Refrigerator screening method and device, electronic equipment and storage medium

Abstract

Embodiments of the present application provide a refrigeration machine screening method and device, electronic equipment and storage medium, belonging to the technical field of refrigeration. The method comprises: for any one type of refrigeration machine in a plurality of types of refrigeration machines, obtaining the actual energy efficiency and the ideal energy efficiency of the refrigeration machine under a plurality of preset conditions; calculating the relative energy efficiency and the isentropic compression efficiency of the refrigeration machine under each preset condition according to the actual energy efficiency and the ideal energy efficiency of the refrigeration machine under each preset condition; obtaining the first change curve of the relative energy efficiency and the second change curve of the isentropic compression efficiency of the refrigeration machine according to the relative energy efficiency and the isentropic compression efficiency of the refrigeration machine under each preset condition; and determining a target refrigeration machine 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 comprising at least one type of refrigeration machine selected from the plurality of types of refrigeration machines. The embodiments of the present application can provide a basis for refrigeration machine selection.

Description

Technical Field

[0001] This application relates to the field of refrigeration technology, and in particular to a refrigeration machine screening method, apparatus, electronic device and storage medium. Background Technology

[0002] Centrifugal chillers are crucial equipment in large-scale air conditioning systems and industrial refrigeration, and their energy efficiency directly impacts system operating costs and energy consumption. Currently, the main indicator for evaluating chiller energy efficiency is the coefficient of performance (COP), defined as the cooling capacity obtained per unit of input electrical work. The COP value is influenced by various factors, including cooling water temperature, chilled water temperature, the small temperature difference between the evaporator and condenser, compressor efficiency, inverter efficiency, motor efficiency, and mechanical transmission efficiency.

[0003] In practical applications, evaluating the operating efficiency of a refrigeration unit requires isolating the influence of external environmental parameters on the refrigerant system to enable horizontal comparisons of performance under different operating conditions or between different models of refrigeration units. However, the coefficient of performance (COP) is affected by the thermodynamic cycle efficiency of the refrigerant, making direct comparisons of performance under different operating conditions or between different models of refrigeration units difficult. Furthermore, commonly used definitions such as single-stage isentropic compression efficiency and variable compression efficiency are not applicable to evaluating the efficiency of multi-stage compression and multi-stage throttling cooling compressors. Therefore, refrigeration unit design and selection can easily lead to mismatches with actual requirements. Summary of the Invention

[0004] The main objective of this application is to provide a method, apparatus, electronic device, and storage medium for screening refrigerators, which can solve the problem that it is difficult to match actual needs in the screening process of refrigerators in the prior art.

[0005] To achieve the above objectives, a first aspect of this application proposes a method for screening refrigeration units, the method comprising:

[0006] For any model of refrigeration unit among a variety of models, obtain the actual energy efficiency and ideal energy efficiency of the refrigeration unit under various preset conditions, wherein the different preset conditions include different cooling water temperatures and / or load rates;

[0007] The relative energy efficiency and isentropic compression efficiency of the refrigerator under each preset condition are calculated based on the actual energy efficiency and ideal energy efficiency of the refrigerator under each preset condition.

[0008] Based on the relative energy efficiency and isentropic compression efficiency of the refrigerator under each of the preset conditions, a first variation curve of the relative energy efficiency and a second variation curve of the isentropic compression efficiency of the refrigerator are obtained.

[0009] A target refrigerator is determined based on a first variation curve of the relative energy efficiency of each model of the refrigerator and a second variation curve of the isentropic compression efficiency, wherein the target refrigerator includes at least one model of refrigerator selected from the plurality of models of refrigerators.

[0010] In some embodiments, obtaining the actual energy efficiency and ideal energy efficiency of any one of a variety of refrigerator models under various preset conditions includes:

[0011] For any one of the various models of refrigeration units, perform the following process:

[0012] For each of the preset conditions, the following processing is performed:

[0013] Obtain the energy efficiency matrix of the refrigeration unit under the preset conditions. The energy efficiency matrix of the refrigeration unit characterizes the relationship between the actual energy efficiency of the refrigeration unit under the preset conditions and the cooling water temperature under the preset conditions, as well as the relationship between the actual energy efficiency of the refrigeration unit under the preset conditions and the load rate under the preset conditions.

[0014] The saturation temperature of the condenser and the saturation temperature of the evaporator in the refrigerator are obtained by calculation 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. The cooling water operation mode is obtained through the energy efficiency matrix of the refrigerator.

[0015] The ideal energy efficiency of the refrigeration machine under the preset conditions is calculated based on the saturation temperature of the condenser and the saturation temperature of the evaporator in the refrigeration machine.

[0016] 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 in the refrigerator includes:

[0017] Based on 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, determine the specific cooling capacity and the specific work of isentropic compression under infinite-stage isentropic compression and infinite-stage throttling cooling.

[0018] The ratio of the specific cooling capacity to the isentropic compression specific work is taken as the ideal energy efficiency of the refrigerator under the preset conditions.

[0019] In some embodiments, the step of calculating the relative energy efficiency and isentropic compression efficiency of the refrigerator under each preset condition based on the actual and ideal energy efficiency of the refrigerator under each preset condition includes:

[0020] For each of the preset conditions, the following processing is performed:

[0021] The ratio of the actual energy efficiency to the ideal energy efficiency of the refrigeration unit under the preset conditions is taken as the relative energy efficiency of the refrigeration unit under the preset conditions;

[0022] The product of the refrigeration coefficient, compression work coefficient, inverter efficiency, AC motor efficiency, and bearing efficiency of the refrigeration machine is used as the first coefficient. The refrigeration coefficient and the compression work coefficient are obtained based on the total number of compression stages of the compressor in the refrigeration machine, the saturation temperature of the evaporator, and the saturation temperature of the condenser.

[0023] The ratio of the relative energy efficiency to the first coefficient is taken as the isentropic compression efficiency.

[0024] In some embodiments, the first variation curve represents the curve of relative energy efficiency changing with load rate at a preset cooling water temperature, and the second variation curve represents the curve of isentropic compression efficiency changing with load rate at a preset cooling water temperature.

[0025] The step of determining the target refrigerator based on the first variation curve of the relative energy efficiency of each model of the refrigerator and the second variation curve of the isentropic compression efficiency includes:

[0026] For any model of refrigeration machine among multiple models, the target operating range of the refrigeration machine is determined according to the first change curve of the relative energy efficiency of the refrigeration machine under each preset condition;

[0027] The target refrigerator is determined based on the target operating range of each refrigerator model and the second variation curve of isentropic compression efficiency.

[0028] In some embodiments, the target operating range of the chiller characterizes the cooling water temperature of the chiller under each preset condition when the relative efficiency of the chiller is greater than the target threshold, and the target load rate range corresponding to each cooling water temperature;

[0029] For any model of refrigeration unit among multiple models, determining the target operating range of the refrigeration unit based on the first variation curve of its relative energy efficiency under each preset condition includes:

[0030] For any model of refrigeration unit among multiple models, perform the following process:

[0031] For each of the preset conditions, the following processing is performed:

[0032] Based on the cooling water temperature under the preset conditions, obtain the maximum value of the relative energy efficiency in the first variation curve under the preset conditions;

[0033] Multiply the maximum value of the relative energy efficiency by a preset coefficient to obtain the target threshold under the preset conditions;

[0034] The range of load rates corresponding to relative energy efficiency greater than the target threshold is taken as the target load rate range corresponding to the cooling water temperature under the preset conditions.

[0035] The cooling water temperature under each preset condition, and the target load rate range corresponding to each cooling water temperature, are taken as the target operating range of the chiller.

[0036] In some embodiments, determining the target refrigerator based on the target operating range of each refrigerator model and a second variation curve of isentropic compression efficiency includes:

[0037] Obtain the cooling water temperature range and load rate range for the application scenarios of the chiller;

[0038] Based on the cooling water temperature range and the load rate range, select from multiple models the refrigerator with the highest isentropic compression efficiency corresponding to the second variation curve within the cooling water temperature range and the load rate range, and use it as the target refrigerator.

[0039] To achieve the above objectives, a second aspect of this application provides a refrigeration unit screening device, the device comprising:

[0040] The acquisition module is used to acquire the actual energy efficiency and ideal energy efficiency of any model of refrigeration machine among a variety of models under various preset conditions, wherein the different preset conditions include different cooling water temperatures and / or load rates.

[0041] The first calculation module is used to calculate the relative energy efficiency and isentropic compression efficiency of the refrigerator under each preset condition based on the actual energy efficiency and ideal energy efficiency of the refrigerator under each preset condition.

[0042] The second calculation module is used to obtain a first variation curve of the relative energy efficiency and a second variation curve of the isentropic compression efficiency of the refrigerator based on the relative energy efficiency and isentropic compression efficiency of the refrigerator under each preset condition.

[0043] A screening module is used to determine a target refrigerator based on a first variation curve of the relative energy efficiency of each type of refrigerator and a second variation curve of the isentropic compression efficiency, wherein the target refrigerator includes at least one type of refrigerator selected from the plurality of refrigerator types.

[0044] To achieve the above objectives, a third aspect of this application provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the method described in the first aspect.

[0045] To achieve the above objectives, a fourth aspect of the present application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method described in the first aspect.

[0046] The chiller screening method, apparatus, electronic equipment, and storage medium proposed in this application obtain the actual and ideal energy efficiency of various chiller models under different cooling water temperatures and load rates. Obtaining the actual and ideal energy efficiency is to isolate the influence of external environmental parameters on the chiller performance. Based on the actual and ideal energy efficiency, the relative energy efficiency and isentropic compression efficiency under each condition are calculated. The relative energy efficiency reflects the actual efficiency level of the chiller relative to the ideal situation, while the isentropic compression efficiency quantifies the gas dynamic performance of the compressor. Based on the relative energy efficiency and isentropic compression efficiency, a first variation curve of relative energy efficiency and a second variation curve of isentropic compression efficiency are obtained. The first and second variation curves respectively show the trends of relative energy efficiency and isentropic compression efficiency with operating conditions, comprehensively reflecting the performance characteristics of the chiller under different conditions. Finally, the target chiller is determined based on the first and second variation curves of each chiller model. This application obtains the actual and ideal energy efficiency of a refrigerator under different preset conditions, calculates the relative energy efficiency and isentropic compression efficiency, generates variation curves, and determines the target refrigerator. It can effectively separate the influence of external environmental parameters and energy conversion efficiency loss, provide normalized indicators, facilitate the performance comparison of different refrigerator models, and provide a theoretical basis for selection through isentropic compression efficiency analysis, and accurately define the high-efficiency operating range. Attached Figure Description

[0047] Figure 1 This is a schematic flowchart of the refrigeration unit screening method provided in the embodiments of this application;

[0048] Figure 2 This is a schematic diagram illustrating the relative energy efficiency changes of a typical base-loaded variable frequency centrifugal chiller under different operating conditions, as provided in the embodiments of this application.

