Compressor performance evaluation method and device, electronic equipment and storage medium

Abstract

The embodiment of the application provides a kind of compressor performance evaluation method, device, electronic equipment and storage medium, belong to refrigeration technical field.The method comprises: according to the compression process of compressor under multiple preset conditions, construct the thermodynamic cycle process of compressor under each preset condition;For each preset condition, based on the thermodynamic cycle process of compressor under the preset condition, construct the mathematical model of compressor under the preset condition, mathematical model includes multiple target performance parameters for evaluating the performance of compressor;The mathematical model of compressor under the preset condition is fitted with the thermophysical property parameter of the refrigerant of compressor, and the value of each target performance parameter of compressor under the preset condition is obtained;The value of multiple target performance parameters of compressor under each preset condition is compared and evaluated, and evaluation result is obtained.The embodiment of the application can quantitatively evaluate the performance of compressor.

Description

TECHNICAL FIELD

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

[0002] In the field of refrigeration engineering, large refrigerators usually use steam centrifugal compressors for refrigeration, including single-stage compression, two-stage compression, three-stage compression, and the like. The energy efficiency level of the refrigerator is mainly evaluated by the coefficient of performance (COP). This parameter is not only closely related to external system parameters such as the saturation temperature of the evaporator and the condenser, but also depends on internal core parameters of the refrigerator such as compressor efficiency. Among them, the compressor efficiency, as a key indicator for evaluating the rationality of the design and the performance of the operation of the refrigerator, is significantly related to factors such as the compressor characteristic curve, the inlet and outlet parameters, and the compressor control strategy.

[0003] However, when analyzing the performance using the COP of the refrigerator, since it is affected by the thermodynamic cycle efficiency determined by the chilled water and cooling water temperatures, the compression efficiency of the compressor cannot be directly judged by the COP value. The traditional compressor efficiency definition (such as single-stage isentropic compression efficiency, multi-variable compression efficiency, etc.) has obvious limitations in evaluating compressors of the multi-stage compression and multi-stage throttling cooling form, and cannot accurately reflect the actual working efficiency of such compressors. Therefore, when analyzing the design parameters and operating performance data of the refrigerator, there is a lack of tools that can effectively quantify the performance of the compressor, making it difficult to achieve quantitative evaluation of the performance of the compressor. SUMMARY

[0004] The main purpose of the embodiments of the present application is to propose a compressor performance evaluation method, device, electronic device, and storage medium, which can solve the problem of difficulty in quantitatively evaluating the performance of the compressor in the prior art.

[0005] To achieve the above-mentioned purpose, a first aspect of the embodiments of the present application proposes a compressor performance evaluation method, which comprises:

[0006] According to the compression process of the compressor under a plurality of preset conditions, a thermodynamic cycle flow process of the compressor under each of the preset conditions is constructed, at least one of the total number of compression stages and the refrigeration working condition included in different preset conditions is different, and the refrigeration working condition corresponds to an evaporation temperature and a condensation temperature;

[0007] For each of the preset conditions, a mathematical model of the compressor under the preset condition is constructed based on the thermodynamic cycle flow process of the compressor under the preset condition, and the mathematical model includes a plurality of target performance parameters for evaluating the performance of the compressor;

[0008] fitting the mathematical model of the compressor under the preset condition with thermophysical parameters of refrigerant of the compressor to obtain a value of each of the target performance parameters of the compressor under the preset condition;

[0009] performing performance comparison and evaluation on the values of the target performance parameters of the compressor under each of the preset conditions to obtain an evaluation result.

[0010] In some embodiments, the constructing a thermodynamic cycle process of the compressor under each of the preset conditions according to the compression process of the compressor under the preset conditions comprises:

[0011] for each of the preset conditions, decomposing the compression process into multiple isentropic compression stages according to the total compression stage number of the compressor under the preset condition, and introducing throttling cooling process between each isentropic compression stage to construct the thermodynamic cycle process.

[0012] In some embodiments, the constructing a mathematical model of the compressor under each of the preset conditions based on the thermodynamic cycle process of the compressor under the preset condition comprises:

[0013] for each of the preset conditions, obtaining multiple first performance parameters of the compressor under the preset condition, the first performance parameters being calculated according to existing performance parameters of the compressor;

[0014] constructing the mathematical model of the compressor under the preset condition based on the thermodynamic cycle process and the multiple first performance parameters.

[0015] In some embodiments, the thermophysical parameters include saturated pressure, saturated temperature, saturated liquid specific enthalpy, saturated gas specific enthalpy, superheated steam specific enthalpy and superheated steam specific entropy, the target performance parameters include multiple first performance parameters and multiple second performance parameters, the first performance parameters include ideal isentropic compression refrigeration energy efficiency, multi-stage compression power coefficient, multi-stage refrigeration capacity coefficient, isentropic compression efficiency and isentropic compression refrigeration energy efficiency, and the second performance parameters include discharge temperature, multi-stage isentropic compression specific work, multi-stage isentropic compression specific refrigeration capacity and compression inlet mass flow rate of each stage;

[0016] the fitting the mathematical model of the compressor under the preset condition with thermophysical parameters of refrigerant of the compressor to obtain a value of each of the target performance parameters of the compressor under the preset condition comprises:

[0017] for each of the preset conditions, performing the following processing:

[0018] fitting the saturated pressure, the saturated temperature, the saturated liquid specific enthalpy, the saturated vapor specific enthalpy, the superheated vapor specific enthalpy, the superheated vapor specific entropy, and the mathematical model, to obtain a value of the exhaust temperature, a value of the multi-stage isentropic compression specific work, a value of the multi-stage isentropic compression specific refrigeration, and a value of the compression intake quantity of each stage;

[0019] taking a difference between the saturated liquid specific enthalpy and the saturated vapor specific enthalpy as a value of an ideal specific refrigeration;

[0020] integrating a difference between the specific enthalpy of an evaporator pressure to a condenser pressure of the compressor to obtain a value of a specific isentropic compression work;

[0021] taking a ratio between the value of the ideal specific refrigeration and the value of the specific isentropic compression work as a value of an ideal isentropic compression refrigeration energy efficiency;

[0022] taking a ratio between the value of the multi-stage isentropic compression specific refrigeration and the value of the ideal specific refrigeration as a value of a multi-stage refrigeration coefficient;

[0023] taking a ratio between the value of the specific isentropic compression work and the value of the multi-stage isentropic compression specific work as a value of a multi-stage compression work coefficient;

[0024] taking a ratio between the value of the multi-stage isentropic compression specific work and an actual specific work as a value of an isentropic compression efficiency;

[0025] obtaining a value of an isentropic compression refrigeration energy efficiency according to a product of the value of the ideal isentropic compression refrigeration energy efficiency, the value of the multi-stage compression work coefficient, and a value of a multi-stage refrigeration coefficient.

[0026] In some embodiments, the performance comparison evaluation on the values of the plurality of target performance parameters of the compressor under each of the preset conditions obtains an evaluation result, including:

[0027] For each of the preset conditions, the values of the plurality of target performance parameters of the compressor under the preset condition are obtained;

[0028] The total compression stage number corresponding to each of the preset conditions and the value of each of the target performance parameters under a refrigeration working condition corresponding to each of the preset conditions are compared and evaluated to obtain the evaluation result, and the evaluation result indicates influences of the total compression stage number and the refrigeration working condition on each of the plurality of performance parameters.

[0029] In some embodiments, the performance comparison evaluation on the total compression stage number corresponding to each of the preset conditions and the value of each of the target performance parameters under the refrigeration working condition corresponding to each of the preset conditions to obtain the evaluation result includes:

[0030] The values ​​of exhaust temperature, multi-stage isentropic compression specific work, multi-stage isentropic compression specific cooling capacity, and each stage of compression intake volume are compared and evaluated to obtain a first evaluation result. The first evaluation result includes the changing trends of the exhaust temperature, specific work, specific cooling capacity, and each stage of compression intake volume as the total number of compression stages increases.

[0031] The values ​​of the ideal isentropic compression refrigeration efficiency, the multi-stage compression work coefficient, the multi-stage refrigeration capacity coefficient, and the isentropic compression refrigeration efficiency under each total number of compression stages and each refrigeration condition are compared and evaluated to obtain a second evaluation result. The second evaluation result includes the changing trends of the ideal isentropic compression refrigeration efficiency, the multi-stage compression work coefficient, the multi-stage refrigeration capacity coefficient, and the isentropic compression refrigeration efficiency as the total number of compression stages increases.

[0032] Based on the changing trends of the ideal isentropic compression refrigeration energy efficiency of the compressor under different refrigeration conditions, the changing trends of the multi-stage compression work coefficient, the changing trends of the multi-stage refrigeration capacity coefficient, and the changing trends of the isentropic compression refrigeration energy efficiency, a third evaluation result is obtained.

[0033] The evaluation result is obtained based on the first evaluation result, the second evaluation result, and the third evaluation result.

[0034] In some embodiments, after performing a performance comparison evaluation on the values ​​of multiple target performance parameters of the compressor under each of the preset conditions to obtain the evaluation result, the method further includes:

[0035] Obtain the value of the isentropic compression efficiency of the compressor under each of the preset conditions;

[0036] The total number of compression stages corresponding to each preset condition and the value of the isentropic compression efficiency under the refrigeration condition corresponding to each preset condition are compared and analyzed. The total number of compression stages and the refrigeration condition corresponding to the maximum value of the isentropic compression efficiency are taken as the target total number of compression stages and the target refrigeration condition of the compressor.

[0037] To achieve the above objectives, a second aspect of this application provides a compressor performance evaluation apparatus, the apparatus comprising:

[0038] The first construction module is used to construct the thermodynamic cycle flow of the compressor under each preset condition based on the compression process of the compressor under multiple preset conditions. The total number of compression stages and at least one of the refrigeration conditions are different under different preset conditions. The refrigeration condition corresponds to an evaporation temperature and a condensation temperature.

[0039] The second construction module is used to construct a mathematical model of the compressor under each preset condition based on the thermodynamic cycle flow of the compressor under the preset condition. The mathematical model includes multiple target performance parameters for evaluating the performance of the compressor.

[0040] The fitting module is used to fit the mathematical model of the compressor under the preset conditions with the thermophysical parameters of the refrigerant of the compressor to obtain the value of each target performance parameter of the compressor under the preset conditions.

[0041] The evaluation module is used to compare and evaluate the values ​​of multiple target performance parameters of the compressor under each preset condition, and obtain the evaluation results.

[0042] 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.

[0043] 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.

