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 compressor, an outdoor heat exchanger, an indoor heat exchanger, a gas-liquid separator and a refrigerant temporary storage container, the compressor, the outdoor heat exchanger, the indoor heat exchanger and the gas-liquid separator form a refrigerant circulation loop, and the refrigerant temporary storage container is controllably communicated with the gas-liquid separator. According to the air conditioning system, the refrigerant temporary storage container is additionally arranged in the air conditioning system and is controllably communicated with the gas-liquid separator, so that when the liquid refrigerant in the gas-liquid separator is more, the refrigerant temporary storage container can be communicated with the gas-liquid separator; and then most of the liquid refrigerant in the gas-liquid separator is transferred and stored in the refrigerant temporary storage container. In this way, when the outdoor heat exchanger is defrosted, the liquid refrigerant in the gas-liquid separator does not need to be heated, so that the suction and exhaust temperature of the compressor can be increased, the temperature of the refrigerant entering the outdoor heat exchanger can be guaranteed, and finally the defrosting time can be shortened.

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] Air-cooled central air-conditioning units are widely used, such as multi-split units, duct units, household units, modular units, etc. The outdoor units of such central air-conditioning units all use finned heat exchangers, which are prone to frost when the air-conditioning unit is heating in winter. The more frost there is, the less the flow of refrigerant involved in the cycle in the unit. All the excess refrigerant is stored in the vapor-liquid separator in liquid form. The unit is usually defrosted by allowing the high-temperature and high-pressure refrigerant discharged from the compressor to flow back into the finned heat exchanger, and the low-temperature liquid refrigerant in the vapor-liquid separator must be heated and evaporated during defrosting. However, this will reduce the suction and exhaust temperatures of the compressor, and the temperature of the refrigerant entering the finned heat exchanger will also decrease, delaying the defrosting time of the unit. Summary of the invention

[0003] Therefore, the present invention provides an air-conditioning system which can solve the technical problem that when the air-conditioning unit is defrosted, in addition to allowing the high-temperature and high-pressure refrigerant discharged from the compressor to flow back into the fin-type heat exchanger, the low-temperature liquid refrigerant in the vapor-liquid separator must be completely heated and evaporated. However, this will reduce the suction temperature and exhaust temperature of the compressor, and also reduce the temperature of the refrigerant entering the fin-type heat exchanger, thereby delaying the defrosting time of the unit.

[0004] In order to solve the above problems, the present invention provides an air-conditioning system, including a compressor, an outdoor heat exchanger, an indoor heat exchanger, a gas-liquid separator and a refrigerant temporary storage container, wherein the compressor, the outdoor heat exchanger, the indoor heat exchanger and the gas-liquid separator form a refrigerant circulation loop, and the refrigerant temporary storage container is controllably connected to the gas-liquid separator.

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

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

[0007] In some embodiments, a throttling element is provided on 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 indoor heat exchanger through a second control valve.

[0008] In some embodiments, a throttling element is provided on 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 through 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] Get the outdoor temperature and record it as t1;

[0011] According to t1 and t a , controlling the on-off of the first control valve;

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

[0013] In some embodiments, when t1<t a When the first control valve is controlled to be turned on.

[0014] In some embodiments, the temperature of the outdoor heat exchanger is obtained as t2. a ≤t1≤t b , and t2<t1-t c When t b is the second temperature setting value, t a <t b , t c is the third temperature setting value.

[0015] In some embodiments, when t2<t1-t c -t d When t d It is the fourth temperature setting value.

[0016] In some embodiments, when the air-conditioning system operates in a defrost mode, the air-conditioning system further includes a throttling element and a second control valve, and when the opening of the throttling element is greater than a first set opening, the second control valve is controlled to be turned on and the second control valve is controlled to be turned off after a first set time.

[0017] In some embodiments, when the opening of the throttling element continues to increase after the second set time has passed, the second control valve is controlled to be turned on, and after the first set time has passed, the second control valve is controlled to be turned off.