[0049] Figure 3 This is a schematic diagram showing the maximum relative energy efficiency and corresponding cooling load rate of the base-load variable frequency centrifugal chiller provided in the embodiments of this application;

[0050] Figure 4 This is a schematic diagram of the high-efficiency operating zone of the refrigeration unit A provided in the embodiments of this application;

[0051] Figure 5 This is a schematic diagram of the high-efficiency operating zone of the refrigeration unit B provided in the embodiments of this application;

[0052] Figure 6 This is a schematic diagram of the high-efficiency operating zone of the refrigeration unit C provided in the embodiments of this application;

[0053] Figure 7 This is a schematic diagram of the isentropic compression efficiency of the compressor of refrigerator A provided in an embodiment of this application;

[0054] Figure 8 This is a schematic diagram of the isentropic compression efficiency of the compressor B in the refrigeration unit provided in this embodiment of the application;

[0055] Figure 9 This is a schematic diagram of the isentropic compression efficiency of the compressor C in the refrigeration unit provided in this embodiment of the application;

[0056] Figure 10 This is a schematic diagram of the relative energy efficiency (ice-making condition) of the dual-condition fixed-frequency centrifugal chiller provided in the embodiments of this application;

[0057] Figure 11 This is a schematic diagram of the relative energy efficiency (air conditioning condition) of the dual-condition fixed-frequency centrifugal chiller provided in the embodiments of this application;

[0058] Figure 12 This is a schematic diagram of the isentropic compression efficiency (ice-making condition) of the dual-condition fixed-frequency single-stage compression centrifugal refrigerator provided in the embodiments of this application;

[0059] Figure 13 This is a schematic diagram of the isentropic compression efficiency (air conditioning condition) of a dual-condition fixed-frequency single-stage compression centrifugal chiller provided in an embodiment of this application;

[0060] Figure 14 This is a schematic diagram of the isentropic compression efficiency (ice-making condition) of the dual-condition fixed-frequency two-stage compression centrifugal refrigerator provided in the embodiments of this application;

[0061] Figure 15 This is a schematic diagram of the isentropic compression efficiency (air conditioning condition) of the dual-condition fixed-frequency two-stage compression centrifugal chiller provided in the embodiments of this application;

[0062] Figure 16 This is a schematic diagram of the structure of the refrigeration unit screening device provided in the embodiments of this application;

[0063] Figure 17 This is a schematic diagram of the hardware structure of the electronic device provided in the embodiments of this application. Detailed Implementation

[0064] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0065] It should be noted that although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device or the order in the flowchart. The terms "first," "second," etc., in the specification, claims, and the aforementioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0066] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0067] The coefficient of performance (COP) of a refrigeration unit is an energy efficiency indicator that evaluates the cooling capacity output per unit of input electrical work. It depends on the cooling water and chilled water temperatures, the small temperature difference between the evaporator and condenser, compressor efficiency, and the efficiency of the inverter, motor, and mechanical transmission. Cooling water temperature, chilled water temperature, and the small temperature difference between the evaporator and condenser affect the refrigerant thermodynamic cycle efficiency, which can be referred to as the influence of external environmental parameters of the refrigerant system. Inverter efficiency, motor efficiency, and mechanical transmission efficiency affect the power loss from electrical input to the compressor shaft, which belongs to the loss of useful work input. Compressor efficiency, on the other hand, is an evaluation parameter of the compressor's gas dynamic performance, reflecting the operating efficiency and performance of the refrigeration unit itself. Isentropic compression efficiency is usually used to represent compressor efficiency, which is the ratio of isentropic compression work to the actual work done by the compressor. For the same refrigeration unit, when evaluating the difference in operating efficiency under different cooling water and chilled water temperatures, it is necessary to decouple and isolate the influence of external environmental parameters of the refrigerant system on the refrigeration unit's performance.

[0068] In practical applications, evaluating the performance of refrigeration units presents numerous technical challenges: When directly analyzing performance using the coefficient of performance (COP), its performance is significantly affected by the thermodynamic cycle efficiency determined by the temperatures of chilled and cooling water, making it impossible to directly determine the unit's energy efficiency from the COP value; the COP is an absolute energy efficiency value and has not been normalized, making direct horizontal comparisons of the performance of the same refrigeration unit under different operating conditions, or between different refrigeration units, difficult; the lack of normalized relative energy efficiency indicators makes it difficult to determine the high-efficiency operating range of different refrigeration units under different operating conditions, posing challenges to refrigeration unit selection and operational optimization; existing technologies... Commonly used definitions such as single-stage isentropic compression efficiency and polytropic compression efficiency have limitations in evaluating the efficiency of multi-stage compression and multi-stage throttling cooling compressors. 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 refrigeration machine design and selection stage, there is a lack of clear theoretical basis for the selection of the number of compression stages (such as single-stage compression versus two-stage compression) and the performance comparison between base-load refrigeration machines and dual-condition refrigeration machines. When analyzing the design and operating performance data of refrigeration machines, there is a lack of effective tools to accurately evaluate the core performance of the compressor.

[0069] Based on this, embodiments of this application provide a method, apparatus, electronic device, and storage medium for screening refrigeration units, aiming to provide a method for selecting and analyzing the operation of a multi-stage compression and multi-stage throttling cooling centrifugal refrigeration unit and its compressor. This solves the problem in the prior art that it is difficult to effectively compare the performance of different models and under different operating conditions during the refrigeration unit selection process. Embodiments of this application propose a definition of relative energy efficiency of refrigeration units, establish a corresponding mathematical model, and methods for obtaining the relative energy efficiency of different refrigeration units. It can isolate the influence of external environmental parameters of the refrigerant system, the number of compression stages, and electrical and mechanical transmission systems, and evaluate only the core performance of the refrigeration unit and compressor. It can analyze the changes in the isentropic compression efficiency of the compressor under different cooling water temperatures, different refrigeration temperatures, and different refrigeration unit load rates, making it an effective tool for compressor selection and operation analysis.

[0070] The chiller screening method, apparatus, electronic device and storage medium provided in the embodiments of this application are specifically described through the following embodiments. First, the chiller screening method in the embodiments of this application is described.

[0071] The refrigerator screening method provided in this application relates to the field of refrigeration technology. This refrigerator screening method can be applied to a terminal, a server, or software running on either a terminal or a server. In some embodiments, the terminal can be a smartphone, tablet, laptop, desktop computer, etc.; the server can be configured as an independent physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms; the software can be an application implementing the refrigerator screening method, but is not limited to the above forms.

[0072] This application can be used in a wide variety of general-purpose or special-purpose computer system environments or configurations. Examples include: 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, and distributed computing environments including any of the above systems or devices. This 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, etc., that perform specific tasks or implement specific abstract data types. This application can also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.

[0073] It should be noted that in all specific embodiments of this application, when processing data related to user identity or characteristics, such as user information, user behavior data, user historical data, and user location information, user permission or consent is obtained first. Furthermore, the collection, use, and processing of this data comply with relevant laws, regulations, and standards. In addition, when embodiments of this application require access to sensitive personal information of users, separate permission or consent from the user is obtained through pop-ups or redirection to confirmation pages. Only after obtaining the user's separate permission or consent is the necessary user-related data required for the proper functioning of these embodiments acquired.

[0074] Figure 1 This is an optional flowchart of the chiller screening method provided in the embodiments of this application. The embodiments of this application are applied to radar. Figure 1 The method may include, but is not limited to, steps S100 to S400.

[0075] Step S100: For any model of refrigeration unit among multiple models, obtain the actual energy efficiency and ideal energy efficiency of the refrigeration unit under multiple preset conditions, wherein the different preset conditions include different cooling water temperatures and / or load rates.

[0076] In this embodiment, the preset conditions are different operating conditions, including at least differences in cooling water temperature and / or load rate; the specific settings can be adjusted according to the actual application scenario. For example, the cooling water temperature can be selected as 16℃, 24℃, 32℃, etc., and the load rate can be selected as 30%, 50%, 70%, 100%, etc. The actual energy efficiency is the coefficient of performance (COP) of the refrigeration unit under the corresponding preset conditions, which can be obtained from the energy efficiency matrix provided by the refrigeration unit manufacturer or measured through on-site operation testing. The ideal energy efficiency is the theoretical maximum energy efficiency of the refrigeration unit under infinite isentropic compression and infinite throttling cooling conditions, which can be calculated by combining the saturation temperatures of the condenser and evaporator with the thermodynamic parameters of the refrigerant, and is used to eliminate the influence of external environmental parameters of the refrigerant system on energy efficiency.

[0077] In one embodiment of this example, ideal refrigeration Represented as formula (1):

[0078] (1);

[0079] In formula (1), Specific refrigeration capacity when using infinite-stage compression and infinite-stage throttling cooling, kJ / kg; The isentropic compression ratio and compression work (kJ / kg) under infinite-stage isentropic compression and infinite-stage throttling cooling. Ideal refrigeration. It can be calculated based on the saturation temperature of the condenser and evaporator.

[0080] Meanwhile, the actual energy efficiency of commonly used refrigeration units Represented as formula (2):

[0081] (2);

[0082] In formula (2), Specific refrigeration capacity, kJ / kg, for n-stage compression, n-stage throttling, and n-1-stage cooling. Input electrical power (kJ / kg) to the refrigeration unit's electrical distribution cabinet. Actual power input to the refrigeration unit. It can be provided by the manufacturer or obtained through operational testing.

[0083] Step S200: Calculate the relative energy efficiency and isentropic compression efficiency of the refrigerator under each preset condition based on the actual energy efficiency and ideal energy efficiency of the refrigerator under each preset condition.

[0084] In this embodiment, after obtaining the actual and ideal energy efficiency of the chiller under various preset conditions, the relative energy efficiency and isentropic compression efficiency are further calculated. These two indicators are key parameters for evaluating the operating performance of the chiller under different operating conditions. They can isolate the influence of external environmental parameters (such as cooling water temperature and load rate) on the performance of the chiller, thereby enabling a horizontal comparison of different models of chillers or different operating conditions.

