Refrigerator operation control method and controller, refrigeration system, storage medium

Abstract

The embodiment of the application provides a refrigeration machine operation control method and controller, a refrigeration system and a storage medium, and relates to the technical field of refrigeration. The method comprises the following steps: obtaining a candidate pressure ratio characteristic curve and a candidate isentropic compression efficiency curve; obtaining a candidate performance index combination according to an evaporator temperature, a condenser temperature and a candidate rotating speed screening curve; calculating a target isentropic compression efficiency according to the evaporator temperature, the condenser temperature and the candidate isentropic compression efficiency curve; determining an isentropic compression refrigeration energy efficiency according to the evaporator temperature, the condenser temperature, a refrigerant subcooling degree of the condenser and a refrigerant superheating degree of the evaporator; obtaining a predicted refrigeration energy efficiency corresponding to the candidate performance index combination by weighted summation of a system operation efficiency, the isentropic compression refrigeration energy efficiency and the target isentropic compression efficiency; and adjusting the refrigeration machine according to the candidate performance index combination corresponding to the maximum predicted refrigeration energy efficiency. The embodiment of the application can improve the accuracy of refrigeration machine operation control.

Description

Technical Field

[0001] This application relates to the field of refrigeration technology, and in particular to a refrigeration machine operation control method and controller, refrigeration system, and storage medium. Background Technology

[0002] A refrigeration unit is a device that transfers heat from a cold object to a hot object, thereby cooling or maintaining a low-temperature environment. It is a component of a refrigeration system, which may include a refrigeration unit, cooling water pump, heat exchanger, and cold storage equipment. To optimize the performance of a refrigeration system, such as improving energy efficiency, it is usually necessary to adjust the refrigeration unit within the system.

[0003] Currently, the chiller is typically regulated by controlling its external state (such as the temperature of the cooling water output by the chiller). However, this method struggles to understand the relationship between the chiller's internal state (such as the chiller's rotational speed) and the overall performance of the refrigeration system. It is difficult to precisely adjust the chiller to a state that is conducive to the operation of the refrigeration system, meaning that the operation control of the chiller is not precise enough.

[0004] Therefore, improving the accuracy of refrigeration unit operation control has become an urgent technical problem to be solved. Summary of the Invention

[0005] The main objective of this application is to provide a method for controlling the operation of a refrigeration machine, as well as a controller, a refrigeration system, and a storage medium, in order to improve the accuracy of the operation control of the refrigeration machine.

[0006] To achieve the above objectives, a first aspect of this application provides a method for controlling the operation of a refrigeration unit, the method comprising:

[0007] Acquire candidate pressure ratio characteristic curves and candidate isentropic compression efficiency curves of the refrigeration unit in the refrigeration system; wherein, the candidate pressure ratio characteristic curve is used to indicate the correlation between the ratio of the evaporator pressure to the condenser pressure of the refrigeration unit and the performance index of the compressor, and the candidate isentropic compression efficiency curve is used to indicate the correlation between the isentropic compression efficiency of the compressor and the performance index of the compressor, wherein the performance index includes guide vane opening degree and compressor speed;

[0008] Obtain the evaporator temperature of the evaporator and the condenser temperature of the condenser;

[0009] Based on the evaporator temperature, the condenser temperature, and the candidate rotation speed, the candidate pressure ratio characteristic curves are screened to obtain the target pressure ratio characteristic curve. The combination of the guide vane opening of the target pressure ratio characteristic curve and the candidate rotation speed is determined as the candidate performance index combination.

[0010] The isentropic compression efficiency is calculated based on the evaporator temperature, the condenser temperature, and the candidate isentropic compression efficiency curve corresponding to the candidate performance index combination, to obtain the target isentropic compression efficiency corresponding to the candidate performance index combination.

[0011] The isentropic compression refrigeration efficiency is determined based on the evaporator temperature, the condenser temperature, the refrigerant subcooling of the condenser, and the refrigerant superheat of the evaporator.

[0012] The system operating efficiency of the refrigeration system is obtained, and the predicted refrigeration efficiency corresponding to the candidate performance index combination is obtained by weighted summation based on the system operating efficiency, the isentropic compression refrigeration efficiency and the target isentropic compression efficiency.

[0013] The equipment parameters of the refrigeration unit are adjusted based on the candidate performance index combination corresponding to the largest predicted refrigeration energy efficiency.

[0014] To achieve the above objectives, a second aspect of this application provides a controller, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the method described in the first aspect.

[0015] To achieve the above objectives, a third aspect of this application provides a refrigeration system, the refrigeration system comprising:

[0016] The controller, chiller, and cold storage device described in the second aspect above; the controller is communicatively connected to the chiller, and the cold storage device is physically connected to the chiller.

[0017] To achieve the above objectives, a fourth aspect of the present application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method described in the first aspect.

[0018] The refrigeration machine operation control method, controller, refrigeration system, and storage medium proposed in this application obtain candidate pressure ratio characteristic curves and candidate isentropic compression efficiency curves of the refrigeration machine. This allows for the determination of the correlation between the internal parameters of the refrigeration machine (such as the compressor guide vane opening and compressor speed) and the operating states of the evaporator and condenser, as well as the compressor's isentropic compression efficiency. This enables the analysis of the impact of the refrigeration machine's internal operating parameters on system performance (such as refrigeration energy efficiency). The evaporator temperature and condenser temperature are obtained, and candidate pressure ratio characteristic curves are screened based on these temperatures and candidate speeds to obtain the target pressure ratio characteristic curve. The combination of guide vane opening and candidate speed of the target pressure ratio characteristic curve is then determined as the candidate performance index combination. This provides a precise basis for adjusting the internal parameters (i.e., the combination of guide vane opening and candidate speed) corresponding to the current operating state of the refrigeration machine, offering a practical reference for subsequent refrigeration machine operation control. Then, based on the evaporator temperature, condenser temperature, and the candidate isentropic compression efficiency curve corresponding to the candidate performance index combination, the isentropic compression efficiency is calculated to obtain the target isentropic compression efficiency corresponding to the candidate performance index combination. Based on the evaporator temperature, condenser temperature, refrigerant subcooling in the condenser, and refrigerant superheat in the evaporator, the isentropic compression refrigeration efficiency is determined. Furthermore, a weighted sum is performed based on the system operating efficiency of the refrigeration system, the isentropic compression refrigeration efficiency, and the target isentropic compression efficiency to obtain the predicted refrigeration efficiency corresponding to the candidate performance index combination. In this way, the impact of the refrigeration unit's internal parameters (i.e., the candidate performance index combination) on refrigeration efficiency can be clearly quantified in conjunction with the overall state of the refrigeration system to which the refrigeration unit belongs. Then, by selecting the candidate performance index combination corresponding to the highest predicted refrigeration efficiency, the refrigeration unit is adjusted, thereby optimizing the refrigeration efficiency. In this way, compared to directly adjusting the refrigeration unit based on its external state (such as the water temperature output by the refrigeration unit), this application understands the relationship between the refrigeration unit's internal parameters and energy efficiency, and thus can accurately adjust the refrigeration unit's operating state based on the internal parameters that the operator can actually set, thereby improving the accuracy of refrigeration unit operation control. Attached Figure Description

[0019] Figure 1 This is a flowchart of the chiller operation control method provided in the embodiments of this application;

[0020] Figure 2 This is a schematic diagram of the compressor characteristic curve of the refrigeration machine provided in the embodiments of this application;

[0021] Figure 3 yes Figure 1 The flowchart for step 101 in the document;

