the rotational speed of the second water pump increases, and the duty cycle increases by 10% per minute, with adjustment once per minute.

[0084] In addition, based on the above architecture, in some embodiments, when operating in the heating mode and it is determined that the outdoor ambient temperature is lower than the first preset temperature, during the heating startup stage of the heating mode, the second expansion valve 14 and the third expansion valve 15 are controlled to conduct, and the first expansion valve 13 is controlled to close; the third solenoid valve 12 and the fifth solenoid valve 17 are controlled to conduct, and the first solenoid valve 10, the second solenoid valve 11, the fourth solenoid valve 16, the sixth solenoid valve 18, and the seventh solenoid valve 19 are closed, so as to guide the refrigerant discharged from the exhaust port to sequentially enter the intake port after passing through the third pipeline 8 and the second pipeline 7. Thus, the refrigerant can exchange heat with the domestic water in the water tank 1, thereby using the water tank 1 as a heat source to ensure that the compressor 5 can be normally started under low-temperature conditions.

[0085] Specifically, if it is determined that the outdoor ambient temperature is lower than the first preset temperature and the air conditioner 100 is in the heating startup stage of the heating mode, then the controller controls the second expansion valve 14 and the third expansion valve 15 to conduct, and controls the first expansion valve 13 to close; controls the third solenoid valve 12 and the fifth solenoid valve 17 to conduct, and the first solenoid valve 10, the second solenoid valve 11, the fourth solenoid valve 16, the sixth solenoid valve 18, and the seventh solenoid valve 19 to close. At this time, the refrigerant flow direction is as Figure 11 shown. That is to say, the high-temperature refrigerant discharged from the exhaust port of the compressor 5 enters the third heat exchanger 4 after passing through the third solenoid valve 12, exchanges heat in the third heat exchanger 4 to heat the heating water, then passes through the third expansion valve 15 and the second expansion valve 14 and then enters the second heat exchanger 3 to exchange heat with the domestic water in the water tank 1, and then returns to the intake port of the compressor 5 through the fifth solenoid valve 17, thereby establishing a pressure difference for the refrigeration system and quickly increasing the oil temperature of the compressor 5, thus realizing the low-temperature startup of the compressor 5 and improving the reliability of the compressor 5.

[0086] In some embodiments, after the above valve actions are completed, the compressor operates at the initial frequency for a certain duration such as 3 minutes, and then performs normal loading and unloading operations after 3 minutes, thereby ensuring the stable operation of the compressor. At this time, the water tank provides heat as a low-temperature heat source. The value range of the initial frequency is 25 Hz to 45 Hz.

[0087] In some embodiments, the heating mode further includes a normal heating operation stage, and the controller is further configured to: when the compressor 5 meets the normal operation conditions, control the air conditioner 100 to enter the normal heating operation stage from the heating startup stage.

[0088] Specifically, after the compressor 5 starts, it is detected by controlling the compressor 5. If the compressor 5 meets the normal operation conditions, that is, all the operating parameters of the compressor 5 meet the normal operation requirements, it is confirmed that the compressor 5 has started successfully, and the air conditioner 100 can operate in the heating mode normally. Thus, the air conditioner 100 is controlled to enter the normal heating operation stage from the heating startup stage, and the controller controls the air conditioner 100 to perform heating.

[0089] In some embodiments, the normal operation condition is that the exhaust temperature of the compressor 5 is higher than the third preset temperature.

[0090] Specifically, the oil temperature of the compressor 5 should reach a sufficiently high working temperature for the compressor 5 to work normally. Therefore, a temperature sensor can be set at the exhaust port of the compressor 5 to monitor the exhaust temperature of the compressor 5, that is, to monitor the oil temperature of the compressor 5 through the exhaust temperature, and send the obtained exhaust temperature to the controller. If the exhaust temperature is higher than the third preset temperature, at this time the compressor 5 can work normally and air can be used as the heat source; conversely, if the exhaust temperature is not higher than the third preset temperature, the compressor 5 cannot work normally, and the air conditioner 100 should continue to maintain the heating startup stage and use the water tank 1 as the heat source to ensure that the compressor 5 can start normally.

[0091] In some embodiments, the controller is further configured to: in the heating startup stage, after the compressor 5 operates for a preset duration, determine that the exhaust temperature of the compressor 5 is lower than the third preset temperature; control the compressor 5 to increase the frequency to the maximum operating frequency.

[0092] Specifically, when the compressor 5 starts, to protect the compressor 5 from damage, it will operate at a certain initial frequency, such as 25 Hz, 35 Hz, 45 Hz, etc., which is not specifically limited here. After the compressor 5 operates at the initial frequency for a preset duration, it attempts to operate normally. At this time, the controller obtains the exhaust temperature of the compressor 5. If it is determined that the exhaust temperature is lower than the third preset temperature, at this time, the oil temperature of the compressor 5 is not high enough and it cannot start normally, then the controller controls the compressor 5 to increase the frequency to the maximum operating frequency, so as to quickly increase the oil temperature of the compressor 5 to ensure that the compressor 5 can meet the normal operation requirements, so that the air conditioner 100 can quickly heat for the user; conversely, if it is determined that the exhaust temperature is not lower than the third preset temperature, at this time, the compressor 5 can operate normally; then the air conditioner 5 enters the normal heating operation stage from the heating start stage, and uses the outdoor air as the heat source, and the controller controls the air conditioner 100 to heat. The third preset temperature can be set according to the actual situation, such as the third preset temperature is set to 50 °C, 55 °C, 60 °C, etc., which is not specifically limited here.

[0093] In some embodiments, the heating mode further includes a normal heating operation stage, and the controller is further configured to: receive an operation instruction for the heating mode, and determine that the outdoor ambient temperature is higher than the first preset temperature; control the air conditioner to directly enter the normal heating operation stage.