[0018] In some embodiments, when the air-conditioning system operates in a heating mode, the air-conditioning system further includes a throttling element and a third control valve, and when the opening of the throttling element is greater than a second set opening, the first control valve is controlled to be cut off, the third control valve is controlled to be turned on, and the third control valve is controlled to be cut off after a third set time period.

[0019] In some embodiments, when the opening of the throttling element continues to increase after a fourth set time, the third control valve is controlled to be turned on, and after the third set time, the third control valve is controlled to be turned off.

[0020] The present invention provides an air conditioning system and a control method thereof, which have the following beneficial effects:

[0021] Since the refrigerant temporary storage container is added to the air conditioning system of the present application, and the refrigerant temporary storage container is controllably connected to the gas-liquid separator, when there is a lot of liquid refrigerant in the gas-liquid separator, the refrigerant temporary 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 temporary storage container. In this way, when the outdoor heat exchanger is defrosted, it is not necessary to heat the liquid refrigerant in the gas-liquid separator, so that the suction and exhaust temperature of the compressor can be increased, and then the refrigerant temperature entering the outdoor heat exchanger can be guaranteed, which ultimately helps to shorten the defrosting time of the unit.

[0022] At the same time, when the air conditioning system is running at low temperatures in winter, the lower the ambient temperature, the smaller the flow rate of the refrigerant involved in the cycle, and the more liquid refrigerant is stored in the gas-liquid separator. In the case of low ambient temperature, when the unit is shut down and restarted, the high and low pressure difference of the unit is small in a short period of time, which is not enough to promote the flow of refrigerant. At this time, the compressor will draw the liquid refrigerant into the compressor through the oil return port on the gas-liquid separator, which makes the compressor have a certain risk of liquid hammer. By setting up a refrigerant temporary storage container, the liquid refrigerant can be transferred to the refrigerant temporary storage container, so that when the compressor is turned on, the liquid refrigerant can be prevented from being drawn into the compressor, thereby avoiding liquid hammer.

[0023] Furthermore, by adding a refrigerant temporary storage container that is controllably connected to the gas-liquid separator and introducing the low-pressure liquid refrigerant in the gas-liquid separator into the refrigerant temporary storage container, the gas-liquid separator can be designed to be smaller, and the newly added refrigerant temporary storage container can be any shape that is convenient for installation, such as a pipeline type, thereby also reducing the size of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] 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.

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

[0026] Figure 2 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 A schematic diagram of the refrigerant flow direction when the air-conditioning system according to an embodiment of the present invention operates in a defrost mode;

[0028] Figure 4 A schematic diagram of the refrigerant flow direction when the air-conditioning system according to an embodiment of the present invention operates in a defrost mode and the refrigerant temporary storage container replenishes refrigerant into the system;

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

[0030] Figure 6 A schematic diagram of the refrigerant flow direction when the air-conditioning system according to an embodiment of the present invention operates in a heating mode and the refrigerant temporary storage container replenishes refrigerant into the system;

[0031] Figure 7 Schematic diagram of the refrigerant flow when the air-conditioning system according to an embodiment of the present invention operates in a cooling mode.

[0032] The reference numerals are as follows:

[0033] 1. Compressor; 2. Outdoor heat exchanger; 3. Indoor heat exchanger; 4. Gas-liquid separator; 5. Refrigerant temporary 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 DESCRIPTION

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[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 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, and the refrigerant temporary storage container 5 is controllably connected to the gas-liquid separator 4.

[0039] In this technical solution, since the refrigerant temporary storage container 5 is added to the air conditioning system of the present application, and the refrigerant temporary storage container 5 is controllably connected to the gas-liquid separator 4, when there is a lot of liquid refrigerant in the gas-liquid separator 4, the refrigerant temporary 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 is transferred to the refrigerant temporary storage container 5. In this way, when the outdoor heat exchanger 2 is defrosted, it is not necessary to heat the liquid refrigerant in the gas-liquid separator 4, so that the suction and exhaust temperature of the compressor 1 can be increased, and then the temperature of the refrigerant entering the outdoor heat exchanger 2 can be guaranteed, which ultimately helps to shorten the defrosting time of the unit. Among them, the outdoor heat exchanger 2 is a finned heat exchanger.

