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

Abstract

The embodiment of the invention provides a compressor performance evaluation method and device, electronic equipment and a storage medium, and belongs to the technical field of refrigeration. The method comprises the following steps: constructing a thermodynamic cycle flow of the compressor under each preset condition according to a compression process of the compressor under a plurality of preset conditions; for each preset condition, based on the thermodynamic cycle flow of the compressor under the preset condition, a mathematical model of the compressor under the preset condition is constructed, and the mathematical model comprises a plurality of target performance parameters used for evaluating the performance of the compressor; fitting the mathematical model of the compressor under the preset condition 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 condition; and performing performance comparison evaluation on the values of the multiple target performance parameters of the compressor under each preset condition to obtain an evaluation result. According to the embodiment of the invention, the compressor performance can be quantitatively evaluated.

Description

Technical Field

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

[0002] In the field of refrigeration engineering, large-scale chillers typically utilize steam centrifugal compressors, including single-stage, two-stage, and three-stage compression systems. The energy efficiency of a chiller is primarily assessed by its coefficient of performance (COP). This parameter is closely related not only to external system parameters such as the saturation temperature of the evaporator and condenser, but also to core chiller internal parameters such as compressor efficiency. Compressor efficiency, a key indicator for evaluating the rationality of chiller design and operating performance, is significantly correlated with factors such as the compressor characteristic curve, intake and exhaust parameters, and compressor control strategy.

[0003] However, when using chiller COP (Cost-of-Operation) performance analysis, the compressor's compression efficiency cannot be directly determined by the COP value, as it is influenced by the thermodynamic cycle efficiency determined by the temperatures of the chilled and cooling water. Traditional compressor efficiency definitions (such as single-stage isentropic compression efficiency and multi-stage compression efficiency) have significant limitations when evaluating compressors with multi-stage compression and multi-stage throttling cooling, and cannot accurately reflect the actual operating efficiency of such compressors. Therefore, when analyzing chiller design parameters and operating performance data, there is a lack of tools that can effectively quantify compressor performance, making it difficult to achieve a quantitative assessment of compressor performance. Summary of the Invention

[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 in the prior art that it is difficult to quantitatively evaluate compressor performance.

[0005] To achieve the above objectives, a first aspect of an embodiment of the present application provides a compressor performance evaluation method, the method comprising: constructing a thermodynamic cycle flow of the compressor under each of the preset conditions according to the compression process of the compressor under a plurality of preset conditions, wherein the different preset conditions include at least one of a total number of compression stages and a refrigeration operating condition, and the refrigeration operating condition corresponds to an evaporation temperature and a condensation temperature; For each of the preset conditions, based on the thermodynamic cycle process of the compressor under the preset conditions, a mathematical model of the compressor under the preset conditions is constructed, wherein the mathematical model includes a plurality of target performance parameters for evaluating the performance of the compressor; Fitting the mathematical model of the compressor under the preset conditions with the thermophysical property parameters of the refrigerant of the compressor to obtain the value of each target performance parameter of the compressor under the preset conditions; A performance comparison evaluation is performed on the values ​​of the plurality of target performance parameters of the compressor under each of the preset conditions to obtain an evaluation result.

[0006] In some embodiments, constructing a thermodynamic cycle flow of the compressor under each of the preset conditions according to the compression process of the compressor under the multiple preset conditions includes: 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.

[0007] In some embodiments, for each of the preset conditions, constructing a mathematical model of the compressor under the preset conditions based on the thermodynamic cycle process of the compressor under the preset conditions includes: For each of the preset conditions, obtaining a plurality of first performance parameters of the compressor under the preset conditions, where the first performance parameters are calculated based on existing performance parameters of the compressor; The mathematical model of the compressor under the preset conditions is constructed based on the thermodynamic cycle process and the plurality of the first performance parameters.

[0008] In some embodiments, the thermophysical property parameters include saturation pressure, saturation 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 work coefficient, multi-stage refrigeration capacity coefficient, isentropic compression efficiency, and isentropic compression refrigeration energy efficiency; the plurality of second performance parameters include exhaust temperature, multi-stage isentropic compression specific work, multi-stage isentropic compression specific refrigeration capacity, and compression intake volume at each stage; The fitting of 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 includes: For each of the preset conditions, the following processing is performed: Fitting the saturation pressure, the saturation 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 specific work, a value of the multi-stage isentropic compression specific refrigeration capacity, and a value of the compression intake volume of each stage; Taking the difference between the saturated liquid specific enthalpy and the saturated gas specific enthalpy as the value of the ideal specific cooling capacity; The integral of the specific enthalpy difference from the evaporator pressure to the condenser pressure of the compressor is used as the value of the specific isentropic compression work; The ratio of the ideal specific cooling capacity to the specific isentropic compression work is used as the ideal isentropic compression refrigeration energy efficiency; The ratio of the multi-stage isentropic compression ratio cooling capacity to the ideal ratio cooling capacity is used as the multi-stage cooling capacity coefficient; The ratio of the value of the isentropic compression work to the value of the multi-stage isentropic compression work coefficient is used as the value of the multi-stage compression work coefficient; The ratio of the multi-stage isentropic compression specific work value to the actual specific work value is used as the isentropic compression efficiency value; The value of the isentropic compression refrigeration energy efficiency is obtained according to 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.

[0009] In some embodiments, performing a performance comparison evaluation on the values ​​of the plurality of target performance parameters of the compressor under each of the preset conditions to obtain an evaluation result includes: For each of the preset conditions, obtaining values ​​of a plurality of target performance parameters of the compressor under the preset condition; The total number of compression stages corresponding to each of the preset conditions and the value of each target performance parameter under the refrigeration condition corresponding to each of the preset conditions are compared and evaluated to obtain the evaluation result, which indicates the impact of the total number of compression stages and the refrigeration condition on each of the multiple performance parameters.

