Energy efficiency online control air conditioning unit

Abstract

The invention discloses an energy efficiency online control air conditioning unit which comprises a compressor, a condenser, an economizer and an evaporator which are connected together to form a refrigeration cycle, and further comprises a plurality of pressure sensors, a plurality of temperature sensors, a frequency converter and a controller. The frequency converter is connected with the compressor and the controller and feeds back the real-time output power output by the frequency converter to the compressor to the controller. The pressure sensors and the temperature sensors are connected with the controller and used for detecting the refrigerant pressure and temperature of multiple positions in the refrigeration cycle and transmitting the refrigerant pressure and temperature to the controller. And the controller calculates according to the refrigerant pressure, the temperature and the real-time output power according to energy conservation and mass conservation to obtain the refrigerating capacity or the heating capacity and the unit energy efficiency under the corresponding operation working conditions. The refrigerating capacity or the heating capacity and the energy efficiency of the unit are solved in real time according to the refrigerant side state parameters, the energy conservation principle and the mass conservation principle, the dependence on historical data is reduced compared with a neural network model algorithm, and the detection consistency and accuracy are improved.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, and more specifically to an air conditioning unit with online energy efficiency control. Background Technology

[0002] Central air conditioning systems in buildings account for a significant proportion of total social energy consumption. Therefore, the real-time energy efficiency of centrifugal chillers (heat pumps) is of great concern in order to reduce energy consumption.

[0003] Conventional chiller (heat pump) units typically use sensors to collect operating status parameters of the refrigerant side working fluid (inlet and outlet temperatures, refrigerant flow rate, etc.) and motor power consumption to calculate the unit's cooling capacity (heating capacity) and assess energy efficiency. However, the measurement accuracy of the operating status parameters of the refrigerant side working fluid (inlet and outlet temperatures, flow rate, etc.) is limited, with a comprehensive error of up to 20% or more. Furthermore, the sensor collection of operating status parameters of the refrigerant side working fluid is subject to many limitations, such as the unit's installation space and the sensor's installation location.

[0004] Furthermore, to reduce energy consumption, real-time optimization and control of operating energy efficiency are necessary to ensure optimal operation, thereby reducing energy efficiency and ultimately lowering power consumption. Conventional energy efficiency optimization control for chiller (heat pump) units relies on a large amount of historical operating data, using neural networks, machine learning, and other methods to achieve load forecasting before energy efficiency optimization control. However, this method requires a large amount of actual operating data to train the load forecasting model; the accuracy of the trained load forecasting model significantly impacts the effectiveness of energy efficiency optimization control; and this approach is also poorly suited for newly commissioned chiller (heat pump) units.

[0005] The information disclosed in this background section is only intended to enhance the understanding of the background technology of this application, and therefore may include prior art that is not known to those skilled in the art. Summary of the Invention

[0006] To address the issues of accuracy and numerous limitations in online energy efficiency monitoring and optimization control of centrifugal chillers mentioned in the background art, this invention proposes an online energy efficiency control air conditioning unit. This unit calculates its cooling or heating capacity and energy efficiency in real time based on refrigerant-side state parameters, reducing reliance on historical data and improving the accuracy and consistency of energy efficiency monitoring.

[0007] To achieve the above-mentioned objectives, the present invention employs the following technical solution:

[0008] An energy-efficient online control air conditioning unit includes a compressor, condenser, economizer, and evaporator connected together to form a refrigeration cycle system, and also includes multiple pressure sensors, multiple temperature sensors, a frequency converter, and a controller;

[0009] The frequency converter is connected to the compressor and the controller respectively, and feeds back the real-time output power of the compressor to the controller; each of the pressure sensors and each of the temperature sensors are respectively set at different positions in the refrigeration cycle system and connected to the controller, for detecting the refrigerant pressure and temperature at each position and transmitting them to the controller;

[0010] The controller establishes a set of energy conservation and mass conservation equations based on the refrigerant pressure, temperature, and real-time output power to obtain the cooling or heating capacity and unit energy efficiency under the corresponding operating conditions.

[0011] In some specific embodiments, each of the pressure sensors is respectively installed on the exhaust port of the economizer, the evaporator, the condenser, and the compressor to detect the refrigerant pressure of the economizer, the refrigerant pressure of the evaporator, the refrigerant pressure of the condenser, and the exhaust pressure;

[0012] Each of the temperature sensors is respectively installed in the exhaust pipe and at the bottom of the condenser, and is used to detect the exhaust temperature and the subcooling temperature, respectively;

[0013] Obtaining the cooling or heating capacity includes the following steps:

[0014] S1. Calculate the enthalpy of the saturated refrigerant gas at the outlet of the evaporator based on the refrigerant pressure of the evaporator;

[0015] S2. Calculate the enthalpy of the superheated refrigerant gas at the exhaust port of the compressor based on the exhaust pressure and the exhaust temperature;

[0016] S3. Calculate the liquid enthalpy of the subcooled refrigerant at the bottom of the condenser based on the subcooling temperature;

[0017] S4. Obtain the enthalpy value of the two-phase refrigerant at the inlet of the economizer based on the enthalpy value of the subcooled refrigerant liquid;

[0018] S5. Calculate the saturated refrigerant liquid enthalpy at the bottom outlet of the economizer based on the refrigerant pressure of the economizer.

[0019] S6. Calculate the enthalpy of the saturated refrigerant gas at the top outlet of the economizer based on the refrigerant pressure of the economizer.

[0020] S7. Calculate the output power of the compressor based on the real-time output power, i.e., the compressor output power;

[0021] S8. Based on the above enthalpy values ​​and the compressor output power, establish an energy conservation and mass conservation equation set to obtain the refrigerant mass flow rate;

[0022] S9. Calculate the cooling capacity or heating capacity based on the refrigerant mass flow rate.

[0023] In some specific embodiments, the controller is configured with a gas replenishment state and a non-gas replenishment state;

[0024] When in the gas replenishment state, the refrigerant mass flow rate is calculated based on the saturated refrigerant gas enthalpy at the outlet of the evaporator, the superheated refrigerant gas enthalpy at the discharge port of the compressor, the subcooled refrigerant liquid enthalpy at the bottom of the condenser, the two-phase refrigerant enthalpy at the inlet of the economizer, the saturated refrigerant liquid enthalpy at the bottom outlet of the economizer, the saturated refrigerant gas enthalpy at the top outlet of the economizer, and the compressor output power.