[0040] At the same time, when the air conditioning system is running at low temperatures in winter, the lower the ambient temperature, the smaller the flow rate of the refrigerant involved in the cycle, and the more liquid refrigerant is stored in the gas-liquid separator 4. When the ambient temperature is low, when the unit is shut down and restarted, the high and low pressure difference of the unit is small in a short period of time, which is not enough to promote the flow of refrigerant. At this time, the compressor will draw the liquid refrigerant into the compressor 1 through the oil return port 11 on the gas-liquid separator 4, which makes the compressor 1 have a certain risk of liquid hammer. By setting up a refrigerant temporary storage container 5, the liquid refrigerant can be transferred to the refrigerant temporary storage container 5, so that when the compressor 1 is turned on, the liquid refrigerant can be prevented from being drawn into the compressor 1, thereby avoiding liquid hammer.

[0041] Furthermore, by adding a refrigerant temporary storage container 5 which 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 temporary storage container 5, the gas-liquid separator 4 can be designed to be smaller, and the newly added refrigerant temporary storage container 5 can be any shape that is convenient for installation, such as a pipeline type, thereby reducing the size of the unit.

[0042] See also Figure 2 As shown, 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 provided on the flow path between the gas-liquid separator 4 and the refrigerant temporary storage container 5. The first control valve 6 may 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 temporary storage container 5, and the liquid refrigerant in the gas-liquid separator 4 can be automatically transferred into the refrigerant temporary storage container 5 under the action of gravity; when the first control valve 6 is cut off, the connection between the gas-liquid separator 4 and the refrigerant temporary storage container 5 can be cut off, thereby achieving controllable connection between the gas-liquid separator 4 and the refrigerant temporary storage container 5. In addition, a water pump can also be provided between the gas-liquid separator 4 and the refrigerant temporary storage container 5, and the controllable connection between the gas-liquid separator 4 and the refrigerant temporary storage container 5 can be achieved through the water pump.

[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, and a liquid outlet needs to be added to the gas-liquid separator 4, and the position of the liquid outlet needs to be slightly higher than the position of the oil return port 11 on the gas-liquid separator 4, so as to prevent the lubricating oil recovered in the gas-liquid separator 4 from being brought into the refrigerant temporary storage container 5.

[0045] See also 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, so that the air-conditioning system can operate in multiple modes such as defrosting, heating, and cooling. When the air-conditioning system operates in defrosting mode, the refrigerant discharged from the compressor 1 enters the four-way valve 7 from the first valve port, and then enters the outdoor heat exchanger 2 from the second valve port of the four-way valve 7, then flows through the indoor heat exchanger 3 and enters the four-way valve 7 again from the third valve port, and then enters the gas-liquid separator 4 from the fourth valve port of the four-way valve 7, and finally returns to the compressor 1 to form a cycle. Figure 3 When the air conditioning system is in heating mode, the refrigerant discharged from the compressor 1 enters the four-way valve 7 from the first valve port, then enters the indoor heat exchanger 3 from the third valve port of the four-way valve 7, then flows through the outdoor heat exchanger 2 and enters the four-way valve 7 again from the second valve port, then enters the gas-liquid separator 4 from the fourth valve port of the four-way valve 7, and finally returns to the compressor 1 to form a cycle, as shown in FIG. Figure 5 When the air conditioning system is in cooling mode, the refrigerant discharged from the compressor 1 enters the four-way valve 7 from the first valve port, then enters the outdoor heat exchanger 2 from the second valve port of the four-way valve 7, then flows through the indoor heat exchanger 3 and enters the four-way valve 7 again from the third valve port, then enters the gas-liquid separator 4 from the fourth valve port of the four-way valve 7, and finally returns to the compressor 1 to form a cycle, as shown in FIG. Figure 7 It can be understood that the refrigerant flow direction is the same when the air conditioning system is running in defrost mode and cooling mode.

