Air conditioning systems and their control methods

Abstract

This invention provides an air conditioning system and its control method. The air conditioning system includes a compressor, an outdoor heat exchanger, an indoor heat exchanger, a gas-liquid separator, and a refrigerant storage container. The compressor, outdoor heat exchanger, indoor heat exchanger, and gas-liquid separator form a refrigerant circulation loop. The refrigerant storage container is controllably connected to the gas-liquid separator. According to this invention, because a refrigerant storage container is added to the air conditioning system and is controllably connected to the gas-liquid separator, when there is a large amount of liquid refrigerant in the gas-liquid separator, the refrigerant storage container can be connected to the gas-liquid separator, and then most of the liquid refrigerant in the gas-liquid separator can be transferred to the refrigerant storage container. Thus, when defrosting the outdoor heat exchanger, it is not necessary to heat the liquid refrigerant in the gas-liquid separator, thereby increasing the compressor's suction and discharge temperatures, ensuring the refrigerant temperature entering the outdoor heat exchanger, and ultimately helping to shorten the defrosting time.

Description

Technical Field

[0001] This invention belongs to the field of air conditioning technology, specifically relating to an air conditioning system and its control method. Background Technology

[0002] Air-cooled central air conditioning units are widely used, including multi-split systems, ducted systems, residential units, and modular units. The outdoor units of these central air conditioning systems all use finned heat exchangers. Finned heat exchangers are prone to frosting during winter heating, and the more frosting, the less refrigerant flows in the unit, with excess refrigerant stored in a liquid form in the vapor-liquid separator. The unit typically defrosts by reversing the flow of high-temperature, high-pressure refrigerant discharged from the compressor into the finned heat exchanger. Furthermore, defrosting requires heating and evaporating all the low-temperature liquid refrigerant in the vapor-liquid separator. However, this lowers the compressor's suction and discharge temperatures, consequently lowering the temperature of the refrigerant entering the finned heat exchanger and delaying the defrosting time. Summary of the Invention

[0003] Therefore, the present invention provides an air conditioning system that can solve the technical problem that, during the defrosting of an air conditioning unit, in addition to allowing the high-temperature and high-pressure refrigerant discharged from the compressor to flow back into the finned heat exchanger, it is also necessary to heat and evaporate all the low-temperature liquid refrigerant in the vapor-liquid separator. However, this would reduce the compressor's suction and discharge temperatures, and also reduce the temperature of the refrigerant entering the finned heat exchanger, thereby delaying the defrosting time of the unit.

[0004] To address the aforementioned problems, the present invention provides an air conditioning system comprising a compressor, an outdoor heat exchanger, an indoor heat exchanger, a gas-liquid separator, and a refrigerant storage container. The compressor, outdoor heat exchanger, indoor heat exchanger, and gas-liquid separator form a refrigerant circulation loop, and the refrigerant storage container is controllably connected to the gas-liquid separator.

[0005] In some embodiments, the gas-liquid separator is positioned higher than the refrigerant storage container, and a first control valve is provided in the flow path between the gas-liquid separator and the refrigerant storage container.

[0006] In some embodiments, the air conditioning system further includes a four-way valve having a first valve port, a second valve port, a third valve port, and a fourth valve port, wherein the first valve port is connected to the compressor, the second valve port is connected to the outdoor heat exchanger, the third valve port is connected to the indoor heat exchanger, and the fourth valve port is connected to the gas-liquid separator.

[0007] In some embodiments, a throttling element is provided in the flow path between the indoor heat exchanger and the outdoor heat exchanger, and the refrigerant storage container is connected to the flow path between the throttling element and the indoor heat exchanger via a second control valve.

[0008] In some embodiments, a throttling element is provided in the flow path between the indoor heat exchanger and the outdoor heat exchanger, and the refrigerant temporary storage container is connected to the flow path between the throttling element and the outdoor heat exchanger via a third control valve.

[0009] The present invention also provides a control method for controlling the operation of the aforementioned air conditioning system, the control method comprising:

[0010] The outdoor temperature is recorded as t1;

[0011] Based on t1 and t a The size relationship controls the opening and closing of the first control valve;

[0012] Among them, t a Set the first temperature value.

