Air conditioning system

Abstract

The application provides an air conditioning system, comprising an outdoor unit, an indoor unit and a water module, a second electronic expansion valve is connected with the outdoor unit through a high-pressure gas pipe, and a third electronic expansion valve is connected with the outdoor unit through a low-pressure gas pipe; a controller is configured to: determine a working mode of the outdoor unit and a capacity proportion of a refrigeration side indoor unit based on operating conditions of the multiple indoor units and the water module; determine a refrigerant management mode based on a comparison relationship between the working mode of the outdoor unit and the capacity proportion of the refrigeration side indoor unit and a preset threshold; determine whether system operation characteristic parameters meet a preset triggering condition, if yes, obtain a refrigerant control strategy corresponding to the refrigerant management mode, and control the opening degrees of the first, second and third electronic expansion valves. The application effectively solves the problem of abnormal refrigerant distribution caused by the imbalance of cold and heat loads, and avoids poor refrigeration effect, excessively high exhaust temperature, system high-pressure alarm and other faults.

Description

Technical Field

[0001] This invention relates to the technical field of air conditioners, and particularly to an air conditioning system. Background Technology

[0002] Multi-split air conditioning systems, with their flexible unit configurations and high operational efficiency, have been widely used in various building scenarios. As user needs diversify, multi-split systems not only need to provide conventional cooling and heating functions but also expanded capabilities such as condensate heat recovery for hot water production. Three-pipe multi-split systems emerged to meet this demand. By adding a switching device, they overcome the limitation of traditional models that cannot simultaneously cool or heat, allowing different indoor units to operate in cooling or heating modes as needed. This greatly improves operational flexibility and better adapts to the varying cooling and heating requirements of different areas within the same space.

[0003] However, when the ratio of indoor units operating in cooling and heating modes is severely imbalanced, there will be a noticeable problem of uneven refrigerant distribution. For example, if there are few indoor units operating in cooling mode and many indoor units shut down in heating mode, a large amount of refrigerant will remain in the pipes and internal components of the indoor units shut down in heating mode. This will cause the operating indoor units in cooling mode to experience insufficient refrigerant supply, resulting in reduced cooling performance and decreased energy efficiency. This issue needs to be addressed.

[0004] In existing technologies, the main solutions to refrigerant distribution imbalance are increasing compressor frequency to increase refrigerant output or adding refrigerant recovery loops and pumps to draw refrigerant retained in the shut-down indoor units back into the system's main circulation. However, these methods still have significant drawbacks: First, the adjustment precision is insufficient. Existing solutions are mostly passive compensation-based adjustments, and when the indoor unit's operating mode, number of starts / stops, and cooling / heating load ratio fluctuate frequently, the control response is lagging, making it difficult to achieve rapid and accurate dynamic balance of the refrigerant. Second, system energy consumption increases significantly. Some solutions require additional driving of the recovery pump or long-term increase in compressor operating frequency, which not only increases overall energy consumption but also exacerbates wear and tear on core components and shortens equipment lifespan. Third, the system structure becomes more complex. Adding a large number of recovery pumps and pipelines increases manufacturing costs, increases the probability of failure, and increases the difficulty of later installation and maintenance. Therefore, existing technologies are poorly adaptable to complex operating conditions such as moderate cooling / heating load imbalance and frequent start / stop of indoor units, making it difficult to simultaneously achieve both refrigerant distribution precision and system operating efficiency.

[0005] In view of the above, this application is hereby submitted. Summary of the Invention

[0006] The present invention aims to at least partially solve the technical problems in the related art.

[0007] Therefore, according to embodiments of this disclosure, an air conditioning system is proposed, comprising: Outdoor unit; Indoor unit, including: Multiple indoor units, each of which is connected to a first electronic expansion valve, and the multiple first electronic expansion valves are connected to the outdoor unit through refrigerant pipelines; At least one water module, the water module being connected to the outdoor unit and the indoor unit via the refrigerant piping; The switching device includes a second electronic expansion valve and a third electronic expansion valve. Both the second electronic expansion valve and the third electronic expansion valve are connected to the indoor unit through refrigerant pipelines. The second electronic expansion valve is connected to the outdoor unit through a high-pressure gas pipe in the refrigerant pipelines, and the third electronic expansion valve is connected to the outdoor unit through a low-pressure gas pipe in the refrigerant pipelines. The controller, wherein the controller is configured to: The operating conditions and system operating characteristic parameters of multiple indoor units and water modules are obtained, wherein the system operating characteristic parameters include the evaporative superheat of the indoor unit, the opening degree of the first electronic expansion valve, and the refrigerant high pressure value of the outdoor unit. Based on the operating conditions of the multiple indoor units and the water module, the operating mode of the outdoor unit is determined; When the water module and some of the indoor units stop operating, the capacity ratio of the cooling-side indoor units is determined. The refrigerant management mode is determined based on the comparison between the working mode of the outdoor unit and the capacity ratio of the indoor unit on the cooling side and a preset threshold. Different refrigerant management modes are configured with corresponding refrigerant control strategies. Determine whether the system operating characteristic parameters meet the preset trigger conditions. If so, obtain the refrigerant control strategy corresponding to the refrigerant management mode, and control the opening degree of the first electronic expansion valve, the second electronic expansion valve and the third electronic expansion valve based on the refrigerant control strategy to adjust the refrigerant circulation volume in the refrigerant pipeline.

[0008] In the above technical solution, the controller can acquire the operating conditions and system operating characteristic parameters of the indoor unit and water module in real time, accurately identify the system load distribution and refrigerant allocation status, and automatically match the corresponding refrigerant management mode based on the outdoor unit's operating status and the capacity ratio of the indoor units on the cooling side. When preset trigger conditions are met, it executes a precise refrigerant control strategy, realizing the coordinated adjustment of the first electronic expansion valve, the second electronic expansion valve, and the third electronic expansion valve. It can dynamically balance the refrigerant circulation volume, effectively solve the problem of abnormal refrigerant distribution caused by the imbalance of cooling and heating load ratios, avoid faults such as poor cooling effect, excessively high exhaust temperature, and system high-pressure alarm, significantly improve the operational stability, reliability, and environmental adaptability of the air conditioning system, while ensuring that the user experience is not affected.

[0009] In some embodiments, the controller is further configured to determine the operating mode of the outdoor unit based on the operating conditions of the plurality of indoor units and the water module, including: When the initial heating demand of the system is greater than the cooling demand, and the outdoor heat exchanger of the outdoor unit is running as an evaporator, when all the indoor units and water modules corresponding to the heating state are shut down, and only the indoor units in the cooling state are running, the outdoor heat exchanger switches to condenser operation. When the initial cooling demand of the system is greater than the heating demand, and the outdoor heat exchanger is operating as a condenser, when all indoor units and water modules corresponding to the cooling state are shut down, and only the indoor units in the heating state are running, the outdoor heat exchanger switches to evaporator operation.

[0010] In the above technical solution, the controller can accurately determine whether the outdoor heat exchanger should be in condenser mode or evaporator mode based on the cooling and heating operation status of the indoor unit and water module. This enables accurate identification and mode locking of the system's operating conditions, avoiding refrigerant regulation logic confusion due to mode misjudgment. It ensures a high degree of matching between the refrigerant control strategy and the actual system operating status, providing a reliable and accurate basis for subsequent refrigerant management mode determination and refrigerant circulation adjustment. This improves the rigor and effectiveness of the overall control logic, ensuring stable switching and safe operation of the system under different operating conditions.

[0011] In some embodiments, the controller is further configured to: determine a refrigerant management mode based on a comparison between the operating mode of the outdoor unit and the capacity ratio of the cooling-side indoor unit and a preset threshold, including: When the outdoor heat exchanger is running as a condenser, it is determined whether the capacity ratio of the indoor unit on the cooling side is not greater than a first preset threshold. If so, the first refrigerant management mode is activated. When the outdoor heat exchanger is running as an evaporator, it is determined whether the capacity ratio of the indoor unit on the cooling side is not less than the second preset threshold. If so, the second refrigerant management mode is run.