[0010] In some embodiments, the comparative evaluation of the total number of compression stages corresponding to each of the preset conditions and the value of each of the target performance parameters under the refrigeration conditions corresponding to each of the preset conditions to obtain the evaluation result includes: Comparing and evaluating the exhaust temperature, the multi-stage isentropic compression specific work, the multi-stage isentropic compression specific cooling capacity, and the values ​​of the compressed air intake volume at each stage corresponding to each total number of compression stages, to obtain a first evaluation result, the first evaluation result including a change trend of the exhaust temperature value, a change trend of the specific work value, a change trend of the specific cooling capacity value, and a change trend of the compressed air intake volume at each stage as the total number of compression stages increases; Comparing and evaluating the values ​​of the ideal isentropic compression refrigeration energy efficiency, the values ​​of the multi-stage compression work coefficient, the values ​​of the multi-stage cooling capacity coefficient, and the values ​​of the isentropic compression refrigeration energy efficiency for each total number of compression stages and each refrigeration operating condition, to obtain a second evaluation result, the second evaluation result including a changing trend of the value of the ideal isentropic compression refrigeration energy efficiency, the changing trend of the value of the multi-stage compression work coefficient, the changing trend of the value of the multi-stage cooling capacity coefficient, and the changing trend of the value of the isentropic compression refrigeration energy efficiency as the total number of compression stages increases; Obtaining a third evaluation result based on a change trend of the ideal isentropic compression refrigeration energy efficiency value of the compressor under different refrigeration conditions, a change trend of the multi-stage compression work coefficient value, a change trend of the multi-stage cooling capacity coefficient value, and a change trend of the isentropic compression refrigeration energy efficiency value; The evaluation result is obtained according to the first evaluation result, the second evaluation result and the third evaluation result.

[0011] In some embodiments, after performing a performance comparison evaluation on the values ​​of the plurality of target performance parameters of the compressor under each of the preset conditions to obtain an evaluation result, the method further includes: Obtaining a value of the isentropic compression efficiency of the compressor under each of the preset conditions; A comparative analysis is performed on the total number of compression stages corresponding to each of the preset conditions and the values ​​of the isentropic compression efficiency under the refrigeration conditions corresponding to each of the preset conditions, and the total compression stages and refrigeration conditions corresponding to the maximum value of the isentropic compression efficiency are taken as the target total compression stages and target conditions of the compressor.

[0012] To achieve the above-mentioned purpose, a second aspect of an embodiment of the present application provides a compressor performance evaluation device, comprising: a first constructing module, configured to construct, based on the compression process of the compressor under a plurality of preset conditions, a thermodynamic cycle flow of the compressor under each of the preset conditions, wherein the preset conditions include at least one of a total number of compression stages and a refrigeration operating condition, the refrigeration operating condition corresponding to an evaporation temperature and a condensation temperature; a second building module, configured to build, for each of the preset conditions, a mathematical model of the compressor under the preset conditions based on the thermodynamic cycle process of the compressor under the preset conditions, wherein the mathematical model includes a plurality of target performance parameters for evaluating the performance of the compressor; a fitting module, configured to fit the mathematical model of the compressor under the preset conditions with the thermophysical property parameters of the refrigerant of the compressor to obtain a value of each target performance parameter of the compressor under the preset conditions; An evaluation module is used to perform a performance comparison evaluation on the values ​​of the multiple target performance parameters of the compressor under each of the preset conditions to obtain an evaluation result.

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

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

[0015] The compressor performance evaluation method, device, electronic device and storage medium proposed in this application construct a thermodynamic cycle process according to the compression process of the compressor under multiple preset conditions. Different preset conditions include at least one of the total number of compression stages and the refrigeration working conditions. In this way, the influence of different working conditions and compression stages on the performance of the compressor can be fully considered. For each preset condition, a mathematical model of the compressor is established based on the constructed thermodynamic cycle process. The mathematical model includes multiple target performance parameters for evaluating the performance of the compressor, which can fully reflect the performance characteristics of the compressor under the conditions. The mathematical model of the compressor under the preset conditions is fitted with the thermophysical parameters of the refrigerant to obtain the specific value of each target performance parameter. The theoretical model is combined with the actual working conditions to improve the accuracy of the evaluation results. Finally, a performance comparison and evaluation of the multiple target performance parameters of the compressor under each preset condition is performed to obtain the final evaluation result. By comparing and analyzing the performance parameters under different conditions, the performance of the compressor can be comprehensively evaluated and the optimal working conditions can be found. By constructing thermodynamic cycle processes and mathematical models under different preset conditions, combining the refrigerant thermophysical parameters to obtain target performance values ​​and performing comparative evaluation, the present application can accurately quantify the performance of the compressor and eliminate external environmental interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 1 is a flow chart of a compressor performance evaluation method provided in an embodiment of the present application; Figure 2 Schematic diagram of a multi-stage isentropic compression and multi-stage throttling cooling thermodynamic cycle provided in an embodiment of the present application; Figure 3 Schematic diagram of a multi-stage compression and multi-stage throttling isentropic compression process provided by an embodiment of the present application; Figure 4 This is a schematic diagram of the intake state of each stage and the exhaust state of the final stage in the multi-stage isentropic compression and multi-stage throttling cooling process provided by an embodiment of the present application; Figure 5This is a schematic diagram of the final exhaust temperature and evaporation ratio of the evaporator in the multi-stage isentropic compression and multi-stage throttling cooling according to an embodiment of the present application; Figure 6 This is a schematic diagram of the change in the proportion of intake air volume at each stage of multi-stage isentropic compression and multi-stage throttling cooling provided by an embodiment of the present application; Figure 7 Schematic diagram of the changes in specific work and specific cooling capacity of multi-stage compression, multi-stage throttling and cooling isentropic compression provided by an embodiment of the present application; Figure 8 Schematic diagram of the COP of multi-stage compression, multi-stage throttling, cooling and isentropic compression provided by an embodiment of the present application; Figure 9 Schematic diagram of the multi-stage compression, multi-stage throttling, cooling and isentropic compression performance provided by an embodiment of the present application; Figure 10 The effects of different chilled water temperatures and cooling water temperatures on isentropic compression refrigeration COP provided in the examples of this application are sn Schematic diagram of; Figure 11 1 is a schematic structural diagram of a compressor performance evaluation device provided in an embodiment of the present application; Figure 12 This is a schematic diagram of the hardware structure of the electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

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

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

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

[0020] In the field of refrigeration engineering, large-scale chillers typically rely on steam centrifugal compressors to achieve the refrigeration cycle. Compression methods include single-stage, two-stage, and three-stage compression. The energy efficiency of a chiller is primarily assessed through its coefficient of performance (COP). This parameter is closely related not only to external system parameters such as the saturation temperature of the evaporator and condenser, but also to core internal chiller parameters such as compressor efficiency. Compressor efficiency, a key indicator for evaluating the rationality of chiller design and operating performance, is significantly correlated with factors such as the compressor characteristic curve, intake and exhaust parameters, and control strategy.

