Air conditioning system and control method thereof

Abstract

The invention relates to an air conditioning system and a control method thereof. The air conditioning system comprises a compressor, a four-way valve, an indoor heat exchanger, an outdoor heat exchanger, a water tank, a first branch and a second branch. The first end, the second end, the third end and the fourth end of the four-way valve are connected with an outlet of the compressor, an inlet of the compressor, the first end of the indoor heat exchanger and the first end of the outdoor heat exchanger in a one-to-one correspondence mode. The second end of the indoor heat exchanger is connected with the second end of the outdoor heat exchanger. The first end of the first branch and the first end of the second branch are both connected with an outlet of the compressor, the second end of the first branch and the second end of the second branch are both connected between the second end of the indoor heat exchanger and the second end of the outdoor heat exchanger, and the water tank is arranged on the second branch; the first end of the four-way valve, the first end of the first branch, the first end of the second branch and the second end of the outdoor heat exchanger can be arranged in an on-off mode, so that the problem that in the prior art, when an air conditioner operates in a heating mode in winter, the heating efficiency is poor is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioners, and in particular, to an air conditioning system and a control method thereof. Background Art

[0002] Air-conditioning heat recovery technology, as an important energy-saving measure in an air-conditioning system, has completely subverted the old routine of directly discharging waste heat to the external environment in the traditional air-conditioning refrigeration mode. This innovation not only avoids the ineffective loss of energy, reduces the degree of thermal pollution, but also effectively captures and converts this waste heat and re-uses it for beneficial purposes, such as preheating domestic water or indoor space, demonstrating the adherence to and practice of the principle of sustainable development.

[0003] In the severe winter, while providing warmth, the heat recovery air-conditioning system faces a challenge that cannot be ignored - frosting on the outdoor unit. As the operating time increases, the outdoor unit, which is the key indoor heat exchanger of the heat recovery system, will inevitably be covered with a layer of white frost due to the low temperature and high humidity environment. This seemingly soft frost film is actually a major enemy of heat exchange efficiency. It not only increases the resistance of air passing through the heat exchanger, resulting in an increase in thermal resistance, but also significantly weakens the heating capacity of the system, and sometimes even threatens the stable operation of the air conditioner. Therefore, an efficient defrosting strategy that does not affect indoor comfort has become an essential part of the design of the heat recovery air-conditioning system.

[0004] The existing air-conditioning systems usually adopt the means of reversing the four-way valve to guide the high-temperature refrigerant discharged by the compressor to defrost the outdoor unit. Although this method can remove the frost layer and restore the efficiency of the heat exchanger to a certain extent, it also brings new dilemmas. During the defrosting process, the low-temperature refrigerant generated after defrosting may flow back to the indoor side, causing an unexpected drop in the indoor temperature and resulting in poor heating efficiency of the air conditioner. This phenomenon not only affects the user experience, especially in winter when a stable indoor temperature is required, but also becomes a major difficulty faced by the heat recovery air-conditioning system. Summary of the Invention

[0005] The main object of the present invention is to provide an air conditioning system and a control method thereof to solve the problem of poor heating efficiency of existing air conditioners when operating in the heating mode in winter.

[0006] To achieve the above object, according to one aspect of the present invention, there is provided an air conditioning system, including a compressor, a four-way valve, an indoor heat exchanger, an outdoor heat exchanger, a water tank, a first branch and a second branch; the first end, the second end, the third end and the fourth end of the four-way valve are connected to the outlet of the compressor, the inlet of the compressor, the first end of the indoor heat exchanger and the first end of the outdoor heat exchanger in one-to-one correspondence, and the second end of the indoor heat exchanger and the second end of the outdoor heat exchanger are connected; the first end of the first branch and the first end of the second branch are both connected to the outlet of the compressor, and the second end of the first branch and the second end of the second branch are both connected between the second end of the indoor heat exchanger and the second end of the outdoor heat exchanger, and the water tank is arranged on the second branch; wherein, the first end of the four-way valve, the first branch, the first end of the second branch and the second end of the outdoor heat exchanger are all provided with on-off functions, so as to control the air conditioning system to selectively operate in at least one of multiple working modes including a main heating and auxiliary heating water mode and a single defrosting mode.

[0007] Further, the air conditioning system includes: a first expansion valve, the first expansion valve is arranged on the second branch and is located at one end of the water tank far away from the compressor; a second expansion valve, the second expansion valve is arranged at the second end of the indoor heat exchanger; a check valve, the check valve is arranged on the second branch and is located at one end of the first expansion valve far away from the water tank, and the inlet of the check valve is connected to the water tank.

[0008] Further, the air conditioning system includes: a first control valve, the first control valve is arranged at the first end of the four-way valve to control the on-off of the first end of the four-way valve; a second control valve, the second control valve is arranged on the first branch to control the on-off of the first branch; a third control valve, the third control valve is arranged on the second branch and is located between the water tank and the compressor to control the on-off of the second branch; a fourth control valve, the fourth control valve is arranged at the second end of the outdoor heat exchanger to control the on-off of the second end of the outdoor heat exchanger.

[0009] Further, when the air conditioning system is in the main heating and auxiliary heating water mode, the first control valve is opened, the second control valve is closed, the third control valve is opened, the fourth control valve is opened, the first end and the third end of the four-way valve are communicated, the second end and the fourth end of the four-way valve are communicated, and both the first expansion valve and the second expansion valve are used to adjust the refrigerant flow rate, so that most of the refrigerant flowing out of the outlet of the compressor flows to the indoor heat exchanger and a small part flows to the water tank.

[0010] Further, when the air conditioning system is in the single defrosting mode, the first control valve is closed, the second control valve is opened, the third control valve is closed, the fourth control valve is opened, the second end and the fourth end of the four-way valve are communicated, and the indoor heat exchanger and the second expansion valve do not work.

[0011] Further, the multiple working modes further include a main hot water heating and auxiliary heating mode. When the air-conditioning system is in the main hot water heating and auxiliary heating mode, the first control valve is opened, the second control valve is closed, the third control valve is opened, the fourth control valve is opened, the first end and the third end of the four-way valve are communicated, the second end and the fourth end of the four-way valve are communicated, and both the first expansion valve and the second expansion valve are used to adjust the refrigerant flow rate so that a small part of the refrigerant flowing out of the outlet of the compressor flows to the indoor heat exchanger and most of it flows to the water tank.

[0012] Further, the multiple working modes further include a single hot water heating mode. When the air-conditioning system is in the single hot water heating mode, the first control valve is closed, the second control valve is closed, the third control valve is opened, the fourth control valve is opened, the second end and the fourth end of the four-way valve are communicated, and the indoor heat exchanger and the second expansion valve do not work.

