Air conditioner

Abstract

An air conditioner (100), comprising a first pipeline (6), a second pipeline (7) and a third pipeline (8), wherein a head end of the first pipeline (6) is connected to a discharge port (51) by means of a first solenoid valve (10), a head end of the second pipeline (7) is connected to the discharge port (51) by means of a second solenoid valve (11), a tail end of the first pipeline (6) and a tail end of the second pipeline (7) are both configured to be connected to a head end of the third pipeline (8), and a tail end of the third pipeline (8) is connected to the discharge port (51) by means of a third solenoid valve (12); a first expansion valve (13), a second expansion valve (14) and a third expansion valve (15); and a first end of a fourth solenoid valve (16) is connected to the third solenoid valve (12) and the tail end of the third pipeline (8), a second end of the fourth solenoid valve (16) is connected to a first end of a fifth solenoid valve (17), a first end of a seventh solenoid valve (19) and a suction port (52), a first end of a sixth solenoid valve (18) is connected to the first solenoid valve (10), and a second end of the sixth solenoid valve (18) is connected to the head end of the first pipeline (6) and to a second end of the seventh solenoid valve (19).

Description

air conditioner

[0001] This application claims priority to Chinese patent application No. 202411464191.7, filed on October 18, 2024; and Chinese patent application No. 202411464188.5, filed on October 18, 2024; and Chinese patent application No. 202411464131.5, filed on October 18, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to the field of air conditioning technology, and in particular to an air conditioner. Background Technology

[0003] In related technologies, air conditioners use a solution of adding a water tank to the refrigeration system to enable the air conditioner to produce domestic hot water while operating in cooling or heating mode. However, in this design, after the refrigerant is discharged from the compressor, it will first pass through the water tank to heat the water in the tank, regardless of the mode of the air conditioner. As a result, the air conditioner may experience problems such as insufficient or excessive cooling or heating capacity. Summary of the Invention

[0004] This disclosure aims to solve the problem of insufficient or excessive cooling or heating capacity in air conditioners caused by the refrigerant preheating the water tank.

[0005] To address the aforementioned problems, an air conditioner is proposed according to some embodiments of this disclosure. The air conditioner includes: a water tank for storing domestic water; a first heat exchanger located outdoors for exchanging heat with 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 regulating indoor temperature; a compressor having an exhaust port and an intake port; a first pipeline, a second pipeline, and a third pipeline, wherein the first end of the first pipeline is connected to the exhaust port via a first solenoid valve, the first end of the second pipeline is connected to the exhaust port via a second solenoid valve, the ends of the first and second pipelines are both connected to the first end of the third pipeline, and the end of the third pipeline is connected to the exhaust port via a third solenoid valve. The first heat exchanger is located on the first pipeline. The system includes: a second heat exchanger located on the second pipeline; a third heat exchanger located on the third pipeline; a first expansion valve, a second expansion valve, and a third expansion valve, wherein the first expansion valve is located on the first pipeline, the second expansion valve is located on the second pipeline, and the third expansion valve is located 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 beginning of the first pipeline and the second end of the seventh solenoid valve; and a controller configured to control the conduction of each solenoid valve and each expansion valve according to the operating mode of the air conditioner.

[0006] According to the air conditioner of this disclosure, three heat exchangers are respectively installed on different pipelines, and seven solenoid valves are installed between each pipeline and the compressor exhaust port to regulate the refrigerant flow. Thus, when the compressor discharges refrigerant, it no longer simply prioritizes the refrigerant through the water tank, but controls the conduction of each solenoid valve and each expansion valve based on the air conditioner's operating mode. This selectively controls the refrigerant discharged at the exhaust port to enter the first pipeline, the second pipeline, and / or the third pipeline. This allows the air conditioner to have multiple different operating modes while avoiding the problem of insufficient or excessive cooling or heating capacity caused by the refrigerant heating the water tank first. Attached Figure Description

[0007] Figure 1 is a structural diagram of an air conditioner according to some embodiments of the present disclosure.

[0008] Figure 2 is a structural diagram of refrigerant flow in an air conditioner according to some embodiments of the present disclosure.

[0009] Figure 3 is a structural diagram of refrigerant flow in an air conditioner according to some embodiments of the present disclosure.

[0010] Figure 4 is a structural diagram of refrigerant flow in an air conditioner according to some embodiments of the present disclosure.

[0011] Figure 5 is a structural diagram of refrigerant flow in an air conditioner according to some embodiments of the present disclosure.

[0012] Figure 6 is another structural diagram of an air conditioner according to some embodiments of the present disclosure.

[0013] Figure 7 is a structural diagram of refrigerant flow in an air conditioner according to some embodiments of the present disclosure.

[0014] Figure 8 is a structural diagram of refrigerant flow in an air conditioner according to some embodiments of the present disclosure. Detailed Implementation

[0015] The following description, in conjunction with the accompanying drawings, clearly and completely describes some embodiments of this disclosure. Obviously, the described embodiments are merely some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments provided in this disclosure are within the scope of protection of this disclosure.

[0016] To address the aforementioned issues, some embodiments of this disclosure provide an air conditioner 100. This air conditioner 100 can achieve not only complete heat recovery of air conditioning waste heat but also partial recovery of air conditioning waste heat, thereby improving the overall energy utilization rate of the air conditioning system, reducing the electricity consumption of the air conditioner 100, and saving electricity costs.

[0017] As shown in Figure 1, in some embodiments, the air conditioner 100 may include a water tank 1 for storing domestic water.

[0018] As shown in Figure 1, in some embodiments, the air conditioner 100 may include a first heat exchanger 2, a second heat exchanger 3, and a third heat exchanger 4. The first heat exchanger 2 is located outdoors and is used for heat exchange of the circulating refrigerant. The second heat exchanger 3 is connected to the water tank 1 and is used for heat exchange of domestic hot water. The third heat exchanger 4 is located indoors and is used to regulate the indoor temperature. That is, the air conditioner can be a tri-generation unit.

[0019] In some embodiments, the air conditioner 100 may include a compressor 5 having an exhaust port 51 and an air inlet 52.

[0020] As shown in Figure 1, in some embodiments, the air conditioner 100 may include a first pipe 6, a second pipe 7, a third pipe 8, a first solenoid valve 10, a second solenoid valve 11, and a third solenoid valve 12. The first end of the first pipe 6 is connected to the exhaust port 51 via the first solenoid valve 10. The first end of the second pipe 7 is connected to the exhaust port 51 via the second solenoid valve 11. The ends of both the first pipe 6 and the second pipe 7 are used to connect to the first end of the third pipe 8. The end of the third pipe 8 is connected to the exhaust port 51 via the third solenoid valve 12. A first heat exchanger 2 is located on the first pipe 6. A second heat exchanger 3 is located on the second pipe 7. A third heat exchanger 4 is located on the third pipe 8.

[0021] As shown in Figure 1, in some embodiments, the air conditioner 100 may include multiple expansion valves. These multiple expansion valves may include a first expansion valve 13, a second expansion valve 14, and a third expansion valve 15. The first expansion valve 13 is disposed on a first pipe 6. The second expansion valve 14 is disposed on a second pipe 7. The third expansion valve 15 is disposed on a third pipe 8.

[0022] As shown in Figure 1, in some embodiments, the air conditioner 100 may include a fourth solenoid valve 16, a fifth solenoid valve 17, a sixth solenoid valve 18, and a seventh solenoid valve 19. 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, respectively. 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 air inlet 52, respectively. 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 beginning of the first pipeline 6 and the second end of the seventh solenoid valve 19, respectively.

[0023] As shown in Figure 1, in some embodiments, the air conditioner 100 may include a controller configured to control the conduction 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 refrigerant to the first heat exchanger 2, the second heat exchanger 3, and the third heat exchanger 4.

[0024] In this embodiment, three expansion valves and seven solenoid valves are connected in parallel and series. When the air conditioner 100 operates in full or partial heat recovery mode, the flow and direction of the refrigerant are changed by controlling the conduction of each expansion valve and each solenoid valve. This allows for both full and partial recovery of air conditioner waste heat. Specifically, the conduction of each solenoid valve and each expansion valve is controlled according to the operating mode of the air conditioner 100. Specifically, depending on whether it is a full or partial heat recovery mode, 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 and direction of the refrigerant. This allows the second heat exchanger 3 to use some or all of the refrigerant to heat the domestic water in the water tank 1, achieving full or partial recovery of waste heat. Therefore, compared to the scheme of using two four-way valves in series and two one-way valves, or one four-way valve and four one-way valves to achieve complete waste heat recovery in related air conditioners, the embodiment of this disclosure adopts a scheme of three expansion valves and seven solenoid valves in parallel and series to more accurately distribute the refrigerant flow in the air conditioner 100. This allows the air conditioner 100 to achieve both complete and partial waste heat recovery, improving the overall energy utilization rate of the air conditioning system, reducing the power consumption of the air conditioner 100, and thus saving electricity costs.

[0025] In some embodiments, if the operating mode of the air conditioner 100 is determined to be the full heat recovery mode, 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 is controlled so that 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 to heat 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 exchanging heat through the third heat exchanger 4, as shown in Figure 2. Alternatively, if the air conditioner 100 is determined to operate in partial heat recovery mode, then by controlling the opening or closing of the first expansion valve 13, second expansion valve 14, third expansion valve 15, first solenoid valve 10, second solenoid valve 11, third solenoid valve 12, fourth solenoid valve 16, fifth solenoid valve 17, sixth solenoid valve 18, and seventh solenoid valve 19, a portion of the high-temperature gaseous refrigerant discharged from the compressor 5 flows into the second heat exchanger 3. This portion 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 a portion of the refrigerant to generate heat to heat the domestic water in the water tank 1. Simultaneously, another portion of the high-temperature gaseous refrigerant discharged from the compressor 5 flows into the first heat exchanger 2 for heat exchange. After exchanging heat with the second heat exchanger 3 and the first heat exchanger, the refrigerant flows back to the compressor 5 through the third heat exchanger 4, as shown in Figure 3. This achieves both total heat recovery and partial heat recovery, improving the overall energy utilization rate of the air conditioning system, reducing the electricity consumption of the air conditioner 100, and thus saving on electricity costs.

[0026] According to the air conditioner of this disclosure embodiment, three heat exchangers are respectively installed on different pipelines, and seven solenoid valves are installed between each pipeline and the compressor exhaust port 51 to regulate the refrigerant flow. Thus, when the compressor discharges refrigerant, it no longer prioritizes the refrigerant to pass through the water tank, but controls the conduction of each solenoid valve and each expansion valve based on the air conditioner's operating mode. This selectively controls the refrigerant discharged at the exhaust port 51 to enter the first pipeline, the second pipeline, and / or the third pipeline. This allows the air conditioner to have multiple different operating modes while avoiding the problem of insufficient or excessive cooling or heating capacity caused by the refrigerant heating the water tank first. Furthermore, based on the parallel and series connection of three expansion valves and seven solenoid valves, when the air conditioner 100 is operating in full or partial heat recovery mode, the flow and direction of the refrigerant are changed by controlling the conduction of each expansion valve and each solenoid valve, thereby achieving full or partial recovery of waste heat. Therefore, compared to the scheme of using two four-way valves in series and two one-way valves, or one four-way valve and four one-way valves to achieve full recovery of waste heat in related air conditioners, the scheme of three expansion valves and seven solenoid valves in parallel and series in this embodiment of the disclosure allows for more precise distribution of the refrigerant flow in the air conditioner 100. This enables the air conditioner 100 to achieve both full and partial recovery of waste heat, improving the overall energy utilization rate of the air conditioning system and reducing the power consumption of the air conditioner 100.

[0027] 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 can be configured to: control the second solenoid valve 11 and the fourth solenoid valve 16 to be open, 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 closed, and control the first expansion valve 13 to be closed, the second expansion valve 14 to be open and the third expansion valve 15 to be open.

[0028] For example, if the air conditioner 100 operates in a simultaneous cooling and hot water production heat recovery mode, then the second solenoid valve 11 and the fourth solenoid valve 16 are both opened, and 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 are all closed. The first expansion valve 13 is closed, the second expansion valve 14 is open, and the third expansion valve 15 is open. At this time, the refrigerant flow direction is as shown in Figure 2. The second heat exchanger 3 uses all the high-temperature gaseous refrigerant discharged from the compressor 5 to heat the water in the water tank 1. After heat exchange, the refrigerant then exchanges heat with the indoor air through the third heat exchanger 4 to lower the indoor temperature, thus realizing the simultaneous cooling and hot water production heat recovery mode of the air conditioner 100. In other words, under the action of the second solenoid valve 11 being open and the first solenoid valve 10 being closed, the high-temperature gaseous refrigerant discharged from the compressor 5 flows entirely 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 to heat the domestic water in the water tank 1, that is, the air conditioner 100 operates in the hot water production full heat recovery mode. After heat exchange, the refrigerant, under the conduction of the second expansion valve 14 and the third expansion valve 15, is throttled and depressurized into low-temperature refrigerant before flowing into 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 and reduce the indoor temperature, thus the air conditioner 100 operates in the cooling mode. Then, after heat exchange, the refrigerant flows into the air inlet 52 of the compressor 5 through the fourth solenoid valve 16 under the action of the third solenoid valve 12, the fifth solenoid valve 17 and the seventh solenoid valve 19 being closed, and the fourth solenoid valve 16 being opened. Thus, the air conditioner 100 achieves complete recovery of waste heat in the cooling mode.

