Air conditioning system and control method thereof

Abstract

The invention provides an air conditioning system and a control method thereof.The air conditioning system comprises a refrigerant circulation loop and a liquid storage tank, the refrigerant circulation loop is formed by connecting a compressor, a four-way valve, an outdoor heat exchanger, an indoor heat exchanger and a gas-liquid separator through pipelines, and the four-way valve is provided with a first port, a second port, a third port and a fourth port; the first port is connected to an exhaust port of the compressor, the second port is connected to the outdoor heat exchanger, the third port is connected to the indoor heat exchanger, the fourth port is connected to an inlet of the gas-liquid separator, and the liquid storage tank is connected between the third port and the indoor heat exchanger through the first control valve and the second control valve. The liquid storage tank is further connected to an inlet of the gas-liquid separator through a third control valve. According to the invention, the refrigerant adjusting and transferring functions are realized only by additionally arranging a single liquid storage tank and simply connecting a proper number of control valves with parts and pipelines of the air conditioning system, so that the pipeline structure is obviously simplified, the cost is reduced, and the space utilization rate of a product is improved.

Description

Technical Field

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

[0002] After the air-conditioning system runs in defrost mode, there is a problem of system refrigerant accumulating on the outdoor low-pressure side. By optimizing the connection between the vapor-liquid separator and other components in the air-conditioning system, it can be achieved that after the defrost is completed and switched to the heating mode, the gaseous refrigerant is discharged through the exhaust pipe of the vapor-liquid separator to form a flow pressure difference, which provides power for the vapor-liquid separator to discharge the liquid refrigerant through the drain pipe, shortens the time for the vapor-liquid separator to discharge the liquid refrigerant, reduces the time for the heating capacity to recover to the maximum output after defrosting, and improves the heating capacity. This function can be referred to as the refrigerant transfer function.

[0003] During the operation of the air-conditioning system, there is a problem of inconsistent refrigerant demand in different operating modes. By adding a liquid storage tank to the air-conditioning system to store and release the refrigerant, the amount of refrigerant in different operating modes can be controlled, so that the amount of refrigerant circulating in the system is consistent with the refrigerant demand in different operating modes, thereby achieving the best heat exchange effect. This function can be referred to as the refrigerant adjustment function.

[0004] However, the prior art does not have a method of simply adding a tank and an appropriate number of control valves to the air-conditioning system to simply connect the components and pipes in the air-conditioning system to simultaneously achieve the refrigerant transfer and refrigerant adjustment functions, which makes this technical gap an important direction for optimizing the air-conditioning system. Summary of the invention

[0005] Therefore, the present invention provides an air-conditioning system that can solve the technical problem that the existing air-conditioning system cannot simply connect with the components and pipelines in the air-conditioning system by adding a tank and an appropriate number of control valves to simultaneously realize the refrigerant transfer and refrigerant adjustment functions.

[0006] In order to solve the above problems, the present invention provides an air-conditioning system, including: a compressor, a four-way valve, an outdoor heat exchanger, an indoor heat exchanger, a gas-liquid separator and a liquid storage tank, the compressor, the four-way valve, the outdoor heat exchanger, the indoor heat exchanger, and the gas-liquid separator are connected by pipelines to form a refrigerant circulation loop, the four-way valve has a first port, a second port, a third port and a fourth port, the first port is connected to the exhaust port of the compressor, the second port is connected to the outdoor heat exchanger, the third port is connected to the indoor heat exchanger, the fourth port is connected to the inlet of the gas-liquid separator, the liquid storage tank is connected between the third port and the indoor heat exchanger through a first control valve, the liquid storage tank is also connected between the third port and the indoor heat exchanger through a second control valve, and the liquid storage tank is also connected to the inlet of the gas-liquid separator through a third control valve.

[0007] In some embodiments, the liquid storage tank is further connected between the outdoor heat exchanger and the indoor heat exchanger through a fourth control valve.

[0008] In some embodiments, the liquid storage tank is further connected between the third port and the indoor heat exchanger via a fifth control valve, and a first valve port of the fifth control valve is connected to a position close to the bottom of the liquid storage tank.