[0013] In some implementations, when t1 < t a At that time, the first control valve is turned on.

[0014] In some implementations, the temperature of the outdoor heat exchanger is recorded as t2, when t a ≤t1≤t b And t2 < t1 - t c When, the first control valve is turned on; wherein, t b For the second temperature setpoint, t a <t b , t c Set the third temperature value.

[0015] In some implementations, when t2 < t1 - t c -t d When the first control valve is shut off, the air conditioning system is controlled to operate in defrost mode; wherein, t d Set the fourth temperature value.

[0016] In some embodiments, when the air conditioning system is operating in defrost mode, the air conditioning system further includes a throttling element and a second control valve. When the opening degree of the throttling element is greater than a first set opening degree, the second control valve is controlled to open and then cut off after a first set time.

[0017] In some embodiments, after a second set time period, the opening of the throttling element continues to increase, controlling the second control valve to open and then controlling the second control valve to close after the first set time period.

[0018] In some embodiments, when the air conditioning system is operating in heating mode, the air conditioning system further includes a throttling element and a third control valve. When the opening degree of the throttling element is greater than a second set opening degree, the first control valve is controlled to shut off, the third control valve is controlled to open, and after a third set time period, the third control valve is controlled to shut off.

[0019] In some implementations, after a fourth set time period, the opening of the throttling element continues to increase, controlling the third control valve to open and then controlling the third control valve to close after the third set time period.

[0020] The air conditioning system and its control method provided by this invention have the following beneficial effects:

[0021] Because the air conditioning system of this application includes a refrigerant storage container, and this container is controllably connected to the gas-liquid separator, when there is a large amount of liquid refrigerant in the gas-liquid separator, the refrigerant storage container can be connected to the separator, and most of the liquid refrigerant in the separator can be transferred to the storage container. This eliminates the need to heat the liquid refrigerant in the gas-liquid separator during defrosting of the outdoor heat exchanger, thereby increasing the compressor's suction and discharge temperatures and ensuring the refrigerant temperature entering the outdoor heat exchanger, ultimately helping to shorten the unit's defrosting time.

[0022] Meanwhile, when the air conditioning system operates in low temperatures during winter, the lower the ambient temperature, the smaller the flow rate of refrigerant participating in the circulation, and the more liquid refrigerant is stored in the gas-liquid separator. However, when the unit stops and restarts at low ambient temperatures, the pressure difference between the high and low pressures is small for a short period, insufficient to drive the refrigerant flow. In this situation, the compressor may draw liquid refrigerant into itself through the oil return port on the gas-liquid separator, posing a risk of liquid slugging. By installing a refrigerant storage container, liquid refrigerant can be transferred to this container, preventing it from being drawn into the compressor when it starts, thus avoiding liquid slugging.

[0023] Furthermore, by adding a refrigerant storage container that is controllably connected to the gas-liquid separator, and introducing the low-pressure liquid refrigerant from the gas-liquid separator into the refrigerant storage container, the gas-liquid separator can be designed to be smaller. The newly added refrigerant storage container can be any shape that is easy to install, such as a pipeline type, thereby reducing the unit size. Attached Figure Description

[0024] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of an air conditioning system according to an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the refrigerant flow direction when the liquid refrigerant in the gas-liquid separator of the air conditioning system according to an embodiment of the present invention is stored in a refrigerant temporary storage container.

[0027] Figure 3 This is a schematic diagram of the refrigerant flow direction when the air conditioning system is in defrosting mode according to an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of the refrigerant flow direction when the air conditioning system of this invention is in defrost mode and the refrigerant storage container is replenishing refrigerant into the system.

[0029] Figure 5 This is a schematic diagram of the refrigerant flow direction when the air conditioning system is operating in heating mode according to an embodiment of the present invention;

[0030] Figure 6 This is a schematic diagram of the refrigerant flow direction when the air conditioning system is operating in heating mode and the refrigerant storage container is replenishing refrigerant into the system, according to an embodiment of the present invention.

