Multi-split air conditioning system

Abstract

The invention discloses a multi-split air conditioning system, and belongs to the technical field of air conditioners. The multi-split air conditioning system comprises an outdoor unit provided with a compressor; the at least one indoor tail end is communicated with the outdoor unit through a pipeline; the control module is configured to determine the required evaporation temperature or the required condensation temperature of each indoor tail end in a preset period and determine the required evaporation pressure or the required condensation pressure corresponding to the required evaporation temperature or the required condensation temperature; and according to the refrigeration demand capacity and / or the heating demand capacity of the indoor tail end in the system, a circulating system of the air conditioning system is determined as a refrigeration main body or a heating main body, and the corresponding evaporation pressure or condensation pressure is selected as the target pressure of a compressor. According to the system, matching of the demand capacity and the output capacity can be better achieved, and the output compressor frequency is made to be matched with the demand optimal pressure.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air conditioning, in particular to a multi-connected air conditioning system. BACKGROUND

[0002] In the control of a conventional multi-connected air conditioning system, the operating frequency of a compressor is usually determined according to the temperature difference between the return air temperature and the set temperature. When there are multiple indoor units in the system, in order to ensure overall comfort requirements, the compressor often operates at the maximum required frequency to output the corresponding refrigeration or heating capacity.

[0003] However, in actual applications, there are scenarios in which process air conditioners (such as constant temperature and humidity air conditioners) and comfort air conditioners (such as civilian comfort air conditioners) are connected and operated in the same multi-connected air conditioning system. Due to the different environmental control objectives of these two types of terminals, there is a significant difference in their capacity requirements for the system, causing a serious mismatch between the system output capacity and the actual terminal demand capacity. For example, comfort air conditioners focus on rapid response and thermal comfort, so in the control strategy, a high target pressure value is usually set to drive the compressor to operate at a high frequency to achieve rapid refrigeration or heating. However, when the process air conditioner load is small or the temperature change requirement is slow, this high-frequency output will result in excess system output capacity, causing a large amount of invalid energy consumption.

[0004] In addition, the types of terminals in a multi-connected air conditioning system are diverse, and different types of terminals have large differences in heat exchange efficiency, set working conditions, return air / water temperature, etc., which further exacerbates the deviation between demand capacity and output capacity. The traditional control strategy cannot take into account the real operating state of all terminals, resulting in the inability of the entire system to achieve optimal energy efficiency operation under comprehensive load conditions. SUMMARY

[0005] The present application provides a multi-connected air conditioning system, comprising: an outdoor unit provided with a compressor; at least one indoor terminal in communication with the outdoor unit through a pipeline; a control module configured to: determine the refrigeration demand capacity of the indoor terminal according to the air enthalpy difference method , the heating demand capacity ; establish an output capacity calculation model of the terminal, determine the demand evaporation temperature or demand condensation temperature of each indoor terminal in a predetermined period using the output capacity calculation model of the terminal, and determine the demand evaporation pressure or demand condensation pressure corresponding to the demand evaporation temperature or demand condensation temperature; determine whether the circulating system of the air conditioning system is a refrigeration main body or a heating main body according to the refrigeration demand capacity and / or the heating demand capacity of the indoor terminal in the system; If the circulation system is the main heating body, the maximum required condensing pressure between the indoor terminals is selected If the circulation system is the main refrigeration body, the minimum required evaporating pressure between the indoor terminals is selected as the target pressure of the compressor.

[0006] Based on the above configuration, the air conditioning system of the present application evaluates the load demand of each indoor terminal in real time, including the refrigeration demand capacity and the heating demand capacity. On this basis, the system constructs an end output capacity calculation model to periodically predict the required evaporating temperature or the required condensing temperature of each indoor terminal, and further converts it into the required evaporating pressure or the required condensing pressure.

[0007] By comprehensively judging these pressure values, the system determines whether the current air conditioning circulation system should work in refrigeration mode or heating mode, and accordingly selects the minimum required evaporating pressure or the maximum required condensing pressure as the target pressure setting value of the compressor. This control logic ensures that the system prioritizes meeting the operating requirements of the most disadvantaged terminal (i.e., the terminal with the largest heat exchange demand), and on this basis, maximally reduces the suction and discharge pressure difference of the compressor, thereby reducing the power consumption of the compressor and improving the overall energy efficiency.

[0008] In the above embodiments, when the indoor terminal is a water terminal, the heating demand capacity of the present application is represented as the heating demand capacity .

[0009] In some embodiments, the control module uses a PID control method to adjust the frequency of the compressor, so that the real-time pressure of the compressor is equal to or close to the target pressure, achieving dynamic optimization control of the operating pressure and improving the operating energy efficiency of the whole machine.

[0010] Specifically, the control module calculates the deviation value of the real-time pressure and the set target pressure, and according to the size of the deviation (proportional term), the cumulative amount of the deviation over time (integral term) and the rate of change of the deviation (derivative term), outputs a control instruction to adjust the operating frequency of the compressor. Through continuous closed-loop feedback control, the operating frequency of the compressor is finely adjusted, so that its actual discharge pressure or suction pressure quickly approaches the pre-set target pressure, achieving dynamic stable control.

[0011] In some embodiments, the control module is configured with a demand capacity calculation period, and the above logic is executed according to the demand capacity calculation period to dynamically determine the target pressure of each demand capacity calculation period. By setting the demand capacity calculation period and achieving periodic dynamic evaluation, the system can quickly respond to changes in terminal load, improving the timeliness and accuracy of control.