[0022] Figure 4 yes Figure 1The flowchart for step 103 in the document;

[0023] Figure 5 yes Figure 4 The flowchart for step 303 in the document;

[0024] Figure 6 yes Figure 1 The flowchart for step 105 in the document;

[0025] Figure 7 yes Figure 6 The flowchart for step 502 in the document;

[0026] Figure 8 yes Figure 1 The flowchart for step 106 in the document;

[0027] Figure 9 This is a schematic diagram showing the relationship between temperature and specific entropy in the compression refrigeration process of a refrigerator provided in an embodiment of this application;

[0028] Figure 10 yes Figure 9 A magnified view of region A in the diagram;

[0029] Figure 11 This is a schematic diagram of the hardware structure of the controller provided in the embodiments of this application. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0031] It should be noted that although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device or the order in the flowchart. The terms "first," "second," etc., in the specification, claims, and the aforementioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0033] First, let's analyze some of the terms used in this application:

[0034] Air compressor inlet guide vanes (IGVs): These are key adjustment components of the compressor, typically installed at the compressor inlet. By changing the angle of the guide vanes, the direction of the intake airflow can be guided.

[0035] Guide vane opening: This parameter characterizes the position of the guide vanes during the flow regulation process of the compressor. The value of the guide vane opening is the minimum distance between the outlet or inlet edges of adjacent guide vanes.

[0036] Mass flow rate: refers to the mass of fluid passing through the effective cross-section of a closed pipe or open channel per unit time.

[0037] Stagnation density is a density parameter in gas dynamics that describes the density of airflow when its velocity drops to zero during adiabatic stagnation (i.e., isentropic) process.

[0038] To optimize the energy efficiency of a refrigeration system, it is necessary to adjust the chiller within the system. However, in current refrigeration systems, the adjustment and control of the internal parameters of the chiller are not directly controlled by the refrigeration system. Typically, the chiller adjusts itself based solely on the system's chilled water and cooling water temperatures at the equipment boundaries, aiming to control the chilled water outlet temperature. The chiller's control system is not integrated with the refrigeration system's control system, and cannot share complex information about system operation. Therefore, the chiller may not achieve the optimal operating state for the refrigeration system. Furthermore, the refrigeration system cannot access detailed information about the chiller's internal operations, nor can it optimize and adjust the chiller's operating parameters according to different system operating conditions. Therefore, current chiller operation control is not precise enough.

[0039] Based on this, embodiments of this application provide a refrigeration machine operation control method, controller, refrigeration system, and storage medium, aiming to improve the accuracy of refrigeration machine operation control.

[0040] The chiller operation control method, controller, refrigeration system, and storage medium provided in this application are specifically described through the following embodiments. First, the chiller operation control method in this application embodiment is described.

[0041] Figure 1 This is an optional flowchart of the chiller operation control method provided in the embodiments of this application. Figure 1 The method may include, but is not limited to, steps 101 to 107.

[0042] Step 101: Obtain the candidate pressure ratio characteristic curve and the candidate isentropic compression efficiency curve of the refrigeration machine in the refrigeration system; wherein, the candidate pressure ratio characteristic curve is used to indicate the correlation between the ratio of the pressure of the evaporator and the pressure of the condenser of the refrigeration machine and the performance index of the compressor, and the candidate isentropic compression efficiency curve is used to indicate the correlation between the isentropic compression efficiency of the compressor and the performance index of the compressor, including the guide vane opening degree and the compressor speed.

[0043] Step 102: Obtain the evaporator temperature of the evaporator and the condenser temperature of the condenser;

[0044] Step 103: Based on the evaporator temperature, condenser temperature, and candidate rotation speed, the candidate pressure ratio characteristic curve is screened to obtain the target pressure ratio characteristic curve. The combination of the guide vane opening and the candidate rotation speed of the target pressure ratio characteristic curve is determined as the candidate performance index combination.

[0045] Step 104: Calculate the isentropic compression efficiency based on the evaporator temperature, condenser temperature, and the candidate isentropic compression efficiency curve corresponding to the candidate performance index combination, and obtain the target isentropic compression efficiency corresponding to the candidate performance index combination.

[0046] Step 105: Determine the isentropic compression refrigeration efficiency based on the evaporator temperature, condenser temperature, refrigerant subcooling in the condenser, and refrigerant superheat in the evaporator.

[0047] Step 106: Obtain the system operating efficiency of the refrigeration system, and perform a weighted summation based on the system operating efficiency, isentropic compression refrigeration efficiency and target isentropic compression efficiency to obtain the predicted refrigeration efficiency corresponding to the candidate performance index combination.

[0048] Step 107: Adjust the equipment parameters of the refrigeration unit according to the candidate performance index combination corresponding to the maximum predicted refrigeration energy efficiency.

[0049] The beneficial effects of this application's embodiments include, but are not limited to: by acquiring the candidate pressure ratio characteristic curve and candidate isentropic compression efficiency curve of the refrigeration unit, the correlation between the internal parameters of the refrigeration unit (such as the compressor's guide vane opening and compressor speed) and the unit's operating status, such as the pressure of the evaporator and condenser and the compressor's isentropic compression efficiency, can be obtained. This allows for the analysis of the impact of the refrigeration unit's internal operating parameters on system performance (such as refrigeration energy efficiency). The evaporator temperature of the evaporator and the condenser temperature of the condenser are acquired, and the candidate pressure ratio characteristic curve is screened based on the evaporator temperature, condenser temperature, and candidate speed to obtain the target pressure ratio characteristic curve. The combination of the guide vane opening and candidate speed of the target pressure ratio characteristic curve is determined as the candidate performance index combination. This allows for the precise acquisition of the internal parameters (i.e., the combination of guide vane opening and candidate speed) corresponding to the current operating state of the refrigeration unit, providing a practical and feasible basis for subsequent refrigeration unit operation control. Then, based on the evaporator temperature, condenser temperature, and the candidate isentropic compression efficiency curve corresponding to the candidate performance index combination, the isentropic compression efficiency is calculated to obtain the target isentropic compression efficiency corresponding to the candidate performance index combination. Based on the evaporator temperature, condenser temperature, refrigerant subcooling in the condenser, and refrigerant superheat in the evaporator, the isentropic compression refrigeration efficiency is determined. Furthermore, a weighted sum is performed based on the system operating efficiency of the refrigeration system, the isentropic compression refrigeration efficiency, and the target isentropic compression efficiency to obtain the predicted refrigeration efficiency corresponding to the candidate performance index combination. In this way, the impact of the refrigeration unit's internal parameters (i.e., the candidate performance index combination) on refrigeration efficiency can be clearly quantified in conjunction with the overall state of the refrigeration system to which the refrigeration unit belongs. Then, by selecting the candidate performance index combination corresponding to the highest predicted refrigeration efficiency, the refrigeration unit is adjusted, thereby optimizing the refrigeration efficiency. In this way, compared to directly adjusting the refrigeration unit based on its external state (such as the water temperature output by the refrigeration unit), the embodiments of this application can understand the relationship between the refrigeration unit's internal parameters and energy efficiency, and thus can accurately adjust the refrigeration unit's operating state based on the internal parameters that the operator can actually set, thereby improving the accuracy of refrigeration unit operation control.

[0050] In step 101 of some embodiments, the refrigeration system is a system used to transfer heat to achieve cooling and temperature reduction functions. The refrigeration system includes a chiller. In another embodiment, the refrigeration system may also include other equipment besides the chiller, such as chilled water pumps, cooling water pumps, cooling towers, heat exchangers, cold storage devices, regulating valves, and pipes. This application does not limit the connection method between the above-mentioned equipment.