[0085] Specifically, relative energy efficiency (REE) refers to the ratio of actual energy efficiency to ideal energy efficiency. The maximum theoretical value of REE is 1, indicating that the refrigeration unit has reached the energy efficiency level of an ideal thermodynamic cycle under that operating condition. REE allows us to assess the gap between the actual operation of the refrigeration unit and its ideal state, thereby judging its operational efficiency. Isentropic compression efficiency refers to the ratio of the compressor's isentropic compression work to the actual input work. It can be calculated by comprehensively considering the coefficient of performance (COP), compression work coefficient, and the efficiencies of the inverter, motor, and bearings. REE is used to assess how close the compressor is to the ideal isentropic compression process during actual operation. By using REE, we can decouple the influence of the refrigerant thermodynamic cycle on the refrigeration unit's performance, focusing on evaluating the compressor's own gas dynamic performance.

[0086] In one embodiment of this example, the actual chiller is taken as... With ideal cooling The ratio is the relative energy efficiency of the refrigeration unit, i.e., formula (3):

[0087] (3);

[0088] The limit value for relative energy efficiency r is 1.

[0089] isentropic compression efficiency of an n-stage compression, n-stage throttling, and n-1-stage cooling cycle Represented as formula (4):

[0090] (4);

[0091] In formula (4), The specific compression work, kJ / kg, is given when n-stage isentropic compression, n-stage throttling, and n-1-stage cooling are used; The compressor specific shaft work, in kJ / kg, is given by the formula for compressors with n-stage compression, n-stage throttling, and n-1-stage cooling. For single-stage and two-stage compression, the isentropic compression specific work is expressed as... and The isentropic compression efficiency is expressed as and The compressor's specific shaft work This can be expressed as formula (5):

[0092] (5);

[0093] In formula (5), , , These refer to the efficiency of frequency converters, motors, mechanical transmission equipment, etc.

[0094] Coefficient of performance for n-stage compression, n-stage throttling, and n-1-stage cooling Compression work coefficient These are expressed as formulas (6) and (7) respectively:

[0095] (6);

[0096] (7);

[0097] These two coefficients represent the influence of the total number of compression stages on the specific cooling capacity and specific compression work, and can both 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 infinitely large, both coefficients are 1.

[0098] In formulas (1) to (7), the coefficient of performance (COP) is... Compression work coefficient isentropic compression efficiency The COP of a refrigeration unit is related to the number of compression stages of the compressor. Ideal refrigeration... It is independent of the number of compression stages of the compressor.

[0099] According to formulas (1) to (7), This can be expressed as formula (8):

[0100] (8);

[0101] Therefore, it can be seen that the saturation temperatures of the evaporator and condenser, as well as the total number of compression stages of the compressor, are used to obtain... , , By combining these parameters with the COP of the refrigerator, we can obtain the relative energy efficiency r and the isentropic compression efficiency. Generally speaking, the efficiency of a frequency converter is... The percentage is 97.0% to 98.0% for permanent magnet motors. Approximately 97.0%, AC motor The efficiency of magnetic levitation bearings is approximately 95.0%. The efficiency of rolling bearings is 98.0% to 99.8%. The value is 95.0% to 99.5%. This article uses... 97.5% for AC motors 95.0% of magnetic levitation bearings The success rate was 98.9% for rolling bearings. It is 97.3%.

[0102] Step S300: Based on the relative energy efficiency and isentropic compression efficiency of the refrigerator under each preset condition, obtain the first variation curve of the relative energy efficiency and the second variation curve of the isentropic compression efficiency of the refrigerator.

[0103] 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 the first change curve of relative energy efficiency and the second change curve of isentropic compression efficiency.

[0104] Specifically, the first and second variation curves characterize the changes in relative energy efficiency and isentropic compression efficiency with load rate and cooling water temperature, respectively. These curves are generated by fitting data points under different preset conditions to quantify the efficiency characteristics of the refrigeration unit in different operating ranges. The first variation curve for relative energy efficiency is plotted with cooling water temperature or load rate on the x-axis and relative energy efficiency on the y-axis, reflecting the energy efficiency changes of the refrigeration unit under different cooling water temperatures or load rates. The second variation curve for isentropic compression efficiency is plotted with load rate on the x-axis and isentropic compression efficiency on the y-axis, reflecting the operating efficiency changes of the compressor under different cooling water temperatures or load rates.

[0105] Step S400: Determine a target refrigerator based on the first variation curve of the relative energy efficiency of each type of refrigerator and the second variation curve of the isentropic compression efficiency. The target refrigerator includes at least one type of refrigerator selected from the multiple types of refrigerators.

[0106] In this embodiment, a target chiller is determined based on the first variation curve of relative energy efficiency and the second variation curve of isentropic compression efficiency for each type of chiller, combined with the operational requirements of the actual application scenario (such as typical cooling water temperature range, common load rate range, etc.). The target chiller is at least one type of chiller selected from multiple types, whose performance is optimal within a preset operating range and can meet the user's actual operational needs. The target chiller refers to the optimal model selected by analyzing the high-efficiency operating range of the relative energy efficiency curve and the peak region of the isentropic compression efficiency. Specifically, preset temperature and load rate ranges can be used as constraints, combined with curve characteristics for matching, to achieve objectivity and scientific refrigeration selection.

[0107] This embodiment introduces dual evaluation indicators of relative energy efficiency and isentropic compression efficiency, combined with the analysis of variation curves under preset conditions, to transform the performance evaluation of refrigeration machines from absolute energy efficiency values ​​to normalized parameters. This eliminates the influence of external environmental parameters of the refrigerant system and differences in compressor stages, thereby establishing a method for cross-model and cross-operating condition comparison of refrigeration machines and selection of high-efficiency operating ranges. This evaluation method overcomes the limitations of traditional COP indicators that are affected by environmental parameters, providing a theoretical basis for refrigeration machine selection and operation optimization, and helping to improve the overall energy efficiency and operational stability of refrigeration systems.

[0108] In some embodiments, step S100 may include, but is not limited to, steps S110 to S130:

[0109] For any one of the various models of refrigeration units, perform the following process:

[0110] For each of the preset conditions, the following processing is performed:

[0111] Step S110: Obtain the energy efficiency matrix of the chiller under the preset conditions. The energy efficiency matrix of the chiller represents the relationship between the actual energy efficiency of the chiller under the preset conditions and the cooling water temperature under the preset conditions, as well as the relationship between the actual energy efficiency of the chiller under the preset conditions and the load rate under the preset conditions.

[0112] Step S120: Calculate 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. The cooling water operation mode is obtained through the energy efficiency matrix of the refrigerator.

[0113] Step S130: Calculate the ideal energy efficiency of the refrigeration unit under the preset conditions based on the saturation temperature of the condenser and the saturation temperature of the evaporator in the refrigeration unit.

[0114] In this embodiment, the energy efficiency matrix is ​​constructed based on measured data of the chiller at different cooling water temperatures and load rates, forming a two-dimensional data table or functional relationship. Actual energy efficiency is usually expressed as COP, defined as the ratio of the chiller's cooling capacity to its input electrical power. Chip manufacturers typically provide COP matrices for different cooling water temperatures and load rates as part of their product performance data. The heat exchanger heat transfer equations include the condenser's heat balance equation and the evaporator's heat balance equation. The cooling water operation mode refers to the adjustment method of the chiller's cooling water system, including constant flow mode and constant temperature difference mode. Constant flow mode means the cooling water flow rate remains constant, and the temperature difference between the cooling water inlet and outlet changes with the cooling load; constant temperature difference mode means the temperature difference between the cooling water inlet and outlet remains constant, and the flow rate is adjusted by regulating the pump frequency to adapt to load changes.

[0115] In one embodiment of this example, the condenser temperature With evaporator temperature The saturation temperature of the condenser can be obtained by calculating the heat transfer processes on the cooling water and chilled water sides. Based on the energy efficiency matrix of the refrigeration unit provided by the refrigeration unit supplier, which shows the functional relationship between the refrigeration unit's COP and the cooling water inlet temperature and the refrigeration unit's load rate, as well as the heat exchange situation of the condenser and the cooling water operating mode, the condenser saturation temperature can be obtained.

[0116] For cooling water, the heat balance between any operating condition and the design operating condition is given by formulas (9) and (10):

[0117] (9);

[0118] (10);

[0119] In formulas (9) and (10), The flow rate is the cooling water flow rate, expressed in kg / s. The specific heat of cooling water is expressed in kJ / kg·℃. , These are the inlet and outlet temperatures of the cooling water, respectively, in °C. The cooling capacity of the refrigeration unit is expressed in kW; the subscript ref indicates the design operating condition.

[0120] Refrigeration unit partial load rate Defined as formula (11):

[0121] (11);

[0122] In the COP matrix provided by the chiller supplier, cooling water operation is usually divided into two modes: constant flow rate and constant temperature difference operation. In constant flow rate operation, the cooling water flow rate is given by formula (12):

[0123] (12);

[0124] According to formulas (9) to (12), the outlet temperature of the cooling water for constant flow operation can be obtained as formula (13):

[0125] (13);

[0126] When the cooling water operates at a constant temperature difference, the cooling water outlet temperature is given by formula (14):

[0127] (14);

[0128] Inside the condenser, cooling water and refrigerant exchange heat through copper tubes. The heat transfer process can be expressed by formulas (15) and (16):

[0129] (15);

[0130] (16);

[0131] In formulas (15) and (16), The value is the heat transfer coefficient of the condenser copper tubes, in kW / ℃; The saturation temperature of the condenser is ℃.

[0132] According to formulas (15) and (16), the saturation temperature of the condenser can be obtained as formula (17):

[0133] (17);

[0134] For cold water, the heat balance between any operating condition and the design operating condition is given by formulas (18) and (19):

[0135] (18);

[0136] (19);

[0137] In formulas (18) and (19), The value is the heat transfer coefficient of the evaporator copper tubes, expressed in kW / ℃. Evaporator outlet temperature, °C Let be the saturation temperature of the evaporator, in °C. Therefore, the saturation temperature of the evaporator can be obtained using formula (20):

[0138] (20);

[0139] Based on the COP matrix of the refrigeration unit, and formulas (13) or (14), as well as formulas (17) and (20), the saturation temperatures of the condenser and evaporator can be obtained.

[0140] This embodiment obtains the actual and ideal energy efficiency of the refrigeration unit under various preset conditions to understand the energy efficiency level of the refrigeration unit under different operating conditions, providing a basis for subsequent selection and operation optimization. By combining the heat transfer equation with the operating 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 excludes non-ideal factors such as mechanical losses and motor efficiency, providing a theoretical benchmark value for subsequent performance evaluation.

