Refrigerating machine screening method and device, electronic equipment and storage medium

Abstract

The embodiment of the invention provides a refrigerator screening method and device, electronic equipment and a storage medium, and belongs to the technical field of refrigeration. The method comprises the steps that for any type of refrigerating machine in various types of refrigerating machines, actual energy efficiency and ideal energy efficiency of the refrigerating machine under various preset conditions are obtained; calculating according to the actual energy efficiency and the ideal energy efficiency of the refrigerator under each preset condition to obtain the relative energy efficiency and the isentropic compression efficiency of the refrigerator under each preset condition; according to the relative energy efficiency and the isentropic compression efficiency of the refrigerator under each preset condition, a first change curve of the relative energy efficiency of the refrigerator and a second change curve of the isentropic compression efficiency of the refrigerator are obtained; and according to the first change curve of the relative energy efficiency of each type of refrigerator and the second change curve of the isentropic compression efficiency, target refrigerators are determined, and the target refrigerators comprise at least one type of refrigerator selected from the various types of refrigerators. The embodiment of the invention can provide a basis for refrigerator model selection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of refrigeration, and in particular to a refrigerant machine screening method and device, an electronic device, and a storage medium. BACKGROUND

[0002] As an important equipment in the fields of large air conditioning systems and industrial refrigeration, the energy efficiency of a centrifugal refrigerant machine directly affects the operation cost and energy consumption of a system. At present, the main indicator for evaluating the energy efficiency of a refrigerant machine is the coefficient of performance (COP), which is defined as the refrigeration capacity obtained per unit input electric power. The COP value is affected by multiple factors, including cooling water temperature, chilled water temperature, small temperature difference of an evaporator and a condenser, compressor efficiency, frequency converter efficiency, motor efficiency, mechanical transmission efficiency, and the like.

[0003] In actual applications, when evaluating the operation efficiency of a refrigerant machine body, the influence of external environmental parameters of a refrigerant system needs to be stripped off to realize horizontal comparison of the performance of different working conditions or different models of refrigerant machines. However, the coefficient of performance COP is affected by the thermodynamic cycle efficiency of a refrigerant, and it is difficult to directly compare the performance of different working conditions or different models of refrigerant machines. The commonly used single-stage isentropic compression efficiency and multi-variable compression efficiency in the prior art are difficult to apply to the evaluation of the compressor efficiency of multi-stage compression and multi-stage throttling cooling. Therefore, when a refrigerant machine is designed and selected, it is easy to cause mismatching with actual requirements. SUMMARY

[0004] The main purpose of the embodiments of the present application is to propose a refrigerant machine screening method, device, electronic device, and storage medium, which can solve the problem that it is difficult to match actual requirements in the refrigerant machine screening process in the prior art.

[0005] To achieve the above-mentioned purpose, a first aspect of the embodiments of the present application proposes a refrigerant machine screening method, which comprises the following steps: For any model of refrigerant machine in multiple models of refrigerant machines, actual energy efficiency and ideal energy efficiency of the refrigerant machine under multiple preset conditions are obtained, wherein the cooling water temperature and / or load rate included in different preset conditions are different; According to the actual energy efficiency and ideal energy efficiency of the refrigerant machine under each preset condition, relative energy efficiency and isentropic compression efficiency of the refrigerant machine under each preset condition are obtained; According to the relative energy efficiency and isentropic compression efficiency of the refrigerant machine under each preset condition, a first change curve of the relative energy efficiency and a second change curve of the isentropic compression efficiency of the refrigerant machine are obtained; A target refrigerator is determined according to a first change curve of the relative energy efficiency of each model of the refrigerator and a second change curve of the isentropic compression efficiency. The target refrigerator includes at least one model of refrigerator selected from the multiple models of refrigerators.

[0006] In some embodiments, obtaining, for any refrigerator of multiple models, the actual energy efficiency and the ideal energy efficiency of the refrigerator under multiple preset conditions includes: For any of the various models of refrigerators, perform the following: For each of the preset conditions, perform the following processing: Obtaining an energy efficiency matrix of the refrigerator under the preset conditions, where the energy efficiency matrix represents a relationship between the actual energy efficiency of the refrigerator under the preset conditions and the cooling water temperature under the preset conditions, and a relationship between the actual energy efficiency of the refrigerator under the preset conditions and the load rate under the preset conditions; Calculating the saturation temperature of the condenser and the saturation temperature of the evaporator in the refrigerator based on the energy efficiency matrix, heat transfer equation of the heat exchanger, and cooling water operation mode of the refrigerator under the preset conditions, wherein the cooling water operation mode is obtained by the energy efficiency matrix of the refrigerator; The ideal energy efficiency of the refrigerator under the preset conditions is calculated according to the saturation temperature of the condenser in the refrigerator and the saturation temperature of the evaporator in the refrigerator.

[0007] In some embodiments, calculating the ideal energy efficiency of the refrigerator under the preset conditions based on the saturation temperature of the condenser and the saturation temperature of the evaporator includes: Determining the specific cooling capacity and the isentropic compression specific work during infinite-stage isentropic compression and infinite-stage throttling cooling according to the saturation temperature of the condenser in the refrigerator, the saturation temperature of the evaporator in the refrigerator, and the thermodynamic parameters of the refrigerant in the refrigerator; The ratio of the specific cooling capacity to the isentropic compression specific work is used as the ideal energy efficiency of the refrigerator under the preset conditions.

[0008] In some embodiments, the calculating according to the actual energy efficiency and the ideal energy efficiency of the refrigerator under each of the preset conditions to obtain the relative energy efficiency and the isentropic compression efficiency of the refrigerator under each of the preset conditions includes: For each of the preset conditions, perform the following processing: The ratio of the actual energy efficiency of the refrigerator under the preset conditions to the ideal energy efficiency is used as the relative energy efficiency of the refrigerator under the preset conditions; The product of the refrigeration coefficient, compression work coefficient, inverter efficiency, AC motor efficiency, and bearing efficiency of the refrigerator is used as a first coefficient, wherein the refrigeration coefficient and the compression work coefficient are obtained based on the total number of compression stages of the compressor in the refrigerator, the saturation temperature of the evaporator, and the saturation temperature of the condenser; The ratio of the relative energy efficiency to the first coefficient is used as the isentropic compression efficiency.

[0009] In some embodiments, the first variation curve represents a curve showing a change in relative energy efficiency with a load rate at a preset cooling water temperature, and the second variation curve represents a curve showing a change in isentropic compression efficiency with a load rate at a preset cooling water temperature; Determining a target refrigerator according to the first change curve of the relative energy efficiency of each refrigerator model and the second change curve of the isentropic compression efficiency includes: For any one of the multiple models of refrigerators, determining a target operating range of the refrigerator according to a first variation curve of the relative energy efficiency of the refrigerator under each of the preset conditions; The target refrigerator is determined according to the target operating range of each model of refrigerator and the second variation curve of the isentropic compression efficiency.

[0010] In some embodiments, the target operating range of the refrigerator represents the cooling water temperature of the refrigerator under each of the preset conditions when the relative efficiency of the refrigerator is greater than a target threshold, and the target load rate range corresponding to each cooling water temperature; For any one of the multiple models of refrigerators, determining a target operating range of the refrigerator according to a first variation curve of the relative energy efficiency of the refrigerator under each of the preset conditions includes: For any of the multiple models of refrigerators, perform the following processing: For each of the preset conditions, perform the following processing: According to the cooling water temperature under the preset conditions, obtaining a maximum value of the relative energy efficiency in the first variation curve under the preset conditions; Multiplying the maximum value of the relative energy efficiency by a preset coefficient to obtain the target threshold under the preset conditions; The load rate interval corresponding to the relative energy efficiency greater than the target threshold is used as the target load rate interval corresponding to the cooling water temperature under the preset conditions; The cooling water temperature under each of the preset conditions and the target load rate range corresponding to each of the cooling water temperatures are used as the target operating range of the refrigerator.

[0011] In some embodiments, determining the target refrigerator according to the target operating range of each refrigerator model and the second variation curve of the isentropic compression efficiency includes: Obtain the cooling water temperature range and load rate range for the chiller application scenario; According to the cooling water temperature range and the load rate range, a refrigerator of multiple models whose target operating interval is within the cooling water temperature range and the load rate range and whose isentropic compression efficiency corresponding to the second change curve within the cooling water temperature range and the load rate range is the highest is selected as the target refrigerator.

[0012] To achieve the above-mentioned purpose, a second aspect of an embodiment of the present application provides a refrigerator screening device, the device comprising: an acquisition module, configured to acquire, for any one of a plurality of models of refrigerators, actual energy efficiency and ideal energy efficiency of the refrigerator under a plurality of preset conditions, wherein different preset conditions include different cooling water temperatures and / or load rates; A first calculation module is configured to calculate, based on the actual energy efficiency and ideal energy efficiency of the refrigerator under each of the preset conditions, the relative energy efficiency and isentropic compression efficiency of the refrigerator under each of the preset conditions; a second calculation module, configured to obtain a first change curve of the relative energy efficiency and a second change curve of the isentropic compression efficiency of the refrigerator according to the relative energy efficiency and the isentropic compression efficiency of the refrigerator under each of the preset conditions; A screening module is used to determine a target refrigerator based on a first change curve of the relative energy efficiency of each model of the refrigerator and a second change curve of the isentropic compression efficiency, wherein the target refrigerator includes at least one model of refrigerator selected from the multiple models of refrigerators.

[0013] To achieve the above-mentioned purpose, the third aspect of an embodiment of the present application proposes an electronic device, which includes a memory and a processor, wherein the memory stores a computer program, and the processor implements the method described in the first aspect when executing the computer program.

[0014] To achieve the above-mentioned purpose, the fourth aspect of the embodiments of the present application proposes a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the method described in the first aspect.