[0094] Specifically, if the controller receives an operation instruction for the heating mode and determines that the outdoor ambient temperature is higher than the first preset temperature, at this time, the outdoor air as the heat source can ensure the normal start of the compressor 5, and there is no need to use the water tank 1 as the heat source, then the air conditioner 100 can directly heat without other configurations by the controller, thereby shortening the response time and timely meeting the heating requirements of the user.

[0095] In some embodiments, the controller is further configured to, after entering the normal heating operation stage, control the first expansion valve 13 and the third expansion valve 15 to conduct, and control the second expansion valve 14 to close; control the first solenoid valve 10, the second solenoid valve 11, the fourth solenoid valve 12, the fifth solenoid valve 17 and the sixth solenoid valve 18 to be all closed, and control the third solenoid valve 12 and the seventh solenoid valve 19 to be all conducting.

[0096] Specifically, if the air conditioner 100 enters the normal heating operation stage, the controller controls the first expansion valve 13 and the third expansion valve 15 to conduct, and controls the second expansion valve 14 to close; controls the first solenoid valve 10, the second solenoid valve 11, the fourth solenoid valve 12, the fifth solenoid valve 17 and the sixth solenoid valve 18 to be all closed, and controls the third solenoid valve 12 and the seventh solenoid valve 19 to be all conducting. At this time, the refrigerant flow direction is as Figure 12As shown, that is to say, the high-temperature refrigerant discharged from the exhaust port of the compressor 5 enters the third heat exchanger 4 after passing through the third solenoid valve 12, and heat exchange occurs in the third heat exchanger 4 to heat the heating water. Then, it passes through the third expansion valve 15 and the first expansion valve 13, and then enters the first heat exchanger 2 to exchange heat with the outdoor air, and then returns to the intake port of the compressor 5 through the seventh solenoid valve 19 to complete the heating cycle of the air conditioner 100.

[0097] In some embodiments, the controller is further configured to: in the heating startup stage, obtain the domestic water temperature; when it is determined that the domestic water temperature is lower than the second preset temperature, control the water tank 1 to start electric heating; when it is determined that the domestic water temperature is higher than the second preset temperature, control the water tank 1 to stop electric heating.

[0098] Specifically, the domestic water temperature in the water tank 1 can be obtained through a sensor and sent to the controller. When the air conditioner 100 is in the heating startup stage, to ensure that the heat carried by the refrigerant after heat exchange with the domestic water in the water tank 1 can meet the low-temperature startup requirement of the compressor 5, the domestic water temperature should be high enough, that is, the domestic water temperature is lower than the second preset temperature. If the domestic water temperature is lower than the second preset temperature, the refrigerant cannot obtain enough heat after heat exchange with the domestic water in the water tank 1 at this time. Therefore, control the water tank 1 to start electric heating to heat the domestic water in the water tank 1; and when it is determined that the domestic water temperature is higher than the second preset temperature, stop the electric heating of the water tank 1 in time to avoid energy waste.

[0099] In some embodiments, as Figure 1 shown, the air conditioner 100 further includes a water pump 20.

[0100] Among them, the water pump 20 is arranged on the connecting pipeline between the second heat exchanger 3 and the water tank 1, and based on the design of the water pump 20, the controller is further configured to control the water pump 20 to operate at the maximum speed in the heating startup stage. And when there is no demand for heating water, after the air conditioner enters the normal heating operation stage, control the water pump 20 to close.

[0101] Specifically, in the heating startup stage, by controlling the water pump 20 to operate at the maximum speed, the heat exchange efficiency between the domestic water in the water tank 1 and the refrigerant is improved, so as to shorten the time consumed for the startup of the compressor 5 and quickly meet the heating demand of the user.

[0102] Exemplarily, referring to Figure 13 shown, the controller is further configured to perform the following steps.

[0103] Step S3, start.

[0104] Step S4, the operating mode of the air conditioner is the heating mode.

[0105] Step S5, detect the outdoor ambient temperature.

[0106] Step S6, determine whether the outdoor ambient temperature is lower than the first preset temperature. If so, execute Step S7; if not, execute Step S15.

[0107] Step S7, detect the temperature of domestic water.

[0108] Step S8, determine whether the temperature of domestic water is lower than the second preset temperature. If so, execute Step S10; if not, execute Step S9.

[0109] Step S9, turn on the electric heating of the water tank and execute Step S7.

[0110] Step S10, the third solenoid valve and the fifth solenoid valve are turned on, and the first solenoid valve, the second solenoid valve, the fourth solenoid valve, the sixth solenoid valve and the seventh solenoid valve are turned off.

[0111] Step S11, control the second expansion valve and the third expansion valve to be turned on, and control the first expansion valve to be turned off.

[0112] Step S12, the compressor runs for a preset time.

[0113] Step S13, determine whether the exhaust temperature of the compressor is lower than the third preset temperature. If so, execute Step S15; if not, execute Step S14.

[0114] Step S14, the compressor frequency is increased to the maximum operating frequency, and execute Step S12.

[0115] Step S15, the air conditioner enters the normal heating operation stage from the heating startup stage.

[0116] Step S16, turn off the electric heating of the water tank.

[0117] In the embodiment, the air conditioner 100 further includes a controller, and the controller is connected to the control valve. As Figure 14 shown, the controller is configured to execute the following steps.

[0118] Step S1, in the defrosting mode, determine that the temperature of domestic water is higher than the first preset temperature.

[0119] Among them, the first preset temperature can be understood as the temperature value of domestic water that can melt ice and frost preset according to experiments. The first preset temperature can be 10°C, and no specific limitation is made thereto.

[0120] Specifically, when the temperature of domestic water is low, the first heat exchanger 2 uses the heat of domestic water for defrosting. However, if the frost cannot be melted quickly and effectively, it will increase energy consumption and defrosting costs. Based on this, in the defrosting mode of this application, it is necessary to determine that the temperature of domestic water is higher than the first preset temperature before the heat of domestic water in the water tank 1 can be used for defrosting, so as to ensure the defrosting effect of the first heat exchanger 2 and improve energy utilization efficiency.