[0009] In some embodiments, the first valve port of the first control valve is connected to the top of the liquid storage tank; and / or the first valve port of the second control valve is connected to the top of the liquid storage tank.

[0010] In some embodiments, the first valve port of the third control valve is connected to a position close to the bottom of the liquid storage tank.

[0011] In some embodiments, a sixth control valve is further included, wherein a first valve port of the sixth control valve is connected between the liquid storage tank and the first control valve, and a second valve port of the sixth control valve is connected between the third control valve and an inlet of a gas-liquid separator.

[0012] In some embodiments, the second valve port of the first control valve is connected to the first node of the refrigerant circulation loop, the second valve port of the second control valve is connected to the second node of the refrigerant circulation loop, a seventh control valve is provided in the refrigerant circulation loop, and the seventh control valve is located between the first node and the second node.

[0013] In some embodiments, an oil separator is further provided in the refrigerant circulation loop, and the oil separator is located between the exhaust port of the compressor and the first port.

[0014] The present invention also provides a control method for an air conditioning system, which is used to control the operation of the aforementioned air conditioning system, and the control method comprises:

[0015] Obtaining an operating mode of the air conditioning system;

[0016] According to the operation mode, the opening and closing of the first control valve, the second control valve, the third control valve, the fourth control valve, the fifth control valve, the sixth control valve, and the seventh control valve are controlled.

[0017] In some embodiments, when the operation mode is a conventional refrigeration mode, the seventh control valve is controlled to be opened, and the remaining control valves are controlled to be closed;

[0018] When the operation mode is a conventional heating mode, the seventh control valve is controlled to be opened, and the remaining control valves are controlled to be closed;

[0019] When the operation mode is the defrost mode, the first control valve and the second control valve are controlled to be opened, and the remaining control valves are controlled to be closed;

[0020] When the operation mode is the defrosting and heating mode, the first control valve, the second control valve and the fifth control valve are controlled to be opened, and the remaining control valves are controlled to be closed;

[0021] When the operation mode is a mode of reducing the refrigerant circulation amount, the fourth control valve and the sixth control valve are controlled to be opened, and the remaining control valves are controlled to be closed;

[0022] When the operation mode is a mode for increasing the refrigerant circulation amount, the third control valve is controlled to be opened, and the remaining control valves are controlled to be closed.

[0023] The present invention provides an air conditioning system and a control method thereof, which have the following beneficial effects:

[0024] When the air-conditioning system of the present application operates in the defrost mode, the first control valve and the second control valve are respectively controlled to open, and the gaseous high-temperature and high-pressure refrigerant discharged from the compressor enters the outdoor heat exchanger for condensation after being switched by the four-way valve. The gaseous refrigerant defrosts the outdoor heat exchanger during the condensation process, and the condensed liquid refrigerant enters the indoor heat exchanger for evaporation after being throttled by the throttling element. The evaporated gas-liquid mixed refrigerant enters the liquid storage tank through the second control valve, wherein the liquid refrigerant is temporarily stored in the liquid storage tank, and the gaseous refrigerant returns to the gas-liquid separator after the first control valve and the four-way valve are switched again, and then to the compressor to form a cycle. After defrosting is completed, the air-conditioning system runs the defrosting and heating mode. In the initial stage of this mode, the first control valve and the second control valve are still controlled to be opened respectively. The gaseous high-temperature and high-pressure refrigerant discharged from the compressor is reversed by the four-way valve, and then enters the liquid storage tank through the first control valve. The liquid refrigerant in the liquid storage tank is vaporized by relying on the high temperature of the gaseous refrigerant. At the same time, the high pressure of the gaseous refrigerant provides power to discharge the vaporized refrigerant from the liquid storage tank through the second control valve, thereby shortening the time for the refrigerant in the liquid storage tank to be discharged, reducing the time for the heating capacity to recover to the maximum output after defrosting, and improving the heating capacity. This is the air-conditioning system completing the refrigerant transfer with the help of the liquid storage tank. When the amount of refrigerant in the air-conditioning system is large during operation and it is necessary to reduce the refrigerant in the circulation loop, the first control valve or the second control valve can be controlled to open so that part of the refrigerant in the circulation loop is stored in the liquid storage tank; when the amount of refrigerant in the air-conditioning system is small during operation and it is necessary to increase the refrigerant in the circulation loop, the third control valve can be controlled to open so that the refrigerant in the liquid storage tank enters the gas-liquid separator through the third control valve, and the amount of refrigerant in the circulation loop will increase. This is the air-conditioning system completing the refrigerant adjustment with the help of the liquid storage tank. It can be seen that the present application realizes the refrigerant adjustment and refrigerant transfer functions by simply connecting a single liquid storage tank and an appropriate number of control valves with the components and pipelines of the air-conditioning system, thereby significantly simplifying the pipeline structure, reducing costs, and improving product space utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0026] Figure 1 is a schematic diagram of an air conditioning system according to an embodiment of the present invention;