[0044] The compressor performance evaluation method, apparatus, electronic equipment, and storage medium proposed in this application construct a thermodynamic cycle flow based on the compressor's compression process under multiple preset conditions. These preset conditions differ in at least one of the total number of compression stages and refrigeration conditions, thus comprehensively considering the impact of different operating conditions and compression stages on compressor performance. For each preset condition, a mathematical model of the compressor is established based on the constructed thermodynamic cycle flow. This mathematical model includes multiple target performance parameters for evaluating compressor performance, comprehensively reflecting the compressor's performance characteristics under that condition. The mathematical model of the compressor under the preset conditions is fitted with the thermophysical parameters of the refrigerant to obtain specific values ​​for each target performance parameter. This combination of the theoretical model and actual operating conditions improves the accuracy of the evaluation results. Finally, the performance of the compressor under each preset condition is compared and evaluated to obtain the final evaluation result. By comparing and analyzing the performance parameters under different conditions, the compressor performance can be comprehensively evaluated, and the optimal operating conditions can be identified. This application, by constructing thermodynamic cycle flows and mathematical models under different preset conditions, and combining them with refrigerant thermophysical parameters to obtain target performance values ​​and conduct comparative evaluations, can accurately quantify compressor performance and eliminate external environmental interference. Attached Figure Description

[0045] Figure 1 This is a flowchart illustrating the compressor performance evaluation method provided in the embodiments of this application;

[0046] Figure 2 This is a schematic diagram of a multi-stage isentropic compression and multi-stage throttling cooling thermodynamic cycle provided in an embodiment of this application;

[0047] Figure 3 This is a schematic diagram of the multi-stage compression and multi-stage throttling isentropic compression process provided in the embodiments of this application;

[0048] Figure 4 This is a schematic diagram of the intake and exhaust states of each stage in the multi-stage isentropic compression and multi-stage throttling cooling process provided in the embodiments of this application;

[0049] Figure 5 This is a schematic diagram of the final stage exhaust temperature and evaporator evaporation ratio of the multi-stage isentropic compression and multi-stage throttling cooling provided in the embodiments of this application;

[0050] Figure 6 This is a schematic diagram illustrating the change in the intake volume ratio of each stage of multi-stage isentropic compression and multi-stage throttling cooling provided in the embodiments of this application;

[0051] Figure 7 This is a schematic diagram illustrating the changes in specific work and specific cooling capacity during multi-stage compression and multi-stage throttling cooling isentropic compression according to an embodiment of this application.

[0052] Figure 8 This is a schematic diagram of the multi-stage compression, multi-stage throttling cooling, isentropic compression COP provided in the embodiments of this application;

[0053] Figure 9 This is a schematic diagram of the multi-stage compression, multi-stage throttling, and cooling isentropic compression performance provided in the embodiments of this application;

[0054] Figure 10 This application provides an embodiment of the effect of different chilled water temperatures and cooling water temperatures on the COP of isentropic compression refrigeration. sn A schematic diagram;

[0055] Figure 11 This is a schematic diagram of the compressor performance evaluation device provided in the embodiments of this application;

[0056] Figure 12 This is a schematic diagram of the hardware structure of the electronic device provided in the embodiments of this application. Detailed Implementation

[0057] 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.

[0058] 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.

[0059] 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 the scope of this application.

[0060] In the field of refrigeration engineering, large-scale refrigeration machines typically rely on centrifugal compressors to achieve refrigeration cycles, with compression methods including single-stage, two-stage, and three-stage compression. The energy efficiency of a refrigeration machine is primarily evaluated using the coefficient of performance (COP). This parameter is closely related not only to external system parameters such as the saturation temperatures of the evaporator and condenser, but also to core internal parameters such as compressor efficiency. Compressor efficiency, as a key indicator for evaluating the design rationality and operational performance of a refrigeration machine, is significantly correlated with factors such as the compressor characteristic curve, intake and exhaust parameters, and control strategies.

[0061] However, existing technologies have many limitations in evaluating the performance of refrigeration machines and compressors:

[0062] When using COP to analyze the performance of a refrigeration unit, its compression efficiency cannot be directly determined by the COP value because it is significantly affected by the thermodynamic cycle efficiency determined by the chilled water temperature and cooling water temperature. It is also difficult to isolate the interference of external environmental factors on the compressor's performance.

[0063] Traditional compressor efficiency definitions (such as single-stage isentropic compression efficiency and polytropic compression efficiency) have significant limitations when evaluating compressors with multi-stage compression and multi-stage throttling cooling, and cannot accurately reflect the actual working efficiency of this type of compressor.

[0064] During the design and selection phase of refrigeration machines, there is a lack of clear theoretical basis to support the decision on whether to use single-stage, two-stage, or three-stage compression, which leads to a certain degree of blindness in the selection process.

[0065] When analyzing the design parameters and operating performance data of refrigeration units, there is a lack of tools that can effectively quantify compressor performance, making it difficult to achieve accurate evaluation and optimization of compressor performance.

[0066] Therefore, for centrifugal refrigeration compressors with multi-stage compression and multi-stage throttling cooling, there is an urgent need for a method that can eliminate the interference of external thermodynamic cycle factors, accurately define performance indicators, and establish an effective analysis model to meet the actual needs of refrigeration compressor design optimization, reasonable selection, and improved operating performance.

[0067] Based on this, embodiments of this application provide a compressor performance evaluation method, apparatus, electronic device, and storage medium, aiming to provide a performance evaluation method for a multi-stage compression and multi-stage throttling cooling centrifugal compressor, solving the problem of difficulty in quantitatively analyzing compressor performance parameters in the prior art. Embodiments of this application propose definitions for several relevant performance indicators and establish corresponding mathematical models; regression analysis yields mathematical expressions for the thermophysical properties of R134a refrigerant; based on the thermophysical properties of R134a and the mathematical model of centrifugal compression performance with multi-stage compression and multi-stage throttling cooling, the influence of the total number of compression stages on various performance parameters is analyzed, and the isentropic compression efficiency of single-stage and two-stage compression refrigeration machines is analyzed.

[0068] The compressor performance evaluation method, apparatus, electronic device, and storage medium provided in this application are specifically described through the following embodiments. First, the compressor performance evaluation method in this application is described.

[0069] The compressor performance evaluation method provided in this application relates to the field of refrigeration technology. This 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 compressor performance evaluation method, but is not limited to the above forms.

[0070] 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.

[0071] 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.

[0072] Figure 1 This is an optional flowchart of the compressor performance evaluation method provided in the embodiments of this application. Figure 1 The method may include, but is not limited to, steps S100 to S400.

[0073] Step S100: Based on the compression process of the compressor under multiple preset conditions, construct the thermodynamic cycle flow of the compressor under each preset condition. The total number of compression stages and at least one of the refrigeration conditions are different under different preset conditions. The refrigeration condition corresponds to an evaporation temperature and a condensation temperature.

[0074] In this embodiment, taking R134a refrigerant as an example, the performance of compressors with different compression stages is analyzed. First, based on the compression process of the compressor under multiple preset conditions, a thermodynamic cycle flow is constructed for each preset condition; wherein, the difference in the preset conditions is reflected in at least one of the total number of compression stages or the refrigeration condition, and the refrigeration condition is determined by a set of evaporation and condensation temperatures. The total number of compression stages represents the number of stages in the compression process, and the refrigeration condition is defined by the combination of evaporation and condensation temperatures, which can be specifically achieved by setting different temperature parameters and the number of compression stages.

[0075] In this embodiment, the thermodynamic cycle is a multi-stage isentropic compression and multi-stage throttling cooling thermodynamic cycle, including multiple isentropic compression processes and throttling cooling processes between adjacent compression processes. Specifically, multi-stage isentropic compression refers to dividing the compression process into multiple stages (such as single-stage, two-stage, three-stage, etc.), with each stage performing isentropic compression (i.e., ideal reversible adiabatic compression). After each stage of compression, the gas pressure and temperature increase, but through subsequent cooling processes, the gas temperature entering the next stage is reduced, thereby reducing the compression work of the next stage. Multi-stage throttling cooling refers to the throttling of part of the refrigerant between each compression stage through a throttling device (such as an expansion valve), generating low-temperature, low-pressure vapor. This vapor mixes with the high-temperature gas after the previous stage compression, utilizing its cooling capacity to achieve intermediate cooling, thereby reducing the inlet temperature of the next stage compression. The entire cycle includes multiple compression processes, multiple cooling processes, and multiple throttling processes, ultimately completing the refrigerant evaporation, compression, condensation, and throttling processes.

[0076] Step S200: For each of the preset conditions, based on the thermodynamic cycle flow of the compressor under the preset conditions, construct a mathematical model of the compressor under the preset conditions, the mathematical model including multiple target performance parameters for evaluating the performance of the compressor.

[0077] In this embodiment, for each preset condition, a mathematical model containing multiple target performance parameters is constructed based on its thermodynamic cycle flow. The mathematical model refers to a mathematical expression established based on the thermodynamic cycle flow, containing multiple target performance parameters. Specifically, it is achieved by integrating the existing performance parameters of the compressor and thermodynamic relationships. This feature is used to quantify the key performance indicators of the compressor. The mathematical model may include target performance parameters such as: multi-stage compression work coefficient, multi-stage cooling capacity coefficient, isentropic compression efficiency (isentropic compression efficiency of a multi-stage compression and multi-stage throttling cooling compressor), ideal isentropic compression cooling efficiency (ideal isentropic compression cooling efficiency of an infinite-stage isentropic compression and infinite-stage throttling cooling system), and isentropic compression cooling efficiency (cooling efficiency of a multi-stage isentropic compression and multi-stage throttling cooling thermodynamic cycle).

[0078] Step S300: Fit the mathematical model of the compressor under the preset conditions with the thermophysical parameters of the refrigerant of the compressor to obtain the value of each target performance parameter of the compressor under the preset conditions.

[0079] In this embodiment, the mathematical model is fitted with the thermophysical parameters of the refrigerant used in the compressor to calculate the specific values ​​of each target performance parameter under each preset condition. The thermophysical parameters refer to the state parameters of the refrigerant in a thermodynamic cycle, and may include the relationship between the refrigerant's saturation temperature, saturation pressure, saturated liquid specific enthalpy, saturated gaseous specific enthalpy, and superheated vapor specific entropy and temperature and pressure. These parameters can be obtained through experimental measurements or a property database, and are used to combine the mathematical model with the actual refrigerant characteristics to ensure the physical accuracy of the calculation results. Fitting refers to the process of correlating the mathematical model with the refrigerant's thermophysical parameters, which can be achieved through numerical analysis or iterative algorithms to solve for the actual values ​​of the target performance parameters, such as exhaust temperature and compression work. Based on the above thermophysical parameters and the formulas in the mathematical model, the specific values ​​of target performance parameters such as specific work, specific cooling capacity, compression work coefficient, and cooling capacity coefficient at each stage can be calculated.

[0080] Step S400: The performance of the compressor under each of the preset conditions is compared and evaluated to obtain the evaluation result.

[0081] In this embodiment, the performance of the compressor is compared and evaluated under each preset condition for multiple target performance parameters, and the evaluation results are obtained. The evaluation results can be used to analyze the performance of the compressor under different compression stages and refrigeration conditions, providing a basis for the design, selection, and operation optimization of the compressor.

[0082] Specifically, the evaluation results may include: analyzing the trends in exhaust temperature, specific work, and COP under different numbers of stages (such as single-stage, two-stage, and five-stage) to obtain the impact of the total number of compression stages on performance (for example, as the number of stages increases, the specific work gradually decreases, and five-stage compression approaches the optimization limit of infinite compression); comparing the changes in isentropic compression efficiency under different evaporation / condensation temperatures (such as ice storage cooling conditions: -6.6℃ / 35℃; air conditioning conditions: 6℃ / 38℃) to obtain the impact of refrigeration conditions on performance; and based on isentropic compression efficiency, excluding external circulation factors, directly comparing the actual operating efficiency of compressors under different numbers of stages or different operating conditions to achieve a horizontal comparison of compressor efficiency.

[0083] This embodiment effectively isolates the influence of external operating conditions and accurately evaluates the compressor's performance by constructing thermodynamic cycle models under multiple preset conditions and fitting refrigerant property parameters. Comparative analysis of multiple target performance parameters comprehensively reflects the compressor's performance characteristics, providing a theoretical basis for compressor design optimization and selection.