[0121] Step S2: Control the conduction of the control valve to guide the refrigerant discharged from the exhaust port to enter the intake port sequentially through the first pipeline 6 and the second pipeline 7.

[0122] Specifically, to solve this problem, this application adds the water tank 1 heat source as the defrosting heat source. When the air conditioner 100 is operating in the defrosting mode, the conduction of the control valve is controlled to guide the refrigerant discharged from the exhaust port to enter the intake port sequentially through the first pipeline 6 and the second pipeline 7. That is to say, the refrigerant discharged from the exhaust port of the compressor 5 no longer first enters the water tank 1 to heat the water tank 1, but first passes through the first heat exchanger 2 of the first pipeline 6 for defrosting, and then enters the second pipeline 7 to absorb the heat of the hot water in the water tank 1 through the second heat exchanger 3 and then returns to the compressor 5. Specifically, after the refrigerant absorbs the heat of the water tank 1 and returns to the compressor 5, the refrigerant is discharged from the exhaust port again. The refrigerant discharged from the exhaust port first passes through the first pipeline 6 and enters the first heat exchanger 2 under the action of the conduction of the control valve, so that the frost on the first heat exchanger 2 melts. Then, the heat-exchanged refrigerant enters the second heat exchanger 3 through the second pipeline 7 under the action of the conduction of the control valve and exchanges heat with the hot water in the water tank 1 in the second heat exchanger 3. The gaseous refrigerant after absorbing heat flows back to the intake port of the compressor 5, thus completing the refrigerant cycle of defrosting. Therefore, in this application, the flow direction of the refrigerant discharged from the exhaust port of the compressor 5 is changed through the control valve, so as to control the refrigerant to first pass through the first heat exchanger 2 and then flow to the water tank 1 when operating in the defrosting mode, so as to quickly defrost the first heat exchanger 2 by using the heat provided by the hot water in the water tank 1, and the heating of the user end will not be affected. At the same time, it is ensured that effective defrosting can be achieved even in extremely low temperatures, improving the reliability of the air conditioner 100.

[0123] According to the air conditioner 100 of an embodiment of the present invention, three heat exchangers are respectively arranged on different pipelines, and control valves are arranged between each pipeline and the exhaust port of the compressor 5 to adjust the refrigerant flow direction. Thus, when the air conditioner 100 operates in the defrosting mode, the refrigerant discharged by the compressor 5 does not preferentially pass through the water tank 1, but first enters the first heat exchanger 2 through the first pipeline 6 for defrosting. Thus, in this application, the flow direction of the refrigerant discharged from the exhaust port of the compressor 5 is changed by the control valve, so as to control the refrigerant to first pass through the first heat exchanger 2 and then flow to the water tank 1 when operating in the defrosting mode, so as to quickly defrost the first heat exchanger 2 by using the heat provided by the hot water in the water tank 1, and the heating of the user end is not affected. At the same time, it is ensured that effective defrosting can be achieved even at extremely low temperatures, improving the reliability of the air conditioner 100.

[0124] In the embodiment, first, the operation mode of the air conditioner 100 is judged. If the operation mode is not one or a combined mode of the heating or hot water heating mode, the first heat exchanger 2 will not frost, and the air conditioner 100 does not need to operate the defrosting mode. In one or a combined mode of the heating or hot water heating mode, then the operation ambient temperature of the air conditioner 100 is judged. If the operation ambient temperature ≥ the preset ambient temperature, where the preset ambient temperature can be 4°C, then the air conditioner 100 does not need to operate the defrosting mode; on the contrary, if the operation ambient temperature is less than the preset ambient temperature, at this time, the air conditioner 100 needs to judge whether to operate the defrosting mode.

[0125] In some embodiments, as Figure 1 shown, the air conditioner 100 further includes a first expansion valve 13, a second expansion valve 14 and a third expansion valve 15. Among them, the first expansion valve 13, the second expansion valve 14 and the third expansion valve 15 are used to adjust the pipeline flow rate, and the control valves include a first solenoid valve 10, a second solenoid valve 11, a third solenoid valve 12, a fourth solenoid valve 16, a fifth solenoid valve 17, a sixth solenoid valve 18 and a seventh solenoid valve 19.

[0126] Among them, the first expansion valve 13 is arranged on the first pipeline 6, the second expansion valve 14 is arranged on the second pipeline 7, and the third expansion valve 15 is arranged on the third pipeline 8; the first solenoid valve 10 is arranged between the exhaust port and the first end of the sixth solenoid valve 18, the second solenoid valve 11 is arranged between the exhaust port and the head end of the second pipeline 7, the second solenoid valve 11 is arranged between the exhaust port and the end of the third pipeline 8, the first end of the fourth solenoid valve 16 is connected to the third solenoid valve 12 and the end of the third pipeline 8, the second end of the fourth solenoid valve 16 is connected to the first end of the fifth solenoid valve 17, the first end of the seventh solenoid valve 19 and the intake port, and the second end of the sixth solenoid valve 18 is connected to the head end of the first pipeline 6 and the second end of the seventh solenoid valve 19.

[0127] Specifically, to solve this problem, when the air conditioner 100 operates in the defrosting mode, the conduction states of the first expansion valve 13, the second expansion valve 14, the third expansion valve 15, the first solenoid valve 10, the second solenoid valve 11, the third solenoid valve 12, the fourth solenoid valve 16, the fifth solenoid valve 17, the sixth solenoid valve 18 and the seventh solenoid valve 19 are controlled to guide the refrigerant discharged from the exhaust port to enter the intake port successively through the first pipeline 6 and the second pipeline 7. That is to say, the refrigerant absorbs the heat of the water tank 1, returns to the compressor 5, and then discharges the refrigerant through the exhaust port. The refrigerant discharged from the exhaust port first enters the first heat exchanger 2 through the first pipeline 6 under the action of the conduction states of the control valves, so that the frost on the first heat exchanger 2 melts. Then, the heat-exchanged refrigerant enters the second heat exchanger 3 through the second pipeline 7 and exchanges heat with the hot water in the water tank 1 in the second heat exchanger 3. The gaseous refrigerant after absorbing heat flows back to the intake port of the compressor 5, thus completing the refrigerant cycle for defrosting. Therefore, in this application, a scheme of three expansion valves and seven solenoid valves in parallel and series is adopted to change the flow direction of the refrigerant discharged from the exhaust port of the compressor 5, so as to control the refrigerant to pass through the first heat exchanger 2 first and then flow to the water tank 1 when operating in the defrosting mode, so as to quickly defrost the first heat exchanger 2 by using the heat provided by the hot water in the water tank 1, ensuring effective defrosting even in extremely low temperatures and improving the reliability of the air conditioner 100.