[0029] 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 can be configured to: control the first solenoid valve 10, the second solenoid valve 11, the fourth solenoid valve 16 and the sixth solenoid valve 18 to be open, control the third solenoid valve 12, the fifth solenoid valve 17 and the seventh solenoid valve 19 to be closed, and control the first expansion valve 13, the second expansion valve 14 and the third expansion valve 15 to be open, when the operating mode is a heat recovery mode for simultaneous cooling and hot water production.

[0030] For example, when the air conditioner 100 operates in a partial heat recovery mode that simultaneously cools and heats water, the controller opens the first solenoid valve 10, the second solenoid valve 11, the fourth solenoid valve 16, and the sixth solenoid valve 18, closes the third solenoid valve 12, the fifth solenoid valve 17, and the seventh solenoid valve 19, and opens the first expansion valve 13, the second expansion valve 14, and the third expansion valve 15. At this time, the refrigerant flow direction is as shown in Figure 3. That is, under the action of the opening of the first solenoid valve 10 and the second solenoid valve 11, part of the high-temperature gaseous refrigerant discharged from the compressor 5 flows into the second heat exchanger 3 through the second solenoid valve 11. 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 to heat the domestic water in the water tank 13. That is, the air conditioner 100 operates in a partial heat recovery mode for hot water production. The refrigerant after heat exchange with the second heat exchanger 3 is throttled and depressurized to a low-temperature refrigerant through the second expansion valve 14 of the second pipeline 7. Simultaneously, another part of the high-temperature gaseous refrigerant discharged from the compressor 5 is throttled and depressurized through the second expansion valve 14 of the second pipeline 7. With the opening of valve 10 and the sixth solenoid valve 18, refrigerant flows into the first heat exchanger 2 through the first solenoid valve 10 and the sixth solenoid valve 18. The first heat exchanger is located outdoors. The first heat exchanger 2 exchanges some of the refrigerant with the outdoor air, that is, the refrigerant releases heat to the outdoor air to exchange heat with the circulating refrigerant. After exchanging heat with the first heat exchanger 2, the refrigerant, under the action of the opening of the first expansion valve 13, passes through the first expansion valve 13 of the first pipeline 6 and is throttled and depressurized to become low-temperature refrigerant. The low-temperature refrigerant that converges at the end of the first pipeline 6 and the second pipeline 7 passes through... The third expansion valve 15 throttles and reduces pressure, and the low-temperature refrigerant, after further cooling, 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 and reduce the indoor temperature. Thus, the air conditioner 100 operates in cooling mode. Then, the refrigerant after heat exchange flows into the air inlet 52 of the compressor 5 through the fourth solenoid valve 16 under the action of the third solenoid valve 12 and the seventh solenoid valve 19 being closed and the fourth solenoid valve 16 being opened. Thus, the air conditioner 100 achieves partial recovery of waste heat in the cooling mode.

[0031] In some embodiments, the controller can also be configured to: control the compressor 5 to start when the outdoor ambient temperature is within the normal operating range of the compressor 5, the heat exchange temperature of the third heat exchanger 4 is greater than the first preset temperature, and the off-time of the compressor 5 reaches a preset duration, so that the air conditioner 100 operates in cooling mode; and control the compressor 5 to start when the outdoor ambient temperature is within the normal operating range of the compressor 5, the domestic water temperature is lower than the second preset temperature, and the off-time of the compressor 5 reaches a preset duration, so that the air conditioner 100 operates in hot water production mode. The hot water production mode includes a total heat recovery mode and a partial heat recovery mode. When the outdoor ambient temperature is within the normal operating range of the compressor 5, the heat exchange temperature of the third heat exchanger 4 is greater than the first preset temperature, the domestic water temperature is lower than the second preset temperature, and the off-time of the compressor 5 reaches a preset duration, control the compressor 5 to start, so that the air conditioner 100 operates in simultaneous cooling and hot water production mode.

[0032] The first preset temperature can be understood as a pre-set temperature value used to determine whether the indoor environment requires the air conditioner 100 to operate in cooling mode for adjustment; the first preset temperature can be 5℃. The preset duration can be understood as the threshold duration for determining whether the compressor 5 has not started; the preset duration can be 3 minutes. The second preset temperature can be understood as a pre-set temperature value used to determine whether domestic hot water needs to be heated; the second preset temperature can be 55℃. When the third heat exchanger 4 is a plate heat exchanger, the heat exchange temperature is the outlet water temperature of the plate heat exchanger.

[0033] For example, operating compressor 5 at extreme outdoor temperatures may affect its lifespan and increase the risk of malfunction. When the outdoor temperature is within its normal operating range, compressor 5 can start and operate normally, maintaining high efficiency. However, when the indoor temperature is high, the heat exchange temperature between the indoor environment and the third heat exchanger 4 will be high. Furthermore, if the compressor 5's off-time is less than the preset duration, the air conditioner 100 may start, but compressor 5 may have briefly stopped due to special circumstances. Therefore, when the outdoor temperature is within compressor 5's normal operating range, it indicates that compressor 5 can start and operate normally, maintaining high efficiency. If the heat exchange temperature of the third heat exchanger 4 is greater than the first preset temperature, it indicates that the indoor temperature is high, and air conditioner 100 needs to operate in cooling mode. Conversely, if the compressor 5's off-time reaches the preset duration, it indicates that compressor 5 has not started and air conditioner 100 is not operating. Therefore, compressor 5 is controlled to start, allowing air conditioner 100 to operate in cooling mode. Therefore, in this embodiment, the air conditioner 100 is determined to be in cooling mode by the heat exchange temperature of the third heat exchanger 4, and the outdoor ambient temperature and the shutdown time of the compressor 5 are determined to meet the requirements, so as to ensure that the compressor 5 can start normally and effectively improve the service life and working efficiency of the compressor 5.

[0034] When the outdoor ambient temperature is within the normal operating range of compressor 5, it indicates that compressor 5 can start and operate normally and maintain a high-efficiency working state. If the domestic water temperature is lower than the second preset temperature, it indicates that the domestic water temperature is low, and air conditioner 100 needs to operate in hot water mode. When the compressor 5's off-time reaches the preset duration, it indicates that compressor 5 has not started and air conditioner 100 is in a non-working state. Compressor 5 is then controlled to start, allowing air conditioner 100 to operate in hot water mode. The hot water mode includes a total heat recovery mode and a partial heat recovery mode. Therefore, in this embodiment, the domestic water temperature is used to determine whether air conditioner 100 operates in hot water mode, while simultaneously ensuring that the outdoor ambient temperature and compressor 5's off-time meet the requirements, thus ensuring that compressor 5 can start normally and effectively improving the compressor 5's service life and operating efficiency.

[0035] When the outdoor ambient temperature is within the normal operating range of compressor 5, it indicates that compressor 5 can start and operate normally and maintain a high-efficiency working state. If the heat exchange temperature of the third heat exchanger 4 is greater than the first preset temperature, it indicates that the indoor ambient temperature is high, and the air conditioner needs to operate in cooling mode. If the domestic water temperature is lower than the second preset temperature, it indicates that the domestic water temperature is low, and the air conditioner 100 needs to operate in hot water mode. When the compressor 5's off-time reaches the preset time, it indicates that compressor 5 has not started and the air conditioner 100 is in a non-working state. The compressor 5 is then started, allowing the air conditioner 100 to operate in simultaneous cooling and hot water production mode. Therefore, in this embodiment, the simultaneous cooling and hot water production mode of the air conditioner 100 is determined by the heat exchange temperature of the third heat exchanger 4 and the domestic water temperature. Simultaneously, the outdoor ambient temperature and the compressor 5's off-time are determined to meet the requirements, ensuring that compressor 5 can start normally and effectively improving the service life and working efficiency of compressor 5.

[0036] Furthermore, it should be noted that compressor 5 must not be started when the outdoor ambient temperature is outside its normal operating range. The normal operating range is between -25℃ and 48℃. If the heat exchange temperature of the third heat exchanger is lower than the first preset temperature, then the cooling mode does not need to be run.

[0037] In some embodiments, after the compressor 5 is started, the controller is further configured to perform the following steps: Step S101, determining a first temperature difference between the domestic water temperature and the target water temperature, and determining a second temperature difference between the heat exchange temperature of the third heat exchanger and the target heat exchange temperature. Step S102, controlling the variation range of the operating frequency of the compressor 5 according to the first temperature difference and the second temperature difference.

[0038] In some embodiments, compressor 5 starts at an initial frequency f. The initial frequency f is generally between 25 and 40 Hz. After starting, compressor 5 runs at the initial frequency f for 3 minutes. After 3 minutes, the operating frequency of compressor 5 is controlled according to a first temperature difference and a second temperature difference. The target water temperature is the domestic water temperature set by the user according to their needs.

[0039] For example, 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 temperature set by the user according to their needs. In this case, it is necessary to control the compressor 5 to operate at a higher frequency to increase the refrigerant flow into the second heat exchanger 3, so that the refrigerant can perform more efficient heat exchange with the domestic water, thereby quickly raising the domestic water temperature. Moreover, the lower the first temperature difference, the higher the fluctuation range of the compressor 5's operating frequency. Furthermore, if the second temperature difference between the heat exchange temperature of the third heat exchanger 4 and the target heat exchange temperature is smaller, it indicates a greater cooling demand, and the fluctuation range of the compressor 5's operating frequency is also higher. Based on this, in order to balance cooling and hot water production needs when controlling the operating frequency of the compressor 5, this embodiment of the disclosure uses the first temperature difference... The operating frequency of compressor 5 is controlled by the first and second temperature differences. In other words, the cooling and hot water production demands are determined by the first and second temperature differences. Then, the operating frequency of compressor 5 is selected to meet these demands, and the frequency is controlled accordingly. For example, when both the first and second temperature differences are large, it indicates that the air conditioner 100 needs both rapid heating of domestic water and efficient cooling. In this case, the operating frequency of compressor 5 is controlled at a high level to simultaneously meet both cooling and hot water production demands. Conversely, when both the first and second temperature differences are small, the operating frequency of compressor 5 is controlled at a low level to simultaneously meet both cooling and hot water production demands, avoiding excessive adjustment and energy waste. Therefore, in this embodiment, the operating frequency of compressor 5 is dynamically adjusted based on cooling and hot water production demands, thereby balancing the cooling and hot water production needs of the air conditioner and improving the overall system efficiency and user experience.

[0040] In some embodiments, a correspondence between the first temperature difference and the second temperature difference and a preset change range of the compressor 5 operating frequency can be preset in the controller, thereby obtaining the corresponding preset change range through the first temperature difference and the second temperature difference.

[0041] Table 1

[0042] As shown in Table 1, the frequency variation of compressor 5 with ΔT1 ≤ -8 is higher than that with -1 < ΔT1 < 0, and the frequency variation of compressor 5 with ΔT2 ≥ 8 is higher than that with -1 ≤ ΔT2 < -0.5. When ΔT1 ≥ 0, it indicates that the domestic water temperature has reached the temperature set by the user, so there is no need to increase the operating frequency of compressor 5 to heat the domestic water; in this case, the frequency variation of compressor 5 is controlled only based on the second temperature difference. When ΔT2 < -2, there is no cooling demand, so there is no need to increase the operating frequency of compressor 5 to increase the cooling capacity; in this case, the frequency variation of compressor 5 is controlled only based on the first temperature difference. When the first temperature difference ΔT1 is the same, the larger the second temperature difference ΔT2, the greater the frequency variation of compressor 5. Conversely, when the second temperature difference ΔT2 is the same, the larger the first temperature difference ΔT1, the greater the frequency variation of compressor 5.

[0043] For example, by looking up Table 1 through the first temperature difference ΔT1 and the second temperature difference ΔT2, the change range of the operating frequency of the compressor 5 can be obtained. If the first temperature difference ΔT1 ≤ -8 and the second temperature difference ΔT2 ≥ 8, the change range of the operating frequency of the compressor 5 is +8.

[0044] In some embodiments, when controlling the first expansion valve 13 in the hot water production section heat recovery mode, the controller may also be configured to perform the following steps: Step S103, determining a third temperature difference between the coil temperature of the first heat exchanger and the outdoor ambient temperature. Step S104, determining a first opening increment of the first expansion valve 13 based on the third temperature difference. Step S105, adjusting the opening of the first expansion valve 13 based on the first opening increment.