[0141] In some embodiments, step S130 may include, but is not limited to, steps S131 to S132:

[0142] Step S131: Based on 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, determine the specific cooling capacity and the specific work of isentropic compression under infinite-stage isentropic compression and infinite-stage throttling cooling.

[0143] Step S132: The ratio of the specific cooling capacity to the isentropic compression specific work is taken as the ideal energy efficiency of the refrigerator under the preset conditions.

[0144] 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. This 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, achieving an ideal process close to isothermal compression; the throttling process is infinite-stage throttling, and the refrigerant after each stage of throttling undergoes heat exchange to the evaporation temperature, achieving an ideal process close to isenthalpic throttling; and all irreversible factors such as flow resistance and heat dissipation loss are ignored.

[0145] In the infinite-stage compression model, the refrigerant after each compression stage is fully cooled to its initial temperature, eliminating the influence of interstage temperature changes on the thermodynamic cycle. The saturation temperature and pressure relationship between the evaporator and condenser is established using refrigerant property parameters, and the theoretical compression work is calculated using the enthalpy-entropy diagram of the isentropic compression process. Specific cooling capacity is characterized by the difference between the latent heat released during 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 accumulating the isentropic enthalpy difference of each stage in the multi-stage compression process. Using the ratio of specific cooling capacity to isentropic compression specific work as the ideal energy efficiency eliminates the interference of actual compression stage differences on energy efficiency evaluation, enabling a cross-sectional performance comparison of refrigerators with different compression stages.

[0146] This embodiment establishes a quantitative ideal energy efficiency calculation model by introducing thermodynamic parameters such as the saturation enthalpy of the refrigerant, avoiding the errors of traditional empirical estimation. The ideal energy efficiency is only related to the saturation temperature of the condenser and evaporator and the thermophysical properties of the refrigerant, eliminating the interference of external factors such as cooling water temperature and load rate. The ideal energy efficiency can serve as a benchmark for evaluating the actual performance of the refrigeration machine, helping to analyze the gap between the actual operating efficiency of the refrigeration machine and the ideal state, and providing an important reference for the performance optimization and selection of the refrigeration machine.

[0147] In some embodiments, step S200 may include, but is not limited to, steps S210 to S230:

[0148] For each of the preset conditions, the following processing is performed:

[0149] Step S210: The ratio of the actual energy efficiency to the ideal energy efficiency of the refrigeration unit under the preset conditions is taken as the relative energy efficiency of the refrigeration unit under the preset conditions;

[0150] Step S220: The product of the refrigeration coefficient, compression work coefficient, inverter efficiency, AC motor efficiency, and bearing efficiency of the refrigeration machine is used as the first coefficient. The refrigeration coefficient and the compression work coefficient are obtained based on the total number of compression stages of the compressor in the refrigeration machine, the saturation temperature of the evaporator, and the saturation temperature of the condenser.

[0151] Step S230: The ratio of the relative energy efficiency to the first coefficient is taken as the isentropic compression efficiency.

[0152] In this embodiment, the actual and ideal energy efficiency of the refrigeration unit under preset conditions are first obtained. The actual energy efficiency can be obtained through actual testing or data provided by the manufacturer, while the ideal energy efficiency can be calculated theoretically. Then, the actual energy efficiency is divided by the ideal energy efficiency to obtain the relative energy efficiency value. Next, the isentropic compression efficiency is calculated based on various parameters of the refrigeration unit. The coefficient of performance (COP) and the compression work coefficient can be obtained through thermodynamic calculations based on the total number of compression stages of the compressor and the saturation temperatures of the evaporator and condenser. The inverter efficiency, AC motor efficiency, and bearing efficiency can be determined based on the specific configuration of the refrigeration unit. Finally, these parameters are substituted into the formula for calculating the isentropic compression efficiency to obtain the isentropic compression efficiency of the refrigeration unit under the preset conditions.

[0153] The introduction of relative energy efficiency eliminates the influence of external environmental parameters on the energy efficiency of the refrigerant system, while the calculation of isentropic compression efficiency further integrates the loss parameters of the inverter, motor, and bearings, forming a comprehensive efficiency index for multi-stage compression systems. The coefficient of performance (COP) and the coefficient of performance (COP) are established with respect to the number of compressor stages and saturation temperature through a thermodynamic model, achieving horizontal comparability of systems with different compression stages.

[0154] Specifically, the relative energy efficiency r is the actual energy efficiency of the refrigeration unit under the current preset conditions. Compared to ideal energy efficiency The ratio of the relative energy efficiency is usually less than 1. The closer the value is to 1, the closer the actual operating performance of the refrigeration unit is to the ideal cycle performance of infinite isentropic compression and infinite throttling cooling, and the less affected it is by non-ideal factors (such as finite compression stages, mechanical losses, etc.).

[0155] The first coefficient is a composite parameter that comprehensively reflects the impact of compression stage number and transmission system efficiency on energy efficiency. The first coefficient is the coefficient of performance (COP). Compression work coefficient Inverter efficiency AC motor efficiency bearing efficiency The product of.

[0156] Isentropic compression efficiency is an indicator that reflects the degree to which the gas compression process of a compressor approaches an isentropic process after removing the influence of non-core factors such as the number of compression stages, frequency converter, motor, and bearings. It can be calculated by the ratio of relative energy efficiency (r) to the first coefficient. The closer the value is to 1, the better the gas dynamic performance of the compressor and the smaller the irreversible losses in the compression process. For refrigerators with the same number of compression stages, this indicator can be directly used to compare the core performance of the compressors. For refrigerators with different numbers of compression stages, this indicator can be normalized to achieve a horizontal comparison.

[0157] This embodiment eliminates non-core factors such as the number of compression stages and transmission system efficiency through the first coefficient, ensuring that the calculation results only reflect the gas compression performance of the compressor itself, providing an accurate indicator for evaluating the compressor's design level. Relative energy efficiency reflects the ratio of the actual performance to the ideal performance of the refrigeration unit, eliminating the influence of external environmental factors and enabling a more objective evaluation of the refrigeration unit's performance. Isentropic compression efficiency reflects the actual efficiency of the compressor, taking into account various parameters of the refrigeration unit, and can comprehensively evaluate the compressor's performance. The combined use of these two indicators provides a more scientific and comprehensive basis for the selection and performance evaluation of refrigeration units.

[0158] In some embodiments, the first variation curve represents the curve of relative energy efficiency changing with load rate at a preset cooling water temperature, and the second variation curve represents the curve of isentropic compression efficiency changing with load rate at a preset cooling water temperature.

[0159] Step S400 may include, but is not limited to, steps S410 to S420:

[0160] Step S410: For any model of refrigeration machine among multiple models, determine the target operating range of the refrigeration machine based on the first change curve of the relative energy efficiency of the refrigeration machine under each preset condition;

[0161] Step S420: Determine the target refrigerator based on the target operating range of each refrigerator model and the second variation curve of isentropic compression efficiency.

[0162] In this embodiment, when determining the target chiller, the high-efficiency operating range of each chiller model is first identified based on the relative energy efficiency curve. For each cooling water temperature, the maximum relative energy efficiency is calculated and multiplied by a preset coefficient to obtain a dynamic threshold. The load rate range above the threshold is retained as the target operating range. Subsequently, combined with the cooling water temperature range and load rate range of the application scenario, chiller models whose target operating range covers this range are selected. Finally, the efficiency performance of candidate models in the target operating range is compared using isentropic compression efficiency curves, and the model with the highest efficiency is selected as the target chiller.

[0163] Specifically, firstly, for each model of refrigeration unit, a first variation curve of its relative energy efficiency as a function of load rate at a preset cooling water temperature is plotted. The first variation curve refers to the relationship between the relative energy efficiency (r) of the refrigeration unit and the load rate (PL) at the preset cooling water temperature. With the load rate (PL, typically ranging from 0 to 100%) as the abscissa and the relative energy efficiency (r, typically ranging from 0 to 1) as the ordinate, curves corresponding to different cooling water temperatures (such as 16℃, 24℃, and 32℃) are plotted on the same coordinate system to obtain the first variation curve.

[0164] For each type of refrigeration unit, a second curve was plotted showing the isentropic compression efficiency as a function of load rate at a preset cooling water temperature. The second curve represents the isentropic compression efficiency of the refrigeration unit at the preset cooling water temperature. The curve showing the relationship between load factor (PL) and compression ratio. With load factor (PL) as the horizontal axis, the isentropic compression efficiency (...) Using the value (usually ranging from 0 to 1) as the ordinate, plot the curves corresponding to different cooling water temperatures to obtain the second variation curve.

[0165] For any model of a refrigerator, the target operating range is determined based on its first variation curve (relative energy efficiency curve). The target operating range refers to the load rate range within which the refrigerator's relative energy efficiency is at a high efficiency level at a specific cooling water temperature. This range reflects the refrigerator's high-efficiency operating range. Based on the energy efficiency requirements of the actual application, a relative energy efficiency threshold is set (usually 90%~95% of the maximum relative energy efficiency of the refrigerator model at the corresponding cooling water temperature). On the first variation curve, all load rate points with relative energy efficiency values ​​≥ the threshold are identified. The continuous interval formed by these points is the target operating range at that cooling water temperature. For the same model of refrigerator, the above steps are repeated to obtain its target operating range at all preset cooling water temperatures, thus obtaining the high-efficiency operating range of the refrigerator model under all operating conditions.

[0166] By comprehensively comparing the target operating range and the second variation curve (isentropic compression efficiency curve) of various refrigerator models, the final target refrigerator model is determined. Priority is given to models whose target operating range highly overlaps with the typical load rate range of the actual application scenario. The overlap ratio between the target operating range and the typical load rate range is calculated. The higher the overlap ratio, the better the matching degree.

[0167] For single-objective refrigerator selection, the model with the highest matching degree to the target operating range and the highest and most stable isentropic compression efficiency within that range should be prioritized. For multi-objective refrigerator selection (such as when multiple operating conditions need to be covered), a combination of multiple models can be selected so that their target operating ranges collectively cover the full load range of the actual application, and each model has the optimal isentropic compression efficiency within its assigned range.

[0168] This embodiment ensures that the selected chiller maintains efficient operation within the commonly used load range by defining the target operating range; by analyzing the curves under multiple cooling water temperatures, the screening results can adapt to the fluctuations in cooling water temperature during actual operation, thus improving the overall adaptability of the refrigeration system; thereby selecting the most suitable chiller model based on the user's actual operating conditions (such as cooling water temperature and load rate range).