[0031] Figure 7 This is a schematic diagram of the refrigerant flow direction when the air conditioning system is operating in cooling mode according to an embodiment of the present invention.

[0032] The reference numerals in the attached figures are as follows:

[0033] 1. Compressor; 2. Outdoor heat exchanger; 3. Indoor heat exchanger; 4. Gas-liquid separator; 5. Refrigerant storage container; 6. First control valve; 7. Four-way valve; 8. Throttling element; 9. Second control valve; 10. Third control valve; 11. Oil return port. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0036] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0037] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0038] See also Figures 1 to 7As shown, according to an embodiment of the present invention, an air conditioning system is provided, including a compressor 1, an outdoor heat exchanger 2, an indoor heat exchanger 3, a gas-liquid separator 4, and a refrigerant storage container 5. The compressor 1, the outdoor heat exchanger 2, the indoor heat exchanger 3, and the gas-liquid separator 4 form a refrigerant circulation loop, and the refrigerant storage container 5 is controllably connected to the gas-liquid separator 4.

[0039] In this technical solution, because a refrigerant storage container 5 is added to the air conditioning system of this application, and the refrigerant storage container 5 is controllably connected to the gas-liquid separator 4, when there is a large amount of liquid refrigerant in the gas-liquid separator 4, the refrigerant storage container 5 can be connected to the gas-liquid separator 4, and then most of the liquid refrigerant in the gas-liquid separator 4 can be transferred to the refrigerant storage container 5. Thus, when defrosting the outdoor heat exchanger 2, it is not necessary to heat the liquid refrigerant in the gas-liquid separator 4, thereby increasing the suction and discharge temperatures of the compressor 1, ensuring the refrigerant temperature entering the outdoor heat exchanger 2, and ultimately helping to shorten the defrosting time of the unit. The outdoor heat exchanger 2 is a finned heat exchanger.

[0040] Meanwhile, when the air conditioning system operates in low temperatures during winter, the lower the ambient temperature, the smaller the flow rate of refrigerant participating in the circulation, and the more liquid refrigerant is stored in the gas-liquid separator 4. However, when the unit stops and restarts at low ambient temperatures, the high and low pressure difference is small for a short period, insufficient to drive the refrigerant flow. At this time, the compressor may draw liquid refrigerant into the compressor 1 through the oil return port 11 on the gas-liquid separator 4, posing a risk of liquid slugging to the compressor 1. By setting up a refrigerant temporary storage container 5, the liquid refrigerant can be transferred to the refrigerant temporary storage container 5, thus preventing liquid refrigerant from being drawn into the compressor 1 when it starts, thereby avoiding liquid slugging.

[0041] Furthermore, by adding a refrigerant storage container 5 that is controllably connected to the gas-liquid separator 4, and introducing the low-pressure liquid refrigerant in the gas-liquid separator 4 into the refrigerant storage container 5, the gas-liquid separator 4 can be designed to be smaller. The newly added refrigerant storage container 5 can be any shape that is easy to install, such as a pipeline type, thereby reducing the unit size.

[0042] See Figure 2 As shown, the gas-liquid separator 4 is positioned higher than the refrigerant storage container 5, and a first control valve 6 is installed in the flow path between the gas-liquid separator 4 and the refrigerant storage container 5. The first control valve 6 can be a solenoid valve or an electric valve.

[0043] In this embodiment, when the first control valve 6 is turned on, the gas-liquid separator 4 is connected to the refrigerant storage container 5, and the liquid refrigerant in the gas-liquid separator 4 can be automatically transferred into the refrigerant storage container 5 under the action of gravity. When the first control valve 6 is turned off, the connection between the gas-liquid separator 4 and the refrigerant storage container 5 is cut off, thereby achieving controllable connection between the gas-liquid separator 4 and the refrigerant storage container 5. Alternatively, a water pump can be installed between the gas-liquid separator 4 and the refrigerant storage container 5 to achieve controllable connection between them.