[0013] Further, the multiple working modes further include a single heating mode. When the air-conditioning system is in the single heating mode, the first control valve is opened, the second control valve is closed, the third control valve is closed, the fourth control valve is opened, the first end and the third end of the four-way valve are communicated, the second end and the fourth end of the four-way valve are communicated, and the second expansion valve is used to adjust the refrigerant flow rate.

[0014] According to another aspect of the present invention, a control method for an air-conditioning system is provided, which is applicable to the above-mentioned air-conditioning system. The control method of the air-conditioning system includes: when the air-conditioning system is turned on, obtaining the working mode selected by the user and the preset room temperature set by the user; when the user selects the main heating and auxiliary hot water heating mode, obtaining the preset water temperature set by the user, and controlling the air-conditioning system to operate in the main heating and auxiliary hot water heating mode; when the air-conditioning system operates in the heating mode for a first preset duration, obtaining the ambient temperature data outside and the temperature data of the heat exchange tubes of the outdoor heat exchanger of the air-conditioning system; determining whether the ambient temperature outside and the temperature data of the heat exchange tubes of the outdoor heat exchanger simultaneously meet the first defrosting condition and the second defrosting condition respectively; if the ambient temperature outside and the temperature data of the heat exchange tubes of the outdoor heat exchanger simultaneously meet the first defrosting condition and the second defrosting condition respectively, controlling the air-conditioning system to operate in the single defrosting mode; wherein, the first defrosting condition is that the ambient temperature outside is less than or equal to the preset outdoor ambient temperature within a second preset duration before the current moment, and the second defrosting condition is that the temperature data of the heat exchange tubes of the outdoor heat exchanger is less than or equal to the preset heat exchange tube temperature within a second preset duration before the current moment.

[0015] Further, the control method of the air-conditioning system further includes: when the air-conditioning system operates in the single defrosting mode for a third preset duration, controlling the air-conditioning system to switch to operate in the main heating and auxiliary hot water heating mode.

[0016] Further, the control method of the air-conditioning system further includes: if the ambient temperature outdoors and the temperature of the heat exchange tubes of the outdoor heat exchanger do not simultaneously meet the first defrosting condition and the second defrosting condition respectively, obtain the current indoor temperature; determine whether the current indoor temperature reaches the preset room temperature set by the user; if the current indoor temperature reaches the preset room temperature set by the user, control the air-conditioning system to operate in the main heating water and auxiliary heating mode.

[0017] Further, the control method of the air-conditioning system further includes: if the current indoor temperature does not reach the preset room temperature set by the user, return to the step starting with controlling the air-conditioning system to operate in the main heating and auxiliary heating water mode.

[0018] Further, the control method of the air-conditioning system further includes: after the air-conditioning system operates in the main heating water and auxiliary heating mode for a fourth preset duration, obtain the current temperature of the hot water in the water tank of the air-conditioning system; determine whether the current temperature of the hot water in the water tank reaches the preset water temperature set by the user; if the current temperature of the hot water in the water tank does not reach the preset water temperature set by the user, control the air-conditioning system to continue to operate in the main heating water and auxiliary heating mode.

[0019] Further, the control method of the air-conditioning system further includes: if the current temperature of the hot water in the water tank reaches the preset water temperature set by the user, control the air-conditioning system to operate in the single heating mode; after the air-conditioning system operates in the single heating mode for a first preset duration, obtain the ambient temperature data outdoors and the temperature data of the heat exchange tubes of the outdoor heat exchanger; determine whether the ambient temperature outdoors and the temperature of the heat exchange tubes of the outdoor heat exchanger simultaneously meet the first defrosting condition and the second defrosting condition respectively; if the ambient temperature outdoors and the temperature of the heat exchange tubes of the outdoor heat exchanger simultaneously meet the first defrosting condition and the second defrosting condition respectively, control the air-conditioning system to operate in the single defrosting mode; after the air-conditioning system operates in the single defrosting mode for a third preset duration, control the air-conditioning system to switch to operate in the single heating mode.

[0020] Further, when performing the step starting with obtaining the working mode selected by the user and the preset room temperature set by the user when the air-conditioning system is turned on, the control method of the air-conditioning system further includes: when the user selects the single heating mode, control the air-conditioning system to operate in the single heating mode; after the air-conditioning system operates in the single heating mode for a first preset duration, obtain the ambient temperature data outdoors and the temperature data of the heat exchange tubes of the outdoor heat exchanger; determine whether the ambient temperature outdoors and the temperature of the heat exchange tubes of the outdoor heat exchanger simultaneously meet the first defrosting condition and the second defrosting condition respectively; if the ambient temperature outdoors and the temperature of the heat exchange tubes of the outdoor heat exchanger simultaneously meet the first defrosting condition and the second defrosting condition respectively, control the air-conditioning system to operate in the single defrosting mode; after the air-conditioning system operates in the single defrosting mode for a third preset duration, control the air-conditioning system to switch to operate in the single heating mode.

[0021] Further, when performing the steps starting from obtaining the working mode selected by the user and the preset room temperature set by the user when the air-conditioning system is turned on, the control method of the air-conditioning system further includes: when the user selects the single hot water mode, controlling the air-conditioning system to operate in the single hot water mode; when the air-conditioning system operates in the single hot water mode for a first preset duration, obtaining the ambient temperature data outside and the temperature data of the heat exchange tubes of the outdoor heat exchanger; determining whether the ambient temperature outside and the temperature data of the heat exchange tubes of the outdoor heat exchanger simultaneously satisfy the first defrosting condition and the second defrosting condition respectively; if the ambient temperature outside and the temperature data of the heat exchange tubes of the outdoor heat exchanger simultaneously satisfy the first defrosting condition and the second defrosting condition respectively, controlling the air-conditioning system to operate in the single defrosting mode; when the air-conditioning system operates in the single defrosting mode for a third preset duration, controlling the air-conditioning system to switch to operating in the single hot water mode.

