Air conditioning system

Abstract

The invention discloses an air conditioning system, comprising: a compressor having an air suction port and an exhaust port; an indoor heat exchanger; an outdoor heat exchanger; the throttling device is connected between one end of the indoor heat exchanger and one end of the outdoor heat exchanger so as to change the pressure of the refrigerant; one end of the gas-liquid separation loop is connected with the gas suction port, and the gas-liquid separation loop is used for separating a gas-state refrigerant and a liquid-state refrigerant; the four-way valve is respectively connected with the other end of the gas-liquid separation loop, the exhaust port, the other end of the indoor heat exchanger and the other end of the outdoor heat exchanger so as to form a cooling circulation loop for a refrigerant to flow; the gas-liquid separation loop comprises a first branch circuit connected between the compressor and the four-way valve, and a second branch circuit connected between the compressor and the four-way valve and provided with a gas-liquid separator. The second branch and the first branch are arranged in parallel, and the second branch is connected between the compressor and the four-way valve; the first branch or the second branch is selectively opened, so that the refrigerant selectively flows through the gas-liquid separator, and the refrigerating and heating capacity of the air conditioner can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of air conditioning technology, and in particular to an air conditioning system. BACKGROUND

[0002] The air conditioner outdoor unit is matched with the indoor unit through refrigerant circulation, releases the heat collected by the indoor unit to the outside in the cooling mode, and absorbs the outside heat and delivers it to the indoor unit through the refrigerant in the heating mode. The air conditioner outdoor unit is generally equipped with a compressor and a gas-liquid separator. The gas-liquid separator is usually installed in front of the compressor suction port. Its main function is that before the refrigerant enters the compressor suction port, if there is liquid refrigerant, the liquid refrigerant is separated out through the gas-liquid separator, and only gaseous refrigerant enters the compressor, to prevent liquid refrigerant from entering the compressor and causing liquid impact on the compressor. However, after the refrigerant enters the gas-liquid separator, a certain pressure loss will be generated, resulting in a decrease in the air conditioning cooling or heating capacity.

[0003] In the related art, the existing air conditioner outdoor unit only uses one fixed gas-liquid separator, which continuously operates after the air conditioner is turned on, and the volume of the gas-liquid separator is fixed. The volume is the maximum volume under the most severe liquid return condition.

[0004] However, under various working conditions of the air conditioning system, only a small part of extreme conditions will appear liquid return, and the amount of liquid return is large or small, and the rest of the time will not appear liquid return. Using the gas-liquid separator when there is no liquid return will only reduce the cooling and heating capacity of the air conditioner, or when the amount of liquid return is very small, using a gas-liquid separator with a very large volume will also reduce the cooling and heating capacity of the air conditioning system. SUMMARY

[0005] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application proposes an air conditioning system, which selectively opens through the first branch or the second branch, so that the gas-liquid separator is only used when needed, avoiding resource waste, and can improve the cooling and heating capacity of the air conditioning system.

[0006] According to the air conditioning system of the first aspect of the present application, the air conditioning system comprises: a compressor having a suction port and a discharge port; an indoor heat exchanger; an outdoor heat exchanger; a throttling device connected between one end of the indoor heat exchanger and one end of the outdoor heat exchanger to change the pressure of the refrigerant; a gas-liquid separation circuit connected to the other end of the gas-liquid separation circuit and the suction port, the gas-liquid separator being used to separate gaseous refrigerant and liquid refrigerant; a four-way valve connected to the other end of the gas-liquid separation circuit, the discharge port, the other end of the indoor heat exchanger and the other end of the outdoor heat exchanger, respectively, to form a cooling circulation circuit for the refrigerant; the gas-liquid separation circuit comprises: a first branch connected between the compressor and the four-way valve, and a gas-liquid separator arranged on the first branch; a second branch arranged in parallel with the first branch and connected between the compressor and the four-way valve; wherein the first branch or the second branch is selectively opened to selectively flow through the gas-liquid separator.

[0007] According to the air conditioning system of the present application, by selectively opening the first branch or the second branch, the gas-liquid separator is only used when needed, avoiding resource waste, and the refrigeration and heating capacity of the air conditioning system can be improved.

[0008] According to some embodiments of the present application, a first control valve is arranged on the first branch, and the first control valve and the gas-liquid separator are arranged in series, and the first control valve is selectively opened; and a second control valve is arranged on the second branch, and the second control valve is selectively opened.

[0009] According to some embodiments of the present application, a temperature sensor and a pressure sensor are arranged between one end of the gas-liquid separator and the suction port of the compressor, the temperature sensor is used to obtain the temperature of one end of the gas-liquid separator, and the pressure sensor is used to obtain the pressure of one end of the gas-liquid separator.