[0084] In some embodiments, step S100 may include, but is not limited to, step S110:

[0085] Step S110: For each of the preset conditions, the compression process is decomposed into multiple isentropic compression stages according to the total number of compression stages of the compressor under the preset conditions, and a throttling cooling process is introduced between each isentropic compression stage to construct the thermodynamic cycle process.

[0086] In this embodiment, for each preset condition, based on the total number of compression stages n of the compressor under the preset condition (n is a positive integer, and can take values ​​of 1, 2, 3, ..., 5, etc.), the entire compression process is decomposed into n consecutive isentropic compression stages, and a throttling cooling process is introduced between two adjacent isentropic compression stages. Through the orderly combination of the above isentropic compression stages and throttling cooling processes, a complete multi-stage isentropic compression and multi-stage throttling cooling thermodynamic cycle is constructed.

[0087] Specifically, the multi-stage isentropic compression and multi-stage throttling cooling thermodynamic cycle is used to accurately describe the energy conversion and state change laws of refrigerant under the coupled effects of "multi-stage compression" and "multi-stage throttling cooling". Its core is to decompose the compression process into multiple isentropic compression stages and introduce throttling cooling between adjacent stages, achieving precise control and quantitative analysis of energy loss. The thermodynamic cycle consists of two key processes, "multi-stage isentropic compression" and "multi-stage throttling cooling," alternating to form a complete thermodynamic closed loop. Isentropic compression is a reversible compression process. For a multi-stage compression and multi-stage throttling cooling system, it includes multiple isentropic compression processes. Between adjacent isentropic compression processes, there is a cooling process. The refrigerant vapor generated by the multi-stage throttling process mixes with the exhaust gas from the previous isentropic compression process, achieving cooling of the compressor exhaust gas.

[0088] like Figure 2 As shown, Figure 2 This represents a multi-stage compression and multi-stage throttling cooling thermodynamic cycle. Multi-stage isentropic compression is the overall compression process that moves the refrigerant from the low pressure of the evaporator to the high pressure of the condenser. It can be broken down into n consecutive isentropic compression stages (reversible compression with no energy loss). Each compression stage (the i-th stage) moves the refrigerant from the intake pressure... Compress to exhaust pressure During the process, the specific entropy remains unchanged, but the temperature and pressure increase. Multi-stage throttling cooling introduces a throttling process between two adjacent compression stages (between the exhaust of stage i and the intake of stage i+1). Part of the refrigerant is depressurized and evaporated into low-temperature vapor through a throttling valve, which mixes with the high-temperature exhaust of stage i, reducing the intake temperature of stage i+1 and achieving "interstage cooling". This process controls the cooling effect through energy balance (such as the conservation of total energy before and after mixing), reducing the energy consumption of the next compression stage.

[0089] likeFigure 3 As shown, Figure 2 The compression process is magnified locally. Point (i) to (i)s in the figure represents the i-th stage isentropic compression process, and point (i+1) represents the state after the i-th stage compressed exhaust gas is mixed with the (i+1)th throttling steam.

[0090] In one embodiment of this example, for multi-stage compression, the ideal pressure ratio of each stage can be expressed as formula (1):

[0091] (1);

[0092] In formula (1), n ​​is the total number of compression levels; The pressure is the condenser pressure, in kPa. Evaporator pressure, kPa; and , respectively, are the intake and exhaust pressures of the i-th stage compression, in kPa.

[0093] For the (i+1)th throttling stage, its energy balance equation is expressed as formula (2):

[0094] (2);

[0095] In formula (2), The intake air volume for the i-th stage compression is expressed in kg / s. The compression intake volume for stage i+1 is kg / s; , Here, represents the saturated liquid specific enthalpy and saturated gas specific enthalpy of the refrigerant corresponding to the i-th stage intake pressure, respectively, in kJ / kg; Let be the saturated liquid specific enthalpy of the refrigerant corresponding to the i-th stage exhaust pressure, in kJ / kg. Formula (2) can also be expressed as formula (3):

[0096] (3);

[0097] Formula (3) represents the ratio of intake volume between two adjacent compression stages.

[0098] For the throttling process, the throttling evaporation ratio is expressed by formula (4):

[0099] (4);

[0100] In formula (4), This represents the mass ratio of refrigerant phase change to steam after the (i+1)th stage throttling process.

[0101] For the cooling process between two compression stages, the energy balance is expressed by formula (5):

[0102] (5);

[0103] In formula (5), Specific heat, kJ / kg·℃; This represents the intake temperature of the (i+1)th stage compression, which is the temperature of the exhaust gas from the (i)th stage compression and the mixture of the (i+1)th stage throttling gas. Let represent the saturation temperature corresponding to the exhaust pressure of the i-th stage compression, or the saturation temperature corresponding to the intake pressure of the (i+1)-th stage compression, in °C. Formula (5) can also be expressed as formula (6):

[0104] (6);

[0105] In formulas (2) to (6), the refrigerant saturation state parameters can be expressed as formulas (7) to (9):

[0106] (7);

[0107] (8);

[0108] (9);

[0109] In formula (7), This represents the saturation temperature corresponding to the intake pressure of the i-th stage compression. The refrigerant saturation state parameters are single-valued functions and can all be determined by the saturation temperature or saturation pressure.

[0110] For each stage of the isentropic compression process, it can be expressed as formula (10):

[0111] (10);

[0112] In formula (10), , Let represent the specific entropy of the inlet and outlet gases of the i-th stage of isentropic compression, respectively, in kJ / kg·℃. Both specific entropies are functions of pressure and temperature, as shown in equations (11) and (12):

[0113] (11);

[0114] (12);

[0115] In the known , , Under these conditions, based on the relationship between specific entropy and pressure and temperature, the exhaust temperature of the i-th stage of isentropic compression can be obtained. .

[0116] This embodiment decomposes the compression process into multiple isentropic compression stages and introduces a throttling cooling process, thus more accurately simulating the actual working process of a multi-stage compression, multi-stage throttling cooling compressor. This construction method can reflect the thermodynamic state changes between the stages inside the compressor, providing a more reasonable theoretical basis for subsequent mathematical modeling and performance evaluation. Therefore, it is possible to more accurately evaluate the compressor's performance under different preset conditions, providing strong support for compressor design optimization and selection decisions.

[0117] In some embodiments, step S200 may include, but is not limited to, steps S210 to S220:

[0118] Step S210: For each of the preset conditions, obtain multiple first performance parameters of the compressor under the preset conditions, wherein the first performance parameters are calculated based on the existing performance parameters of the compressor;

[0119] Step S220: Construct the mathematical model of the compressor under the preset conditions based on the thermodynamic cycle process and multiple first performance parameters.

[0120] In this embodiment, for each preset condition, the existing performance parameters of the compressor are first determined. These parameters include, but are not limited to: basic thermodynamic parameters (including evaporator saturation temperature, condenser saturation temperature, evaporator pressure, condenser pressure, etc.); refrigerant characteristic parameters (including saturated liquid specific enthalpy, saturated gas specific enthalpy, superheated vapor specific enthalpy, superheated vapor specific entropy, etc.); and cycle process parameters (including intake air volume of each compression stage, throttling evaporation ratio, isentropic compression exhaust temperature, etc.). Based on the above existing performance parameters, the first performance parameter is derived and calculated through thermodynamic formulas. The first performance parameter is the core parameter characterizing the cycle characteristics and compressor performance. Then, using a multi-stage isentropic compression and multi-stage throttling cooling thermodynamic cycle as a framework, the first performance parameter is correlated through equations to form a complete mathematical model.

[0121] Specifically, the first performance parameters include ideal isentropic compression refrigeration efficiency, multi-stage compression work coefficient, multi-stage refrigeration capacity coefficient, isentropic compression efficiency, and isentropic compression refrigeration efficiency. Among these, ideal isentropic compression refrigeration efficiency... The ideal isentropic compression refrigeration efficiency (CFE) refers to the ideal refrigeration coefficient of an infinite-stage compression and infinite-stage throttling cooling thermodynamic cycle, representing the theoretical limit of refrigeration cycle energy efficiency. When the number of compression stages approaches infinity, the pressure ratio of each stage approaches 1, the throttling cooling process becomes infinitely subdivided, and the cycle approaches reversibility. At this point, the refrigeration efficiency is determined solely by the saturation temperatures of the evaporator and condenser (independent of the number of compressor stages and actual operating efficiency), representing the highest energy efficiency level achievable by this thermodynamic cycle (determined by the evaporation and condensation temperatures). The ideal isentropic compression refrigeration efficiency serves as a "benchmark upper limit" for evaluating actual cycle performance, measuring the difference between a real multi-stage system and the ideal state. Multi-stage compression work coefficient. This refers to the ratio of the isentropic compression work of n-stage compression to the isentropic compression work of an infinite number of stages. It can be used to quantify how close the compression work is to the ideal minimum under actual compression stages. The closer the coefficient is to 1, the closer the total compression work of n-stage compression is to the theoretical minimum work of an infinite number of stages, and the smaller the energy loss during compression. It directly reflects the contribution of the number of compression stages to energy consumption reduction and guides stage design (e.g., if the document shows that this coefficient is already close to 1 after two-stage compression, further increases in the number of stages will have limited improvement). Multistage cooling capacity coefficient. This refers to the ratio of the specific cooling capacity of n-stage compression to the specific cooling capacity of infinite-stage compression. It can be used to quantify how close the actual cooling capacity is to the ideal maximum value under a given number of compression stages. The closer the coefficient is to 1, the closer the actual cooling capacity of n-stage compression is to the theoretical maximum cooling capacity of infinite stages. The coefficient changes very little (e.g., only a slight increase of 1.4% from single-stage to 5-stage), indicating that the number of stages has a limited impact on cooling capacity, clarifying that the core value of multi-stage compression is "reducing energy consumption" rather than "increasing cooling capacity." Isentropic compression efficiency. This refers to the efficiency of the compressor during the actual compression process. It eliminates interference from external factors such as chilled water / cooling water temperature (thermodynamic cycle) and auxiliary equipment efficiency, reflecting only the energy conversion efficiency of the compressor's own compression process (i.e., the ratio of actual compression work to theoretical isentropic compression work). It enables horizontal comparisons of compressor performance under different stages and operating conditions (such as comparing the efficiency of single-stage and two-stage compression under the same load), and is a core indicator for evaluating the quality of compressor design. Isentropic compression refrigeration energy efficiency. The coefficient of performance (COP) refers to the theoretical COP of an n-stage compression multi-stage throttling cooling cycle. It comprehensively reflects the inherent energy efficiency of an n-stage compression cycle and is determined by the ideal isentropic compression refrigeration efficiency, the multi-stage refrigeration capacity coefficient, and the multi-stage compression work coefficient. It is independent of the actual operating efficiency of the compressor (related only to the number of stages and thermodynamic cycle parameters). It can serve as an intermediate parameter for calculating isentropic compression efficiency, bridging the gap between actual COP and theoretical cycle energy efficiency, and quantifying the impact of the number of stages on the cycle's inherent energy efficiency.

[0122] In one embodiment of this example, the COP of the refrigeration unit can be expressed as formula (13):

[0123] (13);

[0124] In formula (13), The specific refrigeration capacity is the cooling capacity per unit mass of refrigerant in the evaporator, expressed in kJ / kg. The total input electrical work per unit mass of refrigerant, i.e., specific work, is expressed in kJ / kg. Here, the unit mass of refrigerant refers to the intake air volume of the final stage compressor.