[0012] In some embodiments, determining the required evaporation temperature or required condensation temperature of each indoor terminal within a preset cycle using a terminal output capacity calculation model further includes: Determine whether the indoor terminal operates in cooling or heating mode. Calculate the required heat exchange for each of the indoor terminals, the first... The heat exchange requirement of each indoor terminal is denoted as . ; If the indoor terminal is in cooling mode, the required evaporation temperature of the indoor terminal is calculated based on the total required heat exchange using the evaporation capacity calculation model in the terminal output capacity calculation model. If the indoor terminal is in heating mode, the required condensing temperature of the indoor terminal is calculated based on the total required heat exchange using the condensing capacity calculation model in the terminal output capacity calculation model.

[0013] This implementation method deeply integrates cooling / heating status identification, demand heat exchange calculation, and terminal capacity model, realizing a quantitative mapping between heat exchange capacity and operating temperature, thereby improving the rationality and accuracy of the system target temperature setting.

[0014] In some embodiments, the required heat exchange of the indoor terminal in heating mode is obtained by calculating the change in sensible heat of the indoor terminal; the required heat exchange of the indoor terminal in cooling mode is obtained by calculating the change in sensible heat of the indoor terminal. and latent heat change The result is obtained by adding the two together.

[0015] In some embodiments, the first The required evaporation temperature for each indoor terminal is calculated based on the following evaporation capacity calculation model:

[0016] in, , , , For the first The first, second, third, and fourth fitting parameters for each indoor terminal. For the first The heat exchange requirement of each indoor terminal For the first The effect coefficient of normalized superheat on capacity of each indoor terminal. For the first The return air temperature at each indoor terminal For the first The dew point temperature value of each indoor terminal.

[0017] Based on the aforementioned evaporation capacity calculation model, this embodiment establishes a functional mapping relationship between heat exchange demand and terminal operating conditions. This allows the calculation of the required evaporation temperature to no longer rely on static settings or empirical values, but rather on dynamic estimation based on real-time operating data and fitted parameters, resulting in high accuracy and adaptability. The model structure is clear, the physical meaning of the parameters is explicit, and it is easy to debug and adjust, making it particularly suitable for scenarios where multiple types of indoor terminals are used in combination.

[0018] In some embodiments, the first The required condensing temperature for each indoor terminal is calculated based on the following condensing capacity calculation model:

[0019] in, , For the first The fifth and sixth fitting parameters of each indoor terminal, For the first The heat exchange requirement of each indoor terminal For the first The effect coefficient of normalized subcooling on capacity of each indoor terminal. For the first The return air temperature or return water temperature of each indoor terminal.

[0020] Based on the above model, this application embodiment considers the functional relationship between heat exchange demand and the actual working state of the terminal, so that the system can dynamically estimate the optimal condensing temperature of each terminal, ensuring that the compressor operation state meets the terminal load without excessive redundancy, thereby improving the overall energy efficiency and control accuracy of the system.

[0021] In some embodiments, the control module is further configured to: The influence coefficient was obtained by fitting the first change relationship table. ; The first change relationship table stores the mapping relationship between the test capability value of the indoor terminal and the normalized superheat.

[0022] In some embodiments, the control module is further configured to: The influence coefficient was obtained by fitting the second change relationship table. ; The second change relationship table stores the mapping relationship between the test capability value of the indoor terminal and the normalized subcooling.

[0023] Based on the first and second change relationship tables mentioned above, the influence coefficients of evaporation and condensation capacity are fitted and estimated. By using a preset relationship table to fit the influence coefficients, complex online modeling or real-time calculation can be avoided. It has the advantages of low implementation cost, fast calculation speed and strong adaptability. By introducing the influence coefficients, the system can more comprehensively consider the non-ideal effects of temperature when estimating target temperature or target pressure, effectively improving the accuracy and robustness of energy efficiency control.

[0024] In some embodiments, determining the air conditioning system's circulation system as either a cooling or heating main unit based on the cooling and / or heating demand capacity of the indoor terminals within the system includes: The cumulative cooling demand is obtained by summing the cooling demand of the indoor terminals in the air conditioning system. : The cumulative heating demand is obtained by summing the heating capacity of the indoor terminals in the air conditioning system. ; Compare the cumulative cooling demand and the cumulative heating demand. If the cumulative cooling demand exceeds the cumulative heating demand, then... If the cooling system is active, then the circulation system is the main cooling system; otherwise, the circulation system is the main heating system.

[0025] In some embodiments, the control module is configured to: The required evaporation pressure or condensation pressure corresponding to the required evaporation temperature or required condensation temperature is determined based on the temperature and pressure lookup table. The temperature and pressure lookup table stores a first mapping relationship between the required evaporation temperature and its corresponding required evaporation pressure, and a second mapping relationship between the required condensation temperature and its corresponding required condensation pressure.

[0026] Once the control module calculates the required evaporation or condensation temperature based on the indoor terminal heat exchange demand, it can directly locate the corresponding pressure value in the lookup table or perform interpolation using adjacent values ​​to obtain a more accurate required evaporation or condensation pressure. This pressure value will serve as the target operating pressure input for the compressor, used for subsequent frequency control and energy efficiency optimization.

[0027] In some embodiments, the first The required condensation temperature for each indoor terminal For the required condensing pressure The saturated condensation temperature value; the first The required evaporation temperature for each indoor terminal Demand evaporation pressure Based on the saturated evaporation temperature value, the corresponding required evaporation pressure or required condensation pressure can be calculated according to the required evaporation temperature or required condensation temperature.