[0010] According to some embodiments of the present application, the air conditioning system further comprises a controller, the controller is electrically connected with the first control valve and the second control valve, and the controller is configured to: when the air conditioning system is turned on, control the first control valve to open and the second control valve to close.

[0011] According to some embodiments of the present application, the controller is further configured to: after the air conditioning system runs for a first preset time, obtain a first difference value between a temperature value of the suction port of the compressor and a saturated evaporation temperature value corresponding to a pressure value of the suction port of the compressor; when the first difference value is greater than a first preset temperature, control the first control valve to close and the second control valve to open; when the first difference value is less than or equal to the first preset temperature, control the first control valve to open and the second control valve to close.

[0012] According to some embodiments of the present application, the first branch is at least two, the at least two first branches are in parallel with each other, and the at least two first branches are selectively opened to allow the refrigerant to selectively flow through the at least two gas-liquid separators.

[0013] According to some embodiments of the present application, the air conditioning system further comprises a controller electrically connected with the first control valve and the second control valve, and the controller is configured to control the at least two first control valves to be opened and the second control valve to be closed when the air conditioning system is started.

[0014] According to some embodiments of the present application, the controller is further configured to obtain a second difference between a temperature value of the suction port of the compressor and a saturated evaporation temperature value corresponding to a pressure value of the suction port of the compressor after the air conditioning system is operated for a second preset time, control one of the first control valves to be closed when the second difference is greater than a second preset temperature, and control the second control valve to be opened when the at least two first control valves are all closed.

[0015] According to some embodiments of the present application, the controller is further configured to control the first control valve to be opened and the second control valve to be closed when the second difference is less than or equal to the second preset temperature.

[0016] According to some embodiments of the present application, the air conditioning system of the second aspect comprises: a compressor having a suction port and a discharge port; an indoor heat exchanger; an outdoor heat exchanger; a throttling device connected between one end of the indoor heat exchanger and one end of the outdoor heat exchanger to change the pressure of the refrigerant; a gas-liquid separation circuit connected to the suction port, the gas-liquid separator being used to separate gaseous refrigerant and liquid refrigerant; a four-way valve connected to the other end of the gas-liquid separation circuit, the discharge port, the other end of the indoor heat exchanger, and the other end of the outdoor heat exchanger, thereby forming a cooling circulation circuit for the refrigerant; the gas-liquid separation circuit comprises: a first branch connected between the compressor and the four-way valve, and a gas-liquid separator is arranged on the first branch; and a second branch arranged in parallel with the first branch and connected between the compressor and the four-way valve; wherein the air conditioning system is configured to control the first branch to be opened and the second branch to be closed when a difference between a temperature value of the suction port of the compressor and a saturated evaporation temperature value corresponding to a pressure value of the suction port of the compressor is less than or equal to a third preset temperature.

[0017] Additional aspects and advantages of the present application will be partially given in the following description, partially will become apparent from the following description, or will be understood by those skilled in the art through the practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0018] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description, taken in conjunction with the following drawings of which:

[0019] Figure 1 is an embodiment one of an air conditioning system according to an embodiment of the present application;

[0020] Figure 2 is a control logic diagram of the embodiment one of the air conditioning system according to the embodiment of the present application;

[0021] Figure 3 is an embodiment two of an air conditioning system according to an embodiment of the present application;

[0022] Figure 4 is a control logic diagram of the embodiment two of the air conditioning system according to the embodiment of the present application.

[0023] Reference Signs:

[0024] 100, air conditioning system;

[0025] 11, compressor; 12, indoor heat exchanger; 13, outdoor heat exchanger; 14, throttling device; 15, four-way valve; 16, temperature sensor; 17, pressure sensor; 18, first branch; 181, first control valve; 182, gas-liquid separator; 19, second branch; 191, second control valve. DETAILED DESCRIPTION

[0026] Embodiments of the present application are described in detail below with reference to the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary, and embodiments of the present application are described in detail below.

[0027] Below, with reference to Figures 1-4 An air conditioning system 100 according to an embodiment of the present application is described.

[0028] With reference to Figure 1 shown, the air conditioning system 100 of the embodiment of the present application includes a compressor 11, an indoor heat exchanger 12, an outdoor heat exchanger 13, a throttling device 14, a gas-liquid separation circuit, and a four-way valve 15.

[0029] The compressor 11 is mainly used to compress gas, increase the pressure and temperature of the gas, and has a suction port and a discharge port. The compressor 11 sucks in low-temperature and low-pressure gaseous refrigerant from the suction port, compresses it by driving the piston with the motor, and discharges high-temperature and high-pressure liquid refrigerant to the discharge port to provide power for the refrigeration cycle.