[0125] For n-stage compression refrigeration, its cooling capacity is the specific cooling capacity of the evaporator before the first stage compression. Here, the refrigerant quality is still based on the intake air volume of the final compression stage, which can be expressed as formula (14):

[0126] (14);

[0127] Formula (13) can also be expressed as formula (15):

[0128] (15);

[0129] Or it can be expressed as formula (16):

[0130] (16);

[0131] Among them, the ideal isentropic compression refrigeration efficiency, multi-stage compression work coefficient, multi-stage refrigeration capacity coefficient and isentropic compression efficiency are defined by formulas (17) to (20):

[0132] (17);

[0133] (18);

[0134] (19);

[0135] (20);

[0136] In formula (17) ~ formula (20), Ideal isentropic compression refrigeration efficiency for infinite-level isentropic compression and infinite-level throttling cooling; and These are the ideal specific cooling capacity and specific isentropic compression work of a multi-stage isentropic compression and multi-stage throttling cooling cycle, respectively, in kJ / kg; The specific work of multi-stage isentropic compression is expressed in kJ / kg. The actual specific work of multi-stage compression is expressed in kJ / kg. The coefficient of performance (COP) for a multi-stage compression and multi-stage throttling cooling cycle; The compression work coefficient for a multi-stage compression and multi-stage throttling cooling cycle; The isentropic compression efficiency of a compressor with a multi-stage compression and multi-stage throttling cooling cycle.

[0137] Meanwhile, the power input from the electrical power input to the compressor shaft power output can be expressed as formula (21):

[0138] (twenty one);

[0139] In formula (21), , , These are the efficiencies of frequency converters, motors, and mechanical transmission equipment, respectively.

[0140] Define multi-stage isentropic compression cooling energy efficiency For formula (22):

[0141] (twenty two);

[0142] In formula (22), The isentropic compression refrigeration efficiency of a refrigerator with an n-stage compression, n-stage throttling, and n-1-stage cooling cycle. As n→∞, →1 and →1, therefore we have → .

[0143] In formula (16), The refrigeration efficiency of an ideal isentropic compression system, characterized by infinite-stage isentropic compression and infinite-stage throttling cooling, is independent of the total number of compressor stages and depends only on the saturation temperatures of the evaporator and condenser; the coefficient of performance (COP) is... Depends on the evaporator specific cooling capacity It is related to the number of compressor stages; compression work coefficient It is also related to the number of compressor stages; It depends on the number of compressor stages and the thermodynamic cycle characteristics determined by the saturation temperatures of the evaporator and condenser, and is independent of the actual operating conditions of the compressor.

[0144] According to formula (22), the multi-stage isentropic compression efficiency of the compressor can be expressed as formula (23):

[0145] (twenty three);

[0146] According to the definition in formula (20), the isentropic compression efficiency of the compressor It depends on the actual compression ratio of the compressor and the isentropic compression ratio of multi-stage compression. In another form, formula (23) shows that the isentropic compression efficiency of the compressor can be obtained by parameters such as the actual COP of the refrigeration machine, the saturation temperature of the evaporator and condenser, the total number of compression stages of the compressor, as well as the efficiency of the frequency converter, the efficiency of the motor, and the efficiency of the mechanical transmission.

[0147] The COP of the refrigeration machine expressed in formula (16) can be divided into three influencing factors. One is the refrigeration system parameters, including the refrigeration temperature and the cooling temperature, which mainly affect the ideal isentropic compression cycle. One is an inherent performance parameter of the thermodynamic cycle; the other is related to the total number of compression stages in the compressor, mainly affecting the coefficient of performance (COP). With compression work coefficient The third type is related to the actual compression work, i.e., the compressor's isentropic compression efficiency. This parameter reflects the actual operating efficiency and performance of the compressor. It can be used for horizontal comparisons under different refrigeration conditions and with different total number of compressor stages, and can be used for design and operation analysis.

[0148] The work done by multi-level isentropic compression can be expressed as formula (24):

[0149] (twenty four);

[0150] In formula (24), The isentropic compression specific work of stage n compression, in kJ / kg; Let be the work done by the i-th level isentropic compression, in kJ / kg. As n→∞, → Formula (24) can also be expressed as formula (25):

[0151] (25);

[0152] In formula (24), The amount of refrigerant condensed in the condenser, expressed in kg, is given by formula (26):

[0153] (26);

[0154] For multi-stage compression ratio refrigeration capacity, it can be expressed as formula (27):

[0155] (27);

[0156] Or it can be expressed as formula (28):

[0157] (28);

[0158] As n→∞, → .

[0159] Given the saturation temperature of the evaporator and the saturation temperature of the condenser (or the saturation pressure of the evaporator and the saturation pressure of the condenser), and the total number of compression stages n of the compressor, according to formulas (1), (4), (6) to (12), and (16) to (22). , , , , By considering process variables, the relevant performance coefficients of the refrigeration machine and compressor can be obtained. , , , And so on, and based on the actual COP of the refrigeration unit, as well as parameters such as inverter efficiency, motor efficiency, and mechanical transmission efficiency, the isentropic compression efficiency of the compressor is obtained by formula (23). This embodiment uses R134a refrigerant for analysis. It can be combined with thermophysical property equations such as formulas (7) to (9) and formula (11), and the isentropic compression exhaust temperature can be solved according to formulas (10) to (12).

[0160] This embodiment constructs a mathematical model that can fully describe the thermodynamic behavior of the compressor under specific preset conditions, and quantitatively evaluates its performance through a first performance parameter, laying the foundation for subsequent parameter fitting and comparative analysis. Its core lies in transforming the physical description of the cyclic process into a calculable mathematical relationship, and all parameters are derived from existing performance parameters, ensuring the objectivity and verifiability of the model.

[0161] In some embodiments, the thermophysical parameters include saturation pressure, saturation temperature, saturated liquid specific enthalpy, saturated gas specific enthalpy, superheated vapor specific enthalpy, and superheated vapor specific entropy. The plurality of target performance parameters include a plurality of first performance parameters and a plurality of second performance parameters. The plurality of first performance parameters include ideal isentropic compression refrigeration efficiency, multi-stage compression work coefficient, multi-stage refrigeration capacity coefficient, isentropic compression efficiency, and isentropic compression refrigeration efficiency. The plurality of second performance parameters include exhaust temperature, multi-stage isentropic compression specific work, multi-stage isentropic compression specific refrigeration capacity, and intake air volume of each compression stage.

[0162] Step S300 may include, but is not limited to, steps S310 to S380:

[0163] For each of the preset conditions, the following processing is performed:

[0164] Step S310: Fit the saturation pressure, saturation temperature, saturated liquid specific enthalpy, saturated gas specific enthalpy, superheated steam specific enthalpy, superheated steam specific entropy, and the mathematical model to obtain the values ​​of the exhaust temperature, the multi-stage isentropic compression specific work, the multi-stage isentropic compression specific cooling capacity, and the intake air volume of each compression stage.

[0165] Step S320: The difference between the saturated liquid specific enthalpy and the saturated gas specific enthalpy is taken as the value of the ideal specific refrigeration capacity;

[0166] Step S330: The integral of the specific enthalpy difference between the evaporator pressure and the condenser pressure of the compressor is used as the value of the specific isentropic compression work.

[0167] Step S340: The ratio of the ideal specific cooling capacity to the specific isentropic compression work is taken as the value of the ideal isentropic compression refrigeration energy efficiency.

[0168] Step S350: The ratio of the value of the multi-stage isentropic compression ratio refrigeration capacity to the value of the ideal ratio refrigeration capacity is used as the value of the multi-stage refrigeration capacity coefficient;

[0169] Step S360: The ratio of the value of the isentropic compression work to the value of the multi-stage isentropic compression work is taken as the value of the multi-stage compression work coefficient;

[0170] Step S370: The ratio of the value of the multi-stage isentropic compression specific work to the actual specific work is taken as the value of the isentropic compression efficiency.

[0171] Step S380: The value of the isentropic compression refrigeration efficiency is obtained by multiplying the value of the ideal isentropic compression refrigeration efficiency, the value of the multi-stage compression work coefficient, and the value of the multi-stage refrigeration capacity coefficient.

[0172] In this embodiment, by fitting the mathematical model of the compressor under preset conditions and the thermophysical parameters of the refrigerant, specific values ​​of multiple target performance parameters are obtained. These parameters include secondary performance parameters such as exhaust temperature, specific work, specific cooling capacity, and intake air volume of each compression stage, as well as primary performance parameters such as ideal isentropic compression refrigeration efficiency, multi-stage compression work coefficient, multi-stage cooling capacity coefficient, isentropic compression efficiency, and isentropic compression refrigeration efficiency.

[0173] Specifically, saturated pressure refers to the pressure of the refrigerant when it is in gas-liquid two-phase equilibrium at a given temperature; saturated temperature refers to the temperature of the refrigerant when it is in gas-liquid two-phase equilibrium at a given pressure; saturated liquid specific enthalpy refers to the enthalpy value of a unit mass of saturated liquid refrigerant; saturated gas specific enthalpy refers to the enthalpy value of a unit mass of saturated gas refrigerant; superheated steam specific enthalpy refers to the enthalpy value of a unit mass of superheated steam; and superheated steam specific entropy refers to the entropy value of a unit mass of superheated steam.

[0174] For each preset condition, the thermophysical parameters and mathematical model were fitted. By using the specific entropy conservation of the isentropic compression process (Equation 10) and the fitting formula of superheated steam specific entropy with temperature and pressure, the exhaust temperature of the final stage compression was deduced. By calculating the specific enthalpy difference of each stage of isentropic compression step by step, and then combining the intake volume ratio of each stage (correcting for the throttling effect), the total specific work was obtained by weighted summation.

[0175] In one embodiment of this example, taking R134a refrigerant (applicable range: -10℃~60℃, 200kPa~1000kPa) as an example, the following thermophysical property equations are obtained by fitting.

[0176] Saturation temperature ℃, and pressure The relationship between kPa and kPa is shown in formula (29):

[0177] (29);

[0178] In formula (29), a 0,Ts a 1,Ts a 2,Ts a 3,Ts a 4,Ts a 5,Ts and a 6,Ts All are constants.

[0179] The fitting coefficients for the relationship between saturation temperature and pressure are shown in Table 1:

[0180] Table 1

[0181]

[0182] Saturation pressure , kPa, and saturation temperature The relationship between , ℃, and is shown in formula (30):

[0183] (30);

[0184] The fitting coefficients for the relationship between saturation pressure and saturation temperature are shown in Table 2.

[0185] Table 2

[0186]

[0187] Specific enthalpy of saturated liquid kJ / kg, and saturation temperature The relationship between , ℃, and is shown in formula (31):

[0188] (31);

[0189] The fitting coefficients for the relationship between the specific enthalpy of saturated liquid and saturation temperature are shown in Table 3.

[0190] Table 3

[0191]

[0192] Enthalpy of saturated gas kJ / kg, and saturation temperature The relationship between , ℃, and is shown in formula (32):

[0193] (32);

[0194] The fitting coefficients for the relationship between saturated gaseous specific enthalpy and saturation temperature are shown in Table 4.

[0195] Table 4

[0196]

[0197] specific enthalpy of gas kJ / kg, relative to pressure kPa and temperature The relationship between , ℃, and is shown in formula (33):

[0198] (33);

[0199] In formula (33), a 00,hg a 01,hg a 02,hg a 10,hg a 11,hg a 12,hg and a 13,hg All are constants.

[0200] The fitting coefficients for the relationship between the specific enthalpy of superheated steam and pressure and temperature are shown in Table 5.

