Air conditioning system

Abstract

The utility model provides an air conditioning system which 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, 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, and the second port is connected to an exhaust port of the indoor heat exchanger. 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, 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, and the liquid storage tank is further connected to an inlet of the gas-liquid separator through the third control valve. According to the utility model, the functions of refrigerant adjustment and refrigerant transfer 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 an 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 utility model belongs to the technical field of air conditioning, and in particular relates to an air conditioning system. 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 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 discharge of liquid refrigerant through the drain pipe of the vapor-liquid separator, shortens the time for the liquid refrigerant of the vapor-liquid separator to be discharged, reduces the time for the heating capacity to recover to the maximum output after defrost, and improves the heating capacity. This function can be simply 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 simply referred to as the refrigerant adjustment function.

[0004] However, the existing technology does not have a method of simply adding a tank and an appropriate number of control valves to the air-conditioning system and connecting them to the components and pipes in the air-conditioning system to simultaneously realize the refrigerant transfer and refrigerant adjustment functions. This makes this technical gap an important direction for optimizing the air-conditioning system. Utility Model Content

[0005] Therefore, the utility model 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 body 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 utility model 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, four-way valve, outdoor heat exchanger, indoor heat exchanger and 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, and 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, and the liquid storage tank is also connected between the third port and the indoor heat exchanger through a second control valve. 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 via 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.

[0010] In some embodiments, the first valve port of the second control valve is connected to the top of the liquid storage tank.

[0011] 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.

[0012] 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 the inlet of the gas-liquid separator.

[0013] 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, and 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.

[0014] 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.

[0015] The utility model provides an air conditioning system with the following beneficial effects:

[0016] When the air-conditioning system of the present application operates in the defrost mode, the first control valve and the second control valve are controlled to open respectively, and the gaseous high-temperature and high-pressure refrigerant discharged from the compressor enters the outdoor heat exchanger for condensation after being reversed by the four-way valve. The gaseous refrigerant defrosts the outdoor heat exchanger during the condensation process. 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, where the liquid refrigerant is temporarily stored in the liquid storage tank. The gaseous refrigerant returns to the gas-liquid separator after being reversed again by the first control valve and the four-way valve, and then to the compressor to form a cycle. After the defrost is completed, the air-conditioning system runs the defrost end 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 through 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 the refrigerant in the circulation loop needs to be reduced, 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 the refrigerant in the circulation loop needs to be increased, 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 adding a single liquid storage tank and an appropriate number of control valves and simply connecting them 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

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are merely exemplary, and those skilled in the art can, without inventive effort, derive other implementation drawings based on the provided drawings.

[0018] Figure 1 A schematic diagram of an air conditioning system according to an embodiment of the present invention;

[0019] Figure 2 This 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;

[0020] Figure 3 This is a schematic diagram of the refrigerant flow when the air-conditioning system according to the embodiment of the present invention is in a conventional heating mode;

[0021] Figure 4 This 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 defrost mode;

[0022] Figure 5 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 and heating mode;

[0023] Figure 6 This 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 cooling mode and the refrigerant is stored in the liquid storage tank;

[0024] Figure 7 This 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 cooling mode and 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;

[0025] Figure 8 This is a schematic diagram of the refrigerant flow direction when the air-conditioning system according to the embodiment of the present utility model is in the normal refrigeration mode and the liquid storage tank is discharging liquid to the gas-liquid separator;

[0026] Figure 9 This 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;

[0027] Figure 10 This 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 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;

[0028] Figure 11 This is a schematic diagram of the refrigerant flow when the liquid storage tank is discharging liquid to the gas-liquid separator when the air-conditioning system according to an embodiment of the present utility model is in conventional heating mode.

[0029] The reference numerals indicate:

[0030] 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

[0031] 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 embodiments described are only some embodiments of the present invention, not all embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way 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 making creative efforts are within the scope of protection of the present invention.

[0032] In the description of the present invention, it needs to be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, 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 device or element 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 outline of each component itself.

[0033] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. 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 figures. For example, if the device in the 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.

[0034] In addition, it should be noted that the use of words such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above words have no special meaning and therefore cannot be understood as limiting the scope of protection of this utility model.

[0035] See also Figures 1 to 11As shown, according to an embodiment of the present utility model, an air-conditioning system is provided, including: 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.