[0027] Figure 2 It is a schematic diagram of the flow direction of the refrigerant when the air-conditioning system according to the embodiment of the present invention is in a conventional cooling mode;

[0028] Figure 3A schematic diagram of the flow direction of the refrigerant when the air-conditioning system according to an embodiment of the present invention is in a conventional heating mode;

[0029] Figure 4 It is a schematic diagram of the flow direction of the refrigerant when the air-conditioning system according to the embodiment of the present invention is in the defrosting mode;

[0030] Figure 5 A schematic diagram of the flow direction of the refrigerant when the air-conditioning system according to the embodiment of the present invention is in a defrosting and heating mode;

[0031] Figure 6 It is a schematic diagram of the refrigerant flow direction when the air-conditioning system according to an embodiment of the present invention is in a conventional cooling mode and the refrigerant is stored in the liquid storage tank;

[0032] Figure 7 It is a schematic diagram of the refrigerant flow direction when the air-conditioning system according to an embodiment of the present invention is in a conventional refrigeration mode and the refrigerant is stored in the liquid storage tank and the liquid storage tank needs to be exhausted to the gas-liquid separator to maintain air pressure balance;

[0033] Figure 8 It is a schematic diagram of the refrigerant flow direction when the liquid storage tank is discharging liquid to the gas-liquid separator in the air-conditioning system according to the embodiment of the present invention in the normal refrigeration mode;

[0034] Fig. 9 Schematic diagram of refrigerant flow direction when the air-conditioning system according to an embodiment of the present invention is in a conventional heating mode and the refrigerant is stored in the liquid storage tank;

[0035] Fig.10 It is a schematic diagram of the refrigerant flow direction when the air-conditioning system according to the embodiment of the present invention is in a conventional heating mode and the refrigerant is stored in the liquid storage tank and the liquid storage tank needs to be exhausted to the gas-liquid separator to maintain air pressure balance;

[0036] Fig.11 It is a schematic diagram of the refrigerant flow direction when the liquid storage tank discharges liquid to the gas-liquid separator when the air-conditioning system according to an embodiment of the present invention is in the conventional heating mode.

[0037] The reference numerals are as follows:

[0038] 1. Compressor; 2. Four-way valve; 3. Outdoor heat exchanger; 4. Throttling element; 5. Indoor heat exchanger; 6. Gas-liquid separator; 7. Liquid storage tank; 8. First control valve; 9. Second control valve; 10. Third control valve; 11. Fourth control valve; 12. Fifth control valve; 13. Sixth control valve; 14. Seventh control valve; 15. Oil separator. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0041] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0042] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0043] See also Figures 1 to 11As shown, according to an embodiment of the present invention, an air-conditioning system is provided, comprising: a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, a throttling element 4, an indoor heat exchanger 5, a gas-liquid separator 6 and a liquid storage tank 7. The compressor 1, the four-way valve 2, the outdoor heat exchanger 3, the throttling element 4, the indoor heat exchanger 5, and the gas-liquid separator 6 are connected by pipelines to form a refrigerant circulation loop. The four-way valve 2 has a first port, a second port, a third port and a fourth port. The first port is connected to the exhaust port of the compressor 1, the second port is connected to the outdoor heat exchanger 3, the third port is connected to the indoor heat exchanger 5, and the fourth port is connected to the inlet of the gas-liquid separator 6. The liquid storage tank 7 is connected between the third port and the indoor heat exchanger 5 through a first control valve 8, and the liquid storage tank 7 is also connected between the third port and the indoor heat exchanger 5 through a second control valve 9. The liquid storage tank 7 is also connected to the inlet of the gas-liquid separator 6 through a third control valve 10.