[0201] Table 5

[0202]

[0203] specific entropy of gas kJ / kg, relative to pressure kPa and temperature The relationship between , ℃, and is shown in formulas (34) to (37):

[0204] (34);

[0205] (35);

[0206] (36);

[0207] (37);

[0208] In formula (35) ~ formula (37), a 00,sg a 01,sg a 02,sg a 03,sg a 04,sg a 05,sg a 10,sg a 11,sg a 12,sg a 13,sg a 14,sg a 15,sg a 20,sg a 21,sg a 22,sg a 23,sg a 24,sg and a 25,sg All are constants.

[0209] Table 6 shows the fitting coefficients of the relationship between superheated steam specific entropy and pressure and temperature:

[0210] Table 6

[0211]

[0212] The exhaust temperature of the i-th stage of isentropic compression is calculated according to formulas (10) to (12). When, we can use formulas (38) to (39):

[0213] (38);

[0214] (39);

[0215] Solving for formula (40) yields:

[0216] (40);

[0217] Substituting the thermophysical parameters into the mathematical model (including the pressure ratio equations of each stage, energy balance equations, etc.), the values ​​of exhaust temperature, multi-stage isentropic compression specific work, multi-stage isentropic compression ratio refrigeration capacity, and the values ​​of each stage compression intake volume are obtained by fitting. Specifically, according to formulas (10) to (12) and formulas (38) to (40), the exhaust temperature of the i-th stage isentropic compression is calculated by conserving the specific entropy of the isentropic compression process and combining the relationship between the specific entropy of superheated steam and pressure and temperature, where the exhaust temperature of the last stage is the total exhaust temperature of the compressor; according to formulas (2) to (3), the intake volume ratio of each stage is calculated by combining the throttling energy balance equation and the saturated liquid specific enthalpy and the saturated gas specific enthalpy, and then the specific values ​​of each stage intake volume are obtained; according to formula (24), the multi-stage isentropic compression specific work is calculated; according to formulas (27) to (28), the multi-stage isentropic compression ratio refrigeration capacity is calculated based on the saturated gas specific enthalpy of the evaporator, the saturated liquid specific enthalpy of the condenser, and the intake volume ratio of each stage.

[0218] Furthermore, the ideal specific refrigeration capacity is calculated based on the difference between the specific enthalpy of the saturated liquid and the specific enthalpy of the saturated gas. The ideal specific refrigeration capacity is the heat absorbed by a unit mass of refrigerant in the evaporator as it changes from a saturated liquid to a saturated gas. It is determined solely by the saturation parameters of the evaporator and is independent of the number of compression stages. In an infinite-stage isentropic compression process, the specific entropy of the refrigerant changes continuously and uniformly. The specific isentropic compression work is the total work done in the ideal isentropic compression process, which can be calculated by integrating the specific enthalpy difference between the compressor pressure from the evaporator to the condenser. The ideal specific isentropic compression work is the minimum specific work when the total number of compression stages approaches infinity. At this point, the pressure ratio of each compression stage approaches 1, the compression process is nearly reversible, and the total work reaches its theoretical minimum. The ideal isentropic compression refrigeration efficiency is the ratio of the ideal specific refrigeration capacity to the specific isentropic compression work. This parameter is determined solely by the saturation temperatures of the evaporator and condenser and is independent of the number of compression stages. The multistage cooling capacity coefficient measures how close the actual specific cooling capacity is to the ideal value. It is the ratio of the multistage isentropic compression ratio cooling capacity to the ideal specific cooling capacity, reflecting the weight of each stage's cooling capacity in the total cooling capacity. The multistage compression work coefficient is the ratio of the specific isentropic compression work to the multistage isentropic compression ratio work, used to quantify the proportion of each stage's compression work in the total work. The isentropic compression efficiency is the ratio of the multistage isentropic compression ratio work to the actual specific work, where the actual specific work refers to the compressor's actual input specific work, which can be calculated by combining measured electrical power with the efficiency of the inverter, motor, and mechanical transmission. The isentropic compression refrigeration energy efficiency is the product of the ideal isentropic compression refrigeration energy efficiency, the multistage compression work coefficient, and the multistage cooling capacity coefficient, reflecting the ideal energy efficiency of the thermodynamic cycle at a specific number of compression stages.

[0219] This embodiment first calculates the second performance parameters, such as exhaust temperature and intake volume at each stage, by fitting thermophysical parameters and mathematical models. Then, by combining thermodynamic calculations such as enthalpy difference and integral in an ideal cycle, it derives various efficiencies and coefficients in a multi-stage compression system and finally obtains comprehensive performance indicators. This allows for a comprehensive evaluation of the compressor's performance under different preset conditions, providing accurate data support for compressor design optimization and performance improvement.

[0220] In some embodiments, step S400 may include, but is not limited to, steps S410 to S420:

[0221] Step S410: For each of the preset conditions, obtain the values ​​of multiple target performance parameters of the compressor under the preset conditions;

[0222] Step S420: Compare and evaluate the total number of compression stages corresponding to each preset condition and the value of each target performance parameter under each preset condition's refrigeration condition to obtain the evaluation result. The evaluation result indicates the impact of the total number of compression stages and the refrigeration condition on each of the multiple performance parameters.

[0223] In this embodiment, for each preset condition (i.e., a specific combination of total compression stages and refrigeration conditions), the specific values ​​of all target performance parameters are collected and calculated. Then, the influence of total compression stages on each performance parameter and the influence of refrigeration conditions on each performance parameter are compared and analyzed.

[0224] Specifically, step S420 may include, but is not limited to, steps S421 to S424:

[0225] Step S421: Compare and evaluate the values ​​of exhaust temperature, multi-stage isentropic compression specific work, multi-stage isentropic compression specific cooling capacity, and each stage's compression intake volume for each total number of compression stages to obtain a first evaluation result. The first evaluation result includes the changing trends of the exhaust temperature, specific work, specific cooling capacity, and each stage's compression intake volume as the total number of compression stages increases.

[0226] Step S422: Compare and evaluate the values ​​of the ideal isentropic compression refrigeration efficiency, the multi-stage compression work coefficient, the multi-stage refrigeration capacity coefficient, and the isentropic compression refrigeration efficiency under each total number of compression stages and each refrigeration condition to obtain a second evaluation result. The second evaluation result includes the changing trends of the ideal isentropic compression refrigeration efficiency, the multi-stage compression work coefficient, the multi-stage refrigeration capacity coefficient, and the isentropic compression refrigeration efficiency as the total number of compression stages increases.

[0227] Step S423: Based on the changing trends of the ideal isentropic compression refrigeration energy efficiency of the compressor under different refrigeration conditions, the changing trends of the multi-stage compression work coefficient, the changing trends of the multi-stage refrigeration capacity coefficient, and the changing trends of the isentropic compression refrigeration energy efficiency, a third evaluation result is obtained.

[0228] Step S424: Obtain the evaluation result based on the first evaluation result, the second evaluation result, and the third evaluation result.

[0229] In this embodiment, firstly, the values ​​of exhaust temperature, multi-stage isentropic compression specific work, multi-stage isentropic compression specific refrigeration capacity, and intake air volume of each compression stage are compared for each total number of compression stages. The trends in exhaust temperature, specific work, specific refrigeration capacity, and intake air volume of each compression stage are analyzed as the total number of compression stages increases, yielding a first evaluation result. Secondly, the values ​​of ideal isentropic compression refrigeration efficiency, multi-stage compression work coefficient, multi-stage refrigeration capacity coefficient, and isentropic compression refrigeration efficiency are compared for each total number of compression stages and under each refrigeration condition. The trends in ideal isentropic compression refrigeration efficiency, multi-stage compression work coefficient, multi-stage refrigeration capacity coefficient, and isentropic compression refrigeration efficiency are analyzed as the total number of compression stages increases, yielding a second evaluation result. Further, the trends in ideal isentropic compression refrigeration efficiency, multi-stage compression work coefficient, multi-stage refrigeration capacity coefficient, and isentropic compression refrigeration efficiency are analyzed under different refrigeration conditions, yielding a third evaluation result.

[0230] Specifically, the multi-stage isentropic compression and multi-stage throttling cooling cycle process is calculated based on a mathematical model. Figure 4 This section presents temperature-entropy diagrams of the intake and final exhaust states for each stage of a single-stage isentropic compression and a five-stage isentropic compression process with four stages of throttling cooling. Figure 4 It can be seen that for a multi-stage isentropic compression and multi-stage throttling cooling process, due to the throttling cooling process, the intake temperature of each stage is lower than the exhaust temperature of the previous stage's isentropic compression, thus the specific entropy of the intake air gradually decreases. Taking R134a refrigerant as an example, for... Figure 4 The diagram shows a 5-stage isentropic compression, 5-stage throttling, and 4-stage intermediate cooling process. Under the conditions of an evaporation temperature of -6.6℃ and a condensation temperature of 35℃, the final stage compression exhaust temperature is 38.9℃, which is 0.7℃ lower than the single-stage isentropic compression exhaust temperature of 39.6℃. While the exhaust temperature decreases somewhat, the decrease is not significant. This is related to the thermal properties of R134a. Figure 2As can be seen, the saturation temperature of the gas phase saturation line of R134a changes steeply with the specific entropy, or in other words, the range of specific entropy change is small at different saturation temperatures. Therefore, after each stage of isentropic compression, the cooling space is limited by mixing with throttling saturated steam, resulting in a small decrease in exhaust temperature after multi-stage isentropic compression and multi-stage cooling.

[0231] Figure 5 This represents the variation in the final stage discharge temperature of the compressor with different compression stages, as well as the variation in the refrigerant evaporation ratio in the evaporator. Figure 5 It can be seen that as the total number of compression stages increases, the final stage discharge temperature gradually decreases. From 2-stage compression to 5-stage compression, the change in final stage discharge temperature is very small. It can be considered that the final stage discharge temperature of 5-stage compression is close to that of infinite-stage compression. In subsequent analysis, the parameters of 5-stage compression will be equated to those of infinite-stage compression. Figure 5 As can be seen from this, when using R134a refrigerant, the total number of compressor stages does not have a significant impact on the discharge temperature of the final stage of isentropic compression for models with different compressor stages.

[0232] Depend on Figure 5 It can also be seen that from single-stage compression to five-stage compression, the evaporation ratio of the evaporator increases from 71.5% to 72.9%, which is not a significant change. This indicates that for refrigeration machines using R134a refrigerant, the specific cooling capacity of multi-stage compression cycles does not change much compared to single-stage compression cycles, and multi-stage compression has little impact on the cooling capacity of the refrigerant.

[0233] Figure 6 This represents the variation in the intake volume ratio of each stage for compressors with different total compression stages. (From...) Figure 6 It can be seen that as the total number of compressor stages increases, the intake air volume of the i-th stage decreases. For example, in the second stage of compression, the intake air volume ratio is 100%; in the third stage, it is 87.8%; and in the fifth stage, it is 80.9%. This demonstrates that the advantage of multi-stage compression and multi-stage throttling cooling is that the increase in the total number of compressor stages leads to a decrease in the intake air volume of each stage, thereby reducing the overall compression ratio.