[0012] In the above technical solution, based on the operating mode of the outdoor heat exchanger and the comparison between the indoor unit capacity ratio on the cooling side and the first and second preset thresholds, the first or second refrigerant management mode is activated according to different scenarios, realizing the classification, identification, and refined control of abnormal refrigerant conditions. It can address both "insufficient refrigerant" and "excessive refrigerant and high pressure" fault conditions, avoiding the shortcomings of a single adjustment logic that cannot adapt to complex heating and cooling imbalance scenarios. This significantly improves the system's adaptability to extreme load changes, making refrigerant adjustment more targeted, timely, and reasonable, and improving the overall operating efficiency of the system.

[0013] In some embodiments, the controller is further configured to determine whether the system operating characteristic parameters meet preset triggering conditions; if so, to obtain the refrigerant control strategy corresponding to the refrigerant management mode, including: When the first refrigerant management mode is activated, the opening degree of the first electronic expansion valve corresponding to the indoor unit in the cooling state is obtained from the system operation characteristic parameters, and it is determined whether the opening degree of the first electronic expansion valve is not less than the preset opening degree threshold. If so, then obtain the evaporative superheat of the indoor unit in the cooling state from the system operation characteristic parameters, and determine whether the evaporative superheat is not less than the preset superheat threshold. If the evaporation superheat is not less than the preset superheat threshold, then the first refrigerant control strategy is executed.

[0014] In the above technical solution, under the first refrigerant management mode, by simultaneously judging the opening degree of the first electronic expansion valve and the evaporative superheat of the indoor unit, the system can accurately and reliably identify the condition of insufficient refrigerant circulation, effectively avoiding false triggering and adjustment caused by parameter fluctuations. Combining valve position characteristics and temperature characteristics as dual indicators improves the accuracy of refrigerant anomaly identification, providing a reliable prerequisite for the execution of refrigerant control strategies. This ensures that refrigerant replenishment is initiated only when truly needed, enhancing system control stability and reducing pressure fluctuations and increased energy consumption caused by ineffective adjustments.

[0015] In some embodiments, the controller is further configured to control the opening degrees of the first electronic expansion valve, the second electronic expansion valve, and the third electronic expansion valve based on the refrigerant control strategy to adjust the refrigerant circulation volume in the refrigerant pipeline, including: When the first refrigerant control strategy is running, the indoor unit that meets the preset standard in the heating state is selected as the first target indoor unit; Control the closure of the first electronic expansion valve corresponding to the first target indoor unit; The control closes the second electronic expansion valve connected to the first target indoor unit and opens the third electronic expansion valve connected to the first target indoor unit.

[0016] In the above technical solution, under the first refrigerant control strategy, by selecting a first target indoor unit that meets the standard, and executing coordinated control of closing the first electronic expansion valve, closing the second electronic expansion valve, and opening the third electronic expansion valve, the heat exchanger of the target indoor unit can be forcibly switched from the high-pressure side condenser to the low-pressure side evaporator, quickly releasing the large amount of refrigerant stored inside and replenishing it to the system circulation. This can directly and efficiently increase the refrigerant supply to the indoor unit operating in cooling mode, rapidly improving problems such as poor cooling effect, high evaporation superheat, and high exhaust temperature caused by insufficient refrigerant, restoring the system's normal heat exchange capacity, and improving the user's cooling experience.

[0017] In some embodiments, the controller is further configured to select an indoor unit that meets a preset standard among the indoor units in heating mode as a first target indoor unit, including: Obtain the downtime of the indoor units that have stopped operating in multiple heating states, and select the indoor unit with the longest downtime as the first target indoor unit; If multiple indoor units that have stopped operating in heating mode have the same downtime, the indoor unit with the largest capacity will be selected as the first target indoor unit. If the downtime and capacity are the same, the indoor unit with the smallest address code is selected as the first target indoor unit.

[0018] In the above technical solution, the first target indoor unit is selected according to the priority rule of "longest heating shutdown time → largest capacity → smallest address code". This prioritizes the indoor unit with the largest refrigerant storage and the lowest probability of the user restarting the unit to perform the refrigerant release action. This ensures sufficient refrigerant release and the most obvious adjustment effect in a single operation, without interfering with the user's normal use. This improves refrigerant regulation efficiency and system response speed, while ensuring stable and shock-free control, thus enhancing the overall practicality and reliability of the solution.

[0019] In some embodiments, the controller is further configured to determine whether the system operating characteristic parameters meet preset trigger conditions; if so, to obtain the refrigerant control strategy corresponding to the refrigerant management mode, and further includes: When the control starts the second refrigerant management mode, the refrigerant high pressure value of the outdoor unit is obtained from the system operating characteristic parameters; Determine whether the refrigerant high pressure value is not less than the preset high pressure upper limit threshold; if so, then run the second refrigerant control strategy.

[0020] In the above technical solution, under the second refrigerant management mode, the real-time refrigerant high-pressure value of the system is used as the trigger condition. This allows for direct and rapid identification of high-pressure risks caused by excessive refrigerant, accurate judgment of the system's impending high-pressure protection threshold, and timely activation of the second refrigerant control strategy. This proactive intervention in high-pressure management effectively prevents system shutdowns and equipment damage due to high-pressure over-limit triggering of protection mechanisms, improves system operational safety, and extends the service life of the compressor and piping components.

[0021] In some embodiments, the controller is further configured to control the opening degrees of the first electronic expansion valve, the second electronic expansion valve, and the third electronic expansion valve based on the refrigerant control strategy to adjust the refrigerant circulation volume in the refrigerant pipeline, including: When the second refrigerant control strategy is running, the indoor unit that meets the preset standard in the heating state is selected as the second target indoor unit; Control the opening of the first electronic expansion valve corresponding to the second target indoor unit; The system controls the opening of the second electronic expansion valve connected to the second target indoor unit and the closing of the third electronic expansion valve connected to the second target indoor unit.

[0022] In the above technical solution, under the second refrigerant control strategy, by selecting the second target indoor unit and executing the control actions of opening the first electronic expansion valve, opening the second electronic expansion valve, and closing the third electronic expansion valve, the target indoor unit can be forcibly switched from the low-pressure side state to the high-pressure side condenser, enabling it to have the capacity to store a large amount of refrigerant. This allows it to quickly absorb excess refrigerant in the system, reduce the total amount of circulating refrigerant, alleviate the high-pressure accumulation trend, quickly and steadily reduce the system high pressure, eliminate the high-pressure alarm hazard, and ensure that the system can still operate continuously and stably under extreme load changes.

[0023] In some embodiments, the controller is further configured to select an indoor unit that meets a preset standard among the indoor units in heating mode as a second target indoor unit, including: Obtain the downtime of the indoor unit that is shut down in multiple cooling states, and select the indoor unit with the longest downtime as the second target indoor unit; If multiple indoor units that are shut down in cooling mode have the same shutdown time, the indoor unit with the largest capacity will be selected as the second target indoor unit. If the downtime and capacity are the same, the indoor unit with the smallest address code is selected as the second target indoor unit.

[0024] In the above technical solution, the second target indoor unit is selected according to the priority of "longest cooling shutdown time → largest capacity → smallest address code". By making full use of the structural characteristics of the indoor unit heat exchanger, the indoor unit with large heat exchange volume, long standby time and no impact on user use can be selected first to undertake the refrigerant storage task. This makes the high pressure relief effect most significant, the regulation efficiency highest, maximizes the refrigerant storage capacity, quickly balances the system pressure, improves the stability and effectiveness of high pressure control, and does not affect the normal functional output of the system.

[0025] In some embodiments, the controller is further configured to: According to a preset cycle, the system performs a judgment on the capacity ratio of the indoor unit on the cooling side and a judgment on whether the system operating characteristic parameters meet the preset trigger conditions. Furthermore, within each preset cycle, the opening degree of the first electronic expansion valve, the second electronic expansion valve, and the third electronic expansion valve corresponding to only one indoor unit is adjusted.

