Air conditioning system and control method

Abstract

The invention provides an air conditioning system and a control method. The air conditioning system comprises a compressor and a gas-liquid separator. The heat exchange structure is provided with a first heat exchange channel and a second heat exchange channel which are used for heat exchange, an inlet of the first heat exchange channel selectively communicates with or is disconnected from an exhaust port of the compressor, and an outlet of the first heat exchange channel communicates with an inlet of the gas-liquid separator; an inlet of the second heat exchange channel selectively communicates with or is disconnected from the bottom of the gas-liquid separator, an outlet of the second heat exchange channel communicates with an air inlet of the compressor, and the first heat exchange channel is used for heating the second heat exchange channel. According to the technical scheme, the technical problem that in the prior art, a compressor of an air conditioning system is prone to liquid impact can be solved.

Description

Technical Field

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

[0002] At present, the compressor of the air-conditioning system is easily damaged by liquid hammer, so most air-conditioning systems are equipped with a gas-liquid separator to separate the liquid refrigerant from the gaseous refrigerant to avoid the liquid refrigerant entering the compressor and causing liquid hammer.

[0003] However, the separation efficiency of traditional gas-liquid separators is low, especially at low temperatures, which will make the separation efficiency even lower. In order to reduce the cost of air-conditioning systems and improve the reliability of air-conditioning systems, the volume of general gas-liquid separators is relatively limited, which further exacerbates the risk of liquid return. In particular, when the air-conditioning system is operating in a super-low temperature outdoor environment for heating, a large amount of liquid refrigerant accumulates in the gas-liquid separator. Due to the low ambient temperature, the refrigerant in the air-conditioning system is difficult to circulate in a short period of time, resulting in a low exhaust superheat of the air-conditioning system for a long period of time after the compressor is started. At this time, not only is liquid hammer prone to occur, but it will also cause poor lubrication of the lubricating oil and cause damage to the compressor. In addition, when the air-conditioning system is operating in a long-term heating mode, the outdoor heat exchanger will continue to frost, which will further aggravate the accumulation of liquid refrigerant in the vapor separation, resulting in a large amount of liquid return causing impact on the compressor. Summary of the invention

[0004] The main purpose of the present invention is to provide an air conditioning system and a control method to solve the technical problem that the compressor of the air conditioning system in the prior art is prone to liquid hammer.

[0005] In order to achieve the above object, according to one aspect of the present invention, an air conditioning system is provided, comprising:

[0006] Compressors and gas-liquid separators;

[0007] A heat exchange structure, the heat exchange structure has a first heat exchange channel and a second heat exchange channel for heat exchange, the inlet of the first heat exchange channel can be selectively connected or disconnected with the exhaust port of the compressor, the outlet of the first heat exchange channel is connected with the inlet of the gas-liquid separator, the inlet of the second heat exchange channel can be selectively connected or disconnected with the bottom of the gas-liquid separator, the outlet of the second heat exchange channel is connected with the air inlet of the compressor, and the first heat exchange channel is used to heat the second heat exchange channel.

[0008] Furthermore, the air conditioning system also includes:

[0009] A flow regulating valve is arranged on the connecting pipeline between the inlet of the second heat exchange channel and the bottom of the gas-liquid separator, and the flow opening size of the flow regulating valve is adjustable; and / or,

[0010] The switch valve is arranged on the connecting pipeline between the inlet of the first heat exchange channel and the exhaust port of the compressor.

[0011] Furthermore, the air conditioning system also includes:

[0012] The electronic expansion valve is arranged on the connecting pipeline between the inlet of the second heat exchange channel and the bottom of the gas-liquid separator, and the flow opening size of the electronic expansion valve can be adjusted.

[0013] Furthermore, the air conditioning system also includes:

[0014] The oil-liquid separator has an inlet connected to the exhaust port of the compressor, and the inlet of the first heat exchange channel is connected to the separation gas port of the oil-liquid separator.

[0015] Furthermore, the air conditioning system also includes:

[0016] A first temperature detection member is arranged at the exhaust port of the compressor to detect the temperature of the medium at the exhaust port of the compressor; and / or,

[0017] A second temperature detection element is provided at the gaseous refrigerant outlet of the gas-liquid separator to detect the medium temperature at the gaseous refrigerant outlet of the gas-liquid separator; and / or,

[0018] The third temperature detection component is arranged at the outlet of the second heat exchange channel to detect the medium temperature at the outlet of the second heat exchange channel.