[0021] However, existing technologies have many limitations in evaluating the performance of refrigerators and compressors: When using the COP of a chiller to analyze performance, the compressor's 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 the cooling water temperature. It is also difficult to separate the interference of external environmental factors on the compressor's own performance.

[0022] Traditional compressor efficiency definitions (such as single-stage isentropic compression efficiency, variable compression efficiency, etc.) have obvious limitations when evaluating compressors with multi-stage compression and multi-stage throttling cooling, and cannot accurately reflect the actual working efficiency of such compressors.

[0023] During the design and selection stage of the refrigerator, there is a lack of clear theoretical basis to support the decision-making on whether to adopt single-stage, two-stage or three-stage compression, which leads to a certain degree of blindness in the selection process.

[0024] When analyzing the design parameters and operating performance data of refrigerators, there is a lack of tools that can effectively quantify compressor performance, making it difficult to accurately evaluate and optimize compressor performance.

[0025] 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 improvement of operating performance.

[0026] Based on this, the embodiments of the present application provide a compressor performance evaluation method, device, electronic device, and storage medium, aiming to provide a performance evaluation method for a refrigeration centrifugal compressor with multi-stage compression and multi-stage throttling cooling, thereby resolving the problem in the prior art of difficulty in quantitatively analyzing compressor performance parameters. The embodiments of the present application propose multiple definitions of relevant performance indicators and establish corresponding mathematical models; regression is used to obtain a mathematical expression formula for the thermal properties of R134a refrigerant; based on the thermal 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 of the compressor on various performance parameters is analyzed, and the isentropic compression efficiency of both single-stage and two-stage compression refrigerators is analyzed.

[0027] The compressor performance evaluation method, device, electronic device and storage medium provided in the embodiments of the present application are specifically illustrated through the following embodiments. First, the compressor performance evaluation method in the embodiments of the present application is described.

[0028] The compressor performance evaluation method provided in the embodiment of the present application relates to the field of refrigeration technology. The compressor performance evaluation method provided in the embodiment of the present application can be applied to a terminal, can be applied to a server side, or can be software running in a terminal or a server side. In some embodiments, the terminal can be a smart phone, a tablet computer, a laptop computer, a desktop computer, etc.; the server side can be configured as an independent physical server, or can be configured as a server cluster or a distributed system composed of multiple physical servers, or can be configured as a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms; the software can be an application that implements the compressor performance evaluation method, etc., but is not limited to the above forms.

[0029] The present application can be used in many general or special computer system environments or configurations. For example: personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, distributed computing environments including any of the above systems or devices, and the like. The present application can be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, and the like that perform specific tasks or implement specific abstract data types. The present application can also be practiced in distributed computing environments in which tasks are performed by remote processing devices connected via a communication network. In a distributed computing environment, program modules can be located in local and remote computer storage media, including storage devices.

[0030] It should be noted that in each specific embodiment of the present application, when it comes to the need to perform relevant processing based on data related to the user's identity or characteristics, such as user information, user behavior data, user historical data, and user location information, the user's permission or consent will be obtained first, and the collection, use, and processing of such data will comply with relevant laws, regulations, and standards. In addition, when the embodiment of the present application needs to obtain the user's sensitive personal information, the user's separate permission or consent will be obtained through a pop-up window or by jumping to a confirmation page. After clearly obtaining the user's separate permission or consent, the necessary user-related data for the normal operation of the embodiment of the present application will be obtained.

[0031] Figure 1 This is an optional flow chart of the compressor performance evaluation method provided in an embodiment of the present application. Figure 1 The method may include but is not limited to steps S100 to S400.

[0032] Step S100, based on the compression process of the compressor under multiple preset conditions, construct a thermodynamic cycle flow of the compressor under each of the preset conditions, where different preset conditions include at least one of the total number of compression stages and the refrigeration condition, and the refrigeration condition corresponds to an evaporation temperature and a condensation temperature.

[0033] In this example, using R134a refrigerant as an example, the performance of compressors with different numbers of 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. The difference in the preset conditions is reflected in at least one of the total number of compression stages or the refrigeration operating condition, which is determined by a set of evaporating and condensing temperatures. The total number of compression stages represents the number of stages in the compression process, and the refrigeration operating condition is defined by the combination of the evaporating and condensing temperatures. This can be achieved by setting different temperature parameters and the number of compression stages.

[0034] In this embodiment, the thermodynamic cycle is a multi-stage isentropic compression and multi-stage throttling cooling thermodynamic cycle, comprising multiple isentropic compression processes and throttling cooling processes between adjacent compression processes. Specifically, multi-stage isentropic compression involves dividing the compression process into multiple stages (e.g., single-stage, double-stage, or triple-stage), with each stage performing isentropic compression (i.e., ideally reversible adiabatic compression). After each stage of compression, the pressure and temperature of the gas increase, but the subsequent cooling process lowers the temperature of the gas entering the next stage, thereby reducing the compression work of the next stage. Multi-stage throttling cooling involves throttling some of the refrigerant between each stage of compression through a throttling device (e.g., an expansion valve), generating low-temperature, low-pressure vapor. This vapor mixes with the high-temperature gas compressed in the previous stage, utilizing its cooling capacity to achieve intermediate cooling, thereby lowering the inlet temperature of the next stage. The entire cycle, comprising multiple compression processes, cooling processes, and throttling processes, ultimately completes the refrigerant evaporation, compression, condensation, and throttling processes.

[0035] Step S200: For each of the preset conditions, based on the thermodynamic cycle process of the compressor under the preset conditions, construct a mathematical model of the compressor under the preset conditions, wherein the mathematical model includes a plurality of target performance parameters for evaluating the performance of the compressor.