[0026] In the above technical solution, capacity percentage judgment and trigger condition judgment are performed cyclically according to a preset cycle, and valve adjustment is performed on only one indoor unit in each cycle. This avoids drastic fluctuations in refrigerant flow and system pressure caused by multiple indoor units switching modes simultaneously, preventing risks such as liquid slugging and pressure oscillation. This achieves stable and gradual refrigerant regulation, ensuring effective troubleshooting while maximizing system smoothness, protecting core components such as compressors and valves, and improving the long-term reliability and durability of the system.

[0027] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the connection of an air conditioning system according to an embodiment of this application; Figure 2 This is a schematic diagram of the overall refrigerant management process of an air conditioning system according to an embodiment of this application; Figure 3 This is a schematic diagram of the process for determining the outdoor unit's condenser operating mode according to an embodiment of this application; Figure 4 This is a schematic diagram of the process for determining the first refrigerant management mode according to an embodiment of this application; Figure 5 This is a schematic diagram of the triggering and judgment process of the first refrigerant control strategy according to an embodiment of this application; Figure 6 This is a schematic diagram of the execution flow of the first refrigerant control strategy according to an embodiment of this application; Figure 7 This is a schematic diagram of the process for determining the outdoor unit's evaporator operating mode according to an embodiment of this application; Figure 8 This is a schematic diagram of the triggering and judgment process of the second refrigerant control strategy according to an embodiment of this application; Figure 9 This is a schematic diagram of the second refrigerant management mode trigger execution process according to an embodiment of this application; Figure 10 This is a schematic diagram of the execution flow of the second refrigerant control strategy according to an embodiment of this application.

[0029] Figure label: 1. Outdoor unit; 2. Indoor unit; 3. Water module; 4. Switching device; 21. Indoor heat exchanger; 22. First electronic expansion valve; 41. Second electronic expansion valve; 42. Third electronic expansion valve. Detailed Implementation

[0030] Typical embodiments embodying the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various variations in different embodiments without departing from the scope of the present invention, and the descriptions and illustrations herein are for illustrative purposes only and not intended to limit the present invention.

[0031] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0032] Multi-split air conditioning systems, with their flexible unit configurations and high operational efficiency, have been widely used in various building scenarios. As user needs diversify, multi-split systems not only need to provide conventional cooling and heating functions but also expanded capabilities such as condensate heat recovery for hot water production. Three-pipe multi-split systems emerged to meet this demand. By adding a switching device, they overcome the limitation of traditional models that cannot simultaneously cool or heat, allowing different indoor units to operate in cooling or heating modes as needed. This greatly improves operational flexibility and better adapts to the varying cooling and heating requirements of different areas within the same space.

[0033] However, when the ratio of indoor units operating in cooling and heating modes is severely imbalanced, there will be a significant problem of uneven refrigerant distribution. For example, if there are fewer indoor units operating in cooling mode and more indoor units shut down in heating mode, a large amount of refrigerant will remain in the pipes and internal components of the indoor units shut down in heating mode. This will cause the operating indoor units to experience problems such as reduced cooling effect and decreased energy efficiency due to insufficient refrigerant supply.

[0034] In existing technologies, the main solutions to refrigerant distribution imbalance are increasing compressor frequency to increase refrigerant output or adding refrigerant recovery loops and pumps to draw refrigerant retained in the shut-down indoor units back into the system's main circulation. However, these methods still have significant drawbacks: First, the adjustment precision is insufficient. Existing solutions are mostly passive compensation-based adjustments, and when the indoor unit's operating mode, number of starts / stops, and cooling / heating load ratio fluctuate frequently, the control response is lagging, making it difficult to achieve rapid and accurate dynamic balance of the refrigerant. Second, system energy consumption increases significantly. Some solutions require additional driving of the recovery pump or long-term increase in compressor operating frequency, which not only increases overall energy consumption but also exacerbates wear and tear on core components and shortens equipment lifespan. Third, the system structure becomes more complex. Adding a large number of recovery pumps and pipelines increases manufacturing costs, increases the probability of failure, and increases the difficulty of later installation and maintenance. Therefore, existing technologies are poorly adaptable to complex operating conditions such as moderate cooling / heating load imbalance and frequent start / stop of indoor units, making it difficult to simultaneously achieve both refrigerant distribution precision and system operating efficiency.

[0035] To address the aforementioned technical problems, this application discloses an air conditioning system that acquires the operating status, operating mode, and system operating characteristic parameters of the indoor heat exchanger and water module, and determines the operating mode of the outdoor unit based on these parameters. When the water module and part of the indoor heat exchanger stop operating, the controller determines the capacity percentage of the indoor units on the cooling side. Based on the operating mode of the outdoor unit and the comparison between the capacity percentage of the indoor units on the cooling side and a preset threshold, the controller determines the refrigerant management mode, with each mode corresponding to a refrigerant control strategy. When the system operating characteristic parameters meet preset trigger conditions, the controller acquires the corresponding refrigerant control strategy and controls the opening of the first, second, and third electronic expansion valves based on this strategy to adjust the refrigerant circulation volume in the refrigerant pipeline, thereby solving the problem of abnormal refrigerant distribution.

[0036] In this application, reference is made to Figure 1 The air conditioning system includes outdoor units and indoor units. The indoor units consist of multiple indoor units and at least one water module, connected to the outdoor units via a switching device. The outdoor units are configured to compress and exchange the refrigerant. The outdoor units are the main power and heat exchange units of the air conditioning system, responsible for the compression, condensation, or evaporation of the refrigerant. Each indoor unit contains an indoor heat exchanger 21 for heat exchange within the indoor space to achieve cooling or heating functions. Each indoor heat exchanger 21 is connected to a corresponding first electronic expansion valve 22, which can be in the form of a capillary tube or a thermostatic expansion valve. Its function is to throttle and reduce the pressure of the refrigerant entering the indoor heat exchanger 21, thereby regulating the refrigerant flow rate and controlling its evaporation or condensation process. The water module, as a special heat exchange unit, achieves heat transfer through water, enabling cooling or heating of the water body. Refrigerant piping connects these main components, forming a refrigerant circulation loop.

[0037] Reference Figure 1 The switching device includes a second electronic expansion valve 41 and a third electronic expansion valve 42, which manage and balance the refrigerant quantity in the system by adjusting the refrigerant passage under specific operating conditions. Both electronic expansion valves are connected to the indoor unit via refrigerant piping. Specifically, the second electronic expansion valve 41 is connected to the outdoor unit 1 via a high-pressure gas pipe in the refrigerant piping, while the third electronic expansion valve 42 is connected to the outdoor unit 1 via a low-pressure gas pipe in the refrigerant piping. These two electronic expansion valves can be configured as bypass valves to introduce or discharge refrigerant from the high-pressure side or the low-pressure side to a certain indoor heat exchanger 21 under specific operating conditions, thereby regulating the refrigerant state or stored quantity in that indoor heat exchanger 21.

[0038] In this application, reference is made to Figure 1 and Figure 2It also has a controller, which is configured as follows: S110. Obtain the operating conditions and system operating characteristic parameters of multiple indoor units and water modules 3, including the evaporative superheat of the indoor unit, the opening degree of the first electronic expansion valve, and the refrigerant high pressure value of the outdoor unit.

[0039] The operating status can include detecting whether each indoor heat exchanger 21 is in an active or shutdown state. This can be determined by detecting parameters such as the temperature and pressure at the inlet and outlet of the indoor heat exchanger 21, and whether each indoor heat exchanger 21 is operating in cooling or heating mode. Alternatively, it can be determined by receiving user operation commands or system scheduling signals. System operating characteristic parameters, such as system high pressure, low pressure, superheat, and subcooling, can be collected in real time by installing corresponding pressure and temperature sensors on the refrigerant pipeline.