[0019] Furthermore, the air conditioning system also includes:

[0020] A first pressure sensor is arranged at the exhaust port of the compressor to detect the exhaust side pressure value at the exhaust port of the compressor; and / or,

[0021] The second pressure sensor is arranged at the inlet of the gas-liquid separator to detect the suction side pressure value at the inlet of the gas-liquid separator.

[0022] According to another aspect of the present invention, a control method is provided, which is applicable to the air conditioning system provided above, and the control method includes:

[0023] Obtain the suction superheat value Ts of the air conditioning system;

[0024] Adjust the working condition of the heat exchange structure of the air conditioning system according to the suction superheat value Ts;

[0025] Among them, Ts=Tx-Tps, Tx value is the temperature value of the gaseous refrigerant outlet of the gas-liquid separator of the air-conditioning system, and Tps is the saturation temperature value corresponding to the exhaust side pressure value.

[0026] Furthermore, the working condition of the heat exchange structure of the air conditioning system is adjusted according to the suction superheat Ts, including:

[0027] When the suction superheat Ts is greater than the first preset temperature value, the inlet of the first heat exchange channel of the heat exchange structure is controlled to be disconnected from the exhaust port of the compressor of the air conditioning system, and the inlet of the second heat exchange channel of the heat exchange structure is disconnected from the bottom of the gas-liquid separator of the air conditioning system;

[0028] When the suction superheat Ts is less than or equal to the first preset temperature value, the inlet of the first heat exchange channel of the heat exchange structure is controlled to be connected to the exhaust port of the compressor of the air-conditioning system, and the inlet of the second heat exchange channel of the heat exchange structure is connected to the bottom of the gas-liquid separator of the air-conditioning system.

[0029] Furthermore, the air conditioning system is the air conditioning system provided above; when the suction air superheat Ts is less than or equal to the first preset temperature value, the control method further includes:

[0030] Obtain the reheat superheat value Tz of the air conditioning system;

[0031] The opening of the electronic expansion valve of the air conditioning system is adjusted according to the reheat superheat value Tz of the air conditioning system;

[0032] Wherein, Tz=Tm-Tps, Tm is the medium temperature value at the outlet of the second heat exchange channel.

[0033] Furthermore, the opening of the electronic expansion valve of the air conditioning system is adjusted according to the reheat superheat Tz of the air conditioning system, including:

[0034] When the reheat superheat value Tz is less than the second preset temperature value, the opening of the electronic expansion valve is controlled to decrease;

[0035] When the reheat superheat value Tz is greater than or equal to the second preset temperature value and less than or equal to the third preset temperature value, the opening of the electronic expansion valve is controlled to remain unchanged;

[0036] When the reheat superheat value Tz is greater than the third preset temperature value, the opening of the electronic expansion valve is controlled to increase.

[0037] Further, controlling the opening of the electronic expansion valve to decrease includes:

[0038] Controlling the opening of the electronic expansion valve to decrease at a preset opening reduction rate until the reheat superheat value is greater than or equal to a second preset temperature, or until the minimum opening of the electronic expansion valve is reached; and / or,

[0039] Control the opening of the electronic expansion valve to increase, including:

[0040] The opening of the electronic expansion valve is controlled to increase at a second preset opening increase rate until the reheat superheat degree is less than or equal to a third preset temperature, or until the maximum opening of the electronic expansion valve is reached.

[0041] By applying the technical solution of the present invention, when the inlet of the first heat exchange channel is connected with the exhaust port of the compressor and the inlet of the second heat exchange channel is connected with the bottom of the gas-liquid separator, the high-temperature and high-pressure gaseous refrigerant at the exhaust port of the compressor is introduced into the first heat exchange channel, and the liquid refrigerant at the bottom of the gas-liquid separator is introduced into the inlet of the second heat exchange channel. The high-temperature and high-pressure gaseous refrigerant in the first heat exchange channel is used to heat the liquid refrigerant in the second heat exchange channel, so that the liquid refrigerant is heated to gaseous refrigerant and then sent to the air inlet of the compressor. In addition, the higher temperature of the gaseous refrigerant will also heat the refrigerant flowing from the gaseous refrigerant outlet of the gas-liquid separator to the air inlet of the compressor, thereby reducing the amount of liquid refrigerant entering the air inlet of the compressor as a whole, and reducing the susceptibility of the compressor of the air-conditioning system to liquid hammer. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0043] Figure 1 A schematic diagram of the structure of an air conditioning system provided according to an embodiment of the present invention is shown;

[0044] Figure 2 A flow chart of a control method provided according to an embodiment of the present invention is shown.