[0036] In this embodiment, for each preset condition, a mathematical model containing multiple target performance parameters is constructed based on its thermodynamic cycle process. A mathematical model refers to a mathematical expression established based on the thermodynamic cycle process and contains multiple target performance parameters. This model is implemented by integrating the compressor's existing performance parameters with thermodynamic relationships. This feature is used to quantify the compressor's key performance indicators. 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, multi-stage throttling cooling compressor), ideal isentropic compression refrigeration energy efficiency (ideal isentropic compression refrigeration energy efficiency of infinite-stage isentropic compression, infinite-stage throttling cooling), and isentropic compression refrigeration energy efficiency (refrigeration energy efficiency of a multi-stage isentropic compression, multi-stage throttling cooling thermodynamic cycle).

[0037] Step S300 , fitting the mathematical model of the compressor under the preset conditions with the thermophysical property parameters of the refrigerant of the compressor to obtain the value of each target performance parameter of the compressor under the preset conditions.

[0038] 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; wherein, the thermophysical parameters refer to the state parameters of the refrigerant in the thermodynamic cycle, and the thermophysical parameters may include the relationship between the saturation temperature, saturation pressure, saturated liquid specific enthalpy, saturated gas specific enthalpy, superheated steam specific entropy, etc. of the refrigerant and the temperature and pressure, etc. Specifically, they can be obtained through experimental measurement or physical 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 associating the mathematical model with the thermophysical parameters of the refrigerant, which can be achieved through numerical analysis or iterative algorithm, and is used to solve the actual values ​​of the target performance parameters, such as exhaust temperature and compression work. Based on the above thermophysical parameters, combined with the formulas in the mathematical model, the specific values ​​of the target performance parameters such as specific work at each level, specific cooling capacity, compression work coefficient, cooling capacity coefficient, etc. can be calculated.

[0039] Step S400 , performing a performance comparison evaluation on the values ​​of the plurality of target performance parameters of the compressor under each of the preset conditions to obtain an evaluation result.

[0040] In this embodiment, a performance comparison evaluation is performed on the values ​​of multiple target performance parameters of the compressor under each preset condition to obtain evaluation results. The evaluation results can be used to analyze the performance of the compressor under different compression stages and refrigeration conditions, providing a basis for compressor design, selection, and operation optimization.

[0041] Specifically, the evaluation results may include: by analyzing the changing trends of exhaust temperature, specific work, COP under different numbers of stages (such as single-stage, two-stage, and five-stage), the impact of the total number of compression stages on performance is obtained (for example, as the number of stages increases, the specific work gradually decreases, and 5-stage compression approaches the optimization limit of infinite-stage compression); by comparing the changes in isentropic compression efficiency under different evaporation temperatures / condensing temperatures (such as ice storage conditions: -6.6℃ / 35℃; air-conditioning conditions: 6℃ / 38℃), the impact of refrigeration conditions on performance is obtained; based on the isentropic compression efficiency, excluding external circulation factors, the actual operating efficiency of compressors under different numbers of stages or different operating conditions is directly compared to achieve a horizontal comparison of compressor efficiency.

[0042] This example constructs a thermodynamic cycle model under multiple preset conditions and combines it with refrigerant property parameter fitting to effectively isolate the influence of external operating conditions and accurately evaluate compressor performance. Comparative analysis of multiple target performance parameters comprehensively reflects compressor performance characteristics, providing a theoretical basis for compressor design optimization and selection.

[0043] In some embodiments, step S100 may include, but is not limited to, step S110: 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.

[0044] In this embodiment, for each of the preset conditions, according to the total number of compression stages n of the compressor under the preset condition (n is a positive integer, which can be 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-mentioned isentropic compression stages and throttling cooling processes, a complete multi-stage isentropic compression and multi-stage throttling cooling thermodynamic cycle process is constructed.

[0045] 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 the refrigerant under the coupling of "multi-stage compression" and "multi-stage throttling cooling". Its core is to achieve precise control and quantitative analysis of energy loss by decomposing the compression process into multiple isentropic compression stages and introducing throttling cooling between adjacent stages. 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. There is a cooling process between adjacent isentropic compression processes. The refrigerant vapor generated by the multi-stage throttling process is mixed with the exhaust gas of the previous isentropic compression process to achieve cooling of the compressor exhaust gas.

[0046] like Figure 2 As shown, Figure 2 It shows the thermodynamic cycle process of multi-stage compression and multi-stage throttling cooling. Multi-stage isentropic compression is the total compression process of refrigerant from the low pressure of evaporator to the high pressure of condenser, which can be divided into n consecutive isentropic compression stages (reversible compression, no energy loss). Each stage of compression (i) reduces the refrigerant from the inlet pressure to the high pressure. Compression to exhaust pressure During this process, specific entropy remains constant, but temperature and pressure increase. Multi-stage throttling cooling involves introducing a throttling process between two adjacent compression stages (between the exhaust of stage i and the intake of stage i+1). A portion of the refrigerant is depressurized by the throttle valve and evaporated into low-temperature steam. This steam mixes with the high-temperature exhaust of stage i, lowering the intake temperature of stage i+1 and achieving "interstage cooling." This process controls the cooling effect through energy balance (e.g., conservation of total energy before and after mixing), reducing energy consumption in the next compression stage.

[0047] like Figure 3 As shown, Figure 2 The compression process is partially magnified. Points (i) to (i)s in the figure represent 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.

[0048] In one implementation of this embodiment, for multi-stage compression, the ideal pressure ratio of each stage can be expressed as formula (1): (1); In formula (1), n ​​is the total number of compression stages; is the condenser pressure, kPa; is the evaporator pressure, kPa; and are the intake and exhaust pressures of the i-th stage compression, kPa respectively.

[0049] For the i+1th level throttling, the energy balance equation is expressed as formula (2): (2); In formula (2), is the intake air volume of the i-th stage compression, kg / s; is the i+1 stage compressed air intake volume, kg / s; 、 are the refrigerant saturated liquid specific enthalpy and saturated gas specific enthalpy corresponding to the i-th stage inlet pressure, kJ / kg; is the refrigerant saturated liquid specific enthalpy corresponding to the i-th stage exhaust pressure, kJ / kg. Formula (2) can also be expressed as formula (3): (3); Formula (3) represents the ratio of the intake volume between two adjacent compression stages.

[0050] For the throttling process, the throttling evaporation ratio is expressed as formula (4): (4); In formula (4), It indicates the mass ratio of the refrigerant converted to steam after the i+1th stage throttling process.