[0040] S120. Based on the operating conditions of multiple indoor units and water modules 3, determine the operating mode of outdoor unit 1.

[0041] Specifically, the controller can determine whether the outdoor unit 1 operates as a condenser or an evaporator based on the overall tendency of the cooling or heating modes of all operating indoor heat exchangers 21 and water modules 3 in the system. For example, when most or all operating indoor heat exchangers 21 and water modules 3 are in cooling mode, the outdoor unit 1 is usually identified as operating as a condenser; conversely, when most or all operating indoor heat exchangers 21 and water modules 3 are in heating mode, the outdoor unit 1 is identified as operating as an evaporator.

[0042] S130. When water module 3 and some indoor units stop running, determine the capacity ratio of the indoor units on the cooling side.

[0043] For example, when calculating the capacity ratio of the indoor units on the cooling side, the controller pre-stores the rated capacity information of each indoor heat exchanger 21 and water module 3. During operation, the controller identifies all indoor heat exchangers 21 currently in cooling mode, accumulates their rated capacities, and then obtains the cumulative capacity of the indoor heat exchangers 21 in the off state. The controller adds the rated capacity of the indoor heat exchangers 21 in cooling mode to the cumulative capacity of the indoor heat exchangers 21 in the off state to obtain a cumulative value. Then, the cumulative value is divided by the total rated capacity of all indoor heat exchangers 21 (including water module 3) to obtain the capacity ratio of the indoor units on the cooling side.

[0044] S140. The refrigerant management mode is determined based on the working mode of outdoor unit 1 and the comparison relationship between the capacity ratio of indoor units on the cooling side and the preset threshold. Different refrigerant management modes are configured with corresponding refrigerant control strategies.

[0045] For example, multiple capacity thresholds can be preset, such as a first threshold and a second threshold. When outdoor unit 1 operates as a condenser, if the proportion of the indoor unit capacity on the cooling side is lower than the first threshold, it may enter the first refrigerant management mode; when outdoor unit 1 operates as an evaporator, if the proportion of the indoor unit capacity on the cooling side is higher than the second threshold, it may enter the second refrigerant management mode. Each refrigerant management mode has a corresponding refrigerant control strategy preset.

[0046] S150. Determine whether the system operating characteristic parameters meet the preset trigger conditions. If so, obtain the refrigerant control strategy corresponding to the refrigerant management mode, and control the opening of the first electronic expansion valve 22, the second electronic expansion valve 41 and the third electronic expansion valve 42 based on the refrigerant control strategy to adjust the refrigerant circulation volume in the refrigerant pipeline.

[0047] Preset trigger conditions may include abnormal system high pressure, expansion valve opening, or abnormal evaporative superheat or condensing subcooling of a certain indoor heat exchanger 21. The controller continuously monitors these system operating characteristic parameters, and once the preset trigger conditions are met, the refrigerant management process is triggered. Once triggered, the controller retrieves the corresponding refrigerant control strategy from the pre-stored strategy library according to the currently determined refrigerant management mode. The controller then sends control signals to the corresponding first electronic expansion valve 22, second electronic expansion valve 41, and third electronic expansion valve 42 according to the strategy, adjusting their opening degrees. For example, the strategy may instruct the closure of a first electronic expansion valve 22 to stop the refrigerant circulation of that indoor heat exchanger 21, or the opening of a second electronic expansion valve 41 to introduce high-pressure refrigerant into a shut-down indoor heat exchanger 21 for storage, or the opening of a third electronic expansion valve 42 to discharge low-pressure refrigerant from a shut-down indoor heat exchanger 21, thereby achieving effective redistribution and balance of the system refrigerant and optimizing the operation of the entire air conditioning system.

[0048] In this application, the controller can acquire the operating status, operating mode, and system operating characteristic parameters of the indoor heat exchanger 21 and water module 3 in real time, accurately identify the system load distribution and refrigerant distribution status, and automatically match the corresponding refrigerant management mode based on the working mode of the outdoor unit 1 and the capacity ratio of the indoor unit on the cooling side. When the preset trigger conditions are met, a precise refrigerant control strategy is executed. The controller can coordinate the adjustment of the first electronic expansion valve 22, the second electronic expansion valve 41, and the third electronic expansion valve 42 according to the preset refrigerant control strategy, thereby actively adjusting the refrigerant circulation volume in the refrigerant pipeline, dynamically balancing the refrigerant circulation volume, effectively solving the problem of abnormal refrigerant distribution caused by the imbalance of cooling and heating load ratio, avoiding faults such as poor cooling effect, excessive exhaust temperature, and system high pressure alarm, significantly improving the operating stability, reliability, and environmental adaptability of the air conditioning system, while ensuring that the user experience is not affected.

[0049] In this application, reference is made to Figure 1 and Figure 2 The controller is also configured to, in step S120, determine the operating mode of the outdoor unit 1 based on the operating conditions of the multiple indoor heat exchangers 21 and the water module 3, including: S121. When the initial heating demand of the system is greater than the cooling demand, and the outdoor heat exchanger of outdoor unit 1 is running as an evaporator, when all indoor units and water modules 3 corresponding to the heating state are shut down, and only the indoor units in the cooling state are running, the outdoor heat exchanger switches to condenser operation.

[0050] Specifically, in the initial stage, the number of indoor units in heating mode is greater than the number in cooling mode, and the system's heating demand is greater than its cooling demand. Therefore, outdoor unit 1 operates as an evaporator. At a certain moment, the controller detects that all indoor heat exchangers 21 in heating mode and water modules 3 in heating mode have stopped operating, while only indoor heat exchangers 21 in cooling mode are running. This means that the main load of the entire air conditioning system is currently cooling demand, and the system's cooling demand is greater than its heating demand. In the cooling cycle, the main function of outdoor unit 1 is to release the heat absorbed from the indoor environment to the outdoor environment. At this time, the refrigerant inside the outdoor heat exchanger releases heat and condenses, thus operating as a condenser. This judgment method ensures that the functional positioning of outdoor unit 1 is accurate in pure cooling mode, providing a correct foundation for subsequent refrigerant management and control.

[0051] S122. When the initial cooling demand of the system is greater than the heating demand, and the outdoor heat exchanger is running as a condenser, when all indoor units and water modules 3 corresponding to the cooling state are shut down, and only the indoor units in the heating state are running, the outdoor heat exchanger switches to evaporator operation.

[0052] Initially, the number of indoor units in cooling mode exceeds the number in heating mode, and the system's cooling demand exceeds its heating demand. Therefore, outdoor unit 1 operates as a condenser. At a certain moment, when the controller detects that all indoor heat exchangers 21 in cooling mode and water modules 3 in cooling mode have stopped operating, and only indoor heat exchangers 21 in heating mode are running, this means that the primary load of the entire air conditioning system is currently the heating demand. In the heating cycle, the main function of outdoor unit 1 is to absorb heat from the outdoor environment and transfer it to the indoor unit. At this time, the refrigerant inside the outdoor heat exchanger absorbs heat and evaporates, thus operating as an evaporator. This judgment method ensures that the functional positioning of outdoor unit 1 is accurate in pure heating mode, providing a correct foundation for subsequent refrigerant management and control.

[0053] In actual operation, the system may have multiple operating modes (such as cooling, heating, partial shutdown, etc.) and the combined operation of indoor heat exchanger 21 and water module 3 is complex. If the specific conditions for outdoor unit 1 to operate as a condenser or evaporator are not clearly defined, the controller may not accurately judge the working mode of outdoor unit 1, which will affect the determination of the subsequent refrigerant management mode and the execution of the refrigerant control strategy, resulting in low system operating efficiency or unstable control.