[0051] In some embodiments, the refrigeration unit includes a compressor, an evaporator, and a condenser. Specifically, the compressor may be a refrigeration centrifugal compressor. The compressor characteristic curves of the compressor may include candidate pressure ratio characteristic curves and candidate isentropic compression efficiency curves. In some embodiments, there may be multiple candidate pressure ratio characteristic curves and multiple candidate isentropic compression efficiency curves. The candidate pressure ratio characteristic curve is a curve showing the pressure ratio as a function of the flow coefficient. Here, the pressure ratio refers to the ratio between the saturation pressures of the evaporator and the condenser. The candidate isentropic compression efficiency curve is a curve showing the isentropic compression efficiency as a function of the flow coefficient. When any parameter in the compressor's inlet guide vane (IGV) opening degree and compressor speed is different, the candidate pressure ratio characteristic curve (or candidate isentropic compression efficiency curve) will also be different.

[0052] Please see Figure 2 In some embodiments, when the compressor speed of the refrigeration centrifugal compressor is speed N1, and the guide vane openings are IGV1, IGV2, and IGVx respectively, the candidate pressure ratio characteristic curve and the candidate isentropic compression efficiency curve are as follows: Figure 2 As shown. It should be noted that the solid curve represents the candidate pressure ratio characteristic curve, meaning the ordinate of this curve is the pressure ratio (p2 / p1). The dashed curve represents the candidate isentropic compression efficiency curve, meaning the ordinate of this curve is the isentropic compression efficiency (p2 / p1). The horizontal axis of both the candidate pressure ratio characteristic curve and the candidate isentropic compression efficiency curve is the flow coefficient. ).

[0053] Specifically, in Figure 2 In the diagram, the solid green line represents the candidate pressure ratio characteristic curve when the guide vane opening is IGV1 (e.g., IGV1 = 100%), the solid blue line represents the candidate pressure ratio characteristic curve when the guide vane opening is IGVx, and the solid orange line represents the candidate pressure ratio characteristic curve when the guide vane opening is IGV2 (e.g., IGV2 = 70%). The dashed green line represents the candidate isentropic compression efficiency curve when the guide vane opening is IGV1, the dashed blue line represents the candidate isentropic compression efficiency curve when the guide vane opening is IGVx, and the dashed orange line represents the candidate isentropic compression efficiency curve when the guide vane opening is IGV2.

[0054] In step 102 of some embodiments, the evaporator temperature can be the saturation temperature of the evaporator, and the condenser temperature can be the saturation temperature of the condenser.

[0055] In step 103 of some embodiments, the flow coefficient and pressure ratio can be calculated based on the evaporator temperature and condenser temperature, respectively. Then, based on the coordinate points formed by the flow coefficient and pressure ratio, a curve matching the coordinates is found among multiple candidate pressure ratio characteristic curves corresponding to the candidate rotational speed. This candidate pressure ratio characteristic curve is then used as the target pressure ratio characteristic curve. For example, assuming the candidate rotational speed of the compressor is speed N1 and the flow coefficient is... And the pressure ratio is (p2 / p1)x, then, based on Figure 2 It can be seen that the coordinate point formed by the flow coefficient and the pressure ratio lies on the blue solid line curve (that is, the candidate pressure ratio characteristic curve when the guide vane opening is IGVx). In this case, the guide vane opening in the candidate performance index combination is IGVx, and the candidate rotational speed is N1, that is, the value of the candidate performance index combination is (IGVx, N1).

[0056] In step 104 of some embodiments, the flow coefficient can be calculated based on the evaporator temperature and condenser temperature, and then used as the abscissa. The value of the ordinate (i.e., isentropic compression efficiency) of the flow coefficient on the candidate isentropic compression efficiency curve corresponding to the candidate performance index combination is used as the target isentropic compression efficiency. For example, as in the previous example, assuming the candidate speed of the compressor is speed N1, and the flow coefficient is... After obtaining the candidate performance index combination as (IGVx, N1), based on Figure 2 It can be seen that the flow coefficient can be... The ordinate of the candidate isentropic compression efficiency curve (i.e., the blue dashed curve) when the guide vane opening is IGVx. The target is entropy compression efficiency.

[0057] In some embodiments, the meaning and function of isentropic compression refrigeration efficiency in step 105 can be found in the detailed description of step 506 below, and will not be repeated here.

[0058] In step 106 of some embodiments, the energy efficiency of the refrigerant cycle system (i.e., the refrigeration system) can be obtained by multiplying the isentropic compression refrigeration efficiency and the target isentropic compression efficiency. Then, the weighted sum of the refrigerant cycle system energy efficiency and the system operating efficiency is used as the predicted refrigeration energy efficiency. Specifically, the system operating efficiency includes inverter efficiency, motor efficiency, and bearing transmission efficiency. In some embodiments, the predicted refrigeration energy efficiency is defined as follows:

[0059] ,

[0060] In the formula, This indicates the predicted cooling energy efficiency; It represents the energy efficiency of the refrigerant cycle system, which is the product of the isentropic compression refrigeration energy efficiency and the target isentropic compression efficiency; Indicates motor efficiency; Indicates the inverter efficiency; This indicates the bearing transmission efficiency.

[0061] In step 107 of some embodiments, after obtaining the predicted cooling energy efficiency, the highest predicted cooling energy efficiency is selected, and the compressor speed and guide vane opening of the refrigerator are adjusted to the candidate performance index combination corresponding to the highest predicted cooling energy efficiency to improve the cooling energy efficiency. Specifically, a speed (e.g., a candidate speed) can be selected first to calculate a guide vane opening (also called IGV opening); then different speeds are selected, and the IGV opening at different speeds is calculated respectively. Each speed and IGV opening corresponds to a cooling efficiency (i.e., predicted cooling energy efficiency). The candidate performance index combination corresponding to the highest predicted cooling energy efficiency is selected as the optimized performance index combination, and then the refrigerator is adjusted according to the optimized performance index combination.

[0062] Please see Figure 3 In some embodiments, step 101 may include, but is not limited to, steps 201 to 205:

[0063] Step 201: Obtain the initial pressure ratio characteristic curve and the initial isentropic compression efficiency curve of the refrigerator in the refrigeration system; wherein, the first coordinate of the initial pressure ratio characteristic curve is the first refrigeration temperature, and the first coordinate of the initial isentropic compression efficiency curve is the second refrigeration temperature.

[0064] Step 202: Obtain the impeller diameter parameters and refrigerant type parameters of the refrigeration unit;

[0065] Step 203: Input the impeller diameter parameter, refrigerant type parameter, and first refrigeration temperature into a preset temperature-flow coefficient conversion function to calculate the flow coefficient and obtain the first flow coefficient; wherein, the temperature-flow coefficient conversion function is used to characterize the relationship between temperature and flow coefficient;

[0066] Step 204: Calculate the flow coefficient by inputting the impeller diameter parameter, refrigerant type parameter, and second refrigeration temperature into the temperature-flow coefficient conversion function to obtain the second flow coefficient;

[0067] Step 205: Update the first coordinate of the initial pressure ratio characteristic curve according to the first flow coefficient to obtain the candidate pressure ratio characteristic curve, and update the first coordinate of the initial isentropic compression efficiency curve according to the second flow coefficient to obtain the candidate isentropic compression efficiency curve.