[0030] For example, in the refrigeration mode, the compressor 11 is responsible for sucking in low-temperature and low-pressure gaseous refrigerant from the suction port, compressing it by driving the piston with the motor, and then discharging high-temperature and high-pressure liquid refrigerant to the discharge port. In this process, the refrigerant forms a high and low pressure difference in the pipeline, thereby realizing the refrigeration cycle, i.e., compression → condensation (heat release) → expansion → evaporation (heat absorption).

[0031] The specific types of refrigerants include Freon (R-12, R-22, R-134a, etc.), ammonia, hydrocarbon (such as R600a, R600, R290, etc.), carbon dioxide (CO2), etc.

[0032] The throttling device 14 is connected between one end of the indoor heat exchanger 12 and one end of the outdoor heat exchanger 13 to change the pressure of the refrigerant. The throttling device 14 is a device for regulating the flow of refrigerant, which mainly plays the role of throttling and pressure reduction by changing the pressure. Generally, there is a variable diameter in the device. When the refrigerant enters, the pressure will make the diameter smaller, thereby reducing the flow; when the refrigerant leaves, the pressure will make the diameter larger, thereby increasing the flow. Thus, it can effectively reduce the power consumption of the air conditioning system 100 and reduce the use cost.

[0033] The throttling device 14 can be an electronic expansion valve, a thermal expansion valve, or a capillary tube.

[0034] The electronic expansion valve can accurately control the flow of refrigerant. It can detect and collect data on multiple parameters such as the temperature difference of the air inlet and outlet of the air conditioner, the return air temperature and its set value, etc. according to the operating requirements of the air conditioning system 100, and automatically control the opening of the electronic expansion valve after microcomputer processing, thereby accurately controlling the flow of refrigerant in the air conditioning system 100, so as to maintain the refrigeration cycle in the best state.

[0035] The thermal expansion valve mainly senses the superheat degree of the refrigerant through the evaporator temperature sensing bag, thereby adjusting the valve opening of the expansion valve. When the superheat degree is high, it means that the evaporation is sufficient, and the refrigerant has become gaseous and superheated. At this time, the pressure in the diaphragm chamber increases, thereby pushing the valve rod downward to finally increase the valve opening. If the superheat degree is low, it means that the evaporation is not sufficient. At this time, the pressure in the diaphragm chamber decreases, and the diaphragm pushes the valve body upward to reduce the valve opening.

[0036] The capillary tube is simple in structure and low in cost. The capillary tube itself has a small diameter. When the refrigerant flows through the capillary tube, it needs to overcome the resistance in the pipeline, thereby generating a certain pressure drop. The smaller the pipe diameter and the longer the pipe length, the greater the pressure drop. Therefore, the adjustment of the capillary tube is mainly controlled according to the length of the pipeline.

[0037] The four-way valve 15 is connected with the other end of the gas-liquid separation assembly, the exhaust port, the other end of the indoor heat exchanger 12 and the other end of the outdoor heat exchanger 13 respectively, thereby forming a cooling cycle for the refrigerant. By switching the four-way valve 15, the flow direction of the refrigerant can be switched, and the operation mode of the system can be switched.

[0038] Taking the refrigeration mode as an example, when the air conditioning system 100 is working, the gaseous refrigerant is discharged from the compressor 11 and enters the outdoor heat exchanger 13 through the four-way valve 15 to be condensed and heat-exchanged, and then becomes liquid. The liquid refrigerant after heat exchange enters the indoor heat exchanger 12 through the throttling effect of the throttling device 14 to be evaporated and heat-exchanged, and then becomes gaseous.

[0039] Taking the heating mode as an example, when the air conditioning system 100 is working, the gaseous refrigerant is discharged from the compressor 11 and enters the indoor heat exchanger 12 through the four-way valve 15 to be condensed and heat-exchanged, and then becomes liquid. The liquid refrigerant after heat exchange enters the outdoor heat exchanger 13 through the throttling effect of the throttling device 14 to be evaporated and heat-exchanged, and then becomes gaseous.

[0040] In the above manner, the outdoor heat exchanger 13 and the indoor heat exchanger 12 have condensation and evaporation functions respectively. Compared with the prior art air conditioning system 100, in which the same heat exchanger needs to bear the functions of condensation and evaporation at the same time in different modes, the requirements of the heat exchanger are reduced, and the manufacturing cost of the heat exchanger is saved.

[0041] The gas-liquid separation circuit can include a first branch 18 connected between the compressor 11 and the four-way valve 15, and a gas-liquid separator 182 provided on the first branch 18.

[0042] The gas-liquid separator 182 is used to separate gaseous refrigerant and liquid refrigerant, which can be used to prevent liquid refrigerant from causing liquid hammer to the compressor 11, to ensure the safe and normal operation of the compressor 11, and additionally, the gas-liquid separator 182 can provide additional internal volume for the low-pressure side of the air conditioning system 100, to temporarily store excess liquid refrigerant, and to prevent the excess liquid refrigerant from flowing into the compressor 11.