[0025] When in the non-refilled gas state, the refrigerant mass flow rate is calculated based on the saturated refrigerant gas enthalpy at the outlet of the evaporator, the superheated refrigerant gas enthalpy at the exhaust port of the compressor, the subcooled refrigerant liquid enthalpy at the bottom of the condenser, and the compressor output power.

[0026] In some specific embodiments, a cooling liquid supply line and a flow sensor are also included; one end of the cooling liquid supply line is connected to the condenser to provide liquid refrigerant for cooling; the flow sensor and the temperature sensor are respectively installed on the cooling liquid supply line to detect the flow rate and temperature of the cooling liquid refrigerant and transmit them to the controller;

[0027] The cooling capacity loss is calculated based on the enthalpy of the saturated refrigerant gas at the outlet of the evaporator, the enthalpy of the superheated refrigerant gas at the discharge port of the compressor, the enthalpy of the subcooled refrigerant liquid at the bottom of the condenser, the enthalpy of the saturated refrigerant liquid at the bottom outlet of the economizer, the flow rate of the cooling liquid refrigerant, and the temperature of the cooling liquid refrigerant.

[0028] The cooling capacity or heating capacity is obtained by correcting the cooling loss to obtain the corrected cooling capacity or heating capacity.

[0029] In some specific embodiments, the unit energy efficiency calculation includes the following steps:

[0030] S10. Calculate the unit input power based on the real-time output power;

[0031] S11, The ratio of the unit's input power to the corrected cooling capacity or heating capacity is the unit's energy efficiency.

[0032] In some specific embodiments, the enthalpy values ​​of the saturated refrigerant gas, the superheated refrigerant gas, the subcooled refrigerant liquid, the two-phase refrigerant, the enthalpy value of the saturated refrigerant liquid, the compressor output power, the unit input power, the cooling loss, and the corrected cooling capacity or heating capacity are all calculated by formulas obtained by fitting the test data of the changes to a quadratic regression curve.

[0033] In some specific embodiments, the compressor transmits its rotational speed to the controller; the controller is configured with a rotational speed threshold, a duration threshold, and an energy efficiency optimization control module; when the change in rotational speed does not exceed the rotational speed threshold, it is determined to be a stable state, and a stable state timer is started; the stable state timer is compared with the duration threshold.

[0034] When the steady-state time exceeds the duration threshold, the energy efficiency optimization control module is executed; otherwise, the energy efficiency optimization control module is not executed.

[0035] In some specific embodiments, the energy efficiency optimization control module includes an optimal energy efficiency acquisition module, which includes:

[0036] Obtain the refrigerant pressure of the economizer, the refrigerant pressure of the condenser, and the refrigerant pressure of the evaporator;

[0037] Set the pressure step size; obtain multiple pressure combinations by increasing or decreasing the refrigerant pressure of the economizer, the refrigerant pressure of the condenser, and the refrigerant pressure of the evaporator by an integer multiple of the pressure step size;

[0038] Multiple cooling or heating capacities are calculated based on the current unit input power and various pressure combinations, and the maximum value among them is taken as the optimal cooling or heating capacity.

[0039] In some specific embodiments, the controller is configured with a surge detection module to determine whether the unit has a surge risk; and is configured to determine whether the pressure combination corresponding to the optimal cooling capacity or heating capacity has a surge risk through the surge detection module;

[0040] If so, the pressure combination corresponding to each of the cooling or heating capacities is judged in descending order to determine whether there is a surge risk, until a pressure combination without surge risk is found, and it is set as the target pressure combination.

[0041] If not, then the pressure combination corresponding to the optimal cooling capacity or heating capacity is the target pressure combination.

[0042] In some specific embodiments, a first electric regulating valve, a second electric regulating valve, and a third electric regulating valve are also included, which are respectively connected to the controller and respectively installed on the gas supply line, the connection line between the condenser and the economizer, and the connection line between the evaporator and the economizer;

[0043] The energy efficiency optimization control module also includes an electric regulating valve opening control module, which includes:

[0044] Obtain the current opening degree of the first electric regulating valve, the second electric regulating valve, and the third electric regulating valve;

[0045] Calculate the target opening degree of the first electric regulating valve, the second electric regulating valve, and the third electric regulating valve based on the target pressure combination;

[0046] The adjustment opening of the first electric regulating valve, the second electric regulating valve, and the third electric regulating valve is calculated based on the current opening and the target opening.

[0047] The energy-efficient online control air conditioning unit of this invention detects pressure and temperature at different locations on the refrigerant side, and solves a system of equations based on energy and mass conservation to obtain the cooling capacity or heating capacity and unit energy efficiency. This solves the problems of difficult sensor installation and low detection signal accuracy on the refrigerant side, improving the accuracy of the unit's cooling capacity or heating capacity and unit energy efficiency. Furthermore, the method of calculating cooling capacity or heating capacity and unit energy efficiency based on energy conservation, mass conservation, and real-time operating conditions, as well as the neural network training model, does not rely on historical data of unit operation. This ensures consistent accuracy in the detection of cooling capacity or heating capacity and unit energy efficiency from beginning to end, improving the applicability of real-time energy efficiency monitoring and the consistency of detection results.

[0048] Other features and advantages of the present invention will become clearer after reading the detailed embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 This is a schematic diagram showing the composition and connection of an energy-efficient online control air conditioning unit according to an embodiment;

[0051] Figure 2 This is a schematic diagram of the unit's pressure and enthalpy under the gas replenishment state according to an embodiment;

[0052] Figure 3 This is a schematic diagram of the unit's pressure and enthalpy under non-gas-replenishment conditions according to an embodiment;

[0053] Figure 4 This is a schematic diagram illustrating the process of obtaining cooling capacity or heating capacity and unit energy efficiency according to an embodiment;

[0054] Figure 5 This is a schematic diagram of the process for obtaining cooling capacity or heating capacity according to an embodiment;

[0055] Figure 6 This is a schematic diagram of the mass flow rate acquisition process under both gas replenishment and non-gas replenishment states according to an embodiment.