[0028] In the above embodiments, the maximum required condensing pressure It can be represented as ; It can be represented as .

[0029] In some embodiments, if the circulation system is a refrigeration unit, the expansion valve of the indoor terminal in the heating mode is regulated based on the normalized subcooling.

[0030] Specifically, the normalized subcooling is configured to be 0. Based on the normalized subcooling, the expansion valve of the indoor terminal in heating mode is regulated. The heat exchanger of the indoor terminal acts as a condenser. The refrigerant enters the condenser from a high-temperature, high-pressure gaseous state, releases heat to the indoor air through the heat exchanger wall, and gradually condenses into a liquid state. When the normalized subcooling is 0, the refrigerant has basically completed the phase change in the condenser. The condensation process is relatively complete, and there is no excess liquid phase remaining. This indicates that there is only a gas phase and a gas-liquid two-phase heat exchange zone in the terminal heat exchanger, and there is no liquid refrigerant remaining for heat exchange. The heat exchanger has achieved sufficient heat exchange, achieving the optimal capacity of the terminal unit.

[0031] In some embodiments, if the circulation system is the main heating element, the expansion valve of the indoor terminal in the heating mode is adjusted based on the normalized superheat. Specifically, the normalized superheat is configured to be 0, and the expansion valve of the cooling terminal is adjusted based on the normalized superheat. This indicates that there is only a liquid-liquid two-phase heat exchange zone in the terminal heat exchanger, with no gaseous refrigerant remaining for heat exchange. The heat exchanger has achieved sufficient heat exchange, achieving optimal capacity of the terminal unit. Attached Figure Description

[0032] Figure 1 A structural block diagram of a multi-split air conditioning system provided in this application embodiment; Figure 2 The control logic flowchart of the multi-split air conditioning system provided in the embodiments of this application; Figure 3 A schematic diagram of the demand capacity calculation model for different operating modes of indoor terminals provided in the embodiments of this application; Figure 4 Another control logic flowchart of the multi-split air conditioning system provided in the embodiments of this application; Figure 5 Another control logic flowchart of the multi-split air conditioning system provided in the embodiments of this application; Figure 6 Another control logic flowchart of the multi-split air conditioning system provided in the embodiments of this application; Figure 7 Another control logic flowchart of the multi-split air conditioning system provided in the embodiments of this application; Figure 8Another control logic flowchart of the multi-split air conditioning system provided in the embodiments of this application; Figure 9 Another control logic flowchart of the multi-split air conditioning system provided in the embodiments of this application; Figure 10 This is a schematic diagram of the hardware structure of the control module provided in an embodiment of this application.

[0033] In the above figures: 1. Outdoor unit; 2. Indoor terminal unit; 401. Processor; 402. Memory; 403. Communication interface. Detailed Implementation

[0034] To make the objectives and implementation methods of this application clearer, the exemplary implementation methods of this application will be clearly and completely described below with reference to the accompanying drawings of the exemplary embodiments of this application. Obviously, the exemplary embodiments described are only some embodiments of this application, and not all embodiments.

[0035] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms “a,” “an,” “an,” “the,” and similar words used in this application do not indicate quantity limitation and may indicate singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units not listed, or may include other steps or units inherent to these processes, methods, products, or devices. The terms “connected,” “linked,” “coupled,” and similar words used in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. “Multiple” used in this application refers to two or more. “And / or” describes the relationship between related objects, indicating that three relationships may exist; for example, “A and / or B” can represent: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following objects are in an "or" relationship. The terms "first," "second," and "third" used in this application are merely to distinguish similar objects and do not represent a specific ordering of the objects.

[0036] Air conditioners execute refrigeration and heating cycles using a compressor, condenser, expansion valve, and evaporator. These cycles are controlled by a controller, which manages the refrigerant flow and the opening of the expansion valve. The refrigeration and heating cycles involve a series of processes including compression, condensation, expansion, and evaporation, ultimately supplying refrigerant to the conditioned and heat-exchanged air.

[0037] The compressor compresses refrigerant gas under high temperature and pressure and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the outdoor heat exchanger. The outdoor heat exchanger condenses the compressed refrigerant into a liquid phase, and the heat is released to the surrounding environment through the condensation process.

[0038] The expansion valve expands the high-temperature, high-pressure liquid refrigerant condensed in the condenser into a low-pressure liquid refrigerant. The evaporator evaporates the expanded refrigerant in the expansion valve, returning the low-temperature, low-pressure refrigerant gas to the compressor. The evaporator achieves its cooling effect by utilizing the latent heat of refrigerant evaporation to exchange heat with the material being cooled. Throughout the cycle, the air conditioner regulates the temperature of the indoor space.

[0039] An air conditioner outdoor unit refers to the part of the refrigeration cycle that includes the compressor and the outdoor heat exchanger. An air conditioner indoor unit includes the indoor heat exchanger, and an expansion valve can be provided in either the outdoor or indoor unit.

[0040] The indoor and outdoor heat exchangers function as either condensers or evaporators. When the indoor heat exchanger is used as a condenser, the air conditioner functions as a heater in heating mode; when the indoor heat exchanger is used as an evaporator, the air conditioner functions as a cooler in cooling mode.