[0043] The working principle of the gas-liquid separator 182 is mainly based on the density difference between gas and liquid and the hydrodynamic effect. When gas and liquid flow together, due to the difference in density, the liquid will deposit at the bottom to form a liquid phase, and the gas will be located at the upper part to form a gas phase, thereby realizing the separation of gas and liquid.

[0044] The gas-liquid separation circuit can further include a second branch 19 provided in parallel with the first branch 18 and connected between the compressor 11 and the four-way valve 15.

[0045] By setting the first branch 18 and the second branch 19, taking the refrigeration working condition as an example, the gaseous refrigerant after evaporative heat exchange with the indoor heat exchanger 12 can enter the first branch 18 after the four-way valve 15, and flow back to the compressor 11 after the gas-liquid separator 182, to complete a complete refrigeration cycle. The gaseous refrigerant can also enter the second branch 19, and then flow back to the compressor 11, to complete a complete refrigeration cycle.

[0046] Taking the heating working condition as an example, the gaseous refrigerant after evaporative heat exchange with the outdoor heat exchanger 13 can enter the first branch 18 after the four-way valve 15, and flow back to the compressor 11 after the gas-liquid separator 182, to complete a complete heating cycle. The gaseous refrigerant can also enter the second branch 19, and then flow back to the compressor 11, to complete a complete heating cycle.

[0047] Among them, the first branch 18 or the second branch 19 is selectively opened to make the refrigerant selectively flow through the gas-liquid separator 182. When the first branch 18 is opened and the second branch 19 is closed, the gas-liquid separator 182 is in operation, and the refrigerant passing through the gas-liquid separator 182 of the first branch 18 can separate the liquid refrigerant in the refrigerant. When the first branch 18 is closed and the second branch 19 is opened, the gas-liquid separator 182 is stopped from being used, and the refrigerant flows back to the compressor 11 through the second branch 19. In this way, whether the gas-liquid separator 182 is used can be controlled by controlling the opening and closing of the first branch 18 and the second branch 19, thereby improving the system efficiency.

[0048] For example, when there is no liquid return in the air conditioning system 100, the first branch 18 is closed and the second branch 19 is opened, which can avoid the refrigerant entering the gas-liquid separator 182 and affecting the refrigeration or heating effect of the air conditioning system 100. In addition, when the air conditioning system 100 has liquid return, the first branch 18 can be opened and the second branch 19 can be closed, so that the refrigerant enters the gas-liquid separator 182 to separate the liquid refrigerant, thereby preventing the liquid refrigerant from entering the compressor 11 and causing damage to the compressor 11.

[0049] Therefore, by selectively opening the first branch 18 or the second branch 19, the gas-liquid separator 182 is only used when needed, which can avoid resource waste and improve the refrigeration and heating capacity of the air conditioning system 100.

[0050] Referring to Figure 1 As shown in the figure, the first control valve 181 is arranged on the first branch 18, and the first control valve 181 and the gas-liquid separator 182 are arranged in series, and the first control valve 181 is selectively opened. The first control valve 181 and the gas-liquid separator 182 are arranged in series to control the opening or closing of the first branch 18.

[0051] The first control valve 181 can be an electromagnetic valve, which controls the valve state by controlling the on-off current of the electromagnetic coil, and can accurately control the refrigerant flow on the first branch 18.

[0052] The second control valve 191 is selectively opened. The second control valve 191 is used to control the opening or closing of the second branch 19. The second control valve 191 can be an electromagnetic valve, which controls the valve state by controlling the on-off current of the electromagnetic coil, and can accurately control the refrigerant flow on the second branch 19.

[0053] Referring to Figure 1 The temperature sensor 16 is used to obtain the temperature of one end of the gas-liquid separator 182, and the pressure sensor 17 is used to obtain the pressure of one end of the gas-liquid separator 182. By measuring the temperature and pressure of the refrigerant, it can be determined whether there is liquid return in the system.

[0054] Referring to Figure 2 The controller is electrically connected with the first control valve 181 and the second control valve 191. When the air conditioning system 100 is started, the controller controls the first control valve 181 to open and the second control valve 191 to close. Since the controller is electrically connected with the first control valve 181 and the second control valve 191, the controller can send an electrical signal to the first control valve 181 or the second control valve 191 to make it close or open. By opening or closing the first control valve 181 or the second control valve 191, the refrigerant flow through the first branch 18 or the second branch 19 is controlled.

[0055] After the air conditioning system 100 is started, the temperature sensor 16 and the pressure sensor 17 cannot measure the refrigerant and cannot determine whether there is liquid return in the air conditioning system 100, so the first control valve 181 is opened and the second control valve 191 is closed to make the refrigerant flow through the first branch 18, and the gas-liquid separator 182 operates to ensure that there is no liquid return in the air conditioning system 100 and to ensure the reliability of the compressor 11.