[0045] For example, 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 at the outlet of the first heat exchanger 2. When the third temperature difference is lower than the lower limit of the temperature difference range corresponding to the superheat setting requirement, the superheat at the outlet of the first heat exchanger 2 is insufficient. In other words, if the refrigerant flow rate in the first heat exchanger 2 is too high, the refrigerant residence time in the first heat exchanger 2 is relatively short, and the refrigerant cannot fully exchange heat with the first heat exchanger 2. At this time, the opening 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 at the outlet of the first heat exchanger 2 to ensure that the superheat at the outlet of the first heat exchanger 2 meets the requirements. When the third temperature difference is higher than the upper limit of the temperature difference range corresponding to the superheat setting requirement, the superheat at the outlet of the first heat exchanger 2 is too high. In other words, if the refrigerant flow rate in the first heat exchanger 2 is too low, the refrigerant residence time in the first heat exchanger 2 is relatively long, and the refrigerant can fully exchange heat with the first heat exchanger 2. At this time, the opening of the first expansion valve 13 needs to be increased to increase the refrigerant flow rate. Based on this, to ensure the efficient and stable operation of the first heat exchanger 2, in this embodiment, when controlling the first expansion valve 13 in the heat recovery mode of the hot water production section, the first opening increment of the first expansion valve 13 is determined according to the third temperature difference. This first opening increment changes the outlet superheat of the first heat exchanger 2, ensuring that the outlet superheat of the first heat exchanger 2 meets the set requirements. Specifically, when the third temperature difference is lower than the lower limit of the temperature difference range corresponding to the superheat setting requirement, the first opening increment is controlled to be negative, i.e., the opening of the first expansion valve 13 is reduced. Furthermore, the higher the third temperature difference, the larger the first opening increment, thereby increasing the outlet superheat of the first heat exchanger 2 through the magnitude of the third temperature difference, ensuring that the outlet superheat of the first heat exchanger 2 meets the requirements. When the third temperature difference is higher than the upper limit of the temperature difference range corresponding to the superheat setting requirement, the first opening increment is controlled to be positive, i.e., the opening of the first expansion valve 13 is increased, decreasing the outlet superheat of the first heat exchanger 2, ensuring that the outlet superheat of the first heat exchanger 2 meets the requirements.

[0046] For example, when the domestic water temperature is higher than the second preset temperature, the opening 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 increment of the first expansion valve 13 is determined based on the third temperature difference. The third temperature difference is denoted as Tg-Th. When Tg-Th satisfies 10℃≤Tg-Th<15℃, the superheat of the first heat exchanger 2 meets the set requirements. If Tg-Th≤5℃, the first opening increment ΔD is -5. If 5℃<Tg-Th<10℃, the first opening increment ΔD1 is -2. If 10℃≤Tg-Th<15℃, the first opening increment ΔD1 is 0. If Tg-Th≥15℃, the first opening increment ΔD1 is +2. Furthermore, it should be noted that the opening of the first expansion valve 13 needs to be adjusted every 40 seconds.

[0047] 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 remains at 0 steps.

[0048] In some embodiments, when controlling the second expansion valve 14 in hot water production mode, the controller may also be configured to perform the following steps: Step S106, obtaining the condensation temperature of the refrigerant and determining a fourth temperature difference between the condensation temperature and the domestic water temperature. Step S107, determining a second opening increment of the second expansion valve 14 based on the domestic water temperature and the fourth temperature difference. Step S108, adjusting the opening of the second expansion valve 14 based on the second opening increment.

[0049] For example, when the second heat exchanger 3 uses the refrigerant discharged from the compressor 5 to heat the domestic water in the water tank 1, if the opening of the second expansion valve 14 decreases and the increment of the opening of the second expansion valve 14 is smaller, the flow rate of the refrigerant discharged from the second heat exchanger 3 will decrease, so that the refrigerant can fully exchange heat with the domestic water to enhance the temperature rise of the domestic water. If the opening of the second expansion valve 14 increases and the increment of the opening of the second expansion valve 14 is larger, the flow rate of the refrigerant discharged from the second heat exchanger 3 will increase, so as to slow down the temperature rise of the domestic water. The superheat of the second heat exchanger 3 is determined by the fourth temperature difference between the condensing temperature and the domestic water temperature. When the fourth temperature difference is lower than the lower limit of the temperature difference range corresponding to the superheat setting requirement, the superheat at the outlet of the second heat exchanger 3 is insufficient. In other words, the refrigerant flow rate in the second heat exchanger 3 is too high, and the refrigerant residence time in the second heat exchanger 3 is relatively short, so the refrigerant cannot fully exchange heat with the second heat exchanger 3. At this time, the opening of the second expansion valve 14 needs to be reduced to reduce the refrigerant flow rate, so that the refrigerant can fully exchange heat with the second heat exchanger 3 and increase the superheat at the outlet of the second heat exchanger 3 to meet the requirements. When the fourth temperature difference is higher than the upper limit of the temperature difference range corresponding to the superheat setting requirement, the superheat at the outlet of the second heat exchanger 3 is too high. In other words, the refrigerant flow rate in the second heat exchanger 3 is too low, and the refrigerant residence time in the second heat exchanger 3 is relatively long, so the refrigerant can fully exchange heat with the second heat exchanger 3. At this time, the opening of the second expansion valve 14 needs to be increased to increase the refrigerant flow rate. Based on this, in order to achieve precise control of the superheat of the second heat exchanger 3 and to raise the temperature of domestic water, the second opening increment of the second expansion valve 14 is determined according to the domestic water temperature and the fourth temperature difference. This second opening increment changes the outlet superheat of the second heat exchanger 3 to ensure that the outlet superheat of the second heat exchanger 3 meets the set requirements. Simultaneously, the second opening increment also alters the domestic water heating effect, ensuring that the domestic water temperature reaches the user-set temperature. Specifically, when the fourth temperature difference is lower than the lower limit of the temperature difference range corresponding to the superheat setting requirement, the second opening increment is controlled to be negative, and the higher the fourth temperature difference, the larger the second opening increment. This increases the outlet superheat of the second heat exchanger 3 by adjusting the magnitude of the fourth temperature difference, ensuring that the outlet superheat of the second heat exchanger 3 meets the requirements. When the fourth temperature difference is higher than the upper limit of the temperature difference range corresponding to the superheat setting requirement, the second opening increment is controlled to be positive, reducing the outlet superheat of the second heat exchanger 3 to ensure that the outlet superheat of the second heat exchanger 3 meets the requirements. Meanwhile, if it is determined that the lower the domestic water temperature, the negative the second opening increment is, and the smaller the second opening increment is, the better the domestic water temperature rise effect is. Therefore, in this embodiment, the second opening 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 of the second heat exchanger 3 and achieve the heating of domestic water.

[0050] In some embodiments, the correspondence 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, thereby obtaining the corresponding second opening increment through the domestic water temperature and the fourth temperature difference.

[0051] As shown in Table 2, the second opening increment ΔD2 when Tn-Tx ≤ 0 is lower than the second opening increment ΔD2 when 0 < Tn-Tx < 5. When Tn-Tx satisfies 10℃ ≤ Tn-Tx < 15℃, the superheat of the second heat exchanger 3 meets the set requirements. Under the same Tn-Tx conditions, the second opening increment ΔD2 when Tx < 45℃ is lower than the second opening increment ΔD2 when 53 ≤ Tx, meaning that under the same Tn-Tx conditions, the larger Tx is, the larger the second opening increment ΔD2 is.

[0052] Table 2

[0053] In some embodiments, the fourth temperature difference can be expressed as condensation temperature Tn - domestic water temperature Tx. The second opening increment ΔD2 is obtained by referring to the table in Table 2 using domestic water temperature Tx and Tn-Tx. For example, if Tn-Tx≤0 and 45≤Tx<50℃, then the second opening increment ΔD2 is -4.

[0054] In some embodiments, when controlling the third expansion valve 15 in simultaneous cooling and hot water production mode, the controller can also be configured to: acquire the liquid pipe temperature of the third heat exchanger, the discharge temperature of the compressor 5, 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 15 based on the discharge temperature and the fifth temperature difference; and adjust the opening of the third expansion valve 15 based on the third opening increment. The temperature of the refrigerant in the refrigerant-side connecting pipe of the plate heat exchanger is also considered.

[0055] For example, the discharge temperature of compressor 5 indicates the low-pressure level of the refrigeration system. When the low-pressure level is too high or too low, the refrigeration system becomes increasingly unstable. In this case, the opening of the third expansion valve 15 needs to be adjusted to change the refrigerant flow rate and thus regulate the low-pressure level. Furthermore, the superheat of the third heat exchanger is determined by the fifth temperature difference between the inlet water temperature and the liquid pipe temperature. When this fifth temperature difference is lower than the lower limit of the temperature difference range corresponding to the superheat setting requirement, the superheat at the outlet of the third heat exchanger is insufficient. In other words, the refrigerant flow rate inside the third heat exchanger is too high, resulting in a relatively short residence time for the refrigerant, preventing sufficient heat exchange. In this case, the opening of the third expansion valve 15 needs to be reduced to decrease the refrigerant flow rate, allowing for more thorough heat exchange with the third heat exchanger and increasing the superheat at the outlet of the third heat exchanger to meet the requirements. Based on this, in order to achieve precise control of the superheat of the third heat exchanger and balance the low-pressure of the refrigeration system, in this embodiment, the third opening increment of the third expansion valve 15 is determined according to the exhaust temperature and the fifth temperature difference. This third opening increment changes the outlet superheat of the third heat exchanger to ensure that the outlet superheat meets the set requirements. Specifically, when the fifth temperature difference is lower than the set requirement, the second opening increment is controlled to be negative, and the higher the fifth temperature difference, the larger the third opening increment. This increases the outlet superheat of the third heat exchanger by controlling the magnitude of the fifth temperature difference, ensuring that the outlet superheat meets the requirements. When the fifth temperature difference is lower than the lower limit of the temperature difference range corresponding to the superheat setting requirement, the third opening increment is controlled to be negative, and the higher the fifth temperature difference, the larger the third opening increment. This increases the outlet superheat of the third heat exchanger by controlling the magnitude of the fifth temperature difference, ensuring that the outlet superheat meets the requirements. Simultaneously, the third opening increment changes the low-pressure of the refrigeration system to balance the low-pressure of the refrigeration system.

[0056] In some embodiments, the correspondence between the exhaust temperature and the fifth temperature difference and the third opening increment of the third expansion valve 15 can be preset in the controller, thereby obtaining the corresponding third opening increment through the exhaust temperature and the fifth temperature difference.

[0057] In some embodiments, as shown in Table 3 below, when Tj-Ty satisfies Tj-Ty≥2, the superheat of the third heat exchanger meets the set requirements. The third opening increment of 0<Tj-Ty<2 is greater than the third opening increment of Tj-Ty≤0, that is, the larger Tj-Ty is, the higher the third opening increment. Under the same Tj-Ty conditions, the third opening increment of Tp<90℃ is less than the third opening increment of 90≤Tp<95℃ is less than the third opening increment of 95≤Tp, that is, under the same Tj-Ty conditions, the larger Tp is, the higher the third opening increment.

[0058] Table 3

[0059] In some embodiments, the fifth temperature difference can be represented as Tj-Ty, and the third opening increment ΔD3 can be obtained by referring to the table in Table 3 using the exhaust temperature Tp and Tj-Ty. For example, if Tj-Ty ≥ 2 and Tp < 90°C, then the third opening increment ΔD3 is 0.

[0060] In some embodiments, when the first expansion valve 13, the second expansion valve 14, and the third expansion valve 15 interact and cause fluctuations, control is performed according to the rules in Table 4 below.

[0061] Table 4

[0062] In some embodiments, after the air conditioning unit is powered on, the first expansion valve, the second expansion valve, and the third expansion valve perform a reset action, opening for 480 steps, then closing for 540 steps, and then opening back to the initial number of steps. The three expansion valves operate simultaneously, and the expansion valves can be electronic expansion valves.

[0063] The initial steps for the expansion valve are shown in Table 5 below:

[0064] Table 5

[0065] In some embodiments, the air conditioner 100 may further include an outdoor fan 201, which is located at the first heat exchanger 2. The outdoor fan 201 can introduce fresh outdoor air into the room to improve indoor air quality. The controller may also be configured to: control the outdoor fan 201 to turn off in the hot water full heat recovery mode; and in the hot water partial heat recovery mode, determine a sixth temperature difference between the condensing temperature of the refrigerant and the coil temperature of the first heat exchanger 2, and control the speed of the outdoor fan 201 according to the sixth temperature difference.