[0234] Figure 7 This represents the changes in specific work and specific refrigeration capacity during multi-stage compression, multi-stage throttling, and isentropic compression. (From...) Figure 7 It can be seen that, with Figure 6 Correspondingly, as the total number of compressor stages increases, the isentropic compression specific work gradually decreases. For the operating condition of evaporation temperature -6.6℃ and condensation temperature 35℃, the compression specific work decreases from 28.2 kJ / kg in single-stage compression to 24.5 kJ / kg, a reduction of 13.1%, indicating that the advantage of multi-stage compression lies in the reduction of compression work. Meanwhile, the decrease in specific compression work from 2 stages to 5 stages is not significant. Figure 7It can also be seen that for refrigerators with different total compression stages, their specific refrigeration capacity does not change much, and is similar to... Figure 5 The evaporation ratio in the evaporator corresponds accordingly.

[0235] Figure 7 This paper analyzes three typical refrigeration conditions: ice storage (evaporation temperature -6.6℃, condensation temperature 35℃), building air conditioning (evaporation temperature 6℃, condensation temperature 38℃), and data center refrigeration (evaporation temperature 14℃, condensation temperature 38℃). The results show that the conclusions for all three conditions are largely consistent: the number of compression stages has little impact on the cooling capacity; the specific compression work decreases with increasing total compression stages, but the change is limited after two stages. For ice storage, the change in specific compression work from one stage to two stages is more significant. Therefore, for multi-stage compressors using R134a refrigerant, two stages already effectively utilize the advantages of multi-stage compression in reducing compression work; further increasing the total number of compressor stages has little effect.

[0236] according to Figure 8 The results show that the isentropic compression cycle refrigeration of compressors with different compression stages can be obtained. .Depend on Figure 8 It can be seen that as the total number of stages in the compressor increases, the refrigeration unit... The number of stages gradually increases, and when the total number of compressor stages reaches 5, the rate of increase tends to level off. It can be considered that at 5 stages of compression, it is close to isentropic compression with infinite compression stages. In ice storage operations, compression transitions from single-stage to two-stage compression, using isentropic compression. Increased by 5.9%, from two-stage compression to five-stage compression, isentropic compression. The increase of 3.3% indicates that starting from stage 3 compression, increasing the total number of compressor stages affects the isentropic compression of the refrigeration unit. The improvement is limited. In air conditioning and data center cooling operations, the COP increase from single-stage to two-stage compression is 8.3% and 9.2%, respectively. From two-stage to five-stage compression, the COP increase from isentropic compression cycle cooling is limited. The increases were 4.4% and 5.7% respectively, and further increasing the number of compressor stages affected the isentropic compression of the refrigeration unit. The improvement effect is not obvious.

[0237] According to formula (19), for a given evaporation and condensation temperature, the compression work coefficient is... It depends on the number of compressor stages and is an inherent performance parameter that is unrelated to the actual operation of the compressor. Figure 9 It indicates As the total number of compression stages of the compressor changes, Figure 9 The image shows three typical operating conditions: ice storage, air conditioning, and data center cooling.Figure 9 As can be seen, the compression power coefficient increases with the increase of the number of compressor stages, and the increase is related to... Figure 7 The isentropic compression ratio and compression work change trends are consistent. When the compressor changes from single-stage compression to two-stage compression, the compression power coefficient increases significantly. After that, increasing the number of compressor stages has little effect on the compression power coefficient. According to formula (22). Figure 9 middle This indicates the compression work coefficient. Coefficient of performance (COP) The overall impact on cooling performance shows that... Change curve and The similarity in the change curves indicates that different stages of compressors... It has little impact on the performance of the refrigeration unit.

[0238] Isentropic compression refrigeration This is an inherent characteristic of the refrigeration unit and is unrelated to the actual operating performance of the compressor. Ideal isentropic compression refrigeration. Depending on the saturation temperatures of the evaporator and condenser, and considering the coefficient of performance (COP) and compression work coefficient for different compression stages, isentropic compression refrigeration is discussed for single-stage, two-stage, and three-stage compressors, and for three different refrigeration temperature conditions. The curves showing the change with condensation temperature are as follows: Figure 10 As shown. For the same refrigeration temperature condition, the influence of the number of compression stages of the three compressors is relatively small, while the refrigeration temperature has a greater impact on isentropic compression refrigeration. The impact is significant. For all operating conditions, as the condensing temperature increases, isentropic compression refrigeration... Decrease. From Figure 10 It can be seen from this that the refrigeration temperature and condensation temperature affect the isentropic compression refrigeration of the refrigerator. The impact of the compressor stage number is far greater than the impact of the number of compressor stages. It can be considered that, within a certain range of refrigeration and cooling temperatures, rationally operating the refrigeration system parameters will improve isentropic compression refrigeration. Choosing the right compressor stage is just as important as selecting the number of compressor stages.

[0239] In this embodiment, the first evaluation results include: as the total number of compression stages increases, the exhaust temperature of the compressor's final stage gradually decreases; as the total number of compression stages increases, the multi-stage isentropic compression ratio work gradually decreases; as the total number of compression stages increases, the multi-stage isentropic compression ratio cooling capacity slightly increases, but the change is small; as the total number of compression stages increases, the proportion of the intake air volume of the same stage gradually decreases.

[0240] The second assessment results include: the ideal isentropic compression refrigeration efficiency is determined only by the saturation temperature of the evaporator and condenser, and is independent of the total number of compression stages; as the total number of compression stages increases, the multistage compression work coefficient gradually increases and approaches 1; as the total number of compression stages increases, the multistage refrigeration capacity coefficient slightly increases and approaches 1; as the total number of compression stages increases, the isentropic compression refrigeration efficiency gradually increases and approaches the ideal isentropic compression refrigeration efficiency.

[0241] The third assessment results include: the refrigeration efficiency of ideal isentropic compression increases significantly with increasing evaporation temperature or decreasing condensation temperature; the multi-stage compression work coefficient is less affected by refrigeration conditions, and the compression work coefficient mainly depends on the number of stages and has a weak correlation with the operating conditions; the multi-stage refrigeration capacity coefficient is minimally affected by refrigeration conditions; the trend of isentropic compression refrigeration efficiency is consistent with that of ideal isentropic compression refrigeration efficiency, that is, it increases with increasing evaporation temperature or decreasing condensation temperature, and increases with increasing number of stages under the same operating conditions.

[0242] Based on the first, second, and third evaluation results, the overall influence of the total number of compression stages and refrigeration conditions on performance parameters is summarized as follows: The influence of the total number of compression stages is as follows: low-stage compression (1-2 stages) significantly reduces exhaust temperature and specific work, improving isentropic compression refrigeration efficiency, making it the most cost-effective optimization method; the optimization effect of high-stage compression (2-5 stages) slows down, with 5 stages approaching the theoretical limit of infinite compression, and further increasing the number of stages has limited performance improvement; the total number of compression stages significantly affects the intake volume distribution at each stage, but has a relatively small impact on specific refrigeration capacity. The influence of refrigeration conditions is as follows: evaporation temperature and condensation temperature are the core factors determining ideal isentropic compression refrigeration efficiency, and their influence is much greater than that of the total number of compression stages; isentropic compression refrigeration efficiency increases significantly with increasing evaporation temperature or decreasing condensation temperature, and optimizing operating parameters (such as lowering the condensation temperature) is more effective in improving actual efficiency than increasing the number of compression stages; the multi-stage compression work coefficient and refrigeration capacity coefficient are less affected by operating conditions and mainly depend on the total number of compression stages.

[0243] This embodiment analyzes the impact of the total number of compression stages and refrigeration conditions on various performance parameters, revealing the trend of compressor performance changes with these factors. This systematic analysis method helps to deeply understand the performance characteristics of the compressor, providing a scientific basis for compressor design optimization and operating parameter selection. Furthermore, by comprehensively analyzing multiple target performance parameters, the limitations of single-index evaluation are avoided, resulting in more comprehensive and accurate performance evaluation results.

[0244] In some embodiments, step S400 may be followed by steps S500 to S600, including but not limited to:

[0245] Step S500: Obtain the value of the isentropic compression efficiency of the compressor under each preset condition;

[0246] Step S600: Compare and analyze the total number of compression stages corresponding to each preset condition and the value of the isentropic compression efficiency under the refrigeration condition corresponding to each preset condition, and take the total number of compression stages and the refrigeration condition corresponding to the maximum value of the isentropic compression efficiency as the target total number of compression stages and the target refrigeration condition of the compressor.

[0247] In this embodiment, after comparing and evaluating the values ​​of multiple target performance parameters of the compressor under each preset condition, and obtaining the evaluation results, the isentropic compression efficiency of the compressor under each preset condition is obtained. Isentropic compression efficiency is an important indicator reflecting the actual operating performance of the compressor; a higher value indicates higher compressor operating efficiency. The isentropic compression efficiency values ​​under different total compression stages are compared to analyze the impact of the total compression stages on isentropic compression efficiency. The isentropic compression efficiency values ​​under different refrigeration conditions are also compared to analyze the impact of the refrigeration conditions on isentropic compression efficiency. The interaction between the total compression stages and the refrigeration conditions on isentropic compression efficiency is comprehensively analyzed. The total compression stages corresponding to the maximum value of the isentropic compression efficiency, along with the refrigeration condition, are taken as the target total compression stages and target operating condition of the compressor. The target total compression stages and target operating condition represent the optimal configuration for compressor operating efficiency under current conditions, providing a basis for compressor design, selection, and operational optimization.

[0248] Specifically, based on the analysis of the inherent characteristics of the refrigeration thermodynamic cycle, the actual operating efficiency of the refrigeration compressor is analyzed. IPLV or NPLV are typically used to represent the performance of the chiller under different operating conditions. IPLV (Integrated Part Load Value) is a single numerical value representing the part load efficiency of an air-conditioning chiller unit, calculated by weighting the cumulative load percentages under various load conditions based on the unit's performance coefficient value under partial load. NPLV (Nonstandard Part Load Value) is mainly used in atypical cooling tower applications or when the cooling water temperature does not meet standard specifications. It considers the equipment performance under non-standard water temperature conditions and calculates the energy efficiency value using adjusted temperature conditions to provide a more accurate performance assessment under non-standard conditions.

[0249] Table 7 shows the COP values ​​of two centrifugal chiller models under different load rate conditions, including four refrigeration load rate conditions. Chiper A is a variable frequency two-stage compression centrifugal chiller, and chiller B is a variable frequency magnetic levitation single-stage compression centrifugal chiller.

[0250] Table 7

[0251]

[0252] Generally speaking, the efficiency of a frequency converter is The efficiency is 97.0%~98.0% for AC motors. 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 embodiment 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%.

[0253] According to formula (23), the isentropic compression efficiency of the compressor under the corresponding operating condition can be obtained. As can be seen from Table 7, for the two-stage compression refrigerator A, its maximum isentropic compression efficiency is... 2. The isentropic compression efficiency appears at 100% load rate. At 75% and 50% load rates, the isentropic compression efficiency is also greater than 80%, close to that at 100% load rate. However, at 25% load rate, the isentropic compression efficiency drops significantly. This indicates that this type of refrigeration unit should be avoided from operating at lower loads as much as possible.

[0254] For a single-stage compression refrigerator B, the maximum isentropic compression efficiency is... 1 also appears under 100% load rate design conditions. The isentropic compression efficiency is also relatively high at 75% and 50% load rates. The isentropic compression efficiency at 25% load rate is the same as that of the A-type refrigerator, with a significant decrease in efficiency.