[0056] Referring to Figure 2 The controller is further configured to obtain a first difference between the temperature value of the suction port of the compressor 11 and the saturated evaporation temperature value corresponding to the pressure value of the suction port of the compressor 11 after the air conditioning system 100 runs for a first preset time. When the first difference is greater than a first preset temperature, the controller controls the first control valve 181 to close and the second control valve 191 to open. When the first difference is less than or equal to the first preset temperature, the controller controls the first control valve 181 to open and the second control valve 191 to close.

[0057] Whether the air conditioning system 100 has liquid return is determined by suction superheat. According to the formula of suction superheat = suction temperature - saturated evaporation temperature, the suction temperature and the saturated evaporation temperature of the refrigerant need to be obtained to determine the suction superheat.

[0058] The suction temperature can be measured by the temperature sensor 16. The saturated evaporation temperature and the pressure value of the suction port of the compressor 11 have a corresponding relationship. According to the refrigerant property parameter table, the corresponding saturated evaporation temperature can be found by the suction port pressure. The suction port pressure can be measured by the pressure sensor 17. The data measured by the temperature sensor 16 and the pressure sensor 17 are used to calculate and determine the value of the suction superheat, so that whether the air conditioning system 100 has liquid return can be determined.

[0059] In addition, the corresponding saturated evaporation temperature can also be calculated according to the suction port pressure by using some empirical formula, so as to calculate the value of the suction superheat.

[0060] That is, the first difference between the temperature value of the suction port of the compressor 11 and the saturated evaporation temperature corresponding to the pressure value of the suction port of the compressor 11 is the suction superheat.

[0061] The first difference is compared with the size of the first preset temperature. When the first difference is greater than the first preset temperature, it means that the suction superheat is large, the first control valve 181 is controlled to be closed, the second control valve 191 is controlled to be opened, and the refrigerant does not need to pass through the gas-liquid separator 182. When the first difference is less than or equal to the first preset temperature, it means that the suction superheat is insufficient, the first control valve 181 is controlled to be opened, the second control valve 191 is controlled to be closed, and the gas-liquid separator 182 is used.

[0062] Generally, the suction superheat is greater than zero degree, and it can be considered that the refrigerant has been completely evaporated and becomes a superheated gas, that is, all the gas enters the suction port of the compressor 11. If the suction superheat is less than or equal to zero degree, it means that there is liquid refrigerant entering the compressor 11, and the gas-liquid separator 182 is needed to separate the liquid refrigerant.

[0063] In the embodiment, the first preset temperature can be in the range of 1-2℃. The first preset temperature greater than zero degree can ensure that the suction superheat is greater than zero degree, and also has a certain suction superheat margin.

[0064] The first preset time can be 5-10 minutes. If the first preset time is too small, the system has not yet stabilized, and the measurement data of the pressure sensor 17 and the temperature sensor 16 are inaccurate, so that the suction superheat cannot be accurately determined. If the first preset time is too large, the system has no liquid return, but the suction superheat has not yet been determined, so that the gas-liquid separator 182 continues to operate, and the refrigeration and heating efficiency of the air conditioning system 100 is affected.

[0065] In summary, referring to FIG. 1, Figure 2 The control logic of the air conditioning system 100 is as follows: after the air conditioning system 100 is started, the controller controls the first control valve 181 to open and the second control valve 191 to close. After running for a first preset time, the first difference and the first preset temperature are compared. If the first difference is greater than the first preset temperature, the first control valve 181 is closed, the second control valve 191 is opened, and the first difference and the first preset temperature are compared again after the air conditioning system 100 runs for the first preset time.

[0066] If the first difference is less than or equal to the first preset temperature, the first control valve 181 is opened, the second control valve 191 is closed, and the first difference and the first preset temperature are compared again after running for the first preset time.

[0067] Each time the first control valve 181 and the second control valve 191 are changed, the operation needs to be repeated until the air conditioning system 100 is closed.

[0068] Referring to FIG. 1, Figure 3 The first branch 18 can also be at least two. The at least two first branches 18 are connected in parallel, and the at least two first branches 18 are selectively opened to allow the refrigerant to selectively flow through the at least two gas-liquid separators 182.

[0069] In some outdoor air conditioners with a large number of matches, the refrigerant amount is large, and a large-capacity gas-liquid separator 182 is used. Under normal working conditions, a large-capacity gas-liquid separator 182 is not required to prevent the compressor 11 from returning liquid, and the use of a large-capacity gas-liquid separator 182 will reduce the performance of the air conditioner.