[0128] In some embodiments, for controlling the conduction states of the control valves to guide the refrigerant discharged from the exhaust port to enter the intake port successively through the first pipeline 6 and the second pipeline 7, the controller is specifically configured to perform the following steps.

[0129] Control the first expansion valve 13 and the second expansion valve 14 to be conductive.

[0130] Control the first solenoid valve 10, the fifth solenoid valve 17 and the sixth solenoid valve 18 to be conductive, and control the second solenoid valve 11, the fourth solenoid valve 16 and the seventh solenoid valve 19 to be closed, so as to guide the refrigerant discharged from the exhaust port to enter the intake port successively through the first pipeline 6 and the second pipeline 7.

[0131] Specifically, in the defrosting mode, the air conditioner 100 controls the first expansion valve 13 and the second expansion valve 14 to be turned on, controls the first solenoid valve 10, the fifth solenoid valve 17, and the sixth solenoid valve 18 to be turned on, and controls the second solenoid valve 11, the fourth solenoid valve 16, and the seventh solenoid valve 19 to be turned off. It guides the high-temperature gaseous refrigerant discharged from the exhaust port of the compressor 5 to enter the first heat exchanger 2 through the first pipeline 6, so that the frost on the first heat exchanger 2 melts. Then, the heat-exchanged refrigerant flows back to the intake port of the compressor 5 through the second pipeline 7. Thus, the refrigerant cycle for defrosting is completed. Therefore, in this application, a parallel and series connection method of seven solenoid valves and three electronic expansion valves is used to change the flow direction of the refrigerant discharged from the exhaust port of the compressor 5, so as to control the refrigerant to first pass through the first heat exchanger 2 and then flow to the water tank 1 when the defrosting mode is running, so as to quickly defrost the first heat exchanger 2 by using the heat provided by the hot water in the water tank 1. Moreover, the heating of the user end will not be affected, and at the same time, it can ensure effective defrosting even in extremely low temperatures, improving the reliability of the air conditioner 100.

[0132] In some embodiments, the defrosting mode includes a first defrosting mode and a second defrosting mode. Among them, in the first defrosting mode, the third expansion valve 15 and the third solenoid valve 12 are controlled to be turned off, and in the second defrosting mode, the third expansion valve 15 and the third solenoid valve 12 are controlled to be turned on.

[0133] Specifically, when the air conditioner 100 is running in the first defrosting mode, that is, the air conditioner 100 stops running the heating mode and then runs the defrosting mode, the air conditioner 100 realizes defrosting during shutdown. That is to say, as Figure 15 shown, under the action of the first solenoid valve 10 and the sixth solenoid valve 18 being turned on, and the second solenoid valve 11 and the third solenoid valve 12 being turned off, the high-temperature gaseous refrigerant discharged from the compressor 5 flows into the first heat exchanger 2 through the first pipeline 6. After that, the high-temperature gaseous refrigerant exchanges heat with the first heat exchanger 2 to melt the frost on the first heat exchanger 2. The heat-exchanged refrigerant enters the second pipeline 7 under the action of the first expansion valve 13 and the second expansion valve 14 being turned on and the third expansion valve 15 being turned off, and enters the second heat exchanger 3 after being throttled into a low-temperature and low-pressure vapor-liquid two-phase refrigerant by the first expansion valve 13 and the second expansion valve 14. In the second heat exchanger 3, it exchanges heat with the hot water in the water tank 1 to further reduce the temperature of the refrigerant. The heat-exchanged refrigerant enters the intake port of the compressor 5 through the fifth solenoid valve 17 under the action of the second solenoid valve 11, the fourth solenoid valve 16, and the seventh solenoid valve 19 being turned off and the fifth solenoid valve 17 being turned on, completing the refrigerant cycle for defrosting. Therefore, in this application, the on-off conditions of each solenoid valve and each expansion valve are controlled through the first defrosting mode, so as to control the refrigerant discharged from the exhaust port to enter the first pipeline 6 and the second pipeline 7 in sequence, so that the air conditioner 100 realizes defrosting during shutdown.