[0054] In this application, the controller can accurately determine whether the outdoor heat exchanger should be in condenser mode or evaporator mode based on the cooling and heating operation status of the indoor heat exchanger 21 and the water module 3. This enables accurate identification and mode locking of the system's operating conditions, avoiding refrigerant regulation logic confusion due to mode misjudgment. It ensures a high degree of matching between the refrigerant control strategy and the actual system operating status, providing a reliable and accurate basis for subsequent refrigerant management mode determination and refrigerant circulation adjustment. This enhances the rigor and effectiveness of the overall control logic, ensuring stable switching and safe operation of the system under different operating conditions. For example, when the system is in pure cooling mode, the outdoor unit 1 is accurately identified as a condenser, and the controller can specifically adopt a refrigerant control strategy suitable for condenser operation, optimizing refrigerant flow and pressure to improve cooling efficiency. Conversely, when the system is in pure heating mode, the outdoor unit 1 is accurately identified as an evaporator, and the controller can adopt a refrigerant control strategy suitable for evaporator operation, ensuring sufficient refrigerant evaporation and improving heating effect. This not only helps improve the overall operating efficiency and stability of the air conditioning system, but also effectively avoids unnecessary energy consumption and component wear caused by misjudgment, thus extending the service life of the equipment.

[0055] In this application, reference is made to Figure 1 , Figure 3 and Figure 7 The controller is also configured to: Step S140, determine the refrigerant management mode based on the comparison between the operating mode of outdoor unit 1 and the capacity ratio of the indoor unit on the cooling side and a preset threshold, including: S141. When the outdoor heat exchanger is running as a condenser, determine whether the capacity ratio of the indoor unit on the cooling side is not greater than the first preset threshold. If so, control the start of the first refrigerant management mode.

[0056] For example, refer to Figure 1The air conditioning system is a combination structure consisting of one outdoor unit linked to three water modules 3 and four indoor units. The water modules 3 can provide hot water year-round. The indoor units 2 switch between cooling and heating modes via a matching switching device 4. The switching device 4 operates by alternating the actions of the second electronic expansion valve 41 and the third electronic expansion valve 42: when the indoor heat exchanger 21 is heating, the second electronic expansion valve 41 is open and the third electronic expansion valve 42 is closed; when the indoor heat exchanger 21 is cooling, the third electronic expansion valve 42 is open and the second electronic expansion valve 41 is closed.

[0057] During initial system operation, water modules 31#, 2#, and 3#, and indoor units 4#, 5#, and 6# are all in heating mode, while indoor unit 7# is in cooling mode. At this time, the system's heating demand exceeds its cooling demand, and the outdoor unit's heat exchanger operates as an evaporator. When all water modules 31#, 2#, and 3#, and indoor units 4#, 5#, and 6# are shut down, leaving only indoor unit 7# operating in cooling mode, the system's heating demand drops to zero, and the cooling demand exceeds the heating demand. The outdoor unit's heat exchanger then switches to condenser operation.

[0058] Because water modules 31#, 2#, and 3#, and indoor units 4#, 5#, and 6# remain in the heating off state, to prevent compressor lubricant buildup and potential damage due to insufficient lubrication, the electronic expansion valve EVW of water module 3 and the first electronic expansion valve 22 connected to indoor heat exchanger 21 are both kept slightly open. At this time, water modules 31#, 2#, and 3#, indoor units 4#, 5#, and 6#, and the outdoor heat exchanger all operate as condensers, storing a large amount of refrigerant. This results in insufficient refrigerant participating in the evaporation of indoor unit 7#, leading to a decrease in cooling efficiency. Simultaneously, due to the reduced refrigerant volume, the evaporative superheat of the indoor unit increases, causing the compressor suction superheat to rise accordingly. This can easily lead to excessively high compressor discharge temperature, affecting system reliability.

[0059] Therefore, to resolve the operational malfunctions caused by insufficient refrigerant, the controller determines whether the capacity ratio of the indoor unit on the cooling side is not greater than a first preset threshold, where the first preset threshold can be 10%. If so, the first refrigerant management mode is activated and the corresponding refrigerant control strategy is executed, switching the operating mode of the selected indoor unit heat exchanger in the heating off state. After the control is completed, the heat exchanger of this indoor unit will switch from a condenser to an evaporator, and the high-pressure liquid refrigerant stored inside will be drawn back to the gas-liquid separator and replenished into the system refrigerant circulation. This effectively increases the amount of refrigerant circulating in the cooling evaporation, thereby significantly improving the heat exchange effect of the indoor unit in cooling operation, reducing the evaporation superheat of the indoor unit and the compressor exhaust temperature, avoiding the cooling capacity reduction and abnormal temperature rise of the unit caused by insufficient refrigerant, and ensuring the stable and reliable operation of the system.

[0060] S142. When the outdoor heat exchanger is running as an evaporator, determine whether the capacity ratio of the indoor unit on the cooling side is not less than the second preset threshold. If so, run the second refrigerant management mode.

[0061] Reference Figure 1 During initial system operation, water modules 31#, 2#, and 3#, as well as indoor units 4#, 5#, and 6#, are all in cooling mode, while indoor unit 7# is in heating mode. At this time, the system's cooling demand exceeds its heating demand, and the outdoor unit's heat exchanger operates as a condenser. When all water modules 31#, 2#, and 3#, and indoor units 4#, 5#, and 6# are shut down, leaving only indoor unit 7# operating in heating mode, the system's cooling demand drops to zero, and the heating demand exceeds the cooling demand. The outdoor unit's heat exchanger then switches to evaporator operation.

[0062] Because water modules 31#, 2#, and 3#, and indoor units 4#, 5#, and 6# remain in the cooling off state, the electronic expansion valve EVW of water module 3 and the first electronic expansion valve 22 connected to indoor heat exchanger 21 are both in the fully closed state. At this time, the outdoor unit heat exchanger operates as an evaporator. Both water module 3 and the indoor unit heat exchanger, in their off-state state, are located on the low-pressure side, and the amount of refrigerant that can be stored is very limited. Only indoor unit 7# acts as a condenser to handle refrigerant condensation, which can easily lead to a large accumulation of refrigerant at this indoor unit, causing a rapid increase in system high pressure, triggering a high-pressure protection fault, and affecting the normal operation of the system.

[0063] Therefore, when the outdoor heat exchanger operates as an evaporator, if the capacity ratio of the indoor units on the cooling side is not less than the second preset threshold (where the second preset threshold can be 90%), it indicates that only one or very few indoor units in the system are undertaking heating and condensing functions. A large number of indoor heat exchangers 21 and water modules 3, which are shut down for cooling, are on the low-pressure side and cannot store refrigerant. This easily leads to excessive accumulation of refrigerant in the system, causing a rapid rise in high pressure and triggering a high-pressure protection fault. To solve the high-pressure anomaly caused by excessive refrigerant accumulation, the controller activates the second refrigerant management mode and executes the corresponding refrigerant control strategy. This switches the operating mode of the selected indoor unit heat exchanger in the cooling-off state. After the control is completed, this indoor unit heat exchanger switches from the low-pressure side to the high-pressure side, i.e., switches to a condenser, which can store a certain amount of refrigerant. This indirectly reduces the amount of refrigerant circulating in the system, thereby alleviating the refrigerant accumulation in indoor unit #7, preventing excessively high pressure, and ensuring the system continues to operate stably and safely under extreme load conditions.

[0064] In this solution, based on the operating mode of the outdoor heat exchanger and the comparison between the indoor unit capacity ratio on the cooling side and the first and second preset thresholds, either the first or second refrigerant management mode is activated for different scenarios. This enables the classification, identification, and refined control of abnormal refrigerant conditions. It can address both "insufficient refrigerant" and "excessive refrigerant and high pressure" fault conditions, avoiding the limitations of a single adjustment logic that cannot adapt to complex heating and cooling imbalance scenarios. This significantly improves the system's adaptability to extreme load changes, making refrigerant adjustment more targeted, timely, and rational, thereby improving the overall system operating efficiency and enhancing the air conditioning system's performance and energy-saving effects.