[0051] For the cooling process between two compression stages, the energy balance is expressed as formula (5): (5); In formula (5), is the specific heat, kJ / kg.℃; It represents the inlet temperature of the i+1 stage compression, that is, the temperature after the i-stage compression exhaust gas and the i+1-stage throttle gas are mixed; represents 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): (6); In formula (2) to formula (6), the refrigerant saturation state parameters can be expressed as formula (7) to formula (9): (7); (8); (9); In formula (7), It represents the saturation temperature corresponding to the inlet pressure of the i-th stage compression. The refrigerant saturation state parameter is a single-valued function and can be determined by the saturation temperature or saturation pressure.

[0052] For each level of isentropic compression process, it can be expressed as formula (10): (10); In formula (10), 、 are the specific entropies of the inlet and outlet gases of the i-th stage isentropic compression, respectively, in kJ / kg.℃. Both specific entropies are functions of pressure and temperature, as shown in Equations (11) and (12): (11); (12); In the known , , Under the condition of , according to the relationship between specific entropy, pressure and temperature, the exhaust temperature of the i-th stage isentropic compression can be obtained .

[0053] This example more accurately simulates the actual operation of a multi-stage compression and multi-stage throttling cooling compressor by decomposing the compression process into multiple isentropic compression stages and introducing a throttling cooling process. This construction method can reflect the changes in thermodynamic state between stages within the compressor, providing a more reasonable theoretical basis for subsequent mathematical modeling and performance evaluation. This allows for more accurate assessment of compressor performance under different preset conditions, providing strong support for compressor design optimization and selection decisions.

[0054] In some embodiments, step S200 may include but is not limited to steps S210 to S220: Step S210: for each of the preset conditions, obtaining a plurality of first performance parameters of the compressor under the preset condition, wherein the first performance parameters are calculated based on existing performance parameters of the compressor; Step S220: constructing the mathematical model of the compressor under the preset conditions based on the thermodynamic cycle process and the plurality of the first performance parameters.

[0055] 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 the refrigerant's saturated liquid specific enthalpy, saturated gas specific enthalpy, superheated steam specific enthalpy, superheated steam specific entropy, etc.); and cycle process parameters (including the intake volume of each stage of compression, the throttling evaporation ratio, and the isentropic compression exhaust temperature, etc.). Based on these existing performance parameters, a first performance parameter is derived and calculated using thermodynamic formulas. This 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 the framework, the first performance parameters are linked through equations to form a complete mathematical model.

[0056] Specifically, the first performance parameter includes ideal isentropic compression refrigeration energy efficiency, multi-stage compression work coefficient, multi-stage refrigeration capacity coefficient, isentropic compression efficiency and isentropic compression refrigeration energy efficiency. It refers to the ideal refrigeration coefficient of an infinite-stage compression and infinite-stage throttling cooling thermodynamic cycle, and is the theoretical limit of the refrigeration cycle energy efficiency. When the number of compression stages approaches infinity, the compression ratio of each stage approaches 1, the throttling cooling process is infinitely subdivided, and the cycle is close to a reversible process. At this time, the refrigeration energy efficiency is only determined by the saturation temperature of the evaporator and condenser (regardless of the number of compressor stages and the actual operating efficiency), representing the highest energy efficiency level that can be achieved by this thermodynamic cycle (determined by the evaporation temperature and condensation temperature). The ideal isentropic compression refrigeration energy efficiency serves as the "benchmark upper limit" for evaluating actual cycle performance, and is used to measure the gap between the actual multi-stage system and the ideal state. Multi-stage compression work coefficient It refers to the ratio of the isentropic compression work ratio of n-stage compression to the isentropic compression work ratio of infinite-stage compression. It can be used to quantify the "degree to which the compression work is close to the ideal minimum value" under the actual number of 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 infinite stages, and the smaller the energy loss in the compression process. It can directly reflect the contribution of the number of compression stages to "reducing energy consumption" and guide the design of the number of stages (for example, the document shows that the coefficient is close to 1 after two-stage compression, and the improvement is limited by increasing the number of stages). Multi-stage refrigeration capacity coefficient It 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 the "degree of cooling capacity close to the ideal maximum" under the actual 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 change of this coefficient is very small (for example, there is only a slight increase of 1.4% from single stage to 5 stages), which shows that the impact of the number of stages on cooling capacity is limited, and it is clear that the core value of multi-stage compression is "reducing energy consumption" rather than "increasing cooling capacity". Isentropic compression efficiency Refers to the efficiency of the actual compression process of the compressor. It can exclude external factors such as the temperature of the chilled water / cooling water (thermodynamic cycle) and the efficiency of auxiliary equipment, and only reflects the energy conversion efficiency of the compressor's own compression process (i.e., the ratio of actual compression work to theoretical isentropic compression work). Achieving a horizontal comparison of compressor performance under different stages and different operating conditions (such as the efficiency comparison of single-stage and two-stage compression under the same load) is a core indicator for evaluating the quality of compressor design. Isentropic compression refrigeration energy efficiency This 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 cooling capacity coefficient, and the multi-stage compression work coefficient. It is unrelated to the actual operating efficiency of the compressor (which is dependent only on the number of stages and thermodynamic cycle parameters). It can be used as an intermediate parameter in calculating isentropic compression efficiency, linking actual COP with theoretical cycle energy efficiency, and quantifying the impact of the number of stages on the cycle's inherent energy efficiency.

[0057] In one implementation of this embodiment, the COP of the refrigerator can be expressed as formula (13): (13); In formula (13), is the cooling capacity per unit refrigerant mass in the evaporator, i.e. specific cooling capacity, kJ / kg; The total input electrical work per unit refrigerant mass, i.e. specific work, is expressed in kJ / kg. The unit refrigerant mass here refers to the intake air volume of the final stage of compression.

[0058] For n-stage compression refrigeration, its cooling capacity is the specific cooling capacity of the evaporator before the first stage compression. , where the refrigerant quality is still based on the final stage compression intake volume, which can be expressed as formula (14): (14); Formula (13) can also be expressed as formula (15): (15); Or it can be expressed as formula (16): (16); Among them, the ideal isentropic compression refrigeration energy efficiency, multi-stage compression work coefficient, multi-stage refrigeration capacity coefficient and isentropic compression efficiency are defined by formulas (17) to (20): (17); (18); (19); (20); In formula (17) ~ formula (20), Ideal isentropic compression refrigeration energy efficiency for infinite-stage isentropic compression and infinite-stage throttling cooling; and are the ideal specific cooling capacity and specific isentropic compression work of the multi-stage isentropic compression and multi-stage throttling cooling cycle, kJ / kg respectively; is the specific work of multi-stage isentropic compression, kJ / kg; is the actual specific work of multi-stage compression, kJ / kg; The refrigeration coefficient of the multi-stage compression and multi-stage throttling cooling cycle; is the compression work coefficient of the multi-stage compression and multi-stage throttling cooling cycle; The isentropic compression efficiency of the compressor in a multi-stage compression and multi-stage throttling cooling cycle.