[0036] In this technical solution, when the air-conditioning system of the present application operates in the defrost mode, the first control valve 8 and the second control valve 9 are controlled to open respectively, 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 throttling 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 after the first control valve 8 and the four-way valve 2 are reversed again, and then to the compressor 1 to form a cycle. After the 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 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 through 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. This is the air-conditioning system completing 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 adding a single liquid storage tank 7 and an appropriate number of control valves and simply connecting them with the components and pipelines of the air-conditioning system, thereby significantly simplifying the pipeline structure, reducing costs, and improving product space utilization.

[0037] It should be noted that after the initial stage of the heating mode after defrosting is completed, 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 by the compressor 1 is directly transferred to 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.

[0038] 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 .

[0039] In this embodiment, when the air conditioning system operates in conventional cooling mode, the high-temperature, high-pressure refrigerant discharged from the compressor 1 is diverted by the four-way valve 2 and then enters the outdoor heat exchanger 3 for condensation, before becoming a liquid medium-pressure refrigerant. When the air conditioning system operates in conventional heating mode, the high-temperature, high-pressure refrigerant discharged from the compressor 1 is diverted by the four-way valve 2 and then enters the indoor heat exchanger 5 for condensation, before becoming a liquid medium-pressure refrigerant. That is, whether the air conditioning system is cooling or heating, the area between the outdoor heat exchanger 3 and the indoor heat exchanger 5 is at medium pressure. Therefore, the pressure differential between the medium pressure area and the liquid storage tank 7 can be utilized to ensure smooth flow of refrigerant in the circulating loop into the liquid storage tank 7. In other words, when the air conditioning system experiences a high refrigerant volume during operation and needs to reduce the amount of refrigerant in the circulating loop, the first and second control valves 8 and 9 can be closed, and the fourth control valve 11 can be opened, allowing the refrigerant in the circulating loop to be stored in the liquid storage tank 7 via the fourth control valve 11.

[0040] See also Figure 1 As shown, the liquid storage tank 7 is further connected between the third port and the indoor heat exchanger 5 via a fifth control valve 12. Specifically, a first valve port of the fifth control valve 12 is connected to a position near the bottom of the liquid storage tank 7, and a second valve port of the fifth control valve 12 is connected between the third port and the indoor heat exchanger 5.

[0041] In this technical solution, after defrosting is completed, the air conditioning system operates in a defrost-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 controlled to open, respectively. Then, 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 discharge the refrigerant in the liquid storage tank 7 into the circulation loop through the second control valve 9 and the fifth control valve 12, further shortening the time it takes for the refrigerant in the liquid storage tank 7 to be discharged. Furthermore, the end of the fifth control valve 12 that is remote from the refrigerant circulation loop is connected to a position near the bottom of the liquid storage tank 7, which also facilitates efficient and cleaner discharge of the liquid refrigerant in the liquid storage tank 7. It should be noted that the end of the second control valve 9 that is remote from the liquid storage tank 7 is located between the end of the first control valve 8 that is remote from the liquid storage tank 7 and the indoor heat exchanger 5, and the end of the fifth control valve 12 that is remote from the liquid storage tank 7 is located between the end of the second control valve 9 that is remote from the liquid storage tank 7 and the indoor heat exchanger 5.

[0042] 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 .

[0043] In this embodiment, since the gaseous refrigerant in the liquid storage tank 7 is discharged into the circulation loop through the first control valve 8 or the second control valve 9 when the air-conditioning system operates in different modes, 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 near the top of the liquid storage tank 7.

[0044] 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 increasing the amount of refrigerant in the refrigerant circulation loop.

[0045] 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.

[0046] 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 providing 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. Therefore, opening the sixth control valve 13 will not cause the amount of refrigerant in the refrigerant circulation loop to increase.

[0047] 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.