[0022] Applying the technical solution of the present invention, the air-conditioning system of the present invention includes a compressor, a four-way valve, an indoor heat exchanger, an outdoor heat exchanger, a water tank, a first branch and a second branch; the first end, the second end, the third end and the fourth end of the four-way valve are connected to the outlet of the compressor, the inlet of the compressor, the first end of the indoor heat exchanger and the first end of the outdoor heat exchanger in a one-to-one correspondence, and the second end of the indoor heat exchanger is connected to the second end of the outdoor heat exchanger; the first end of the first branch and the first end of the second branch are both connected to the outlet of the compressor, the second end of the first branch and the second end of the second branch are both connected between the second end of the indoor heat exchanger and the second end of the outdoor heat exchanger, and the water tank is arranged on the second branch; wherein the first end of the four-way valve, the first branch, the first end of the second branch and the second end of the outdoor heat exchanger can all be set to be on and off to control the air-conditioning system to selectively operate in one of a plurality of working modes including at least a main heating and auxiliary heating water mode and a single defrosting mode. Since the air-conditioning system needs to provide both indoor air heating and domestic hot water preparation in the heating and hot water modes in winter, the outdoor heat exchanger of the air-conditioning system is heavily loaded and easily frosted, thereby affecting the heating efficiency. The air-conditioning system of the present invention cleverly combines heat pump technology with condensation heat recovery technology, and achieves efficient and energy-saving heating and hot water supply by switching between multiple working modes, while effectively solving the defrosting problem during winter operation. In the main heating and auxiliary heating water modes, the air-conditioning system can intelligently distribute the refrigerant flow to ensure that the indoor comfort is not affected, and quickly preheat the water in the water tank. When the defrosting conditions are met, it can operate in a single defrost mode to reasonably distribute the flow direction of the refrigerant in the air-conditioning system and only use high-temperature refrigerant for defrosting. While efficiently defrosting the outdoor heat exchanger, it avoids the problem of low-temperature refrigerant entering the indoor side and affecting the user's winter heating comfort. This solves the problem of poor heating efficiency of air conditioners in the prior art when running in heating mode in winter. It not only improves energy utilization efficiency and reduces energy consumption, but also enhances the stability and reliability of the air-conditioning system, providing users with a more comfortable and convenient life experience, and has broad application prospects and market potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0024] Figure 1 A schematic diagram showing the refrigerant flow state of an embodiment of the air conditioning system of the present invention when in cooling and water heating modes;

[0025] Figure 2 Shows Figure 1 The schematic diagram of the refrigerant flow state of the air-conditioning system shown in FIG. 1 is in the defrosting mode;

[0026] Figure 3 shows Figure 1 Schematic diagram of the refrigerant flow state when the shown air conditioning system is in the single heating mode;

[0027] Figure 4 shows Figure 1 Schematic diagram of the refrigerant flow state when the shown air conditioning system is in the single hot water heating mode;

[0028] Figure 5 shows Figure 1 Control step diagram of an embodiment of the control method of the shown air conditioning system;

[0029] Figure 6 shows Figure 5 Schematic flow diagram of an embodiment of the control method of the shown air conditioning system.

[0030] Among them, the above-mentioned drawings include the following reference numerals:

[0031] 1. Compressor; 2. Four-way valve; 3. Indoor heat exchanger; 4. Outdoor heat exchanger; 5. First expansion valve; 6. Second expansion valve; 7. Water tank; 8. Check valve; 9. First control valve; 10. Second control valve; 11. Third control valve; 12. Fourth control valve; 101. First branch; 102. Second branch. Specific embodiments

[0032] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0033] As Figures 1 to 4 shown, the present invention provides an air conditioning system, including a compressor 1, a four-way valve 2, an indoor heat exchanger 3, an outdoor heat exchanger 4, a water tank 7, a first branch 101 and a second branch 102; the first end, the second end, the third end and the fourth end of the four-way valve 2 are respectively and correspondingly connected to the outlet of the compressor 1, the inlet of the compressor 1, the first end of the indoor heat exchanger 3 and the first end of the outdoor heat exchanger 4, and the second end of the indoor heat exchanger 3 is connected to the second end of the outdoor heat exchanger 4; the first end of the first branch 101 and the first end of the second branch 102 are both connected to the outlet of the compressor 1, and the second end of the first branch 101 and the second end of the second branch 102 are both connected between the second end of the indoor heat exchanger 3 and the second end of the outdoor heat exchanger 4, and the water tank 7 is arranged on the second branch 102; wherein, the first end of the four-way valve 2, the first branch 101, the first end of the second branch 102 and the second end of the outdoor heat exchanger 4 are all provided with on-off functions to control the air conditioning system to selectively operate in at least one of a variety of working modes including a main heating and auxiliary hot water mode and a single defrosting mode.

[0034] In the heating and hot water modes in winter, since the air conditioning system needs to provide indoor air heating and prepare domestic hot water, the load on the outdoor heat exchanger of the air conditioning system is relatively large, which easily causes frosting on the outdoor heat exchanger and thus affects the heating efficiency. The air conditioning system of the present invention cleverly combines heat pump technology with condensation heat recovery technology. Through the switching of multiple working modes, it realizes efficient and energy-saving heating and hot water supply, and effectively solves the defrosting problem during winter operation. In the main heating and auxiliary hot water heating mode, the air conditioning system can intelligently distribute the refrigerant flow rate to ensure that the indoor comfort is not affected, and at the same time quickly preheat the water in the water tank. When the defrosting condition is met, it can operate in a single defrost mode to reasonably distribute the flow direction of the refrigerant in the air conditioning system, and only use high-temperature refrigerant for defrosting, so as to efficiently defrost the outdoor heat exchanger while avoiding the problem that the user's winter heating comfort is affected due to the entry of low-temperature refrigerant into the indoor side. Thus, it solves the problem of poor heating efficiency of the existing air conditioner when operating in the heating mode in winter, not only improves the energy utilization efficiency, reduces energy consumption, but also enhances the stability and reliability of the air conditioning system, providing users with a more comfortable and convenient living experience, and having broad application prospects and market potential.

[0035] Specifically, the application scenarios of the air conditioning system of the present invention include places such as families, offices, and hotels that need to use air conditioning heating and hot water simultaneously or alternately, which can achieve efficient utilization of energy and environmental friendliness, and reduce energy waste and environmental pollution.

[0036] As Figures 1 to 4 shown, the air conditioning system includes: a first expansion valve 5, the first expansion valve 5 is arranged on the second branch 102 and is located at the end of the water tank 7 far from the compressor 1; a second expansion valve 6, the second expansion valve 6 is arranged at the second end of the indoor heat exchanger 3; a check valve 8, the check valve 8 is arranged on the second branch 102 and is located at the end of the first expansion valve 5 far from the water tank 7, and the inlet of the check valve 8 is connected to the water tank 7.

[0037] Among them, the first expansion valve 5 and the second expansion valve 6 can adjust the refrigerant flow rate. The air conditioning system can automatically adjust the opening degrees of the first expansion valve 5 and the second expansion valve 6 according to different working modes and external conditions to achieve precise control of the heating temperature and the hot water temperature. The function of the check valve 8 is to ensure the one-way flow of the refrigerant in the second branch 102 and avoid the reduction of the efficiency of the air conditioning system caused by refrigerant reflux. The coordinated action of the first expansion valve 5, the second expansion valve 6 and the check valve 8 can ensure the efficient and stable operation of the air conditioning system.

[0038] Specifically, both the first expansion valve 5 and the second expansion valve 6 are electronic expansion valves.

[0039] As Figures 1 to 4As shown in the figure, the air conditioning system includes: a first control valve 9, which is arranged at the first end of the four-way valve 2 to control the on-off of the first end of the four-way valve 2; a second control valve 10, which is arranged on the first branch 101 to control the on-off of the first branch 101; a third control valve 11, which is arranged on the second branch 102 and located between the water tank 7 and the compressor 1 to control the on-off of the second branch 102; and a fourth control valve 12, which is arranged at the second end of the outdoor heat exchanger 4 to control the on-off of the second end of the outdoor heat exchanger 4.