[0066] For example, in order to precisely control the speed of the outdoor fan 201, in this embodiment of the disclosure, the speed of the outdoor fan 201 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 requirements are determined by the sixth temperature difference, and the speed of the outdoor fan 201 is adjusted according to the indoor ventilation requirements, thereby precisely controlling the speed of the outdoor fan 201, effectively solving the indoor ventilation problem, and improving indoor air quality.

[0067] In some embodiments, for controlling the speed of the outdoor fan 201 based on the sixth temperature difference, the controller can be configured to: if the sixth temperature difference is higher than the first temperature difference threshold, control the speed of the outdoor fan 201 to decrease; if the sixth temperature difference is lower than the second temperature difference threshold, control the speed of the outdoor fan 201 to increase, wherein the first temperature difference threshold is greater than the second temperature difference threshold.

[0068] For example, if the sixth temperature difference is higher than the first temperature difference threshold, it indicates that less fresh air is needed indoors, so the speed of the outdoor fan 201 is reduced; if the sixth temperature difference is lower than the second temperature difference threshold, it indicates that more fresh air is needed indoors, so the speed of the outdoor fan 201 is increased. Therefore, in this embodiment, the speed of the outdoor fan 201 is controlled by the sixth temperature difference between the condensation temperature of the refrigerant and the coil temperature of the first heat exchanger 2, thereby precisely controlling the speed of the outdoor fan 201, effectively solving the indoor ventilation problem, and improving indoor air quality.

[0069] For example, in the heat recovery mode of the hot water production section, the sixth temperature difference Tn-Tg is controlled to satisfy 3℃≤Tn-Tg≤5℃. If Tn-Tg>5℃, the speed of the outdoor fan 201 is reduced. If Tn-Tg<3℃, the speed of the outdoor fan 201 is increased.

[0070] In some embodiments, as shown in Figures 1 and 2, the air conditioner 100 may include 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 3 and the water tank 1, heating the water to produce domestic hot water. The second water pump 21 delivers cold and hot water to the user, thereby lowering or raising the temperature of the user's room.

[0071] In some embodiments, in hot water production mode, the coil temperature Tg of the first heat exchanger 2 is controlled to satisfy 5 ≤ Tg ≤ 12℃. If Tg > 12℃, the speed of the outdoor fan 201 is reduced; if Tg < 5℃, the speed of the outdoor fan 201 is increased. Alternatively, in cooling mode, the coil temperature of the first heat exchanger 2 is controlled to satisfy 35 ≤ Tg ≤ 45℃. If Tg < 35℃, the speed of the outdoor fan 201 is reduced; if Tg > 45℃, the speed of the outdoor fan 201 is increased.

[0072] In some embodiments, the control process of the first water pump 20 is as follows: After the air conditioner 100 is turned on, the first water pump 20 starts at its maximum speed and detects the status of the water flow switch. If the water flow switch is detected to be open for 15 consecutive seconds, it indicates that the water flow is too low, and the first water pump 20 stops operating. Also, when the domestic water temperature Tx - the second preset temperature ≥ 0℃, the first water pump 20 shuts off after a 1-minute delay. When controlling the speed of the first water pump 20, the first water pump 20 maintains the outlet and inlet water temperatures of the second heat exchanger 3 at 4℃ ≤ outlet temperature - inlet temperature ≤ 6℃. If the outlet temperature - inlet temperature < 4℃, the speed of the first water pump 20 decreases, and the duty cycle decreases by 10% per minute, adjusting once per minute; if the outlet temperature - inlet temperature > 6℃, the speed of the first water pump 20 increases, and the duty cycle increases by 10% per minute, adjusting once per minute.

[0073] In some embodiments, the control process of the second water pump 21 is as follows: After the air conditioner 100 is turned on, the second water pump 21 starts at its maximum speed and detects the status of the water flow switch. If the water flow switch is detected to be open for 15 consecutive seconds, it indicates that the water flow is too low, and the second water pump 21 stops operating. When the heat exchange temperature of the third heat exchanger 4 minus the first preset temperature is greater than 5°C, the second water pump 21 restarts.

[0074] When the heat exchange temperature of the third heat exchanger 4 minus the first preset temperature is ≤ -2℃, the second water pump operates on a 2-minute on-time and 2-minute off-time cycle. After the air conditioner 100 is turned off, the second water pump shuts off after a 2-minute delay.

[0075] When controlling the speed of the second water pump 21, the second water pump 21 operates to maintain the outlet water temperature and inlet water temperature of the second heat exchanger 3 to meet the condition that 4℃ ≤ inlet water temperature - outlet water temperature ≤ 6℃. If the inlet water temperature - outlet water temperature < 4℃, the speed of the second water pump 21 decreases, and the duty cycle decreases by 10% per minute, and is adjusted once per minute. If the inlet water temperature - outlet water temperature > 6℃, the speed of the second water pump 21 increases, and the duty cycle increases by 10% per minute, and is adjusted once per minute.

[0076] Based on the above architecture, the air conditioner 100 disclosed herein can also be used to avoid the problem of the compressor failing to start in extremely low temperature environments. In related air conditioners, when the compressor starts in low temperature environments, the heat source is a single air side. This starting method results in a slow rise in compressor oil temperature, and may even lead to the problem of the compressor failing to start.

[0077] To address the aforementioned issues, the air conditioner 100 provided in this embodiment can rapidly raise the compressor oil temperature by using a water tank as a heat source when the compressor starts, thereby improving the compressor's reliability and avoiding the problem of the compressor failing to start in extremely low temperature environments.

[0078] In some embodiments, as shown in FIG1, the air conditioner 100 may include 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, and a control valve.

[0079] The system includes a water tank 1 for storing domestic water. A first heat exchanger 2, located outdoors, exchanges heat with the circulating refrigerant. A second heat exchanger 3, connected to the water tank, exchanges heat with the domestic water. A third heat exchanger 4, located indoors, regulates the indoor temperature. A compressor 5 has an exhaust port 51 and an inlet port 52. The beginnings of the first pipe 6 and the second pipe 7 are both connected to the exhaust port 51. The ends of the first pipe 6 and the second pipe 7 are both connected to the beginning of the third pipe 8. The end of the third pipe 8 is connected to the exhaust port 51. The first heat exchanger 2 is located on the first pipe 6. The second heat exchanger 3 is located on the second pipe 7. The third heat exchanger 4 is located on the third pipe 8. A control valve is located between the exhaust port 51 and the beginnings of the first pipe 6, the second pipe 7, the third pipe 8, and the inlet port 52. The control valve changes the flow direction of the refrigerant discharged from the exhaust port 51. A controller is connected to the control valve.

[0080] Based on the architecture of the air conditioner 100 described above, the controller of the air conditioner is configured to perform the following steps S201-S202.

[0081] Step S201: Start the heating mode and determine that the outdoor ambient temperature is lower than the first preset temperature.

[0082] For example, the outdoor ambient temperature can be acquired by a sensor and sent to the controller. When the air conditioner 100 is operating in heating mode, the compressor 5 needs to absorb heat from a heat source to increase its oil temperature. In related technologies, outdoor air is used as a heat source. However, in extremely low-temperature environments, it is difficult to obtain heat from outdoor air, which may prevent the compressor 5 from starting. Therefore, if the outdoor temperature is determined to be lower than a first preset temperature, the outdoor air as a heat source may not provide enough heat, preventing the compressor 5 from starting. In this case, the water tank should be used as a heat source to ensure that the compressor 5 can start quickly. Conversely, if the outdoor temperature is determined to be no lower than the first preset temperature, the outdoor air as a heat source can ensure that the compressor 5 starts normally, and the water tank is not needed. The first preset temperature is a preset critical value used to control the compressor's inability to start when using air as a heat source. For example, the first preset temperature can be set to -10℃, -20℃, -30℃, etc.

[0083] In step S202, during the heating start-up phase of the heating mode, the opening and closing of the control valve are controlled to guide the refrigerant discharged from the exhaust port 51 through the third pipeline and the second pipeline in sequence before entering the air inlet 52.

[0084] To solve the above problems, when the air conditioner 100 is in the heating mode and in the heating start-up stage, that is, when the compressor 5 starts, it needs to absorb heat from the heat source. By controlling the opening and closing of the control valve, the refrigerant is guided through the second pipe 7 so that the refrigerant can exchange heat with the domestic water in the water tank 1. Thus, the water tank 1 is used as a heat source to ensure that the compressor 5 can start normally under low temperature conditions.

[0085] In some embodiments, as shown in FIG4, 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 start-up stage of the heating mode, the refrigerant is discharged through the exhaust port 51 of the compressor 5 and then passes through the third pipeline 8. It exchanges heat in the third heat exchanger 4 on the third pipeline 8, and then passes through the second pipeline 7. It exchanges heat with the domestic water in the water tank 1 in the second heat exchanger 3 on the second pipeline 7. After obtaining sufficient heat, it returns to the compressor 5 through the air inlet 52 of the compressor 5, thereby establishing a pressure difference for the refrigeration system and rapidly increasing the oil temperature of the compressor 5. This enables the compressor 5 to start at low temperature and improves the reliability of the compressor 5.

[0086] According to the air conditioner 100 of this disclosure, the operating mode of the air conditioner 100, i.e. the operating condition of the compressor 5, controls the conduction of the control valve and uses the water tank as the heat source for starting the compressor 5. Thus, the scheme of the first pipeline 6, the second pipeline 7, the third pipeline 8 and the control valve in this disclosure is used to more accurately distribute the flow of refrigerant in the air conditioner 100. This allows the air conditioner to use the water tank 1 as a heat source to quickly raise the oil temperature of the compressor 5 when the compressor 5 starts, thereby improving the reliability of the compressor and avoiding the problem of the compressor 5 failing to start in extremely low temperature environments.

[0087] In some embodiments, as shown in FIG4, the air conditioner 100 may further include a first expansion valve 13, a second expansion valve 14, and a third expansion valve 15. The control valve may 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.

[0088] The system comprises the following components: a first expansion valve 13 is mounted on the first pipeline 6; a second expansion valve 14 is mounted on the second pipeline 7; a third expansion valve 15 is mounted on the third pipeline 8; a first solenoid valve 10 is located between the exhaust port 51 and the first end of the sixth solenoid valve 18; a second solenoid valve 11 is located between the exhaust port 51 and the beginning of the second pipeline 7; a second solenoid valve 11 is located between the exhaust port 51 and the end of the third pipeline 8; a fourth solenoid valve 16 is connected to the first end of the third solenoid valve 12 and the end of the third pipeline 8; a 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 air inlet 52; and a sixth solenoid valve 18 is connected to the beginning of the first pipeline 6 and the second end of the seventh solenoid valve 19.

[0089] To address the aforementioned issues, this disclosure employs a control valve configuration consisting of 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, connected in series or parallel with a first expansion valve 13, a second expansion valve 14, and a third expansion valve 15. This allows the air conditioner 100 to enter its heating start-up phase when the outdoor ambient temperature is below a first preset temperature. The control valves 10, 11, 12, 16, 17, 18, and 19 are then connected to the first expansion valves 13, 14, and 15 to guide the refrigerant through the second pipeline 7. This enables the refrigerant to exchange heat with the domestic water in the water tank 1, thereby utilizing the water tank 1 as a heat source to ensure the compressor 5 can start normally under low-temperature conditions.

[0090] In some embodiments, as shown in FIG4, if the outdoor ambient temperature is determined to be lower than the first preset temperature, the air conditioner 100 is in the heating start-up stage of the heating mode. The conduction status of 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, the seventh solenoid valve 19, the first expansion valve 13, the second expansion valve 14, and the third expansion valve 15 is controlled so that the refrigerant is discharged through the exhaust port 51 of the compressor 5 and passes through the third pipeline 8. Heat exchange occurs in the third heat exchanger 4 on the third pipeline 8, and then passes through the second pipeline 7. Heat exchange occurs with the domestic water in the water tank 1 in the second heat exchanger 3 on the second pipeline 7. After obtaining sufficient heat, it returns to the compressor 5 through the air inlet 52 of the compressor 5, thereby establishing a pressure difference for the refrigeration system and rapidly increasing the oil temperature of the compressor 5. This achieves low-temperature start-up of the compressor 5 and improves the reliability of the compressor 5.

[0091] In some embodiments, the control valve is configured to control the opening of the control valve to guide the refrigerant discharged from the exhaust port 51 through the third pipe 8 and the second pipe 7 sequentially into the intake port 52. The controller can be configured to control the second expansion valve 14 and the third expansion valve 15 to open and control the first expansion valve 13 to close; control the third solenoid valve 12 and the fifth solenoid valve 17 to open and control 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, so as to guide the refrigerant discharged from the exhaust port 51 through the third pipe 8 and the second pipe 7 sequentially into the intake port 52.