[0015] The refrigerator screening method, device, electronic device and storage medium proposed in the present application obtain the actual energy efficiency and ideal energy efficiency of multiple models of refrigerators under different cooling water temperature and load rate conditions. The actual energy efficiency and ideal energy efficiency are obtained to remove the influence of external environmental parameters on the performance of the refrigerator; the relative energy efficiency and isentropic compression efficiency under each condition are calculated based on the actual energy efficiency and ideal energy efficiency. The relative energy efficiency reflects the actual efficiency level of the refrigerator relative to the ideal situation, and the isentropic compression efficiency quantifies the gas dynamics performance of the compressor; based on the relative energy efficiency and isentropic compression efficiency, a first change curve of the relative energy efficiency and a second change curve of the isentropic compression efficiency are obtained. The first change curve and the second change curve respectively show the trends of the relative energy efficiency and the isentropic compression efficiency with the working conditions, and comprehensively reflect the performance characteristics of the refrigerator under different conditions; finally, the target refrigerator is determined based on the first change curve and the second change curve of each model of refrigerator. This application obtains the actual energy efficiency and ideal energy efficiency of the refrigerator under different preset conditions, calculates the relative energy efficiency and isentropic compression efficiency, generates a change curve and determines the target refrigerator. It can effectively separate the influence of external environmental parameters and energy conversion efficiency loss, provide normalized indicators, and facilitate the performance comparison of refrigerators of different models. At the same time, the isentropic compression efficiency analysis provides a theoretical basis for selection and accurately defines the high-efficiency operation range. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 1 is a flow chart of a refrigerator screening method provided in an embodiment of the present application; Figure 2 Schematic diagram of the relative energy efficiency changes of a typical base load variable frequency centrifugal refrigerator under different operating conditions provided by an embodiment of the present application; Figure 3 Schematic diagram of the maximum relative energy efficiency and corresponding refrigeration load rate of the base load variable frequency centrifugal refrigerator provided in an embodiment of the present application; Figure 4 This is a schematic diagram of the high-efficiency operating area of ​​refrigeration machine A provided in an embodiment of the present application; Figure 5 This is a schematic diagram of the high-efficiency operating area of ​​refrigeration machine B provided in an embodiment of the present application; Figure 6 This is a schematic diagram of the high-efficiency operating area of ​​refrigeration machine C provided in an embodiment of the present application; Figure 7 Schematic diagram of the isentropic compression efficiency of the compressor of refrigerator A provided in an embodiment of the present application; Figure 8 Schematic diagram of the isentropic compression efficiency of the compressor of refrigerator B provided in an embodiment of the present application; Figure 9 Schematic diagram of the isentropic compression efficiency of the refrigerator C compressor provided in an embodiment of the present application; Figure 10Schematic diagram of the relative energy efficiency (ice-making condition) of the dual-mode fixed-frequency centrifugal refrigerator provided in an embodiment of the present application; Figure 11 Schematic diagram of the relative energy efficiency (air conditioning working condition) of the dual-operating-mode fixed-frequency centrifugal refrigerator provided in an embodiment of the present application; Figure 12 Schematic diagram of the isentropic compression efficiency (ice-making condition) of a dual-mode fixed-frequency single-stage compression centrifugal refrigerator provided in an embodiment of the present application; Figure 13 This is a schematic diagram of the isentropic compression efficiency (air-conditioning working condition) of a dual-mode fixed-frequency single-stage compression centrifugal refrigerator provided in an embodiment of the present application; Figure 14 Schematic diagram of the isentropic compression efficiency (ice-making condition) of a dual-condition, fixed-frequency, two-stage compression centrifugal refrigerator provided in an embodiment of the present application; Figure 15 Schematic diagram of the isentropic compression efficiency (air-conditioning working condition) of a dual-mode fixed-frequency two-stage compression centrifugal refrigerator provided in an embodiment of the present application; Figure 16 Schematic diagram of the structure of the refrigerator screening device provided in an embodiment of the present application; Figure 17 This is a schematic diagram of the hardware structure of the electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0018] It should be noted that although the device schematics illustrate functional module divisions and the flowcharts illustrate logical sequences, in certain circumstances, the steps shown or described may be performed in a sequence that differs from the module divisions in the device or the sequence in the flowcharts. The terms "first," "second," and so on, in the specification, claims, and drawings, are used to distinguish similar items and are not necessarily used to describe a specific sequence or precedence.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein are for the purpose of describing the embodiments of this application only and are not intended to limit this application.

[0020] A chiller's coefficient of performance (COP) is an energy efficiency metric that assesses the cooling capacity it outputs per unit of electrical work input. It depends on the system's cooling and chilled water temperatures, the temperature differential between the chiller's evaporator and condenser, compressor efficiency, and the efficiency of the inverter, motor, and mechanical transmission. Cooling and chilled water temperatures, as well as the temperature differential between the evaporator and condenser, affect the energy efficiency of the chiller's refrigerant thermodynamic cycle and can be considered the influence of the refrigerant system's external environmental parameters. Inverter efficiency, motor efficiency, and mechanical transmission efficiency affect power losses from electrical input to the compressor shaft, representing losses in the useful work input process. Compressor efficiency, on the other hand, is an evaluation parameter of the compressor's aerodynamic performance and reflects the operating efficiency and performance of the chiller itself. The isentropic compression efficiency is commonly used to represent compressor efficiency, which is the ratio of isentropic compression work to actual compressor work. For the same chiller, when evaluating the differences in chiller operating efficiency at different cooling and chilled water temperatures, it is necessary to decouple and isolate the impact of the refrigerant system's external environmental parameters on chiller performance.

[0021] In practical applications, there are many technical difficulties in evaluating the performance of refrigerators: when using the coefficient of performance (COP) to directly analyze performance, it is not possible to directly judge the energy efficiency of the refrigerator itself through the COP value because it is significantly affected by the thermodynamic cycle efficiency determined by the temperature of the chilled water and the cooling water; the coefficient of performance (COP) is an absolute energy efficiency value and has not been normalized, resulting in difficulty in directly comparing the operating performance of the same refrigerator under different operating conditions or the performance of different refrigerators; the lack of a normalized relative energy efficiency index makes it difficult to determine the efficient operating area of ​​different refrigerators under different operating conditions, which brings difficulties to the selection and operation optimization of the refrigerator; in the existing technology, Commonly used definitions such as single-stage isentropic compression efficiency and variable compression efficiency have limitations when evaluating the efficiency of compressors with multi-stage compression and multi-stage throttling cooling. They cannot accurately reflect the impact of factors such as the number of compressor stages, cooling water temperature, refrigeration temperature, and load rate on efficiency, and are difficult to apply to the performance analysis of compressors with different compression forms such as single-stage, two-stage, and three-stage. In the design and selection stage of refrigerators, there is a lack of clear theoretical basis for the selection of compression stages (such as single-stage compression and two-stage compression) and the performance comparison between baseload refrigerators and dual-mode refrigerators. When analyzing refrigerator design and operating performance data, there is a lack of effective tools to accurately evaluate the core performance of the compressor.

[0022] Based on this, the embodiments of the present application provide a refrigerator screening method, device, electronic device and storage medium, aiming to provide a method for selecting and operating an analysis of a centrifugal refrigerator with multi-stage compression and multi-stage throttling cooling and its compressor, which solves the problem in the prior art that it is difficult to effectively compare the performance of refrigerators of different models and under different working conditions during the refrigerator selection process. The embodiments of the present application propose a definition of the relative energy efficiency of refrigerators, establish a corresponding mathematical model, and a method for obtaining the relative energy efficiency of different refrigerators; it can remove the influence of factors such as the external environmental parameters of the refrigerant system, the number of compression stages, the electrical and mechanical transmission systems, and only evaluate the core performance of the refrigerator body and the compressor; it can analyze the changes in the isentropic compression efficiency of the compressor at different cooling water temperatures, different refrigeration temperatures, and different refrigerator load rates, and is an effective tool for compressor selection and operation analysis.

[0023] The refrigerator screening method, device, electronic device and storage medium provided in the embodiments of the present application are specifically described through the following embodiments. First, the refrigerator screening method in the embodiments of the present application is described.

[0024] The refrigerator screening method provided in the embodiment of the present application relates to the field of refrigeration technology. The refrigerator screening method provided in the embodiment of the present application can be applied to a terminal, can be applied to a server side, or can be software running in a terminal or a server side. In some embodiments, the terminal can be a smart phone, a tablet computer, a laptop computer, a desktop computer, etc.; the server side can be configured as an independent physical server, or can be configured as a server cluster or a distributed system composed of multiple physical servers, or can be configured as a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms; the software can be an application that implements the refrigerator screening method, etc., but is not limited to the above forms.

[0025] The present application can be used in many general or special computer system environments or configurations. For example: personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, distributed computing environments including any of the above systems or devices, and the like. The present application can be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, and the like that perform specific tasks or implement specific abstract data types. The present application can also be practiced in distributed computing environments in which tasks are performed by remote processing devices connected via a communication network. In a distributed computing environment, program modules can be located in local and remote computer storage media, including storage devices.

[0026] It should be noted that in each specific embodiment of the present application, when it comes to the need to perform relevant processing based on data related to the user's identity or characteristics, such as user information, user behavior data, user historical data, and user location information, the user's permission or consent will be obtained first, and the collection, use, and processing of such data will comply with relevant laws, regulations, and standards. In addition, when the embodiment of the present application needs to obtain the user's sensitive personal information, the user's separate permission or consent will be obtained through a pop-up window or by jumping to a confirmation page. After clearly obtaining the user's separate permission or consent, the necessary user-related data for the normal operation of the embodiment of the present application will be obtained.

[0027] Figure 1 This is an optional flow chart of the refrigerator screening method provided by the embodiment of the present application, which is applied to radar. Figure 1 The method may include but is not limited to steps S100 to S400.

[0028] In step S100 , for any one of multiple types of refrigerators, actual energy efficiency and ideal energy efficiency of the refrigerator under multiple preset conditions are obtained, wherein different preset conditions include different cooling water temperatures and / or load rates.

[0029] In this embodiment, the preset conditions are different operating conditions, including at least differences in cooling water temperature and / or load rate; they can be set specifically according to the actual application scenario. For example, the cooling water temperature can be selected as 16°C, 24°C, 32°C, etc., and the load rate can be selected as 30%, 50%, 70%, 100%, etc. The actual energy efficiency is the refrigeration coefficient of the refrigerator under the corresponding preset conditions, which can be obtained through the energy efficiency matrix provided by the refrigerator manufacturer, or measured through on-site operation tests. The ideal energy efficiency is the theoretical maximum energy efficiency of the refrigerator under infinite-stage isentropic compression and infinite-stage throttling cooling conditions. It can be specifically calculated by combining the saturation temperature of the condenser and the evaporator with the thermodynamic parameters of the refrigerant, and is used to eliminate the influence of the external environmental parameters of the refrigerant system on the energy efficiency.

[0030] In one embodiment of this embodiment, the ideal cooling Expressed as formula (1): (1); In formula (1), is the specific cooling capacity for infinite-stage compression and infinite-stage throttling cooling, kJ / kg; is the isentropic compression ratio and compression work for infinite stage isentropic compression and infinite stage throttling cooling, kJ / kg. Ideal refrigeration Calculation can be performed based on the condenser and evaporator saturation temperatures.

[0031] At the same time, the actual energy efficiency of commonly used refrigerators Expressed as formula (2): (2); In formula (2), The specific cooling capacity is kJ / kg when n-stage compression, n-stage throttling and n-1-stage cooling; Input power to the refrigerator power distribution cabinet, kJ / kg. It can be provided by the manufacturer or obtained by running tests.

[0032] Step S200 , calculating according to the actual energy efficiency and ideal energy efficiency of the refrigerator under each of the preset conditions, to obtain the relative energy efficiency and isentropic compression efficiency of the refrigerator under each of the preset conditions.

[0033] In this example, after obtaining the actual and ideal energy efficiencies of the chiller under various preset conditions, the relative energy efficiency and isentropic compression efficiency were further calculated. These two metrics are key parameters for evaluating chiller performance under different operating conditions. They can isolate the impact of external environmental parameters (such as cooling water temperature and load factor) on chiller performance, enabling horizontal comparisons of different chiller models or operating conditions.