[0044] In this technical solution, when the air-conditioning system of the present application runs in the defrost mode, the first control valve 8 and the second control valve 9 are respectively controlled to open, and the gaseous high-temperature and high-pressure refrigerant discharged from the compressor 1 enters the outdoor heat exchanger 3 for condensation after being reversed by the four-way valve 2. The gaseous refrigerant defrosts the outdoor heat exchanger 3 during the condensation process. The condensed liquid refrigerant enters the indoor heat exchanger 5 for evaporation after being throttled by the throttling element 4. The evaporated gas-liquid mixed refrigerant enters the liquid storage tank 7 through the second control valve 9, wherein the liquid refrigerant is temporarily stored in the liquid storage tank 7. The gaseous refrigerant returns to the gas-liquid separator 6 through the first control valve 8 and the reversal of the four-way valve 2, and then to the compressor 1 to form a cycle. After defrosting is completed, the air-conditioning system runs the defrosting and heating mode. In the initial stage of this mode, the first control valve 8 and the second control valve 9 are still controlled to be opened respectively. The gaseous high-temperature and high-pressure refrigerant discharged from the compressor 1 is reversed by the four-way valve 2, and then enters the liquid storage tank 7 through the first control valve 8. The liquid refrigerant in the liquid storage tank 7 is vaporized by relying on the high temperature of the gaseous refrigerant. At the same time, the high pressure of the gaseous refrigerant provides power to discharge the vaporized refrigerant from the liquid storage tank 7 through the second control valve 9, thereby shortening the time for the refrigerant in the liquid storage tank 7 to be discharged, reducing the time for the heating capacity to recover to the maximum output after defrosting, and improving the heating capacity. This is the air-conditioning system completing the refrigerant transfer with the help of the liquid storage tank 7. When the amount of refrigerant in the air-conditioning system is large during operation and the refrigerant in the circulation loop needs to be reduced, the first control valve 8 or the second control valve 9 can be controlled to open so that part of the refrigerant in the circulation loop is stored in the liquid storage tank 7; when the amount of refrigerant in the air-conditioning system is small during operation and the refrigerant in the circulation loop needs to be increased, the third control valve 10 can be controlled to open so that the refrigerant in the liquid storage tank 7 enters the gas-liquid separator 6 through the third control valve 10, and the amount of refrigerant in the circulation loop will increase, which means that the air-conditioning system has completed the refrigerant adjustment with the help of the liquid storage tank 7. It can be seen that the present application realizes the refrigerant adjustment and refrigerant transfer functions by simply connecting a single liquid storage tank 7 and an appropriate number of control valves with the components and pipelines of the air-conditioning system, thereby significantly simplifying the pipeline structure, reducing costs, and improving product space utilization.

[0045] It should be noted that after the initial stage of the heating mode after defrosting is over, that is, after the liquid refrigerant in the liquid storage tank 7 is completely discharged into the refrigerant circulation loop, the first control valve 8 and the second control valve 9 can be controlled to close respectively, so that the high-temperature and high-pressure refrigerant discharged from the compressor 1 directly enters the indoor heat exchanger 5 for condensation after being reversed by the four-way valve 2, thereby restoring the air-conditioning system to the normal heating mode.

[0046] See also Figure 1 As shown, the liquid storage tank 7 is also connected between the outdoor heat exchanger 3 and the indoor heat exchanger 5 through a fourth control valve 11.