[0045] The above drawings include the following reference numerals:

[0046] 10. Compressor; 20. Gas-liquid separator;

[0047] 30. heat exchange structure; 31. first heat exchange channel; 32. second heat exchange channel;

[0048] 40. Flow regulating valve; 50. Switch valve; 60. Oil-liquid separator; 70. First temperature detection element; 80. Second temperature detection element; 90. Third temperature detection element; 100. First pressure sensor; 110. Second pressure sensor; 120. Outdoor heat exchanger; 130. Subcooler; 140. Indoor unit; 150. Four-way valve; 160. Gas inlet pipe temperature sensing package; 170. Heating electronic expansion valve; 180. Subcooler solenoid valve. DETAILED DESCRIPTION

[0049] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0050] like Figure 1 As shown, embodiment 1 of the present invention provides an air-conditioning system, which includes a compressor 10, a gas-liquid separator 20 and a heat exchange structure 30, the heat exchange structure 30 having a first heat exchange channel 31 and a second heat exchange channel 32 for heat exchange, the inlet of the first heat exchange channel 31 can be selectively connected to or disconnected from the exhaust port of the compressor 10, the outlet of the first heat exchange channel 31 is connected to the inlet of the gas-liquid separator 20, the inlet of the second heat exchange channel 32 can be selectively connected to or disconnected from the bottom of the gas-liquid separator 20, the outlet of the second heat exchange channel 32 is connected to the air inlet of the compressor 10, and the first heat exchange channel 31 is used to heat the second heat exchange channel 32.

[0051] In the air-conditioning system provided by the present embodiment, when the inlet of the first heat exchange channel 31 is connected to the exhaust port of the compressor 10, and the inlet of the second heat exchange channel 32 is connected to the bottom of the gas-liquid separator 20, the high-temperature and high-pressure gaseous refrigerant at the exhaust port of the compressor 10 is introduced into the first heat exchange channel 31, and the liquid refrigerant at the bottom of the gas-liquid separator 20 is introduced into the inlet of the second heat exchange channel 32. The high-temperature and high-pressure gaseous refrigerant in the first heat exchange channel 31 is used to heat the liquid refrigerant in the second heat exchange channel 32, so that the liquid refrigerant is heated to gaseous refrigerant and then sent to the air inlet of the compressor 10. In addition, the higher temperature of the gaseous refrigerant will also heat the refrigerant flowing from the gaseous refrigerant outlet of the gas-liquid separator 20 to the air inlet of the compressor 10, thereby reducing the amount of liquid refrigerant entering the air inlet of the compressor 10 as a whole, reducing the susceptibility of the compressor 10 of the air-conditioning system to liquid hammer, improving the operating capacity of the air-conditioning system and the comfort of use of the air-conditioning system, and improving the reliability of the air-conditioning system. Therefore, the air conditioning system provided in this embodiment can solve the technical problem that the compressor 10 of the air conditioning system in the prior art is prone to liquid hammer.

[0052] Specifically, the first heat exchange channel 31 is separated from the second heat exchange channel 32. The first heat exchange channel 31 corresponds to a high-pressure gas circuit, and the second heat exchange channel 32 corresponds to a low-pressure liquid circuit. The high-pressure gas circuit and the low-pressure liquid circuit exchange heat in the heat exchange structure 30.

[0053] Specifically, the air conditioning system in this embodiment further includes a flow regulating valve 40, which is arranged on the connecting pipeline between the inlet of the second heat exchange channel 32 and the bottom of the gas-liquid separator 20, and the flow opening size of the flow regulating valve 40 is adjustable. In this way, the amount of liquid refrigerant flowing into the first heat exchange channel 31 can be adjusted by the flow regulating valve 40, so as to facilitate the control of the heating degree of the second heat exchange channel 32, so as to facilitate the adjustment of the temperature of the refrigerant flowing out of the second heat exchange channel 32, and realize the flexible and precise control of the refrigerant temperature heating, and better improve the operation stability, comfort and energy saving of the air conditioning system. Specifically, the flow regulating valve 40 has an open state and a closed state; when the flow regulating valve 40 is in a closed state, the inlet of the second heat exchange channel 32 is disconnected from the bottom of the gas-liquid separator 20, that is, the flow rate is zero at this time; when the flow regulating valve 40 is in an open state, the inlet of the second heat exchange channel 32 is connected to the bottom of the gas-liquid separator 20, and the flow rate at this time is not zero. Specifically, when the flow regulating valve 40 is in the open state, it has a minimum opening degree, and the minimum opening degree can be understood as a preset opening degree greater than zero.