[0092] Based on the above architecture, when operating in heating mode, if the outdoor ambient temperature is determined to be lower than the first preset temperature, during the heating start-up phase of the heating mode, the second expansion valve 14 and the third expansion valve 15 are controlled to open, and the first expansion valve 13 is controlled to close; the third solenoid valve 12 and the fifth solenoid valve 17 are controlled to open, 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 51 through the third pipeline 8 and the second pipeline 7 in sequence and then into the air inlet 52. This allows the refrigerant to 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 start normally under low temperature conditions.

[0093] For example, if the outdoor ambient temperature is determined to be lower than the first preset temperature, and the air conditioner 100 is in the heating start-up stage of the heating mode, the controller controls the second expansion valve 14 and the third expansion valve 15 to open and controls the first expansion valve 13 to close; it controls the third solenoid valve 12 and the fifth solenoid valve 17 to open and controls 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 shown in Figure 4. That is to say, the high-temperature refrigerant discharged from the exhaust port 51 of the compressor 5 enters the third heat exchanger 4 after passing through the third solenoid valve 12, where it exchanges heat to heat the heating water. Then, it passes through the third expansion valve 15 and the second expansion valve 14 and enters the second heat exchanger 3 to exchange heat with the domestic water in the water tank 1. Finally, it returns to the intake port 52 of the compressor 5 through the fifth solenoid valve 17, thereby establishing a pressure difference for the refrigeration system, rapidly increasing the oil temperature of the compressor 5, thus achieving low-temperature start-up of the compressor 5 and improving the reliability of the compressor 5.

[0094] In some embodiments, after the valves complete their operation, the compressor runs at an initial frequency for a certain period, such as 3 minutes, and then performs normal loading and unloading operation to ensure stable compressor operation. During this time, the water tank acts as a low-temperature heat source to provide heat. The initial frequency ranges from 25Hz to 45Hz.

[0095] In some embodiments, the heating mode may also include a normal heating operation phase, and the controller may also be configured to execute step S217: when the compressor 5 meets the normal operation conditions, control the air conditioner 100 to enter the normal heating operation phase from the heating start phase.

[0096] For example, when compressor 5 starts, the controller detects compressor 5. If compressor 5 meets the normal operating conditions, that is, if the operating parameters of compressor 5 all meet the normal operating conditions, then compressor 5 is confirmed to have started successfully, and air conditioner 100 can normally enter heating mode. This controls air conditioner 100 to enter normal heating operation mode from the heating start-up stage, and the controller controls air conditioner 100 to perform heating.

[0097] In some embodiments, the normal operating condition is that the exhaust temperature of the compressor 5 is higher than a third preset temperature.

[0098] For example, the oil temperature of compressor 5 must reach a sufficiently high operating temperature for compressor 5 to function properly. Therefore, a temperature sensor can be installed at the discharge port 51 of compressor 5 to monitor the discharge temperature of compressor 5. That is, the oil temperature of compressor 5 is monitored by the discharge temperature, and the obtained discharge temperature is sent to the controller. If the discharge temperature is higher than the third preset temperature, compressor 5 can function normally and air can be used as a heat source; conversely, if the discharge temperature is not higher than the third preset temperature, compressor 5 cannot function normally, and air conditioner 100 should continue to maintain the heating start-up phase and use water tank 1 as a heat source to ensure that compressor 5 can start normally.

[0099] In some embodiments, the controller may also be configured to perform the following steps: step S218, during the heating start-up phase, after the compressor 5 has been running for a preset time, determining that the exhaust temperature of the compressor 5 is lower than a third preset temperature; step S219, controlling the compressor 5 to increase its frequency to the highest operating frequency.

[0100] For example, when compressor 5 starts, to protect it from damage, it will operate at a certain initial frequency, such as 25Hz, 35Hz, or 45Hz, without specific limitations. After compressor 5 operates at the initial frequency for a preset time, it attempts to operate normally. At this time, the controller obtains the discharge temperature of compressor 5. If it is determined that the discharge temperature is lower than the third preset temperature, the oil temperature of compressor 5 is not high enough to start normally. In this case, the controller increases the frequency of compressor 5 to the highest operating frequency to quickly raise the oil temperature of compressor 5 to ensure that compressor 5 can meet the requirements for normal operation, so that air conditioner 100 can quickly provide heating for users. Conversely, if it is determined that the discharge temperature is not lower than the third preset temperature, compressor 5 can operate normally. Then, air conditioner 5 enters the normal heating operation stage from the heating start-up stage, using outdoor air as a heat source, and the controller controls air conditioner 100 to provide heating. The third preset temperature can be set according to actual conditions, such as 50℃, 55℃, or 60℃, without specific limitations.

[0101] In some embodiments, the heating mode may further include a normal heating operation phase. The controller may also be configured to perform the following steps: step S220, receiving a heating mode operation command and determining that the outdoor ambient temperature is higher than a first preset temperature; step S221, controlling the air conditioner to directly enter the normal heating operation phase.

[0102] For example, if the controller receives a command to operate in heating mode and determines that the outdoor ambient temperature is higher than the first preset temperature, then the outdoor air, as a heat source, can ensure that the compressor 5 starts normally. Without using the water tank 1 as a heat source, the air conditioner 100 can directly provide heating without requiring any further configuration from the controller, thus shortening the response time and promptly meeting the user's heating needs.

[0103] In some embodiments, as shown in FIG5, the controller may also be configured to, after entering the normal heating operation stage, control the first expansion valve 13 and the third expansion valve 15 to be turned on, and control the second expansion valve 14 to be turned off; control 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 to be turned off, and control the third solenoid valve 12 and the seventh solenoid valve 19 to be turned on.

[0104] For example, when 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 open and the second expansion valve 14 to close; it controls 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 to close and the third solenoid valve 12 and the seventh solenoid valve 19 to open. At this time, the refrigerant flow direction is as shown in Figure 5. That is to say, the high-temperature refrigerant discharged from the exhaust port 51 of the compressor 5 enters the third heat exchanger 4 after passing through the third solenoid valve 12, where heat exchange takes place to heat the heating water. Then, it passes through the third expansion valve 15 and the first expansion valve 13, and then enters the outdoor air in the first heat exchanger 2 for heat exchange. Finally, it returns to the intake port 52 of the compressor 5 through the seventh solenoid valve 19, completing the heating cycle of the air conditioner 100.

[0105] In some embodiments, the controller may also be configured to perform the following steps: step S222, during the heating start-up phase, acquiring the domestic water temperature; step S223, when it is determined that the domestic water temperature is lower than the second preset temperature, controlling the water tank 1 to start electric heating; step S224, when it is determined that the domestic water temperature is higher than the second preset temperature, controlling the water tank 1 to stop electric heating.

[0106] For example, the temperature of domestic water in water tank 1 can be obtained by a sensor and sent to the controller. When the air conditioner 100 is in the heating start-up stage, in order to ensure that the heat carried by the refrigerant after heat exchange with the domestic water in water tank 1 can meet the low-temperature start-up requirements of the compressor 5, the domestic water temperature should be high enough, that is, the domestic water temperature should be 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 water tank 1. Therefore, the electric heating of water tank 1 is activated to heat the domestic water in water tank 1. And when it is determined that the domestic water temperature is higher than the second preset temperature, the electric heating of water tank 1 is stopped in time to avoid energy waste.

[0107] In some embodiments, as shown in FIG1, the air conditioner 100 may include a first water pump 20.

[0108] The first water pump 20 is located on the connecting pipe between the second heat exchanger 3 and the water tank 1. Based on the design of the first water pump 20, the controller can also be configured to control the first water pump 20 to operate at its maximum speed during the heating start-up phase. And when there is no demand for hot water, the controller will shut down the first water pump 20 after the air conditioner enters the normal heating operation phase.

[0109] For example, during the heating start-up phase, by controlling the first water pump 20 to operate at its maximum speed, the heat exchange efficiency between the domestic water and the refrigerant in the water tank 1 is improved, thereby shortening the start-up time of the compressor 5 and meeting the user's heating needs as soon as possible.

[0110] In some embodiments, the controller may also be configured to perform the following steps: Step S203, Start. Step S204, The air conditioner operates in heating mode. Step S205, Detect the outdoor ambient temperature. Step S206, Check if the outdoor ambient temperature is lower than a first preset temperature; if yes, proceed to step S207; if no, proceed to step S215. Step S207, Detect the domestic water temperature. Step S208, Check if the domestic water temperature is lower than a second preset temperature; if yes, proceed to step S210; if no, proceed to step S209. Step S209, Turn on the electric heating of the water tank, and proceed to step S207. Step S210, The third and fifth solenoid valves are turned on, and the first, second, fourth, sixth, and seventh solenoid valves are turned off. Step S211, Control the second and third expansion valves to turn on, and control the first expansion valve to close. Step S212, The compressor runs for a preset time. Step S213: Is the compressor's exhaust temperature lower than the third preset temperature? If yes, proceed to step S215; if no, proceed to step S214. Step S214: The compressor frequency is increased to the highest operating frequency; proceed to step S212. Step S215: The air conditioner transitions from the heating start-up phase to the normal heating operation phase. Step S216: The electric heating element in the water tank is turned off.

[0111] Based on the above architecture, the air conditioner 100 disclosed herein can also utilize the heat from the water tank to quickly defrost the air conditioner, ensuring that the air conditioner can effectively defrost even at extremely low temperatures, thereby improving the reliability of the air conditioner.

[0112] As shown in Figures 1 and 6, the air conditioner 100 provided according to the embodiments of this disclosure may include: 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, and a control valve 30.

[0113] The water tank 1 is used to store domestic water. The first heat exchanger 2 is located outdoors and can be a finned heat exchanger for exchanging heat with the circulating refrigerant. The second heat exchanger 3 is connected to the water tank 1 and is used for exchanging heat with the domestic water. The second heat exchanger 3 can be a tube heat exchanger, a plate heat exchanger, or other form of refrigerant-water heat exchange device. The third heat exchanger 4 is located indoors and is used to regulate indoor temperature; the third heat exchanger 4 can be a plate heat exchanger. The compressor 5 has an exhaust port 51 and an intake port 52. The beginning ends of the first pipeline 6 and the second pipeline 7 are both connected to the exhaust port 51. The ends of the first pipeline 6 and the second pipeline 7 are both connected to the beginning end of the third pipeline 8. The end of the third pipeline 8 is connected to the exhaust port 51. The first heat exchanger 2 is located on the first pipeline 6. The second heat exchanger 3 is located on the second pipeline 7. The third heat exchanger 4 is located on the third pipeline 8. The control valve 30 is located between the exhaust port 51 and the beginning of the first pipeline 6, the beginning of the second pipeline 7, the end of the third pipeline 8, and the air inlet 52. The control valve 30 is used to change the flow direction of the refrigerant discharged at the exhaust port 51 and can also be used for pipeline flow regulation.

[0114] In some embodiments, the air conditioner 100 may further include a controller connected to the control valve 30. The controller may be configured to perform the following steps S301-S302.

[0115] Step S301: In defrosting mode, determine that the domestic water temperature is higher than the first preset temperature.

[0116] The first preset temperature can be understood as the temperature value at which domestic water can melt frost, based on the experimental preset. The first preset temperature can be 10℃, and there is no specific restriction on it.

[0117] For example, if the domestic water temperature is low, the first heat exchanger 2 uses the heat from the domestic water for defrosting, which cannot quickly and effectively melt the frost, increasing energy consumption and defrosting costs. Therefore, in this embodiment of the present disclosure, during defrosting mode, it is necessary to determine that the domestic water temperature is higher than a first preset temperature before the heat from the domestic water in the water tank 1 can be used for defrosting, thereby ensuring the defrosting effect of the first heat exchanger 2 and improving energy utilization efficiency.

[0118] In step S302, the opening and closing of the control valve 30 are controlled so that the refrigerant discharged from the exhaust port 51 enters the intake port 52 after passing through the first pipe 6 and the second pipe 7 in sequence.

[0119] To address this issue, this embodiment adds a water tank 1 heat source as a defrosting heat source. When the air conditioner 100 is in defrosting mode, it controls the opening and closing of the control valve 30 to guide the refrigerant discharged from the exhaust port 51 through the first pipeline 6 and the second pipeline 7 before entering the air inlet 52. In other words, the refrigerant discharged by the compressor 5 through the exhaust port 51 no longer enters the water tank 1 to heat the water tank 1 first, but instead 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 before returning to the compressor 5. For example, after absorbing heat from the water tank 1, the refrigerant returns to the compressor 5 and is then discharged through the exhaust port 51. The refrigerant discharged from the exhaust port 51, under the control of the open / closed state of the control valve 30, first passes through the first pipe 6 into the first heat exchanger 2, melting the frost on the first heat exchanger 2. Then, after heat exchange, the refrigerant, under the control of the open / closed state of the control valve 30, passes through the second pipe 7 into the second heat exchanger 3, where it exchanges heat with the hot water in the water tank 1. The heat-absorbing gaseous refrigerant flows back to the air inlet 52 of the compressor 5, thus completing the refrigerant cycle for defrosting. Therefore, in this embodiment, by changing the direction of the refrigerant discharged from the compressor 5's exhaust port 51 through the control valve 30, the refrigerant is controlled to first pass through the first heat exchanger 2 and then flow to the water tank 1 during defrosting mode. This utilizes the heat provided by the hot water in the water tank 1 to quickly defrost the first heat exchanger 2, without affecting the user's heating. Simultaneously, it ensures effective defrosting even at extreme low temperatures, improving the reliability of the air conditioner 100.