[0044] It should be noted that the refrigerant in the gas-liquid separator 4 needs to be transferred to the refrigerant temporary storage container 5. Therefore, an outlet needs to be added to the gas-liquid separator 4. The position of the outlet should be slightly higher than the position of the oil return port 11 on the gas-liquid separator 4. This can prevent the lubricating oil recovered in the gas-liquid separator 4 from being carried into the refrigerant temporary storage container 5.

[0045] See Figure 1 As shown, the air conditioning system also includes a four-way valve 7, which has a first valve port, a second valve port, a third valve port, and a fourth valve port. The first valve port is connected to the compressor 1, the second valve port is connected to the outdoor heat exchanger 2, the third valve port is connected to the indoor heat exchanger 3, and the fourth valve port is connected to the gas-liquid separator 4.

[0046] In this technical solution, by setting a four-way valve 7 in the air conditioning system, refrigerant reversal can be achieved, enabling the air conditioning system to operate in multiple modes such as defrosting, heating, and cooling. When the air conditioning system is operating in defrosting mode, the refrigerant discharged from the compressor 1 enters the four-way valve 7 through the first valve port, then enters the outdoor heat exchanger 2 through the second valve port of the four-way valve 7, then flows through the indoor heat exchanger 3 and re-enters the four-way valve 7 through the third valve port, then enters the gas-liquid separator 4 through the fourth valve port of the four-way valve 7, and finally returns to the compressor 1 to form a cycle. Figure 3 As shown. When the air conditioning system is operating in heating mode, the refrigerant discharged from compressor 1 enters four-way valve 7 through the first valve port, then enters indoor heat exchanger 3 through the third valve port of four-way valve 7, then flows through outdoor heat exchanger 2 and re-enters four-way valve 7 through the second valve port, then enters gas-liquid separator 4 through the fourth valve port of four-way valve 7, and finally returns to compressor 1 to form a cycle, as shown. Figure 5 As shown. When the air conditioning system is operating in cooling mode, the refrigerant discharged from compressor 1 enters four-way valve 7 through the first valve port, then enters outdoor heat exchanger 2 through the second valve port of four-way valve 7, then flows through indoor heat exchanger 3 and re-enters four-way valve 7 through the third valve port, then enters gas-liquid separator 4 through the fourth valve port of four-way valve 7, and finally returns to compressor 1 to form a cycle, as shown. Figure 7 As shown. It is understandable that the refrigerant flow direction is the same when the air conditioning system is in defrost mode and in cooling mode.

[0047] See Figure 1 As shown, the refrigerant storage container 5 is connected to the flow path between the outdoor heat exchanger 2 and the indoor heat exchanger 3 via a second control valve 9. The second control valve 9 can be a solenoid valve or an electric valve.

[0048] In this embodiment, when the air conditioning system operates in heating and defrosting modes during winter, a large amount of liquid refrigerant is temporarily stored in the refrigerant storage container 5. As the air conditioning system operates, the amount of refrigerant circulating in the system may become slightly insufficient. When the refrigerant storage container 5 is connected to the flow path between the outdoor heat exchanger 2 and the indoor heat exchanger 3 via the second control valve 9, if the amount of refrigerant circulating in the system is insufficient, the second control valve 9 can be opened to replenish the refrigerant in the refrigerant storage container 5 into the system circulation loop.

[0049] See Figure 1 As shown, a throttling element 8 is installed in the flow path between the indoor heat exchanger 3 and the outdoor heat exchanger 2. The refrigerant temporary storage container 5 is connected to the flow path between the throttling element 8 and the indoor heat exchanger 3 through a second control valve 9. The throttling element 8 can be an electronic expansion valve.