[0056] Figure 7 This is a schematic diagram of the process for obtaining cooling loss according to an embodiment;

[0057] Figure 8 This is a schematic diagram of the unit energy efficiency acquisition process according to an embodiment;

[0058] Figure 9 This is a schematic diagram of the energy efficiency optimization control judgment process according to an embodiment;

[0059] Figure 10 This is a schematic diagram of the target pressure combination acquisition process according to an embodiment;

[0060] Figure 11 This is a schematic diagram of the opening adjustment process of each electric regulating valve according to the embodiment.

[0061] Figure label,

[0062] 1. Evaporator; 2. Condenser; 3. Economizer; 4. Compressor; 5. Inverter; 6. External power supply; 7. Controller; 8. Motor; 11. First pressure sensor; 12. Second pressure sensor; 13. Third pressure sensor; 14. Fourth pressure sensor; 15. First temperature sensor; 16. Second temperature sensor; 17. Third temperature sensor; 18. Flow sensor; 19. First electric regulating valve; 20. Second electric regulating valve; 21. Third electric regulating valve;

[0063] 101. Compressor suction line; 201. Inverter cooling liquid supply line; 202. Motor cooling liquid supply line; 203. First main line; 301. Air replenishment line; 302. Second main line; 402. Compressor discharge line. Detailed Implementation

[0064] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0065] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0066] 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, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "multiple" means two or more.

[0067] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0068] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0069] The following disclosure provides many different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0070] Air Conditioner Working Principle

[0071] Air conditioners execute a refrigeration cycle using a compressor, condenser, expansion valve, and evaporator. The refrigeration cycle involves a series of processes, including compression, condensation, expansion, and evaporation, to cool or heat an indoor space.

[0072] Low-temperature, low-pressure refrigerant enters the compressor, which compresses it into a high-temperature, high-pressure refrigerant gas and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the condenser. The condenser condenses the compressed refrigerant into a liquid phase, and heat is released to the surrounding environment through the condensation process.

[0073] The expansion valve expands the high-temperature, high-pressure liquid refrigerant that condenses in the condenser into a low-pressure liquid refrigerant. The evaporator evaporates the expanded refrigerant in the expansion valve and returns 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.

[0074] The outdoor unit of an air conditioner refers to the part of the refrigeration cycle that includes the compressor and the outdoor heat exchanger. The indoor unit of an air conditioner includes the indoor heat exchanger, and an expansion valve can be provided in either the indoor or outdoor unit.

[0075] 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.

[0076] [This application]

[0077] Reference Figure 1This invention discloses an energy-efficient online control air conditioning unit, which includes an evaporator 1, a condenser 2, an economizer 3, and a compressor 4 connected together to form a refrigeration cycle; the compressor 4 is a centrifugal compressor; a refrigerant circulation system is arranged in the evaporator 1 and the condenser 2 respectively for heat dissipation and utilization, and the refrigerant is water or ethylene glycol solution, etc., forming a centrifugal heat pump unit or a centrifugal chiller unit.

[0078] Evaporator 1 is connected to compressor 4 via compressor suction line 101; condenser 2 is connected to compressor 4 via compressor discharge line 402; condenser 2 is connected to economizer 3 via first main line 203, i.e., first main line 203 is a refrigerant line connecting condenser 2 and economizer 3; evaporator 1 is connected to economizer 3 via second main line 302, i.e., second main line 302 is a refrigerant line connecting evaporator 1 and economizer 3; economizer 3 is connected to compressor 4 via make-up gas line 301.

[0079] The energy-efficient online control air conditioning unit also includes multiple pressure sensors, multiple temperature sensors, a frequency converter 5, and a controller 7. The frequency converter 5 is connected to the compressor 4, the controller 7, and the external power supply 6. The controller 7 controls the power supply to the compressor 4 and provides real-time output power feedback to the controller 7. Each pressure sensor and each temperature sensor is connected to the controller 7 to detect refrigerant pressure and temperature at multiple locations in the refrigeration cycle and transmit this information to the controller 7, such as condenser refrigerant pressure, economizer refrigerant pressure, evaporator refrigerant pressure, discharge pressure, discharge temperature, and subcooling temperature.

[0080] The controller 7 establishes a set of energy conservation and mass conservation equations based on the pressure of each refrigerant, the temperature of each refrigerant, and the real-time output power. Solving the set of equations yields the cooling or heating capacity and unit energy efficiency under the corresponding operating conditions.

[0081] The energy-efficient online control air conditioning unit of this invention detects pressure and temperature at different locations on the refrigerant side, and solves a system of equations based on energy and mass conservation to obtain the cooling capacity or heating capacity and unit energy efficiency. This solves the problems of difficult sensor installation and low detection signal accuracy on the refrigerant side, improving the accuracy of the unit's cooling capacity or heating capacity and unit energy efficiency. Furthermore, the method of calculating cooling capacity or heating capacity and unit energy efficiency based on energy conservation, mass conservation, and real-time operating conditions, as well as the neural network training model, does not rely on historical data of unit operation. This ensures consistent accuracy in the detection of cooling capacity or heating capacity and unit energy efficiency from beginning to end, improving the applicability of real-time energy efficiency monitoring and the consistency of detection results.

[0082] The specific control and principle of the energy-efficient online control air conditioning unit of the present invention will be described in detail below through specific embodiments.

[0083] Reference Figure 1 , Figure 2 , Figure 3 , Figure 4 Each pressure sensor is installed at the exhaust port of the economizer 3, evaporator 1, condenser 2, and compressor 4, respectively, and is used to detect the refrigerant pressure of the economizer, the refrigerant pressure of the evaporator, the refrigerant pressure of the condenser, and the exhaust pressure and transmit them to the controller 7.

[0084] Each temperature sensor is installed on the compressor exhaust pipe 402 and the bottom of the condenser 2, respectively, to detect the exhaust temperature and the subcooling temperature of the refrigerant in the liquid bladder at the bottom of the condenser 2 and transmit the data to the controller 7.

[0085] Real-time acquisition of the unit's cooling or heating capacity includes the following steps:

[0086] S1. Calculate the enthalpy of saturated refrigerant gas at the outlet of evaporator 1 based on the refrigerant pressure in the evaporator.