[0065] In some embodiments, the controller is further configured to determine whether the system operating characteristic parameters meet preset trigger conditions; if so, to obtain the refrigerant control strategy corresponding to the refrigerant management mode, including: when the controller starts the first refrigerant management mode, obtaining the opening degree of the first electronic expansion valve 22 corresponding to the indoor unit in the cooling state in the system operating characteristic parameters, and determining whether the opening degree of the first electronic expansion valve 22 is not less than a preset opening degree threshold; if so, obtaining the evaporative superheat of the indoor unit in the cooling state in the system operating characteristic parameters, and determining whether the evaporative superheat is not less than a preset superheat threshold; if the evaporative superheat is not less than the preset superheat threshold, then running the first refrigerant control strategy.

[0066] For example, refer to Figure 1 , Figure 4 and Figure 5 The controller actively acquires the real-time opening degree of the first electronic expansion valve 22 corresponding to all indoor heat exchangers 21 in cooling mode. Then, it determines whether the minimum opening value of all first electronic expansion valves 22 is not less than a preset opening threshold, which can be set to 50% to indicate whether the first electronic expansion valve 22 is already in a relatively large open state. When the opening degree of the first electronic expansion valve 22 reaches or exceeds this threshold, it may mean that the indoor heat exchanger 21 is operating at a high load or the refrigerant flow demand is high. In this case, the system may have a risk of insufficient refrigerant, requiring further evaluation. The controller then further acquires the evaporative superheat of the cooling indoor heat exchanger 21 from the system operating characteristic parameters. The evaporative superheat can be the difference between the refrigerant temperature at the outlet of the indoor unit heat exchanger and the refrigerant temperature at the inlet of the indoor unit heat exchanger. The controller determines whether this evaporative superheat is not less than a preset superheat threshold, which can be set to 5. This preset superheat threshold is the minimum superheat required for normal system operation. It is typically used to ensure complete vaporization of the refrigerant at the evaporator outlet, preventing liquid slugging into the compressor, while also maintaining a certain level of heat exchange efficiency. When the evaporation superheat reaches or exceeds this threshold, it indicates that the refrigerant in the evaporator may be overheating, signaling insufficient refrigerant or improper refrigerant distribution in the system. Appropriate refrigerant control strategies need to be activated for intervention.

[0067] Therefore, when all the above conditions (the opening degree of the first electronic expansion valve 22 is not less than the preset opening threshold and the evaporation superheat is not less than the preset superheat threshold) are met, the controller will trigger and execute the first refrigerant control strategy. The first refrigerant control strategy is a series of control actions designed for specific refrigerant management modes to solve the problems of uneven refrigerant distribution or insufficient refrigerant quantity. It aims to improve system operating efficiency and stability by adjusting the opening degree of relevant expansion valves and optimizing the refrigerant circulation.

[0068] In this application, under the first refrigerant management mode, by using dual conditions—the opening degree of the first electronic expansion valve 22 and the evaporation superheat of the heat exchanger 21 in the refrigeration chamber—the system can accurately and reliably identify insufficient refrigerant circulation, effectively avoiding false triggering and misadjustment caused by parameter fluctuations. Combining valve position characteristics and temperature characteristics as dual indicators improves the accuracy of refrigerant anomaly identification, providing a reliable basis for the execution of refrigerant control strategies. This ensures that refrigerant replenishment is initiated only when truly needed, enhancing system control stability and reducing pressure fluctuations and increased energy consumption caused by ineffective adjustments.

[0069] In some embodiments, the controller is further configured to control the opening of the first electronic expansion valve 22, the second electronic expansion valve 41, and the third electronic expansion valve 42 based on a refrigerant control strategy to adjust the refrigerant circulation volume in the refrigerant pipeline, including: when the first refrigerant control strategy is running, selecting an indoor unit that meets a preset standard in the heating state as the first target indoor unit; controlling the closing of the first electronic expansion valve 22 corresponding to the first target indoor unit; controlling the closing of the second electronic expansion valve 41 connected to the first target indoor unit, and opening the third electronic expansion valve 42 connected to the first target indoor unit.

[0070] Reference Figure 1 , Figure 6When the air conditioning system operates under the first refrigerant control strategy, the controller selects an indoor unit as the first target indoor unit from those currently in heating mode and off, based on a series of preset criteria. The controller sends a command to the first electronic expansion valve 22 corresponding to this indoor unit, causing it to close completely. This closure effectively cuts off the refrigerant's path from the main refrigerant line into the indoor unit, preventing unintended refrigerant inflow or outflow, thus isolating the indoor unit from the main refrigerant circulation loop and creating conditions for subsequent refrigerant management operations. Simultaneously, the controller further operates the second electronic expansion valve 41 and the third electronic expansion valve 42 connected to it. Closing the second electronic expansion valve 41 prevents high-pressure refrigerant gas from entering the indoor unit. Opening the third electronic expansion valve 42 provides a path to the low-pressure side for any refrigerant that may be present inside or near the indoor unit, treating the first target indoor unit as a temporary refrigerant treatment or bypass path, thereby achieving effective refrigerant management and redistribution.

[0071] Thus, under the first refrigerant control strategy, by selecting a first target indoor unit that meets the standard, and executing coordinated control by closing the first electronic expansion valve 22, closing the second electronic expansion valve 41, and opening the third electronic expansion valve 42, the heat exchanger of the target indoor unit can be forcibly switched from the high-pressure side condenser to the low-pressure side evaporator, quickly releasing the large amount of refrigerant stored inside and replenishing it to the system circulation. This can directly and efficiently increase the refrigerant supply to the indoor unit operating in cooling mode, rapidly improving problems such as poor cooling effect, high evaporation superheat, and high exhaust temperature caused by insufficient refrigerant, restoring the system's normal heat exchange capacity, and improving the user's cooling experience.

[0072] In some embodiments, the controller is further configured to select an indoor unit that meets a preset standard among the indoor units in heating mode as the first target indoor unit, including: obtaining the downtime of multiple indoor units that are shut down in heating mode, and selecting the indoor unit with the longest downtime as the first target indoor unit; if the downtime of multiple indoor units that are shut down in heating mode is the same, then selecting the indoor unit with the largest capacity as the first target indoor unit; if both the downtime and capacity are the same, then selecting the indoor unit with the smallest address code as the first target indoor unit.

[0073] Specifically, refer to Figure 1When selecting the first target indoor unit, the controller first obtains the downtime of multiple indoor units that are shut down in heating mode, and prioritizes the one with the longest downtime as the first target indoor unit. If the controller finds multiple indoor units with the same downtime, it further filters them based on their capacity, selecting the one with the largest capacity among those with the same downtime as the first target indoor unit. Selecting the largest capacity ensures greater adjustment margin or more significant adjustment effect when refrigerant volume needs to be managed by adjusting this indoor unit, thereby improving the efficiency and response speed of refrigerant management. If, after the above two-stage filtering, multiple indoor units with the same downtime and capacity remain shut down in heating mode, the controller uses the address code as the final determination criterion. The controller selects the indoor unit with the smallest address code as the first target indoor unit. For example, after the above two-stage screening, indoor units 4#, 5#, and 6# have the same downtime and capacity, so indoor unit 4# is selected as the first target indoor unit.

[0074] Thus, by selecting the first target indoor unit according to the priority rule of "longest heating shutdown time → largest capacity → smallest address code," the system can prioritize the indoor unit with the largest refrigerant storage and the lowest probability of the user restarting the unit to perform the refrigerant release action. This ensures sufficient refrigerant release and the most obvious adjustment effect in a single operation, without interfering with the user's normal use. This improves refrigerant regulation efficiency and system response speed, while ensuring stable and shock-free control, thereby enhancing the overall practicality and reliability of the solution.

[0075] In some embodiments, the controller is further configured to determine whether the system operating characteristic parameters meet the preset trigger conditions; if so, to obtain the refrigerant control strategy corresponding to the refrigerant management mode; and further to: when the controller starts the second refrigerant management mode, to obtain the refrigerant high pressure value of outdoor unit 1 in the system operating characteristic parameters; to determine whether the refrigerant high pressure value is not less than the preset high pressure upper limit threshold; if so, to run the second refrigerant control strategy.