[0047] See also Figure 1 As shown, the refrigerant temporary storage container 5 is connected to the flow path between the outdoor heat exchanger 2 and the indoor heat exchanger 3 through the 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 is operated in the heating mode and the defrosting mode in winter, a large amount of liquid refrigerant will be temporarily stored in the refrigerant temporary storage container 5, and as the air conditioning system is operated, the amount of refrigerant circulating in the system will be slightly insufficient. When the refrigerant temporary storage container 5 is connected to the flow path between the outdoor heat exchanger 2 and the indoor heat exchanger 3 through the second control valve 9, if the amount of refrigerant circulating in the system is insufficient, the refrigerant in the refrigerant temporary storage container 5 can be supplemented to the system circulation loop by controlling the second control valve 9 to be turned on.

[0049] See also Figure 1 As shown, a throttling element 8 is provided on the flow path between the indoor heat exchanger 3 and the outdoor heat exchanger 2, and 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 may 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 defrosting 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 an evaporator. When the refrigerant temporary 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 temporary 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 is running in defrost mode and the refrigerant is insufficient, the second control valve 9 is turned on, and the refrigerant in the refrigerant temporary storage container 5 will be replenished into the low-pressure pipeline, so that it is easier to draw the replenished refrigerant into the indoor heat exchanger 3 under the suction of the compressor 1 to evaporate and then return to the compressor 1. The refrigerant flow direction when the air conditioning system is running in defrost mode and needs to replenish refrigerant is as follows Figure 4 shown.

[0051] See also Figure 1 As shown, a throttling element 8 is provided on the flow path between the indoor heat exchanger 3 and the outdoor heat exchanger 2, and 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. The third control valve 10 may be a solenoid valve or an electric valve.

[0052] In the present embodiment, it has been mentioned above that along 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 operating in the 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 an evaporator. If the air-conditioning system is running in the heating mode and the amount of refrigerant is insufficient, the third control valve 10 is turned on, and the refrigerant in the refrigerant temporary storage container 5 will be supplemented to the low-pressure pipeline. This makes it easier for the supplementary refrigerant to be drawn into the indoor heat exchanger 3 under the suction of the compressor 1 to evaporate and then return to the compressor 1. The refrigerant flow direction when the air-conditioning system is running in the heating mode and needs to supplement the refrigerant is as follows: Figure 6 shown.

[0053] It is understandable that the outlet of the refrigerant temporary storage container 5 is preferably downward, and the outlet position is higher than the flow path on both sides of the throttling element 8, so that the refrigerant in the refrigerant temporary storage container 5 can be more easily added to the system pipeline under the action of pressure difference.

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

[0055] Get the outdoor temperature and record it as t1;

[0056] According to t1 and t a The size relationship controls the on-off of the first control valve 6;

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

[0058] In this technical solution, the first temperature setting value t a The outdoor temperature is -7℃, and the outdoor temperature is -7℃ as the limit to determine whether the outdoor heat exchanger 2 is frosted. When the outdoor heat exchanger 2 is frosted, it needs to be defrosted. When the air conditioning system is defrosted, most of the refrigerant in the gas-liquid separator 4 needs to be temporarily stored in the refrigerant temporary storage container 5. Therefore, the on-off of the first control valve 6 can be determined according to t1 and t a The acquisition of the outdoor temperature can be achieved by setting a temperature sensing package in the outdoor unit of the air-conditioning system.

[0059] As a specific implementation method, when t1<t a When , the first control valve 6 is controlled to be turned on.