[0068] The advantage of this embodiment lies in acquiring the initial pressure ratio characteristic curve and initial isentropic compression efficiency curve of the refrigeration unit, and calculating the first flow coefficient (or second flow coefficient) based on impeller diameter parameters, refrigerant type parameters, and a preset temperature-flow coefficient conversion function inputted at the first (or second) refrigeration temperature. This dynamically converts the temperature coordinates in the initial curves into flow coefficient coordinates, thus adapting to the differences in physical characteristics (such as impeller size) and operating conditions (such as refrigerant type) of different refrigeration units. Then, the first coordinates of the initial pressure ratio characteristic curve and the initial isentropic compression efficiency curve are updated according to the calculated first and second flow coefficients, respectively, to obtain candidate pressure ratio characteristic curves and candidate isentropic compression efficiency curves. This normalizes the above curves, simplifies the subsequent calculation process, provides more accurate data for refrigeration unit operation control, and thus improves the accuracy of refrigeration unit operation control.

[0069] In step 201 of some embodiments, it should be noted that both the initial pressure ratio characteristic curve and the initial isentropic compression efficiency curve have a first coordinate (x-axis) and a second coordinate (y-axis). In some embodiments, the x-axis of the initial pressure ratio characteristic curve is the cooling temperature, and the y-axis is the pressure ratio. The x-axis of the initial isentropic compression efficiency curve is the cooling temperature, and the y-axis is the isentropic compression efficiency. It should be noted that the first cooling temperature is a specific value of the x-axis of the initial pressure ratio characteristic curve, and the second cooling temperature is a specific value of the x-axis of the initial isentropic compression efficiency curve.

[0070] In step 202 of some embodiments, the impeller diameter parameter refers to the diameter of the compressor impeller in the refrigeration machine. It should be noted that the impeller is the core component of the compressor that accelerates and pressurizes the gas, mainly by using high-speed rotation to give the gas kinetic energy and convert it into pressure energy. The refrigerant type parameter can specifically be the specific heat capacity of the refrigerant, expressed in kilojoules per kilogram of Kelvin (kJ / (kg·K)).

[0071] In some embodiments, it should be noted that the refrigerant (also known as a cooling medium) is the working medium in a refrigeration system specifically used for transferring heat. Specifically, the refrigerant in a refrigeration system may include tetrafluoroethane (R134a), or other types of refrigerants.

[0072] In step 203 of some embodiments, the first flow coefficient is a flow coefficient calculated based on a first cooling temperature. In some embodiments, the temperature-flow coefficient conversion function is shown in the following formula:

[0073] ,

[0074] In the formula, Indicates the flow coefficient (e.g., the first flow coefficient or the second flow coefficient). This indicates mass flow rate, and the unit can be kilograms per second (kg / s). This indicates the import stagnation density, and the unit can be kilograms per cubic meter (kilograms per cubic meter). ); Indicates the stagnation coefficient; This indicates the impeller tip diameter (i.e., the impeller diameter parameter). Indicates the type of refrigerant; This indicates the inlet stagnation temperature, and the unit can be degrees Celsius. ); Indicates the isentropic compression coefficient; This indicates the import stagnation pressure, and the unit can be kilopascals (kPa).

[0075] In step 204 of some embodiments, the second flow coefficient is a flow coefficient calculated based on the second cooling temperature.

[0076] In step 205 of some embodiments, a candidate pressure ratio characteristic curve is obtained by converting the first coordinate (x-axis) of the initial pressure ratio characteristic curve from the first refrigeration temperature to the first flow coefficient. Similarly, a candidate isentropic compression efficiency curve is obtained by converting the x-axis of the initial isentropic compression efficiency curve from the second refrigeration temperature to the second flow coefficient.

[0077] Please see Figure 4 In some embodiments, the coordinates of the candidate pressure ratio characteristic curve include the flow coefficient and the pressure ratio, where the pressure ratio is the ratio of the pressure of the evaporator to the pressure of the condenser.

[0078] Step 103 may include, but is not limited to, steps 301 to 304:

[0079] Step 301: Determine the evaporator saturation pressure based on the evaporator temperature and the preset temperature-pressure relationship curve, and determine the condenser saturation pressure based on the condenser temperature and the temperature-pressure relationship curve; wherein, the temperature-pressure relationship curve characterizes the relationship between temperature and pressure.

[0080] Step 302: Calculate the target pressure ratio based on the ratio of the condenser saturation pressure and the evaporator saturation pressure;

[0081] Step 303: Obtain the refrigeration power of the chiller, and determine the target flow coefficient based on the refrigeration power, evaporator saturation pressure, evaporator temperature and condenser temperature;

[0082] Step 304: Combine the target flow coefficient and the target pressure ratio to obtain the target coordinate point, and perform curve coordinate matching on the candidate pressure ratio characteristic curve based on the target coordinate point to obtain the target pressure ratio characteristic curve.

[0083] The advantage of this embodiment lies in that it converts the evaporator temperature and condenser temperature into evaporator saturation pressure and condenser saturation pressure, respectively, and calculates their ratio to obtain the target pressure ratio. Simultaneously, it combines the refrigeration power, evaporator saturation pressure, and temperature parameters to determine the target flow coefficient. This allows for the construction of target coordinate points to screen matching candidate pressure ratio characteristic curves, enabling subsequent energy efficiency calculations based on the guide vane opening of these candidate curves. This approach establishes the relationship between internal parameters of the refrigeration unit, such as guide vane opening, and energy efficiency, thereby improving the accuracy of refrigeration unit operation control.

[0084] In step 301 of some embodiments, the evaporator saturation pressure refers to the vapor pressure when the evaporator is in a saturated state. In some embodiments, the evaporator saturation pressure is defined as shown in the following formula:

[0085] ,

[0086] In the formula, Indicates the evaporator saturation pressure; This represents the temperature-pressure relationship curve, also known as the temperature-pressure relationship formula. This indicates the evaporator temperature, specifically the evaporator saturation temperature.

[0087] Specifically, the temperature-pressure relationship curve characterizes the relationship between saturation temperature and saturation pressure, and different refrigerants have different temperature-pressure relationship curves.

[0088] In some embodiments, the condenser saturation pressure refers to the saturation pressure of the refrigerant when it completes a phase change (from gaseous to liquid) within the condenser. The formula for calculating the condenser saturation pressure is similar to that for the evaporator saturation pressure described above, and will not be repeated here.

[0089] In step 302 of some embodiments, the target pressure ratio is the ratio of the condenser saturation pressure to the evaporator saturation pressure. In some embodiments, the target pressure ratio is defined as shown in the following formula:

[0090] ,

[0091] In the formula, Indicates the target pressure ratio; Indicates evaporator saturation pressure ; Indicates condenser saturation pressure .

[0092] In step 303 of some embodiments, the target flow coefficient is a flow coefficient calculated based on the cooling power, evaporator saturation pressure, evaporator temperature, and condenser temperature. The calculation process for the target flow coefficient is detailed in the following description of step 405, and will not be repeated here.

[0093] In step 304 of some embodiments, the target flow coefficient can be used as the abscissa and the target pressure ratio as the ordinate to obtain the target coordinate point. Curve coordinate matching means that the target coordinate point lies on the target pressure ratio characteristic curve.

[0094] Please see Figure 5 In some embodiments, step 303 may include, but is not limited to, steps 401 to 405:

[0095] Step 401: Calculate the liquid specific enthalpy based on the difference between the condenser temperature and the refrigerant subcooling of the condenser to obtain the liquid specific enthalpy at the throttle valve inlet.