[0134] Alternatively, when the air conditioner 100 operates in the second defrosting mode, that is, when the air conditioner 100 operates in the heating mode and the defrosting mode simultaneously, the air conditioner 100 realizes defrosting without stopping, that is, as Figure 16 shown, a part of the high-temperature gaseous refrigerant discharged from the compressor 5 flows through the first pipeline 6 into the first heat exchanger 2 under the action of the conduction of the first electromagnetic valve 10 and the sixth electromagnetic valve 18 and the closing of the second electromagnetic valve 11. After that, the high-temperature gaseous refrigerant exchanges heat with the first heat exchanger 2 to melt the frost on the first heat exchanger 2. The refrigerant after heat exchange enters the second pipeline 7 under the action of the conduction of the first expansion valve 13 and the second expansion valve 14 and the closing of the third expansion valve 15, and enters the second heat exchanger 3 after being throttled into a low-temperature and low-pressure vapor-liquid two-phase refrigerant by the first expansion valve 13 and the second expansion valve 14. In the second heat exchanger 3, it exchanges heat with the hot water in the water tank 1 to further reduce the temperature of the refrigerant. The refrigerant after heat exchange enters the intake port of the compressor 5 through the fifth electromagnetic valve 17 under the action of the closing of the second electromagnetic valve 11, the fourth electromagnetic valve 16 and the seventh electromagnetic valve 19 and the conduction of the fifth electromagnetic valve 17. At the same time, another part of the high-temperature gaseous refrigerant enters the third heat exchanger 4 to exchange heat with the water on the other side of the third heat exchanger 4 under the action of the conduction of the third electromagnetic valve 12, so as to heat the heating circulating water. The refrigerant after heat exchange enters the second heat exchanger 3 after being throttled into a low-temperature and low-pressure vapor-liquid two-phase refrigerant by the third expansion valve 15 and the second expansion valve 14 under the action of the conduction of the third expansion valve 15. In the second heat exchanger 3, it exchanges heat with the hot water in the water tank 1 to further reduce the temperature of the refrigerant. The refrigerant after heat exchange enters the intake port of the compressor 5 through the fifth electromagnetic valve 17 under the action of the closing of the second electromagnetic valve 11, the fourth electromagnetic valve 16 and the seventh electromagnetic valve 19 and the conduction of the fifth electromagnetic valve 17, completing the refrigerant cycle of defrosting. Thus, in the present application, the conduction conditions of each electromagnetic valve and each expansion valve are controlled through the second defrosting mode, so as to control the refrigerant discharged from the exhaust port to enter the first pipeline 6 and the second pipeline 7 in sequence, and at the same time control the refrigerant discharged from the exhaust port to enter the third pipeline 8 and the second pipeline 7 in sequence, so that the air conditioner 100 can defrost while heating, realizing the function of defrosting without stopping.

[0135] In the embodiment, as Figure 17 shown, when the air conditioner 100 operates in the heating mode or the heating mode and the defrosting mode operate simultaneously, the conduction or closing conditions of the first electromagnetic valve 10, the second electromagnetic valve 11, the third electromagnetic valve 12, the fourth electromagnetic valve 16, the fifth electromagnetic valve 17, the sixth electromagnetic valve 18 and the seventh electromagnetic valve 19 are controlled.

[0136] In some embodiments, the controller is further configured to perform the following steps.

[0137] In the defrosting mode, control the compressor 5 to reduce the frequency to the first target operating frequency.

[0138] After the compressor 5 has been running for the first preset duration, control the first solenoid valve 10, the fifth solenoid valve 17, and the sixth solenoid valve 18 to conduct, control the first expansion valve 13 to be fully open, and control the opening degree of the second expansion valve 14 to be the target defrosting opening degree, and control the outdoor fan to stop.

[0139] After the compressor 5 runs for the first preset duration again, control the compressor 5 to increase its frequency to the target defrosting frequency.

[0140] Exemplarily, after the air conditioner 100 enters the defrosting mode, the compressor 5 reduces its frequency from the current operating frequency to the first target operating frequency, and the first target operating frequency can be 30 Hz. After the compressor 5 has been running for the first preset duration, where the first preset duration can be 15 seconds, control the first solenoid valve 10, the fifth solenoid valve 17, and the sixth solenoid valve 18 to conduct, close the second solenoid valve 11, the third solenoid valve 12, the fourth solenoid valve 16, the seventh solenoid valve 19, and the third expansion valve 15, open the first expansion valve 13 to the maximum, control the opening degree of the second expansion valve 14 to be the target defrosting opening degree, and control the outdoor fan to stop. The compressor 5 runs for the first preset duration again, and control the compressor 5 to increase its frequency to the target defrosting frequency, where the target defrosting frequency is between 40 and 60 Hz. Thus, adjusting the frequency of the compressor adaptively according to the above conditions can ensure the stable operation of the compressor during defrosting.

[0141] When it is detected that the coil temperature of the first heat exchanger 2 ≥ 15 °C, the compressor 5 reduces its frequency from the target defrosting frequency to 30 Hz. After the compressor 5 has been turned on for 15 seconds, the first solenoid valve 10, the second solenoid valve 11, the fourth solenoid valve 16, the fifth solenoid valve 17, and the sixth solenoid valve 18 are closed, the third solenoid valve 12 and the seventh solenoid valve 19 are opened, the third expansion valve 15 is opened to the maximum, the first expansion valve 13 is opened to the initial number of steps at this ambient temperature, the second expansion valve 14 is closed. After the compressor 5 runs for another 15 seconds, the compressor 5 increases to the target defrosting frequency, and after the target defrosting frequency is maintained for 3 minutes, normal frequency increase and decrease control is performed, and the speed of the outdoor fan is adjusted to the speed before defrosting and continues to run.

[0142] In addition, after the air conditioner 100 meets the defrosting conditions, the first expansion valve 13 is opened from the current number of steps to 500 steps, the third expansion valve 15 is closed to 0 steps, the second expansion valve 14 is opened from the current number of steps to the defrosting number of steps 350 steps. After defrosting ends, the first expansion valve 13 is opened to the initial number of steps, the third expansion valve 15 is opened to the maximum, and the second expansion valve 14 is closed from the current number of steps to 0 steps.

[0143] In some embodiments, in the first defrost mode, the controller is further configured to control the air conditioner 100 to exit the first defrost mode when the first defrost exit condition is met. The first defrost exit condition is that the coil temperature of the first heat exchanger 2 is higher than a preset temperature threshold or the defrost operation time reaches a second preset duration.

[0144] Wherein, the preset temperature threshold can be understood as the coil temperature value preset according to experiments for determining whether the frost layer on the first heat exchanger 2 has melted. The preset temperature threshold can be t2 + outdoor ambient temperature, where t2 ≤ -4 to -10. How to understand the second preset duration? It is the defrost mode operation time for determining whether the frost layer on the first heat exchanger 2 has melted. The second preset duration can be any value within the range of [30, 150].