[0047] In this embodiment, when the air conditioning system operates in a conventional cooling mode, the high-temperature and high-pressure refrigerant discharged from the compressor 1 enters the outdoor heat exchanger 3 for condensation after the four-way valve 2 is switched, and then becomes a liquid medium-pressure refrigerant; when the air conditioning system operates in a conventional heating mode, the high-temperature and high-pressure refrigerant discharged from the compressor 1 enters the indoor heat exchanger 5 for condensation after the four-way valve 2 is switched, and then becomes a liquid medium-pressure refrigerant. That is, whether the air conditioning system is cooling or heating, the outdoor heat exchanger 3 and the indoor heat exchanger 5 are both medium-pressure sides, so the pressure difference between the medium-pressure side and the liquid storage tank 7 can be used to allow the refrigerant in the circulation loop to flow smoothly into the liquid storage tank 7. In other words, when the air conditioning system has a large amount of refrigerant during operation and needs to reduce the refrigerant in the circulation loop, the first control valve 8 and the second control valve 9 can be controlled to be closed, and the fourth control valve 11 can be controlled to be opened, so that the refrigerant in the circulation loop is stored in the liquid storage tank 7 through the fourth control valve 11.

[0048] See also Figure 1 As shown, the liquid storage tank 7 is also connected between the third port and the indoor heat exchanger 5 through the fifth control valve 12. Specifically, the first valve port of the fifth control valve 12 is connected to a position close to the bottom of the liquid storage tank 7, and the second valve port of the fifth control valve 12 is connected to between the third port and the indoor heat exchanger 5.

[0049] In this technical solution, after defrosting is completed, the air conditioning system runs the defrosting end heating mode. In the initial stage of this mode, the first control valve 8, the second control valve 9 and the fifth control valve 12 are respectively controlled to be opened, and the gaseous high-temperature and high-pressure refrigerant enters the liquid storage tank 7 through the first control valve 8. The high-temperature and high-pressure refrigerant provides power to make the refrigerant in the liquid storage tank 7 be discharged into the circulation loop through the second control valve 9 and the fifth control valve 12, thereby further shortening the time for the refrigerant in the liquid storage tank 7 to be discharged. Moreover, the end of the fifth control valve 12 away from the refrigerant circulation loop is connected to a position close to the bottom of the liquid storage tank 7, which is also conducive to the efficient discharge of the liquid refrigerant in the liquid storage tank 7 and the discharge is cleaner. It should be noted that the end of the second control valve 9 away from the liquid storage tank 7 is between the end of the first control valve 8 away from the liquid storage tank 7 and the indoor heat exchanger 5, and the end of the fifth control valve 12 away from the liquid storage tank 7 is between the end of the second control valve 9 away from the liquid storage tank 7 and the indoor heat exchanger 5.

[0050] See also Figure 1 As shown, the first valve port of the first control valve 8 is connected to the top of the liquid storage tank 7 ; and / or, the first valve port of the second control valve 9 is connected to the top of the liquid storage tank 7 .

[0051] In this embodiment, when the air conditioning system operates in different modes, the gaseous refrigerant in the liquid storage tank 7 will be discharged into the circulation loop through the first control valve 8 or the second control valve 9. Therefore, when the first valve port of the first control valve 8 is connected to the top of the liquid storage tank 7 and the first valve port of the second control valve 9 is also connected to the top of the liquid storage tank 7, it is more conducive to the smooth discharge of the gaseous refrigerant in the liquid storage tank 7. In addition, the first valve port of the first control valve 8 and the first valve port of the second control valve 9 can also be connected to a position close to the top of the liquid storage tank 7.

[0052] See also Figure 4 As shown, the first valve port of the third control valve 10 is connected to a position near the bottom of the liquid storage tank 7. When the amount of refrigerant in the refrigerant circulation loop is small, since the third control valve 10 is used to control the refrigerant in the liquid storage tank 7 to enter the gas-liquid separator 6, thereby controlling the increase in the amount of refrigerant in the refrigerant circulation loop, when the first valve port of the third control valve 10 is connected to a position near the bottom of the liquid storage tank 7, it is beneficial to quickly discharge the liquid refrigerant in the liquid storage tank 7 into the gas-liquid separator 6, thereby improving the efficiency of adding the amount of refrigerant to the refrigerant circulation loop.