[0040] Through the control of the first control valve 9, the second control valve 10, the third control valve 11 and the fourth control valve 12, the air conditioning system of the present invention realizes the precise control of the refrigerant flow path in the air conditioning system, so as to be able to adapt to different working modes. The air conditioning system can intelligently adjust the opening and closing states of the first control valve 9, the second control valve 10, the third control valve 11 and the fourth control valve 12 according to the working mode selected by the user, so as to achieve the optimal distribution of the refrigerant, improve the overall efficiency of the air conditioning system and the user satisfaction.

[0041] Specifically, the first control valve 9, the second control valve 10, the third control valve 11 and the fourth control valve 12 are all solenoid valves.

[0042] As Figure 1 shown, when the air conditioning system is in the main heating and auxiliary hot water heating mode, the first control valve 9 is opened, the second control valve 10 is closed, the third control valve 11 is opened, the fourth control valve 12 is opened, the first end and the third end of the four-way valve 2 are communicated, the second end and the fourth end of the four-way valve 2 are communicated, and both the first expansion valve 5 and the second expansion valve 6 are used to adjust the refrigerant flow rate, so that most of the refrigerant flowing out of the outlet of the compressor 1 flows to the indoor heat exchanger 3 and a small part flows to the water tank 7. This main heating and auxiliary hot water heating mode realizes the reasonable distribution of the refrigerant between the indoor heat exchanger 3 and the water tank 7 through the control of the first control valve 9, the second control valve 10, the third control valve 11, the fourth control valve 12, the four-way valve 2, the first expansion valve 5 and the second expansion valve 6, so as to heat the water tank 7 into hot water on the premise of meeting the user's heating demand, improve the comprehensive utilization rate of energy, and is applicable to occasions such as families or offices in winter that require heating and hot water heating. By operating the main heating and auxiliary hot water heating mode, the comfortable adjustment of the indoor temperature and the rapid supply of hot water can be realized, and the user's quality of life is improved.

[0043] When the user has a heating demand, at the same time has a demand for using hot water, and the heating demand is strong, the air conditioning system will operate in the main heating and auxiliary hot water heating mode.

[0044] As Figure 2As shown, when the air-conditioning system is in the single defrost mode, the first control valve 9 is closed, the second control valve 10 is opened, the third control valve 11 is closed, the fourth control valve 12 is opened, the second end and the fourth end of the four-way valve 2 are connected, and the indoor heat exchanger 3 and the second expansion valve 6 do not work. This single defrost mode can directly introduce the high-temperature refrigerant flowing out of the outlet of the compressor 1 into the outdoor heat exchanger 4 through the first branch 101 by controlling the first control valve 9, the second control valve 10, the third control valve 11, the fourth control valve 12, the four-way valve 2, the first expansion valve 5 and the second expansion valve 6, so as to defrost the outdoor heat exchanger 4, avoiding the influence on the indoor comfort due to the entry of low-temperature refrigerant into the indoor heat exchanger 3, significantly improving the defrost efficiency of the air-conditioning system, ensuring the stability of the indoor temperature at the same time, improving the comfort of users in winter, and being applicable to the occasion where the heating efficiency is affected by the frosting of the outdoor heat exchanger of the outdoor unit on the outdoor side during the heating operation of the air-conditioning system in winter, realizing fast and efficient defrosting, avoiding the fluctuation of the indoor temperature at the same time, and improving the overall performance of the system.

[0045] When the outdoor ambient temperature and the temperature of the heat exchange tubes of the outdoor heat exchanger 4 respectively meet the first defrost condition and the second defrost condition at the same time, the air-conditioning system operates in the single defrost mode.

[0046] As Figure 1 shown, the multiple working modes also include the main hot water heating and auxiliary heating mode. When the air-conditioning system is in the main hot water heating and auxiliary heating mode, the first control valve 9 is opened, the second control valve 10 is closed, the third control valve 11 is opened, the fourth control valve 12 is opened, the first end and the third end of the four-way valve 2 are connected, the second end and the fourth end of the four-way valve 2 are connected, and both the first expansion valve 5 and the second expansion valve 6 are used to adjust the refrigerant flow rate, so that a small part of the refrigerant flowing out of the outlet of the compressor 1 flows to the indoor heat exchanger 3 and most of it flows to the water tank 7. This main hot water heating and auxiliary heating mode can adjust the distribution ratio of the refrigerant between the indoor heat exchanger 3 and the water tank 7 by controlling the first control valve 9, the second control valve 10, the third control valve 11, the fourth control valve 12, the four-way valve 2, the first expansion valve 5 and the second expansion valve 6, realizing the function of mainly heating water and supplementing heating, enabling the shell system to quickly prepare hot water while maintaining the comfort of the indoor environmental temperature, improving the comprehensive utilization rate of energy and user satisfaction.

[0047] When the user has a heating demand, a hot water usage demand at the same time, and the heating demand is weak, the air-conditioning system will operate in the main heating and auxiliary hot water heating mode.

[0048] As Figure 3As shown, the multiple working modes also include the single hot water heating mode. When the air conditioning system is in the single hot water heating mode, the first control valve 9 is closed, the second control valve 10 is closed, the third control valve 11 is opened, and the fourth control valve 12 is opened. The second end and the fourth end of the four-way valve 2 are connected. The indoor heat exchanger 3 and the second expansion valve 6 do not work. The control of the first control valve 9, the second control valve 10, the third control valve 11, the fourth control valve 12, the four-way valve 2, the first expansion valve 5, and the second expansion valve 6 in this single hot water heating mode can introduce all the refrigerant flowing out of the outlet of the compressor 1 into the water tank 7 for the preparation of hot water, improving the efficiency of hot water preparation, meeting the user's demand for hot water, and being applicable to occasions that require a large amount of hot water supply, such as families or offices, such as bathing and kitchen use. Through the operation of this mode, rapid supply of hot water can be achieved, enhancing the convenience of users' lives.

[0049] When the user only has the demand for heating water, the air conditioning system will operate in the main heating and auxiliary hot water heating mode, which is equivalent to an air source heat pump water heater at this time.

[0050] As Figure 4 shown, the multiple working modes also include the single heating mode. When the air conditioning system is in the single heating mode, the first control valve 9 is opened, the second control valve 10 is closed, the third control valve 11 is closed, and the fourth control valve 12 is opened. The first end and the third end of the four-way valve 2 are connected, and the second end and the fourth end of the four-way valve 2 are connected. The second expansion valve 6 is used to adjust the refrigerant flow rate. The control of the first control valve 9, the second control valve 10, the third control valve 11, the fourth control valve 12, the four-way valve 2, the first expansion valve 5, and the second expansion valve 6 in this single heating mode introduces all the refrigerant flowing out of the outlet of the compressor into the indoor heat exchanger 3 for heating, improving the heating efficiency of the air conditioning system, being able to quickly and efficiently increase the indoor environmental temperature, meeting the user's demand for a warm environment, and being applicable to occasions that require a rapid increase in indoor temperature, such as in winter in families or offices, such as when just arriving home or at the office. Through the operation of this mode, a rapid increase in indoor temperature can be achieved, enhancing the comfort of users' lives.