[0070] By setting multiple first branches 18, the gas-liquid separator 182 volume in the multiple first branches 18 is relatively reduced compared to the original gas-liquid separator 182, but the number of gas-liquid separators 182 is increased, and the total gas-liquid separator 182 volume does not decrease, and can meet the required volume under the most severe liquid return condition. Since the multiple first branches 18 are arranged in parallel, the first control valve 181 is arranged on each first branch 18, so that the gas-liquid separator 182 in each first branch 18 can be controlled individually, and the number and volume of the gas-liquid separator 182 in use can be flexibly adjusted, thereby improving the refrigeration and heating capacity of the air conditioning system 100.

[0071] The number of first branches 18 can be two, three, four, or more.

[0072] Referring to Figure 4 The air conditioning system 100 further includes a controller, the controller is electrically connected with the first control valve 181 and the second control valve 191, and the controller is configured to: when the air conditioning system 100 is started, control at least two first control valves 181 to be opened and the second control valve 191 to be closed. Since the controller is electrically connected with the first control valve 181 and the second control valve 191, the controller can send an electrical signal to the first control valve 181 or the second control valve 191 to make it close or open, and the refrigerant flow through the first branch 18 or the second branch 19 is controlled by opening or closing the first control valve 181 or the second control valve 191.

[0073] After the air conditioning system 100 is started, the first control valve 181 is opened and the second control valve 191 is closed, so that the refrigerant flows through the first branch 18 and the gas-liquid separator 182 operates, ensuring that there is no liquid return in the system and ensuring the reliability of the compressor 11.

[0074] Referring to Figure 4 The controller is further configured to: after the air conditioning system 100 runs for a second preset time, obtain a second difference between a temperature value of the suction port of the compressor 11 and a saturated evaporation temperature value corresponding to a pressure value of the suction port of the compressor 11; when the second difference is greater than a second preset temperature, control one of the first control valves 181 to be closed, and when all the first control valves 181 are closed, control the second control valve 191 to be opened. In addition, the controller is further configured to: when the second difference is less than or equal to the second preset temperature, control the first control valve 181 to be opened and the second control valve 191 to be closed.

[0075] The second difference between the temperature value of the suction port of the compressor 11 and the saturated evaporation temperature value corresponding to the pressure value of the suction port of the compressor 11 is the suction superheat.

[0076] The second difference is compared with the second preset temperature. If the second difference is greater than the second preset temperature, it indicates that the intake superheat is too high. One of the first control valves 181 is closed to reduce the volume of the gas-liquid separator 182. This process is repeated until all first control valves 181 are closed. Then, the second control valve 191 is opened, and the gas-liquid separator 182 is not needed. If the second difference is less than or equal to the second preset temperature, it indicates that the intake superheat is insufficient. One of the first control valves 181 is opened, and the second control valve 191 is closed. The gas-liquid separator 182 is used. If, after repeated checks, all first control valves 181 have been opened, but the second difference is still less than or equal to the second preset temperature, the current state must be maintained.

[0077] In this embodiment, the value of the second preset temperature can be in the range of 1-2℃. The second preset temperature being greater than zero degrees can ensure that the intake superheat is greater than zero degrees while also having a certain intake superheat margin.

[0078] Furthermore, the second preset time can range from 5 to 10 minutes. If the second preset time is too short, the system is not yet running stably, and the measurement data from pressure sensor 17 and temperature sensor 16 will be inaccurate, making it impossible to accurately determine the intake superheat. If the second preset time is too long, it is easy for the system to have no return liquid but the intake superheat has not yet been determined, causing the gas-liquid separator 182 to continue operating, affecting the cooling and heating efficiency of the air conditioning system 100.

[0079] In summary, referring to Figure 4 As shown, the control logic of the air conditioning system 100 is as follows: After the air conditioning system 100 is turned on, the controller controls all first control valves 181 to open and second control valves 191 to close. After running for a second preset time, the second difference is compared with the second preset temperature. If the second difference is greater than the second preset temperature, one first control valve 181 is closed. After the air conditioning system 100 runs for a second preset time, the second difference is compared with the second preset temperature. The above steps are repeated. If all first control valves 181 are closed, the second control valves 191 are opened. After the air conditioning system 100 runs for a second preset time, the second difference is compared with the second preset temperature again.

[0080] If the second difference is less than or equal to the second preset temperature, one of the first control valves 181 will open, and the second control valve 191 will remain closed. After running for a second preset time, the second difference will be compared with the first preset temperature again until all the first control valves 181 are open, and then the status quo will be maintained.

[0081] Each time the first control valve 181 and the second control valve 191 are changed, the operation needs to be repeated until the air conditioning system 100 is shut down.

[0082] Referring to Figure 1 and Figure 3 As shown in the figure, the application further provides an air conditioning system 100, comprising a compressor 11, an indoor heat exchanger 12, an outdoor heat exchanger 13, a throttling device 14, a gas-liquid separation circuit and a four-way valve 15.