[0054] Specifically, the flow regulating valve 40 may be an electronic expansion valve, an electric ball valve, a solenoid valve, or the like.

[0055] Preferably, the flow regulating valve 40 is an electronic expansion valve. In this way, the electronic expansion valve not only has the function of accurately adjusting the flow rate, but also has the function of throttling and reducing pressure, so that the refrigerant after the pressure reduction can absorb less heat to change the refrigerant temperature of the second heat exchange channel 32, thereby improving the heating effect of the refrigerant in the second heat exchange channel 32 and also achieving energy-saving effect.

[0056] Specifically, the air conditioning system in this embodiment further includes a switch valve 50, which is disposed on the connecting pipeline between the inlet of the first heat exchange channel 31 and the exhaust port of the compressor 10. In this way, the connection or disconnection between the inlet of the first heat exchange channel 31 and the exhaust port of the compressor 10 can be flexibly controlled according to actual needs, which is convenient for operation.

[0057] Specifically, the switch valve 50 may also be referred to as a bypass valve.

[0058] In this embodiment, the air conditioning system further includes an electronic expansion valve, which is arranged on the connecting pipeline between the inlet of the second heat exchange channel 32 and the bottom of the gas-liquid separator 20, and the flow opening size of the electronic expansion valve can be adjusted.

[0059] Specifically, the air conditioning system further includes an oil separator 60, the inlet of the oil separator 60 is connected to the exhaust port of the compressor 10, and the inlet of the first heat exchange channel 31 is connected to the separation port of the oil separator 60. With such a structural setting, the content of lubricating oil mixed in the refrigerant can be reduced, so as to ensure that the gaseous refrigerant enters the inlet of the first heat exchange channel 31 as much as possible, and the lubricating oil entering the inlet of the first heat exchange channel 31 is reduced as much as possible, so as to better reduce the content of lubricating oil mixed in the refrigerant during the circulation process, and better prevent the liquid hammer caused by the lubricating oil entering the compressor 10 for compression, thereby better reducing the liquid hammer phenomenon of the compressor 10.

[0060] Specifically, the air conditioning system further includes a first temperature detection member 70, which is disposed at the exhaust port of the compressor 10 to detect the medium temperature at the exhaust port of the compressor 10. In this way, it is convenient to obtain the exhaust gas superheat according to the difference between the temperature detected by the first temperature detection member 70 and the evaporation saturation temperature. Specifically, the temperature detected by the first temperature detection member 70 is Tp, the evaporation saturation temperature is Tpd, the exhaust gas superheat is Tg, and Tg=Tp-Tpd.

[0061] Specifically, the air conditioning system further includes a second temperature detection member 80, which is disposed at the outlet of the gaseous refrigerant of the gas-liquid separator 20 to detect the medium temperature at the outlet of the gaseous refrigerant of the gas-liquid separator 20. In this way, it is convenient to obtain the suction superheat according to the difference between the temperature detected by the second temperature detection member 80 and the condensation saturation temperature. Specifically, the temperature detected by the second temperature detection member 80 is Tx, which can be understood as the detection temperature of the suction pipe. The condensation saturation temperature is Tps, and the suction superheat is Ts, Ts = Tx-Tps.

[0062] Specifically, the air conditioning system further includes a third temperature detection member 90, which is disposed at the outlet of the second heat exchange passage 32 to detect the medium temperature at the outlet of the second heat exchange passage 32. In this way, the reheat superheat degree can be obtained according to the difference between the temperature detected by the third temperature detection member 90 and the condensation saturation temperature. Specifically, the temperature detected by the third temperature detection member 90 is Tm, and the reheat superheat degree is Tz, where Tz=Tm-Tps.