[0041] refer to Figure 1 As shown in the figure, this application provides a multi-split air conditioning system, including: an outdoor unit 1, at least one indoor terminal 2, a control module, etc. The indoor terminal is connected to the outdoor unit through a pipeline, and the indoor terminal may include a water terminal, a fresh air terminal and / or an indoor unit.

[0042] The outdoor unit is equipped with a compressor, a four-way valve, an outdoor heat exchanger, an outdoor fan, etc.

[0043] A water-based heating system is an indoor heat dissipation device that uses water as a medium to transfer heat; underfloor heating is one common form. It consists of multiple underfloor heating coils connected in parallel. A water valve is installed at the inlet of each underfloor heating coil to control the flow of water. The water valve is controlled by a circuit board on the outdoor unit.

[0044] The fresh air terminal can independently exchange indoor and outdoor air. It includes a shell and a heat exchange core located inside the shell, which has a fresh air duct and a stale air duct. The fresh air in the fresh air duct exchanges heat with the stale air in the stale air duct to recover the heat from the stale air.

[0045] refer to Figure 2 As shown, the control module is configured as follows: The cooling capacity requirement of the indoor terminal is determined based on the air enthalpy difference method. Heating demand capacity ; Establish a terminal output capacity calculation model, use the terminal output capacity calculation model to determine the required evaporation temperature or required condensation temperature of each indoor terminal within a preset cycle, and determine the required evaporation pressure or required condensation pressure corresponding to the required evaporation temperature or required condensation temperature. The air conditioning system's circulation system is determined to be either the cooling main body or the heating main body based on the cooling and / or heating demand capacity of the indoor terminals within the system. If the circulation system is the main heating element, then select the maximum required condensing pressure between the indoor terminals. The target pressure for the compressor is used, and if the circulation system is the main refrigeration unit, the minimum required evaporation pressure between the indoor terminals is selected. The target pressure for the compressor is used to control the air conditioning system to achieve the following energy efficiency control objectives: meeting the most unfavorable heat exchanger requirements, ensuring the minimum suction and discharge pressure difference, minimizing compressor power consumption, and meeting actual needs.

[0046] Based on the above configuration, the air conditioning system of this application assesses the load demand of each indoor terminal in real time, including cooling and heating demand. On this basis, the system constructs a terminal output capacity calculation model to periodically predict the required evaporation temperature or required condensation temperature of each indoor terminal, and further converts it into required evaporation pressure or required condensation pressure.

[0047] By comprehensively judging these pressure values, the system determines whether the current air conditioning circulation system should operate in cooling or heating mode, and accordingly selects the minimum required evaporating pressure or the maximum required condensing pressure as the target pressure setpoint for the compressor. This control logic ensures that the system prioritizes meeting the operational needs of the most unfavorable terminal (i.e., the terminal with the greatest heat exchange demand), and on this basis, minimizes the compressor's suction and discharge pressure difference, thereby reducing compressor power consumption and improving overall energy efficiency.

[0048] This implementation method effectively improves the accuracy of indoor terminal demand identification by introducing a terminal calculation model. Using accurately predicted demand temperature and pressure, the control module can set a more scientific target pressure for the compressor, ensuring the system prioritizes meeting the operational needs of the most unfavorable terminals. Simultaneously, by controlling the compressor's target pressure to minimize the suction and discharge pressure difference, compressor energy consumption is significantly reduced, thereby improving the overall energy efficiency ratio (EER / COP) and reducing operating costs. Furthermore, the system has excellent adaptive capabilities, dynamically adjusting operating modes and control strategies to ensure optimal operation under various conditions, enhancing user comfort and equipment stability.

[0049] In the above embodiments, when the indoor terminal is a water terminal, the heating demand capacity of this application is... This represents the heating demand capacity. .

[0050] In some embodiments, the control module uses a PID control method to adjust the compressor frequency so that the real-time pressure of the compressor is equal to or close to the target pressure, thereby achieving dynamic optimization control of the operating pressure and improving the overall operating efficiency of the machine.

[0051] Specifically, the control module calculates the deviation between the real-time pressure and the set target pressure. Based on the magnitude of this deviation (proportional term), the cumulative amount of the deviation over time (integral term), and the rate of change of the deviation (derivative term), it outputs control commands to adjust the compressor's operating frequency. Through continuous closed-loop feedback control, the compressor's operating frequency can be finely adjusted, thereby enabling its actual discharge pressure or intake pressure to quickly approach the preset target pressure, achieving dynamic and stable control.

[0052] In some embodiments, the control module is configured with a demand capacity calculation cycle. The above logic is executed cyclically according to the demand capacity calculation cycle to dynamically determine the target pressure for each demand capacity calculation cycle. By setting the demand capacity calculation cycle and realizing periodic dynamic evaluation, the system can quickly respond to changes in end load and improve the timeliness and accuracy of control.

[0053] In some embodiments, this application calculates the heating or cooling capacity of the terminal based on the terminal outlet status. Considering the specific terminal type, such as water terminal, fresh air terminal, cooling / heating-only terminal, or conventional cooling / heating terminal, which affects the capacity demand, this application establishes a capacity demand calculation model considering relevant factors, including: air supply / return mode setting, terminal outlet status, and whether a humidity sensor is installed on the terminal. Figure 3 As shown.

[0054] like Figure 3As shown, when the indoor terminal is an indoor unit, its cooling capacity can be calculated based on the following process: Obtain the inlet enthalpy value of the indoor terminal. With export enthalpy The first difference, based on the first difference and the set air volume The cooling demand capacity is calculated by multiplying the product. Cooling demand capacity This can be represented by the following computational model: .