[0034] Specifically, relative energy efficiency refers to the ratio of actual energy efficiency to ideal energy efficiency. The maximum theoretical value of relative energy efficiency is 1, indicating that the refrigerator has achieved the energy efficiency level of an ideal thermodynamic cycle under these operating conditions. Relative energy efficiency can be used to assess the gap between the actual operation of the refrigerator and its ideal state, thereby judging the quality of its operating efficiency. Isentropic compression efficiency refers to the ratio of the compressor's isentropic compression work to the actual input work. It can be calculated through a comprehensive calculation of the refrigeration coefficient, compression work coefficient, and the efficiency of the inverter, motor, and bearings. It is used to assess the degree to which the compressor approaches the ideal isentropic compression process during actual operation. The isentropic compression efficiency can be used to decouple the impact of the refrigerant thermodynamic cycle on refrigerator performance, focusing on evaluating the gas dynamics performance of the compressor itself.

[0035] In one embodiment of this embodiment, the actual With ideal refrigeration The ratio is the relative energy efficiency of the refrigerator, that is, formula (3): (3); The limit value of relative energy efficiency r is 1.

[0036] Isentropic Compression Efficiency of n-stage Compression, n-stage Throttling, and n-1-stage Cooling Cycle Expressed as formula (4): (4); In formula (4), The specific compression work for n-stage isentropic compression, n-stage throttling and n-1-stage cooling is kJ / kg; The specific compression work of the compressor is expressed in kJ / kg for n-stage compression, n-stage throttling and n-1-stage cooling. For single-stage compression and two-stage compression, the specific compression work of isentropic compression is expressed as and , the isentropic compression efficiency is expressed as and . Compressor specific compression shaft work It can be expressed as formula (5): (5); In formula (5), 、 、 They are the efficiencies of the inverter, motor, mechanical transmission equipment, etc.

[0037] Refrigeration coefficient when n-stage compression, n-stage throttling and n-1-stage cooling , compression work coefficient , respectively expressed as formula (6) and formula (7): (6); (7); These two coefficients represent the effect of the total number of compression stages on the cooling capacity and specific compression work of the compressor. They can be obtained based on the total number of compression stages and the saturation temperatures of the evaporator and condenser. When the total number of compression stages is infinite, both coefficients are 1.

[0038] In formula (1) to formula (7), the cooling coefficient , compression work coefficient , isentropic compression efficiency , COP of refrigerator is related to the number of compression stages of compressor, ideal refrigeration It has nothing to do with the number of compression stages of the compressor.

[0039] According to formula (1) to formula (7), It can be expressed as formula (8): (8); It can be seen that according to the saturation temperature of the evaporator and condenser, and the total number of compression stages of the compressor, 、 、 Parameters such as refrigeration COP can be combined to obtain the relative energy efficiency r and isentropic compression efficiency Generally speaking, the inverter efficiency is 97.0~98.0%, permanent magnet motor About 97.0%, AC motor About 95.0%, the efficiency of magnetic bearing The rolling bearing efficiency is 98.0~99.8%. The range is 95.0~99.5%. 97.5%, AC motor 95.0%, magnetic bearing 98.9%, rolling bearings It is 97.3%.

[0040] Step S300: obtaining a first variation curve of the relative energy efficiency and a second variation curve of the isentropic compression efficiency of the refrigerator according to the relative energy efficiency and the isentropic compression efficiency of the refrigerator under each of the preset conditions.

[0041] In this embodiment, after calculating the relative energy efficiency and isentropic compression efficiency of the refrigerator under various preset conditions, these data are further visualized in the form of curves to obtain a first change curve of the relative energy efficiency and a second change curve of the isentropic compression efficiency.

[0042] Specifically, the first change curve and the second change curve respectively represent the law of the relative energy efficiency and the isentropic compression efficiency changing with the load rate and the cooling water temperature, and are specifically generated by fitting data points under different preset conditions, and are used to quantify the efficiency characteristics of the refrigeration machine in different operating intervals. The first change curve of the relative energy efficiency is a curve drawn with the cooling water temperature or the load rate as the horizontal coordinate and the relative energy efficiency as the vertical coordinate, reflecting the energy efficiency change of the refrigeration machine under different cooling water temperatures or load rates. The second change curve of the isentropic compression efficiency is a curve drawn with the load rate as the horizontal coordinate and the isentropic compression efficiency as the vertical coordinate, reflecting the operating efficiency change of the compressor under different cooling water temperatures or load rates.

[0043] In step S400, a target refrigeration machine is determined according to the first change curve of the relative energy efficiency and the second change curve of the isentropic compression efficiency of each type of refrigeration machine, the target refrigeration machine including at least one type of refrigeration machine selected from the plurality of types of refrigeration machines.

[0044] In the embodiment, the target refrigeration machine is determined according to the first change curve of the relative energy efficiency and the second change curve of the isentropic compression efficiency of each type of refrigeration machine, in combination with the operating requirements of the actual application scene (such as the typical cooling water temperature range, the commonly used load rate interval, etc.). The target refrigeration machine is at least one type of refrigeration machine selected from the plurality of types of refrigeration machines, and the performance of the target refrigeration machine is optimal in the preset operating condition range and can meet the actual operating requirements of the user. The target refrigeration machine refers to the optimal type selected by analyzing the high-efficiency operating interval of the relative energy efficiency curve and the peak region of the isentropic compression efficiency. Specifically, a preset temperature and load rate range can be used as a constraint condition, and the curve characteristics are matched to realize the objectification and scientization of the refrigeration machine selection.

[0045] The embodiment introduces the dual evaluation indexes of the relative energy efficiency and the isentropic compression efficiency, analyzes the change curves under the preset conditions, converts the refrigeration machine performance evaluation from the absolute energy efficiency value to the normalized parameter, eliminates the influence of the environmental parameters of the refrigerant system and the difference in the number of compressors, and thus establishes a refrigeration machine horizontal comparison and high-efficiency operating interval screening method across types and operating conditions. This evaluation method overcomes the limitations of the traditional COP index disturbed by the environmental parameters, provides a theoretical basis for the refrigeration machine selection and operating optimization, and helps to improve the overall energy efficiency and operating stability of the refrigeration system.

[0046] In some embodiments, step S100 can include but is not limited to steps S110 to S130: For any refrigeration machine in the plurality of types of refrigeration machines, the following processing is performed: For each of the preset conditions, the following processing is performed: Step S110: Obtaining an energy efficiency matrix of the refrigerator under the preset conditions, where the energy efficiency matrix of the refrigerator represents a relationship between the actual energy efficiency of the refrigerator under the preset conditions and the cooling water temperature under the preset conditions, and a relationship between the actual energy efficiency of the refrigerator under the preset conditions and the load rate under the preset conditions; Step S120, calculating the saturation temperature of the condenser and the saturation temperature of the evaporator in the refrigerator based on the energy efficiency matrix of the refrigerator under the preset conditions, the heat transfer equation of the heat exchanger, and the cooling water operation mode, wherein the cooling water operation mode is obtained based on the energy efficiency matrix of the refrigerator; Step S130 , calculating the ideal energy efficiency of the refrigerator under the preset conditions according to the saturation temperature of the condenser in the refrigerator and the saturation temperature of the evaporator in the refrigerator.

[0047] In this embodiment, the energy efficiency matrix is ​​constructed based on the measured data of the refrigerator at different cooling water temperatures and load rates to form a two-dimensional data table or functional relationship. The actual energy efficiency is usually expressed in COP, which is defined as the ratio of the cooling capacity of the refrigerator to the input electrical power. Refrigerator manufacturers usually provide COP matrices at different cooling water temperatures and load rates as part of the product performance data. The heat transfer equation of the heat exchanger includes the heat balance equation of the condenser and the heat balance equation of the evaporator. The cooling water operation mode refers to the adjustment method of the cooling water system supporting the refrigerator, including constant flow mode and constant temperature difference mode. The constant flow mode means that the cooling water flow rate remains constant, and the cooling water inlet and outlet temperature difference changes with the cooling load; the constant temperature difference mode means that the cooling water inlet and outlet temperature difference remains constant, and the flow rate is changed by adjusting the water pump frequency to adapt to the load change.

[0048] In one embodiment of this embodiment, the condenser temperature Evaporator temperature This can be obtained by calculating the heat transfer process on the cooling water side and the chilled water side. The condenser saturation temperature can be obtained based on the chiller energy efficiency matrix provided by the chiller supplier, which is a functional relationship between the chiller COP and the cooling water inlet temperature, chiller load factor, as well as the condenser heat exchange and cooling water operation mode.

[0049] For cooling water, the heat balance between any operating condition and the design operating condition is given by formula (9) and formula (10): (9); (10); In formula (9) and formula (10), is the cooling water flow rate, kg / s; is the specific heat of cooling water, kJ / kg.℃; 、 Tin, Tout, °C, are cooling water inlet and outlet temperature, respectively; COPrefis the design COP of the chiller, kW; the subscript ref represents the design condition.

[0050] Chiller part load ratio defined as equation (11): (11); In the COP matrix provided by the chiller supplier, cooling water operation is usually divided into two modes: cooling water constant flow and cooling water constant temperature difference operation. In constant flow operation, the cooling water flow is equation (12): (12); According to equations (9)~(12), the cooling water outlet temperature in constant flow operation is equation (13): (13); In cooling water constant temperature difference operation, the cooling water outlet temperature is equation (14): (14); Inside the condenser, the cooling water and the refrigerant exchange heat through copper pipes, and the heat transfer process can be represented as equations (15) and (16): (15); (16); In equations (15) and (16), Acondis the condenser copper pipe heat transfer coefficient, kW / ℃; Tcondis the condenser saturation temperature, °C.

[0051] According to equations (15) and (16), the condenser saturation temperature is equation (17): (17); For cold water, the heat balance of any condition and the design condition is equations (18) and (19): (18); (19); In equations (18) and (19), Aevap is the evaporator copper pipe heat transfer coefficient, kW / ℃; Tout, evap is the evaporator outlet temperature, °C, Tevap is the evaporator saturation temperature, °C. Thus, the evaporator saturation temperature is equation (20): (20); According to the refrigerator COP matrix, and formula (13) or formula (14), and formula (17) and formula (20), the saturation temperature of the condenser and evaporator can be obtained.

[0052] This embodiment obtains the actual energy efficiency and ideal energy efficiency of the refrigerator under various preset conditions to understand the energy efficiency level of the refrigerator under different operating conditions, providing a basis for subsequent selection and operation optimization; by combining the heat transfer equation with the operation mode, the saturation temperature of the condenser and evaporator is accurately derived, providing a reliable basis for the calculation of ideal energy efficiency; the calculation of ideal energy efficiency removes non-ideal factors such as mechanical loss and motor efficiency, providing a theoretical benchmark value for subsequent performance evaluation.

[0053] In some embodiments, step S130 may include but is not limited to steps S131 to S132: Step S131, determining the specific cooling capacity and the isentropic compression specific work of infinite-stage isentropic compression and infinite-stage throttling cooling according to the saturation temperature of the condenser in the refrigerator, the saturation temperature of the evaporator in the refrigerator, and the thermodynamic parameters of the refrigerant in the refrigerator; Step S132: Taking the ratio of the specific cooling capacity to the isentropic compression specific work as the ideal energy efficiency of the refrigerator under the preset conditions.