[0050] In this technical solution, the throttling element 8 is used to throttle the refrigerant flowing between the indoor heat exchanger 3 and the outdoor heat exchanger 2 to improve the heat exchange effect of the indoor heat exchanger 3 and the outdoor heat exchanger 2. Following the flow direction of the refrigerant, the upstream of the throttling element 8 is the high-pressure side, and the downstream of the throttling element 8 is the low-pressure side. When the air conditioning system is in defrost mode, the refrigerant flows from the outdoor heat exchanger 2 to the indoor heat exchanger 3. Therefore, the flow path between the outdoor heat exchanger 2 and the throttling element 8 is the high-pressure side, and the flow path between the indoor heat exchanger 3 and the throttling element 8 is the low-pressure side. The indoor heat exchanger 3 is the evaporator. When the refrigerant storage container 5 is connected to the flow path between the throttling element 8 and the indoor heat exchanger 3 through the second control valve 9, it is equivalent to the refrigerant storage container 5 being connected to the low-pressure side of the air conditioning system through the second control valve 9. If the air conditioning system experiences insufficient refrigerant while operating in defrost mode, the second control valve 9 will open, allowing refrigerant in the refrigerant storage container 5 to replenish the low-pressure line. This makes it easier for the replenished refrigerant to be drawn into the indoor heat exchanger 3 by the suction force of the compressor 1, evaporate, and then return to the compressor 1. The refrigerant flow direction when the air conditioning system is operating in defrost mode and requires refrigerant replenishment is as follows: Figure 4 As shown.

[0051] See Figure 1 As shown, a throttling element 8 is installed in the flow path between the indoor heat exchanger 3 and the outdoor heat exchanger 2. The refrigerant storage container 5 is connected to the flow path between the throttling element 8 and the outdoor heat exchanger 2 via a third control valve 10. The third control valve 10 can be a solenoid valve or an electric valve.

[0052] In this embodiment, as mentioned above, following the refrigerant flow direction, the upstream of the throttling element 8 is the high-pressure side, and the downstream of the throttling element 8 is the low-pressure side. When the air conditioning system is operating in heating mode, the refrigerant flows from the indoor heat exchanger 3 to the outdoor heat exchanger 2. Therefore, the flow path between the indoor heat exchanger 3 and the throttling element 8 is the high-pressure side, and the flow path between the outdoor heat exchanger 2 and the throttling element 8 is the low-pressure side. The outdoor heat exchanger 2 is the evaporator. If the air conditioning system experiences insufficient refrigerant during heating mode, the third control valve 10 is activated, and the refrigerant in the refrigerant storage container 5 is replenished into the low-pressure pipeline. This makes it easier for the replenished refrigerant to be drawn into the indoor heat exchanger 3 under the suction of the compressor 1, evaporate, and then return to the compressor 1. The refrigerant flow direction when the air conditioning system is operating in heating mode and needs refrigerant replenishment is as follows: Figure 6 As shown.

[0053] Understandably, the outlet of the refrigerant storage container 5 should ideally be downward-facing and positioned higher than the flow paths on both sides of the throttling element 8. This would allow the refrigerant in the refrigerant storage container 5 to be more easily replenished into the system piping under the influence of pressure differential.

[0054] The present invention also provides a control method for controlling the operation of the aforementioned air conditioning system, the control method comprising:

[0055] The outdoor temperature is recorded as t1;

[0056] Based on t1 and t a The size relationship controls the opening and closing of the first control valve 6;

[0057] Among them, t a Set the first temperature value.

[0058] In this technical solution, the first temperature setpoint t a The outdoor temperature is -7℃, and the outdoor temperature is used as the boundary to determine whether the outdoor heat exchanger 2 is frosted. Once the outdoor heat exchanger 2 is frosted, defrosting is required. During defrosting, the air conditioning system needs to temporarily store most of the refrigerant in the gas-liquid separator 4 in the refrigerant storage container 5. Therefore, the opening and closing of the first control valve 6 can be based on t1 and t2. a The size relationship is determined. Specifically, the outdoor temperature can be obtained by installing a temperature sensor on the outdoor unit of the air conditioning system.

[0059] As a specific implementation method, when t1 < t a At that time, the first control valve 6 is turned on.

[0060] In this embodiment, when the outdoor temperature t1 is below -7°C, the refrigerant flow rate participating in the circulation in the air conditioning system is relatively small, and the outdoor heat exchanger 2 will inevitably frost over. After frost formation, the air conditioning system needs to run in defrost mode to defrost. Therefore, when t1 < ta At this time, the first control valve 6 is turned on, so that most of the liquid refrigerant in the gas-liquid separator 4 is temporarily stored in the refrigerant storage container 5 to shorten the subsequent defrosting time.