[0055] This implementation method is based on the principle of enthalpy difference. It reflects the heat absorption capacity of air by measuring the difference in enthalpy between the inlet and outlet of the indoor unit, thereby indirectly calculating the current cooling demand of the terminal.

[0056] like Figure 3 As shown, when the indoor terminal is an indoor unit, its heating capacity can be calculated based on the following process: Obtain the outlet enthalpy of the indoor terminal. With entrance enthalpy The second difference, based on the second difference and the set air volume The product is used to calculate the heating demand capacity. Heating demand capacity This can be represented by the following computational model: .

[0057] In this implementation, the assessment of heating demand capacity is also based on the air enthalpy difference method, but in the opposite direction to the enthalpy difference in cooling mode. In heating mode, air flows into the indoor terminal from the inlet, is heated, and then discharged from the outlet, increasing its enthalpy value. The control module collects the enthalpy values ​​of the air outlet and the air inlet in real time, calculates the difference as the heat absorbed per unit mass of air, and combines this with the set airflow to determine the corresponding heating demand capacity.

[0058] This model can dynamically reflect changes in the actual heating load at the terminal, using air-side data for demand estimation, avoiding complex refrigerant-side measurements, and improving system layout flexibility. It is particularly suitable for central air conditioning systems with multiple terminals and variable operating conditions. The model also boasts excellent real-time performance and scalability, helping to improve heating operation accuracy, shorten response time, and enhance user comfort and system energy efficiency.

[0059] In the above embodiments, the air volume is set. It can be the airflow at the user-defined speed setting. The airflow of the air conditioning system at different speed settings is determined in advance through testing and stored as preset values ​​in the control module.

[0060] In the above embodiments, the inlet enthalpy value With export enthalpy It can be based on the inlet temperature of the air conditioning terminal. outlet temperature Inlet humidity, outlet humidity Calculated. Inlet temperature outlet temperature Inlet and outlet humidity can be obtained based on the temperature and humidity sensors installed in the indoor terminal. The outlet temperature... Export humidity It can be the user-defined value obtained.

[0061] Terminal demand assessment can be completed solely based on air-side parameters (temperature, humidity, and airflow), eliminating the need for complex refrigerant-side measurements and significantly simplifying system structure and reducing costs. It is particularly suitable for multi-split air conditioning systems with a large number of terminals and complex distribution, helping to improve the accuracy and sensitivity of the overall system in sensing terminal loads, thereby supporting precise target pressure regulation and energy efficiency optimization control.

[0062] In another embodiment, considering that some air conditioning units are not equipped with humidity sensors, the inlet humidity can be obtained by connecting the control module to a weather forecasting tool. Specifically, a weather API service (such as OpenWeatherMap) is registered and an API key is obtained. This ensures the control module has network connectivity (Wi-Fi / 4G, etc.). A program is written to initiate an HTTP request, obtain weather data in JSON format, parse the JSON, extract the humidity field, and perform logical judgments and device control based on the humidity value. Conversely, the outlet humidity is configured to a preset relative humidity.

[0063] like Figure 3 As shown, the water terminal obtains the user-configured outlet water temperature. The heating demand capacity at the water terminal can be calculated based on the following process: The outlet water temperature of the indoor terminal (i.e., the water terminal) is obtained by measuring with sensors. With water temperature The third difference represents the heat released per unit mass of water at the end, based on the relationship between the third difference and the water flow rate. Preset specific heat capacity The product is used to calculate the heating demand capacity at the water terminal. Heating demand capacity This can be represented by the following computational model: The specific heat capacity is preset here. Use a fixed value (e.g., 4.186 kJ / kg·℃) or adjust it dynamically with temperature.

[0064] This model can improve the response speed and temperature control stability of heating systems, and reduce energy waste caused by misjudged loads. The calculation model also has good compatibility and can be seamlessly integrated into various hot water systems such as centralized heating, underfloor heating, and modular boiler control, improving overall operating efficiency and control accuracy.

[0065] In the above embodiments, water flow rate It can be obtained in real time, and can be achieved through mass flow meters, differential pressure flow meters or pump frequency feedback.

[0066] In some embodiments, reference Figure 4 As shown, determining the required evaporation temperature or required condensation temperature of each indoor terminal within a preset cycle using the terminal output capacity calculation model further includes: Determine whether the indoor terminal operates in cooling or heating mode. Calculate the required heat exchange for each of the indoor terminals, the first... The heat exchange requirement of each indoor terminal is denoted as . ; If the indoor terminal is in cooling mode, the required evaporation temperature of the indoor terminal is calculated based on the total required heat exchange using the evaporation capacity calculation model in the terminal output capacity calculation model. If the indoor terminal is in heating mode, the required condensing temperature of the indoor terminal is calculated based on the total required heat exchange using the condensing capacity calculation model in the terminal output capacity calculation model.

[0067] This implementation method deeply integrates cooling / heating status identification, demand heat exchange calculation, and terminal capacity model, realizing a quantitative mapping between heat exchange capacity and operating temperature, thereby improving the rationality and accuracy of the system target temperature setting.

[0068] By working backward from the load to determine the required temperature, this approach better matches actual operating conditions compared to fixed, empirically-based settings, improving comfort and energy efficiency. This mechanism also enhances the system's intelligent adjustment capabilities, making it particularly suitable for multi-terminal collaborative operation scenarios. It effectively supports personalized load matching and energy allocation strategies, helping to optimize overall system performance, reduce energy consumption, and improve control stability.