[0054] In this embodiment, the ideal energy efficiency is calculated based on an ideal refrigeration cycle model of infinite-stage isentropic compression and infinite-stage throttling cooling. The model assumes that: the compression process is infinite-stage isentropic compression, and the refrigerant after each stage of compression is cooled to the condensation temperature, realizing an ideal process close to isothermal compression; the throttling process is infinite-stage throttling, and the refrigerant after each stage of throttling is heat exchanged to the evaporation temperature, realizing an ideal process close to isenthalpic throttling; all irreversible factors such as flow resistance and heat dissipation loss are ignored.

[0055] In the infinite-stage compression model, the refrigerant after each stage of compression is fully cooled to the initial temperature, eliminating the impact of inter-stage temperature changes on the thermodynamic cycle. The relationship between the saturation temperature and pressure of the evaporator and condenser is established through the physical properties of the refrigerant, and the theoretical compression work is calculated by combining the enthalpy-entropy diagram of the isentropic compression process. The specific cooling capacity is characterized by the difference between the latent heat released by the complete phase change of the refrigerant in the evaporator and the sensible heat exchange in the condenser. The isentropic compression specific work is obtained by adding the isentropic enthalpy differences of each stage in the multi-stage compression process. Taking the ratio of specific cooling capacity to isentropic compression specific work as the ideal energy efficiency can eliminate the interference of actual compression stage differences on energy efficiency evaluation and realize horizontal performance comparison of refrigerators with different compression stages.

[0056] The embodiment introduces the saturated enthalpy value and other thermodynamic parameters of the refrigerant to establish a quantitative ideal energy efficiency calculation model, thereby avoiding errors in traditional empirical estimation. The ideal energy efficiency is only related to the saturated temperatures of the condenser and the evaporator and the thermal properties of the refrigerant, thereby eliminating the interference of external factors such as the cooling water temperature and the load rate. The ideal energy efficiency can be used as a benchmark for evaluating the performance of an actual refrigeration machine and helps to analyze the gap between the actual operation efficiency of the refrigeration machine and the ideal state, thereby providing an important reference for performance optimization and selection of the refrigeration machine.

[0057] In some embodiments, step S200 can include, but is not limited to, steps S210 to S230: For each of the preset conditions, the following processing is performed: Step S210, taking the ratio of the actual energy efficiency of the refrigeration machine under the preset condition to the ideal energy efficiency as the relative energy efficiency of the refrigeration machine under the preset condition; Step S220, taking the product of the refrigeration coefficient, the compression work coefficient, the frequency converter efficiency, the AC motor efficiency, and the bearing efficiency of the refrigeration machine as a first coefficient, wherein the refrigeration coefficient and the compression work coefficient are obtained according to the total compression stage number of the compressor in the refrigeration machine, the saturated temperature of the evaporator, and the saturated temperature of the condenser; Step S230, taking the ratio of the relative energy efficiency to the first coefficient as the isentropic compression efficiency.

[0058] In the embodiment, the actual energy efficiency and the ideal energy efficiency of the refrigeration machine under the preset condition are first obtained. The actual energy efficiency can be obtained through actual testing or data provided by the manufacturer, and the ideal energy efficiency can be obtained through theoretical calculation. Then, the actual energy efficiency is divided by the ideal energy efficiency to obtain the relative energy efficiency value. Then, the isentropic compression efficiency is calculated according to the parameters of the refrigeration machine. The refrigeration coefficient and the compression work coefficient can be obtained through thermodynamic calculation according to the total compression stage number of the compressor, the saturated temperature of the evaporator, and the saturated temperature of the condenser. The frequency converter efficiency, the AC motor efficiency, and the bearing efficiency can be determined according to the specific configuration of the refrigeration machine. Finally, these parameters are substituted into the calculation formula of the isentropic compression efficiency to obtain the isentropic compression efficiency of the refrigeration machine under the preset condition.

[0059] The introduction of the relative energy efficiency eliminates the influence of the external environmental parameters of the refrigerant system on the energy efficiency, and the calculation of the isentropic compression efficiency further integrates the loss parameters of the frequency converter, the motor, and the bearing to form a comprehensive efficiency index of the multi-stage compression system. The refrigeration coefficient and the compression work coefficient are associated with the compression stage number and the saturated temperature through a thermodynamic model, thereby realizing the horizontal comparability of systems with different compression stages.

[0060] Specifically, the relative energy efficiency r is the actual energy efficiency of the refrigeration machine under the current preset condition and the ideal energy efficiency The value of the relative energy efficiency is usually less than 1, and the closer the value is to 1, the closer the actual operation performance of the refrigerating machine is to the ideal cycle performance of the infinite-stage isentropic compression infinite-stage throttling cooling, and the less the refrigerating machine is affected by non-ideal factors (such as a limited compression stage number, mechanical loss, etc.).

[0061] The first coefficient is a composite parameter that comprehensively reflects the effects of the compression stage number and the transmission system efficiency on the energy efficiency. The first coefficient is the product of the refrigeration coefficient , the compression work coefficient , the frequency converter efficiency , the alternating current motor efficiency , and the bearing efficiency .

[0062] The isentropic compression efficiency is an index that reflects only the degree to which the gas compression process of the compressor approaches an isentropic process after the effects of non-core factors such as the compression stage number, the frequency converter, the motor, and the bearing are stripped. The isentropic compression efficiency can be calculated by the ratio of the relative energy efficiency r to the first coefficient. The closer the value is to 1, the better the gas dynamics performance of the compressor is, and the smaller the irreversible loss in the compression process is. For refrigerating machines with the same compression stage number, the index can be directly used to compare the core performance of the compressors. For refrigerating machines with different compression stage numbers, the index can be normalized to achieve a horizontal comparison.

[0063] In this embodiment, the first coefficient strips the non-core factors such as the compression stage number and the transmission system efficiency, so that the calculation result only reflects the gas compression performance of the compressor body, thereby providing a precise index for evaluating the design level of the compressor. The relative energy efficiency reflects the ratio of the actual performance of the refrigerating machine to the ideal performance, and eliminates the effects of external environmental factors, thereby enabling a more objective evaluation of the performance of the refrigerating machine. The isentropic compression efficiency reflects the actual efficiency of the compressor and considers various parameters of the refrigerating machine, thereby enabling a comprehensive evaluation of the performance of the compressor. The combination of the two indexes provides a more scientific and comprehensive basis for the selection and performance evaluation of the refrigerating machine.

[0064] In some embodiments, the first change curve represents a curve of the relative energy efficiency changing with the load rate at a preset cooling water temperature, and the second change curve represents a curve of the isentropic compression efficiency changing with the load rate at the preset cooling water temperature.

[0065] Step S400 can include, but is not limited to, steps S410 to S420: Step S410, for any one of a plurality of types of refrigerating machines, determining a target operation interval of the refrigerating machine according to a first change curve of the relative energy efficiency of the refrigerating machine under each of the preset conditions; Step S420, determining the target refrigerating machine according to the target operation intervals of the refrigerating machines of the various types and a second change curve of the isentropic compression efficiency.

[0066] In the present embodiment, in determining the target chiller, first, the high-efficiency operation region of each type of chiller is identified based on the relative energy efficiency curve. For each cooling water temperature, the relative energy efficiency maximum value is calculated and multiplied by a preset coefficient to obtain a dynamic threshold value, and the load rate interval higher than the threshold value is retained as the target operation interval. Subsequently, in combination with the cooling water temperature range and load rate range of the application scenario, the chiller type whose target operation interval covers the range is screened out. Finally, the chiller type with the highest efficiency in the target operation interval is selected as the target chiller by comparing the efficiency performance of the candidate types in the target operation interval through the isentropic compression efficiency curve.

[0067] Specifically, first, for each type of chiller, a first change curve of the relative energy efficiency of the chiller with respect to the load rate at a preset cooling water temperature is drawn. The first change curve refers to the relationship curve of the relative energy efficiency (r) of the chiller with respect to the load rate (PL) at a preset cooling water temperature. With the load rate (PL, usually in the range of 0-100%) as the horizontal coordinate and the relative energy efficiency (r, usually in the range of 0-1) as the vertical coordinate, the curves corresponding to different cooling water temperatures (such as 16℃, 24℃, 32℃) are drawn in the same coordinate system to obtain the first change curve.

[0068] For each type of chiller, a second change curve of the isentropic compression efficiency of the chiller with respect to the load rate at a preset cooling water temperature is drawn. The second change curve refers to the relationship curve of the isentropic compression efficiency (η) of the chiller with respect to the load rate (PL) at a preset cooling water temperature. With the load rate (PL) as the horizontal coordinate and the isentropic compression efficiency (η, usually in the range of 0-1) as the vertical coordinate, the curves corresponding to different cooling water temperatures are drawn to obtain the second change curve. For each type of chiller, a second change curve of the isentropic compression efficiency of the chiller with respect to the load rate at a preset cooling water temperature is drawn. The second change curve refers to the relationship curve of the isentropic compression efficiency (η) of the chiller with respect to the load rate (PL) at a preset cooling water temperature. With the load rate (PL) as the horizontal coordinate and the isentropic compression efficiency (η, usually in the range of 0-1) as the vertical coordinate, the curves corresponding to different cooling water temperatures are drawn to obtain the second change curve.

[0069] For any type of chiller among multiple types of chillers, the target operation interval is determined according to its first change curve (relative energy efficiency curve). The target operation interval refers to the load rate range in which the relative energy efficiency of the chiller is at a high efficiency level at a specific cooling water temperature, and this interval reflects the high-efficiency working range of the chiller. According to the energy efficiency requirements of actual applications, a relative energy efficiency threshold value (usually 90%-95% of the maximum relative energy efficiency of the chiller at the corresponding cooling water temperature) is set, and all load rate points with a relative energy efficiency value ≥ the threshold value on the first change curve are found. The continuous interval formed by these points is the target operation interval at the cooling water temperature. For the same type of chiller, repeat the above steps to obtain its target operation interval at all preset cooling water temperatures, and obtain the full-condition high-efficiency operation range of the chiller of this type.

[0070] ​The target operating interval of each type of refrigerator and the second change curve (isentropic compression efficiency curve) are compared to determine the final target refrigerator. Preferably, the type of refrigerator with a highly overlapping target operating interval and typical load rate interval of the actual application scenario is selected, and the overlap ratio of the target operating interval and the typical load rate interval is calculated. The higher the overlap ratio, the better the matching degree.

[0071] For single target refrigerator selection, the type of refrigerator with the highest matching degree of the target operating interval and the highest and most stable isentropic compression efficiency in the interval is preferably selected. For multi-target refrigerator selection (such as covering multiple working conditions), a combination of multiple types can be selected to cover the full load range of the actual application, and the isentropic compression efficiency of each type in its responsible interval is optimal.

[0072] The embodiment ensures that the selected refrigerator remains highly efficient in the actual commonly used load range through the definition of the target operating interval. Through the curve analysis at multiple cooling water temperatures, the screening result can adapt to the fluctuation of the cooling water temperature in the actual operation, improving the overall adaptability of the refrigeration system. Thus, the most suitable refrigerator type is selected according to the actual operating conditions of the user (such as cooling water temperature and load rate range).