[0087] S2. Calculate the enthalpy of the superheated refrigerant gas at the exhaust port of compressor 4 based on the exhaust pressure and exhaust temperature;

[0088] S3. Calculate the liquid enthalpy of the subcooled refrigerant at the bottom of condenser 2 based on the subcooling temperature;

[0089] S4. Obtain the enthalpy of the two-phase refrigerant at the inlet of economizer 3 based on the enthalpy of the subcooled refrigerant liquid.

[0090] S5. Calculate the enthalpy of saturated refrigerant liquid at the bottom outlet of economizer 3 based on the refrigerant pressure of the economizer.

[0091] S6. Calculate the enthalpy of saturated refrigerant gas at the top outlet of economizer 3 based on the refrigerant pressure of the economizer.

[0092] S7. Calculate the output power of compressor 4 based on the real-time output power, that is, the output power of the output compressor;

[0093] S8. Based on the enthalpy of the saturated refrigerant gas at the outlet of evaporator 1, the enthalpy of the superheated refrigerant gas at the discharge port of compressor 4, the enthalpy of the subcooled refrigerant liquid at the bottom of condenser 2, the enthalpy of the two-phase refrigerant at the inlet of economizer 3, the enthalpy of the saturated refrigerant liquid at the bottom outlet of economizer 3, the enthalpy of the saturated refrigerant gas at the top outlet of economizer 3, and the compressor output power, establish a set of energy conservation and mass conservation equations and solve them to obtain the refrigerant mass flow rate.

[0094] S9. Calculate the cooling capacity or heating capacity based on the refrigerant mass flow rate.

[0095] In S1, the enthalpy of the saturated refrigerant gas at the outlet of evaporator 1 is calculated using the following formula:

[0096] h1 = f1(A, T)e );

[0097] In the formula, h1 is the enthalpy of the saturated refrigerant gas at the outlet of evaporator 1; the coefficient set A is the fitting coefficient of the refrigerant physical property parameters, which is obtained by fitting the saturated refrigerant gas temperature and enthalpy data through a quadratic regression curve; T e This is the evaporation temperature.

[0098] Evaporation temperature T e It can be calculated using the following formula:

[0099] T e =f2(B, P) e );

[0100] In the formula, the coefficient set B represents the fitting coefficients for the refrigerant's physical properties, obtained by fitting the pressure and temperature data of the refrigerant saturated gas through a quadratic regression curve; P e This refers to the refrigerant pressure in the evaporator.

[0101] In S2, the enthalpy of the superheated refrigerant gas at the discharge port of compressor 4 is calculated using the following formula:

[0102] h2=f3(C,T sd ΔT SH );

[0103] In the formula, h2 is the enthalpy of the superheated refrigerant gas at the discharge port of compressor 4; the coefficient set C is the fitting coefficient of the refrigerant physical property parameters, which is obtained by fitting the superheat, corresponding saturation temperature and enthalpy data of the superheated refrigerant gas through a quadratic regression curve; T sd The saturation temperature of the superheated gas at the discharge port of compressor 4 is calculated using the following formula:

[0104] T sd =f2(B, P) d );

[0105] In the formula, P d This refers to the exhaust pressure.

[0106] ΔT SH The superheat of the superheated gas at the exhaust port of compressor 4 can be calculated using the following formula:

[0107] ΔT SH =T d -T sd ;

[0108] In the formula, T d This refers to the exhaust temperature.

[0109] In S3, the enthalpy of the subcooled refrigerant liquid at the bottom of condenser 2 is calculated using the following formula:

[0110] h3=f4(D,Tsub );

[0111] In the formula, h3 is the enthalpy of the subcooled refrigerant liquid at the bottom of condenser 2; the coefficient set D is the fitting coefficient of the refrigerant physical property parameters, which is obtained by fitting the refrigerant saturated liquid temperature and Korean data through a quadratic regression curve; T sub The subcooling temperature is the temperature of the subcooled refrigerant liquid at the bottom of condenser 2.

[0112] In S4, according to the principle of the refrigeration cycle system, the enthalpy h4 of the two-phase refrigerant at the inlet of the economizer 3 is equal to the enthalpy h3 of the subcooled refrigerant liquid at the bottom of the condenser 2.

[0113] In S5, the enthalpy of the saturated refrigerant liquid at the bottom outlet of economizer 3 is calculated using the following formula:

[0114] h5 = f4(D, T) ec );

[0115] In the formula, h5 is the enthalpy of the saturated refrigerant liquid at the bottom outlet of the economizer 3; the coefficient set D is the fitting coefficient of the refrigerant physical property parameters, which is obtained by fitting the saturated refrigerant liquid temperature and enthalpy data through a quadratic regression curve; T ec The temperature of the saturated liquid refrigerant at the outlet at the bottom of the economizer 3 can be calculated using the following formula:

[0116] T ec =f2(B, P) ec );

[0117] In the formula, P ec For the refrigerant pressure of the economical device.

[0118] In S6, the enthalpy of the saturated refrigerant gas used for makeup gas at the top outlet of economizer 3 is calculated using the following formula:

[0119] h6=f1(A,T ec );

[0120] In the formula, h6 is the enthalpy of the saturated refrigerant gas used for makeup gas at the top outlet of the economizer 3; T ec The temperature of the saturated gas refrigerant at the top outlet of the economizer 3.

[0121] In S7, the compressor output power is calculated using the following formula:

[0122] P = f5(E, P) b );

[0123] In the formula, P is the compressor output power; the coefficient set E is the compressor output power fitting coefficient, which is obtained by fitting the compressor shaft output power during operation and the real-time output power of the compressor and the inverter 5 through a quadratic regression curve; Pb is the real-time output power.