[0096] Step 402: Calculate the specific enthalpy of the gas based on the evaporator saturation pressure and evaporator temperature to obtain the specific enthalpy of the gas at the guide vane inlet;

[0097] Step 403: The difference between the liquid specific enthalpy at the throttle valve inlet and the gas specific enthalpy at the guide vane inlet is determined as the specific refrigeration capacity;

[0098] Step 404: Calculate the refrigerant mass flow rate by performing a ratio calculation based on the refrigeration power and specific refrigeration capacity;

[0099] Step 405: Input the refrigerant mass flow rate, evaporator temperature and evaporator saturation pressure into the preset flow coefficient definition to calculate the flow coefficient and obtain the target flow coefficient.

[0100] The advantage of this embodiment is that it calculates the liquid specific enthalpy at the throttle valve inlet based on the difference between the condenser temperature and the refrigerant subcooling, and combines this with the evaporator saturation pressure and evaporator temperature to calculate the gas specific enthalpy at the guide vane inlet. The difference between these two values ​​is then used as the specific refrigeration capacity. This allows for precise quantification of the actual heat absorption capacity of the refrigerant in the evaporator. The refrigerant mass flow rate is calculated based on the refrigeration power and specific refrigeration capacity, and the refrigerant mass flow rate, evaporator temperature, and evaporator saturation pressure are input into a preset flow coefficient definition formula for flow coefficient calculation. This allows for accurate determination of the target flow coefficient, thereby improving the accuracy of subsequent refrigeration energy efficiency predictions and the precision of refrigeration unit operation control.

[0101] In step 401 of some embodiments, the enthalpy of the liquid at the throttle valve inlet is defined by the following formula:

[0102] ,

[0103] In the formula, Indicates the specific enthalpy of the liquid at the inlet of the throttle valve; Formula for the specific enthalpy of a saturated liquid; Indicates the condenser temperature; This indicates the refrigerant subcooling degree of the condenser.

[0104] In step 402 of some embodiments, the enthalpy of the guide vane inlet gas is defined by the following formula:

[0105] ,

[0106] In the formula, Indicates the specific enthalpy of the gas at the guide vane inlet; Formula for the specific enthalpy of superheated gas; Indicates the evaporator saturation pressure; Indicates the evaporator temperature; This indicates the superheat of the evaporator. In some embodiments, the superheat may be approximately 0.

[0107] In step 403 of some embodiments, the specific cooling capacity is the difference between the specific enthalpy of the liquid at the throttle valve inlet and the specific enthalpy of the gas at the guide vane inlet. For example, the specific cooling capacity is defined as follows: ,in, This indicates the specific cooling capacity of the evaporator. This indicates the specific enthalpy of the liquid at the inlet of the throttle valve. This indicates the specific enthalpy of the gas at the guide vane inlet. Specifically, the units for specific cooling capacity and the specific enthalpy mentioned above (specific enthalpy of the liquid at the throttle valve inlet or specific enthalpy of the gas at the guide vane inlet) can both be kilojoules per kilogram (kJ / kg).

[0108] It should be noted that in the formula, the subscript g of the parameter indicates the gaseous state (such as the superheated gaseous state of the refrigerant), the subscript s indicates the saturated state, the subscript gs indicates the saturated gaseous state, and the subscript ls indicates the saturated liquid state; in the subscripts, the symbol to the right of the comma indicates the state point (or position), where the first digit 0 indicates the stagnation state, IGVin and IGV represent the inlet and outlet of the inlet guide vane (IGV) respectively, VGDin and VGDout represent the diffuser inlet and outlet respectively, and throttlein represents the throttle valve inlet.

[0109] In step 404 of some embodiments, the refrigerant mass flow rate is the ratio of cooling power to specific cooling capacity. For example, the refrigerant mass flow rate is defined as... ,in, Indicates the refrigerant mass flow rate. This indicates the cooling power (also known as cooling capacity) of the refrigeration unit. This represents the specific cooling capacity of the refrigeration unit. In some embodiments, the specific cooling capacity of the evaporator can be approximated. Equivalent to the specific cooling capacity of a refrigeration machine , that is .

[0110] In step 405 of some embodiments, the target flow coefficient is defined as shown in the following formula:

[0111] ,

[0112] In the formula, Indicates the target flow coefficient; Indicates mass flow rate; Indicates the evaporator temperature; Indicates the evaporator saturation pressure; This represents the temperature-pressure relationship curve, also known as the temperature-pressure equation. It should be noted that in this formula, Equivalent to , Equivalent to , Equivalent to .

[0113] Please see Figure 6 In some embodiments, step 105 may include, but is not limited to, steps 501 to 506:

[0114] Step 501: Determine the evaporator saturation pressure based on the evaporator temperature and the preset refrigerant temperature-pressure relationship curve; determine the condenser saturation pressure based on the condenser temperature and the refrigerant temperature-pressure relationship curve.

[0115] Step 502: Calculate the isentropic compression temperature based on the evaporator saturation pressure and the condenser saturation pressure to obtain the isentropic compression temperature;

[0116] Step 503: Calculate the first specific enthalpy based on the isentropic compression temperature and the condenser saturation pressure to obtain the final specific enthalpy of the isentropic compression process;

[0117] Step 504: Calculate the second specific enthalpy based on the evaporator saturation pressure, evaporator temperature, and refrigerant superheat to obtain the specific enthalpy of the gas at the guide vane inlet.

[0118] Step 505: Calculate the difference between the enthalpy at the end of the isentropic compression process and the enthalpy of the gas at the guide vane inlet to obtain the isentropic compression ratio shaft work.

[0119] Step 506: Determine the specific refrigeration capacity based on the evaporator temperature, condenser temperature, refrigerant subcooling degree, and refrigerant superheat degree, and determine the ratio of the specific refrigeration capacity to the isentropic compression specific shaft work as the isentropic compression refrigeration efficiency.

[0120] The advantage of this embodiment lies in that it determines the evaporator saturation pressure and condenser saturation pressure based on the evaporator and condenser temperatures, respectively, and calculates the isentropic compression temperature and the specific enthalpy at the end of the isentropic compression process based on these. Simultaneously, it calculates the specific enthalpy of the gas at the guide vane inlet by combining the evaporator saturation pressure, evaporator temperature, and refrigerant superheat. This allows for the precise quantification of the isentropic compression specific shaft work as the enthalpy difference between the isentropic compression endpoint and the guide vane inlet, enabling the derivation of power consumption during the compression process based on thermodynamic state parameters. Furthermore, it determines the specific refrigeration capacity using the evaporator temperature, condenser temperature, refrigerant subcooling, and superheat, and uses the ratio of the specific refrigeration capacity to the isentropic compression specific shaft work as the isentropic compression refrigeration efficiency. This provides a more reliable thermodynamic basis for subsequent predictions of refrigeration efficiency, thereby improving the accuracy of refrigeration machine operation control.

[0121] In step 501 of some embodiments, the definitions of evaporator saturation pressure and condenser saturation pressure have been explained in the detailed description of step 301 above, and will not be repeated here.

[0122] In step 502 of some embodiments, the calculation process for the isentropic compression temperature can be referred to the detailed description of step 603 below, and will not be repeated here.

[0123] In step 503 of some embodiments, the enthalpy at the end of the isentropic compression process is defined by the following formula:

[0124] ,

[0125] In the formula, This represents the specific enthalpy at the end of an isentropic compression process; Formula for calculating the specific enthalpy of gaseous gases; Indicates the condenser saturation pressure; This indicates the isentropic compression temperature.