[0169] In some embodiments, the target operating range of the chiller represents the cooling water temperature of the chiller under each preset condition when the relative efficiency of the chiller is greater than the target threshold, and the target load rate range corresponding to each cooling water temperature.

[0170] Step S410 may include, but is not limited to, steps S411 to S414:

[0171] For any model of refrigeration unit among multiple models, perform the following process:

[0172] For each of the preset conditions, the following processing is performed:

[0173] Step S411: Based on the cooling water temperature under the preset conditions, obtain the maximum value of the relative energy efficiency in the first variation curve under the preset conditions;

[0174] Step S412: Multiply the maximum value of the relative energy efficiency by a preset coefficient to obtain the target threshold under the preset conditions;

[0175] Step S413: The range of load rates corresponding to relative energy efficiency greater than the target threshold is taken as the target load rate range corresponding to the cooling water temperature under the preset conditions.

[0176] Step S414: The cooling water temperature under each preset condition, and the target load rate range corresponding to each cooling water temperature, are taken as the target operating range of the chiller.

[0177] In this embodiment, the target operating range refers to the cooling water temperature of the chiller under each preset condition, and the target load rate range corresponding to each cooling water temperature, provided that the relative energy efficiency is greater than the target threshold. Determining the target operating range for any model of chiller from among multiple models includes the following steps:

[0178] For each preset condition (such as different cooling water temperatures), perform the following process:

[0179] Obtain the first variation curve (i.e., the curve of relative energy efficiency changing with load rate) under the preset conditions; extract the maximum value of relative energy efficiency from the first variation curve; multiply the maximum value of relative energy efficiency by a preset coefficient (e.g., 0.95) to obtain the target threshold under the preset conditions; take the load rate range corresponding to the relative energy efficiency greater than the target threshold as the target load rate range at the cooling water temperature; record the cooling water temperature and its corresponding target load rate range. Then, integrate the cooling water temperature and its corresponding target load rate range under each preset condition to form the target operating range of this type of chiller. The target operating range can be presented in the form of a table or graph for easy subsequent analysis and comparison.

[0180] In one implementation of this embodiment, Table 1 shows the COP matrix of a typical chiller (cooling water constant flow operation, design inlet and outlet temperature difference of 5℃). Based on the equations in the preceding steps and in conjunction with Table 1, the relative energy efficiency r of the chiller and the isentropic compression efficiency of the compressor can be obtained. .

[0181] Table 1

[0182]

[0183] Three variable frequency base-load chillers were selected for analysis and comparison: variable frequency magnetic levitation single-stage compression chiller A, variable frequency two-stage compression chiller B, and variable frequency two-stage compression chiller C. Based on the COP matrix provided by the manufacturer and their respective cooling water operating modes, the relative energy efficiency was obtained, such as... Figure 2 As shown. Figure 2 The effects of different cooling water inlet temperatures and different cooling load rates were considered. Figure 2As can be seen, the variation curves of the three chillers differ significantly, which is related to the design parameters and operating control strategies of each chiller. For chiller A, the relative energy efficiency is highest when the cooling water inlet temperature is 32℃ and the cooling load rate is 100% and 90%, respectively. When the load rate drops to 80%, the relative energy efficiency decreases significantly. When the cooling water inlet temperature is 24℃, the relative energy efficiency is highest in the cooling load rate range of 100% to 70%, and the relative energy efficiency decreases significantly when the cooling load rate is below this range. When the cooling water inlet temperature is 16℃, the relative energy efficiency is highest in the cooling load rate range of 90% to 40%, and the relative energy efficiency is lower in other load rates. As the cooling water inlet temperature decreases, the relative energy efficiency first increases and then decreases in the area close to 100% load rate. In the area with lower load rates, the relative energy efficiency increases as the cooling water temperature decreases. Therefore, as the cooling water inlet temperature decreases, the cooling load rate corresponding to the maximum relative energy efficiency of this type of chiller decreases. This indicates that when the cooling water temperature is high, the chiller should operate in a high load rate range; conversely, when the cooling water temperature is low, the chiller has higher relative energy efficiency in a low load rate range and lower relative energy efficiency at higher load rates. During chiller selection, it is crucial to consider the operating load rate range of the chiller in different cooling seasons, taking both cooling water temperature and the corresponding load rate range into account. For example, in district cooling systems with large total cooling loads and a large number of chillers, along with cold storage, it is evident that the base-load chillers may operate at low load rates during the cooling season due to higher cooling water temperatures, and at high load rates during the non-cooling season due to lower cooling water temperatures. For the same model, to operate at low load rates during the cooling season, a smaller capacity chiller needs to be designed to improve the relative energy efficiency of a single chiller; alternatively, during operation, complementary power from cold storage and release can be used to prevent the chiller from operating in a low load rate range.

[0184] For chiller B, at a cooling water temperature of 32℃, the optimal relative efficiency corresponds to a load range of 100% to 60%. As the cooling water temperature decreases, the relative efficiency of the chiller drops significantly at high load rates. At 100% load rate, the relative efficiency decreases by 4.7% from 32℃ to 24℃ and then by 9.1% from 24℃ to 16℃. At low load rates, the relative efficiency improves. At 30% load rate, the relative efficiency increases by 5.4% from 32℃ to 24℃ and then by 6.0% from 24℃ to 16℃. At a load rate 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 is at high load rates, making it unsuitable for low load rate operation. At low cooling water temperatures, the chiller's highest relative efficiency occurs around 60% load rate; operating above or below this load rate will lead to a decrease in relative efficiency. Therefore, when selecting chillers, it is necessary to consider high cooling water temperature conditions or cooling season conditions, and optimize the selection of the number and capacity of the main chillers to balance the cooling demand from users during the day and the lower cooling demand at night. Alternatively, during operation, the cooling load can be optimized by adjusting the number of chillers in operation to avoid operating them in inefficient areas. During the non-cooling season, when the cooling water temperature is low, it is also advisable to operate at around 60% load rate, and the selection of chillers and optimization of operating parameters should be based on this load rate.

[0185] For chiller C, within the 90-100% load range, the relative efficiency (REE) remains high for different cooling water temperatures. As the cooling load decreases, the REE improves significantly at lower cooling water temperatures, remaining above 70% within the 60-90% load range. At 70% load, the REE increases by 4.9% from 32℃ to 24℃ and by 2.1% from 24℃ to 16℃. For a cooling water temperature of 32℃, the REE is highest between 70-100% load; below 60% load, the REE decreases significantly with decreasing load. For cooling water temperatures of 24℃ and 16℃, the REE is higher than at 32℃. At 16℃, with a 45% load, the REE still reaches 70%. It can be seen that this model exhibits relatively good energy efficiency at lower cooling water temperatures, especially within the 60-70% load range. However, its energy efficiency drops rapidly below 40% load, and low-load operation should be avoided as much as possible. This needs to be considered comprehensively during design selection and operation.

[0186] At a cooling water temperature of 32℃, and above 70% load, both chillers B and C exhibit higher relative energy efficiency than chiller A. Below 60% load, chiller B shows a higher relative energy efficiency advantage. At a cooling water temperature of 24℃, and above 60% load, both chillers A and C show higher relative energy efficiency than chiller B. Below 40% load, chiller B shows a higher relative energy efficiency advantage. At a cooling water temperature of 16℃, and above 50% load, chillers A and C show higher relative energy efficiency advantages. At 40% load, chillers A and B show higher relative energy efficiency advantages. At 30% load, chiller B shows a higher relative energy efficiency advantage.

[0187] Comparisons between different models of refrigeration units cannot be generalized. This embodiment utilizes the proposed relative energy efficiency model to attempt to provide an analytical method for refrigeration unit performance selection and operation. Each refrigeration unit model has its own characteristics. When selecting a model, it is necessary to consider the hourly cooling load changes throughout the year, rationally allocate the number of refrigeration units and the capacity of each unit, and choose the most suitable refrigeration unit for the system. After the system is built and put into operation, it is necessary to fully utilize the advantages of each refrigeration unit based on its characteristics and load changes.

[0188] Figure 3 The table shows the maximum relative energy efficiency and corresponding cooling load rate of the three chillers at different cooling water temperatures, where loadmax is the cooling load rate corresponding to the maximum relative efficiency. It can be seen that chiller C has a high 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 chillers A and C is comparable; and in the cooling water temperature range of 30~32℃, the maximum energy efficiency of chillers B and C is comparable. Chiller A has a lower maximum relative energy efficiency at higher cooling water temperatures, such as 32℃; the maximum relative energy efficiency of chiller B decreases as the cooling water temperature decreases. The maximum relative energy efficiency at the same cooling water temperature reflects the chiller's highest operating performance. However, the corresponding chiller load rate must also be considered. Only when operating within the corresponding chiller load rate range at that cooling water temperature can the chiller's relative energy efficiency advantage be fully realized. Figure 3As can be seen, the maximum relative energy efficiency of chiller A corresponds to a large range of chiller load rates, varying from 60% to 90%. As the cooling water temperature changes, the chiller load rate corresponding to the maximum relative energy efficiency also decreases, indicating a high degree of precision in chiller operation and control. The chiller load rate range for chiller C is 70-80%, with a relatively narrow adjustment range. Chiller B falls between chillers A and C. Therefore, chiller A is suitable for smaller models, where it can leverage its high-efficiency chiller advantages at lower cooling water temperatures and lower load rates. Chiller C demonstrates a greater relative energy efficiency advantage within the 70-80% load rate range. Chiller B falls somewhere in between.

[0189] Figure 4 , Figure 5 and Figure 6 The graph shows the high-efficiency operating range (i.e., target operating range) for three chillers, A, B, and C. The orange line represents the lower limit of the cooling load rate within the high-efficiency operating range, and the blue line represents the upper limit. The high-efficiency operating range is defined as the load rate range exceeding 95% of the maximum relative energy efficiency of that model. The graph shows that the high-efficiency operating ranges for the three chillers are different. Figure 4 As can be seen, related to the refined regulation and control performance of chiller A, as the cooling water temperature decreases, the lower limit of its maximum efficient operating range continuously expands towards lower load rates, while the upper limit decreases to some extent. Based on this efficient operating range, the optimal operating range of the chiller load rate can be determined according to the actual cooling water temperature during actual operation, and the system parameters that meet the chiller's operating load rate can be determined at the system level. When selecting a model, it is necessary to consider its relatively low energy efficiency at higher load rates; during operation, it is necessary to leverage the advantages of this model at different cooling water temperatures and corresponding load rates. Figure 5 This is the high-efficiency operating range of refrigeration unit B. The high-efficiency operating range of refrigeration unit B is relatively wide, which is related to... Figure 3 The maximum relative energy efficiency curve of refrigeration unit B is relatively flat. Compared with refrigeration units A and C, the weakness of this model is its lower maximum relative energy efficiency, but it can cover a wider load rate range within the maximum relative energy efficiency operating range. Figure 6 This represents the high-efficiency operating range of chiller C. Compared to chillers A and B, its high-efficiency operating range has a narrower load rate range, but its maximum relative energy efficiency for each cooling water temperature is greater than that of chillers A and B.