[0124] In this embodiment, the calculation of the saturated refrigerant gas enthalpy at the outlet of evaporator 1, the superheated refrigerant gas enthalpy at the discharge port of compressor 4, the subcooled refrigerant liquid enthalpy at the bottom of condenser 2, the two-phase refrigerant enthalpy at the inlet of economizer 3, the saturated refrigerant liquid enthalpy at the bottom outlet of economizer 3, the saturated refrigerant gas enthalpy at the top outlet of economizer 3, and the compressor output power has no order requirement; that is, the calculation of the saturated refrigerant gas enthalpy at the outlet of evaporator 1, the superheated refrigerant gas enthalpy at the discharge port of compressor 4, the subcooled refrigerant liquid enthalpy at the bottom of condenser 2, the two-phase refrigerant enthalpy at the inlet of economizer 3, the saturated refrigerant liquid enthalpy at the bottom outlet of economizer 3, the saturated refrigerant gas enthalpy at the top outlet of economizer 3, and the compressor output power can be performed in any order.

[0125] In some specific embodiments, refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 The energy-efficient online control air conditioning unit also includes a first electric regulating valve 19, which is installed on the gas supply line 301 and used to adjust the gas supply flow. The first electric regulating valve 19 is connected to the controller 7, and its opening is controlled by the controller 7. The controller 7 is configured with a gas supply state and a non-gas supply state, and determines whether it is in a gas supply state by the state of the first electric regulating valve 19. That is, the first electric regulating valve 19 is open in the gas supply state; the first electric regulating valve 19 is closed in the non-gas supply state.

[0126] When in the gas replenishment state, the refrigerant mass flow rate is calculated based on the saturated refrigerant gas enthalpy at the outlet of evaporator 1, the superheated refrigerant gas enthalpy at the discharge port of compressor 4, the subcooled refrigerant liquid enthalpy at the bottom of condenser 2, the two-phase refrigerant enthalpy at the inlet of economizer 3, the saturated refrigerant liquid enthalpy at the bottom outlet of economizer 3, the saturated refrigerant gas enthalpy at the top outlet of economizer 3, and the compressor output power.

[0127] When in non-recharge state, the economizer 3 does not supply gas to the compressor 4. The refrigerant mass flow rate is calculated based on the saturated refrigerant gas enthalpy at the outlet of the evaporator 1, the superheated refrigerant gas enthalpy at the discharge port of the compressor 4, the subcooled refrigerant liquid enthalpy at the bottom of the condenser 2, and the compressor output power.

[0128] Specifically, based on the pressure and enthalpy diagrams of the gas-supplemented and non-gas-supplemented states, a set of energy and mass conservation equations for the operation of the refrigeration cycle is established.

[0129] In the state of replenishing Qi:

[0130]

[0131] In non-Qi-replenishing state:

[0132] Q m (h2-h3)=P+Q m (h1-h3);

[0133] In the formula, Q m1 Q is the first-stage mass flow rate in a two-stage variable frequency air conditioning unit system. m2 Q is the makeup gas mass flow rate in a two-stage variable frequency air conditioning unit system. m The total mass flow rate in a two-stage variable frequency air conditioning unit system;

[0134] Solving the system of equations, the refrigerant mass flow rate under the gas-fuel condition is:

[0135]

[0136] The refrigerant mass flow rate under non-gas-replenishment conditions is:

[0137] Q m =f9(h1, h2, h3, P);

[0138] After obtaining the refrigerant mass flow rate in the refrigeration cycle system by following the above process, the cooling capacity or heating capacity of the unit system can be calculated based on the refrigerant mass flow rate.

[0139] Specifically, heat pump units:

[0140] Q y =f 12 (h2, h3, Q) m );

[0141] Chiller unit air supply status:

[0142] Q y =f 10 (h1, h5, Q) m );

[0143] Chiller unit in non-air-supply state:

[0144] Q y =f 11 (h1, h3, Q) m );

[0145] In the formula, Q y This refers to the real-time cooling or heating capacity of the cold circulation system.

[0146] In this embodiment, the energy efficiency online control air conditioning unit calculates the cooling or heating capacity based on the chiller's gas supply and non-gas supply states, thereby improving the accuracy of the cooling or heating capacity.

[0147] In some specific embodiments, refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 The energy efficiency online control air conditioning unit also includes a cooling liquid supply pipeline and a cooling heat exchange module; the cooling liquid supply pipeline includes a frequency converter cooling liquid supply pipeline 201 and a motor cooling liquid supply pipeline 202; the cooling heat exchange module is respectively set to the motor 8 and frequency converter 5 of the compressor 4, and is used to cool the motor 8 and frequency converter 5 of the compressor 4; the motor cooling liquid supply pipeline 202 and the frequency converter cooling liquid supply pipeline 201 are respectively connected to the cooling heat exchange module, and are respectively used to provide liquid refrigerant to the cooling heat exchange module for cooling the motor 8 and frequency converter 5 of the compressor.

[0148] The energy efficiency online control air conditioning unit also includes a flow sensor 18, which is connected to the controller 7; the flow sensor 18 and a temperature sensor are respectively installed on the cooling liquid supply pipeline to detect the flow rate and temperature of the cooling liquid refrigerant and transmit them to the controller 7.

[0149] The controller 7 calculates the cooling loss based on the enthalpy of the saturated refrigerant gas at the outlet of the evaporator 1, the enthalpy of the superheated refrigerant gas at the exhaust port of the compressor 4, the enthalpy of the subcooled refrigerant liquid at the bottom of the condenser 2, the enthalpy of the saturated refrigerant liquid at the bottom outlet of the economizer 3, the flow rate of the cooling liquid, and the supply temperature.

[0150] Specifically, heat pump units:

[0151] Q s =f 15 (h2, h3, Q) ms );

[0152] Chiller unit air supply status:

[0153] Q s =f 13 (h1, h5, Q) ms );

[0154] Chiller unit in non-air supply state:

[0155] Q s =f 14 (h1, h3, Q) ms );

[0156] In the formula, Q s This represents the loss of cooling capacity; Q ms The mass flow rate of the refrigerant supplied for cooling can be calculated using the following formula:

[0157] Q ms =f16 (G, T) sup F L );

[0158] In the formula, the coefficient set G represents the fitting coefficients for the refrigerant's physical properties, obtained by fitting the density and temperature data of the saturated refrigerant liquid using a quadratic regression curve; T sup To cool the refrigerant supply temperature, F L The flow rate of the cooling liquid refrigerant.