[0126] In step 504 of some embodiments, the definition of the specific enthalpy of the guide vane inlet gas has been explained in the detailed description of step 402 above, and will not be repeated here.

[0127] In step 505 of some embodiments, the isentropic compression ratio shaft work includes the isentropic compression ratio shaft work per unit mass of refrigerant from the outlet of the inlet guide vane (IGV) to the inlet of the diffuser (VGD), and the single-stage isentropic compression ratio shaft work per unit mass of refrigerant.

[0128] In some embodiments, the isentropic compression ratio shaft work per unit mass of refrigerant from the outlet of the inlet guide vane (IGV) to the inlet of the diffuser (VGD) is defined by the following formula:

[0129] ,

[0130] In the formula, The isentropic compression ratio shaft work expressed as the work done per unit mass of refrigerant from the outlet of the inlet guide vane (IGV) to the inlet of the diffuser (VGD). ; Indicates the diffuser inlet specific enthalpy; This indicates the specific enthalpy of the gas entering the guide vane.

[0131] It should be noted that VGD refers to Variable Geometry Diffuser, which is a diffuser that can adjust the geometry of the diffuser channel.

[0132] In some embodiments, the shaft work per unit mass of refrigerant for single-stage isentropic compression ratio is defined by the following formula:

[0133] ,

[0134] In the formula, Shaft work per unit mass of refrigerant in a single-stage isentropic compression ratio. This represents the specific enthalpy at the end of an isentropic compression process; This indicates the specific enthalpy of the gas entering the guide vane.

[0135] In step 506 of some embodiments, the isentropic compression refrigeration efficiency is the ratio of specific refrigeration capacity to isentropic compression specific shaft work. The definition and calculation process of specific refrigeration capacity have been explained in the detailed descriptions of steps 401 to 403 above, and will not be repeated here. In some embodiments, the isentropic compression refrigeration efficiency is defined by the following formula:

[0136] ,

[0137] In the formula, Indicates isentropic compression refrigeration efficiency; Indicates specific cooling capacity; The isentropic compression ratio shaft work represents the isentropic compression process, specifically the isentropic compression ratio shaft work from the inlet of the guide vane to the outlet of the guide vane. That is, the single-stage isentropic compression ratio shaft work mentioned above .

[0138] Please see Figure 7 In some embodiments, step 502 may include, but is not limited to, steps 601 to 603:

[0139] Step 601: Based on the evaporator saturation pressure, search for the fitting coefficient in the preset fitting coefficient table to obtain the first fitting coefficient, and construct the first specific entropy relationship based on the first fitting coefficient and the preset specific entropy relationship template; wherein, the specific entropy relationship template characterizes the relationship between temperature and specific entropy at a specified pressure, the specific entropy relationship template contains unknown fitting coefficients and temperature values, and the fitting coefficients in the fitting coefficient table are used to indicate the relationship between pressure and fitting coefficients;

[0140] Step 602: Find the fitting coefficient in the fitting coefficient table based on the condenser saturation pressure to obtain the second fitting coefficient, and construct the second specific entropy relationship based on the second fitting coefficient and the specific entropy relationship template;

[0141] Step 603: Adjust the temperature value so that the values ​​of the first specific entropy relationship and the second specific entropy relationship are equal, and obtain the isentropic compression temperature.

[0142] The advantage of this embodiment lies in that, based on the evaporator saturation pressure and the condenser saturation pressure, the corresponding first and second fitting coefficients are found in a preset fitting coefficient table, respectively. These coefficients, combined with a specific entropy relationship template, are then used to construct the first and second specific entropy relationships. This dynamically transforms pressure parameters into thermodynamic expressions describing the relationship between temperature and specific entropy. By adjusting the temperature value to make the two specific entropy relationships equal, the isentropic compression temperature can be solved. This allows for accurate calculation of the isentropic compression temperature, providing a reliable thermodynamic benchmark for the subsequent derivation of the isentropic compression specific shaft work and isentropic compression refrigeration efficiency, thereby improving the accuracy of refrigeration unit operation control.

[0143] In step 601 of some embodiments, the specific entropy relation template is defined as follows: .in, Indicates pressure, Indicates temperature. Represents the specific entropy of the gaseous state. With pressure and temperature The relationship between them , , and All of these represent fitting coefficients related to pressure.

[0144] In some embodiments, the fitting coefficient , , and All of these can be found in the fitting coefficient table. In another embodiment, the pressure fitting coefficients mentioned above can also be calculated by weighted summation based on the coefficients in the fitting coefficient table; this is not a limitation here.

[0145] In some embodiments, the first fitting coefficient is obtained by looking up the fitting coefficient table based on the evaporator saturation pressure. In some embodiments, the first fitting coefficient can be filled into the specific entropy relation template to construct the first specific entropy relation. For example, the definition of the first specific entropy relation is shown in the following formula:

[0146] ,

[0147] In the formula, This represents the first specific entropy relationship; Indicates the evaporator saturation pressure; Indicates the guide vane inlet temperature; , , and All represent the first fitting coefficients.

[0148] In step 602 of some embodiments, the second fitting coefficient is obtained by looking up the fitting coefficient table based on the condenser saturation pressure. In some embodiments, the second fitting coefficient can be filled into a specific entropy relationship template to construct a second specific entropy relationship. For example, the definition of the second specific entropy relationship is shown in the following formula:

[0149] ,

[0150] In the formula, This represents the second specific entropy relationship; Indicates the condenser saturation pressure; Indicates the isentropic compression temperature; , , and Both represent the second fitting coefficients.

[0151] In step 603 of some embodiments, the isentropic compression temperature can be calculated based on the following formula:

[0152] ,

[0153] In the formula, This represents the first specific entropy relationship; This represents the second specific entropy relationship.

[0154] Please see Figure 8 In some embodiments, system operating efficiency includes motor efficiency, inverter efficiency, and bearing transmission efficiency;

[0155] The process of obtaining the system operating efficiency of the refrigeration system in step 106 may include, but is not limited to, steps 701 to 703:

[0156] Step 701: Obtain the motor efficiency of the chiller;

[0157] Step 702: Obtain the inverter speed of the chiller, and calculate the inverter efficiency based on the inverter speed to obtain the inverter efficiency;

[0158] Step 703: Input the evaporator temperature into the preset temperature bearing transmission relationship to calculate the bearing transmission efficiency and obtain the bearing transmission efficiency; wherein, the temperature bearing transmission relationship represents the relationship between the refrigerant temperature of the evaporator and the bearing transmission efficiency.

[0159] The advantage of this embodiment lies in its ability to accurately capture the energy loss characteristics of the inverter under different operating speeds by obtaining the motor efficiency of the refrigeration unit and dynamically calculating the inverter efficiency based on the inverter speed. This avoids using fixed efficiency values ​​or ignoring the impact of inverter operating condition fluctuations. By inputting the evaporator temperature into a preset temperature-bearing transmission relationship formula to calculate the bearing transmission efficiency, the influence of refrigerant temperature on bearing friction characteristics can be correlated, thus more realistically reflecting the energy loss in the bearing transmission process. By comprehensively quantifying the dynamic efficiency of the three core energy-consuming components in the refrigeration system—motor, inverter, and bearings—the accuracy of system operating efficiency calculations can be improved, providing more reliable input parameters for subsequent prediction of refrigeration energy efficiency, thereby enhancing the accuracy of refrigeration unit operation control.