[0061] Furthermore, the temperature of outdoor heat exchanger 2 is obtained and denoted as t2. When t a ≤t1≤t b And t2 < t1 - t c At that time, the first control valve 6 is turned on; where t b For the second temperature setpoint, t a <t b , t c Set the third temperature value.

[0062] In this technical solution, the second temperature setpoint t b The third temperature setpoint is 5℃. c The refrigerant flow rate is moderate when the outdoor temperature t1 is between -7℃ and 5℃. The air conditioning system is prone to frosting within this range, and the higher the humidity, the faster the frost layer thickens, and the refrigerant flow rate gradually decreases. A temperature sensor is installed on the outdoor heat exchanger 2 to obtain its own temperature t2. When the outdoor heat exchanger 2 begins to frost, t2 will decrease significantly. When the outdoor heat exchanger 2's own temperature t2 deviates downwards by 6℃ to 10℃ relative to the outdoor temperature t1, it can be determined that the outdoor heat exchanger 2 has begun to frost. Therefore, the first control valve 6 is opened, allowing excess liquid refrigerant in the gas-liquid separator 4 to flow into the refrigerant storage container 5.

[0063] Furthermore, when t2 < t1 - t c -t d At that time, the first control valve 6 is shut off, and the air conditioning system operates in defrost mode; among which, t d Set the fourth temperature value.

[0064] In this embodiment, the fourth temperature setting is 4–8°C. When the detected temperature of the outdoor heat exchanger 2 is t2 < t1 - t2, the temperature is determined. c -t d When the temperature t2 of the outdoor heat exchanger 2 deviates too much downward relative to the outdoor temperature t1, the frost layer on the outdoor heat exchanger 2 is already very thick, and the air conditioning system needs to run in defrost mode to defrost. At this time, the first control valve 6 is cut off, and most of the liquid refrigerant in the gas-liquid separator 4 is temporarily stored in the refrigerant storage container 5. In this way, the refrigerant in the circulation loop does not need to heat the liquid refrigerant in the gas-liquid separator 4, which can quickly increase the suction and discharge temperatures of the compressor 1, so that the temperature entering the outdoor heat exchanger 2 also increases faster, which is more conducive to rapid defrosting.

[0065] As a specific implementation method, when t1 > tb At that time, the first control valve 6 is shut off.

[0066] In this technical solution, when the outdoor temperature t1 is higher than 5℃, the refrigerant flow rate participating in the system circulation is large and the unit basically does not frost. Therefore, there is less liquid refrigerant in the gas-liquid separator 4, and the refrigerant mainly flows in the system pipelines and does not need to be stored in the refrigerant temporary storage container 5. So at this time, the first control valve 6 is shut off. It can be understood that when the air conditioning system needs to be shut down, if the first control valve 6 is in the open state, it is necessary to shut off the first control valve 6 first before shutting down the system.

[0067] As a specific implementation method, when the air conditioning system is in defrost mode, the air conditioning system also includes a throttling element 8 and a second control valve 9. When the opening degree of the throttling element 8 is greater than the first set opening degree, the second control valve 9 is controlled to be turned on and then turned off after a first set time.

[0068] In this embodiment, the first set opening degree is 80% of the maximum opening degree of the throttling element 8, and the first set time is 8-10 seconds. When the amount of refrigerant participating in the circulation in the air conditioning system is small, the opening degree of the throttling element 8 is generally large. When the air conditioning system is running in defrost mode, if the opening degree of the throttling element 8 is detected to be greater than 80% of the maximum opening degree, it indicates that the amount of refrigerant participating in the circulation in the system is small, and the refrigerant storage container 5 needs to replenish the refrigerant in the circulation loop. Therefore, the second control valve 9 is controlled to open, so that the refrigerant in the refrigerant storage container 5 is replenished into the low-pressure pipeline of the circulation loop. This not only achieves the replenishment of refrigerant in the circulation loop, but also the replenished refrigerant is easily drawn into the evaporator by the suction of the compressor 1 and evaporated before returning to the compressor 1. Experiments have shown that a replenishment time of 8-10 seconds is better, so that the refrigerant replenished in one time can be completely evaporated in the evaporator. Therefore, the second control valve 9 should be cut off again after being opened for 8-10 seconds. It should be noted that when the air conditioning system is in defrost mode, the first control valve 6 is in the cut-off state, and the liquid refrigerant in the gas-liquid separator 4 will not flow into the refrigerant storage container 5.