[0059] At the same time, from the electrical power input to the compressor shaft power output, it can be expressed as formula (21): (twenty one); In formula (21), 、 、 The following are the efficiencies of the inverter, motor, and mechanical transmission equipment respectively.

[0060] Defining the energy efficiency of multi-stage isentropic compression refrigeration Formula (22): (twenty two); In formula (22), is the isentropic compression refrigeration efficiency of a refrigerator with n-stage compression, n-stage throttling and n-1-stage cooling cycle. When n→∞, →1 and →1, so we have → .

[0061] In formula (16), It is an ideal isentropic compression refrigeration efficiency with infinite stage isentropic compression and infinite stage throttling cooling. It has nothing to do with the total number of compressor stages and only depends on the saturation temperature of the evaporator and condenser. Depends on the evaporator specific cooling capacity , which 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 compression stages and the thermodynamic cycle characteristics determined by the saturation temperature of the evaporator and condenser, and has nothing to do with the actual operating conditions of the compressor.

[0062] According to formula (22), the multi-stage isentropic compression efficiency of the compressor can be expressed as formula (23): (twenty three); According to the definition of formula (20), the isentropic compression efficiency of the compressor is It depends on the actual compression ratio work of the compressor and the isentropic compression ratio work of multi-stage compression. Expressed in another form, formula (23) shows that the isentropic compression efficiency of the compressor can be obtained by the actual COP of the refrigerator, the saturation temperature of the evaporator and condenser, the total number of compression stages of the compressor, as well as the efficiency of the inverter, the efficiency of the motor, the efficiency of the mechanical transmission, and other parameters.

[0063] The COP of the refrigerator expressed in formula (16) can be divided into three influencing factors. One is the refrigeration system parameters, including refrigeration temperature and cooling temperature, which mainly affect the ideal isentropic compression cycle. , is the inherent performance parameter of the thermodynamic cycle; one is related to the total number of compression stages of the compressor, which mainly affects the refrigeration coefficient Compression work coefficient The third type is related to the actual compression work, that is, the isentropic compression efficiency of the compressor. This parameter can reflect the actual operating efficiency performance of the compressor. It can be compared horizontally for different refrigeration conditions and different total number of compressor stages, and can be used for design and operation analysis.

[0064] For multi-stage isentropic compression specific work, it can be expressed as formula (24): (twenty four); In formula (24), is the isentropic compression work of n-stage compression, kJ / kg; is the isentropic compression work of the i-th stage, kJ / kg. When n→∞, → Formula (24) can also be expressed as Formula (25): (25); In formula (24), Represents the condensation amount of the condenser refrigerant, kg, that is, formula (26): (26); For multi-stage compression ratio refrigeration capacity, it can be expressed as formula (27): (27); Or it can be expressed as formula (28): (28); When n→∞, → .

[0065] Under the conditions of known evaporator saturation temperature and condenser saturation temperature (or evaporator saturation pressure and condenser saturation pressure), and the total number of compression stages n of the compressor, according to formula (1), formula (4), formula (6) to formula (12), formula (16) to formula (22), 、 、 、 、 Process variables such as refrigeration and compressor performance coefficients can be obtained 、 、 、 According to the actual COP of the refrigerator, as well as the inverter efficiency, motor efficiency, mechanical transmission efficiency and other parameters, the isentropic compression efficiency of the compressor is obtained by formula (23): This embodiment uses R134a refrigerant for analysis, and the isentropic compression exhaust temperature can be solved by combining the thermophysical property equations such as formula (7) to formula (9) and formula (11) and formula (10) to formula (12).

[0066] This embodiment constructs a mathematical model that fully describes the thermodynamic behavior of the compressor under specific preset conditions. It also quantitatively evaluates its performance through primary performance parameters, laying the foundation for subsequent parameter fitting and comparative analysis. Its core lies in transforming the physical description of the cycle process into a computable mathematical relationship. All parameters are derived based on existing performance parameters, ensuring the model's objectivity and verifiability.

[0067] In some embodiments, the thermophysical property parameters include saturation pressure, saturation temperature, saturated liquid specific enthalpy, saturated gas specific enthalpy, superheated steam specific enthalpy and superheated steam specific entropy, and 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 energy efficiency, multi-stage compression work coefficient, multi-stage refrigeration capacity coefficient, isentropic compression efficiency and isentropic compression refrigeration energy efficiency. The multiple second performance parameters include exhaust temperature, multi-stage isentropic compression specific work, multi-stage isentropic compression specific refrigeration capacity and compression intake volume of each stage.

[0068] Step S300 may include but is not limited to steps S310 to S380: For each of the preset conditions, the following processing is performed: Step S310, fitting the saturation pressure, the saturation 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 specific work, the value of the multi-stage isentropic compression specific cooling capacity, and the value of the compression intake volume of each stage; Step S320, taking the difference between the saturated liquid specific enthalpy and the saturated gas specific enthalpy as the value of the ideal specific cooling capacity; Step S330, taking the integral of the specific enthalpy difference from the evaporator pressure to the condenser pressure of the compressor as the value of the specific isentropic compression work; Step S340, taking the ratio of the ideal specific cooling capacity to the specific isentropic compression work as the ideal isentropic compression refrigeration energy efficiency; Step S350, taking the ratio of the multi-stage isentropic compression ratio cooling capacity to the ideal ratio cooling capacity as the multi-stage cooling capacity coefficient; Step S360, taking the ratio of the value of the isentropic compression work ratio to the value of the multi-stage isentropic compression work ratio as the value of the multi-stage compression work coefficient; Step S370, taking the ratio of the multi-stage isentropic compression specific work value to the actual specific work value as the isentropic compression efficiency value; Step S380: Obtain the value of the isentropic compression refrigeration energy efficiency according to 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.