[0069] In some embodiments, the required heat exchange of the indoor terminal in heating mode is obtained by calculating the change in sensible heat of the indoor terminal; the required heat exchange of the indoor terminal in cooling mode is obtained by calculating the change in sensible heat of the indoor terminal. and latent heat change The results show that the indoor terminal in heating mode can be either an indoor unit configured for heating or a water terminal for heating. For indoor terminals in heating mode, their main function is to increase the dry-bulb temperature of the air, so only the change in sensible heat needs to be calculated to assess the heat exchange demand. For indoor terminals in cooling mode, the air is usually dehumidified while cooling down, so the heat exchange includes both sensible heat and latent heat.

[0070] By modeling the heat exchange requirements under heating and cooling conditions separately, the actual heat exchange process at the terminal can be more accurately reflected, improving the accuracy of system heat exchange capacity identification. Separate modeling of sensible and latent heat provides a reliable foundation for subsequent core functions such as terminal capacity matching, evaporation / condensation temperature estimation, and target pressure control.

[0071] Examples, but not limited to, based on the heat transfer equation Perform heat exchange calculations, where For the temperature difference, KA is the heat transfer fitting coefficient. In the calculation of sensible heat temperature difference, the parameters that can be selected include return air temperature. In the calculation of latent heat temperature difference, the parameters that can be selected include dew point temperature. The heat transfer temperature difference is obtained by the difference between evaporation temperature, return air temperature, and dew point temperature.

[0072] In some embodiments, the first The required evaporation temperature for each indoor terminal is calculated based on the following evaporation capacity calculation model:

[0073] in, , , , For the first The first, second, third, and fourth fitting parameters for each indoor terminal. For the first The heat exchange requirement of each indoor terminal For the first The effect coefficient of normalized superheat on capacity of each indoor terminal. For the first The return air temperature at each indoor terminal For the first The dew point temperature of an indoor terminal can be calculated from the temperature and humidity.

[0074] Based on the aforementioned evaporation capacity calculation model, this embodiment establishes a functional mapping relationship between heat exchange demand and terminal operating conditions. This allows the calculation of the required evaporation temperature to no longer rely on static settings or empirical values, but rather on dynamic estimation based on real-time operating data and fitted parameters, resulting in high accuracy and adaptability. The model structure is clear, the physical meaning of the parameters is explicit, and it is easy to debug and adjust, making it particularly suitable for scenarios where multiple types of indoor terminals are used in combination.

[0075] Because this method can accurately reflect the capacity differences of different terminals, it helps to improve the overall load matching efficiency and energy efficiency of the system, and also supports the integration needs of heat pumps or converter control in future systems.

[0076] In the above embodiments, considering that factors such as the type of heat exchanger and air / water flow rate of the indoor terminal will affect the heat transfer coefficient of the terminal, the first fitting parameter, the second fitting parameter, the third fitting parameter and the fourth fitting parameter are obtained by fitting based on the relationship between the terminal capacity value and the temperature difference obtained from the experiment.

[0077] In some embodiments, the first The required condensing temperature for each indoor terminal is calculated based on the following condensing capacity calculation model:

[0078] in, , For the first The fifth and sixth fitting parameters of each indoor terminal, For the first The heat exchange requirement of each indoor terminal For the first The effect coefficient of normalized subcooling on capacity of each indoor terminal. For the first The return air temperature or return water temperature of each indoor terminal.

[0079] Based on the above model, this application embodiment considers the functional relationship between heat exchange demand and the actual working state of the terminal, so that the system can dynamically estimate the optimal condensing temperature of each terminal, ensuring that the compressor operation state meets the terminal load without excessive redundancy, thereby improving the overall energy efficiency and control accuracy of the system.

[0080] In some embodiments, reference Figure 5 As shown, the control module is also configured as follows: The influence coefficient was obtained by fitting the first change relationship table. ; The first change relationship table stores the mapping relationship between the test capability value of the indoor terminal and the normalized superheat.

[0081] In some embodiments, referenceFigure 5 As shown, the control module is also configured as follows: The influence coefficient was obtained by fitting the second change relationship table. ; The second change relationship table stores the mapping relationship between the test capability value of the indoor terminal and the normalized subcooling.

[0082] Based on the first and second change relationship tables mentioned above, the influence coefficients of evaporation and condensation capacity are fitted and estimated. By using a preset relationship table to fit the influence coefficients, complex online modeling or real-time calculation can be avoided. It has the advantages of low implementation cost, fast calculation speed and strong adaptability. By introducing the influence coefficients, the system can more comprehensively consider the non-ideal effects of temperature when estimating target temperature or target pressure, effectively improving the accuracy and robustness of energy efficiency control.

[0083] In another embodiment, the first and second change relation tables can be replaced by functional expressions, such as piecewise linear models, logarithmic functions, or higher-order polynomial functions, to achieve higher fitting accuracy; alternatively, artificial intelligence methods (such as neural networks) can be used to train the relation model and deploy a predictor during operation to replace table lookup.

[0084] In some embodiments, reference Figure 7 As shown, determining whether the air conditioning system's circulation system is the cooling main body or the heating main body based on the cooling and / or heating demand capacity of the indoor terminals within the system includes: The cumulative cooling demand is obtained by summing the cooling demand of the indoor terminals in the air conditioning system. : The cumulative heating demand is obtained by summing the heating capacity of the indoor terminals in the air conditioning system. ; Compare the cumulative cooling demand and the cumulative heating demand. If the cumulative cooling demand exceeds the cumulative heating demand, then... If the cooling system is active, then the circulation system is the main cooling system; otherwise, the circulation system is the main heating system.