[0145] Specifically, when the air conditioner 100 is operating in the first defrost mode, that is, the air conditioner 100 stops operating in the heating mode and then operates in the defrost mode. If it is detected that the first defrost exit condition is met, control the air conditioner 100 to exit the first defrost mode. That is, when it is detected that the coil temperature of the first heat exchanger 2 is higher than the preset temperature threshold, it indicates that the frost layer on the first heat exchanger 2 has melted at this time, and control the air conditioner 100 to exit the first defrost mode. Or, the defrost operation time reaches the second preset duration, that is, the operation time of the air conditioner 100 in the first defrost mode reaches the second preset duration. At this time, it indicates that the operation time of the first defrost mode is sufficient to remove the frost layer on the first heat exchanger 2, and then control the air conditioner 100 to exit the first defrost mode. Thus, in this application, it is determined whether the air conditioner 100 can exit the first defrost mode through the coil temperature and the defrost operation time, so as to ensure that while effectively melting the frost layer, unnecessary energy consumption is avoided.

[0146] In addition, if the coil temperature of the first heat exchanger 2 is lower than the preset temperature threshold, or the defrost operation time has not reached the second preset duration, then control the air conditioner 100 to continue to execute the first defrost mode.

[0147] In some embodiments, in the second defrost mode, the controller is further configured to control the operating frequency of the compressor 5 to be a second target operating frequency greater than the target defrost frequency after determining that the defrost operation time reaches a fourth preset duration and the coil temperature of the first heat exchanger 2 is lower than the preset temperature threshold. Wherein, the preset temperature threshold can be any value within the range of 10°C to 20°C.

[0148] Wherein, the fourth preset duration can be understood as the time preset according to experience when the heating capacity of the air conditioner 100 is insufficient to defrost. The fourth preset duration can be any value within the range of 5 min to 10 min. The fourth preset duration can be 5 min, 8 min or 10 min, and no specific limitation is made thereto.

[0149] Specifically, in the second defrosting mode, that is, when the air conditioner 100 is operating in the heating mode and the defrosting mode simultaneously, if it is determined that the defrosting operation time has reached the fourth preset duration and the coil temperature of the first heat exchanger 2 is lower than the preset temperature threshold, that is, after the second defrosting mode has been operating for a period of time and the frost layer on the first heat exchanger 2 has not completely melted, it indicates at this time that the heating capacity of the air conditioner 100 is insufficient. Then, the operating frequency of the compressor 5 is controlled to be the second target operating frequency. Among them, the second target operating frequency can be the highest frequency. At this time, it is necessary to increase the frequency of the compressor 5 to the highest frequency to meet the requirements of simultaneous defrosting and heating. That is to say, by increasing the operating frequency of the compressor 5, the refrigerant flow rate in the pipeline is increased, thereby increasing the heating capacity of the air conditioner 100, and further increasing the coil temperature of the first heat exchanger 2 so that the coil temperature reaches the preset temperature threshold, completing the defrosting process of the first heat exchanger 2. Thus, during the operation of the air conditioner 100 in the second defrosting mode, the heating capacity of the air conditioner 100 is determined through the defrosting operation time, and the operating frequency of the compressor 5 is adjusted by the heating capacity of the air conditioner 100 to increase the heating capacity of the air conditioner 100, thereby avoiding the problem that the first heat exchanger 2 cannot defrost quickly due to insufficient heating capacity of the air conditioner 100 and improving the defrosting speed.

[0150] In some embodiments, the controller is further configured to: when the second defrosting exit condition is met, control the air conditioner 100 to exit the second defrosting mode, where the second defrosting exit condition is that the coil temperature of the first heat exchanger 2 is higher than the preset temperature threshold.

[0151] Specifically, when the compressor increases from 30 Hz to the target defrosting frequency of 60 Hz, and the air conditioner 100 starts to operate in the heating mode and the defrosting mode simultaneously, that is, in the second defrosting mode, if it is detected that the second defrosting exit condition is met, control the air conditioner 100 to exit the second defrosting mode, that is, it is detected that the coil temperature of the first heat exchanger 2 is higher than the preset temperature threshold. At this time, it indicates that the frost layer on the first heat exchanger 2 has been melted, and control the air conditioner 100 to exit the second defrosting mode. The air conditioner 100 continues to operate in the heating mode. Thus, in this application, it is determined whether the air conditioner 100 can exit the second defrosting mode through the coil temperature, thereby ensuring that while effectively melting the frost layer, unnecessary energy consumption is avoided.

[0152] Exemplarily, in the second defrosting mode, after controlling the operating frequency of the compressor 5 to be the second target operating frequency, until the coil temperature of the first heat exchanger 2 is higher than the preset temperature threshold, the second defrosting mode is exited and the next heating operation is restarted.

[0153] In some embodiments, the controller is further configured to: when it is determined that the temperature difference between the coil temperature of the first heat exchanger 2 and the outdoor ambient temperature is within the frosting temperature range and the operating duration of the air conditioner 100 reaches a first preset duration, control the air conditioner 100 to enter the defrosting mode. The frosting temperature range can be -4 to -10.

[0154] Wherein, the first preset duration can be understood as the operating duration of the air conditioner 100 set according to experiments for determining whether the first heat exchanger 2 is frosted. The first preset duration can be any value within the range of min to 150 min. The first preset duration can be 20 min, 50 min, 90 min, 100 min, 140 min or 150 min, and no specific limitation is made thereto.

[0155] Specifically, since the first heat exchanger 2 is located outdoors, when the air conditioner 100 operates in the heating mode, the first heat exchanger 2 absorbs the outdoor ambient heat, resulting in a sharp drop in the outdoor ambient temperature. If the air conditioner 100 operates for a long time, it will cause the first heat exchanger 2 to frost. Based on this, in this application, it is determined whether the first heat exchanger 2 is frosted by whether the temperature difference between the coil temperature of the first heat exchanger 2 and the outdoor ambient temperature is within the frosting temperature range and by setting the first preset duration. That is to say, when it is determined that the temperature difference between the coil temperature of the first heat exchanger 2 and the outdoor ambient temperature is within the frosting temperature range, it indicates that the coil temperature of the first heat exchanger 2 and the outdoor ambient temperature are very low and it is easy to cause the first heat exchanger 2 to frost. And when it is determined that the operating duration of the air conditioner 100 reaches the first preset duration, it indicates that the long-term operation of the air conditioner 100 in the heating mode will cause the first heat exchanger 2 to frost. Then, control the air conditioner 100 to enter the defrosting mode to defrost the first heat exchanger 2. Thus, in this application, it is determined whether the first heat exchanger 2 is frosted by the temperature difference between the coil temperature of the first heat exchanger 2 and the outdoor ambient temperature and the operating duration of the air conditioner 100, so as to control the air conditioner 100 to operate in the defrosting mode after determining that the first heat exchanger 2 is frosted, so that the air conditioner 100 can defrost the first heat exchanger 2 in time.