[0051] When the user only has the demand for heating, the air conditioning system will operate in the main heating and auxiliary hot water heating mode, which is equivalent to a heat pump air conditioner at this time.

[0052] As Figure 5 and Figure 6As shown in the figure, the present invention provides a control method for an air conditioning system, which is applicable to the above-mentioned air conditioning system. The control method of the air conditioning system includes: when the air conditioning system is turned on, obtaining the working mode selected by the user and the preset room temperature set by the user; when the user selects the main heating and auxiliary hot water heating mode, obtaining the preset water temperature set by the user, and controlling the air conditioning system to operate in the main heating and auxiliary hot water heating mode; after the air conditioning system operates in the heating mode for a first preset duration, obtaining the ambient temperature data outside and the temperature data of the heat exchange tubes of the outdoor heat exchanger 4 of the air conditioning system; judging whether the ambient temperature outside and the temperature of the heat exchange tubes of the outdoor heat exchanger 4 simultaneously meet the first defrosting condition and the second defrosting condition respectively; if the ambient temperature outside and the temperature of the heat exchange tubes of the outdoor heat exchanger 4 simultaneously meet the first defrosting condition and the second defrosting condition respectively, controlling the air conditioning system to operate in a single defrosting mode; wherein, the first defrosting condition is that the ambient temperature outside is less than or equal to the preset outdoor ambient temperature within a second preset duration before the current moment, and the second defrosting condition is that the temperature of the heat exchange tubes of the outdoor heat exchanger 4 is less than or equal to the preset heat exchange tube temperature within a second preset duration before the current moment.

[0053] When the air conditioning system of the present invention operates in heating mode in winter, if the external air humidity is relatively high, water vapor in the air is likely to condense on the surface of the outdoor heat exchanger 4, and the outdoor heat exchanger 4 will absorb external heat, resulting in the surface temperature being lower than the dew point temperature of the external air, ultimately causing frosting; when the user uses the main heating and auxiliary hot water heating mode, it will undoubtedly increase the load on the outdoor heat exchanger 4, making the surface of the outdoor heat exchanger 4 more prone to frosting, which increases the defrosting frequency of the air conditioning system. During defrosting, the indoor heat exchanger 3 of the air conditioning system will stop operating. If the low-temperature refrigerant flows through the indoor heat exchanger 3 at this time, it will affect the comfort of the indoor environment temperature. Therefore, the control method of the air conditioning system of the present invention is needed to improve the defrosting efficiency. During the defrosting process, the flow direction of the refrigerant is reasonably distributed to ensure that the high-temperature refrigerant will directly return to the compressor 1 in its entirety through the four-way valve 2 after defrosting the outdoor heat exchanger 4 and will not flow through the indoor heat exchanger 3, solving the problem of reducing indoor comfort due to the entry of low-temperature refrigerant during defrosting.

[0054] The control method of the air conditioning system of the present invention can, when operating in the main heating and auxiliary hot water heating mode, automatically judge whether to enter the single defrosting mode by monitoring the ambient temperature outside and the temperature of the heat exchange tubes of the outdoor heat exchanger 4 of the air conditioning system, enabling the air conditioning system to automatically adjust the operating mode according to external conditions, thereby realizing the efficient operation of the air conditioning system, avoiding unnecessary defrosting operations, improving energy utilization efficiency, while ensuring the stability of the indoor temperature and the rapid supply of hot water, and is applicable to occasions where heating and hot water supply are required in winter in families or offices, improving the quality of life of users.

[0055] Specifically, the first preset duration is a minutes, and the second preset duration is b minutes.

[0056] When the air-conditioning system is in the main heating and auxiliary hot water heating mode, a small portion of the refrigerant flows through the water tank 7 to heat the water in the water tank 7, and most of the refrigerant enters the indoor heat exchanger 3 to heat the air flowing into the room, so as to exert the maximum indoor heating capacity and meet the comfort requirements of users.

[0057] As Figure 6 shown, the control method of the air-conditioning system further includes: when the air-conditioning system operates in the single defrost mode for a third preset duration, controlling the air-conditioning system to switch to the main heating and auxiliary hot water heating mode.

[0058] Specifically, the third preset duration is c minutes.

[0059] As Figure 6 shown, the control method of the air-conditioning system further includes: if the outdoor environmental temperature and the temperature of the heat exchange tubes of the outdoor heat exchanger 4 do not simultaneously meet the first defrost condition and the second defrost condition respectively, obtaining the current indoor temperature; judging whether the current indoor temperature reaches the preset room temperature set by the user; if the current indoor temperature reaches the preset room temperature set by the user, controlling the air-conditioning system to operate in the main hot water heating and auxiliary heating mode. In this way, the control method of the air-conditioning system of the present invention can, when operating in the main heating and auxiliary hot water heating mode, automatically adjust the working mode of the air-conditioning system by monitoring the indoor temperature, mainly focusing on the rapid supply of hot water, realizing the dual functions of heating and heating water, improving the indoor comfort and energy utilization efficiency, realizing the rapid increase of the indoor temperature and the rapid supply of hot water, and improving the living quality of users.

[0060] When the air-conditioning system operates in the main hot water heating and auxiliary heating mode, most of the refrigerant flows through the water tank 7 to heat the water in the water tank 7, and only a small portion of the refrigerant enters the indoor heat exchanger 3 to maintain the indoor environmental temperature and meet the comfort requirements of users.

[0061] As Figure 6 shown, the control method of the air-conditioning system further includes: if the current indoor temperature does not reach the preset room temperature set by the user, returning to the step starting with controlling the air-conditioning system to operate in the main heating and auxiliary hot water heating mode.

[0062] As Figure 6As shown, the control method of the air-conditioning system further includes: after the air-conditioning system operates in the main hot water and auxiliary heating mode for a fourth preset duration, obtaining the current temperature of the hot water in the water tank 7 of the air-conditioning system; determining whether the current temperature of the hot water in the water tank 7 reaches the preset water temperature set by the user; if the current temperature of the hot water in the water tank 7 does not reach the preset water temperature set by the user, controlling the air-conditioning system to continue operating in the main hot water and auxiliary heating mode. In this way, the control method of the air-conditioning system of the present invention can, when operating in the main hot water and auxiliary heating mode, automatically adjust the operating mode of the air-conditioning system by monitoring the temperature of the hot water in the water tank 7. When the temperature of the hot water does not reach the preset water temperature set by the user, keep the operating mode of the air-conditioning system unchanged, mainly focusing on preparing hot water, and improving the energy utilization efficiency.