[0159] Controller 7 obtains the corrected cooling or heating capacity by correcting for cooling loss. Specifically, this is calculated using the following formula:

[0160] Q = f 17 (H, Q) y Q s );

[0161] In the formula, Q is the corrected cooling capacity or heating capacity; the coefficient set H is the cooling capacity or heating capacity correction coefficient of the test unit on the experimental bench, which is obtained by fitting the actual tested cooling capacity or heating capacity when the unit is running on the experimental test bench before leaving the factory with the cooling capacity or heating capacity data calculated by the algorithm embedded in the controller 7 through a quadratic regression curve.

[0162] In this embodiment, the online energy efficiency control air conditioning unit calculates the cooling or heating capacity of the refrigerant used for cooling, and corrects the unit's cooling or heating capacity to improve the accuracy of the unit's cooling or heating capacity, thereby improving the accuracy of the unit's energy efficiency.

[0163] In some specific embodiments, refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 The unit energy efficiency calculation includes the following steps:

[0164] S10. Calculate the unit input power based on the real-time output power;

[0165] S11. Calculate the unit's energy efficiency based on the ratio of the unit's input power to its corrected cooling or heating capacity.

[0166] Of course, in S11, the unit's energy efficiency can also be calculated by the ratio of the unit's input power to its cooling or heating capacity.

[0167] In some specific embodiments, refer to 1. Figure 9The compressor 4 transmits the speed to the controller 7; the controller 7 is equipped with a speed threshold, a duration threshold, and an energy efficiency optimization control module; the controller 7 compares the speed received in real time with the speed received last time. If the change compared with the speed received last time does not exceed the speed threshold, it determines that the unit is in a stable state and times the stable state to obtain the duration of the stable state; the controller 7 compares the duration of the stable state with the duration threshold in real time.

[0168] When the duration of the stable state exceeds the duration threshold, the energy efficiency optimization control module is executed to optimize the unit's energy efficiency.

[0169] If the steady-state duration does not exceed the duration threshold, the energy efficiency optimization control module is not executed; the timing continues; and if the real-time received speed exceeds the speed threshold compared to the previously received speed, the steady-state timing is restarted when the next received speed does not exceed the speed threshold compared to the previous received speed.

[0170] In this embodiment, the energy efficiency online control air conditioning unit performs energy efficiency optimization control under the condition that the compressor 4 is running in a stable state, which not only improves the unit's energy efficiency but also improves the stability of the unit's operation.

[0171] In some specific embodiments, refer to Figure 1 , Figure 10 The energy efficiency online control air conditioning unit also includes a second electric regulating valve 20 and a third electric regulating valve 21, which are respectively installed on the first main pipeline and the second main pipeline, and are used to regulate the refrigerant supply from the condenser 2 to the economizer 3 and the refrigerant supply from the economizer 3 to the evaporator 1; the second electric regulating valve 20 and the third regulating valve are respectively connected to the controller 7, and are controlled by the controller 7 to open or close or adjust the opening degree.

[0172] The energy efficiency optimization and control module includes an optimal energy efficiency acquisition module, which includes:

[0173] S100: Obtain refrigerant pressure from the economizer, condenser, and evaporator;

[0174] S200, Set pressure step size; Obtain multiple pressure combinations by increasing or decreasing the obtained refrigerant pressure of the economizer, condenser, and evaporator by an integer number of pressure steps.

[0175] S300: Calculate the corresponding cooling or heating capacity based on the current unit input power and various pressure combinations; take the maximum value of each calculated cooling or heating capacity as the optimal cooling or heating capacity.

[0176] S400: Adjust the opening of the first electric regulating valve 19, the second electric regulating valve 20, and the third electric regulating valve 21 according to the optimal cooling or heating capacity, so that the unit's cooling or heating capacity reaches or approaches the optimal cooling or heating capacity, and the unit's energy efficiency reaches or approaches the optimal.

[0177] In some specific embodiments, refer to Figure 1 , Figure 9 , Figure 10 Because the compressor 4 of the energy efficiency online control air conditioning unit is a vane compressor, it will experience abnormal vibration, or surge, when the flow rate decreases to a certain level. Surge is very harmful to centrifugal compressor 4.

[0178] The control system is equipped with a surge detection module to determine whether the unit has a surge risk; when the unit has a surge risk, the unit is about to or close to experiencing a surge failure.

[0179] The controller 7 is configured to determine whether the pressure combination corresponding to the optimal cooling capacity or heating capacity has a surge risk through the surge judgment module; and when there is a surge risk, it will sequentially judge whether the corresponding pressure combination has a surge risk based on the size of each cooling capacity calculated by each pressure combination, until a pressure combination without a surge risk appears, and use this pressure combination as the target pressure combination to perform energy efficiency optimization control of the unit.

[0180] When the pressure combination corresponding to the optimal cooling capacity or heating capacity does not have surge conditions, the unit is optimized for energy efficiency control by using the pressure combination corresponding to the optimal cooling capacity or heating capacity as the target pressure combination.

[0181] In some specific embodiments, refer to Figure 1 , Figure 9 , Figure 10 , Figure 11 The energy efficiency optimization control module also includes an electric regulating valve opening control module, which includes:

[0182] S500: Obtain the current opening degree of the first electric regulating valve 19, the second electric regulating valve 20, and the third electric regulating valve 21;

[0183] S600. Calculate the target opening degree of the first electric regulating valve 19, the second electric regulating valve 20, and the third electric regulating valve 21 based on the target pressure combination.

[0184] S700: Calculate the adjustment opening of each electric regulating valve based on the current opening of the first electric regulating valve 19, the second electric regulating valve 20, and the third electric regulating valve 21, and the calculated target opening of the first electric regulating valve 19, the second electric regulating valve 20, and the third electric regulating valve 21, and control each electric regulating valve to adjust its opening accordingly.

[0185] In some specific embodiments, the working process of the unit from startup to later operation is described in detail below:

[0186] (1) Unit start-up phase

[0187] After the unit starts up, the pressure sensor, temperature sensor, and flow sensor 18 arranged in the system collect the pressure, temperature, and flow at each key location in real time, and feed back the collected pressure, temperature, and flow data to the controller 7; the unit's frequency converter 5 feeds back the output power to the controller 7 in real time; the electric regulating valves on each pipeline in the unit also feed back their opening degree to the controller 7 in real time; and the unit's compressor 4 feeds back its speed to the controller 7 in real time.