[0073] In some embodiments, the target operating interval of the refrigerator represents the cooling water temperature of the refrigerator under each of the preset conditions when the relative efficiency is greater than a target threshold, and the target load rate interval corresponding to each of the cooling water temperatures.

[0074] Step S410 can include, but is not limited to, steps S411 to S414: For any one of the multiple types of refrigerators, the following processing is performed: For each of the preset conditions, the following processing is performed: In step S411, the maximum value of the relative energy efficiency in the first change curve under the preset condition is obtained according to the cooling water temperature under the preset condition. In step S412, the maximum value of the relative energy efficiency is multiplied by a predetermined coefficient to obtain the target threshold under the preset condition. In step S413, the interval of the load rate corresponding to the relative energy efficiency greater than the target threshold is taken as the target load rate interval corresponding to the cooling water temperature under the preset condition. In step S414, the cooling water temperature under each of the preset conditions and the target load rate interval corresponding to each of the cooling water temperatures are taken as the target operating interval of the refrigerator.

[0075] In this embodiment, the target operating range refers to the cooling water temperature of the chiller under each preset condition when the relative energy efficiency is greater than the target threshold, and the target load rate range corresponding to each cooling water temperature. For any of the multiple models of chillers, determining the target operating range includes the following steps: For each preset condition (e.g. different cooling water temperature), the following processing is performed: Obtain the first variation curve under the preset conditions (i.e., a curve showing how relative energy efficiency changes with load rate). Extract the maximum relative energy efficiency value from the first variation curve. Multiply the maximum relative energy efficiency value by a preset coefficient (e.g., 0.95) to obtain the target threshold value under the preset conditions. The load rate interval corresponding to relative energy efficiency values ​​greater than the target threshold value is used as the target load rate interval for the cooling water temperature. Record the cooling water temperature and its corresponding target load rate interval. Then, combine the cooling water temperature and its corresponding target load rate interval under each preset condition to form the target operating range for the chiller model. The target operating range can be presented in a table or graph to facilitate subsequent analysis and comparison.

[0076] In one implementation of this embodiment, Table 1 shows the COP matrix of a typical chiller (cooling water constant flow operation, design operating condition inlet and outlet temperature difference of 5°C). According to the equations in the previous steps, combined with Table 1, the relative energy efficiency r of the chiller and the isentropic compression efficiency of the compressor can be obtained. .

[0077] Table 1

[0078] Three variable frequency base load refrigerators were selected for analysis and comparison, namely variable frequency magnetic levitation single-stage compression refrigerator A, variable frequency two-stage compression refrigerator B, and variable frequency two-stage compression refrigerator C. According to the refrigerator COP matrix provided by the manufacturer, the relative energy efficiency was obtained in combination with their respective cooling water operation modes, as shown in the following figure: Figure 2 shown. Figure 2 The influence of different cooling water inlet temperatures and different cooling load rates is considered. Figure 2It can be seen that the variation curves of the three chillers are quite different, which is related to the design parameters and operation control strategy of each chiller. For chiller A, the relative energy efficiency is the highest when the design working condition is cooling water inlet temperature of 32℃ and refrigeration load rate of 100% and 90%, and the load rate decreases to 80%, the relative energy efficiency decreases greatly; when the cooling water inlet temperature is 24℃, the relative energy efficiency is the highest when the refrigeration load rate is in the range of 100~70%, and the relative energy efficiency decreases greatly when the refrigeration load rate is lower than this range; when the cooling water inlet temperature is 16℃, the relative energy efficiency is the highest when the refrigeration load rate is in the range of 90~40%, and the relative energy efficiency of other load rates is low; with the decrease of the cooling water inlet temperature, the relative energy efficiency first increases and then decreases in the area close to 100% load rate, and the relative energy efficiency increases with the decrease of the cooling water temperature in the low load rate area. From this, it can be seen that the refrigeration load rate corresponding to the maximum relative energy efficiency of this type of chiller decreases with the decrease of the cooling water inlet temperature, which shows that when the cooling water temperature is high, the chiller should be operated in the high load rate range; and when the cooling water temperature is low, the relative energy efficiency of the chiller in the low load rate range is higher, and the relative energy efficiency of the high load rate operation is lower. In the process of chiller selection, attention should be paid to the operation load rate range of the chiller in different cooling seasons, and the cooling water temperature and the corresponding load rate range should be considered at the same time. For example, for regional cooling supply system, the total cooling load is large, and the system is provided with a large number of chillers and is equipped with cold storage. It is shown in practice that the base load chiller is operated in the low load rate in the cooling season when the cooling water temperature is high, and is operated in the high load rate in the non-cooling season when the cooling water temperature is low. For the same type of chiller, in order to operate in the low load rate in the cooling season, a smaller capacity chiller needs to be designed and configured to improve the relative energy efficiency of a single chiller; or in operation, the complementary cooperation with the cold storage release power is needed to avoid the operation of the chiller in the low load rate range.

[0079] For Chiller B, when the cooling water temperature is 32°C, the load factor range corresponding to optimal relative efficiency is 100-60%. As the cooling water temperature decreases, the relative efficiency of the chiller decreases significantly at high load factors. At a 100% load factor, the relative efficiency decreases by 4.7% and 9.1% from 32°C to 24°C and from 24°C to 16°C, respectively. At low load factors, the relative efficiency improves. At a 30% load factor, the relative efficiency increases by 5.4% and 6.0% from 32°C to 24°C and from 24°C to 16°C, respectively. At a load factor of 53%, the relative efficiency is independent of the cooling water temperature. Similar to Chiller A, at high cooling water temperatures, the chiller's high relative efficiency range occurs at high load factors, making it unsuitable for operation at low load factors. At low cooling water temperatures, the chiller's highest relative efficiency occurs at around 60% load factors, with relative efficiency decreasing at load factors above or below this value. This suggests that when selecting a chiller, consider operating conditions with high cooling water temperatures or during the cooling season. This requires optimizing the number and capacity of key chillers, balancing the high daytime cooling demand with the lower nighttime demand. Alternatively, during operation, optimize the cooling load distribution, such as adjusting the number of chillers in operation to avoid operating the chillers in inefficient areas. During the non-cooling season, when cooling water temperatures are low, it's best to operate at a load factor of around 60%, and chiller selection and operating parameter optimization should also be based on this load factor.

[0080] For Chiller C, the relative energy efficiency remains high at all cooling water temperatures within the 90% to 100% load factor range. As the cooling load factor decreases, the relative efficiency at lower cooling water temperatures increases significantly, exceeding 70% in the 60% to 90% load factor range. At a 70% load factor, the relative efficiency increases by 4.9% from 32°C to 24°C, and by 2.1% from 24°C to 16°C. For cooling water temperatures of 32°C, the relative efficiency ranges from 70% to 100%. After the load factor drops below 60%, the relative efficiency shows a significant downward trend as the load factor decreases. For cooling water temperatures of 24°C and 16°C, the relative efficiency increases compared to the 32°C condition at all load factors. At 16°C, with a chiller load factor of 45%, the relative efficiency still reaches 70%. As can be seen, this model exhibits relatively good relative energy efficiency at lower cooling water temperatures, particularly in the 60-70% load factor range. However, its relative energy efficiency decreases rapidly below a load factor of 40%, so low-load operation should be avoided as much as possible. This requires comprehensive consideration during design, selection, and operation.

[0081] At a cooling water temperature of 32°C, above a 70% load factor, Chillers B and C have higher relative energy efficiency, both having a higher relative energy efficiency advantage over Chiller A. Below a 60% load factor, Chiller B has a higher relative energy efficiency advantage. At a cooling water temperature of 24°C, above a 60% load factor, Chillers A and C both have higher relative energy efficiency, both having higher relative energy efficiency than Chiller B. Below a 40% load factor, Chiller B has a higher relative energy efficiency advantage. At a cooling water temperature of 16°C, above a 50% load factor, Chillers A and C have a higher relative energy efficiency advantage. At a 40% load factor, Chillers A and B have a higher relative energy efficiency advantage. At a 30% load factor, Chiller B has a higher relative energy efficiency advantage.

[0082] Comparisons between different chiller models cannot be generalized. This example utilizes the proposed relative energy efficiency model to attempt to provide an analytical method for chiller performance selection and operation. Each chiller model has its own unique characteristics. When selecting a model, consider the year-round hourly cooling load variations, rationally allocate the number of chillers and the capacity of each chiller, and choose the chiller that best suits the system. After the system is established and operational, it is necessary to fully utilize the advantages of each chiller based on its characteristics and load variations.

[0083] Figure 3 are the maximum relative energy efficiency and corresponding cooling load rates of the above three refrigerators at different cooling water temperatures, where loadmax is the cooling load rate corresponding to the maximum relative efficiency. It can be seen that refrigerator C has a higher maximum relative energy efficiency in the cooling water temperature range of 15~32℃; in the cooling water temperature range of 18~25℃, the maximum relative energy efficiency of refrigerators A and C are equivalent, and in the cooling water temperature range of 30~32℃, the maximum energy efficiency of refrigerators B and C are equivalent. At higher cooling water temperatures, such as 32℃, the maximum relative energy efficiency of refrigerator A is lower; the maximum relative energy efficiency of refrigerator B decreases as the cooling water temperature decreases. The maximum relative energy efficiency at the same cooling water temperature reflects the highest operating performance of the refrigerator. At the same time, the corresponding refrigerator load rate needs to be considered. Only when it operates in the corresponding refrigerator load rate range at the cooling water temperature can the relative energy efficiency advantage of the refrigerator be brought into play. From Figure 3As can be seen from the chart, the chiller load factor corresponding to the maximum relative energy efficiency of chiller A varies widely, from 60% to 90%. As the cooling water temperature changes, the chiller load factor corresponding to the maximum relative energy efficiency also decreases, indicating a high degree of refinement in chiller operation and control. The chiller load factor corresponding to chiller C ranges from 70% to 80%, with a relatively narrow adjustment range. Chiller B falls between chillers A and C. Therefore, chiller A is suitable for small units and can take advantage of its high-efficiency performance when the cooling water temperature and load factor are low. Chiller C exhibits a greater relative energy efficiency advantage in the load factor range of 70% to 80%, and chiller B falls in between.

[0084] Figure 4 、 Figure 5 and Figure 6 The figure shows the high-efficiency operating areas (i.e., target operating ranges) of the three chillers A, B, and C, respectively. The orange line indicates the lower limit of the cooling load rate in the high-efficiency operating range, and the blue line indicates the upper limit. The high-efficiency operating range is defined as the load rate range that is greater than 95% of the maximum relative energy efficiency of the model. The figure shows that the high-efficiency operating areas of the three chillers are different. Figure 4 It can be seen that, related to the fine-tuning control performance of chiller A, as the cooling water temperature decreases, the lower limit of its maximum efficient operating area continues to expand toward small load rates, while the upper limit decreases to a certain extent. Based on this efficient operating area, the optimal operating area of ​​the chiller load rate can be determined according to the actual cooling water temperature during actual operation, and the system parameters of the chiller operating load rate can be met from a system level. When selecting a model, it is necessary to consider the relatively low energy efficiency of this model at a larger load rate; during operation, it is necessary to give full play to the advantages of this model at different load rates when the cooling water temperature is different. Figure 5 is the efficient operation area of ​​refrigerator B. The efficient operation area of ​​refrigerator B is relatively wide, which is consistent with the Figure 3 The maximum relative energy efficiency curve of chiller B is consistent with the relatively flat maximum relative energy efficiency curve. Compared with chillers A and C, the disadvantage of this model is its lower maximum relative energy efficiency, but within the maximum relative energy efficiency operating range of this model, it can cover a wider load rate range. Figure 6 This is the high-efficiency operating area of ​​chiller C. Compared with chillers A and B, the load rate range of its high-efficiency operating area is narrower, but the maximum relative energy efficiency corresponding to each cooling water temperature is greater than that of chillers A and B.