[0120] According to the air conditioner 100 of this disclosure, three heat exchangers are respectively installed on different pipelines, and a control valve 30 is installed between each pipeline and the exhaust port 51 of the compressor 5 to regulate the refrigerant flow. Therefore, when the air conditioner 100 is running in defrost mode, the refrigerant discharged from the compressor 5 no longer preferentially passes through the water tank 1, but instead first enters the first heat exchanger 2 through the first pipeline 6 for defrosting. Thus, in this embodiment, by changing the flow direction of the refrigerant discharged from the exhaust port 51 of the compressor 5 through the control valve 30, the refrigerant is controlled to first pass through the first heat exchanger 2 and then flow to the water tank 1 during defrost mode. This allows the heat provided by the hot water in the water tank 1 to quickly defrost the first heat exchanger 2, without affecting the heating at the user end. It also ensures effective defrosting even at extremely low temperatures, improving the reliability of the air conditioner 100.

[0121] In some embodiments, the operating mode of the air conditioner 100 is first determined. If the operating mode is not one or a combination of heating and hot water modes, the first heat exchanger 2 will not frost, and the air conditioner 100 does not need to operate the defrosting mode. If the operating mode is one or a combination of heating and hot water modes, the ambient temperature of the air conditioner 100 is then determined. If the ambient temperature is greater than or equal to the preset ambient temperature, where the preset ambient temperature can be 4°C, the air conditioner 100 does not need to operate the defrosting mode; otherwise, if the ambient temperature is less than the preset ambient temperature, the air conditioner 100 needs to determine whether to operate the defrosting mode.

[0122] In some embodiments, as shown in Figures 1 and 6, the air conditioner 100 may further include a first expansion valve 13, a second expansion valve 14, and a third expansion valve 15. The first expansion valve 13, the second expansion valve 14, and the third expansion valve 15 are used to regulate the flow rate in the pipeline. The control valve 30 includes 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.

[0123] The system comprises the following components: a first expansion valve 13 is mounted on the first pipeline 6; a second expansion valve 14 is mounted on the second pipeline 7; a third expansion valve 15 is mounted on the third pipeline 8; a first solenoid valve 10 is located between the exhaust port 51 and the first end of the sixth solenoid valve 18; a second solenoid valve 11 is located between the exhaust port 51 and the beginning of the second pipeline 7; a second solenoid valve 11 is located between the exhaust port 51 and the end of the third pipeline 8; a fourth solenoid valve 16 is connected to the first end of the third solenoid valve 12 and the end of the third pipeline 8; a 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 air inlet 52; and a sixth solenoid valve 18 is connected to the beginning of the first pipeline 6 and the second end of the seventh solenoid valve 19.

[0124] For example, to solve this problem, in the defrosting mode of this embodiment, the air conditioner 100 controls the conduction 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 to guide the refrigerant discharged from the exhaust port 51 through the first pipeline 6 and the second pipeline 7 in sequence before entering the air inlet 52. That is, the refrigerant absorbs heat from the water tank 1 and returns to the compressor 5 before being discharged through the exhaust port 51. The refrigerant discharged from the exhaust port 51, under the action of the control valve 30, first passes through the first pipeline 6 and enters the first heat exchanger 2 to melt the frost on the first heat exchanger 2. Then, the refrigerant after heat exchange enters the second heat exchanger 3 through the second pipeline 7, where it exchanges heat with the hot water in the water tank 1. The gaseous refrigerant after absorbing heat flows back to the air inlet 52 of the compressor 5, thereby completing the refrigerant cycle for defrosting. Therefore, in this embodiment, a scheme of three expansion valves and seven solenoid valves connected in parallel and in series is adopted to change the flow direction of the refrigerant discharged from the exhaust port 51 of the compressor 5. Thus, when the defrost mode is running, the refrigerant is controlled to first pass through the first heat exchanger 2 and then flow to the water tank 1, so as to use the heat provided by the hot water in the water tank 1 to quickly defrost the first heat exchanger 2, ensuring effective defrosting even at extreme low temperatures and improving the reliability of the air conditioner 100.

[0125] In some embodiments, as shown in FIG7, to control the opening of the control valve 30 so that the refrigerant discharged from the exhaust port 51 sequentially passes through the first pipe 6 and the second pipe 7 before entering the air inlet 52, the controller can be configured to perform the following steps: Step S303, controlling the opening of the first expansion valve 13 and the second expansion valve 14. Step S304, controlling the opening of the first solenoid valve 10, the fifth solenoid valve 17 and the sixth solenoid valve 18, and controlling the closing of the second solenoid valve 11, the fourth solenoid valve 16 and the seventh solenoid valve 19, so that the refrigerant discharged from the exhaust port 51 sequentially passes through the first pipe 6 and the second pipe 7 before entering the air inlet 52.

[0126] For example, in defrosting mode, the air conditioner 100 controls the first expansion valve 13 and the second expansion valve 14 to open, controls the first solenoid valve 10, the fifth solenoid valve 17 and the sixth solenoid valve 18 to open, and controls the second solenoid valve 11, the fourth solenoid valve 16 and the seventh solenoid valve 19 to close. This guides the high-temperature gaseous refrigerant discharged from the compressor 5 exhaust port 51 through the first pipe 6 into the first heat exchanger 2, so that the frost on the first heat exchanger 2 melts. Then, the refrigerant after heat exchange flows back to the compressor 5 intake port 52 through the second pipe 7, thereby completing the refrigerant cycle for defrosting. Therefore, in this embodiment, seven solenoid valves and three electronic expansion valves are connected in parallel and in series to change the direction of the refrigerant discharged from the compressor 5 exhaust port 51. This allows the refrigerant to pass through the first heat exchanger 2 and then flow to the water tank 1 during defrosting mode, so that the heat provided by the hot water in the water tank 1 can quickly defrost the first heat exchanger 2 without affecting the heating at the user end. It also ensures effective defrosting even at extreme low temperatures, thus improving the reliability of the air conditioner 100.

[0127] In some embodiments, the defrosting mode includes a first defrosting mode and a second defrosting mode, wherein in the first defrosting mode, the third expansion valve 15 and the third solenoid valve 12 are controlled to be closed, and in the second defrosting mode, the third expansion valve 15 and the third solenoid valve 12 are controlled to be opened.

[0128] For example, when the air conditioner 100 is running in the first defrosting mode, that is, the air conditioner 100 stops running in the heating mode and then runs in the defrosting mode, the air conditioner 100 stops for defrosting. In other words, as shown in Figure 7, the high-temperature gaseous refrigerant discharged by the compressor 5 flows into the first heat exchanger 2 through the first pipe 6 under the action of the first solenoid valve 10 and the sixth solenoid valve 18 being open and the second solenoid valve 11 and the third solenoid valve 12 being closed. The high-temperature gaseous refrigerant exchanges heat with the first heat exchanger 2, so that the frost on the first heat exchanger 2 melts. The refrigerant after heat exchange is then discharged through the first expansion valve 1. Under the action of the opening of the second expansion valve 14 and the closing of the third expansion valve 15, the refrigerant enters the second pipeline 7 and, after being throttled by the first expansion valve 13 and the second expansion valve 14 into a low-temperature, low-pressure vapor-liquid two-phase refrigerant, enters the second heat exchanger 3. In the second heat exchanger 3, it exchanges heat with the hot water in the water tank 1 to further reduce the refrigerant temperature. After heat exchange, the refrigerant, under the action of the closing of the second solenoid valve 11, the fourth solenoid valve 16, and the seventh solenoid valve 19, and the opening of the fifth solenoid valve 17, enters the air inlet 52 of the compressor 5 through the fifth solenoid valve 17, completing the refrigerant cycle for defrosting. Thus, in this embodiment of the present disclosure, the opening and closing status of each solenoid valve and each expansion valve is controlled by the first defrosting mode, thereby controlling the refrigerant discharged from the exhaust port 51 to sequentially enter the first pipeline 6 and the second pipeline 7, so that the air conditioner 100 can achieve defrosting by stopping.

[0129] Alternatively, when the air conditioner 100 is operating in the second defrosting mode, that is, when the air conditioner 100 is simultaneously operating in heating mode and defrosting mode, the air conditioner 100 achieves defrosting without stopping. In other words, as shown in Figure 8, a portion of the high-temperature gaseous refrigerant discharged from the compressor 5 flows into the first heat exchanger 2 through the first pipe 6 under the action of the first solenoid valve 10 and the sixth solenoid valve 18 being open and the second solenoid valve 11 being closed. The high-temperature gaseous refrigerant then exchanges heat with the first heat exchanger 2, causing the frost on the first heat exchanger 2 to melt. The refrigerant after heat exchange then expands... Under the action of valve 13 and the second expansion valve 14 being open and the third expansion valve 15 being open, the refrigerant enters the second pipeline 7 and, after being throttled by the first expansion valve 13 and the second expansion valve 14 into a low-temperature, low-pressure vapor-liquid two-phase refrigerant, enters the second heat exchanger 3. In the second heat exchanger 3, the refrigerant exchanges heat with the hot water in the water tank 1 to further reduce the temperature of the refrigerant. After the heat exchange, the refrigerant, under the action of the second solenoid valve 11, the fourth solenoid valve 16 and the seventh solenoid valve 19 being closed and the fifth solenoid valve 17 being open, enters the air inlet 52 of the compressor 5 through the fifth solenoid valve 17. Meanwhile, another portion of the high-temperature gaseous refrigerant, under the action of the third solenoid valve 12, enters the third heat exchanger 4 and exchanges heat with the water on the other side of the third heat exchanger 4, thereby heating the heating circulating water. After heat exchange, the refrigerant, under the action of the third expansion valve 15, passes through the third expansion valve 15 and the second expansion valve 14 to become a low-temperature, low-pressure vapor-liquid two-phase refrigerant before entering the second heat exchanger 3. In the second heat exchanger 3, it exchanges heat with the hot water in the water tank 1 to further reduce the refrigerant temperature. The refrigerant after heat exchange is then passed through the second solenoid valve 11, the fourth solenoid valve 16, and the seventh solenoid valve. With the solenoid valve 19 closed and the fifth solenoid valve 17 open, the refrigerant enters the compressor 5's intake port 52 through the fifth solenoid valve 17, completing the defrosting refrigerant circulation. Thus, in this embodiment, the conduction status of each solenoid valve and each expansion valve is controlled by the second defrosting mode, thereby controlling the refrigerant discharged from the exhaust port 51 to sequentially enter the first pipeline 6 and the second pipeline 7, and simultaneously controlling the refrigerant discharged from the exhaust port 51 to sequentially enter the third pipeline 8 and the second pipeline 7, so that the air conditioner 100 can defrost while heating, achieving the function of defrosting without stopping the machine.

[0130] In some embodiments, as shown in Table 6 below, when the air conditioner 100 is running in heating mode or simultaneously in heating mode and defrost mode, it controls the opening or closing of 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.

[0131] Table 6

[0132] In some embodiments, the controller may also be configured to perform the following steps: Step S305, in defrost mode, control the compressor 5 to reduce its frequency to a first target operating frequency. Step S306, after the compressor 5 has been running for a first preset duration, control the first solenoid valve 10, the fifth solenoid valve 17, and the sixth solenoid valve 18 to be turned on, control the first expansion valve 13 to be fully open, control the opening degree of the second expansion valve 14 to the target defrost opening degree, and control the outdoor fan to stop. Step S307, after the compressor 5 has run for a first preset duration again, control the compressor 5 to increase its frequency to the target defrost frequency.

[0133] For example, after the air conditioner 100 enters defrost mode, the compressor 5 reduces its operating frequency from the current frequency to a first target operating frequency, which can be 30Hz. After the compressor 5 maintains operation for a first preset time (which can be 15 seconds), the first solenoid valve 10, the fifth solenoid valve 17, and the sixth solenoid valve 18 are activated, 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 are closed, the first expansion valve 13 is opened to its maximum, the opening of the second expansion valve 14 is controlled to the target defrost opening, and the outdoor fan is stopped. The compressor 5 then runs again for the first preset time, and the compressor 5 is controlled to increase its frequency to the target defrost frequency, which is between 40 and 60Hz. Therefore, by adaptively adjusting the compressor frequency according to the above conditions, stable operation of the compressor can be ensured during defrost.