[0188] (2) Determination of the execution of the unit system cooling capacity (heating capacity) and energy efficiency optimization strategy

[0189] During unit operation, compressor 4 feeds back its speed to controller 7 in real time, recording the duration of the compressor 4 speed when the difference does not exceed the speed threshold and the duration of the stable state. The stable state duration is compared with the duration threshold. If the stable state duration exceeds the duration threshold, the unit is considered to be in a stable state, and the cooling capacity or heating capacity and unit energy efficiency optimization control module is executed. If the stable state duration does not exceed the duration threshold, the unit is considered to be in an unstable state, possibly under loading, unloading, or other unstable operating conditions, and the cooling capacity or heating capacity and unit energy efficiency optimization control module is not executed.

[0190] If it is determined that the cooling or heating capacity and unit energy efficiency optimization control modules will not be executed, the unit system will continue to time the stable state duration and make judgments.

[0191] If it is determined that the cooling capacity or heating capacity and unit energy efficiency optimization control module should be executed, then the control process of the unit energy efficiency optimization control module will be executed.

[0192] In some specific embodiments, the unit's cooling or heating capacity and unit energy efficiency optimization control module mainly includes:

[0193] Each pressure sensor collects real-time refrigerant pressure from the economizer, condenser, and evaporator.

[0194] The pressure combination dataset is determined based on the pressure collected by the sensor and the set calculation pressure step size;

[0195] Calculate the corresponding cooling capacity or heating capacity for each pressure combination dataset to obtain a combined cooling capacity or heating capacity dataset.

[0196] Select the maximum cooling or heating capacity in the dataset of cooling or heating capacity combinations, and determine the corresponding pressure combination as the target pressure combination.

[0197] The electric regulating valves on each pipeline in the unit system provide real-time feedback on their current opening degree; the opening adjustment target is calculated based on the target pressure combination and the current valve opening degree.

[0198] After completing the above actions, controller 7 needs to determine whether the unit's operating state will cause instability, that is, whether the target pressure combination conflicts with the anti-surge control logic in the unit. Depending on the determination result, different actions will be taken:

[0199] The target pressure combination conflicts with the anti-surge control logic in the unit. At this time, the execution of the unit system cooling capacity (heating capacity) and energy efficiency optimization control strategy may cause the unit's operating state to become unstable. Therefore, the subsequent actions are stopped to maintain the unit's operating state unchanged.

[0200] The target pressure combination does not conflict with the anti-surge control logic in the unit. At this time, the subsequent action is executed to adjust the opening of the electric regulating valve to the opening adjustment target.

[0201] After the unit's cooling or heating capacity and unit energy efficiency optimization control module are executed, system stability monitoring must be performed.

[0202] Once the unit's cooling or heating capacity and energy efficiency optimization control module are executed, the adjusted state is maintained to keep the unit running for a preset time, and the unit's operating status is continuously monitored during the operation.

[0203] If no abnormal alarm occurs in the unit within the preset time period of the cooling capacity or heating capacity and unit energy efficiency optimization control module, the optimization of the cooling capacity or heating capacity and unit energy efficiency is completed.

[0204] If an abnormal alarm occurs in the unit within the preset time period of the cooling or heating capacity and unit energy efficiency optimization control strategy, the corresponding preset control logic in the unit needs to be executed according to the alarm category to resolve the alarm problem.

[0205] In some specific embodiments, refer to Figure 1Regardless of the stage of unit operation, all pressure sensors, temperature sensors, and flow sensors 18 in the system are in continuous operation. Specifically, the first pressure sensor 11, the second pressure sensor 12, the third pressure sensor 13, and the fourth pressure sensor 14 collect real-time data on evaporator refrigerant pressure, condenser refrigerant pressure, economizer refrigerant pressure, and compressor discharge pressure; the first temperature sensor 15, the second temperature sensor 16, and the third temperature sensor 17 collect real-time data on coolant supply temperature, compressor discharge temperature, and flow rate in the liquid bladder at the bottom of the condenser 2. The subcooling temperature of the refrigerant after cooling; the flow sensor 18 collects the refrigerant flow rate of the cooling liquid in real time; the first electric regulating valve 19, the second electric regulating valve 20, and the third electric regulating valve 21 provide real-time feedback on their current opening degree; the frequency converter 5 provides feedback on its real-time output power; the compressor 4 provides real-time feedback on its operating speed; the time threshold is set to 120s in this scheme; the pressure step is set according to the actual situation, and is set to 1kPa in this scheme description; the unit's cooling capacity or heating capacity and the maintenance operation time after the unit's energy efficiency optimization are set according to the actual situation, and are set to 30s in this scheme description.

[0206] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0207] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An energy-efficient online control air conditioning unit, comprising a centrifugal compressor, a condenser, an economizer, and an evaporator connected together to form a refrigeration cycle system, characterized in that, It also includes multiple pressure sensors, multiple temperature sensors, frequency converters, and controllers; The frequency converter is connected to the compressor and the controller respectively, and feeds back the real-time output power of the compressor to the controller; each of the pressure sensors and each of the temperature sensors are respectively set at different positions in the refrigeration cycle system and connected to the controller, for detecting the refrigerant pressure and temperature at each position and transmitting them to the controller; The controller establishes a set of energy conservation and mass conservation equations based on the refrigerant pressure, temperature, and real-time output power to obtain the cooling or heating capacity and unit energy efficiency under the corresponding operating conditions.