[0069] Furthermore, after the second set time period, the opening of the throttling element 8 continues to increase, controlling the second control valve 9 to open and then controlling the second control valve 9 to close after the first set time period.

[0070] In this technical solution, the second set duration is 30 seconds. After the second control valve 9 is turned on for 8 to 10 seconds to replenish the refrigerant in the refrigerant storage container 5 into the circulation loop, if after 30 seconds the opening of the throttling element 8 is detected to be larger than before the last replenishment, it indicates that the amount of refrigerant replenished last time was insufficient and the amount of refrigerant participating in the circulation in the system is still too small. In this case, it is necessary to control the second control valve 9 to be turned on for 8 to 10 seconds to replenish the refrigerant in the system again, and this cycle is repeated until the opening of the throttling element 8 no longer increases.

[0071] As a specific implementation method, when the air conditioning system is running in heating mode, the air conditioning system also includes a throttling element 8 and a third control valve 10. When the opening degree of the throttling element 8 is greater than the second set opening degree, the first control valve 6 is controlled to be cut off, the third control valve 10 is controlled to be turned on, and after a third set time period, the third control valve 10 is controlled to be cut off.

[0072] In this embodiment, the second set opening degree is 80% of the maximum opening degree of the throttling element 8, and the third set degree is 5-10 seconds. When the amount of refrigerant participating in the circulation in the air conditioning system is large, the opening degree of the throttling element 8 is generally small; when the amount of refrigerant participating in the circulation in the air conditioning system is small, the opening degree of the throttling element 8 is generally large. When the air conditioning system is running in heating mode, if the opening degree of the throttling element 8 is detected to be greater than 80% of the maximum opening degree, it indicates that the amount of refrigerant participating in the circulation in the system is small, and the refrigerant storage container 5 needs to replenish the refrigerant in the circulation loop. Therefore, the first control valve 6 is controlled to be cut off, and the third control valve 10 is controlled to be opened, so that the refrigerant in the refrigerant storage container 5 is replenished into the low-pressure pipeline of the circulation loop. This not only achieves the replenishment of refrigerant in the circulation loop, but also the replenished refrigerant is easily drawn into the evaporator by the suction of the compressor 1 to evaporate and then return to the compressor 1. Experiments have shown that a replenishment time of 5 to 10 seconds is better, as it allows the refrigerant to evaporate completely in the evaporator. Therefore, the third control valve 10 should be shut off again after being open for 8 to 10 seconds.

[0073] Furthermore, after the fourth set time period, the opening of the throttling element 8 continues to increase, controlling the third control valve 10 to open and then controlling the third control valve 10 to close after the third set time period.

[0074] In this embodiment, the fourth set duration is two minutes. After the second control valve 9 is opened for 5-10 seconds to replenish the refrigerant in the refrigerant storage container 5 into the circulation loop, if after two minutes the opening of the throttling element 8 is detected to be larger than before the last replenishment, it indicates that the amount of refrigerant replenished last time was insufficient, and the amount of refrigerant participating in the circulation in the system is still too small. In this case, the third control valve 10 needs to be opened for 5-10 seconds to replenish the refrigerant in the system again, and this cycle is repeated until the opening of the throttling element 8 no longer increases. This measure can meet the demand for increased refrigerant flow when the ambient temperature changes from low to high during continuous operation of the air conditioning system.

[0075] It should be noted that because the defrosting time is shorter, the control valve in defrosting mode operates for a longer period of time compared to heating mode, while the interval between refrigerant replenishments is shorter. In other words, when the air conditioning system is in defrosting mode, the amount of refrigerant replenished at one time is larger, and the interval between replenishments is shorter, which also helps to shorten the defrosting time.