[0063] Specifically, the fourth preset duration is d minutes.

[0064] As Figure 6 As shown, the control method of the air-conditioning system further includes: if the current temperature of the hot water in the water tank 7 reaches the preset water temperature set by the user, controlling the air-conditioning system to operate in the single heating mode; after the air-conditioning system operates in the single heating mode for a first preset duration, obtaining the outdoor ambient temperature data and the temperature data of the heat exchange tubes of the outdoor heat exchanger 4; determining whether the outdoor ambient temperature and the temperature of the heat exchange tubes of the outdoor heat exchanger 4 simultaneously meet the first defrosting condition and the second defrosting condition respectively; if the outdoor ambient temperature and the temperature of the heat exchange tubes of the outdoor heat exchanger 4 simultaneously meet the first defrosting condition and the second defrosting condition respectively, controlling the air-conditioning system to operate in the single defrosting mode; after the air-conditioning system operates in the single defrosting mode for a third preset duration, controlling the air-conditioning system to switch to operate in the single heating mode. The control method of the air-conditioning system of the present invention can, when operating in the main hot water and auxiliary heating mode, automatically adjust the operating mode of the air-conditioning system by monitoring the temperature of the hot water in the water tank 7, the outdoor ambient temperature and the temperature of the heat exchange tubes of the outdoor heat exchanger 4. On the premise of ensuring that the temperature of the hot water reaches the preset water temperature set by the user, it can focus on heating the indoor air and automatically enter the single defrosting mode when needed to ensure the stability and high efficiency of the operation of the air-conditioning system, improving the user's quality of life and the energy utilization efficiency of the system.

[0065] When the air-conditioning system operates in the single heating mode, the refrigerant is disconnected from both the first branch 101 and the second branch 102 to freely adjust the indoor ambient temperature.

[0066] As Figure 6As shown, when performing the steps starting from obtaining the working mode selected by the user and the preset room temperature set by the user when the air-conditioning system is turned on, the control method of the air-conditioning system further includes: when the user selects the single heating mode, controlling the air-conditioning system to operate in the single heating mode; after the air-conditioning system operates in the single heating mode for the first preset duration, obtaining the ambient temperature data outside and the temperature data of the heat exchange tubes of the outdoor heat exchanger 4; determining whether the ambient temperature outside and the temperature of the heat exchange tubes of the outdoor heat exchanger 4 simultaneously meet the first defrosting condition and the second defrosting condition respectively; if the ambient temperature outside and the temperature of the heat exchange tubes of the outdoor heat exchanger 4 simultaneously meet the first defrosting condition and the second defrosting condition respectively, controlling the air-conditioning system to operate in the single defrosting mode; after the air-conditioning system operates in the single defrosting mode for the third preset duration, controlling the air-conditioning system to switch to operate in the single heating mode. The control method of the air-conditioning system of the present invention can, when operating in the single heating mode, automatically determine whether to enter the single defrosting mode by monitoring the ambient temperature outside and the temperature of the heat exchange tubes of the outdoor heat exchanger 4 of the air-conditioning system, thereby realizing the efficient operation of the air-conditioning system, avoiding unnecessary defrosting operations, improving the energy utilization efficiency, and at the same time ensuring the stability of the indoor temperature and the rapid supply of hot water. It is applicable to occasions where heating and hot water supply are required in winter families or offices, improving the quality of life of users.

[0067] As Figure 6 shown, the control method of the air-conditioning system further includes: if the ambient temperature outside and the temperature of the heat exchange tubes of the outdoor heat exchanger 4 do not simultaneously meet the first defrosting condition and the second defrosting condition respectively, returning to the step starting from controlling the air-conditioning system to operate in the single heating mode.

[0068] As Figure 6As shown, when performing the steps starting from obtaining the working mode selected by the user and the preset room temperature set by the user when the air-conditioning system is turned on, the control method of the air-conditioning system further includes: when the user selects the single hot water heating mode, controlling the air-conditioning system to operate in the single hot water heating mode; when the air-conditioning system operates in the single hot water heating mode for a first preset duration, obtaining the ambient temperature data outside and the temperature data of the heat exchange tubes of the outdoor heat exchanger 4; determining whether the ambient temperature outside and the temperature data of the heat exchange tubes of the outdoor heat exchanger 4 simultaneously meet the first defrosting condition and the second defrosting condition respectively; if the ambient temperature outside and the temperature data of the heat exchange tubes of the outdoor heat exchanger 4 simultaneously meet the first defrosting condition and the second defrosting condition respectively, controlling the air-conditioning system to operate in the single defrosting mode; when the air-conditioning system operates in the single defrosting mode for a third preset duration, controlling the air-conditioning system to switch to operate in the single hot water heating mode. The control method of the air-conditioning system of the present invention can, when operating in the single hot water heating mode, automatically determine whether to enter the single defrosting mode by monitoring the ambient temperature outside and the temperature data of the heat exchange tubes of the outdoor heat exchanger 4 of the air-conditioning system, thereby realizing the efficient operation of the air-conditioning system, avoiding unnecessary defrosting operations, improving the energy utilization efficiency, and at the same time ensuring the stability of the indoor temperature and the rapid supply of hot water, being applicable to occasions such as winter homes or offices where heating and hot water supply are required, and improving the user's quality of life.

[0069] As Figure 6 shown, the control method of the air-conditioning system further includes: if the ambient temperature outside and the temperature data of the heat exchange tubes of the outdoor heat exchanger 4 do not simultaneously meet the first defrosting condition and the second defrosting condition respectively, returning to the steps starting from controlling the air-conditioning system to operate in the single hot water heating mode.

[0070] When the air-conditioning system operates in the single hot water heating mode, the high-temperature refrigerant flowing out from the outlet of the compressor 1 directly enters the second branch 102 to heat the water in the water tank 7, and then the low-temperature refrigerant flowing out from the second branch 102 will directly pass through the outdoor heat exchanger 4 and the four-way valve 2 in sequence and then return to the compressor 1.