[0069] In this embodiment, the specific values ​​of multiple target performance parameters are obtained by fitting a mathematical model of the compressor under preset conditions to the thermophysical properties of the refrigerant. These parameters include secondary performance parameters such as exhaust temperature, specific work, specific cooling capacity, and intake air volume at each stage of compression, 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.

[0070] Specifically, saturation pressure refers to the pressure when the refrigerant is in gas-liquid equilibrium at a given temperature; saturation temperature refers to the temperature when the refrigerant is in gas-liquid equilibrium at a given pressure; saturated liquid specific enthalpy refers to the enthalpy value of unit mass of saturated liquid refrigerant; saturated gas specific enthalpy refers to the enthalpy value of unit mass of saturated gaseous refrigerant; superheated steam specific enthalpy refers to the enthalpy value of unit mass of superheated steam; superheated steam specific entropy refers to the entropy value of unit mass of superheated steam.

[0071] Thermophysical property parameters were fitted to the mathematical model for each preset condition. The final stage exhaust temperature was inferred by using the conservation of specific entropy during the isentropic compression process (Equation 10) and the fitting formula for superheated steam specific entropy, temperature, and pressure. The specific enthalpy difference for each isentropic compression stage was calculated, combined with the intake volume ratio of each stage (corrected for throttling effects), and the weighted summation was used to determine the total specific work.

[0072] In one implementation of this embodiment, taking R134a refrigerant (applicable range: -10°C~60°C, 200kPa~1000kPa) as an example, the following thermophysical property equation is obtained by fitting.

[0073] Saturation temperature , ℃, and pressure , kPa, is shown in formula (29): (29); 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 are all constants.

[0074] The fitting coefficients of the relationship between saturation temperature and pressure are shown in Table 1: Table 1

[0075] Saturation pressure , kPa, and saturation temperature , ℃, is shown in formula (30): (30); The fitting coefficients of the relationship between saturation pressure and saturation temperature are shown in Table 2: Table 2

[0076] Saturated liquid specific enthalpy , kJ / kg, and saturation temperature , ℃, is shown in formula (31): (31); The fitting coefficient of the relationship between saturated liquid specific enthalpy and saturation temperature is shown in Table 3: Table 3

[0077] Saturated gas specific enthalpy , kJ / kg, and saturation temperature , ℃, is shown in formula (32): (32); The fitting coefficients of the relationship between saturated gas specific enthalpy and saturation temperature are shown in Table 4: Table 4

[0078] Gas specific enthalpy , kJ / kg, and pressure , kPa, and temperature , ℃, is shown in formula (33): (33); 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 are all constants.

[0079] The fitting coefficients of the relationship between superheated steam specific enthalpy, pressure and temperature are shown in Table 5: Table 5

[0080] Gas specific entropy , kJ / kg, and pressure , kPa, and temperature , ℃, are shown in formula (34) to formula (37): (34); (35); (36); (37); 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 are all constants.

[0081] The fitting coefficients of the relationship between superheated steam specific entropy, pressure and temperature are shown in Table 6: Table 6

[0082] According to formula (10) to formula (12), the exhaust temperature of the i-th stage isentropic compression is calculated. When , according to formula (38) to formula (39): (38); (39); Solving formula (40): (40); Substituting the thermophysical parameters into the mathematical model (including the pressure ratio equations of each stage, the energy balance equation, etc.), the values ​​of the exhaust temperature, the multi-stage isentropic compression specific work, the multi-stage isentropic compression specific cooling capacity, and the values ​​of the compression intake volume of each stage are fitted. Specifically, according to formulas (10) to (12) and (38) to (40), the isentropic compression exhaust temperature of the i-th stage isentropic compression is calculated by the conservation of specific entropy of the isentropic compression process and 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 saturated liquid specific enthalpy and the saturated gas specific enthalpy through the throttling energy balance equation, and then the specific value of the intake volume of each stage is obtained; according to formula (24), the multi-stage isentropic compression specific work is calculated; according to formulas (27) to (28), 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, the multi-stage isentropic compression specific cooling capacity is calculated.

[0083] Furthermore, the ideal specific cooling capacity is calculated based on the difference between the specific enthalpy of the saturated liquid state and the specific enthalpy of the saturated gas state. The ideal specific cooling capacity is the heat absorbed by a unit mass of refrigerant in the evaporator when it changes from a saturated liquid to a saturated gas state. It is determined solely by the saturation state parameters of the evaporator and is independent of the number of compression stages. During 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 of the ideal isentropic compression process and can be calculated by integrating the specific enthalpy difference of the compressor from the evaporator pressure to the condenser pressure. 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 the theoretical minimum. The ideal isentropic compression refrigeration energy efficiency is the ratio of the ideal specific cooling 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 multi-stage cooling capacity coefficient measures how close the actual specific cooling capacity is to the ideal value. It is the ratio of the multi-stage isentropic compression specific cooling capacity to the ideal specific cooling capacity, and is used to reflect the weight of each stage's cooling capacity in the total cooling capacity. The multi-stage compression work coefficient is the ratio of the specific isentropic compression work to the multi-stage isentropic compression specific work, and is used to quantify the contribution of each stage's compression work to the total work. The isentropic compression efficiency is the ratio of the multi-stage isentropic compression specific work to the actual specific work, where the actual specific work refers to the actual input specific work of the compressor and can be calculated by combining the 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 multi-stage compression work coefficient, and the multi-stage cooling capacity coefficient, and reflects the ideal energy efficiency of the thermodynamic cycle under a specific number of compression stages.

[0084] This embodiment first calculates secondary performance parameters such as exhaust temperature and intake volume at each stage by fitting thermophysical property parameters with a mathematical model. Then, combined with thermodynamic calculations such as enthalpy difference and integration in an ideal cycle, various efficiencies and coefficients in the multi-stage compression system are derived, ultimately obtaining 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 operational performance improvement.

[0085] In some embodiments, step S400 may include but is not limited to steps S410 to S420: Step S410: for each of the preset conditions, obtaining values ​​of a plurality of target performance parameters of the compressor under the preset condition; Step S420, compare and evaluate the total number of compression stages corresponding to each of the preset conditions and the value of each target performance parameter under the refrigeration condition corresponding to each of the preset conditions to obtain the evaluation result, which indicates the impact of the total number of compression stages and the refrigeration condition on each of the multiple performance parameters.