[0085] It is understandable that when the indoor terminal of the air conditioning system has a single cooling demand, the minimum required evaporation pressure of the indoor terminal is dynamically selected as the target pressure of the compressor. Conversely, when the indoor terminal of the air conditioning system has a single heating demand, the maximum required condensation pressure of the indoor terminal is dynamically selected as the target pressure of the compressor.

[0086] In some embodiments, reference Figure 8 As shown, the control module is also configured as follows: The required evaporation pressure or condensation pressure corresponding to the required evaporation temperature or required condensation temperature is determined based on the temperature and pressure lookup table. The temperature and pressure lookup table stores a first mapping relationship between the required evaporation temperature and its corresponding required evaporation pressure, and a second mapping relationship between the required condensation temperature and its corresponding required condensation pressure.

[0087] Once the control module calculates the required evaporation or condensation temperature based on the indoor terminal heat exchange demand, it can directly locate the corresponding pressure value in the lookup table or perform interpolation using adjacent values ​​to obtain a more accurate required evaporation or condensation pressure. This pressure value will serve as the target operating pressure input for the compressor, used for subsequent frequency control and energy efficiency optimization.

[0088] By replacing complex state equation solving with a lookup table approach, the real-time computational burden on the control module is significantly simplified, improving response speed and system stability. For terminal heat exchange requirements under different operating modes, this method can quickly achieve a closed-loop mapping from heat regulation requirements to equipment control parameters (pressure), improving the real-time performance and overall energy efficiency of the control system.

[0089] In the optional scheme, the temperature and pressure lookup table can adopt a multi-dimensional structure, supporting the simultaneous lookup of corrected pressures under saturated, superheated / supercooled conditions; it can also be combined with curve fitting methods (such as polynomial interpolation and spline interpolation) to generate an equivalent calculation model, saving storage space and improving lookup accuracy.

[0090] In some embodiments, the first The required condensation temperature for each indoor terminal For the required condensing pressure The saturated condensation temperature value; the first The required evaporation temperature for each indoor terminal Demand evaporation pressure Based on the saturated evaporation temperature value, the corresponding required evaporation pressure or required condensation pressure can be calculated according to the required evaporation temperature or required condensation temperature.

[0091] In the above embodiments, the maximum required condensing pressure It can be represented as ; It can be represented as .

[0092] In some embodiments, reference Figure 9 As shown, if the circulation system is the main cooling unit, the expansion valve of the indoor terminal in the heating mode is adjusted based on the normalized subcooling.

[0093] Specifically, the normalized subcooling is configured to be 0. Based on the normalized subcooling, the expansion valve of the indoor terminal in heating mode is regulated. The heat exchanger of the indoor terminal acts as a condenser. The refrigerant enters the condenser from a high-temperature, high-pressure gaseous state, releases heat to the indoor air through the heat exchanger wall, and gradually condenses into a liquid state. When the normalized subcooling is 0, the refrigerant has basically completed the phase change in the condenser. The condensation process is relatively complete, and there is no excess liquid phase remaining. This indicates that there is only a gas phase and a gas-liquid two-phase heat exchange zone in the terminal heat exchanger, and there is no liquid refrigerant remaining for heat exchange. The heat exchanger has achieved sufficient heat exchange, achieving the optimal capacity of the terminal unit.

[0094] In some embodiments, reference Figure 9 As shown, if the circulation system is the main heating system, the expansion valve of the indoor terminal in the heating mode is adjusted based on the normalized superheat. Specifically, if the normalized superheat is configured to be 0, the expansion valve of the cooling terminal is adjusted based on the normalized superheat. This indicates that there is only a liquid-liquid two-phase heat exchange zone in the terminal heat exchanger, with no gaseous refrigerant remaining for heat exchange. The heat exchanger has achieved sufficient heat exchange, achieving optimal capacity of the terminal unit.

[0095] It should be noted that the above modules can be functional modules or program modules, and can be implemented through software or hardware. For modules implemented through hardware, the above modules can reside in the same processor; or the above modules can be located in different processors in any combination.

[0096] in addition, Figure 10 This is a schematic diagram of the hardware structure of the control module according to an embodiment of this application.

[0097] The control module may include a processor 401 and a memory 402 storing computer program instructions.

[0098] Specifically, the processor 401 may include a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits that can be configured to implement the embodiments of this application.

[0099] Memory 402 may include a large-capacity memory for data or instructions. For example, and not limitingly, memory 402 may include a hard disk drive (HDD), a floppy disk drive, a solid-state drive (SSD), flash memory, an optical disk drive, a magneto-optical disk drive, magnetic tape, or a Universal Serial Bus (USB) drive, or a combination of two or more of these. Where appropriate, memory 402 may include removable or non-removable (or fixed) media. Where appropriate, memory 402 may be internal or external to a data processing device. In a particular embodiment, memory 402 is non-volatile memory. In a particular embodiment, memory 402 includes read-only memory (ROM) and random access memory (RAM). Where appropriate, the ROM may be a mask-programmed ROM, a programmable read-only memory (PROM), an erasable read-only memory (EPROM), an electrically erasable read-only memory (EEPROM), an electrically alterable read-only memory (EAROM), or flash memory, or a combination of two or more of these. Where appropriate, the RAM can be Static Random-Access Memory (SRAM) or Dynamic Random-Access Memory (DRAM). DRAM can be Fast Page Mode Dynamic Random Access Memory (FPMDRAM), Extended Data Out Dynamic Random Access Memory (EDODRAM), Synchronous Dynamic Random-Access Memory (SDRAM), etc.