[0048] In this embodiment, when the air conditioning system is operating in defrost mode or defrost-end heating mode, the seventh control valve 14 is controlled to close and the first control valve 8 and the second control valve 9 are controlled to open, thereby ensuring that the refrigerant in the refrigerant circulation loop flows completely through the liquid storage tank 7, preventing diversion. When the air conditioning system is operating in normal cooling or heating mode, the seventh control valve 14 is controlled to open and the remaining control valves are controlled to close, thereby ensuring normal circulation of the refrigerant in the refrigerant circulation loop. It should also be noted that each of the above control valves can be a commercially available solenoid valve or electric valve. The connection between the liquid storage tank 7 and the refrigerant circulation loop through each control valve allows the liquid storage tank 7 to be installed in either the indoor unit or the outdoor unit of the air conditioning system, providing flexibility in its installation location. The liquid storage tank 7 can be provided with two top inlets and outlets at the top, with the first valve port of the first control valve 8 and the first valve port of the second control valve 9 connected to the two top inlets and outlets, respectively. The liquid storage tank 7 can also be provided with a bottom inlet and outlet near the bottom, to which 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.

[0049] See also Figure 1 As shown, an oil separator 15 is further provided in the refrigerant circulation circuit. The oil separator 15 is located between the exhaust port of the compressor 1 and the first port of the four-way valve 2 .

[0050] 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.

[0051] The present application also provides a control method for an air-conditioning system, for controlling the operation of the aforementioned air-conditioning system, the control method comprising:

[0052] Get the operating mode of the air conditioning system;

[0053] 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.

[0054] When the operating mode is the normal cooling mode, the seventh control valve 14 is controlled to open and the other control valves are controlled to close. Then the 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 condensed refrigerant is throttled by the throttling element 4 and enters the indoor heat exchanger 5 for evaporation. The evaporated refrigerant enters the gas-liquid separator 6 after being reversed again by the seventh control valve 14 and the four-way valve 2, and then returns to the compressor 1 to form a cycle. Figure 2 shown.

[0055] When the operation mode is the normal heating mode, the seventh control valve 14 is controlled to open and the other control valves are controlled to close. Then the high-temperature and high-pressure refrigerant discharged from the compressor 1 enters the indoor heat exchanger 5 through the switching of the four-way valve 2 and the seventh control valve 14 to be condensed. The condensed refrigerant is throttled by the throttling element 4 and then enters the outdoor heat exchanger 3 to evaporate. The evaporated refrigerant is reversed again by the four-way valve 2 and enters the gas-liquid separator 6, and then returns to the compressor 1 to form a cycle. Figure 3 shown.

[0056] When the operation mode is defrost mode, the first control valve 8 and the second control valve 9 are controlled to open, and the other control valves are controlled to close. Then 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 is throttled by the throttling element 4 and enters the indoor heat exchanger 5 for evaporation. 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 four-way valve 2 again, and then returns to the compressor 1 to form a cycle. Figure 4 shown.

[0057] When the operation mode is defrost end heating mode, the first control valve 8, the second control valve 9, and the fifth control valve 12 are controlled to open, and the other 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 be discharged from the liquid storage tank 7 through the second control valve 9 and the fifth control valve 12 and enter the indoor heat exchanger 5 for condensation. The condensed refrigerant is throttled by the throttling element 4 and then enters the outdoor heat exchanger 3 for evaporation. The evaporated refrigerant is reversed again by the four-way valve 2 and enters the gas-liquid separator 6, and then returns to the compressor 1 to form a cycle. Figure 5 shown.

[0058] When the operation mode is to reduce the refrigerant circulation volume, the fourth control valve 11 and the sixth control valve 13 are controlled to open, and the other control valves are controlled to close. 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 pressure balance in the liquid storage tank 7 and ensuring the smooth flow of liquid refrigerant. For details, please refer to Figure 7 and Figure 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.

[0059] When the operation mode is to increase the refrigerant circulation mode, the third control valve 10 is controlled to open and the other control valves are controlled to close. 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 amount in the circulation loop. For details, please refer to Figure 8 and Figure 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.

[0060] It is easy for those skilled in the art to understand that, under the premise of no conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0061] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention. The above are only preferred embodiments of the present invention. It should be noted that for those skilled in the art, several improvements and variations can be made without departing from the technical principles of the present invention, and such improvements and variations shall also be considered within the scope of protection 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 through a pipeline 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). 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).

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).

5. The air conditioning system according to claim 1, characterized in that The first valve port of the second control valve (9) is connected to the top of the liquid storage tank (7).

6. 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).

7. The air conditioning system according to claim 1, characterized in that The invention 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).

8. The air conditioning system according to claim 1, 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.

9. 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.

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