[0134] When the coil temperature of the first heat exchanger 2 is detected to be ≥15℃, the compressor 5 drops from the target defrosting frequency to 30Hz. After the compressor 5 starts 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 close, the third solenoid valve 12 and the seventh solenoid valve 19 open, the third expansion valve 15 opens to its maximum, the first expansion valve 13 opens to the initial step number at the ambient temperature, and the second expansion valve 14 closes. After the compressor 5 runs for another 15 seconds, the compressor 5 rises to the target defrosting frequency, and after the target defrosting frequency is maintained for 3 minutes, it continues to run according to normal frequency increase and decrease control, and the outdoor fan speed is adjusted to the speed before defrosting.

[0135] In addition, after the air conditioner 100 meets the defrosting conditions, the first expansion valve 13 opens from the current step number to 500 steps, the third expansion valve 15 closes to 0 steps, and the second expansion valve 14 opens from the current step number to the defrosting step number 350. After defrosting is completed, the first expansion valve 13 opens to the initial step number, the third expansion valve 15 opens to the maximum, and the second expansion valve 14 closes from the current step number to 0 steps.

[0136] In some embodiments, in the first defrosting mode, the controller can also be configured to: control the air conditioner 100 to exit the first defrosting mode when the first defrosting exit condition is met, wherein the first defrosting exit condition is that the coil temperature of the first heat exchanger 2 is higher than a preset temperature threshold or the defrosting operation time reaches a second preset duration.

[0137] The preset temperature threshold can be understood as the coil temperature value used to determine whether the frost layer on the first heat exchanger 2 has been melted, based on the experimental preset. The preset temperature threshold can be t2 + outdoor ambient temperature, where t2 ≤ -4 to -10. The second preset duration is the defrosting mode running time used to determine whether the frost layer on the first heat exchanger 2 has been melted. The second preset duration can be any value within the range of [30, 150].

[0138] For example, when the air conditioner 100 is operating in the first defrosting mode (i.e., the air conditioner 100 stops operating in heating mode and then operates in defrosting mode), if the first defrosting exit condition is detected, the air conditioner 100 is controlled to exit the first defrosting mode. That is, if the coil temperature of the first heat exchanger 2 is detected to be higher than a preset temperature threshold, it indicates that the frost layer on the first heat exchanger 2 has been melted, and the air conditioner 100 is controlled to exit the first defrosting mode. Alternatively, if the defrosting operation time reaches a second preset duration (i.e., the air conditioner 100 operates in the first defrosting mode for a period of time equal to the second preset duration), it indicates that the first defrosting mode operation time is sufficient to remove the frost layer on the first heat exchanger 2, and the air conditioner 100 is controlled to exit the first defrosting mode. Therefore, in this embodiment of the disclosure, the ability of the air conditioner 100 to exit the first defrosting mode is determined by the coil temperature and the defrosting operation time, thereby ensuring effective frost melting while avoiding unnecessary energy consumption.

[0139] In addition, if the coil temperature of the first heat exchanger 2 is lower than the preset temperature threshold, or the defrosting operation time has not reached the second preset duration, the air conditioner 100 is controlled to continue to execute the first defrosting mode.

[0140] In some embodiments, in the second defrosting mode, the controller can also be configured to: after determining that the defrosting operation time has reached a fourth preset duration and the coil temperature of the first heat exchanger 2 is lower than a preset temperature threshold, control the operating frequency of the compressor 5 to a second target operating frequency, wherein the second target operating frequency is greater than the target defrosting frequency. The preset temperature threshold can be any value within the range of 10℃ to 20℃.

[0141] The fourth preset duration can be understood as the time that the air conditioner cannot defrost due to insufficient heating capacity, which is preset based on experience. The fourth preset duration can be any value in the range of 5 min to 10 min, and the fourth preset duration can be 5 min, 8 min or 10 min.

[0142] For example, in the second defrosting mode, where the air conditioner 100 operates in both heating and defrosting modes simultaneously, if the defrosting time reaches the fourth preset duration and the coil temperature of the first heat exchanger 2 is below the preset temperature threshold, meaning the frost layer on the first heat exchanger 2 has not completely melted after operating in the second defrosting mode for a period of time, it indicates that the heating capacity of the air conditioner 100 is insufficient. In this case, the operating frequency of the compressor 5 is controlled to the second target operating frequency, which can be the highest frequency. At this time, the compressor 5 frequency needs to be increased to the highest frequency to meet the requirements of simultaneous defrosting and heating. In other words, by increasing the operating frequency of the compressor 5, the refrigerant flow 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, thus completing the defrosting process of the first heat exchanger 2. Therefore, during the second defrosting mode of the air conditioner 100, the heating capacity of the air conditioner 100 is determined by the defrosting operation time. 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. This avoids the problem that the first heat exchanger 2 cannot defrost quickly due to insufficient heating capacity of the air conditioner 100, and improves the defrosting speed.

[0143] In some embodiments, the controller may also be configured to: control the air conditioner 100 to exit the second defrost mode when the second defrost exit condition is met, wherein the second defrost exit condition is that the coil temperature of the first heat exchanger 2 is higher than a preset temperature threshold.

[0144] For example, when the compressor frequency increases from 30Hz to the target defrosting frequency of 60Hz, the air conditioner 100 simultaneously operates in heating mode and defrosting mode (i.e., the second defrosting mode). If the conditions for exiting the second defrosting mode are met, the air conditioner 100 is controlled to exit the second defrosting mode. That is, if the coil temperature of the first heat exchanger 2 is detected to be higher than a preset temperature threshold, it indicates that the frost layer on the first heat exchanger 2 has been melted, and the air conditioner 100 is controlled to exit the second defrosting mode, and the air conditioner 100 continues to operate in heating mode. Therefore, in this embodiment of the present disclosure, the ability of the air conditioner 100 to exit the second defrosting mode is determined by the coil temperature, thereby ensuring effective frost melting while avoiding unnecessary energy consumption.

[0145] In some embodiments, in the second defrosting mode, after controlling the operating frequency of the compressor 5 to the second target operating frequency, the second defrosting mode is exited and the next heating operation is restarted until the coil temperature of the first heat exchanger 2 is higher than the preset temperature threshold.

[0146] In some embodiments, the controller may also be configured to: control the air conditioner 100 to enter defrost mode 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 time of the air conditioner 100 reaches a first preset time. The frosting temperature range can be -4 to -10.

[0147] The first preset duration can be understood as the operating time of the air conditioner 100 used to determine whether the first heat exchanger 2 is frosted, as set in the experiment. The first preset duration can be any value within the range of 20 min to 150 min. The first preset duration can be 20 min, 50 min, 90 min, 100 min, 140 min or 150 min, and there is no specific restriction on it.

[0148] For example, since the first heat exchanger 2 is located outdoors, when the air conditioner 100 is running in heating mode, the first heat exchanger 2 absorbs heat from the outdoor environment, causing the outdoor ambient temperature to drop sharply. If the air conditioner 100 runs for a long time, the first heat exchanger 2 will frost. Based on this, in this embodiment of the disclosure, 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 a first preset time is set to determine whether the first heat exchanger 2 will frost. That is, 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 means that the coil temperature of the first heat exchanger 2 and the outdoor ambient temperature are very low, which can easily cause the first heat exchanger 2 to frost. And when it is determined that the running time of the air conditioner 100 has reached the first preset time, it means that the air conditioner 100 running in heating mode for a long time will cause the first heat exchanger 2 to frost. Then the air conditioner 100 is controlled to enter the defrosting mode to defrost the first heat exchanger 2. Therefore, in this embodiment of the present disclosure, the temperature difference between the coil temperature of the first heat exchanger 2 and the outdoor ambient temperature and the running time of the air conditioner 100 are used to determine whether the first heat exchanger 2 is frosted. After it is determined that the first heat exchanger 2 is frosted, the air conditioner 100 is controlled to run the defrosting mode so that the air conditioner 100 can defrost the first heat exchanger 2 in a timely manner.

[0149] For example, the frosting temperature range is -10℃ to -4℃, the first preset duration is 20 minutes, after the air conditioner 100 is turned on, it runs in heating mode. After the air conditioner 100 runs for a period of time, it checks whether the air conditioner 100 meets the defrosting requirements. That is, if the temperature difference between the coil temperature of the first heat exchanger 2 and the outdoor ambient temperature is detected to be between -10℃ and -4℃, and the running time of the air conditioner 100 reaches 20 minutes, that is, the air conditioner 100 runs in heating mode for 20 minutes, then the air conditioner 100 is controlled to enter defrosting mode. If it does not meet the requirements, it continues to run in heating mode.

[0150] In some embodiments, the air conditioner 100 further includes a water pump (first water pump 20), which is located on the connecting pipe between the second heat exchanger 3 and the water tank 1. The controller can also be configured to control the water pump to operate at its maximum speed in defrost mode. That is, when the air conditioner 100 is in defrost mode, the water pump is controlled to operate at its maximum speed to provide maximum power for the water flow between the second heat exchanger 3 and the water tank 1, thereby accelerating the absorption of heat from domestic hot water.

[0151] In addition, the water pump is turned off after the air conditioner 100 exits defrost mode.

[0152] The control process of the first defrosting mode in some embodiments of this disclosure is described below, with specific details as follows: Step S308, Start. Step S309, Determine whether the air conditioner's operating mode is heating mode; if yes, proceed to step S312; otherwise, proceed to step S310. Step S310, Determine whether the air conditioner's operating mode is hot water mode; if yes, proceed to step S312; otherwise, proceed to step S311. Step S311, If ​​the air conditioner is not frosted, the first defrosting mode does not need to be executed. Step S312, Determine whether the ambient temperature of the air conditioner's operating environment is less than 4°C; if yes, proceed to steps S313 and S314; otherwise, proceed to step S311. Step S313, Determine whether the coil temperature of the first heat exchanger is lower than a preset temperature threshold; if yes, proceed to step S315; otherwise, re-determine step S313. Step S314, Determine whether the air conditioner's operating time has reached a first preset time; if yes, proceed to step S315; otherwise, re-determine step S314. Step S315, The air conditioner needs defrosting. Step S316: Determine if the domestic water temperature is higher than the first preset temperature. If yes, proceed to step S318; otherwise, proceed to step S317. Step S317: The air conditioner is not allowed to use the water tank's heat for defrosting. Step S318: The air conditioner is allowed to use the water tank's heat for defrosting. Step S319: Determine if the coil temperature of the first heat exchanger is higher than the preset temperature threshold. If yes, proceed to step S321; otherwise, proceed to step S320. Step S320: Determine if the defrosting operation time has reached the second preset duration. If yes, proceed to step S21; otherwise, proceed to step S18. Step S321: The air conditioner exits the first defrosting mode. Step S322: End.

[0153] The control process of the second defrosting mode according to an embodiment of the present invention is described below, with specific details as follows: Step S323, Start. Step S324, The air conditioner operates in heating mode. Step S325, Input the coil temperature of the first heat exchanger. Step S326, Input the running time of the air conditioner. Step S327, Determine whether the coil temperature of the first heat exchanger and the running time of the air conditioner meet the defrosting 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 running time of the air conditioner has reached the first preset time. If yes, proceed to step S328; otherwise, proceed to step S324. Step S328, The compressor frequency is reduced to the first target operating frequency. Step S329, Control the conduction status of the solenoid valve. Step S330, Control the conduction status of the expansion valve. Step S331, Control the outdoor fan to stop. Step S332, Control the compressor frequency to increase to the target defrosting frequency. Step S333: Determine if the coil temperature of the first heat exchanger is higher than the preset temperature threshold. If yes, proceed to step S336; otherwise, proceed to step S334. Step S334: Determine if the defrosting operation time has reached the fourth preset duration. If yes, proceed to step S335; otherwise, proceed to step S333. Step S335: Control the compressor to increase its frequency to the second target operating frequency. Step S336: Control the air conditioner to exit the second defrosting mode. Step S337: End.

[0154] Those skilled in the art will understand that the scope of this disclosure is not limited to the specific embodiments described above, and that modifications and substitutions can be made to certain elements of the embodiments without departing from the spirit of this disclosure. The scope of this disclosure is limited by the appended claims.