[0063] Specifically, the exhaust gas superheat is Tg, Tg = Tp - Tpd. In this embodiment, a fourth temperature detection element is also provided, and the fourth temperature detection element is used to detect the outdoor environment temperature Tenv, and the corresponding unit is °C.

[0064] Specifically, the first temperature detection member 70 , the second temperature detection member 80 and the third temperature detection member 90 may all be temperature sensing packages.

[0065] In this embodiment, the air conditioning system further includes a first pressure sensor 100, which is disposed at the exhaust port of the compressor 10 to detect the exhaust side pressure value at the exhaust port of the compressor 10. With such a structural arrangement, it is possible to determine the saturation temperature corresponding to the exhaust side pressure value according to the exhaust side pressure value, that is, the saturation temperature value corresponding to the condensing pressure, that is, the condensing saturation temperature, and the temperature unit is ° C.

[0066] In this embodiment, the air conditioning system further includes a second pressure sensor 110, which is disposed at the inlet of the gas-liquid separator 20 to detect the suction side pressure value at the inlet of the gas-liquid separator 20. With such a structural arrangement, it is convenient to determine the saturation temperature corresponding to the suction side pressure value according to the suction side pressure value, that is, the saturation temperature value corresponding to the evaporation pressure, that is, the evaporation saturation temperature, and the temperature unit is ° C.

[0067] Specifically, the pressure values ​​detected by the first pressure sensor 100 and the second pressure sensor 110 are transmitted to the main control board of the air-conditioning system, and the temperature value detected by the temperature sensing package is transmitted to the main control board.

[0068] It should be noted that the air conditioning system in this embodiment is based on the conventional air conditioning system in the prior art, and a bypass branch is added, and the heat exchange structure 30 is installed on the bypass branch. In this way, there is no need to change the normal operation function of the conventional air conditioning system, and the heating function of the refrigerant can be added on the basis of the normal operation of the air conditioning system, so as to minimize the content of liquid refrigerant entering the compressor 10, and better reduce the liquid hammer of the compressor 10. Specifically, the bypass branch includes two branches, one branch is provided with a first heat exchange channel 31 and a flow regulating valve 40, and the other branch is provided with a second heat exchange channel 32 and a switch valve 50.

[0069] Specifically, the air conditioning system in this embodiment further includes an outdoor heat exchanger 120, a subcooler 130, an indoor unit 140, a four-way valve 150, a gas inlet pipe temperature sensing package 160, a heating electronic expansion valve 170 and a subcooler solenoid valve 180. Specifically, the indoor unit 140 is connected to the outdoor heat exchanger 120 through a first pipeline, which is an air pipe. The indoor unit 140 is connected to the subcooler 130 through a second pipeline, which is a liquid pipe.

[0070] Embodiment 2 of the present invention provides a control method applicable to the air-conditioning system provided in the above embodiment, and the control method includes: obtaining the suction superheat value Ts of the air-conditioning system; adjusting the working condition of the heat exchange structure 30 of the air-conditioning system according to the size of the suction superheat value Ts; wherein Ts=Tx-Tps, Tx value is the temperature value at the gaseous refrigerant outlet of the gas-liquid separator 20 of the air-conditioning system, and Tps is the saturation temperature value corresponding to the exhaust side pressure value.

[0071] By adopting such a method, it is possible to adjust the working condition of the heat exchange structure 30 according to the size of the suction superheat value, so as to determine whether to control the heat exchange structure 30 to perform heating operation or disconnect or adjust the degree of heating, thereby flexibly realizing the regulation of the heating temperature of the refrigerant in the second heat exchange channel 32, thereby facilitating the regulation of the refrigerant temperature at the air inlet entering the compressor 10, and further, it is possible to better reduce the content of liquid refrigerant in the refrigerant entering through the air inlet of the compressor 10, thereby facilitating better reduction of liquid hammering of the compressor 10.