[0071] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0072] The air conditioning system of the present invention includes a compressor 1, a four-way valve 2, an indoor heat exchanger 3, an outdoor heat exchanger 4, a water tank 7, a first branch 101 and a second branch 102; the first end, the second end, the third end and the fourth end of the four-way valve 2 are respectively and correspondingly connected to the outlet of the compressor 1, the inlet of the compressor 1, the first end of the indoor heat exchanger 3 and the first end of the outdoor heat exchanger 4, and the second end of the indoor heat exchanger 3 is connected to the second end of the outdoor heat exchanger 4; the first end of the first branch 101 and the first end of the second branch 102 are both connected to the outlet of the compressor 1, and the second end of the first branch 101 and the second end of the second branch 102 are both connected between the second end of the indoor heat exchanger 3 and the second end of the outdoor heat exchanger 4, and the water tank 7 is arranged on the second branch 102; wherein, the first end of the four-way valve 2, the first branch 101, the first end of the second branch 102 and the second end of the outdoor heat exchanger 4 are all arranged to be open and closed, so as to control the air conditioning system to selectively operate in one of multiple working modes including at least a main heating and auxiliary heating water mode and a single defrosting mode. Since in the heating and hot water modes in winter, the air conditioning system needs to provide heating for indoor air and prepare domestic hot water, which results in a large load on the outdoor heat exchanger of the air conditioning system and is prone to frosting of the outdoor heat exchanger, thereby affecting the heating efficiency. The air conditioning system of the present invention ingeniously combines the heat pump technology with the condensation heat recovery technology, and through the switching of multiple working modes, realizes efficient and energy-saving heating and hot water supply, and effectively solves the defrosting problem during winter operation. In the main heating and auxiliary heating water mode, the air conditioning system can intelligently distribute the refrigerant flow rate to ensure that the indoor comfort is not affected, and at the same time quickly preheat the water in the water tank. When the defrosting condition is met, it can operate in a single defrosting mode to reasonably distribute the flow direction of the refrigerant in the air conditioning system, and only use high-temperature refrigerant for defrosting, so as to efficiently defrost the outdoor heat exchanger while avoiding the problem that the user's winter heating comfort is affected due to the entry of low-temperature refrigerant into the indoor side. Thus, the problem of poor heating efficiency of the existing air conditioner when operating in the heating mode in winter is solved. It not only improves the energy utilization efficiency, reduces the energy consumption, but also enhances the stability and reliability of the air conditioning system, providing a more comfortable and convenient living experience for users, and having broad application prospects and market potential.

[0073] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0074] Unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for the sake of convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationship. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the said technologies, methods, and devices should be regarded as part of the authorization specification. In all the examples shown and discussed here, any specific values should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0075] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by orientation terms such as "front, rear, upper, lower, left, right", "lateral, vertical, perpendicular, horizontal", and "top, bottom", etc. is usually based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description. Without contrary description, these orientation terms do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and thus cannot be construed as limiting the protection scope of the present invention; the orientation terms "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0076] For the convenience of description, spatial relative terms such as "above...", "over...", "on the upper surface of...", "above-mentioned", etc. can be used here to describe the spatial positional relationship between a device or feature shown in the drawings and other devices or features. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientation described in the drawings for the device. For example, if the device in the drawing is inverted, the device described as "above other devices or structures" or "over other devices or structures" will then be positioned "below other devices or structures" or "under other devices or structures". Thus, the exemplary term "above..." can include both the orientation of "above..." and "below...". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and corresponding interpretations should be made for the spatial relative descriptions used here.

[0077] In addition, it should be noted that the use of words such as "first", "second", etc. to limit components is only for the convenience of differentiating the corresponding components. Without otherwise stating, the above words have no special meaning, and thus cannot be construed as limiting the protection scope of the present invention.

[0078] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An air conditioning system, characterized in that: It comprises a compressor (1), a four-way valve (2), an indoor heat exchanger (3), an outdoor heat exchanger (4), a water tank (7), a first branch (101) and a second branch (102); The first end, the second end, the third end and the fourth end of the four-way valve (2) are connected to the outlet of the compressor (1), the inlet of the compressor (1), the first end of the indoor heat exchanger (3) and the first end of the outdoor heat exchanger (4) in a one-to-one correspondence, and the second end of the indoor heat exchanger (3) is connected to the second end of the outdoor heat exchanger (4); The first end of the first branch (101) and the first end of the second branch (102) are both connected to the outlet of the compressor (1), the second end of the first branch (101) and the second end of the second branch (102) are both connected between the second end of the indoor heat exchanger (3) and the second end of the outdoor heat exchanger (4), and the water tank (7) is arranged on the second branch (102); The first end of the four-way valve (2), the first branch (101), the first end of the second branch (102) and the second end of the outdoor heat exchanger (4) can be set to be on and off to control the air-conditioning system to selectively operate in one of a plurality of working modes including at least a main heating and auxiliary water heating mode and a single defrosting mode.

2. The air conditioning system according to claim 1, characterized in that: The air conditioning system comprises: a first expansion valve (5), the first expansion valve (5) being arranged on the second branch (102) and located at an end of the water tank (7) away from the compressor (1); a second expansion valve (6), the second expansion valve (6) being arranged at a second end of the indoor heat exchanger (3); A one-way valve (8), the one-way valve (8) being arranged on the second branch (102) and located at an end of the first expansion valve (5) away from the water tank (7), and an inlet of the one-way valve (8) being connected to the water tank (7).

3. The air conditioning system according to claim 2, characterized in that: The air conditioning system comprises: a first control valve (9), the first control valve (9) being arranged at a first end of the four-way valve (2) to control the on-off of the first end of the four-way valve (2); a second control valve (10), the second control valve (10) being arranged on the first branch (101) to control the on-off of the first branch (101); a third control valve (11), the third control valve (11) being arranged on the second branch (102) and located between the water tank (7) and the compressor (1) to control the on-off of the second branch (102); A fourth control valve (12), the fourth control valve (12) being arranged at the second end of the outdoor heat exchanger (4) to control the on-off of the second end of the outdoor heat exchanger (4).

4. The air conditioning system according to claim 3, characterized in that: When the air-conditioning system is in the main heating and auxiliary water heating mode, the first control valve (9) is opened, the second control valve (10) is closed, the third control valve (11) is opened, the fourth control valve (12) is opened, the first end and the third end of the four-way valve (2) are connected, the second end and the fourth end of the four-way valve (2) are connected, and the first expansion valve (5) and the second expansion valve (6) are both used to adjust the refrigerant flow rate so that most of the refrigerant flowing out of the outlet of the compressor (1) flows to the indoor heat exchanger (3) and a small part flows to the water tank (7).

5. The air conditioning system according to claim 3, characterized in that: When the air-conditioning system is in the single defrost mode, the first control valve (9) is closed, the second control valve (10) is opened, the third control valve (11) is closed, the fourth control valve (12) is opened, the second end and the fourth end of the four-way valve (2) are connected, and the indoor heat exchanger (3) and the second expansion valve (6) are not working.

6. The air conditioning system according to claim 3, characterized in that: The multiple working modes also include a main water heating and auxiliary heating mode. When the air-conditioning system is in the main water heating and auxiliary heating mode, the first control valve (9) is opened, the second control valve (10) is closed, the third control valve (11) is opened, the fourth control valve (12) is opened, the first end and the third end of the four-way valve (2) are connected, the second end and the fourth end of the four-way valve (2) are connected, and the first expansion valve (5) and the second expansion valve (6) are both used to adjust the refrigerant flow rate so that a small part of the refrigerant flowing out of the outlet of the compressor (1) flows to the indoor heat exchanger (3) and most of it flows to the water tank (7).