[0190] This embodiment effectively selects chillers with high relative energy efficiency within a specific cooling water temperature and load rate range by determining the target operating range of the chiller. Because it considers the performance of the chiller under different preset conditions, the selection of the chiller is more accurate and reasonable. Furthermore, by introducing preset coefficients to determine the target threshold, the flexibility and applicability of the method are improved.

[0191] In some embodiments, the first variation curve represents the curve of relative energy efficiency changing with load rate at a preset cooling water temperature, and the second variation curve represents the curve of isentropic compression efficiency changing with load rate at a preset cooling water temperature.

[0192] Step S420 may include, but is not limited to, steps S421 to S422:

[0193] Step S421: Obtain the cooling water temperature range and load rate range under the application scenario of the chiller;

[0194] Step S422: Based on the cooling water temperature range and the load rate range, select the refrigerator with the highest isentropic compression efficiency corresponding to the second variation curve within the cooling water temperature range and the load rate range from multiple models, and use it as the target refrigerator.

[0195] In this embodiment, before determining the target chiller, it is first necessary to obtain the key parameters of the chiller's application scenario. The cooling water temperature range refers to the range of cooling water inlet temperatures that the chiller may encounter in actual applications, typically determined based on the climate characteristics of the application scenario and the cooling system design parameters. The cooling water temperature range that the chiller may encounter in actual operation can be determined based on local climate conditions, cooling tower performance, system design, and other factors. The load rate range refers to the range of load rates that the chiller may operate under in actual applications, typically determined based on the characteristics of the cooling load demand. The load rate range of the chiller in actual operation can be determined based on the cooling load demand of the building or process.

[0196] For any type of chiller, its target operating range must meet the requirement that the cooling water temperature range included in the target operating range of the chiller matches the cooling water temperature range of the application scenario; and for each temperature point within the cooling water temperature range of the application scenario, the target load rate range corresponding to the chiller matches the load rate range of the application scenario.

[0197] For refrigerators that meet the target operating range matching conditions, their isentropic compression efficiencies are further compared within the cooling water temperature range and load rate range of the application scenario. For each refrigerator, a second curve showing the isentropic compression efficiency as a function of load rate at a preset cooling water temperature is obtained. Within the cooling water temperature range and load rate range of the application scenario, the average isentropic compression efficiency of each refrigerator is calculated. By comparing the average isentropic compression efficiencies of each refrigerator model, the refrigerator with the highest efficiency is selected as the target refrigerator.

[0198] In one implementation of this embodiment, according to formulas (4) and (8), the isentropic compression efficiency of the compressor decouples the influence of the refrigerant thermodynamic cycle on the COP of the refrigeration unit, that is, it removes the ideal refrigeration... Coefficient of performance (COP) Compression work coefficient The influence of factors such as the total number of compression stages n of the compressor is considered separately, namely the relationship between isentropic compression efficiency and refrigerant flow rate, pressure ratio, inlet temperature, etc. Figure 7 , Figure 8 and Figure 9 The isentropic compression efficiencies of the compressors in three refrigeration units A, B, and C are given. Refrigeration unit A is a single-stage isentropic compressor with an efficiency of [missing value]. Refrigeration units B and C are two-stage isentropic compression efficiencies. .

[0199] Figure 7 Let be the single-stage isentropic compression efficiency of refrigerator A. Figure 7 The data shows that at cooling water temperatures of 20-32℃ and load rates of 90-100%, the compressor's isentropic compression efficiency is relatively close, exhibiting high efficiency between 88.0% and 91.7%. This indicates that the compressor operates efficiently at high load rates across most cooling water temperature ranges. As the load rate decreases, the isentropic compression efficiency drops sharply in the cooling water temperature range of 28-32℃, suggesting that the compressor should not operate at low load rates at high cooling water temperatures. At a cooling water temperature of 24℃ and a refrigeration unit load rate of 70-100%, the compressor's isentropic compression efficiency remains high. At a cooling water temperature of 20℃ and a refrigeration unit load rate of 60-100%, the compressor exhibits high isentropic compression efficiency. At a cooling water temperature of 16℃, the isentropic compression efficiency curve differs from other cooling water temperatures; the isentropic compression efficiency is lower at higher load rates, reaching its maximum at a load rate of 60%. At load rates of 60-30%, the isentropic compression efficiency of the compressor increases as the cooling water temperature decreases, indicating that the design and operation control of the compressor prioritizes operation at low cooling water temperatures and low load rates.

[0200] Figure 8 The curve shows the two-stage isentropic compression efficiency of refrigerator B. Figure 8The data shows that the efficiency curves for each isothermal cooling water temperature exhibit a parabolic shape. The highest point of each parabola shifts in the opposite direction to the lower load rate as the cooling water temperature decreases. In the higher load rate region, the isentropic compression efficiency increases with increasing cooling water temperature, while in the lower load rate region, the isentropic compression efficiency increases with decreasing cooling water temperature. At approximately 45% load rate, the five curves intersect at the same location. Overall, the isentropic compression efficiency curve of refrigerator B changes relatively smoothly, generally within the range of 70% to 86.3%. At cooling water temperatures of 28 and 32°C, there is a relatively high isentropic compression efficiency in the 70-100% load rate range; at a cooling water temperature of 24°C, there is a relatively high isentropic compression efficiency in the 60-80% load rate range; at cooling water temperatures of 20 and 16°C, the highest isentropic compression efficiency points appear at 70% and 60%, respectively.

[0201] Figure 9 The two-stage isentropic compression curves for refrigeration unit C show that, for a cooling water temperature range of 16–32°C, the isentropic compression efficiency is greater than 80% at load rates of 60–100%, indicating that the compressor can operate within its high-efficiency range at high load rates. Below 70% load rate, the isentropic compression efficiency increases with decreasing cooling water temperature. However, for each isentropic cooling water temperature curve, the isentropic compression efficiency decreases rapidly with decreasing load rate.

[0202] The isentropic compression efficiency curve of the compressor represents the design and operation control philosophy of the model. Comparing the three refrigeration unit models, refrigeration unit A has a higher single-stage isentropic compression efficiency, with some curves exceeding 90% isentropic compression efficiency. Refrigeration unit C's two-stage isentropic compression efficiency curves are close to 90% in some areas. The isentropic compression efficiency of refrigeration units A and C varies considerably, and in the lower isentropic compression efficiency range, it can be less than 60%. Relatively speaking, except near a cooling water temperature of 32℃, in most cooling water temperature ranges, the highest isentropic compression efficiency of refrigeration unit B is not as high as that of refrigeration units A and C, but its lowest isentropic compression efficiency is higher than that of refrigeration units A and C. The range of the isentropic compression efficiency curve of refrigeration unit B does not vary much. For refrigeration unit A, its single-stage isentropic compression efficiency is higher than that of refrigeration units B and C in two-stage isentropic compression efficiency. However, considering that the compression work coefficient of two-stage compression is greater than that of single-stage compression, the final relative efficiency is as follows: Figure 2 Both single-stage isentropic compression efficiency and two-stage isentropic compression efficiency represent the operating efficiency of the compressor itself. However, when comparing the operating performance of refrigeration machines, the contribution of the number of compression stages to the COP of the refrigeration machine must be considered.

[0203] from Figures 7-9As can be seen, using the refrigeration unit load rate and cooling water temperature to represent the isentropic compression efficiency of the compressor can reflect the operating performance of the refrigeration compressor to a certain extent, thus revealing certain compressor performance characteristics. Essentially, the compressor performance characteristics are expressed through the relationship between pressure ratio and flow rate, and are related to compressor speed, guide vane opening, diffuser opening, etc.

[0204] In one implementation of this embodiment, the relative energy efficiency and isentropic compression efficiency of the dual-condition refrigerator can also be analyzed, including a dual-condition fixed-frequency single-stage compressor refrigerator D and a dual-condition fixed-frequency two-stage compressor refrigerator E, with each refrigerator analyzed under two conditions: ice-making condition and air-conditioning condition.

[0205] Figure 10 The graph shows the relative energy efficiency of two chillers, D and E, under ice-making conditions at different cooling water temperatures. The relative energy efficiency of each chiller decreases with decreasing cooling water temperature, and also decreases with decreasing cooling load for each cooling water temperature. This indicates that the chillers were designed to prioritize the design ice-making conditions: a cooling water inlet temperature of 30℃, an ice-making temperature of -5.5 (-5.6)℃, and a 100% cooling load. Deviating from these design conditions results in a decrease in relative energy efficiency. At the design point, chiller E has a relatively higher relative energy efficiency. At a 100% cooling load and with a cooling water temperature greater than 20℃, chiller E has a higher relative energy efficiency than chiller D. With decreasing cooling load, the relative energy efficiency of chiller E drops rapidly, while the relative energy efficiency of chiller D changes relatively gradually. This shows that chiller E is suitable for operation near the design operating point or full load rate, and should not be reduced to produce ice at a lower refrigeration load rate, while chiller D can operate within a wider load rate range. During the design phase, chiller D or E should be selected based on the operating conditions. If chiller E is used, the system configuration design should, as far as possible, meet the conditions for chiller E to operate at full load rate. For example, the ice storage coil capacity must be precisely matched; if the capacity is too small, it may result in partial load rate operation during normal ice storage time. During operation, the conditions for chiller E to operate at full load rate should be created through system parameter adjustments. Simultaneously, when the return water glycol temperature reaches the design operating temperature of -1.8℃, it is not advisable to continue operating at a lower return water temperature for an extended period. If chiller D is selected, the selection of the ice storage coil capacity is more flexible during the design phase. During operation, the chiller can operate below the design return water glycol temperature, and its relative energy efficiency does not deviate significantly from the design operating condition.