[0085] By determining the target operating range for each chiller, this embodiment effectively selects chillers with high relative energy efficiency within a specific cooling water temperature and load rate range. By considering the chiller's performance under different preset conditions, chiller selection is more accurate and reasonable. Furthermore, by introducing a preset coefficient to determine the target threshold, the method's flexibility and applicability are enhanced.

[0086] In some embodiments, the first change curve represents a curve of relative energy efficiency changing with load rate at a preset cooling water temperature, and the second change curve represents a curve of isentropic compression efficiency changing with load rate at the preset cooling water temperature.

[0087] Step S420 can include, but is not limited to, steps S421 to S422: Step S421, obtaining a cooling water temperature range and a load rate range in a refrigeration machine application scenario; Step S422, selecting, according to the cooling water temperature range and the load rate range, a refrigeration machine of which a target operating interval is in the cooling water temperature range and the load rate range, and an isentropic compression efficiency corresponding to a second change curve in the cooling water temperature range and the load rate range is the highest, as the target refrigeration machine.

[0088] In this embodiment, before determining the target refrigeration machine, the key parameters of the refrigeration machine application scenario need to be obtained first. The cooling water temperature range refers to the cooling water inlet temperature interval that the refrigeration machine may encounter in actual application, which is usually determined according to the climate characteristics of the application scenario and the design parameters of the cooling system. The cooling water temperature range that the refrigeration machine may encounter in actual operation can be determined according to local climate conditions, cooling tower performance, system design, etc. The load rate range refers to the load rate interval that the refrigeration machine may run in actual application, which is usually determined according to the cold load demand characteristics. The load rate range that the refrigeration machine may run in actual operation can be determined according to the cold load demand of the building or process.

[0089] For any model of refrigeration machine, the target operating interval thereof needs to meet that the cooling water temperature interval contained in the target operating interval of the refrigeration machine matches the cooling water temperature range of the application scenario; and for each temperature point in the cooling water temperature range of the application scenario, the target load rate interval corresponding to the refrigeration machine matches the load rate range of the application scenario.

[0090] For the refrigeration machines that meet the target operating interval matching condition, the isentropic compression efficiencies thereof in the cooling water temperature range and the load rate range of the application scenario are further compared. For each refrigeration machine, a second change curve of isentropic compression efficiency changing with load rate at a preset cooling water temperature is obtained. In the cooling water temperature range and the load rate range of the application scenario, the average isentropic compression efficiency of each refrigeration machine is calculated. The average isentropic compression efficiencies of the refrigeration machines of different models are compared, and the refrigeration machine with the highest efficiency is selected as the target refrigeration machine.

[0091] In one implementation manner of this embodiment, according to formula (4) and formula (8), the isentropic compression efficiency of the compressor decouples the influence of the refrigerant thermodynamic cycle on the operating performance COP of the refrigeration machine, that is, the ideal refrigeration , refrigeration coefficient , compression coefficient , the influence of the total compression stage number n of the compressor, the compressor operating characteristics, i.e. the relationship between the isentropic compression efficiency and the refrigerant flow rate, the pressure ratio, the inlet temperature, etc. are considered separately. Figure 7 , Figure 8 and Figure 9 are the isentropic compression efficiencies of the compressors of three refrigerators A, B and C, respectively. Refrigerator A has a single-stage isentropic compression efficiency of , and refrigerators B and C have double-stage isentropic compression efficiencies of .

[0092] Figure 7 is the single-stage isentropic compression efficiency of refrigerator A, Figure 7 It is shown in FIG. 4 that, when the cooling water temperature is 20-32℃, the isentropic compression efficiencies of the compressors are close to each other in the range of 90-100% load rate, and are all high, being between 88.0 and 91.7%, which indicates that, in most of the cooling water temperature range, the operating efficiency of the compressor is high at high load rate; as the load rate decreases, the isentropic compression efficiency decreases sharply in the range of 28-32℃ of the cooling water temperature, and the compressor is not suitable for operating at low load rate at high cooling water temperature; when the cooling water temperature is 24℃, the isentropic compression efficiency of the compressor remains high at a load rate of 70-100% of the refrigerator; when the cooling water temperature is 20℃, the isentropic compression efficiency of the compressor is high at a load rate of 60-100% of the refrigerator; when the cooling water temperature is 16℃, the isentropic compression efficiency curve is different from that at other cooling water temperatures, and the isentropic compression efficiency is small at high load rate, and reaches a maximum at a load rate of 60%; in the range of 60-30% load rate, the isentropic compression efficiency of the compressor increases as the cooling water temperature decreases, which indicates that the design and operation control of the compressor give priority to low cooling water temperature and low load rate.

[0093] Figure 8 is the double-stage isentropic compression efficiency curve of refrigerator B. Figure 8 It is shown in FIG. 5 that each of the isentropic compression efficiency curves at a constant cooling water temperature has a parabolic shape, the highest point of each parabola moves reversely to small load rate as the cooling water temperature decreases, the isentropic compression efficiency increases as the cooling water temperature increases at high load rate, and the isentropic compression efficiency increases as the cooling water temperature decreases at low load rate, and the five curves intersect at the same position at about a load rate of 45%. Overall, the isentropic compression efficiency curve of refrigerator B changes gently, and the change is basically in the range of 70-86.3%. When the cooling water temperature is 28 and 32℃, the isentropic compression efficiency is high at a load rate of 70-100% of the refrigerator; when the cooling water temperature is 24℃, the isentropic compression efficiency is high at a load rate of 60-80% of the refrigerator; when the cooling water temperature is 20 and 16℃, the highest isentropic compression efficiency points appear at a load rate of 70% and 60%, respectively.

[0094] Figure 9 For the double-stage isentropic compression curve of the chiller C, the isentropic compression efficiency is greater than 80% for the cooling water temperature range of 16-32℃ and the load rate of 60-100, indicating that the compressor can basically operate in the high-efficiency range at a high load rate. When the load rate is lower than 70%, the isentropic compression efficiency increases with the decrease of the cooling water temperature, and for each cooling water temperature curve, the isentropic compression efficiency decreases rapidly with the decrease of the load rate.

[0095] The isentropic compression efficiency curve of the compressor represents the design and operation control concept of the chiller model. Compared with the three chiller models, the single-stage isentropic compression efficiency of the chiller A is higher, and some curves are higher than 90% isentropic compression efficiency. The double-stage isentropic compression efficiency of the chiller C is close to the range of 90%. The isentropic compression efficiency of the chillers A and C varies in a large range, and can be less than 60% in the low isentropic compression efficiency region. Relatively speaking, except for the cooling water temperature of 32℃, the highest isentropic compression efficiency of the chiller B is not greater than that of the chillers A and C in most cooling water temperature ranges, but the lowest isentropic compression efficiency of the chiller B is greater than that of the chillers A and C. The isentropic compression efficiency curve of the chiller B varies in a small range. For the chiller A, the single-stage isentropic compression efficiency is higher than the double-stage isentropic compression efficiency of the chillers B and C, but the compression power coefficient of the double-stage compression is greater than that of the single-stage compression. The relative efficiency is shown in Figure 2 The single-stage isentropic compression efficiency and the double-stage isentropic compression efficiency both represent the operation efficiency of the compressor. If the operation performance of the chiller is compared, the contribution of the compression stage number to the COP of the chiller should be considered.

[0096] As can be seen from Figure 7~Figure 9 , the isentropic compression efficiency of the compressor represented by the chiller load rate and the cooling water temperature can reflect the operation performance of the refrigeration compressor to a certain extent, and then the performance characteristics of the compressor are obtained. Essentially, the performance characteristics of the compressor are represented by the relationship between the pressure ratio and the flow rate, which is related to the constant compressor speed, the guide vane opening degree, the diffuser opening degree, etc.

[0097] In one implementation manner of the embodiment, the relative energy efficiency of the double-working-condition chiller and the isentropic compression efficiency of the compressor can also be analyzed, including the double-working-condition fixed-frequency single-stage compression chiller D and the double-working-condition fixed-frequency double-stage compression chiller E. Each chiller is analyzed in the ice-making condition and the air-conditioning condition.

[0098] Figure 10The relative energy efficiency of two chillers, D and E, varies with chiller load factor under ice-making conditions at different cooling water temperatures. The figure shows that for each chiller, the relative energy efficiency decreases with decreasing cooling water temperature. Furthermore, for each cooling water temperature, the relative energy efficiency decreases with decreasing cooling load factor. This indicates that the chillers were designed to prioritize the design ice-making conditions (i.e., 30°C cooling water inlet temperature, -5.5 (-5.6)°C ice-making temperature, and 100% cooling load factor). Deviating from the design conditions, the relative energy efficiency of chiller E decreases to a certain extent. At the design operating point, the relative energy efficiency of chiller E is relatively high. At 100% cooling load factor and when the cooling water temperature is greater than 20°C, the relative energy efficiency of chiller E is higher than that of chiller D. As the cooling load factor decreases, the relative energy efficiency of chiller E decreases rapidly, while the relative energy efficiency of chiller D changes more gradually. This shows that Chiller E is suitable for operation near the design operating point or full load rate, and it is not advisable to reduce the cooling load rate for ice production. Chiller D, on the other hand, can operate within a wider load rate range. During design, the choice between Chiller D and Chiller E should be based on the operating conditions. If Chiller E is used, the system configuration should be designed to maximize the ability to operate Chiller E at full load. For example, the ice storage coil capacity must be precisely matched. If the capacity is too small, it may result in partial load operation during normal ice storage hours. During operation, system parameters should be adjusted to create conditions for Chiller E to operate at full load rate. Furthermore, once the return glycol temperature reaches the design operating condition of -1.8°C, it is not advisable to continue operating at a lower return glycol temperature for an extended period. If Chiller D is selected, the design allows for greater flexibility in selecting the ice storage coil capacity. During operation, the chiller can operate at temperatures below the design return glycol temperature, and its relative energy efficiency will not deviate much from the design operating conditions.