[0160] In step 701 of some embodiments, the motor efficiency of the refrigerator can be obtained based on the motor efficiency characteristic curve of the refrigerator. In another embodiment, the motor efficiency can also be obtained in other ways, such as based on experience, and is not limited thereto.

[0161] In step 702 of some embodiments, the inverter efficiency is defined as... ,in, Indicates the inverter efficiency. Indicates the speed of the frequency converter. This indicates the relationship between inverter efficiency and speed.

[0162] In step 703 of some embodiments, the bearing transmission efficiency is defined as... ,in, Indicates the bearing transmission efficiency; This indicates the evaporator temperature, specifically the evaporator saturation temperature. This expresses the relationship between bearing transmission efficiency and temperature, also known as the temperature-bearing transmission relationship formula.

[0163] Please see Figure 9 and Figure 10 In some embodiments, the refrigeration unit may specifically be a single-stage centrifugal compression refrigeration unit. Taking a single-stage centrifugal compression refrigeration unit as an example, Figure 9This is the temperature-entropy diagram of a single-stage centrifugal compression refrigeration cycle for this refrigerator. The refrigerant used in the refrigerator is R134a (tetrafluoroethane). Figure 9 The diagram illustrates four processes: condenser cooling, expansion valve throttling, evaporator refrigeration, and compressor compression. Compressor compression includes three processes: inlet guide vane IGV regulation, impeller compression, and diffuser regulation. It should be noted that because the saturation temperature of R134a changes with the specific entropy of the saturated gas at a relatively steep slope, the compressor compression process also occurs within a relatively small range of specific entropy changes. Figure 10 yes Figure 9 A magnified view of a portion of the image is provided to more clearly illustrate the centrifugal compression process. Figure 10 Used to characterize the changes in the state of compression and stagnation.

[0164] It should be noted that, in Figure 9 and Figure 10 In this diagram, the symbol 0 represents the stagnation state; IGVin and IGVout represent the inlet and outlet of the inlet guide vane (IGV), respectively; VGDin and VGDout represent the inlet and outlet of the diffuser (VGD), respectively. 0IGVins represents the state point at the IGV inlet stagnation state where isentropic compression reaches the condenser pressure; 0IGVouts and 0IGVoutss represent the state points at the IGV outlet stagnation state where isentropic compression reaches the condenser pressure and the VGD inlet stagnation pressure, respectively; pIGVin and p0IGVin represent the IGV inlet pressure and inlet stagnation pressure, respectively, where the IGV inlet stagnation pressure is approximately equal to the evaporator saturation pressure pevap; pIGVout and p0IGVout represent the IGV outlet pressure and outlet stagnation pressure, respectively; pVGDin and p0VGDin represent the VGD inlet pressure and inlet stagnation pressure, respectively; pVGDout and p0VGDout represent the VGD outlet pressure and outlet stagnation pressure, respectively, where the VGD outlet stagnation pressure is approximately equal to the condenser saturation pressure pcond. It should be noted that the light blue curve is used to represent the relationship between the compressor temperature T and the specific entropy s, and the straight lines (including dashed lines and solid lines) and their arrows are used to indicate the state change process of the refrigeration machine during the compression process. Different colors of the straight lines are used to distinguish the state change process, but this application embodiment does not limit this.

[0165] In some embodiments, the throttling process of the inlet guide vane (IGV) and diffuser (VGD) can be considered an adiabatic process; therefore, the inlet and outlet specific enthalpies of these two components are equal, or in other words, the inlet and outlet stagnation temperatures of these two components are the same. Figure 10As shown, for example, if there is no IGV and VGD (or both IGV and VGD are 100% open), the isentropic compression process of the compressor impeller is from 0IGVin to 0IGVins. As another example, when IGV is on, if there is no VGD (or VGD is 100% open), the isentropic compression process of the compressor impeller is from 0IGVout to 0IGVouts. When both IGV and VGD are on, the isentropic compression process of the compressor impeller is from 0IGVout to 0IGVoutss.

[0166] This application also provides a controller, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the above-described chiller operation control method. The controller may include any intelligent terminal such as a PLC (Programmable Logic Controller).

[0167] Please see Figure 11 , Figure 11 The hardware structure of a controller according to another embodiment is illustrated. The controller includes:

[0168] The processor 901 can be implemented using a general-purpose CPU (Central Processing Unit), microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this application.

[0169] The memory 902 can be implemented as a read-only memory (ROM), static storage device, dynamic storage device, or random access memory (RAM). The memory 902 can store the operating system and other application programs. When the technical solutions provided in the embodiments of this specification are implemented through software or firmware, the relevant program code is stored in the memory 902 and is called and executed by the processor 901 using the refrigerator operation control method of the embodiments of this application.

[0170] The input / output interface 903 is used to implement information input and output;

[0171] The communication interface 904 is used to enable communication and interaction between this device and other devices. Communication can be achieved through wired means (such as USB, Ethernet cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.).

[0172] Bus 905 transmits information between various components of the device (e.g., processor 901, memory 902, input / output interface 903, and communication interface 904);

[0173] The processor 901, memory 902, input / output interface 903, and communication interface 904 are connected to each other within the device via bus 905.

[0174] This application embodiment also provides a refrigeration system, which includes: the controller, the refrigeration unit, and the cold storage device described above; the controller is communicatively connected to the refrigeration unit, and the cold storage device is physically connected to the refrigeration unit.

[0175] The specific implementation method of this refrigeration system is basically the same as the specific implementation method of the above-mentioned refrigeration machine operation control method, and will not be described again here.

[0176] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described refrigerator operation control method.

[0177] Memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, memory may optionally include memory remotely located relative to the processor, and these remote memories can be connected to the processor via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0178] It should be noted that the software tools or components not belonging to our company that appear in the embodiments of this application are merely examples and do not represent actual use.

[0179] The embodiments described in this application are intended to more clearly illustrate the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided by the embodiments of this application. Those skilled in the art will know that with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems.

[0180] Those skilled in the art will understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of this application, and may include more or fewer steps than shown, or combine certain steps, or different steps.

[0181] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0182] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0183] It should be understood that in this application, "at least one (item)" means one or more, and "more than one" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist.

[0184] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes multiple instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing programs, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0185] The preferred embodiments of the present application have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present application. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and substance of the embodiments of the present application shall be within the scope of the claims of the present application.

Claims

1. A method for controlling the operation of a refrigeration unit, characterized in that, The method includes: Acquire candidate pressure ratio characteristic curves and candidate isentropic compression efficiency curves of the refrigeration unit in the refrigeration system; wherein, the candidate pressure ratio characteristic curve is used to indicate the correlation between the ratio of the evaporator pressure to the condenser pressure of the refrigeration unit and the performance index of the compressor, and the candidate isentropic compression efficiency curve is used to indicate the correlation between the isentropic compression efficiency of the compressor and the performance index of the compressor, wherein the performance index includes guide vane opening degree and compressor speed; Obtain the evaporator temperature of the evaporator and the condenser temperature of the condenser; Based on the evaporator temperature, the condenser temperature, and the candidate rotation speed, the candidate pressure ratio characteristic curves are screened to obtain the target pressure ratio characteristic curve. The combination of the guide vane opening of the target pressure ratio characteristic curve and the candidate rotation speed is determined as the candidate performance index combination. The isentropic compression efficiency is calculated based on the evaporator temperature, the condenser temperature, and the candidate isentropic compression efficiency curve corresponding to the candidate performance index combination, to obtain the target isentropic compression efficiency corresponding to the candidate performance index combination. The isentropic compression refrigeration efficiency is determined based on the evaporator temperature, the condenser temperature, the refrigerant subcooling of the condenser, and the refrigerant superheat of the evaporator. The system operating efficiency of the refrigeration system is obtained, and the predicted refrigeration efficiency corresponding to the candidate performance index combination is obtained by weighted summation based on the system operating efficiency, the isentropic compression refrigeration efficiency and the target isentropic compression efficiency. The equipment parameters of the refrigeration unit are adjusted based on the candidate performance index combination corresponding to the largest predicted refrigeration energy efficiency.