[0072] Specifically, the working condition of the heat exchange structure 30 of the air conditioning system is adjusted according to the size of the suction superheat Ts, including: when the suction superheat Ts is greater than the first preset temperature value, the inlet of the first heat exchange channel 31 of the heat exchange structure 30 is controlled to be disconnected from the exhaust port of the compressor 10 of the air conditioning system, and the inlet of the second heat exchange channel 32 of the heat exchange structure 30 is disconnected from the bottom of the gas-liquid separator 20 of the air conditioning system; when the suction superheat Ts is less than or equal to the first preset temperature value, the inlet of the first heat exchange channel 31 of the heat exchange structure 30 is controlled to be connected to the exhaust port of the compressor 10 of the air conditioning system, and the inlet of the second heat exchange channel 32 of the heat exchange structure 30 is connected to the bottom of the gas-liquid separator 20 of the air conditioning system. In this way, when Ts is large, it is convenient to determine that the refrigerant does not need to be heated, that is, the heat exchange structure 30 is in a stopped state, and the air conditioning system operates normally; when Ts is small, the heating structure can be put into operation in time to effectively heat the refrigerant in the second heat exchange channel 32 through the refrigerant in the first heat exchange channel 31.

[0073] Specifically, the medium temperature can be understood as the refrigerant temperature, and the first preset temperature value can be 2°C.

[0074] In this embodiment, the air conditioning system is the air conditioning system provided above; when the suction superheat Ts is less than or equal to the first preset temperature value, the control method further includes: obtaining the reheat superheat value Tz of the air conditioning system; adjusting the opening of the electronic expansion valve of the air conditioning system according to the reheat superheat value Tz of the air conditioning system; wherein Tz=Tm-Tps, Tm is the medium temperature value at the outlet of the second heat exchange channel 32. In this way, it is convenient to control the heating condition of the heat exchange structure 30 according to the medium temperature value at the outlet of the second heat exchange channel 32, thereby further improving the accuracy and flexibility of the control, avoiding the energy waste of overheating, and avoiding the situation that the liquid hammer is not effectively reduced due to insufficient heating.

[0075] Specifically, the opening of the electronic expansion valve of the air conditioning system is adjusted according to the magnitude of the reheat superheat Tz of the air conditioning system, including: when the reheat superheat value Tz is less than the second preset temperature value, the opening of the electronic expansion valve is controlled to decrease; when the reheat superheat value Tz is greater than or equal to the second preset temperature value and less than or equal to the third preset temperature value, the opening of the electronic expansion valve is controlled to remain unchanged; when the reheat superheat value Tz is greater than the third preset temperature value, the opening of the electronic expansion valve is controlled to increase. In this way, it is convenient to better control the opening of the electronic expansion valve according to the magnitude of the reheat superheat value in an adaptive, effective and flexible manner, so as to better realize the regulation of the temperature of the refrigerant in the second heat exchange channel 32 of the heat exchange structure 30.

[0076] Specifically, the second preset temperature value may be 2°C, and the third preset temperature value may be 10°C.

[0077] In this embodiment, controlling the opening of the electronic expansion valve to decrease includes: controlling the opening of the electronic expansion valve to decrease at a preset opening decrease rate until the reheat superheat value is greater than or equal to the second preset temperature, or until the minimum opening of the electronic expansion valve is reached. In this way, it is convenient to achieve flexible and accurate control of the flow reduction through the electronic expansion valve, and to achieve rapid control of the refrigerant temperature in the second heat exchange channel 32, and to avoid the situation where the reheat superheat value is reduced to too small.

[0078] Specifically, the preset opening degree reduction rate is 10 PLS every 20 seconds (20 seconds), and the minimum opening degree is 30 PLS.

[0079] Specifically, controlling the opening of the electronic expansion valve to increase includes: controlling the opening of the electronic expansion valve to increase at a second preset opening increase rate until the reheat superheat is less than or equal to a third preset temperature, or until the maximum opening of the electronic expansion valve is reached. In this way, it is convenient to achieve flexible and accurate control of the increase in flow rate through the electronic expansion valve, to achieve rapid increase control of the refrigerant temperature in the second heat exchange channel 32, and to avoid the situation where the reheat superheat value increases to an excessive value as much as possible.

[0080] Specifically, the preset opening increase rate is 10 PLS every 20 seconds (20 seconds), and the maximum opening is 480 PLS.

[0081] like Figure 2 As shown, the process of the control method of this embodiment is specifically as follows:

[0082] When the air conditioning system is in non-liquid return state:

[0083] When the air conditioning system is running, it will detect the operating parameters through the built-in temperature sensing package, sensors, etc., and make judgments. According to the built-in program, if the suction superheat is higher than 2°C, it is judged as a non-liquid return state, that is, the steam separation pipe does not carry a large amount of liquid refrigerant to the suction port of the compressor 10. At this time, the reheater (corresponding to the heat exchange structure 30) does not need to work, and the liquid return electronic expansion valve (corresponding to the flow control valve 40, also corresponding to Figure 2 The return liquid EXV in the bypass valve is kept closed, and the bypass valve (corresponding to the switch valve 50, specifically, the bypass valve also corresponds to Figure 2 The bypass solenoid valve in the valve remains closed.