[0053] See also Figure 1 As shown, the air conditioning system also includes a sixth control valve 13, a first valve port of the sixth control valve 13 is connected between the liquid storage tank 7 and the first control valve 8, and a second valve port of the sixth control valve 13 is connected between the third control valve 10 and the inlet of the gas-liquid separator 6.

[0054] In this embodiment, when the refrigerant in the refrigerant circulation loop flows into the liquid storage tank 7 through the fourth control valve 11, and as the amount of refrigerant in the liquid storage tank 7 increases, the pressure in the tank body will also increase, which will hinder the inflow of the refrigerant. By setting the sixth control valve 13, the gaseous refrigerant in the liquid storage tank 7 can be introduced into the gas-liquid separator 6 at an appropriate time, thereby reducing the pressure in the tank body and ensuring that the refrigerant in the circulation loop can always flow smoothly into the liquid storage tank 7 through the fourth control valve 11. It can be understood that the amount of liquid refrigerant flowing in through the fourth control valve 11 is greater than the amount of gaseous refrigerant discharged through the sixth control valve 13, so the opening of the sixth control valve 13 will not lead to an increase in the amount of refrigerant in the refrigerant circulation loop.

[0055] See also Figure 1 As shown, the second valve port of the first control valve 8 is connected to the first node of the refrigerant circulation loop, the second valve port of the second control valve 9 is connected to the second node of the refrigerant circulation loop, and a seventh control valve 14 is provided in the refrigerant circulation loop, and the seventh control valve 14 is located between the first node and the second node.

[0056] In this embodiment, when the air conditioning system is running in defrosting mode or defrosting end heating mode, by controlling the seventh control valve 14 to close and controlling the first control valve 8 and the second control valve 9 to open, it can be ensured that the refrigerant in the refrigerant circulation loop completely flows through the liquid storage tank 7, and there is no diversion. When the air conditioning system is running in conventional cooling or heating mode, by controlling the seventh control valve 14 to open and controlling the remaining control valves to close, the normal circulation of the refrigerant in the refrigerant circulation loop can be ensured. It should also be noted that the above control valves can be commercially available solenoid valves or electric valves, and the liquid storage tank 7 can be installed in both the indoor unit and the outdoor unit of the air conditioning system through the connection relationship between each control valve and the refrigerant circulation loop, and its installation position is relatively flexible. The liquid storage tank 7 can be provided with two top inlets and outlets at the top, and the first valve port of the first control valve 8 and the first valve port of the second control valve 9 are respectively connected to the two top inlets and outlets. The liquid storage tank 7 can also be provided with a bottom inlet and outlet near the bottom, and the first valve port of the third control valve 10, the first valve port of the fourth control valve 11, and the first valve port of the fifth control valve 12 can all be connected to the bottom inlet and outlet.

[0057] See also Figure 1 As shown, an oil separator 15 is also provided in the refrigerant circulation circuit, and the oil separator 15 is located between the exhaust port of the compressor 1 and the first port of the four-way valve 2 .

[0058] In this technical solution, the lubricating oil in the refrigerant discharged from the compressor 1 can be separated by providing an oil separator 15 to prevent the lubricating oil from being distributed in the entire circulation loop along with the refrigerant.

[0059] The present application also provides a control method for an air conditioning system, which is used to control the operation of the aforementioned air conditioning system, and the control method includes:

[0060] Get the operation mode of the air conditioning system;

[0061] The opening and closing of the first control valve 8 , the second control valve 9 , the third control valve 10 , the fourth control valve 11 , the fifth control valve 12 , the sixth control valve 13 and the seventh control valve 14 are controlled according to the operation mode.

[0062] When the operation mode is the normal cooling mode, the seventh control valve 14 is controlled to be open, and the other control valves are controlled to be closed. Then the high-temperature and high-pressure refrigerant discharged from the compressor 1 enters the outdoor heat exchanger 3 for condensation after the four-way valve 2 is switched. The condensed refrigerant enters the indoor heat exchanger 5 for evaporation after throttling by the throttling element 4. The evaporated refrigerant enters the gas-liquid separator 6 through the seventh control valve 14 and the four-way valve 2 again, and then returns to the compressor 1 to form a cycle. Figure 2 shown.