7. The air conditioning system according to claim 3, characterized in that: The multiple working modes also include a water heating mode only. When the air-conditioning system is in the water heating mode only, the first control valve (9) is closed, the second control valve (10) is closed, the third control valve (11) is opened, the fourth control valve (12) is opened, the second end and the fourth end of the four-way valve (2) are connected, and the indoor heat exchanger (3) and the second expansion valve (6) are not working.

8. The air conditioning system according to claim 3, characterized in that: The multiple working modes also include a heating-only mode. When the air-conditioning system is in the heating-only mode, the first control valve (9) is opened, the second control valve (10) is closed, the third control valve (11) is closed, the fourth control valve (12) is opened, the first end and the third end of the four-way valve (2) are connected, the second end and the fourth end of the four-way valve (2) are connected, and the second expansion valve (6) is used to adjust the refrigerant flow.

9. A method for controlling an air conditioning system, characterized in that: Applicable to the air conditioning system according to any one of claims 1 to 8, the control method of the air conditioning system comprises: When the air conditioning system is turned on, obtaining the operating mode selected by the user and the preset room temperature set by the user; When the user selects the main heating and auxiliary water heating modes, the preset water temperature set by the user is obtained, and the air conditioning system is controlled to operate in the main heating and auxiliary water heating modes; After the air conditioning system is operated in a heating mode for a first preset time, outdoor ambient temperature data and temperature data of a heat exchange tube of an outdoor heat exchanger (4) of the air conditioning system are obtained; Determining whether the outdoor ambient temperature and the temperature of the heat exchange tube of the outdoor heat exchanger (4) respectively satisfy a first defrosting condition and a second defrosting condition at the same time; If the outdoor ambient temperature and the temperature of the heat exchange tube of the outdoor heat exchanger (4) respectively meet the first defrosting condition and the second defrosting condition at the same time, the air conditioning system is controlled to operate in a single defrosting mode; The first defrost condition is that the outdoor ambient temperature is less than or equal to the preset outdoor ambient temperature within a second preset time period before the current moment, and the second defrost condition is that the temperature of the heat exchange tube of the outdoor heat exchanger (4) is less than or equal to the preset heat exchange tube temperature within the second preset time period before the current moment.

10. The control method of the air conditioning system according to claim 9, characterized in that: The control method of the air conditioning system further includes: After the air-conditioning system operates in the single defrost mode for a third preset time, the air-conditioning system is controlled to switch to operate in the main heating and auxiliary water heating mode.

11. The control method of the air conditioning system according to claim 9, characterized in that: The control method of the air conditioning system further includes: If the outdoor ambient temperature and the temperature of the heat exchange tube of the outdoor heat exchanger (4) do not simultaneously satisfy the first defrosting condition and the second defrosting condition respectively, obtaining the current indoor temperature; Determine whether the current indoor temperature reaches the preset room temperature set by the user; If the current indoor temperature reaches the preset room temperature set by the user, the air conditioning system is controlled to operate in the main water heating and auxiliary heating mode.

12. The control method of the air conditioning system according to claim 11, characterized in that: The control method of the air conditioning system further includes: If the current indoor temperature does not reach the preset room temperature set by the user, the process returns to the step of controlling the air conditioning system to operate in the main heating and auxiliary water heating modes.

13. The control method of the air conditioning system according to claim 11, characterized in that: The control method of the air conditioning system further includes: After the air conditioning system operates in the main water heating and auxiliary heating mode for a fourth preset time, obtaining the current temperature of hot water in the water tank (7) of the air conditioning system; Determining whether the current temperature of the hot water in the water tank (7) reaches the preset water temperature set by the user; If the current temperature of the hot water in the water tank (7) does not reach the preset water temperature set by the user, the air conditioning system is controlled to continue operating in the main water heating and auxiliary heating mode.

14. The control method of the air conditioning system according to claim 13, characterized in that: The control method of the air conditioning system further includes: If the current temperature of the hot water in the water tank (7) reaches the preset water temperature set by the user, the air conditioning system is controlled to operate in a heating-only mode; After the air conditioning system operates in the heating-only mode for the first preset time, obtaining the outdoor ambient temperature data and the temperature data of the heat exchange tube of the outdoor heat exchanger (4); Determining whether the outdoor ambient temperature and the temperature of the heat exchange tube of the outdoor heat exchanger (4) respectively satisfy the first defrosting condition and the second defrosting condition at the same time; If the outdoor ambient temperature and the temperature of the heat exchange tube of the outdoor heat exchanger (4) respectively satisfy the first defrost condition and the second defrost condition at the same time, the air conditioning system is controlled to operate in the single defrost mode; After the air-conditioning system operates in the defrost-only mode for a third preset time period, the air-conditioning system is controlled to switch to operate in the heating-only mode.

15. The control method of the air conditioning system according to claim 9, characterized in that: When executing the step of obtaining the working mode selected by the user and the preset room temperature set by the user when the air-conditioning system is turned on, the control method of the air-conditioning system further includes: When the user selects the heating-only mode, controlling the air conditioning system to operate in the heating-only mode; After the air conditioning system operates in the heating-only mode for the first preset time, obtaining the outdoor ambient temperature data and the temperature data of the heat exchange tube of the outdoor heat exchanger (4); Determining whether the outdoor ambient temperature and the temperature of the heat exchange tube of the outdoor heat exchanger (4) respectively satisfy the first defrosting condition and the second defrosting condition at the same time; If the outdoor ambient temperature and the temperature of the heat exchange tube of the outdoor heat exchanger (4) respectively satisfy the first defrost condition and the second defrost condition at the same time, the air conditioning system is controlled to operate in the single defrost mode; After the air-conditioning system operates in the defrost-only mode for a third preset time period, the air-conditioning system is controlled to switch to operate in the heating-only mode.

16. The control method of the air conditioning system according to claim 9, characterized in that: When executing the step of obtaining the working mode selected by the user and the preset room temperature set by the user when the air-conditioning system is turned on, the control method of the air-conditioning system further includes: When the user selects the water heating only mode, controlling the air conditioning system to operate in the water heating only mode; After the air conditioning system operates in the water heating mode for the first preset time, obtaining the outdoor ambient temperature data and the temperature data of the heat exchange tube of the outdoor heat exchanger (4); Determining whether the outdoor ambient temperature and the temperature of the heat exchange tube of the outdoor heat exchanger (4) respectively satisfy the first defrosting condition and the second defrosting condition at the same time; If the outdoor ambient temperature and the temperature of the heat exchange tube of the outdoor heat exchanger (4) respectively satisfy the first defrost condition and the second defrost condition at the same time, the air conditioning system is controlled to operate in the single defrost mode; After the air-conditioning system operates in the defrost-only mode for a third preset time period, the air-conditioning system is controlled to switch to operate in the water heating-only mode.

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