[0206] Figure 11 The curves show the relative energy efficiency changes of the two refrigeration units under air conditioning operating conditions. Figure 10The relative energy efficiency of the refrigeration units decreases with decreasing load rate and decreasing cooling water temperature. Refrigeration unit E has a higher relative energy efficiency than refrigeration unit D at higher load rates, but a lower relative energy efficiency than refrigeration unit D at lower load rates. Figure 10 In comparison, the relative energy efficiency of both chillers in air conditioning mode is lower than that in ice-making mode. This indicates that both chillers were designed with ice-making performance as a priority. Figure 2 In comparison, the relative energy efficiency of dual-mode fixed-frequency chillers is significantly lower than that of base-load variable-frequency chillers. Therefore, when designing an ice storage system, the number and capacity configuration of both dual-mode and base-load chillers must be comprehensively considered. The base-load variable-frequency chillers must have sufficient capacity to reduce the time the dual-mode chillers operate in air conditioning mode. Simultaneously, when operating in air conditioning mode, dual-mode chillers should ideally run at full load to minimize inefficient low-load operation.

[0207] Figure 12 and Figure 13 The isentropic compression efficiency of a dual-condition, fixed-frequency, single-stage compression centrifugal chiller D is defined as follows: it is divided into ice-making and air-conditioning conditions. Figure 11 The relative efficiency trends are consistent: the isentropic compression efficiency decreases with decreasing load rate and decreasing cooling water temperature, and the slope of both trends gradually increases. Generally speaking, the isentropic compression efficiency is higher in icing operation than in air conditioning operation. In icing operation, the isentropic compression efficiency does not change significantly with cooling water temperature, while in air conditioning operation, the decrease is more pronounced. At higher cooling water temperatures, such as 30°C and a 100% cooling load rate, the isentropic compression efficiency is 84.1% for icing and 78.1% for air conditioning; at a 50% cooling load rate, the isentropic compression efficiency is 71.0% for icing and 64.7% for air conditioning. At lower cooling water temperatures, such as 20°C and a 100% cooling load rate, the isentropic compression efficiency is 77.2% for icing and 60% for air conditioning; at a 50% cooling load rate, the isentropic compression efficiency is 64.9% for icing and 46.0% for air conditioning. It can be seen that the compressor of this model is designed to meet the operating conditions of cooling water temperature of 30℃, cooling temperature of -5.6℃, and cooling load rate of 100%. Other operating conditions are all deviated from the design conditions, and the isentropic compression efficiency of the compressor has deviated and decreased to varying degrees. The deviation and decrease are greater in the air conditioning condition than in the ice making condition.

[0208] Figure 14 and Figure 15 This is the isentropic compression efficiency variation curve of the dual-condition, fixed-frequency, two-stage compression centrifugal refrigerator E. Figure 12 and Figure 13Like the single-stage compressor refrigeration unit D, the isentropic compression efficiency is highest under the design ice-making conditions of 30℃ cooling water temperature, -5.6℃ refrigeration temperature, and 100% load rate. Other operating conditions deviate from the design conditions, resulting in a decrease in isentropic compression efficiency. Under these design conditions, the compressor isentropic compression efficiency of refrigeration unit E is 80.0%. Figure 10 It can be seen 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 that the compression work coefficient and refrigeration coefficient also 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. Figure 10 As shown. Compared to refrigerator D, the isentropic compression efficiency of refrigerator E decreases rapidly with decreasing load rate, including all cooling water temperature ranges for both ice-making and air-conditioning operations. This indicates that for different cooling water temperature ranges, this refrigerator model should ideally operate at 100% load rate. This is consistent with... Figure 10 and Figure 11 The conclusions from the relative energy efficiency analysis are consistent. This also reflects the differences in the design and operation control philosophies of the two refrigeration unit models, requiring further analysis of compressor characteristics, including pressure ratio, flow rate, inlet temperature, inlet guide vanes, and diffuser opening adjustment.

[0209] This embodiment establishes a dual screening mechanism of operating range and efficiency curve to ensure that the selected model achieves optimal isentropic compression efficiency under target operating conditions, thereby maximizing the energy efficiency of the refrigeration system. This solves the problem in the prior art that it is impossible to accurately match high-efficiency refrigeration units according to the parameters of actual application scenarios, and avoids the efficiency loss caused by the deviation of operating parameters in the traditional selection process. It provides a quantitative decision basis for equipment matching under complex operating conditions.

[0210] This application, through proposing a normalized definition and mathematical model of the relative energy efficiency of refrigeration machines, effectively isolates the influence of external environmental parameters of the refrigerant system (such as cooling water temperature and refrigeration temperature) on the energy efficiency of the refrigeration machine. It establishes corresponding mathematical models and methods for obtaining the relative energy efficiency of different refrigeration machines, providing a unified benchmark for horizontal comparison of refrigeration machine performance under different operating conditions. For different models of refrigeration machines (including single-stage, two-stage, and three-stage compression, etc.) and different operating conditions (covering key parameters such as refrigeration temperature, cooling temperature, and refrigeration machine load rate), it conducts comprehensive performance analysis and comparison through relative energy efficiency indicators, overcoming the limitations of traditional absolute energy efficiency (COP) indicators, which are difficult to compare across operating conditions and models. Through relative energy efficiency change curves, it scientifically determines the performance of the refrigeration machine under different operating conditions. The high-efficiency operating range under different cooling water temperatures provides clear guidance for operation optimization. For multi-stage compression and multi-stage throttling cooling compressors, a method for obtaining the compressor's isentropic compression efficiency curve is proposed. By obtaining the compressor's isentropic compression efficiency curve, the changing trend of the compressor's isentropic compression efficiency under different cooling water temperatures, different refrigeration temperatures, and different load rates can be systematically analyzed, revealing in-depth the influencing factors of the compressor's core performance and providing data support for compressor design optimization and operation control. 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 improving the energy efficiency and economy of refrigeration systems. This represents a significant technological innovation in the design, application, and operation and maintenance of refrigeration equipment.

[0211] Please see Figure 16 This application also provides a refrigeration unit screening device 500, which can implement the above-described refrigeration unit screening method. The device includes:

[0212] The acquisition module 10 is used to acquire the actual energy efficiency and ideal energy efficiency of any model of refrigeration machine among a variety of models under various preset conditions, wherein the different preset conditions include different cooling water temperatures and / or load rates.

[0213] The first calculation module 20 is used to calculate the relative energy efficiency and isentropic compression efficiency of the refrigerator under each preset condition based on the actual energy efficiency and ideal energy efficiency of the refrigerator under each preset condition.

[0214] The second calculation module 30 is used to obtain a first variation curve of the relative energy efficiency and a second variation curve of the isentropic compression efficiency of the refrigerator based on the relative energy efficiency and isentropic compression efficiency of the refrigerator under each preset condition.

[0215] The screening module 40 is used to determine a target refrigerator based on a first variation curve of the relative energy efficiency of each type of refrigerator and a second variation curve of the isentropic compression efficiency, wherein the target refrigerator includes at least one type of refrigerator selected from the plurality of refrigerator types.

[0216] In some implementations, the acquisition module 10 may include:

[0217] The acquisition submodule is used to acquire the energy efficiency matrix of the chiller under the preset conditions. The energy efficiency matrix of the chiller represents the relationship between the actual energy efficiency of the chiller under the preset conditions and the cooling water temperature under the preset conditions, as well as the relationship between the actual energy efficiency of the chiller under the preset conditions and the load rate under the preset conditions.

[0218] The first calculation submodule is used to calculate 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. The cooling water operation mode is obtained through the energy efficiency matrix of the refrigerator.

[0219] The second calculation submodule is used to calculate 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 in the refrigerator.

[0220] In some implementations, the second computing submodule may include:

[0221] The first calculation unit is used to determine the specific cooling capacity and the specific work of isentropic compression under infinite-stage isentropic compression and infinite-stage throttling cooling based on 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.

[0222] The second calculation unit is used to take 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.

[0223] In some implementations, the first computing module 20 may include:

[0224] The third calculation submodule is used to take the ratio of the actual energy efficiency to the ideal energy efficiency of the refrigeration unit under the preset conditions as the relative energy efficiency of the refrigeration unit under the preset conditions.

[0225] The fourth calculation submodule is used to take the product of the refrigeration coefficient, compression work coefficient, inverter efficiency, AC motor efficiency and bearing efficiency of the refrigeration machine as the first coefficient. The refrigeration coefficient and the compression work coefficient are obtained based on the total number of compression stages of the compressor in the refrigeration machine, the saturation temperature of the evaporator and the saturation temperature of the condenser.

[0226] The fifth calculation submodule is used to take the ratio of the relative energy efficiency to the first coefficient as the isentropic compression efficiency.

[0227] In some implementations, the filtering module 40 may include:

[0228] The first determining submodule is used to determine the target operating range of any model of refrigeration machine among a variety of models of refrigeration machines, based on the first change curve of the relative energy efficiency of the refrigeration machine under each preset condition. The first change curve represents the curve of relative energy efficiency changing with load rate at a preset cooling water temperature, and the second change curve represents the curve of isentropic compression efficiency changing with load rate at a preset cooling water temperature.

[0229] The second determining submodule is used to determine the target refrigerator based on the target operating range of each model of refrigerator and the second variation curve of isentropic compression efficiency.

[0230] In some implementations, the first determining submodule may include:

[0231] The first acquisition unit is used to acquire the maximum value of the relative energy efficiency in the first variation curve under the preset conditions based on the cooling water temperature under the preset conditions.

[0232] The third calculation unit is used to multiply the maximum value of the relative energy efficiency by a preset coefficient to obtain the target threshold under the preset conditions;

[0233] The fourth calculation unit is used to take the range of load rates corresponding to relative energy efficiency greater than the target threshold as the target load rate range corresponding to the cooling water temperature under the preset conditions.

[0234] The fifth calculation unit is used to take the cooling water temperature under each preset condition and the target load rate range corresponding to each cooling water temperature as the target operating range of the chiller.

[0235] In some implementations, the second determining submodule may include:

[0236] The second acquisition unit is used to acquire the cooling water temperature range and load rate range under the application scenario of the chiller.

[0237] The selection unit is used to select, based on the cooling water temperature range and the load rate range, a refrigerator with the highest isentropic compression efficiency corresponding to the second variation curve within the cooling water temperature range and the load rate range from multiple models, as the target refrigerator.

[0238] The specific implementation method of the refrigeration machine screening device is basically the same as the specific implementation method of the refrigeration machine screening method described above, and will not be repeated here.

[0239] This application also provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the above-described refrigerator screening method. This electronic device can be any smart terminal, including tablet computers, in-vehicle computers, etc.

[0240] Please see Figure 17 , Figure 17 The hardware structure of an electronic device according to another embodiment is illustrated. The electronic device includes:

[0241] The processor 801 can be implemented using a general-purpose central processing unit (CPU), microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this application.