[0063] When the operation mode is the conventional heating mode, the seventh control valve 14 is controlled to be open, and the other control valves are controlled to be closed. Then the high-temperature and high-pressure refrigerant discharged from the compressor 1 enters the indoor heat exchanger 5 for condensation through the four-way valve 2 reversal and the seventh control valve 14. The condensed refrigerant enters the outdoor heat exchanger 3 for evaporation after being throttled by the throttling element 4. The evaporated refrigerant enters the gas-liquid separator 6 through the four-way valve 2 reversal again, and then returns to the compressor 1 to form a cycle. Figure 3 shown.

[0064] When the operation mode is the defrost mode, the first control valve 8 and the second control valve 9 are controlled to be open, and the other control valves are controlled to be closed. Then the gaseous high-temperature and high-pressure refrigerant discharged from the compressor 1 enters the outdoor heat exchanger 3 for condensation after being switched by the four-way valve 2. The gaseous refrigerant defrosts the outdoor heat exchanger 3 during the condensation process. The condensed liquid refrigerant enters the indoor heat exchanger 5 for evaporation after being throttled by the throttling element 4. The evaporated gas-liquid mixed refrigerant enters the liquid storage tank 7 through the second control valve 9, where the liquid refrigerant is temporarily stored in the liquid storage tank 7. The gaseous refrigerant returns to the gas-liquid separator 6 through the first control valve 8 and the switching of the four-way valve 2 again, and then to the compressor 1 to form a cycle, such as Figure 4 shown.

[0065] When the operation mode is defrosting and heating mode, the first control valve 8, the second control valve 9, and the fifth control valve 12 are controlled to open, and the remaining control valves are controlled to close. Then the high-temperature and high-pressure refrigerant discharged from the compressor 1 enters the liquid storage tank 7 through the four-way valve 2 reversing and the first control valve 8. The high pressure of the gaseous refrigerant provides power to make the refrigerant in the liquid storage tank 7 pass through the second control valve 9 and the fifth control valve 12 to discharge the liquid storage tank 7 and enter the indoor heat exchanger 5 for condensation. The condensed refrigerant enters the outdoor heat exchanger 3 for evaporation after throttling by the throttling element 4. The evaporated refrigerant enters the gas-liquid separator 6 after reversing the four-way valve 2 again, and then returns to the compressor 1 to form a cycle. Figure 5 shown.

[0066] When the operation mode is to reduce the refrigerant circulation mode, the fourth control valve 11 and the sixth control valve 13 are controlled to be open, and the other control valves are controlled to be closed. Then the liquid refrigerant in the refrigerant circulation loop is stored in the liquid storage tank 7 through the fourth control valve 11, and the gaseous refrigerant in the liquid storage tank 7 enters the gas-liquid separator 6 through the sixth control valve 13, thereby ensuring the air pressure balance in the liquid storage tank 7 and ensuring the smooth flow of liquid refrigerant. For details, please refer to Figure 7 and Fig.10 The amount of refrigerant in the refrigerant circulation system can be reduced when the air-conditioning system is heating or when the air-conditioning system is cooling.

[0067] When the operation mode is to increase the refrigerant circulation volume mode, the third control valve 10 is controlled to open, and the other control valves are controlled to close. Then the liquid refrigerant in the liquid storage tank 7 enters the gas-liquid separator 6 through the third control valve 10, thereby increasing the refrigerant volume in the circulation loop. For details, see Figure 8 and Fig.11 Increasing the amount of refrigerant in the refrigerant circulation system can be performed when the air-conditioning system is heating or when the air-conditioning system is cooling.