[0076] Specifically, refer to Figure 1 , Figure 7 , Figure 8 and Figure 9When the controller determines that the system should enter the second refrigerant management mode based on the comparison between the operating mode of the air conditioning system and the capacity ratio of the indoor units on the cooling side, the controller will further perform a high-pressure risk assessment. The controller will obtain the refrigerant high-pressure value of outdoor unit 1 from the system operating characteristic parameters. The refrigerant high-pressure value of outdoor unit 1 is a key parameter reflecting the high-pressure side operating status of the air conditioning system. The controller obtains this value through a high-pressure sensor connected to the high-pressure pipeline of outdoor unit 1, which is the refrigerant high pressure on the compressor exhaust side or the outdoor heat exchanger inlet side. Then, the controller compares the real-time refrigerant high-pressure value with the preset high-pressure upper limit threshold to determine whether the system faces a high-pressure risk or has reached a critical state requiring intervention. When the refrigerant high-pressure value reaches or exceeds the preset high-pressure upper limit threshold, the second refrigerant control strategy is adopted. By adjusting the refrigerant circulation volume in the refrigerant pipeline, the system high pressure is reduced, and the system stable operation is restored. Specific control measures may include adjusting the opening of the first electronic expansion valve 22, the second electronic expansion valve 41, and the third electronic expansion valve 42 to optimize the refrigerant flow distribution, thereby effectively alleviating the high-pressure problem.

[0077] Thus, in the second refrigerant management mode, using the system's real-time refrigerant high-pressure value as a trigger condition, it is possible to directly and quickly identify the risk of excessive refrigerant leading to high pressure, accurately determine the dangerous state of the system approaching the high-pressure protection threshold, and promptly activate the second refrigerant control strategy. This allows for early intervention in high-pressure management, effectively preventing system shutdowns due to high-pressure over-limit triggering protection, equipment damage, and other issues, thereby improving system operational safety and extending the service life of the compressor and piping components.

[0078] In some embodiments, the controller is further configured to control the opening of the first electronic expansion valve 22, the second electronic expansion valve 41, and the third electronic expansion valve 42 based on a refrigerant control strategy to adjust the refrigerant circulation volume in the refrigerant pipeline, including: when the second refrigerant control strategy is running, selecting an indoor unit that meets a preset standard in the cooling state as the second target indoor unit; controlling the opening of the first electronic expansion valve 22 corresponding to the second target indoor unit; controlling the opening of the second electronic expansion valve 41 connected to the second target indoor unit, and closing the third electronic expansion valve 42 connected to the second target indoor unit.

[0079] Reference Figure 1 , Figure 9 and Figure 10When the system needs to implement a second refrigerant control strategy to cope with high-pressure conditions, the controller first selects one indoor unit from among the multiple indoor units currently in heating mode and off, according to preset standards, as the "second target indoor unit." It then controls the opening of the first electronic expansion valve 22 corresponding to this second target indoor unit, allowing more refrigerant to enter that unit. In heating mode, this helps increase the evaporation rate of the indoor unit, thereby affecting the high-pressure side pressure of the system. Then, it further controls the opening of the second electronic expansion valve 41 and the closing of the third electronic expansion valve 42. The second electronic expansion valve 41 is connected to the outdoor unit 1 via a high-pressure gas pipe in the refrigerant pipeline. Its opening provides an additional refrigerant flow path for the system; for example, it allows some high-pressure refrigerant to be regulated or diverted through this path, effectively alleviating system high pressure. Simultaneously, closing the third electronic expansion valve 42 ensures that the refrigerant flows along a preset path, avoiding unnecessary refrigerant short circuits or flow to the low-pressure side, thus maintaining the stability of system operation.

[0080] Thus, under the second refrigerant control strategy, by selecting the second target indoor unit and executing the control actions of opening the first electronic expansion valve 22, opening the second electronic expansion valve 41, and closing the third electronic expansion valve 42, the target indoor unit can be forcibly switched from the low-pressure side state to the high-pressure side condenser, enabling it to have the capacity to store a large amount of refrigerant. This allows it to quickly absorb excess refrigerant in the system, reduce the total amount of circulating refrigerant, alleviate the high-pressure accumulation trend, quickly and steadily reduce the system high pressure, eliminate the high-pressure alarm hazard, and ensure that the system can still operate continuously and stably under extreme load changes.

[0081] In some embodiments, the controller is further configured to select an indoor unit that meets a preset standard among the indoor units in heating mode as the second target indoor unit, including: obtaining the downtime of multiple indoor units that are shut down in cooling mode, and selecting the indoor unit with the longest downtime as the second target indoor unit; if the downtime of multiple indoor units that are shut down in cooling mode is the same, then selecting the indoor unit with the largest capacity as the second target indoor unit; if both the downtime and capacity are the same, then selecting the indoor unit with the smallest address code as the second target indoor unit.

[0082] Reference Figure 1First, the controller acquires the downtime of multiple indoor units that have stopped operating in cooling mode, and selects the indoor unit with the longest downtime as the second target indoor unit. By prioritizing downtime, frequent adjustments to indoor units that are currently running or have just stopped can be avoided, thereby reducing potential interference with user comfort and helping to balance the lifespan of each indoor unit. If multiple indoor units that have stopped operating in cooling mode have the same downtime, the controller will further select the indoor unit with the largest capacity as the second target indoor unit. Indoor units with larger capacity usually have a larger heat exchange area and refrigerant handling capacity, so they can absorb or release refrigerant more effectively during refrigerant adjustment, thereby alleviating high-pressure problems in the system more quickly and improving the system's response speed and adjustment efficiency. If both the downtime and the capacity are the same, the controller selects the indoor unit with the smallest address code as the second target indoor unit, ensuring the uniqueness and stability of the system selection process.

[0083] Thus, by prioritizing the second target indoor unit according to the order of "longest cooling shutdown time → largest capacity → smallest address code", the structural characteristics of the indoor unit's heat exchanger can be fully utilized. This allows for the selection of indoor units with large heat exchange volume, long standby time, and no impact on user operation to undertake the refrigerant storage task. This results in the most significant high-pressure relief effect, the highest regulation efficiency, maximizes refrigerant storage capacity, quickly balances system pressure, and improves the stability and effectiveness of high-pressure control, while not affecting the normal functional output of the system.

[0084] In some embodiments, the controller is further configured to: perform a judgment on the capacity ratio of the indoor unit on the cooling side and a judgment on whether the system operating characteristic parameters meet the preset trigger conditions according to a preset cycle; and within each preset cycle, adjust the opening degree of the first electronic expansion valve 22, the second electronic expansion valve 41 and the third electronic expansion valve 42 corresponding to only one indoor unit.

[0085] Reference Figure 5 and Figure 9 The controller executes refrigerant management logic at a preset cycle. It periodically calculates and judges the capacity ratio of the indoor units on the cooling side, and checks whether the system's operating characteristic parameters meet preset trigger conditions, using a pre-defined time interval (i.e., the preset cycle). This helps avoid unnecessary computational burden and potential control disturbances caused by overly frequent detection and response in the control system. The preset cycle can be a fixed time value, such as executing every 1 second, 5 minutes, or 10 minutes, or it can be dynamically adjusted according to factors such as system load, operating mode, or ambient temperature to achieve a balance between response speed and system stability.

[0086] Within each preset cycle, the opening degree of the first electronic expansion valve 22, the second electronic expansion valve 41, and the third electronic expansion valve 42 corresponding to only one indoor unit is adjusted, effectively avoiding transient system shocks caused by simultaneous or near-simultaneous large-scale opening adjustments of multiple expansion valves. The controller can select the target indoor unit in ways including, but not limited to: according to a preset priority order (e.g., based on the indoor unit's downtime, capacity, or address code), or using a polling mechanism to ensure that each eligible indoor unit has a chance to be adjusted.