[0156] Exemplarily, the frosting temperature range is -10°C to -4°C, and the first preset duration is 20 minutes. After the air conditioner 100 is turned on and operates in the heating mode, after the air conditioner 100 operates for a period of time, it is detected whether the air conditioner 100 meets the defrosting condition. That is, if the temperature difference between the coil temperature of the first heat exchanger 2 and the outdoor ambient temperature is between -10 and -4°C, and the operating duration of the air conditioner 100 reaches 20 minutes, that is, the operating duration of the air conditioner 100 in the heating mode reaches 20 minutes, then the air conditioner 100 is controlled to enter the defrosting mode. If not, it continues to operate in the heating mode. In some embodiments, the air conditioner 100 further includes a water pump (the first water pump 20), and the water pump is disposed on the connecting pipeline between the second heat exchanger 3 and the water tank 1. The controller is further configured to: in the defrosting mode, control the water pump to operate at the maximum speed. That is, when the air conditioner 100 is in the defrosting mode, control the water pump to operate at the maximum speed to provide the maximum power for the water flow between the second heat exchanger 3 and the water tank 1, thereby accelerating the absorption of the heat of the domestic hot water.

[0157] In addition, after the air conditioner 100 exits the defrosting mode, the water pump is controlled to turn off.

[0158] Next, refer to Figure 18 to describe the control process of the first defrosting mode of the embodiments of the present invention, and the specific content is as follows.

[0159] Step S8, start.

[0160] Step S9, determine whether the operating mode of the air conditioner is the heating mode. If so, execute Step S12; otherwise, execute Step S10.

[0161] Step S10, determine whether the operating mode of the air conditioner is the domestic hot water heating mode. If so, execute Step S12; otherwise, execute Step S11.

[0162] Step S11, if the air conditioner is not frosted, there is no need to execute the first defrosting mode.

[0163] Step S12, determine whether the operating ambient temperature of the air conditioner is less than 4°C. If so, execute Step S13 and Step S14; otherwise, execute Step S11.

[0164] Step S13, determine whether the coil temperature of the first heat exchanger is lower than the preset temperature threshold. If so, execute Step S15; otherwise, re-determine Step S13.

[0165] Step S14, determine whether the operating duration of the air conditioner reaches the first preset duration. If so, execute Step S15; otherwise, re-determine Step S14.

[0166] Step S15, the air conditioner needs to defrost.

[0167] Step S16: Determine whether the temperature of domestic water is higher than the first preset temperature. If yes, execute Step S18; otherwise, execute Step S17.

[0168] Step S17: The air conditioner is not allowed to defrost using the heat of the water tank.

[0169] Step S18: The air conditioner is allowed to defrost using the heat of the water tank.

[0170] Step S19: Determine whether the coil temperature of the first heat exchanger is higher than the preset temperature threshold. If yes, execute Step S21; otherwise, execute Step S20.

[0171] Step S20: Determine whether the defrost operation time reaches the second preset duration. If yes, execute Step S21; otherwise, execute Step S18.

[0172] Step S21: The air conditioner exits the first defrost mode.

[0173] Step S22: End.

[0174] The following refers to Figure 19 Describe the control process of the second defrost mode of the embodiment of the present invention, and the specific content is as follows.

[0175] Step S23: Start.

[0176] Step S24: The air conditioner operates in the heating mode.

[0177] Step S25: Input the coil temperature of the first heat exchanger.

[0178] Step S26: Input the operating duration of the air conditioner.

[0179] Step S27: Determine whether the coil temperature of the first heat exchanger and the operating duration of the air conditioner meet the defrost mode conditions, that is, determine whether the temperature difference between the coil temperature of the first heat exchanger and the outdoor ambient temperature is within the frosting temperature range, and determine whether the operating duration of the air conditioner reaches the first preset duration. If yes, execute Step S28; otherwise, execute Step S24.

[0180] Step S28: The compressor frequency is reduced to the first target operating frequency.

[0181] Step S29: Control the conduction condition of the solenoid valve.

[0182] Step S30: Control the conduction condition of the expansion valve.

[0183] Step S31: Control the outdoor fan to stop.

[0184] Step S32: Control the compressor to increase the frequency to the target defrost frequency.

[0185] Step S33: Determine whether the coil temperature of the first heat exchanger is higher than the preset temperature threshold. If yes, execute Step S36; otherwise, execute Step S34.

[0186] Step S34: Determine whether the defrost operation time has reached the fourth preset duration. If yes, execute Step S35; otherwise, execute Step S33.

[0187] Step S35: Control the compressor to increase its frequency to the second target operating frequency.

[0188] Step S36: Control the air conditioner to exit the second defrost mode.

[0189] Step S37: End.

[0190] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example.