[0242] The memory 802 can be implemented as a read-only memory (ROM), static storage device, dynamic storage device, or random access memory (RAM). The memory 802 can store the operating system and other application programs. When the technical solutions provided in the embodiments of this specification are implemented through software or firmware, the relevant program code is stored in the memory 802 and is called and executed by the processor 801 using the refrigerator screening method of the embodiments of this application.

[0243] The 803 input / output interface is used to implement information input and output.

[0244] The communication interface 804 is used to enable communication and interaction between this device and other devices. Communication can be achieved through wired means (such as USB, Ethernet cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.).

[0245] Bus 805 transmits information between various components of the device (e.g., processor 801, memory 802, input / output interface 803, and communication interface 804);

[0246] The processor 801, memory 802, input / output interface 803, and communication interface 804 are connected to each other within the device via bus 805.

[0247] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described refrigerator screening method.

[0248] Memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, memory may optionally include memory remotely located relative to the processor, and these remote memories can be connected to the processor via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0249] The refrigerator screening method, refrigerator screening device, electronic device, and storage medium provided in this application obtain the actual and ideal energy efficiency of various refrigerator models under different cooling water temperatures and load rates. Obtaining the actual and ideal energy efficiency is to isolate the influence of external environmental parameters on the refrigerator performance. Based on the actual and ideal energy efficiency, the relative energy efficiency and isentropic compression efficiency under each condition are calculated. The relative energy efficiency reflects the actual efficiency level of the refrigerator relative to the ideal situation, while the isentropic compression efficiency quantifies the gas dynamic performance of the compressor. Based on the relative energy efficiency and isentropic compression efficiency, a first variation curve of relative energy efficiency and a second variation curve of isentropic compression efficiency are obtained. The first and second variation curves respectively show the trends of relative energy efficiency and isentropic compression efficiency with operating conditions, comprehensively reflecting the performance characteristics of the refrigerator under different conditions. Finally, the target refrigerator is determined based on the first and second variation curves of each refrigerator model. This application obtains the actual and ideal energy efficiency of a refrigerator under different preset conditions, calculates the relative energy efficiency and isentropic compression efficiency, generates variation curves, and determines the target refrigerator. It can effectively separate the influence of external environmental parameters and energy conversion efficiency loss, provide normalized indicators, facilitate the performance comparison of different refrigerator models, and provide a theoretical basis for selection through isentropic compression efficiency analysis, and accurately define the high-efficiency operating range.

[0250] The embodiments described in this application are for the purpose of more clearly illustrating 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. As those skilled in the art will know, with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems.

[0251] Those skilled in the art will understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of this application, and may include more or fewer steps than shown, or combine certain steps, or different steps.

[0252] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0253] Those skilled in the art will understand that all or some of the steps in the methods disclosed above, as well as the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, or suitable combinations thereof.

[0254] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0255] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0256] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of the units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0257] The units described above as separate components may or may not be physically separate. 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 the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0258] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0259] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes multiple instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing programs, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0260] The preferred embodiments of the present application have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present application. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and substance of the embodiments of the present application shall be within the scope of the claims of the present application.

Claims

1. A method of screening for a cryomachine, characterized in that, The method comprises: For any one of a plurality of types of chillers, obtaining actual energy efficiency and ideal energy efficiency of the chiller under a plurality of preset conditions, wherein the preset conditions are different in cooling water temperature and / or load rate; According to the actual energy efficiency and ideal energy efficiency of the chiller under each of the preset conditions, calculating relative energy efficiency and isentropic compression efficiency of the chiller under each of the preset conditions; According to the relative energy efficiency and isentropic compression efficiency of the chiller under each of the preset conditions, obtaining a first variation curve of the relative energy efficiency and a second variation curve of the isentropic compression efficiency of the chiller; According to the first variation curve of the relative energy efficiency and the second variation curve of the isentropic compression efficiency of the chiller of each type, determining a target chiller, the target chiller comprising at least one type of chiller selected from the plurality of types of chillers; The method comprises: For any one of a plurality of types of chillers, obtaining actual energy efficiency and ideal energy efficiency of the chiller under a plurality of preset conditions, wherein the preset conditions are different in cooling water temperature and / or load rate; For any one of a plurality of types of chillers, under each of the preset conditions, performing the following processing: Obtaining an energy efficiency matrix of the chiller under the preset conditions, the energy efficiency matrix of the chiller representing a relationship between the actual energy efficiency of the chiller under the preset conditions and the cooling water temperature in the preset conditions, and a relationship between the actual energy efficiency of the chiller under the preset conditions and the load rate in the preset conditions; According to the energy efficiency matrix of the chiller under the preset conditions, a heat transfer equation of a heat exchanger, and a cooling water operation mode, calculating a saturation temperature of a condenser in the chiller and a saturation temperature of an evaporator in the chiller, the cooling water operation mode being obtained through the energy efficiency matrix of the chiller; According to the saturation temperature of the condenser in the chiller and the saturation temperature of the evaporator in the chiller, calculating the ideal energy efficiency of the chiller under the preset conditions; The method comprises: According to the saturation temperature of the condenser in the chiller, the saturation temperature of the evaporator in the chiller, and thermodynamic parameters of refrigerant in the chiller, determining specific refrigeration capacity when infinitely stepped isentropic compression infinitely stepped throttling cooling and isentropic compression ratio when infinitely stepped isentropic compression infinitely stepped throttling cooling; 2. The method of claim 1, wherein, Taking a ratio of the specific refrigeration capacity and the isentropic compression ratio as the ideal energy efficiency of the chiller under the preset conditions. The method comprises: For each of the preset conditions, performing the following processing: Taking a ratio of the actual energy efficiency and the ideal energy efficiency of the chiller under the preset conditions as the relative energy efficiency of the chiller under the preset conditions; a product of a refrigeration coefficient, a compression work coefficient, a frequency converter efficiency, an alternating current motor efficiency, and a bearing efficiency of the refrigerating machine, the refrigeration coefficient and the compression work coefficient being obtained according to a total compression stage number of a compressor in the refrigerating machine, a saturation temperature of an evaporator, and a saturation temperature of a condenser; a ratio of the relative energy efficiency to the first coefficient is taken as the isentropic compression efficiency.

3. The method of claim 1, wherein, 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; the target refrigerating 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 the refrigerating machine of each type; for any type of refrigerating machine of the plurality of types, a target operation interval of the refrigerating machine is determined according to the first change curve of the relative energy efficiency of the refrigerating machine under each of the preset conditions; the target refrigerating machine is determined according to the target operation interval of the refrigerating machine of each type and the second change curve of the isentropic compression efficiency.

4. The method of claim 3, wherein, the target operation interval of the refrigerating machine represents the cooling water temperature of the refrigerating machine under each of the preset conditions and the target load rate interval corresponding to each of the cooling water temperatures when the relative energy efficiency is greater than a target threshold value; the target operation interval of the refrigerating machine of any type of refrigerating machine of the plurality of types is determined according to the first change curve of the relative energy efficiency of the refrigerating machine under each of the preset conditions, including: for any type of refrigerating machine of the plurality of types, the following processing is performed: for each of the preset conditions, the following processing is performed: a 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; the maximum value of the relative energy efficiency is multiplied by a preset coefficient to obtain the target threshold value under the preset condition; an interval of the load rate corresponding to the relative energy efficiency greater than the target threshold value is taken as the target load rate interval corresponding to the cooling water temperature under the preset condition; 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 operation interval of the refrigerating machine.

5. The method of claim 3, wherein, the target refrigerating machine is determined according to the target operation interval of the refrigerating machine of each type and the second change curve of the isentropic compression efficiency, including: a cooling water temperature range and a load rate range under a refrigerating machine application scenario are obtained; a refrigerating machine of which the target operation interval is within the cooling water temperature range and the load rate range and the isentropic compression efficiency corresponding to the second change curve is highest in the cooling water temperature range and the load rate range is selected from the plurality of types as the target refrigerating machine according to the cooling water temperature range and the load rate range.

6. A chiller screening device characterized by, the device includes: The acquisition module is configured to acquire actual energy efficiency and ideal energy efficiency of a chiller under a plurality of preset conditions for any one of a plurality of chiller models, wherein the plurality of preset conditions include different cooling water temperatures and / or different load rates; for any one of the plurality of chiller models, under each of the preset conditions, the following processes are performed: acquiring an energy efficiency matrix of the chiller under the preset condition, wherein the energy efficiency matrix of the chiller represents a relationship between the actual energy efficiency of the chiller under the preset condition and the cooling water temperature in the preset condition, and a relationship between the actual energy efficiency of the chiller under the preset condition and the load rate in the preset condition; calculating, according to the energy efficiency matrix of the chiller under the preset condition, a heat transfer equation of a heat exchanger, and a cooling water operation mode obtained from the energy efficiency matrix of the chiller, a saturation temperature of a condenser in the chiller and a saturation temperature of an evaporator in the chiller; calculating, according to the saturation temperature of the condenser in the chiller and the saturation temperature of the evaporator in the chiller, the ideal energy efficiency of the chiller under the preset condition; determining, according to the saturation temperature of the condenser in the chiller, the saturation temperature of the evaporator in the chiller, and thermodynamic parameters of refrigerant in the chiller, a specific refrigeration capacity when infinitely stepped isentropic compression and infinitely stepped throttling cooling and an isentropic compression specific work when infinitely stepped isentropic compression and infinitely stepped throttling cooling; and taking a ratio of the specific refrigeration capacity and the isentropic compression specific work as the ideal energy efficiency of the chiller under the preset condition; The first calculation module is configured to calculate, according to the actual energy efficiency and the ideal energy efficiency of the chiller under each of the preset conditions, a relative energy efficiency and an isentropic compression efficiency of the chiller under each of the preset conditions; The second calculation module is configured to obtain, according to the relative energy efficiency and the isentropic compression efficiency of the chiller 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 chiller; The screening module is configured to determine a target chiller according to the first change curve of the relative energy efficiency and the second change curve of the isentropic compression efficiency of the chiller of each model, wherein the target chiller includes at least one chiller model selected from the plurality of chiller models.

7. An electronic device, comprising: The electronic device includes a memory and a processor, the memory stores a computer program, and the processor implements the chiller screening method of any one of claims 1 to 5 when executing the computer program.

8. A computer-readable storage medium storing a computer program, the computer-readable storage medium comprising: The computer program is executed by the processor to implement the chiller screening method of any one of claims 1 to 5.

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