[0099] Figure 11 The relative energy efficiency curves of the two chillers under air-conditioning conditions are shown in Figure 2. Figure 10 The relative energy efficiency of the chiller decreases with the decrease of load rate and cooling water temperature. When the load rate is high, the relative energy efficiency of chiller E is higher than that of chiller D, and when the load rate is low, the relative energy efficiency is lower than that of chiller D. Figure 10 In comparison, the relative energy efficiency of the two refrigeration units in the air conditioning mode is lower than that in the ice making mode. It can be seen that when designing these two dual-mode refrigeration units, the operating performance of the ice making mode is given priority. Figure 2 In comparison, the relative energy efficiency of dual-mode fixed-frequency chillers is significantly lower than that of baseload variable-frequency chillers. Therefore, when designing an ice storage system, the number and capacity of dual-mode and baseload chillers must be comprehensively considered. The baseload variable-frequency chillers must have sufficient capacity to minimize the time the dual-mode chillers operate in air-conditioning mode. Furthermore, when operating in air-conditioning mode, the dual-mode chillers should be operated at full load as much as possible to minimize the time they operate at low load and inefficiently.

[0100] Figure 12 and Figure 13 is the isentropic compression efficiency of the dual-mode fixed-frequency single-stage compression centrifugal refrigerator D, which is divided into ice-making mode and air-conditioning mode. Figure 11 The relative efficiency trends are consistent: the isentropic compression efficiency decreases with decreasing load factor and cooling water temperature, with the slopes of both decreasing trends gradually increasing. Overall, the isentropic compression efficiency of the ice-making operation is higher than that of the air-conditioning operation. In the ice-making operation, the isentropic compression efficiency changes little with cooling water temperature, while the air-conditioning operation decreases significantly with cooling water temperature. At higher cooling water temperatures, such as 30°C and a 100% cooling load factor, the isentropic compression efficiency of the ice-making operation is 84.1%, while that of the air-conditioning operation is 78.1%. At a 50% cooling load factor, the isentropic compression efficiency of the ice-making operation is 71.0%, while that of the air-conditioning operation is 64.7%. At lower cooling water temperatures, such as 20°C and a 100% cooling load factor, the isentropic compression efficiency of the ice-making operation is 77.2%, while that of the air-conditioning operation is 60%. At a 50% cooling load factor, the isentropic compression efficiency of the ice-making operation is 64.9%, while that of the air-conditioning operation is 46.0%. It can be seen that the compressor of this model is designed to meet the operating conditions of cooling water temperature 30℃, refrigeration temperature -5.6℃, and refrigeration load rate 100%. Other operating conditions are deviations from the design conditions, and the isentropic compression efficiency of the compressor has different degrees of deviation and decrease. The deviation and decrease degree of air conditioning condition is greater than that of ice making condition.

[0101] Figure 14 and Figure 15 This is the isentropic compression efficiency curve of the dual-mode fixed-frequency two-stage compression centrifugal refrigerator E. Figure 12 and Figure 13 The same as the single-stage compression refrigerator D in the figure, the isentropic compression efficiency of the design ice-making condition with a cooling water temperature of 30°C, a refrigeration temperature of -5.6°C, and a load rate of 100% is the highest. The other conditions are all deviations from the design conditions, and the isentropic compression efficiency is reduced. Under this design condition, the isentropic compression efficiency of the compressor of refrigerator E is 80.0%. Figure 10 It can be obtained that the isentropic compression efficiency of refrigerator D is 84.1%. Considering that refrigerator D is a single-stage compression and refrigerator E is a two-stage compression, and the compression work coefficient and refrigeration coefficient contribute to the COP performance of the refrigerator in two-stage compression, the relative energy efficiency of refrigerator E is higher than that of refrigerator D, as shown in Figure 2. Figure 10 Compared with refrigerator D, the isentropic compression efficiency of refrigerator E decreases rapidly with the decrease of load rate, including all cooling water temperature ranges of ice making and air conditioning conditions. It can be seen that for different cooling water temperature ranges, this refrigerator model should be operated at 100% load rate as much as possible, which is consistent with the Figure 10 and Figure 11The conclusions from the relative energy efficiency analysis are consistent. This also reflects the differences in the design and operation control concepts of the two chiller models, which requires further analysis of the compressor characteristics, including pressure ratio, flow rate, inlet temperature, inlet guide vanes, and diffuser opening adjustment.

[0102] This embodiment establishes a dual screening mechanism of operating range and efficiency curve to ensure that the isentropic compression efficiency of the selected model is optimized under the target operating conditions, thereby maximizing the energy efficiency of the refrigeration system. This solves the problem in the existing technology that it is impossible to accurately match high-efficiency refrigerators according to the parameters of the actual application scenario, thereby avoiding the efficiency loss caused by the offset of operating condition parameters in the traditional selection process, and providing a quantitative decision-making basis for equipment matching under complex working conditions.

[0103] The embodiment of the present application proposes a normalized definition and mathematical model of the relative energy efficiency of refrigerators, effectively separating the influence of the external environmental parameters of the refrigerant system (such as cooling water temperature, refrigeration temperature, etc.) on the energy efficiency of refrigerators, and establishes a corresponding mathematical model and a method for obtaining the relative energy efficiency of different refrigerators, providing a unified benchmark for horizontal comparison of refrigerator performance under different working conditions; for refrigerators of different models (including various compression forms such as single-stage compression, two-stage compression, and three-stage compression), and different operating conditions (covering key parameters such as refrigeration temperature, cooling temperature, and refrigerator load rate), a comprehensive performance analysis and comparison is carried out through relative energy efficiency indicators, breaking through the limitation of traditional absolute energy efficiency (COP) as an indicator that is difficult to compare across working conditions and models; through the relative energy efficiency change curve, the relative energy efficiency of the refrigerator is scientifically determined. The high-efficiency operating areas under different cooling water temperatures provide clear guidance for operation optimization; for compressors with multi-stage compression and multi-stage throttling cooling, a method for obtaining the compressor isentropic compression efficiency curve is proposed. Through the obtained compressor isentropic compression efficiency curve, the changing trend of the compressor isentropic compression efficiency under different cooling water temperatures, different refrigeration temperatures, and different load rates can be systematically analyzed, and the influencing factors of the compressor core performance can be deeply revealed, providing data support for the design optimization and operation control of the compressor; through the organic combination of the above methods, a complete technical system is formed, which can provide a scientific basis for the selection decision, operation optimization, and performance evaluation of centrifugal chillers and compressors, significantly improve the energy efficiency and economy of the refrigeration system, and is an important technological innovation in the field of refrigeration equipment design, application, and operation and maintenance.

[0104] See also Figure 16 The present invention also provides a refrigerator screening device 500, which can implement the above refrigerator screening method. The device includes: an acquisition module 10 for acquiring, for any one of a plurality of models of refrigerators, actual energy efficiency and ideal energy efficiency of the refrigerator under a plurality of preset conditions, wherein different preset conditions include different cooling water temperatures and / or load rates; A first calculation module 20 is configured to calculate, based on the actual energy efficiency and ideal energy efficiency of the refrigerator under each of the preset conditions, the relative energy efficiency and isentropic compression efficiency of the refrigerator under each of the preset conditions; A second calculation module 30 is configured to obtain a first change curve of the relative energy efficiency and a second change curve of the isentropic compression efficiency of the refrigerator according to the relative energy efficiency and the isentropic compression efficiency of the refrigerator under each of the preset conditions; The screening module 40 is used to determine a target refrigerator based on a first change curve of the relative energy efficiency of each model of the refrigerator and a second change curve of the isentropic compression efficiency, wherein the target refrigerator includes at least one model of refrigerator selected from the multiple models of refrigerators.

[0105] In some embodiments, the acquisition module 10 may include: an acquisition submodule, configured to acquire an energy efficiency matrix of the refrigerator under the preset conditions, wherein the energy efficiency matrix of the refrigerator represents a relationship between the actual energy efficiency of the refrigerator under the preset conditions and the cooling water temperature under the preset conditions, and a relationship between the actual energy efficiency of the refrigerator under the preset conditions and the load rate under the preset conditions; a first calculation submodule, configured to calculate, based on an energy efficiency matrix of the refrigerator under the preset conditions, a heat transfer equation of a heat exchanger, and a cooling water operation mode, a saturation temperature of a condenser in the refrigerator and a saturation temperature of an evaporator in the refrigerator, wherein the cooling water operation mode is obtained by the energy efficiency matrix of the refrigerator; The second calculation submodule is configured to calculate the ideal energy efficiency of the refrigerator under the preset conditions according to the saturation temperature of the condenser and the saturation temperature of the evaporator.

[0106] In some embodiments, the second calculation submodule may include: a first calculation unit, configured to determine a specific cooling capacity and an isentropic compression specific work during infinite-stage isentropic compression and infinite-stage throttling cooling according to a saturation temperature of a condenser in the refrigerator, a saturation temperature of an evaporator in the refrigerator, and thermodynamic parameters of a refrigerant in the refrigerator; The second calculation unit is used to use the ratio of the specific cooling capacity to the isentropic compression specific work as the ideal energy efficiency of the refrigerator under the preset conditions.

[0107] In some embodiments, the first calculation module 20 may include: a third calculation submodule, configured to use a ratio of the actual energy efficiency of the refrigerator under the preset conditions to the ideal energy efficiency as the relative energy efficiency of the refrigerator under the preset conditions; a fourth calculation submodule, configured to use a product of a refrigeration coefficient, a compression work coefficient, an inverter efficiency, an AC motor efficiency, and a bearing efficiency of the refrigerator as a first coefficient, wherein the refrigeration coefficient and the compression work coefficient are obtained based on a total number of compression stages of a compressor in the refrigerator, a saturation temperature of an evaporator, and a saturation temperature of a condenser; A fifth calculation submodule is configured to use a ratio of the relative energy efficiency to the first coefficient as the isentropic compression efficiency.

[0108] In some embodiments, the screening module 40 may include: a first determination submodule for determining, for any one of a plurality of models of refrigerators, a target operating range of the refrigerator according to a first variation curve of the relative energy efficiency of the refrigerator under each of the preset conditions, wherein the first variation curve represents a curve in which the relative energy efficiency varies with the load rate at a preset cooling water temperature, and the second variation curve represents a curve in which the isentropic compression efficiency varies with the load rate at the preset cooling water temperature; The second determining submodule is configured to determine the target refrigerator according to the target operating range of each refrigerator model and the second variation curve of the isentropic compression efficiency.

[0109] In some implementations, the first determining submodule may include: a first acquiring unit, configured to acquire, according to the cooling water temperature under the preset conditions, a maximum value of the relative energy efficiency in the first variation curve under the preset conditions; a third calculating unit, configured to multiply the maximum value of the relative energy efficiency by a preset coefficient to obtain the target threshold value under the preset conditions; a fourth calculation unit, configured to use the load rate interval corresponding to the relative energy efficiency greater than the target threshold as the target load rate interval corresponding to the cooling water temperature under the preset conditions; The fifth calculation unit is configured to use the cooling water temperature under each of the preset conditions and the target load rate range corresponding to each of the cooling water temperatures as the target operating range of the refrigerator.

[0110] In some implementations, the second determining submodule may include: The second acquisition unit is used to obtain the cooling water temperature range and load rate range in the refrigerator application scenario; A selection unit is used to select, according to the cooling water temperature range and the load rate range, a refrigerator of multiple models whose target operating interval is within the cooling water temperature range and the load rate range and whose isentropic compression efficiency corresponding to the second change curve within the cooling water temperature range and the load rate range is the highest, as the target refrigerator.