[0255] It should be noted that the isentropic compression efficiency of single-stage compression 1 and two-stage compression 2. This only represents the isentropic compression efficiency of the compressor. To evaluate the refrigeration COP of a refrigerator, the compression work coefficient and the refrigeration coefficient must also be considered. For example, as shown in Table 7, at 100% load, although single-stage compression... 1 is 92.2%, higher than two-stage compression. 2 is 85.1%, but dual-stage compression 2 is 8.67, single-stage compression The coefficient of performance (COP) is 7.21, meaning the COP of a two-stage refrigeration system (6.64) is greater than that of a single-stage refrigeration system (6.09). Therefore, the impact of the compressor's isentropic compression coefficient and the number of compression stages on the performance of the refrigeration unit needs to be considered comprehensively.

[0256] In summary, the isentropic compression efficiency of the compressor By removing the complex influencing factors on refrigeration machine performance and shielding the impact of refrigerant environmental parameters on the thermodynamic cycle performance of the refrigeration machine, and only considering the actual operating performance of the compressor, the universality of compressor operating performance evaluation can be greatly improved, making it convenient for the design and operation analysis of refrigeration centrifugal compressors.

[0257] This embodiment comprehensively compares and evaluates the compressor's performance under different compression stages and operating conditions through isentropic compression efficiency, thereby determining the compressor's optimal operating parameters. This avoids the limitations of relying solely on experience or local indicators for selection, providing an objective basis for compressor design optimization and rational selection, and contributing to improved overall compressor performance and operating efficiency.

[0258] This application proposes definitions for the ideal refrigeration COP of an infinite-stage compression and infinite-stage throttling cooling thermodynamic cycle, the multi-stage compression work coefficient, the multi-stage refrigeration capacity coefficient, the isentropic compression efficiency of a multi-stage compression and multi-stage throttling cooling compressor, and the refrigeration COP of a multi-stage compression and multi-stage throttling cooling thermodynamic cycle. These definitions are used to analyze the efficiency of refrigeration machines and compressors, and to establish corresponding mathematical models. The thermal properties of refrigerant R134a are fitted, and the fitting formula can accurately represent the relationship between the specific entropy of superheated vapor and temperature and pressure. Through the establishment of mathematical models, compressor performance is analyzed, including the compressor discharge temperature, specific work, specific refrigeration capacity, and intake volume of each stage of compression for a multi-stage compression and multi-stage throttling cooling compressor, as well as the ideal refrigeration COP, multi-stage compression work coefficient, multi-stage refrigeration capacity coefficient, and refrigeration COP of an infinite-stage compression and infinite-stage throttling cooling thermodynamic cycle. This paper analyzes newly proposed parameters for refrigeration machines and compressors, such as the isentropic compression efficiency of multi-stage compression and multi-stage throttling cooling compressors, and studies the influence of different total compression stages in compressors. Based on refrigeration machine COP data, and according to mathematical models, the isentropic compression efficiency of single-stage and two-stage compression refrigeration machines is obtained. This allows for horizontal comparison of compressors with different compression stages, as well as comparison of the same compressor under different operating conditions. The factors affecting the thermodynamic cycle efficiency (chilled water temperature and cooling water temperature) of refrigeration machine COP performance are separated, and the compressor compression efficiency is obtained based on the refrigeration machine COP. The embodiments of this application have universality for evaluating the compression efficiency of multi-stage compression and multi-stage throttling cooling compressors, and provide a performance analysis method for analyzing centrifugal refrigeration compressors with multi-stage compression and multi-stage throttling cooling. This is a powerful tool for the design, selection, and operational analysis and optimization of refrigeration compressors.

[0259] Please see Figure 11 This application embodiment also provides a compressor performance evaluation device 700, which can implement the above-described compressor performance evaluation method. The device includes:

[0260] The first construction module 10 is used to construct the thermodynamic cycle flow of the compressor under each preset condition based on the compression process of the compressor under multiple preset conditions. The total number of compression stages and at least one of the refrigeration conditions are different under different preset conditions. The refrigeration condition corresponds to an evaporation temperature and a condensation temperature.

[0261] The second construction module 20 is used to construct a mathematical model of the compressor under the preset conditions based on the thermodynamic cycle flow of the compressor under the preset conditions for each preset condition. The mathematical model includes multiple target performance parameters for evaluating the performance of the compressor.

[0262] The fitting module 30 is used to fit the mathematical model of the compressor under the preset conditions with the thermophysical parameters of the refrigerant of the compressor to obtain the value of each target performance parameter of the compressor under the preset conditions.

[0263] The evaluation module 40 is used to compare and evaluate the values ​​of multiple target performance parameters of the compressor under each preset condition, and obtain the evaluation result.

[0264] In some implementations, the first building module 10 may include:

[0265] The first construction submodule is used to decompose the compression process into multiple isentropic compression stages according to the total number of compression stages of the compressor under each preset condition, and to introduce a throttling cooling process between each isentropic compression stage to construct the thermodynamic cycle process.

[0266] In some implementations, the second building module 20 may include:

[0267] The first acquisition submodule is used to acquire multiple first performance parameters of the compressor under each preset condition, wherein the first performance parameters are calculated based on the existing performance parameters of the compressor.

[0268] The second construction submodule is used to construct the mathematical model of the compressor under the preset conditions based on the thermodynamic cycle process and multiple first performance parameters.

[0269] In some implementations, the fitting module 30 may include:

[0270] The fitting submodule is used to perform the following processing for each of the preset conditions: the thermophysical parameters include saturation pressure, saturation temperature, saturated liquid specific enthalpy, saturated gas specific enthalpy, superheated steam specific enthalpy, and superheated steam specific entropy; the multiple target performance parameters include multiple first performance parameters and multiple second performance parameters; the multiple first performance parameters include ideal isentropic compression refrigeration efficiency, multi-stage compression work coefficient, multi-stage refrigeration capacity coefficient, isentropic compression efficiency, and isentropic compression refrigeration efficiency; the multiple second performance parameters include exhaust temperature, multi-stage isentropic compression specific work, multi-stage isentropic compression ratio refrigeration capacity, and each stage compression intake volume; the saturation pressure, saturation temperature, saturated liquid specific enthalpy, saturated gas specific enthalpy, superheated steam specific enthalpy, superheated steam specific entropy, and the mathematical model are fitted to obtain the values ​​of the exhaust temperature, the multi-stage isentropic compression specific work, the multi-stage isentropic compression ratio refrigeration capacity, and the each stage compression intake volume;

[0271] The first calculation submodule is used to take the difference between the saturated liquid specific enthalpy and the saturated gas specific enthalpy as the value of the ideal specific cooling capacity;

[0272] The second calculation submodule is used to integrate the specific enthalpy difference between the evaporator pressure and the condenser pressure of the compressor as the value of the specific isentropic compression work.

[0273] The third calculation submodule is used to take the ratio of the ideal specific cooling capacity to the specific isentropic compression work as the value of the ideal isentropic compression cooling energy efficiency.

[0274] The fourth calculation submodule is used to take the ratio of the value of the multi-stage isentropic compression ratio refrigeration capacity to the value of the ideal ratio refrigeration capacity as the value of the multi-stage refrigeration capacity coefficient;

[0275] The fifth calculation submodule is used to take the ratio of the value of the isentropic compression work to the value of the multi-stage isentropic compression work as the value of the multi-stage compression work coefficient;

[0276] The sixth calculation submodule is used to take the ratio of the multi-level isentropic compression specific work to the actual specific work as the value of the isentropic compression efficiency.

[0277] The seventh calculation submodule is used to obtain the value of the isentropic compression refrigeration energy efficiency based on the product of the value of the ideal isentropic compression refrigeration energy efficiency, the value of the multi-stage compression work coefficient, and the value of the multi-stage refrigeration capacity coefficient.

[0278] In some implementations, the evaluation module 40 may include:

[0279] The second acquisition submodule is used to acquire, for each of the preset conditions, the values ​​of multiple target performance parameters of the compressor under the preset conditions;

[0280] An evaluation submodule is used to compare and evaluate the total number of compression stages corresponding to each preset condition and the value of each target performance parameter under each preset condition's refrigeration condition, and obtain the evaluation result. The evaluation result indicates the impact of the total number of compression stages and the refrigeration condition on each of the multiple performance parameters.

[0281] In some implementations, the evaluation submodule may include:

[0282] The first evaluation unit is used to compare and evaluate the values ​​of exhaust temperature, multi-stage isentropic compression specific work, multi-stage isentropic compression specific cooling capacity, and the compression intake volume of each stage under each total number of compression stages, and obtain a first evaluation result. The first evaluation result includes the changing trends of the exhaust temperature, specific work, specific cooling capacity, and compression intake volume of each stage as the total number of compression stages increases.

[0283] The second evaluation unit is used to compare and evaluate the values ​​of the ideal isentropic compression refrigeration energy efficiency, the multi-stage compression work coefficient, the multi-stage refrigeration capacity coefficient, and the isentropic compression refrigeration energy efficiency under each total number of compression stages and each refrigeration condition, and obtain a second evaluation result. The second evaluation result includes the changing trends of the ideal isentropic compression refrigeration energy efficiency, the multi-stage compression work coefficient, the multi-stage refrigeration capacity coefficient, and the isentropic compression refrigeration energy efficiency as the total number of compression stages increases.

[0284] The third evaluation unit is used to obtain the third evaluation result based on the changing trend of the ideal isentropic compression refrigeration energy efficiency of the compressor under different refrigeration conditions, the changing trend of the multi-stage compression work coefficient, the changing trend of the multi-stage refrigeration capacity coefficient, and the changing trend of the isentropic compression refrigeration energy efficiency.

[0285] The result generation unit is used to obtain the evaluation result based on the first evaluation result, the second evaluation result, and the third evaluation result.

[0286] In some embodiments, the device may further include:

[0287] The acquisition module is used to acquire the value of the isentropic compression efficiency of the compressor under each preset condition;

[0288] The analysis module is used to compare and analyze the total number of compression stages corresponding to each preset condition and the value of the isentropic compression efficiency under the refrigeration condition corresponding to each preset condition, and to take the total number of compression stages and the refrigeration condition corresponding to the maximum value of the isentropic compression efficiency as the target total number of compression stages and the target refrigeration condition of the compressor.

[0289] The specific implementation of this compressor performance evaluation device is basically the same as the specific implementation of the compressor performance evaluation method described above, and will not be repeated here.

[0290] 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 compressor performance evaluation method. This electronic device can be any smart terminal, including tablet computers, in-vehicle computers, etc.

[0291] Please see Figure 12 , Figure 12 The hardware structure of an electronic device according to another embodiment is illustrated. The electronic device includes:

[0292] 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.

[0293] 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 applications. 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 compressor performance evaluation method of the embodiments of this application.

[0294] The 803 input / output interface is used to implement information input and output.

[0295] 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.).

[0296] Bus 805 transmits information between various components of the device (e.g., processor 801, memory 802, input / output interface 803, and communication interface 804);

[0297] The processor 801, memory 802, input / output interface 803, and communication interface 804 are connected to each other within the device via bus 805.

[0298] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described compressor performance evaluation method.

[0299] 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.

[0300] The compressor performance evaluation method, apparatus, electronic device, and storage medium provided in this application construct a thermodynamic cycle flow based on the compressor's compression process under multiple preset conditions. These preset conditions differ in at least one of the total number of compression stages and refrigeration conditions, thus comprehensively considering the impact of different operating conditions and compression stages on compressor performance. For each preset condition, a mathematical model of the compressor is established based on the constructed thermodynamic cycle flow. This mathematical model includes multiple target performance parameters for evaluating compressor performance, comprehensively reflecting the compressor's performance characteristics under those conditions. The mathematical model of the compressor under preset conditions is fitted with the thermophysical parameters of the refrigerant to obtain specific values ​​for each target performance parameter. This combination of theoretical model and actual operating conditions improves the accuracy of the evaluation results. Finally, the performance of the compressor under each preset condition is compared and evaluated to obtain the final evaluation result. By comparing and analyzing the performance parameters under different conditions, the compressor performance can be comprehensively evaluated, and the optimal operating conditions can be identified. This application, by constructing thermodynamic cycle flows and mathematical models under different preset conditions, and combining them with refrigerant thermophysical parameters to obtain target performance values ​​and conduct comparative evaluations, can accurately quantify compressor performance and eliminate external environmental interference.