[0084] When the air conditioning system is in liquid backflow state:

[0085] When the air intake superheat of the air conditioning system is lower than 2°C, it is determined that there is liquid return in the air conditioning system, that is, the refrigerant coming out of the outlet pipe of the gas-liquid separator 20 is not pure gas, but gas-liquid two-phase state, and contains a large amount of liquid refrigerant sucked into the compressor 10. At this time, the damage of the compressor 10 of the unit is not avoided, and the heat exchange capacity is improved. It is necessary to process the liquid return refrigerant and heat the liquid return refrigerant to a pure gas state to ensure that the compressor 10 inhales pure gas refrigerant. In order to ensure the best suction state of the compressor 10, the suction superheat is generally designed to be 2-10°C. Therefore, it is necessary to detect the temperature of the treated refrigerant through the outlet pipe temperature sensing package of the reheater. The concept of reheat superheat is introduced here. The reheat superheat can be understood as the superheat of the refrigerant heated by the reheater. If the reheat superheat is lower than 2°C, it means that the heating effect is not good, the incoming liquid refrigerant has not fully evaporated, and the flow rate needs to be reduced. At this time, the opening of the liquid return electronic expansion valve is reduced. On the contrary, if the reheat superheat is higher than 10°C, it means that the refrigerant coming out of the reheater is too superheated, resulting in overheating. It is necessary to increase the flow rate and increase the opening of the return liquid electronic expansion valve to ensure that more liquid refrigerant is heated. In the process of adjusting the return liquid electronic expansion valve, in order to avoid loss of control, the minimum opening is generally set, and the minimum opening can be set to about 30PLS; the maximum opening generally uses the physical maximum opening of the valve body, and can also be set separately. When the reheater is working, the state of the refrigerant changes, and the suction superheat of the compressor 10 will also be adjusted to within the range. When it is adjusted to within the range, it can be switched to normal control.

[0086] From the above description, it can be seen that the above-mentioned embodiments of the present invention achieve the following technical effects: improve the problem of rapid heating of the refrigerant in the liquid return part, shorten the heating time, improve the operating capacity and air-conditioning comfort of the air-conditioning system, extend the heating operation time, and improve the reliability of the air-conditioning system; improve the problem that the compressor suction refrigerant state cannot fully match the compressor operating state, the return air temperature and the return air volume do not match, improve the operating stability and energy saving, and avoid secondary liquid hammer.

[0087] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0088] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the application. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0089] In the description of the present application, it should be understood 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, and are only for the convenience of describing the present application 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, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0090] 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.

[0091] 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. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0092] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An air conditioning system, characterized in that: include: A compressor (10) and a gas-liquid separator (20); A heat exchange structure (30), the heat exchange structure (30) comprising a first heat exchange channel (31) and a second heat exchange channel (32) for performing heat exchange, the inlet of the first heat exchange channel (31) being selectively connected to or disconnected from the exhaust port of the compressor (10), the outlet of the first heat exchange channel (31) being connected to the inlet of the gas-liquid separator (20), the inlet of the second heat exchange channel (32) being selectively connected to or disconnected from the bottom of the gas-liquid separator (20), the outlet of the second heat exchange channel (32) being connected to the air inlet of the compressor (10), the first heat exchange channel (31) being used to heat the second heat exchange channel (32).

2. The air conditioning system according to claim 1, characterized in that: The air conditioning system further comprises: a flow regulating valve (40) disposed on a connecting pipeline between the inlet of the second heat exchange channel (32) and the bottom of the gas-liquid separator (20), wherein the flow opening of the flow regulating valve (40) is adjustable; and / or The switch valve (50) is arranged on the connecting pipeline between the inlet of the first heat exchange channel (31) and the exhaust port of the compressor (10).

3. The air conditioning system according to claim 1, characterized in that: The air conditioning system further comprises: An electronic expansion valve is arranged on the connecting pipeline between the inlet of the second heat exchange channel (32) and the bottom of the gas-liquid separator (20), and the flow opening size of the electronic expansion valve can be adjusted.