[0111] The specific implementation of the refrigerator screening device is basically the same as the specific embodiment of the refrigerator screening method described above, and will not be repeated here.

[0112] The present application also provides an electronic device comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the above-mentioned refrigerator screening method when executing the computer program. The electronic device can be any smart terminal including a tablet computer, an in-vehicle computer, or the like.

[0113] See also Figure 17 , Figure 17 The hardware structure of an electronic device according to another embodiment is shown. The electronic device includes: The processor 801 may be implemented as a general-purpose central processing unit (CPU), a microprocessor, an 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 the present application. The memory 802 can be implemented in the form of a read-only memory (ROM), a static storage device, a dynamic storage device, or a random access memory (RAM). The memory 802 can store an 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 802 and is called by the processor 801 to execute the refrigerator screening method of the embodiments of this application. Input / output interface 803, used to implement information input and output; Communication interface 804, used to implement communication interaction between this device and other devices, which can be achieved through wired means (such as USB, network cable, etc.) or wireless means (such as mobile network, WiFi, Bluetooth, etc.); Bus 805 , which transmits information between various components of the device (e.g., processor 801 , memory 802 , input / output interface 803 , and communication interface 804 ); The processor 801 , the memory 802 , the input / output interface 803 and the communication interface 804 are connected to each other in communication within the device via a bus 805 .

[0114] An embodiment of the present application further provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the above-mentioned refrigerator screening method is implemented.

[0115] The memory, as a non-transient computer-readable storage medium, can be used to store non-transient software programs and non-transient computer executable programs. In addition, the memory may include a high-speed random access memory and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some embodiments, the memory may optionally include a memory remotely arranged relative to the processor, and these remote memories may be connected to the processor via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0116] The embodiments of the present application provide a refrigerator screening method, a refrigerator screening device, an electronic device, and a storage medium, which obtain the actual energy efficiency and ideal energy efficiency of multiple models of refrigerators under different cooling water temperatures and load rates. The actual energy efficiency and ideal energy efficiency are obtained to remove the influence of external environmental parameters on the performance of the refrigerator; the relative energy efficiency and isentropic compression efficiency under each condition are calculated based on the actual energy efficiency and the ideal energy efficiency. The relative energy efficiency reflects the actual efficiency level of the refrigerator relative to the ideal situation, and the isentropic compression efficiency quantifies the gas dynamics performance of the compressor; based on the relative energy efficiency and the isentropic compression efficiency, a first change curve of the relative energy efficiency and a second change curve of the isentropic compression efficiency are obtained. The first change curve and the second change curve respectively show the trends of the relative energy efficiency and the isentropic compression efficiency with the working conditions, and comprehensively reflect the performance characteristics of the refrigerator under different conditions; finally, the target refrigerator is determined based on the first change curve and the second change curve of each model of refrigerator. This application obtains the actual energy efficiency and ideal energy efficiency of the refrigerator under different preset conditions, calculates the relative energy efficiency and isentropic compression efficiency, generates a change curve and determines the target refrigerator. It can effectively separate the influence of external environmental parameters and energy conversion efficiency loss, provide normalized indicators, and facilitate the performance comparison of refrigerators of different models. At the same time, the isentropic compression efficiency analysis provides a theoretical basis for selection and accurately defines the high-efficiency operation range.

[0117] The embodiments described in the embodiments of 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 appreciate that with the evolution of technology and the emergence of new application scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0118] Those skilled in the art will understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of the present application, and may include more or fewer steps than shown in the figures, or a combination of certain steps, or different steps.

[0119] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, i.e., they may be located in one place or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of this embodiment.

[0120] Those skilled in the art will appreciate that all or some of the steps in the methods, systems, and functional modules / units in the devices disclosed above may be implemented as software, firmware, hardware, or appropriate combinations thereof.

[0121] The terms "first", "second", "third", "fourth", etc. (if any) in the specification of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0122] It should be understood that in this application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0123] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the above-mentioned units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0124] The units described above as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0125] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0126] If the integrated unit is implemented in the form of 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 the present application, 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, which is stored in a storage medium and includes multiple instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of various embodiments of the present application. The aforementioned storage medium includes: various media that can store programs, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0127] The preferred embodiments of the present invention are described above with reference to the accompanying drawings, but are not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and essence of the present invention should be within the scope of the present invention.

Claims

1. A refrigerator screening method, characterized in that: The method comprises: For any one of multiple models of refrigerators, obtaining actual energy efficiency and ideal energy efficiency of the refrigerator under multiple preset conditions, wherein different preset conditions include different cooling water temperatures and / or load rates; Calculating according to the actual energy efficiency and ideal energy efficiency of the refrigerator under each of the preset conditions to obtain the relative energy efficiency and isentropic compression efficiency of the refrigerator under each of the preset conditions; According to the relative energy efficiency and isentropic compression efficiency of the refrigerator under each of the preset conditions, a first change curve of the relative energy efficiency and a second change curve of the isentropic compression efficiency of the refrigerator are obtained; A target refrigerator is determined according to a first change curve of the relative energy efficiency of each model of the refrigerator and a second change curve of the isentropic compression efficiency. The target refrigerator includes at least one model of refrigerator selected from the multiple models of refrigerators.

2. The method according to claim 1, characterized in that For any refrigerator of multiple models, obtaining the actual energy efficiency and ideal energy efficiency of the refrigerator under multiple preset conditions includes: For any of the various models of refrigerators, perform the following: For each of the preset conditions, perform the following processing: Obtaining an energy efficiency matrix of the refrigerator under the preset conditions, where the energy efficiency matrix represents a relationship between the actual energy efficiency of the refrigerator under the preset conditions and the cooling water temperature under the preset conditions, and a relationship between the actual energy efficiency of the refrigerator under the preset conditions and the load rate under the preset conditions; Calculating the saturation temperature of the condenser and the saturation temperature of the evaporator in the refrigerator based on the energy efficiency matrix, heat transfer equation of the heat exchanger, and cooling water operation mode of the refrigerator under the preset conditions, wherein the cooling water operation mode is obtained by the energy efficiency matrix of the refrigerator; The ideal energy efficiency of the refrigerator under the preset conditions is calculated according to the saturation temperature of the condenser in the refrigerator and the saturation temperature of the evaporator in the refrigerator.

3. The method according to claim 2, characterized in that The calculating, based on the saturation temperature of the condenser in the refrigerator and the saturation temperature of the evaporator in the refrigerator, to obtain the ideal energy efficiency of the refrigerator under the preset conditions includes: Determining the specific cooling capacity and the isentropic compression specific work during infinite-stage isentropic compression and infinite-stage throttling cooling according to the saturation temperature of the condenser in the refrigerator, the saturation temperature of the evaporator in the refrigerator, and the thermodynamic parameters of the refrigerant in the refrigerator; The ratio of the specific cooling capacity to the isentropic compression specific work is used as the ideal energy efficiency of the refrigerator under the preset conditions.

4. The method according to claim 1, wherein The calculation is performed based on the actual energy efficiency and ideal energy efficiency of the refrigerator under each of the preset conditions to obtain the relative energy efficiency and isentropic compression efficiency of the refrigerator under each of the preset conditions, including: For each of the preset conditions, perform the following processing: The ratio of the actual energy efficiency of the refrigerator under the preset conditions to the ideal energy efficiency is used as the relative energy efficiency of the refrigerator under the preset conditions; The product of the refrigeration coefficient, compression work coefficient, inverter efficiency, AC motor efficiency, and bearing efficiency of the refrigerator is used as a first coefficient, wherein the refrigeration coefficient and the compression work coefficient are obtained based on the total number of compression stages of the compressor in the refrigerator, the saturation temperature of the evaporator, and the saturation temperature of the condenser; The ratio of the relative energy efficiency to the first coefficient is used as the isentropic compression efficiency.

5. The method according to claim 1, wherein The first variation curve represents a curve showing a change in relative energy efficiency with a load rate at a preset cooling water temperature, and the second variation curve represents a curve showing a change in isentropic compression efficiency with a load rate at a preset cooling water temperature; Determining a target refrigerator according to the first change curve of the relative energy efficiency of each refrigerator model and the second change curve of the isentropic compression efficiency includes: For any one of the multiple models of refrigerators, determining a target operating range of the refrigerator according to a first variation curve of the relative energy efficiency of the refrigerator under each of the preset conditions; The target refrigerator is determined according to the target operating range of each model of refrigerator and the second variation curve of the isentropic compression efficiency.

6. The method according to claim 5, characterized in that The target operating range of the refrigerator represents the cooling water temperature of the refrigerator under each of the preset conditions when the relative efficiency of the refrigerator is greater than a target threshold, and the target load rate range corresponding to each cooling water temperature; For any one of the multiple models of refrigerators, determining a target operating range of the refrigerator according to a first variation curve of the relative energy efficiency of the refrigerator under each of the preset conditions includes: For any of the multiple models of refrigerators, perform the following processing: For each of the preset conditions, perform the following processing: According to the cooling water temperature under the preset conditions, obtaining a maximum value of the relative energy efficiency in the first variation curve under the preset conditions; Multiplying the maximum value of the relative energy efficiency by a preset coefficient to obtain the target threshold under the preset conditions; The load rate interval corresponding to the relative energy efficiency greater than the target threshold is used as the target load rate interval corresponding to the cooling water temperature under the preset conditions; The cooling water temperature under each of the preset conditions and the target load rate range corresponding to each of the cooling water temperatures are used as the target operating range of the refrigerator.

7. The method according to claim 5, characterized in that The step of determining the target refrigerator according to the target operating range of each refrigerator model and the second change curve of the isentropic compression efficiency includes: Obtain the cooling water temperature range and load rate range for the chiller application scenario; According to the cooling water temperature range and the load rate range, a refrigerator of multiple models whose target operating interval is within the cooling water temperature range and the load rate range and whose isentropic compression efficiency corresponding to the second change curve within the cooling water temperature range and the load rate range is the highest is selected as the target refrigerator.

8. A refrigerator screening device, characterized in that: The device comprises: an acquisition module, configured to acquire, for any one of a plurality of models of refrigerators, actual energy efficiency and ideal energy efficiency of the refrigerator under a plurality of preset conditions, wherein different preset conditions include different cooling water temperatures and / or load rates; A first calculation module is configured to calculate, based on the actual energy efficiency and ideal energy efficiency of the refrigerator under each of the preset conditions, the relative energy efficiency and isentropic compression efficiency of the refrigerator under each of the preset conditions; a second calculation module, configured to obtain a first change curve of the relative energy efficiency and a second change curve of the isentropic compression efficiency of the refrigerator according to the relative energy efficiency and the isentropic compression efficiency of the refrigerator under each of the preset conditions; A screening module is used to determine a target refrigerator based on a first change curve of the relative energy efficiency of each model of the refrigerator and a second change curve of the isentropic compression efficiency, wherein the target refrigerator includes at least one model of refrigerator selected from the multiple models of refrigerators.

9. An electronic device, characterized in that: The electronic device includes a memory and a processor, the memory stores a computer program, and the processor implements the refrigerator screening method according to any one of claims 1 to 7 when executing the computer program.

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

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