[0076] It will be readily understood by those skilled in the art that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0077] The above are merely 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 should be included within the protection scope of the present invention. The above are merely preferred embodiments of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. An air conditioning system, characterized by, The air conditioning system comprises a compressor (1), an outdoor heat exchanger (2), an indoor heat exchanger (3), a gas-liquid separator (4) and a refrigerant temporary storage container (5), the compressor (1), the outdoor heat exchanger (2), the indoor heat exchanger (3) and the gas-liquid separator (4) form a refrigerant circulation loop, the refrigerant temporary storage container (5) is in controllable communication with the gas-liquid separator (4), and a throttling element (8) is arranged on a flow path between the indoor heat exchanger (3) and the outdoor heat exchanger (2); The refrigerant temporary storage container (5) is connected to the flow path between the throttling element (8) and the indoor heat exchanger (3) through a second control valve (9); and / or the refrigerant temporary storage container (5) is connected to the flow path between the throttling element (8) and the outdoor heat exchanger (2) through a third control valve (10).

2. The air conditioning system of claim 1, wherein, The position of the gas-liquid separator (4) is higher than that of the refrigerant temporary storage container (5), and a first control valve (6) is arranged on a flow path between the gas-liquid separator (4) and the refrigerant temporary storage container (5).

3. The air conditioning system of claim 1, wherein, Further comprising a four-way valve (7) having a first valve port, a second valve port, a third valve port and a fourth valve port, the first valve port being connected to the compressor (1), the second valve port being connected to the outdoor heat exchanger (2), the third valve port being connected to the indoor heat exchanger (3), and the fourth valve port being connected to the gas-liquid separator (4).

4. A control method of an air conditioning system, characterized by, A control method for controlling the operation of the air conditioning system of any one of claims 1 to 3, the position of the gas-liquid separator (4) being higher than that of the refrigerant temporary storage container (5), a first control valve (6) being arranged on a flow path between the gas-liquid separator (4) and the refrigerant temporary storage container (5), the control method comprising: Obtaining an outdoor temperature as t1; According to the size relation of t1 and t a , the on-off of the first control valve (6) is controlled; wherein t a is a first temperature setpoint.

5. The control method according to claim 4, characterized by When t1 a the first control valve (6) is controlled to be on.

6. The control method according to claim 4, characterized by Acquire the temperature of the outdoor heat exchanger (2) as t2, when t a ≤t1≤t b , and t2 c t1-t b , control the first control valve (6) to be on; wherein t a is the second temperature set value, t b t c is the third temperature set value.

7. The control method according to claim 6, characterized by When t2 < t1 - t c -t d When the first control valve (6) is shut off, the air conditioning system is controlled to operate in defrost mode; wherein, t d Set the fourth temperature value.

8. The control method according to claim 5 or 6, characterized by, When the air conditioning system operates in a defrosting mode, the refrigerant temporary storage container (5) is connected to the flow path between the throttling element (8) and the indoor heat exchanger (3) through a second control valve (9), and the opening degree of the throttling element (8) is greater than a first set opening degree, the second control valve (9) is controlled to be turned on and then controlled to be cut off after a first set time period.

9. The control method according to claim 8, characterized by, When the opening degree of the throttling element (8) continues to increase after a second set time period, the second control valve (9) is controlled to be turned on and then controlled to be cut off after the first set time period.

10. The control method according to claim 5 or 6, characterized by, When the air conditioning system operates in a heating mode, the refrigerant temporary storage container (5) is connected to the flow path between the throttling element (8) and the outdoor heat exchanger (2) through the third control valve (10), and the opening degree of the throttling element (8) is greater than a second set opening degree, the first control valve (6) is controlled to be cut off, the third control valve (10) is controlled to be turned on and then controlled to be cut off after a third set time period.

11. The control method according to claim 10, characterized by, When the opening degree of the throttling element (8) continues to increase after a fourth set time period, the third control valve (10) is controlled to be turned on and then controlled to be cut off after the third set time period.

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