[0068] It is easy for those skilled in the art to understand that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0069] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention. The above are only preferred embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention, and these improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. An air conditioning system, characterized in that: The invention comprises a compressor (1), a four-way valve (2), an outdoor heat exchanger (3), an indoor heat exchanger (5), a gas-liquid separator (6) and a liquid storage tank (7); the compressor (1), the four-way valve (2), the outdoor heat exchanger (3), the indoor heat exchanger (5) and the gas-liquid separator (6) are connected by pipelines to form a refrigerant circulation loop; the four-way valve (2) has a first port, a second port, a third port and a fourth port; the first port is connected to the exhaust port of the compressor (1); the second port is connected to the outdoor heat exchanger (3); the third port is connected to the indoor heat exchanger (5); the fourth port is connected to the inlet of the gas-liquid separator (6); the liquid storage tank (7) is connected between the third port and the indoor heat exchanger (5) through a first control valve (8); the liquid storage tank (7) is also connected between the third port and the indoor heat exchanger (5) through a second control valve (9); and the liquid storage tank (7) is also connected to the inlet of the gas-liquid separator (6) through a third control valve (10).

2. The air conditioning system according to claim 1, characterized in that: The liquid storage tank (7) is also connected between the outdoor heat exchanger (3) and the indoor heat exchanger (5) via a fourth control valve (11).

3. The air conditioning system according to claim 1, characterized in that: The liquid storage tank (7) is also connected between the third port and the indoor heat exchanger (5) via a fifth control valve (12), and a first valve port of the fifth control valve (12) is connected to a position close to the bottom of the liquid storage tank (7).

4. The air conditioning system according to claim 1, characterized in that: The first valve port of the first control valve (8) is connected to the top of the liquid storage tank (7); and / or the first valve port of the second control valve (9) is connected to the top of the liquid storage tank (7).

5. The air conditioning system according to claim 1, characterized in that: The first valve port of the third control valve (10) is connected to a position close to the bottom of the liquid storage tank (7).

6. The air conditioning system according to claim 1, characterized in that: It also includes a sixth control valve (13), wherein a first valve port of the sixth control valve (13) is connected between the liquid storage tank (7) and the first control valve (8), and a second valve port of the sixth control valve (13) is connected between the third control valve (10) and the inlet of the gas-liquid separator (6).

7. The air conditioning system according to any one of claims 1 to 6, characterized in that: The second valve port of the first control valve (8) is connected to the first node of the refrigerant circulation loop, and the second valve port of the second control valve (9) is connected to the second node of the refrigerant circulation loop. A seventh control valve (14) is provided in the refrigerant circulation loop, and the seventh control valve (14) is located between the first node and the second node.

8. The air conditioning system according to claim 1, characterized in that: An oil separator (15) is also provided in the refrigerant circulation circuit, and the oil separator (15) is located between the exhaust port of the compressor (1) and the first port.

9. A method for controlling an air conditioning system, characterized in that: For controlling the operation of the air conditioning system according to claim 7, the control method comprises: Obtaining an operating mode of the air conditioning system; According to the operating mode, the opening and closing of the first control valve (8), the second control valve (9), the third control valve (10), the fourth control valve (11), the fifth control valve (12), the sixth control valve (13) and the seventh control valve (14) are controlled.

10. The control method according to claim 9, characterized in that: When the operation mode is a conventional refrigeration mode, the seventh control valve (14) is controlled to be opened, and the remaining control valves are controlled to be closed; When the operation mode is a conventional heating mode, the seventh control valve (14) is controlled to be open, and the remaining control valves are controlled to be closed; When the operation mode is a defrosting mode, the first control valve (8) and the second control valve (9) are controlled to be opened, and the remaining control valves are controlled to be closed; When the operation mode is a defrosting and heating mode, the first control valve (8), the second control valve (9) and the fifth control valve (12) are controlled to be open, and the remaining control valves are controlled to be closed; When the operation mode is a mode of reducing the refrigerant circulation amount, the fourth control valve (11) and the sixth control valve (13) are controlled to be opened, and the remaining control valves are controlled to be closed; When the operation mode is a mode for increasing the refrigerant circulation amount, the third control valve (10) is controlled to be opened, and the remaining control valves are controlled to be closed.

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