[0100] The memory 402 can be used to store or cache various data files that need to be processed and / or communicated, as well as possible computer program instructions executed by the processor 401.

[0101] The processor 401 reads and executes computer program instructions stored in the memory 402 to implement the built-in arithmetic operations of the control module in the above embodiments.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0103] For ease of explanation, the above description has been provided in conjunction with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or to limit the embodiments to the specific forms disclosed above. Various modifications and variations can be obtained based on the above teachings. The selection and description of the above embodiments are for the purpose of better explaining the principles and practical applications, thereby enabling those skilled in the art to better utilize the embodiments and various different variations of the embodiments suitable for specific application considerations.

Claims

1. A multi-split air conditioning system, characterized in that, include: The outdoor unit is equipped with a compressor; At least one indoor terminal is connected to the outdoor unit via a pipeline; The control module is configured as follows: Determine the cooling and heating capacity requirements of the indoor terminals; Establish a terminal output capacity calculation model, use the terminal output capacity calculation model to determine the required evaporation temperature or required condensation temperature of each indoor terminal within a preset cycle, and determine the required evaporation pressure or required condensation pressure corresponding to the required evaporation temperature or required condensation temperature. The air conditioning system's circulation system is determined to be either the cooling main body or the heating main body based on the cooling and / or heating demand capacity of the indoor terminals within the system. If the circulation system is the main heating component, the maximum required condensing pressure between the indoor terminals is selected as the target pressure of the compressor; if the circulation system is the main cooling component, the minimum required evaporating pressure between the indoor terminals is selected as the target pressure of the compressor.

2. The multi-split air conditioning system according to claim 1, characterized in that, The step of determining the required evaporation temperature or required condensation temperature of each indoor terminal within a preset cycle using the terminal output capacity calculation model further includes: Determine whether the indoor terminal operates in cooling or heating mode. Calculate the required heat exchange for each of the indoor terminals; If the indoor terminal is in cooling mode, the required evaporation temperature of the indoor terminal is calculated based on the total required heat exchange using the evaporation capacity calculation model in the terminal output capacity calculation model. If the indoor terminal is in heating mode, the required condensing temperature of the indoor terminal is calculated based on the total required heat exchange using the condensing capacity calculation model in the terminal output capacity calculation model.

3. The multi-split air conditioning system according to claim 2, characterized in that, The required evaporation temperature at the indoor terminal is calculated based on the following evaporation capacity calculation model: in, , , , For the first The first, second, third, and fourth fitting parameters for each indoor terminal. For the first The heat exchange requirement of each indoor terminal For the first The effect coefficient of normalized superheat on capacity of each indoor terminal. For the first The return air temperature at each indoor terminal For the first The dew point temperature value of each indoor terminal.

4. The multi-split air conditioning system according to claim 2, characterized in that, The required condensing temperature for indoor terminals is calculated based on the following condensing capacity calculation model: in, , For the first The fifth and sixth fitting parameters of each indoor terminal, For the first The heat exchange requirement of each indoor terminal For the first The effect coefficient of normalized subcooling on capacity of each indoor terminal. For the first The return air temperature or return water temperature of each indoor terminal.

5. The multi-split air conditioning system according to claim 3, characterized in that, The control module is also configured to: The influence coefficient was obtained by fitting the first change relationship table. ; The first change relationship table stores the mapping relationship between the test capability value of the indoor terminal and the normalized superheat.

6. The multi-split air conditioning system according to claim 4, characterized in that, The control module is also configured to: The influence coefficient was obtained by fitting the second change relationship table. ; The second change relationship table stores the mapping relationship between the test capability value of the indoor terminal and the normalized subcooling.

7. The multi-split air conditioning system according to claim 1, characterized in that, The step of determining the air conditioning system's circulation system as the cooling or heating main body based on the cooling and / or heating demand capacity of the indoor terminals within the system includes: The cumulative cooling demand is obtained by summing the cooling demand capacity of the indoor terminals in the air conditioning system: The cumulative heating demand is obtained by summing the heating demand capacity of the indoor terminals in the air conditioning system. By comparing the cumulative cooling demand and the cumulative heating demand, if the cumulative cooling demand exceeds the cumulative heating demand, then the circulation system is the main cooling system; otherwise, the circulation system is the main heating system.

8. The multi-split air conditioning system according to claim 7, characterized in that, The control module is configured as follows: The required evaporation pressure or condensation pressure corresponding to the required evaporation temperature or required condensation temperature is determined based on the temperature and pressure lookup table. The temperature and pressure lookup table stores a first mapping relationship between the required evaporation temperature and its corresponding required evaporation pressure, and a second mapping relationship between the required condensation temperature and its corresponding required condensation pressure.

9. The multi-split air conditioning system according to any one of claims 1 to 8, characterized in that, If the circulation system is a refrigeration unit, the expansion valve of the indoor terminal in the heating mode is adjusted based on the normalized subcooling.

10. The multi-split air conditioning system according to any one of claims 1 to 8, characterized in that, If the circulation system is the main heating element, the expansion valve of the indoor terminal in cooling mode is adjusted based on the normalized superheat.

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