Claims

1. An air conditioner, comprising: Water tank, the water tank being used to store domestic water; The first heat exchanger, located outdoors, is used to exchange heat with the circulating refrigerant; The second heat exchanger is connected to the water tank and is used to exchange heat with the domestic water. The third heat exchanger, located indoors, is used to regulate the indoor temperature; The compressor has an exhaust port and an intake port; The system comprises a first pipeline, a second pipeline, and a third pipeline, wherein the first end of the first pipeline is connected to the exhaust port via a first solenoid valve, the first end of the second pipeline is connected to the exhaust port via a second solenoid valve, the ends of the first pipeline and the second pipeline are both used to connect to the first end of the third pipeline, and the end of the third pipeline is connected to the exhaust port via 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 are provided, wherein the first expansion valve is provided on the first pipeline, the second expansion valve is provided on the second pipeline, and the third expansion valve is provided on the third pipeline; The fourth, fifth, sixth, and seventh solenoid valves are provided. 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. The second end of the sixth solenoid valve is connected to the beginning of the first pipeline and the second end of the seventh solenoid valve. A controller configured to control the conduction of each solenoid valve and each expansion valve according to the operating mode of the air conditioner.

2. The air conditioner according to claim 1, wherein the controller is configured to control the conduction of each solenoid valve and each expansion valve according to the operating mode of the air conditioner, the controller being configured to: When the operating mode is the simultaneous cooling and hot water production total heat recovery mode, the second solenoid valve and the fourth solenoid valve are both opened, the first solenoid valve, the third solenoid valve, the fifth solenoid valve, the sixth solenoid valve and the seventh solenoid valve are all closed, and the first expansion valve is closed, the second expansion valve is open and the third expansion valve is open.

3. The air conditioner according to claim 1 or 2, wherein the controller is configured to control the conduction of each solenoid valve and each expansion valve according to the operating mode of the air conditioner, the controller being configured to: When the operating mode is a simultaneous cooling and hot water production partial heat recovery mode, the first solenoid valve, the second solenoid valve, the fourth solenoid valve and the sixth solenoid valve are all opened, the third solenoid valve, the fifth solenoid valve and the seventh solenoid valve are all closed, and the first expansion valve, the second expansion valve and the third expansion valve are all turned on.

4. The air conditioner according to any one of claims 1-3, wherein the controller is further 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 compressor's shutdown time reaches the preset time, the compressor is controlled to start so that the air conditioner operates in 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 compressor's off-time reaches the preset duration, the compressor is controlled to start, so that the air conditioner operates in hot water production mode. The hot water production modes include a total heat recovery mode and a 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 compressor's shutdown time reaches the preset time, the compressor is controlled to start, so that the air conditioner operates in a simultaneous cooling and hot water production mode.

5. The air conditioner according to any one of claims 1-4, wherein 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 compressor's operating frequency is controlled based on the first temperature difference and the second temperature difference.

6. The air conditioner according to claim 3, wherein when controlling the first expansion valve in the hot water production section heat recovery mode, the controller is further configured to: Determine the third temperature difference between the coil temperature of the first heat exchanger and the outdoor ambient temperature; The first opening increment of the first expansion valve is determined based on the third temperature difference; Adjust the opening degree of the first expansion valve according to the first opening degree increment.

7. The air conditioner according to claim 4, wherein when controlling the second expansion valve in hot water production mode, the controller is further configured to: The condensation temperature of the refrigerant is obtained, and a fourth temperature difference between the condensation temperature and the domestic water temperature is determined. The second opening increment of the second expansion valve is determined based on the domestic water temperature and the fourth temperature difference; Adjust the opening degree of the second expansion valve according to the second opening degree increment.

8. The air conditioner according to claim 4, when controlling the third expansion valve in simultaneous cooling and hot water production mode, the controller is further configured to: The liquid pipe temperature of the third heat exchanger, the exhaust temperature of the compressor, and the inlet water temperature of the third heat exchanger are obtained. Determine the fifth temperature difference between the inlet water temperature and the liquid pipe temperature; The third opening increment of the third expansion valve is determined based on the exhaust 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 1-3, further comprising an outdoor fan, and the controller further configured to: In the hot water total heat recovery mode, the outdoor fan is turned off; In the heat recovery mode of the hot water production section, a sixth temperature difference is determined between the condensation temperature of the refrigerant and the coil temperature of the first heat exchanger, and the speed of the outdoor fan is controlled according to the sixth temperature difference.

10. The air conditioner according to claim 9, wherein the controller is specifically configured to control the speed of the outdoor fan based on the sixth temperature difference as follows: If the sixth temperature difference is higher than the first temperature difference threshold, then the speed of the outdoor fan is reduced. If the sixth temperature difference is lower than the second temperature difference threshold, the speed of the outdoor fan is increased, and the first temperature difference threshold is greater than the second temperature difference threshold.

11. An air conditioner, comprising: Water tank, the water tank being used to store domestic water; The first heat exchanger, located outdoors, is used to exchange heat with the circulating refrigerant; The second heat exchanger is connected to the water tank and is used to exchange heat with the domestic water. The third heat exchanger, located indoors, is used to regulate the indoor temperature; The compressor has an exhaust port and an intake port; A first pipeline, a second pipeline, and a third pipeline, wherein the beginning ends of the first pipeline and the second pipeline are both used to connect to the exhaust port, the ends of the first pipeline and the second pipeline are both used to connect to the beginning end of the third pipeline, and the end of the third pipeline is used to connect to the exhaust port. 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 control valve is disposed between the exhaust port and the beginning of the first pipeline, the beginning of the second pipeline, the end of the third pipeline, and the air inlet. The control valve is used to change the flow direction of the refrigerant discharged at the exhaust port. A controller, connected to the control valve, is configured to: Activate heating mode and confirm that the outdoor ambient temperature is lower than the first preset temperature; During the heating start-up phase of the heating mode, the opening and closing of the control valve are controlled to guide the refrigerant discharged from the exhaust port through the third pipeline and the second pipeline in sequence before entering the air inlet.

12. The air conditioner according to claim 11, The air conditioner further includes 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; The control valve includes a first solenoid valve, a second solenoid valve, a third solenoid valve, a fourth solenoid valve, a fifth solenoid valve, a sixth solenoid valve, and a seventh solenoid valve. The first solenoid valve is disposed between the exhaust port and the first end of the sixth solenoid valve. The second solenoid valve is disposed between the exhaust port and the beginning end of the second pipeline. The second solenoid valve is disposed between the exhaust port and the end of the third pipeline. 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 second end of the sixth solenoid valve is connected to the beginning end of the first pipeline and the second end of the seventh solenoid valve.

13. The air conditioner according to claim 12, wherein the controller is specifically configured to control the opening and closing of the control valve to guide the refrigerant discharged from the exhaust port through the third pipeline and the second pipeline in sequence before entering the air inlet. Control the second and third expansion valves to open, and control the first expansion valve to close; The third and fifth solenoid valves are turned on, while the first, second, fourth, sixth, and seventh solenoid valves are turned off, so as to guide the refrigerant discharged from the exhaust port through the third pipeline and the second pipeline in sequence before entering the intake port.

14. The air conditioner according to claim 12, wherein the heating mode further includes a normal heating operation phase, and the controller is further configured to: When the compressor meets the normal operating conditions, the air conditioner is controlled to enter the normal operating heating phase from the heating start-up phase.

15. The air conditioner according to claim 14, wherein the normal operating condition is that the exhaust temperature of the compressor is higher than a third preset temperature.

16. The air conditioner of claim 14, wherein The controller is also configured to: During the heating start-up phase, after the compressor has been running for a preset period of time, it is determined that the exhaust temperature of the compressor is lower than a third preset temperature. Control the compressor to increase its frequency to the highest operating frequency.

17. The air conditioner according to claim 12, wherein the heating mode further includes a normal heating operation phase, and the controller is further configured to: Upon receiving the instruction to operate the heating mode, it is determined that the outdoor ambient temperature is higher than the first preset temperature; The air conditioner is controlled to directly enter the normal heating operation phase.

18. The air conditioner according to claim 14 or 17, wherein the controller is further configured to: After entering the normal heating operation phase, the first expansion valve and the third expansion valve are turned on, and the second expansion valve is turned off. The first, second, fourth, fifth, and sixth solenoid valves are all closed, while the third and seventh solenoid valves are all open.

19. The air conditioner according to any one of claims 11-18, wherein the controller is further configured to: During the heating start-up phase, the temperature of the domestic hot water is obtained; When the temperature of the domestic water is determined to be lower than the second preset temperature, the water tank is controlled to start electric heating. When the temperature of the domestic water is determined to be higher than the second preset temperature, the water tank is controlled to stop electric heating.

20. The air conditioner according to any one of claims 11-19, further comprising a water pump disposed on a connecting pipe between the second heat exchanger and the water tank, and the controller further configured to: During the heating start-up phase, the water pump is controlled to operate at its maximum speed.

21. An air conditioner, comprising: Water tank, the water tank being used to store domestic water; The first heat exchanger, located outdoors, is used to exchange heat with the circulating refrigerant; The second heat exchanger is connected to the water tank and is used to exchange heat with the domestic water. The third heat exchanger, located indoors, is used to regulate the indoor temperature; The compressor has an exhaust port and an intake port; A first pipeline, a second pipeline, and a third pipeline, wherein the beginning ends of the first pipeline and the second pipeline are both used to connect to the exhaust port, the ends of the first pipeline and the second pipeline are both used to connect to the beginning end of the third pipeline, and the end of the third pipeline is used to connect to the exhaust port. 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 control valve is disposed between the exhaust port and the beginning of the first pipeline, the beginning of the second pipeline, the end of the third pipeline, and the air inlet. The control valve is used to change the flow direction of the refrigerant discharged at the exhaust port. A controller, connected to the control valve, is configured to: In defrost mode, the domestic water temperature is set higher than the first preset temperature; The control valve is controlled to guide the refrigerant discharged from the exhaust port through the first pipeline and the second pipeline in sequence before entering the intake port.

22. The air conditioner according to claim 21, The air conditioner further includes 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; The control valve includes a first solenoid valve, a second solenoid valve, a third solenoid valve, a fourth solenoid valve, a fifth solenoid valve, a sixth solenoid valve, and a seventh solenoid valve. The first solenoid valve is disposed between the exhaust port and the first end of the sixth solenoid valve. The second solenoid valve is disposed between the exhaust port and the beginning end of the second pipeline. The second solenoid valve is disposed between the exhaust port and the end of the third pipeline. 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 second end of the sixth solenoid valve is connected to the beginning end of the first pipeline and the second end of the seventh solenoid valve.

23. The air conditioner according to claim 22, wherein the controller is specifically configured to control the opening and closing of the control valve to guide the refrigerant discharged from the exhaust port through the first pipeline and the second pipeline sequentially into the air inlet. Control the first expansion valve and the second expansion valve to be turned on; The first, fifth, and sixth solenoid valves are controlled to be turned on, while the second, fourth, and seventh solenoid valves are controlled to be turned off, so as to guide the refrigerant discharged from the exhaust port through the first pipeline and the second pipeline in sequence before entering the air inlet.

24. The air conditioner of claim 23, the defrost mode comprising a first defrost mode and a second defrost mode, wherein, In the first defrosting mode, the third expansion valve and the third solenoid valve are controlled to close; in the second defrosting mode, the third expansion valve and the third solenoid valve are controlled to open.

25. The air conditioner according to claim 23 or 24, wherein the controller is further configured to: In the defrosting mode, the compressor is controlled to reduce its frequency to the first target operating frequency; After the compressor has been running for a first preset time, the first solenoid valve, the fifth solenoid valve and the sixth solenoid valve are turned on, the first expansion valve is fully opened, the opening degree of the second expansion valve is set to the target defrosting degree, and the outdoor fan is stopped. After the compressor runs for a first preset time again, the compressor frequency is controlled to increase to the target defrosting frequency.

26. The air conditioner according to claim 24, wherein in the first defrosting mode, the controller is further configured to: satisfying a first defrosting exit condition, controlling the air conditioner to exit the first defrosting mode, wherein The first defrosting exit condition is that the coil temperature of the first heat exchanger is higher than the preset temperature threshold or the defrosting operation time reaches the second preset duration.

27. The air conditioner according to claim 24, wherein in the second defrosting mode, the controller is further configured to: Once the defrosting operation time reaches the fourth preset duration and the coil temperature of the first heat exchanger is lower than the preset temperature threshold, the operating frequency of the compressor is controlled to be the second target operating frequency, which is greater than the target defrosting frequency.

28. The air conditioner according to claim 27, wherein the controller is further configured to: satisfying a second defrosting exit condition, controlling the air conditioner to exit the second defrosting mode, wherein The second defrosting exit condition is that the coil temperature of the first heat exchanger is higher than a preset temperature threshold.

29. The air conditioner according to any one of claims 21-28, wherein the controller is further configured to: When the temperature difference between the coil temperature of the first heat exchanger and the outdoor ambient temperature is within the frosting temperature range, and the operating time of the air conditioner reaches the first preset time, the air conditioner is controlled to enter the defrosting mode.

30. The air conditioner according to any one of claims 21-29, further comprising a water pump disposed on a connecting pipe between the second heat exchanger and the water tank, and the controller further configured to: In the defrosting mode, the water pump is controlled to operate at its maximum speed.

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