[0060] In this embodiment, when the outdoor temperature t1 is lower than -7°C, the refrigerant flow rate in the air-conditioning system is small, and the outdoor heat exchanger 2 is bound to be frosted. After frosting, the air-conditioning system needs to run the defrost mode for defrosting. Therefore, when t1<ta When the first control valve 6 is controlled to be turned on, most of the liquid refrigerant in the gas-liquid separator 4 is temporarily stored in the refrigerant temporary storage container 5 to shorten the subsequent defrosting time.

[0061] Further, the temperature of outdoor heat exchanger 2 is obtained as t2. a ≤t1≤t b , and t2<t1-t c When t b is the second temperature setting value, t a <t b , t c is the third temperature setting value.

[0062] In this technical solution, the second temperature setting value t b The third temperature setting value is 5℃. c 6~10℃. When the outdoor temperature t1 is in the range of -7℃ to 5℃, the refrigerant flow is moderate. The air conditioning system is very easy to frost when operating in this range. The higher the humidity, the faster the frost layer thickens, and the refrigerant flow gradually decreases. A temperature sensing package is set on the outdoor heat exchanger 2 to obtain the self-temperature t2 of the outdoor heat exchanger 2. When the outdoor heat exchanger 2 begins to frost, t2 will be significantly reduced. When the self-temperature t2 of the outdoor heat exchanger 2 deviates downward by 6℃~10℃ relative to the outdoor temperature t1, it can be determined that the outdoor heat exchanger 2 begins to frost. Therefore, the first control valve 6 is controlled to be turned on, so that the excess liquid refrigerant in the gas-liquid separator 4 flows into the refrigerant temporary storage container 5.

[0063] Furthermore, when t2<t1-t c -t d When t d It is the fourth temperature setting value.

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

[0065] As a specific implementation method, when t1>tb When , the first control valve 6 is controlled to be cut off.

[0066] In this technical solution, when the outdoor temperature t1 is higher than 5°C, the refrigerant flow rate involved in the circulation in the system is large and the unit will basically not frost, so there is less liquid refrigerant in the gas-liquid separator 4, and the refrigerant basically circulates in the system pipeline and does not need to be stored in the refrigerant temporary storage container 5, so the first control valve 6 is controlled to be cut off at this time. It can be understood that when the air-conditioning system needs to be shut down, if the first control valve 6 is in the conducting state, it is necessary to control the first control valve 6 to be cut off first, and then shut down.

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

[0068] In this embodiment, the first setting opening is 80% of the maximum opening of the throttling element 8, and the first setting is 8 to 10 seconds. When the amount of refrigerant participating in the circulation in the air-conditioning system is small, the opening of the throttling element 8 is generally large. When the air-conditioning system is running in defrosting mode, if it is detected that the opening of the flow element 8 is greater than 80% of the maximum opening, it indicates that the amount of refrigerant participating in the circulation in the system is small, and the refrigerant temporary storage container 5 is required to replenish the refrigerant in the circulation loop. Therefore, the second control valve 9 is controlled to be turned on, so that the refrigerant in the refrigerant temporary storage container 5 is replenished into the low-pressure pipeline of the circulation loop, so that not only can the refrigerant be replenished in the circulation loop, but also the replenished refrigerant is easily drawn into the evaporator under the suction of the compressor 1 to evaporate and then return to the compressor 1. It has been experimentally demonstrated that the replenishment time is preferably 8 to 10 seconds, which can make the refrigerant replenished once completely evaporate in the evaporator, so the second control valve 9 needs to be cut off again after being turned on for 8 to 10 seconds. It should be noted that when the air-conditioning system is running in the 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 temporary storage container 5 .

[0069] Further, when the opening of the throttling element 8 continues to increase after the second set time, the second control valve 9 is controlled to be turned on, and after the first set time, the second control valve 9 is controlled to be turned off.