2. The energy efficiency online control air conditioning unit according to claim 1, characterized in that, Each of the pressure sensors is respectively installed on the exhaust port of the economizer, the evaporator, the condenser, and the compressor, and is used to detect the refrigerant pressure of the economizer, the refrigerant pressure of the evaporator, the refrigerant pressure of the condenser, and the exhaust pressure. Each of the temperature sensors is respectively installed in the exhaust pipe and at the bottom of the condenser, and is used to detect the exhaust temperature and the subcooling temperature, respectively; Obtaining the cooling or heating capacity includes the following steps: S1. Calculate the enthalpy of the saturated refrigerant gas at the outlet of the evaporator based on the refrigerant pressure of the evaporator; S2. Calculate the enthalpy of the superheated refrigerant gas at the exhaust port of the compressor based on the exhaust pressure and the exhaust temperature; S3. Calculate the liquid enthalpy of the subcooled refrigerant at the bottom of the condenser based on the subcooling temperature; S4. Obtain the enthalpy value of the two-phase refrigerant at the inlet of the economizer based on the enthalpy value of the subcooled refrigerant liquid; S5. Calculate the saturated refrigerant liquid enthalpy at the bottom outlet of the economizer based on the refrigerant pressure of the economizer. S6. Calculate the enthalpy of the saturated refrigerant gas at the top outlet of the economizer based on the refrigerant pressure of the economizer. S7. Calculate the output power of the compressor based on the real-time output power, i.e., the compressor output power; S8. Based on the above enthalpy values ​​and the compressor output power, establish an energy conservation and mass conservation equation set to obtain the refrigerant mass flow rate; S9. Calculate the cooling capacity or heating capacity based on the refrigerant mass flow rate.

3. The energy efficiency online control air conditioning unit according to claim 2, characterized in that, The controller is configured with a gas replenishment state and a non-gas replenishment state; When in the gas replenishment state, the refrigerant mass flow rate is calculated based on the saturated refrigerant gas enthalpy at the outlet of the evaporator, the superheated refrigerant gas enthalpy at the discharge port of the compressor, the subcooled refrigerant liquid enthalpy at the bottom of the condenser, the two-phase refrigerant enthalpy at the inlet of the economizer, the saturated refrigerant liquid enthalpy at the bottom outlet of the economizer, the saturated refrigerant gas enthalpy at the top outlet of the economizer, and the compressor output power. When in the non-refilled gas state, the refrigerant mass flow rate is calculated based on the saturated refrigerant gas enthalpy at the outlet of the evaporator, the superheated refrigerant gas enthalpy at the exhaust port of the compressor, the subcooled refrigerant liquid enthalpy at the bottom of the condenser, and the compressor output power.

4. The energy efficiency online control air conditioning unit according to claim 3, characterized in that, It also includes a cooling liquid supply line and a flow sensor; one end of the cooling liquid supply line is connected to the condenser to provide liquid refrigerant for cooling; the flow sensor and the temperature sensor are respectively installed on the cooling liquid supply line to detect the flow rate and temperature of the cooling liquid refrigerant and transmit them to the controller. The cooling capacity loss is calculated based on the enthalpy of the saturated refrigerant gas at the outlet of the evaporator, the enthalpy of the superheated refrigerant gas at the discharge port of the compressor, the enthalpy of the subcooled refrigerant liquid at the bottom of the condenser, the enthalpy of the saturated refrigerant liquid at the bottom outlet of the economizer, the flow rate of the cooling liquid refrigerant, and the temperature of the cooling liquid refrigerant. The cooling capacity or heating capacity is obtained by correcting the cooling loss to obtain the corrected cooling capacity or heating capacity.

5. The energy efficiency online control air conditioning unit according to claim 4, characterized in that, The unit energy efficiency calculation includes the following steps: S10. Calculate the unit input power based on the real-time output power; S11, The ratio of the unit's input power to the corrected cooling capacity or heating capacity is the unit's energy efficiency.

6. The energy efficiency online control air conditioning unit according to claim 4, characterized in that, The calculations of the enthalpy values ​​of the saturated refrigerant gas, the superheated refrigerant gas, the subcooled refrigerant liquid, the two-phase refrigerant, the enthalpy value of the saturated refrigerant liquid, the compressor output power, the unit input power, the cooling loss, and the corrected cooling capacity or heating capacity are all calculated by formulas obtained by fitting the test data of the changes to a quadratic regression curve.

7. The energy-efficient online control air conditioning unit according to any one of claims 2 to 5, characterized in that, The compressor transmits its rotational speed to the controller; the controller is equipped with a rotational speed threshold, a duration threshold, and an energy efficiency optimization control module; when the change in rotational speed does not exceed the rotational speed threshold, it is determined to be in a stable state, and a stable state timer is started; the stable state timer is compared with the duration threshold. When the steady-state time exceeds the duration threshold, the energy efficiency optimization control module is executed; otherwise, the energy efficiency optimization control module is not executed.

8. The energy efficiency online control air conditioning unit according to claim 7, characterized in that, The energy efficiency optimization and control module includes an optimal energy efficiency acquisition module, which includes: Obtain the refrigerant pressure of the economizer, the refrigerant pressure of the condenser, and the refrigerant pressure of the evaporator; Set the pressure step size; obtain multiple pressure combinations by increasing or decreasing the refrigerant pressure of the economizer, the refrigerant pressure of the condenser, and the refrigerant pressure of the evaporator by an integer multiple of the pressure step size; Multiple cooling or heating capacities are calculated based on the current unit input power and various pressure combinations, and the maximum value among them is taken as the optimal cooling or heating capacity.

9. The energy efficiency online control air conditioning unit according to claim 8, characterized in that, The controller is equipped with a surge detection module to determine whether the unit has a surge risk; and is configured to use the surge detection module to determine whether the pressure combination corresponding to the optimal cooling capacity or heating capacity has a surge risk. If so, the pressure combination corresponding to each of the cooling or heating capacities is judged in descending order to determine whether there is a surge risk, until a pressure combination without surge risk is found, and it is set as the target pressure combination. If not, then the pressure combination corresponding to the optimal cooling capacity or heating capacity is the target pressure combination.

10. The energy efficiency online control air conditioning unit according to claim 9, characterized in that, It also includes a first electric regulating valve, a second electric regulating valve, and a third electric regulating valve, which are respectively connected to the controller and respectively installed on the gas supply line, the connection line between the condenser and the economizer, and the connection line between the evaporator and the economizer; The energy efficiency optimization control module also includes an electric regulating valve opening control module, which includes: Obtain the current opening degree of the first electric regulating valve, the second electric regulating valve, and the third electric regulating valve; Calculate the target opening degree of the first electric regulating valve, the second electric regulating valve, and the third electric regulating valve based on the target pressure combination; The adjustment opening of the first electric regulating valve, the second electric regulating valve, and the third electric regulating valve is calculated based on the current opening and the target opening.

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