[0083] The gas-liquid separation circuit can comprise a first branch 18 connected between the compressor 11 and the four-way valve 15, and a gas-liquid separator 182 provided on the first branch 18.

[0084] The gas-liquid separator 182 is used to separate gaseous refrigerant and liquid refrigerant, which can be used to prevent liquid refrigerant from causing liquid hammer to the compressor 11, ensure the safe and normal operation of the compressor 11, and additionally provide additional internal volume for the low-pressure side of the air conditioning system 100 to temporarily store excess liquid refrigerant and prevent excess liquid refrigerant from flowing into the compressor 11.

[0085] The working principle of the gas-liquid separator 182 is mainly based on the density difference of gas and liquid and the hydrodynamic effect. When gas and liquid flow together, due to the difference in density, the liquid will deposit at the bottom to form a liquid phase, and the gas will be located at the upper part to form a gas phase, thereby realizing the separation of gas and liquid.

[0086] The gas-liquid separation circuit can further comprise a second branch 19 provided in parallel with the first branch 18 and connected between the compressor 11 and the four-way valve 15.

[0087] By providing the first branch 18 and the second branch 19, taking the refrigeration working condition as an example, the gaseous refrigerant after evaporative heat exchange with the indoor heat exchanger 12 can enter the first branch 18 after the four-way valve 15, flow back to the compressor 11 after the gas-liquid separator 182, and complete a complete refrigeration cycle. The gaseous refrigerant can also enter the second branch 19 and then flow back to the compressor 11 to complete a complete refrigeration cycle.

[0088] Taking the heating working condition as an example, the gaseous refrigerant after evaporative heat exchange with the outdoor heat exchanger 13 can enter the first branch 18 after the four-way valve 15, flow back to the compressor 11 after the gas-liquid separator 182, and complete a complete heating cycle. The gaseous refrigerant can also enter the second branch 19 and then flow back to the compressor 11 to complete a complete heating cycle.

[0089] The air conditioning system 100 is configured to: when the difference between the temperature value of the suction port of the compressor 11 and the saturated evaporation temperature value corresponding to the pressure value of the suction port of the compressor 11 is less than or equal to a third preset temperature, control the first branch 18 to be opened and the second branch 19 to be closed.

[0090] Whether the air conditioning system 100 has liquid return is judged by suction superheat. According to the formula of suction superheat = suction temperature - saturated evaporation temperature, the suction temperature and the saturated evaporation temperature of the refrigerant need to be obtained to judge the suction superheat.

[0091] Referring to Figure 1 and Figure 3 , the suction temperature can be measured by the temperature sensor 16, the saturated evaporation temperature and the pressure value of the suction port of the compressor 11 have a corresponding relationship, according to the refrigerant property parameter table, the corresponding saturated evaporation temperature can be found out by the suction port pressure, the suction port pressure can be measured by the pressure sensor 17, the data measured by the temperature sensor 16 and the pressure sensor 17 are used to calculate and judge the value of the suction superheat, so that whether the air conditioning system 100 has liquid return can be judged.

[0092] In addition, the corresponding saturated evaporation temperature can also be calculated according to the suction port pressure by using some empirical formula, so as to calculate the value of the suction superheat.

[0093] That is, the difference between the temperature value of the suction port of the compressor 11 and the saturated evaporation temperature value corresponding to the pressure value of the suction port of the compressor 11 is the suction superheat.

[0094] Generally, the suction superheat is greater than zero, which can be considered that the refrigerant has been completely evaporated into superheated gas, that is, all the gas enters the suction port of the compressor 11, if the suction superheat is less than or equal to zero, it means that there is liquid refrigerant entering the compressor 11, which needs to be separated by the gas-liquid separator 182.

[0095] Therefore, by comparing the suction superheat with the third preset temperature, whether the liquid refrigerant enters the compressor 11 can be judged, so as to judge whether the gas-liquid separator 182 needs to be used.

[0096] Specifically, when the difference between the temperature value of the suction port of the compressor 11 and the saturated evaporation temperature value corresponding to the pressure value of the suction port of the compressor 11 is less than or equal to the third preset temperature, it means that the suction superheat is insufficient, the first branch 18 is opened and the second branch 19 is closed, the gas-liquid separator 182 is used to separate the liquid refrigerant in the refrigerant, so as to prevent the liquid refrigerant from entering the compressor 11 and causing damage to the compressor 11.

[0097] Similarly, when the difference between the temperature value of the suction port of the compressor 11 and the saturated evaporation temperature value corresponding to the pressure value of the suction port of the compressor 11 is greater than the third preset temperature, it means that the suction superheat is large, the first branch 18 is closed and the second branch 19 is opened, the gas-liquid separator 182 is not used, and the refrigerating and heating effect of the air conditioning system 100 is improved.