4. The air conditioning system according to claim 1, characterized in that: The air conditioning system further comprises: An oil-liquid separator (60), wherein the inlet of the oil-liquid separator (60) is communicated with the exhaust port of the compressor (10), and the inlet of the first heat exchange channel (31) is communicated with the separation gas port of the oil-liquid separator (60).

5. The air conditioning system according to claim 1, characterized in that: The air conditioning system further comprises: a first temperature detection element (70) disposed at the exhaust port of the compressor (10) to detect the temperature of the medium at the exhaust port of the compressor (10); and / or a second temperature detection element (80) disposed at the gaseous refrigerant outlet of the gas-liquid separator (20) to detect the medium temperature at the gaseous refrigerant outlet of the gas-liquid separator (20); and / or, A third temperature detection element (90) is arranged at the outlet of the second heat exchange channel (32) to detect the temperature of the medium at the outlet of the second heat exchange channel (32).

6. The air conditioning system according to claim 1, characterized in that: The air conditioning system further comprises: A first pressure sensor (100) is arranged at the exhaust port of the compressor (10) to detect the exhaust side pressure value at the exhaust port of the compressor (10); and / or, The second pressure sensor (110) is arranged at the inlet of the gas-liquid separator (20) to detect the suction side pressure value at the inlet of the gas-liquid separator (20).

7. A control method, characterized in that: Applicable to the air conditioning system according to any one of claims 1 to 6, the control method comprising: Obtaining a suction superheat value Ts of the air conditioning system; Adjusting the working condition of the heat exchange structure of the air conditioning system according to the suction superheat value Ts; Among them, Ts=Tx-Tps, Tx value is the temperature value of the gaseous refrigerant outlet of the gas-liquid separator of the air-conditioning system, and Tps is the saturation temperature value corresponding to the exhaust side pressure value.

8. The control method according to claim 7, characterized in that: The step of adjusting the working condition of the heat exchange structure of the air conditioning system according to the suction air superheat Ts includes: When the suction superheat Ts is greater than a first preset temperature value, the inlet of the first heat exchange channel of the heat exchange structure is controlled to be disconnected from the exhaust port of the compressor of the air conditioning system, and the inlet of the second heat exchange channel of the heat exchange structure is controlled to be disconnected from the bottom of the gas-liquid separator of the air conditioning system; When the suction superheat Ts is less than or equal to the first preset temperature value, the inlet of the first heat exchange channel of the heat exchange structure is controlled to be connected to the exhaust port of the compressor of the air-conditioning system, and the inlet of the second heat exchange channel of the heat exchange structure is controlled to be connected to the bottom of the gas-liquid separator of the air-conditioning system.

9. The control method according to claim 8, characterized in that: The air conditioning system is the air conditioning system according to claim 3; when the suction air superheat Ts is less than or equal to the first preset temperature value, the control method further includes: Obtaining a reheat superheat value Tz of the air conditioning system; Adjusting the opening of the electronic expansion valve of the air conditioning system according to the reheat superheat value Tz of the air conditioning system; Wherein, Tz=Tm-Tps, Tm is the medium temperature value at the outlet of the second heat exchange channel.

10. The control method according to claim 9, characterized in that: The step of adjusting the opening of the electronic expansion valve of the air conditioning system according to the reheat superheat degree Tz of the air conditioning system comprises: When the reheat superheat value Tz is less than a second preset temperature value, controlling the opening of the electronic expansion valve to decrease; When the reheat superheat value Tz is greater than or equal to the second preset temperature value and less than or equal to the third preset temperature value, controlling the opening of the electronic expansion valve to remain unchanged; When the reheat superheat value Tz is greater than the third preset temperature value, the opening degree of the electronic expansion valve is controlled to increase.

11. The control method according to claim 10, characterized in that: The controlling the opening degree of the electronic expansion valve to decrease includes: Controlling the opening of the electronic expansion valve to decrease at a preset opening reduction rate until the reheat superheat value is greater than or equal to the second preset temperature, or until the minimum opening of the electronic expansion valve is reached; and / or controlling the opening of the electronic expansion valve to increase, including: The opening of the electronic expansion valve is controlled to increase at a second preset opening increase rate until the reheat superheat degree is less than or equal to the third preset temperature, or until the maximum opening of the electronic expansion valve is reached.

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