[0191] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. An air conditioner, characterized in that: include: A water tank, wherein the water tank is used to store domestic water; A first heat exchanger, which is located outdoors and is used to exchange heat for the circulating refrigerant; A second heat exchanger, the second heat exchanger is connected to the water tank and is used to exchange heat for the domestic water; A third heat exchanger, the third heat exchanger is located indoors and is used to adjust the indoor temperature; a compressor having an exhaust port and an intake port; A first pipeline, a second pipeline and a third pipeline, wherein the head end of the first pipeline is connected to the exhaust port through a first solenoid valve, the head end of the second pipeline is connected to the exhaust port through a second solenoid valve, the end of the first pipeline and the end of the second pipeline are both used to connect to the head end of the third pipeline, the end of the third pipeline is connected to the exhaust port through a third solenoid valve, the first heat exchanger is located on the first pipeline, the second heat exchanger is located on the second pipeline, and the third heat exchanger is located on the third pipeline; a first expansion valve, a second expansion valve and a third expansion valve, wherein the first expansion valve is disposed on the first pipeline, the second expansion valve is disposed on the second pipeline, and the third expansion valve is disposed on the third pipeline; a fourth solenoid valve, a fifth solenoid valve, a sixth solenoid valve and a seventh solenoid valve, wherein the first end of the fourth solenoid valve is connected to the third solenoid valve and the end of the third pipeline, the second end of the fourth solenoid valve is connected to the first end of the fifth solenoid valve, the first end of the seventh solenoid valve and the air inlet, the first end of the sixth solenoid valve is connected to the first solenoid valve, and the second end of the sixth solenoid valve is connected to the head end of the first pipeline and the second end of the seventh solenoid valve; A controller is configured to control the conduction status of each solenoid valve and each expansion valve according to the operation mode of the air conditioner.

2. The air conditioner according to claim 1, characterized in that: For controlling the conduction of each solenoid valve and each expansion valve according to the operation mode of the air conditioner, the controller is specifically configured as follows: When the operating mode is a full heat recovery mode for simultaneous cooling and hot water production, the second solenoid valve and the fourth solenoid valve are both controlled to be open, and the first solenoid valve, the third solenoid valve, the fifth solenoid valve, the sixth solenoid valve and the seventh solenoid valve are all controlled to be closed, and the first expansion valve is controlled to be closed, the second expansion valve is controlled to be turned on, and the third expansion valve is controlled to be turned on.

3. The air conditioner according to claim 1, characterized in that: For controlling the conduction of each solenoid valve and each expansion valve according to the operation mode of the air conditioner, the controller is specifically configured as follows: When the operating mode is a simultaneous cooling and hot water partial heat recovery mode, the first solenoid valve, the second solenoid valve, the fourth solenoid valve and the sixth solenoid valve are all controlled to be opened, and the third solenoid valve, the fifth solenoid valve and the seventh solenoid valve are all controlled to be closed, and the first expansion valve, the second expansion valve and the third expansion valve are all controlled to be turned on.

4. The air conditioner according to any one of claims 1 to 3, characterized in that: The controller is also configured to: When the outdoor ambient temperature is within the normal operating range of the compressor, the heat exchange temperature of the third heat exchanger is greater than the first preset temperature, and the shutdown time of the compressor reaches a preset time, the compressor is controlled to start so that the air conditioner operates in a cooling mode; When the outdoor ambient temperature is within the normal operating range of the compressor, the domestic water temperature is lower than the second preset temperature, and the shutdown time of the compressor reaches a preset time, the compressor is controlled to start, so that the air conditioner operates in a hot water making mode, wherein the hot water making mode includes a hot water making full heat recovery mode and a hot water making partial heat recovery mode; When the outdoor ambient temperature is within the normal operating range of the compressor, the heat exchange temperature of the third heat exchanger is greater than the first preset temperature, the domestic water temperature is lower than the second preset temperature, and the shutdown time of the compressor reaches the preset time, the compressor is controlled to start so that the air conditioner runs in cooling and hot water making modes at the same time.

5. The air conditioner according to claim 4, characterized in that: After controlling the compressor to start, the controller is further configured to: Determine a first temperature difference between the domestic water temperature and the target water temperature, and determine a second temperature difference between the heat exchange temperature of the third heat exchanger and the target heat exchange temperature; The variation range of the compressor operating frequency is controlled according to the first temperature difference and the second temperature difference.

6. The air conditioner according to claim 3, characterized in that: When controlling the first expansion valve in the partial heat recovery mode for hot water production, the controller is further configured to: determining a third temperature difference between the coil temperature of the first heat exchanger and the outdoor ambient temperature; determining a first opening increment of the first expansion valve according to the third temperature difference; The opening degree of the first expansion valve is adjusted according to the first opening degree increment.

7. The air conditioner according to claim 4, characterized in that: When controlling the second expansion valve in the hot water making mode, the controller is further configured to: Obtaining a condensation temperature of the refrigerant, and determining a fourth temperature difference between the condensation temperature and a domestic water temperature; determining a second opening increment of the second expansion valve according to the domestic water temperature and the fourth temperature difference; The opening degree of the second expansion valve is adjusted according to the second opening degree increment.

8. The air conditioner according to claim 4, characterized in that: When controlling the third expansion valve in the simultaneous cooling and hot water making mode, the controller is further configured to: Acquire the liquid pipe temperature of the third heat exchanger, the exhaust temperature of the compressor, and the water inlet temperature of the third heat exchanger; determining a fifth temperature difference between the water inlet temperature and the liquid pipe temperature; determining a third opening increment of the third expansion valve according to the exhaust gas temperature and the fifth temperature difference; The opening degree of the third expansion valve is adjusted according to the third opening degree increment.

9. The air conditioner according to any one of claims 1 to 3, characterized in that: The air conditioner further includes an outdoor fan, and the controller is further configured as follows: In the full heat recovery mode for hot water production, controlling the outdoor fan to be turned off; In the partial heat recovery mode for hot water production, a sixth temperature difference between the condensation temperature of the refrigerant and the coil temperature of the first heat exchanger is determined, and the rotation speed of the outdoor fan is controlled according to the sixth temperature difference.

10. The air conditioner according to claim 9, characterized in that: For controlling the rotation speed of the outdoor fan according to the sixth temperature difference, the controller is specifically configured as follows: If the sixth temperature difference is higher than the first temperature difference threshold, controlling the speed of the outdoor fan to decrease; If the sixth temperature difference is lower than the second temperature difference threshold, the speed of the outdoor fan is controlled to increase, and the first temperature difference threshold is greater than the second temperature difference threshold.

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