[0098] In the embodiment, the third preset temperature can be 1-2℃, and the third preset temperature greater than zero can ensure that the suction superheat is greater than zero and has a certain suction superheat margin.

[0099] Therefore, the first branch 18 and the second branch 19 are opened or closed according to the suction superheat, the gas-liquid separator 182 is used only when needed, resource waste is avoided, and the refrigeration and heating capacity of the air conditioning system 100 can be improved.

[0100] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0101] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "illustrative embodiment", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example.

[0102] Although the embodiments of the present application have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. An air conditioning system, comprising: a compressor having a suction port and a discharge port; an indoor heat exchanger; an outdoor heat exchanger; a throttling device connected between one end of the indoor heat exchanger and one end of the outdoor heat exchanger to change the pressure of refrigerant; a gas-liquid separation circuit having one end connected to the suction port, the gas-liquid separator being configured to separate gaseous refrigerant and liquid refrigerant; a four-way valve connected to the other end of the gas-liquid separation circuit, the discharge port, the other end of the indoor heat exchanger, and the other end of the outdoor heat exchanger, respectively, to form a cooling cycle circuit for refrigerant flow; characterized in that the gas-liquid separation circuit comprises: a first branch connected between the compressor and the four-way valve, and having a gas-liquid separator disposed thereon; a second branch connected between the compressor and the four-way valve in parallel with the first branch; wherein the first branch or the second branch is selectively opened to allow refrigerant to selectively flow through the gas-liquid separator.

2. The air conditioning system of claim 1, wherein, a first control valve is disposed on the first branch, and the first control valve and the gas-liquid separator are connected in series, and the first control valve is selectively opened; and a second control valve is disposed on the second branch, and the second control valve is selectively opened.

3. The air conditioning system of claim 2, wherein, a temperature sensor and a pressure sensor are disposed between one end of the gas-liquid separator and the suction port of the compressor, the temperature sensor being configured to obtain the temperature of one end of the gas-liquid separator, and the pressure sensor being configured to obtain the pressure of one end of the gas-liquid separator.

4. The air conditioning system of claim 3, wherein further comprising: a controller electrically connected to the first control valve and the second control valve, the controller being configured to: when the air conditioning system is turned on, control the first control valve to open and the second control valve to close.

5. The air conditioning system of claim 4, wherein, the controller is further configured to: after the air conditioning system runs for a first predetermined time, obtain a first difference between a saturation evaporation temperature value corresponding to a temperature value of the suction port of the compressor and a pressure value of the suction port of the compressor; when the first difference is greater than a first predetermined temperature, control the first control valve to close and the second control valve to open; when the first difference is less than or equal to the first predetermined temperature, control the first control valve to open and the second control valve to close.

6. The air conditioning system of claim 3, wherein the first branch is at least two, at least two first branches are connected in parallel with each other, and at least two first branches are selectively opened to allow refrigerant to selectively flow through at least two gas-liquid separators.

7. The air conditioning system of claim 6, wherein further comprising: a controller electrically connected to the first control valve and the second control valve, the controller being configured to: when the air conditioning system is turned on, control at least two first control valves to open and the second control valve to close.

8. The air conditioning system of claim 7, wherein, the controller is further configured to: after the air conditioning system runs for a second predetermined time, obtain a second difference between a saturation evaporation temperature value corresponding to a temperature value of the suction port of the compressor and a pressure value of the suction port of the compressor; When the second difference is greater than the second preset temperature, the controller controls one of the first control valves to be closed, and controls the second control valve to be opened when all of the first control valves are closed.

9. The air conditioning system of claim 8, wherein, The controller is further configured to control the first control valves to be opened and the second control valve to be closed when the second difference is less than or equal to the second preset temperature.

10. An air conditioning system comprising: a compressor having a suction port and a discharge port; an indoor heat exchanger; an outdoor heat exchanger; a throttling device connected between one end of the indoor heat exchanger and one end of the outdoor heat exchanger to change the pressure of refrigerant; a gas-liquid separation circuit having one end connected to the suction port, the gas-liquid separator being configured to separate gaseous refrigerant and liquid refrigerant; a four-way valve connected to the other end of the gas-liquid separation circuit, the discharge port, the other end of the indoor heat exchanger, and the other end of the outdoor heat exchanger, respectively, to form a cooling cycle circuit for refrigerant flow; characterized in that the gas-liquid separation circuit comprises: a first branch connected between the compressor and the four-way valve, and having a gas-liquid separator disposed thereon; a second branch connected in parallel with the first branch and between the compressor and the four-way valve; wherein the air conditioning system is configured to control the first branch to be opened and the second branch to be closed when the difference between the temperature value of the suction port of the compressor and the saturated evaporation temperature value corresponding to the pressure value of the suction port of the compressor is less than or equal to a third preset temperature.

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