2. The method according to claim 1, characterized in that, The coordinates of the candidate pressure ratio characteristic curve include the flow coefficient and the pressure ratio, where the pressure ratio is the ratio of the pressure of the evaporator to the pressure of the condenser. The step of filtering candidate pressure ratio characteristic curves based on the evaporator temperature, the condenser temperature, and candidate rotational speed to obtain the target pressure ratio characteristic curve includes: The evaporator saturation pressure is determined based on the evaporator temperature and the preset temperature-pressure relationship curve, and the condenser saturation pressure is determined based on the condenser temperature and the temperature-pressure relationship curve; wherein, the temperature-pressure relationship curve characterizes the relationship between temperature and pressure. The target pressure ratio is obtained by calculating the ratio of the condenser saturation pressure and the evaporator saturation pressure. The refrigeration power of the refrigerator is obtained, and the target flow coefficient is determined based on the refrigeration power, the evaporator saturation pressure, the evaporator temperature, and the condenser temperature. The target coordinate point is obtained by combining the target flow coefficient and the target pressure ratio. The target coordinate point is then used to match the candidate pressure ratio characteristic curve to obtain the target pressure ratio characteristic curve.

3. The method according to claim 2, characterized in that, The determination of the target flow coefficient based on the refrigeration power, the evaporator saturation pressure, the evaporator temperature, and the condenser temperature includes: The liquid specific enthalpy is calculated based on the difference between the condenser temperature and the refrigerant subcooling of the condenser to obtain the liquid specific enthalpy at the throttle valve inlet. The specific enthalpy of the gas at the guide vane inlet is calculated based on the saturation pressure and temperature of the evaporator. The difference between the specific enthalpy of the liquid at the throttle valve inlet and the specific enthalpy of the gas at the guide vane inlet is determined as the specific cooling capacity; The refrigerant mass flow rate is obtained by calculating the ratio between the cooling power and the specific cooling capacity. The refrigerant mass flow rate, the evaporator temperature, and the evaporator saturation pressure are input into a preset flow coefficient definition to calculate the flow coefficient, thereby obtaining the target flow coefficient.

4. The method according to any one of claims 1 to 3, characterized in that, The determination of isentropic compression refrigeration efficiency based on the evaporator temperature, the condenser temperature, the refrigerant subcooling of the condenser, and the refrigerant superheat of the evaporator includes: The evaporator saturation pressure is determined based on the evaporator temperature and the preset refrigerant temperature-pressure relationship curve, and the condenser saturation pressure is determined based on the condenser temperature and the refrigerant temperature-pressure relationship curve. The isentropic compression temperature is calculated based on the evaporator saturation pressure and the condenser saturation pressure to obtain the isentropic compression temperature. The first specific enthalpy is calculated based on the isentropic compression temperature and the condenser saturation pressure to obtain the final specific enthalpy of the isentropic compression process. The specific enthalpy of the gas at the guide vane inlet is obtained by calculating the second specific enthalpy based on the evaporator saturation pressure, the evaporator temperature, and the refrigerant superheat. The isentropic compression ratio shaft work is obtained by calculating the difference between the specific enthalpy at the end of the isentropic compression process and the specific enthalpy of the gas at the guide vane inlet. The specific refrigeration capacity is determined based on the evaporator temperature, the condenser temperature, the refrigerant subcooling degree, and the refrigerant superheat degree, and the ratio of the specific refrigeration capacity to the isentropic compression specific shaft work is determined as the isentropic compression refrigeration energy efficiency.

5. The method according to claim 4, characterized in that, The step of calculating the isentropic compression temperature based on the evaporator saturation pressure and the condenser saturation pressure to obtain the isentropic compression temperature includes: The fitting coefficient is searched in a preset fitting coefficient table based on the evaporator saturation pressure to obtain the first fitting coefficient, and a first specific entropy relationship is constructed based on the first fitting coefficient and a preset specific entropy relationship template; wherein, the specific entropy relationship template characterizes the relationship between temperature and specific entropy at a specified pressure, the specific entropy relationship template contains unknown fitting coefficients and temperature values, and the fitting coefficients in the fitting coefficient table are used to indicate the relationship between pressure and fitting coefficients. The fitting coefficients are searched in the fitting coefficient table based on the saturation pressure of the condenser to obtain the second fitting coefficients, and the second specific entropy relationship is constructed based on the second fitting coefficients and the specific entropy relationship template. The temperature value is adjusted so that the values ​​of the first specific entropy relationship and the second specific entropy relationship are equal, thereby obtaining the isentropic compression temperature.

6. The method according to any one of claims 1 to 3, characterized in that, The acquisition of candidate pressure ratio characteristic curves and candidate isentropic compression efficiency curves of the refrigerator in the refrigeration system includes: Obtain the initial pressure ratio characteristic curve and the initial isentropic compression efficiency curve of the refrigerator in the refrigeration system; wherein, the first coordinate of the initial pressure ratio characteristic curve is the first refrigeration temperature, and the first coordinate of the initial isentropic compression efficiency curve is the second refrigeration temperature; Obtain the impeller diameter parameters and refrigerant type parameters of the refrigeration machine; The impeller diameter parameter, the refrigerant type parameter, and the first refrigeration temperature are input into a preset temperature-flow coefficient conversion function to calculate the flow coefficient, thereby obtaining the first flow coefficient; wherein, the temperature-flow coefficient conversion function is used to characterize the correlation between temperature and flow coefficient; The impeller diameter parameter, the refrigerant type parameter, and the second refrigeration temperature are input into the temperature-flow coefficient conversion function to calculate the flow coefficient, thereby obtaining the second flow coefficient. The first coordinate of the initial pressure ratio characteristic curve is updated according to the first flow coefficient to obtain the candidate pressure ratio characteristic curve, and the first coordinate of the initial isentropic compression efficiency curve is updated according to the second flow coefficient to obtain the candidate isentropic compression efficiency curve.

7. The method according to any one of claims 1 to 3, characterized in that, The system operating efficiency includes motor efficiency, frequency converter efficiency, and bearing transmission efficiency; The process of obtaining the system operating efficiency of the refrigeration system includes: Obtain the motor efficiency of the refrigerator; The inverter speed of the chiller is obtained, and the inverter efficiency is calculated based on the inverter speed to obtain the inverter efficiency. The bearing transmission efficiency is calculated by inputting the evaporator temperature into a preset temperature bearing transmission formula; wherein, the temperature bearing transmission formula characterizes the relationship between the refrigerant temperature of the evaporator and the bearing transmission efficiency.

8. A controller, characterized in that, The controller includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the refrigerator operation control method according to any one of claims 1 to 7.

9. A refrigeration system, characterized in that, The refrigeration system includes: The controller, refrigerator, and cold storage device as described in claim 8; the controller is communicatively connected to the refrigerator, and the cold storage device is physically connected to the refrigerator.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the refrigerator operation control method according to any one of claims 1 to 7.

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