[0087] In this way, by cyclically performing capacity percentage and trigger condition checks according to a preset cycle, and adjusting the valves of only one indoor unit in each cycle, the system avoids drastic fluctuations in refrigerant flow and system pressure caused by multiple indoor units switching modes simultaneously, thus preventing risks such as liquid slugging and pressure oscillations. This achieves stable and gradual refrigerant regulation, ensuring effective troubleshooting while maximizing system smoothness, protecting core components such as the compressor and valves, and improving the long-term reliability and durability of the system.

[0088] Although the invention has been described with reference to several typical embodiments, it should be understood that the terminology used is descriptive and exemplary, and not restrictive. Since the invention can be embodied in many forms without departing from the spirit or essence of the invention, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims. Therefore, all variations and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. An air conditioning system, characterized in that, include: Outdoor unit; Indoor unit, including: Multiple indoor units, each of which is connected to a first electronic expansion valve, and the multiple first electronic expansion valves are connected to the outdoor unit through refrigerant pipelines; At least one water module, the water module being connected to the outdoor unit and the indoor unit via the refrigerant piping; The switching device includes a second electronic expansion valve and a third electronic expansion valve. Both the second electronic expansion valve and the third electronic expansion valve are connected to the indoor unit through refrigerant pipelines. The second electronic expansion valve is connected to the outdoor unit through a high-pressure gas pipe in the refrigerant pipelines, and the third electronic expansion valve is connected to the outdoor unit through a low-pressure gas pipe in the refrigerant pipelines. The controller, wherein the controller is configured to: The operating conditions and system operating characteristic parameters of multiple indoor units and water modules are obtained, wherein the system operating characteristic parameters include the evaporative superheat of the indoor unit, the opening degree of the first electronic expansion valve, and the refrigerant high pressure value of the outdoor unit. Based on the operating conditions of the multiple indoor units and the water module, the operating mode of the outdoor unit is determined; When the water module and part of the indoor units stop operating, the capacity ratio of the cooling-side indoor units is determined. The refrigerant management mode is determined based on the comparison between the working mode of the outdoor unit and the capacity ratio of the indoor unit on the cooling side and a preset threshold. Different refrigerant management modes are configured with corresponding refrigerant control strategies. Determine whether the system operating characteristic parameters meet the preset trigger conditions. If so, obtain the refrigerant control strategy corresponding to the refrigerant management mode, and control the opening degree of the first electronic expansion valve, the second electronic expansion valve and the third electronic expansion valve based on the refrigerant control strategy to adjust the refrigerant circulation volume in the refrigerant pipeline.

2. The air conditioning system according to claim 1, characterized in that, The controller is also configured to determine the operating mode of the outdoor unit based on the operating conditions of the multiple indoor units and the water module, including: When the initial heating demand of the system is greater than the cooling demand, and the outdoor heat exchanger of the outdoor unit is running as an evaporator, when all the indoor units and water modules corresponding to the heating state are shut down, and only the indoor units in the cooling state are running, the outdoor heat exchanger switches to condenser operation. When the initial cooling demand of the system is greater than the heating demand, and the outdoor heat exchanger is operating as a condenser, when all indoor units and water modules corresponding to the cooling state are shut down, and only the indoor units in the heating state are running, the outdoor heat exchanger switches to evaporator operation.

3. The air conditioning system according to claim 2, characterized in that, The controller is further configured to: determine a refrigerant management mode based on a comparison between the operating mode of the outdoor unit and the capacity ratio of the indoor unit on the cooling side and a preset threshold, including: When the outdoor heat exchanger is running as a condenser, it is determined whether the capacity ratio of the indoor unit on the cooling side is not greater than a first preset threshold. If so, the first refrigerant management mode is activated. When the outdoor heat exchanger is running as an evaporator, it is determined whether the capacity ratio of the indoor unit on the cooling side is not less than the second preset threshold. If so, the second refrigerant management mode is run.

4. The air conditioning system according to claim 3, characterized in that, The controller is further configured to determine whether the system operating characteristic parameters meet preset trigger conditions; if so, to obtain the refrigerant control strategy corresponding to the refrigerant management mode, including: When the first refrigerant management mode is activated, the opening degree of the first electronic expansion valve corresponding to the indoor unit in the cooling state is obtained from the system operation characteristic parameters, and it is determined whether the opening degree of the first electronic expansion valve is not less than the preset opening degree threshold. If so, then obtain the evaporative superheat of the indoor unit in the cooling state from the system operation characteristic parameters, and determine whether the evaporative superheat is not less than the preset superheat threshold. If the evaporation superheat is not less than the preset superheat threshold, then the first refrigerant control strategy is executed.

5. The air conditioning system according to claim 4, characterized in that, The controller is further configured to control the opening degrees of the first electronic expansion valve, the second electronic expansion valve, and the third electronic expansion valve based on the refrigerant control strategy, in order to regulate the refrigerant circulation volume in the refrigerant pipeline, including: When the first refrigerant control strategy is running, the indoor unit that meets the preset standard in the heating state is selected as the first target indoor unit; Control the closure of the first electronic expansion valve corresponding to the first target indoor unit; The control closes the second electronic expansion valve connected to the first target indoor unit and opens the third electronic expansion valve connected to the first target indoor unit.

6. The air conditioning system according to claim 5, characterized in that, The controller is further configured to select an indoor unit that meets a preset standard from the indoor units in heating mode as a first target indoor unit, including: Obtain the downtime of the indoor units that have stopped operating in multiple heating states, and select the indoor unit with the longest downtime as the first target indoor unit; If multiple indoor units that have stopped operating in heating mode have the same downtime, the indoor unit with the largest capacity will be selected as the first target indoor unit. If the downtime and capacity are the same, the indoor unit with the smallest address code is selected as the first target indoor unit.

7. The air conditioning system according to claim 3, characterized in that, The controller is further configured to determine whether the system operating characteristic parameters meet preset trigger conditions; if so, to obtain the refrigerant control strategy corresponding to the refrigerant management mode, and further includes: When the control starts the second refrigerant management mode, the refrigerant high pressure value of the outdoor unit is obtained from the system operating characteristic parameters; Determine whether the refrigerant high pressure value is not less than the preset high pressure upper limit threshold; if so, then run the second refrigerant control strategy.

8. The air conditioning system according to claim 7, characterized in that, The controller is further configured to control the opening degrees of the first electronic expansion valve, the second electronic expansion valve, and the third electronic expansion valve based on the refrigerant control strategy, in order to regulate the refrigerant circulation volume in the refrigerant pipeline, including: When the second refrigerant control strategy is running, the indoor unit that meets the preset standard in the heating state is selected as the second target indoor unit; Control the opening of the first electronic expansion valve corresponding to the second target indoor unit; The system controls the opening of the second electronic expansion valve connected to the second target indoor unit and the closing of the third electronic expansion valve connected to the second target indoor unit.

9. The air conditioning system according to claim 8, characterized in that, The controller is further configured to select an indoor unit that meets a preset standard from the indoor units in heating mode as a second target indoor unit, including: Obtain the downtime of the indoor unit that is shut down in multiple cooling states, and select the indoor unit with the longest downtime as the second target indoor unit; If multiple indoor units that are shut down in cooling mode have the same shutdown time, the indoor unit with the largest capacity will be selected as the second target indoor unit. If the downtime and capacity are the same, the indoor unit with the smallest address code is selected as the second target indoor unit.

10. The air conditioning system according to any one of claims 1-9, characterized in that, The controller is also configured to: According to a preset cycle, the system performs a judgment on the capacity ratio of the indoor unit on the cooling side and a judgment on whether the system operating characteristic parameters meet the preset trigger conditions. Furthermore, within each preset cycle, the opening degree of the first electronic expansion valve, the second electronic expansion valve, and the third electronic expansion valve corresponding to only one indoor unit is adjusted.

Images