[0301] 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.

[0302] 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.

[0303] 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.

[0304] 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.

[0305] 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.

[0306] 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.

[0307] 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.

[0308] 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.

[0309] 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.

[0310] 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.

[0311] 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 evaluating the performance of a compressor, characterized by, The method comprises: According to the compression process of the compressor under a plurality of preset conditions, a thermodynamic cycle process of the compressor under each of the preset conditions is constructed, wherein at least one of the total number of compression stages and the refrigeration working condition included in different preset conditions is different, and the refrigeration working condition corresponds to an evaporation temperature and a condensation temperature; For each of the preset conditions, a mathematical model of the compressor under the preset condition is constructed based on the thermodynamic cycle process of the compressor under the preset condition, and the mathematical model includes a plurality of target performance parameters for evaluating the performance of the compressor; The mathematical model of the compressor under the preset condition is fitted with the thermophysical property parameters of the refrigerant of the compressor to obtain the value of each of the target performance parameters of the compressor under the preset condition; The values of a plurality of target performance parameters of the compressor under each of the preset conditions are evaluated to obtain an evaluation result; The thermophysical property parameters include saturated pressure, saturated temperature, saturated liquid specific enthalpy, saturated gas specific enthalpy, superheated steam specific enthalpy, and superheated steam specific entropy, the plurality of target performance parameters include a plurality of first performance parameters and a plurality of second performance parameters, the plurality of first performance parameters include ideal isentropic compression refrigeration energy efficiency, multi-stage compression power coefficient, multi-stage refrigeration capacity coefficient, isentropic compression efficiency, and isentropic compression refrigeration energy efficiency, and the plurality of second performance parameters include exhaust temperature, multi-stage isentropic compression ratio power, multi-stage isentropic compression ratio refrigeration capacity, and the amount of each stage compression inlet gas; The fitting of the mathematical model of the compressor under the preset condition with the thermophysical property parameters of the refrigerant of the compressor to obtain the value of each of the target performance parameters of the compressor under the preset condition comprises: For each of the preset conditions, the following processing is performed: Fitting the saturated pressure, the saturated temperature, the saturated liquid specific enthalpy, the saturated gas specific enthalpy, the superheated steam specific enthalpy, the superheated steam specific entropy, and the mathematical model to obtain the value of the exhaust temperature, the value of the multi-stage isentropic compression ratio power, the value of the multi-stage isentropic compression ratio refrigeration capacity, and the value of the amount of each stage compression inlet gas; The difference between the saturated liquid specific enthalpy and the saturated gas specific enthalpy is taken as the value of the ideal specific refrigeration capacity; The integral of the specific enthalpy difference from the evaporator pressure to the condenser pressure of the compressor is taken as the value of the specific isentropic compression power; The ratio of the value of the ideal specific refrigeration capacity to the value of the specific isentropic compression power is taken as the value of the ideal isentropic compression refrigeration energy efficiency; The ratio of the value of the multi-stage isentropic compression ratio refrigeration capacity to the value of the ideal specific refrigeration capacity is taken as the value of the multi-stage refrigeration capacity coefficient; The ratio of the value of the specific isentropic compression power to the value of the multi-stage isentropic compression ratio power is taken as the value of the multi-stage compression power coefficient; The ratio of the value of the multi-stage isentropic compression ratio power to the actual specific power is taken as the value of the isentropic compression efficiency; The product of the value of the ideal isentropic compression refrigeration energy efficiency, the value of the multi-stage compression power coefficient, and the value of the multi-stage refrigeration capacity coefficient is taken as the value of the isentropic compression refrigeration energy efficiency.

2. The method of claim 1, wherein, The method comprises the following steps of: constructing a thermodynamic cycle process of the compressor under each preset condition according to a compression process of the compressor under the preset conditions; The method comprises the following steps of: decomposing the compression process into multiple isentropic compression stages according to the total compression stage number of the compressor under the preset condition, and introducing throttling cooling processes between the isentropic compression stages to construct the thermodynamic cycle process.

3. The method of claim 1, wherein, The method comprises the following steps of: constructing a mathematical model of the compressor under the preset condition based on the thermodynamic cycle process of the compressor under the preset condition. The method comprises the following steps of: obtaining multiple first performance parameters of the compressor under the preset condition, wherein the first performance parameters are calculated according to existing performance parameters of the compressor; The method comprises the following steps of: constructing the mathematical model of the compressor under the preset condition based on the thermodynamic cycle process and the multiple first performance parameters.

4. The method of claim 1, wherein, The method comprises the following steps of: obtaining values of the multiple target performance parameters of the compressor under each preset condition; The method comprises the following steps of: comparing and evaluating the total compression stage number corresponding to each preset condition and the value of each target performance parameter under the refrigeration working condition corresponding to each preset condition to obtain an evaluation result, wherein the evaluation result indicates the influence of the total compression stage number and the refrigeration working condition on each performance parameter in the multiple performance parameters. The method comprises the following steps of: comparing and evaluating the total compression stage number corresponding to each preset condition and the value of each target performance parameter under the refrigeration working condition corresponding to each preset condition to obtain an evaluation result, wherein the evaluation result indicates the influence of the total compression stage number and the refrigeration working condition on each performance parameter in the multiple performance parameters.

5. The method of claim 4, wherein, The method comprises the following steps of: comparing and evaluating the value of the exhaust temperature, the multiple-stage isentropic compression specific work, the multiple-stage isentropic compression specific refrigeration capacity and the multiple-stage compression inlet air mass under each total compression stage to obtain a first evaluation result, wherein the first evaluation result comprises the variation trend of the value of the exhaust temperature, the variation trend of the value of the specific work, the variation trend of the value of the specific refrigeration capacity and the variation trend of the value of the multiple-stage compression inlet air mass with the increase of the total compression stage number; The method comprises the following steps of: comparing and evaluating the value of the ideal isentropic compression refrigeration energy efficiency, the value of the multiple-stage compression work coefficient, the value of the multiple-stage refrigeration capacity coefficient and the value of the isentropic compression refrigeration energy efficiency under each total compression stage and each refrigeration working condition to obtain a second evaluation result, wherein the second evaluation result comprises the variation trend of the value of the ideal isentropic compression refrigeration energy efficiency, the variation trend of the value of the multiple-stage compression work coefficient, the variation trend of the value of the multiple-stage refrigeration capacity coefficient and the variation trend of the value of the isentropic compression refrigeration energy efficiency with the increase of the total compression stage number; The method comprises the following steps of: obtaining a third evaluation result according to the variation trend of the value of the ideal isentropic compression refrigeration energy efficiency, the variation trend of the value of the multiple-stage compression work coefficient, the variation trend of the value of the multiple-stage refrigeration capacity coefficient and the variation trend of the value of the isentropic compression refrigeration energy efficiency of the compressor under different refrigeration working conditions. ​ According to the first evaluation result, the second evaluation result and the third evaluation result, the evaluation result is obtained.

6. The method of claim 4, wherein, After the performance comparison evaluation on the values of the plurality of target performance parameters of the compressor under each of the preset conditions is performed, the method further comprises: obtaining the value of the isentropic compression efficiency of the compressor under each of the preset conditions; comparing and analyzing the total compression stage number corresponding to each of the preset conditions and the value of the isentropic compression efficiency under the refrigeration working condition corresponding to each of the preset conditions, and taking the total compression stage number corresponding to the maximum value of the isentropic compression efficiency and the refrigeration working condition as the target total compression stage number and the target working condition of the compressor.

7. A compressor performance evaluation device characterized by comprising: The device comprises: a first construction module configured to construct, according to a compression process of the compressor under a plurality of preset conditions, a thermodynamic cycle flow process of the compressor under each of the preset conditions, wherein at least one of the total compression stage number and the refrigeration working condition included in different preset conditions is different, and the refrigeration working condition corresponds to one evaporation temperature and one condensation temperature; a second construction module configured to, for each of the preset conditions, construct, based on the thermodynamic cycle flow process of the compressor under the preset condition, a mathematical model of the compressor under the preset condition, wherein the mathematical model comprises a plurality of target performance parameters for evaluating the performance of the compressor. The fitting module is configured to fit the mathematical model of the compressor under the preset condition with thermophysical parameters of refrigerant of the compressor to obtain a value of each target performance parameter of the compressor under the preset condition; the thermophysical parameters include saturated pressure, saturated temperature, saturated liquid specific enthalpy, saturated gas specific enthalpy, superheated steam specific enthalpy and superheated steam specific entropy, the target performance parameters include first performance parameters and second performance parameters, the first performance parameters include ideal isentropic compression refrigeration energy efficiency, multi-stage compression power coefficient, multi-stage refrigeration capacity coefficient, isentropic compression efficiency and isentropic compression refrigeration energy efficiency, and the second performance parameters include exhaust temperature, multi-stage isentropic compression ratio power, multi-stage isentropic compression ratio refrigeration capacity and compression inlet air quantity of each stage; for each preset condition, the following processing is performed: fitting the saturated pressure, the saturated temperature, the saturated liquid specific enthalpy, the saturated gas specific enthalpy, the superheated steam specific enthalpy, the superheated steam specific entropy and the mathematical model to obtain a value of the exhaust temperature, a value of the multi-stage isentropic compression ratio power, a value of the multi-stage isentropic compression ratio refrigeration capacity and a value of the compression inlet air quantity of each stage; taking a difference between the saturated liquid specific enthalpy and the saturated gas specific enthalpy as a value of ideal specific refrigeration capacity; taking an integral of a specific enthalpy difference from an evaporator pressure to a condenser pressure of the compressor as a value of specific isentropic compression power; taking a ratio between the value of the ideal specific refrigeration capacity and the value of the specific isentropic compression power as a value of the ideal isentropic compression refrigeration energy efficiency; taking a ratio between the value of the multi-stage isentropic compression ratio refrigeration capacity and the value of the ideal specific refrigeration capacity as a value of the multi-stage refrigeration capacity coefficient; taking a ratio between the value of the specific isentropic compression power and the value of the multi-stage isentropic compression ratio power as a value of the multi-stage compression power coefficient; taking a ratio between the value of the multi-stage isentropic compression ratio power and actual specific power as a value of the isentropic compression efficiency; and obtaining a value of the isentropic compression refrigeration energy efficiency according to a product of the value of the ideal isentropic compression refrigeration energy efficiency, the value of the multi-stage compression power coefficient and the value of the multi-stage refrigeration capacity coefficient; The evaluation module is configured to perform performance comparison evaluation on the values of the target performance parameters of the compressor under each preset condition to obtain an evaluation result.

8. An electronic device, comprising: The electronic device includes a memory and a processor, the memory stores a computer program, and the processor implements the compressor performance evaluation method in any one of claims 1 to 6 when executing the computer program.

9. A computer-readable storage medium storing a computer program, the computer program comprising instructions that, when executed by a computer, cause the computer to perform the method of any one of claims 1 to 8. The computer program is executed by the processor to implement the compressor performance evaluation method in any one of claims 1 to 6.

Images