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

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

[0072] In this embodiment, the second setting opening is 80% of the maximum opening of the throttling element 8, and the third setting is 5 to 10 seconds. When the amount of refrigerant participating in the circulation in the air-conditioning system is large, the opening 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 of the throttling element 8 is generally large. When the air-conditioning system is running in the heating mode, if it is detected that the opening of the flow element 8 is greater than 80% of the maximum opening, it indicates that the amount of refrigerant participating in the circulation in the system is small, and the refrigerant temporary storage container 5 is required 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 turned on, so that the refrigerant in the refrigerant temporary storage container 5 is replenished into the low-pressure pipeline of the circulation loop, so that not only can the refrigerant be replenished in the circulation loop, but the replenished refrigerant is also easily drawn into the evaporator under the suction of the compressor 1 to evaporate and then return to the compressor 1. According to experimental demonstration, the best replenishment time is 5 to 10 seconds, which can make the refrigerant replenished once completely evaporate in the evaporator. Therefore, the third control valve 10 needs to be cut off again after being turned on for 8 to 10 seconds.

[0073] Further, when the opening of the throttling element 8 continues to increase after the fourth set time, the third control valve 10 is controlled to be turned on, and after the third set time, the third control valve 10 is controlled to be turned off.

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

[0075] It should be noted that due to the shorter defrosting time, the control valve is on for a longer time and the refilling interval is shorter when the air conditioning system is in defrosting mode than when it is in heating mode. That is, when the air conditioning system is in defrosting mode, the amount of refrigerant replenished at a time is larger and the refilling interval is shorter, which also helps to shorten the defrosting time.

[0076] 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.

[0077] 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), 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 controllably connected to the gas-liquid separator (4).

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

3. The air conditioning system according to claim 1, characterized in that: It also includes a four-way valve (7), the 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. The air conditioning system according to any one of claims 1 to 3, characterized in that: A throttling element (8) is provided on the flow path between the indoor heat exchanger (3) and the outdoor heat exchanger (2), and the refrigerant temporary storage container (5) is connected to the flow path between the throttling element (8) and the indoor heat exchanger (3) via a second control valve (9).

5. The air conditioning system according to any one of claims 1 to 3, characterized in that: A throttling element (8) is provided on the flow path between the indoor heat exchanger (3) and the outdoor heat exchanger (2), and the refrigerant temporary 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).

6. A control method for an air conditioning system, characterized in that: Used to control the operation of the air conditioning system according to any one of claims 2 to 5, the control method comprises: Get the outdoor temperature and record it as t1; According to t1 and t a to control the on-off of the first control valve (6); Among them, t a is the first temperature setting value.

7. The control method according to claim 6, characterized in that: When t1<t a When the first control valve (6) is controlled to be turned on.

8. The control method according to claim 6, characterized in that: The temperature of the outdoor heat exchanger (2) is recorded as t2. a ≤t1≤t b , and t2<t1-t c When the first control valve (6) is controlled to be turned on; wherein, t b is the second temperature setting value, t a <t b , t c is the third temperature setting value.

9. The control method according to claim 8, characterized in that: When t2<t1-t c -t d When t d It is the fourth temperature setting value.

10. The control method according to claim 7 or 8, characterized in that: When the air conditioning system operates in a defrost mode, the air conditioning system further comprises a throttling element (8) and a second control valve (9), and when the opening of the throttling element (8) is greater than a first set opening, the second control valve (9) is controlled to be turned on and after a first set time has passed, the second control valve (9) is controlled to be turned off.

11. The control method according to claim 10, characterized in that: When the opening of the throttling element (8) continues to increase after the second set time, the second control valve (9) is controlled to be turned on, and after the first set time, the second control valve (9) is controlled to be turned off.

12. The control method according to claim 7 or 8, characterized in that: When the air conditioning system operates in a heating mode, the air conditioning system further comprises a throttling element (8) and a third control valve (10), and when 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 the third control valve (10) is controlled to be cut off after a third set time period.

13. The control method according to claim 12, characterized in that: When the opening of the throttling element (8) continues to increase after a fourth set time, the third control valve (10) is controlled to be turned on, and after the third set time, the third control valve (10) is controlled to be turned off.

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