[0086] In this embodiment, for each preset condition (i.e., a specific combination of the total number of compression stages and the refrigeration operating conditions), the specific values ​​of all the target performance parameters obtained by calculation are collected, and then a comparative analysis is performed on the impact of the total number of compression stages on each performance parameter and the impact of the refrigeration operating conditions on each performance parameter.

[0087] Specifically, step S420 may include but is not limited to steps S421 to S424: Step S421, comparing and evaluating the exhaust temperature, the multi-stage isentropic compression specific work, the multi-stage isentropic compression specific cooling capacity, and the values ​​of the compressed air intake volume at each stage corresponding to each total number of compression stages, to obtain a first evaluation result, wherein the first evaluation result includes a change trend of the exhaust temperature value, a change trend of the specific work value, a change trend of the specific cooling capacity value, and a change trend of the compressed air intake volume at each stage as the total number of compression stages increases; Step S422: Compare and evaluate the values ​​of the ideal isentropic compression refrigeration energy efficiency, the values ​​of the multi-stage compression work coefficient, the values ​​of the multi-stage cooling capacity coefficient, and the values ​​of the isentropic compression refrigeration energy efficiency under each total number of compression stages and each refrigeration operating condition to obtain a second evaluation result, wherein the second evaluation result includes a change trend of the value of the ideal isentropic compression refrigeration energy efficiency, a change trend of the value of the multi-stage compression work coefficient, a change trend of the value of the multi-stage cooling capacity coefficient, and a change trend of the value of the isentropic compression refrigeration energy efficiency as the total number of compression stages increases; Step S423, obtaining a third evaluation result based on the change trend of the ideal isentropic compression refrigeration energy efficiency value of the compressor under different refrigeration conditions, the change trend of the multi-stage compression work coefficient value, the change trend of the multi-stage cooling capacity coefficient value, and the change trend of the isentropic compression refrigeration energy efficiency value; Step S424: Obtain the evaluation result according to the first evaluation result, the second evaluation result, and the third evaluation result.

[0088] In this embodiment, the values ​​of the exhaust temperature, multi-stage isentropic compression specific work, multi-stage isentropic compression specific cooling capacity, and compression intake volume for each stage are first compared for each total number of compression stages. The changing trends of the exhaust temperature, specific work, specific cooling capacity, and compression intake volume for each stage are analyzed as the total number of compression stages increases, yielding a first evaluation result. Secondly, the values ​​of the ideal isentropic compression refrigeration efficiency, multi-stage compression work coefficient, multi-stage cooling capacity coefficient, and isentropic compression refrigeration efficiency for each total number of compression stages and each refrigeration condition are compared. The changing trends of the ideal isentropic compression refrigeration efficiency, multi-stage compression work coefficient, multi-stage cooling capacity coefficient, and isentropic compression refrigeration efficiency for each total number of compression stages and each refrigeration condition are analyzed as the total number of compression stages increases, yielding a second evaluation result. Furthermore, the changing trends of the ideal isentropic compression refrigeration efficiency, multi-stage compression work coefficient, multi-stage cooling capacity coefficient, and isentropic compression refrigeration efficiency for each refrigeration condition are analyzed, yielding a third evaluation result.

[0089] Specifically, according to the mathematical model, the multi-stage isentropic compression and multi-stage throttling cooling cycle process is calculated. Figure 4 The temperature entropy diagram of each stage of intake and final stage exhaust states in single-stage isentropic compression and 5-stage isentropic compression with 4-stage throttling cooling process. Figure 4 It can be seen that for the 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 isentropic compression of the previous stage, so the specific entropy of the intake air of each stage gradually decreases. Taking R134a refrigerant as an example, for Figure 4 As shown in the 5-stage isentropic compression, 5-stage throttling and 4-stage intermediate cooling process, the evaporation temperature is -6.6℃, the condensation temperature is 35℃, and the exhaust temperature of the final compression stage is 38.9℃, which is 0.7℃ lower than the exhaust temperature of the single-stage isentropic compression of 39.6℃. The exhaust temperature has a certain decrease, but the decrease is not large. This is related to the thermal properties of R134a. Figure 2 It can be seen that the saturation temperature of the gas phase saturation line of R134a changes steeply with the specific entropy, or in other words, the range of change of specific entropy is small at different saturation temperatures. Therefore, after each stage of isentropic compression, the temperature is limited by mixing with the throttling saturated steam, resulting in a small drop in exhaust temperature after multi-stage isentropic compression and multi-stage cooling.

[0090] Figure 5 It shows the change of the exhaust temperature of the final stage of the compressor with different compression stages, and the change of the evaporation ratio of the evaporator refrigerant. Figure 5 It can be seen that as the total number of compression stages of the compressor increases, the exhaust temperature of the final stage of the compressor gradually decreases. From 2-stage compression to 5-stage compression, the exhaust temperature of the final stage changes very little. It can be considered that the exhaust temperature of the final stage of 5-stage compression is close to the exhaust temperature of the final stage of infinite-stage compression. In subsequent analysis, the parameters of 5-stage compression are equivalent to the parameters of infinite-stage compression. Figure 5 It can also be seen that when using R134a refrigerant, for models with different total number of compressor stages, the total number of compressor stages has little effect on the exhaust temperature of the final isentropic compression stage.

[0091] Depend on Figure 5 It can also be seen that from single-stage compression to 5-stage compression, the evaporation ratio of the evaporator increases from 71.5% to 72.9%, and the change is not large. This shows that for the refrigerator using R134a refrigerant, the specific cooling capacity of the multi-stage compression cycle and the single-stage compression cycle does not change much, and the multi-stage compression has little effect on the cooling capacity of the refrigerant.

[0092] Figure 6 For compressors with different total compression stages, the change in the ratio of intake air volume at each stage. Figure 6 It can be seen that as the total number of compressor stages increases, the intake volume for the same i-th stage of compression decreases. For example, for the second stage of compression, the intake volume ratio is 100%; for the third stage of compression, the intake volume ratio is 87.8%; and for the fifth stage of compression, the intake volume ratio is 80.9%. This shows that the advantage of multi-stage compression and multi-stage throttling cooling is that the increase in the total number of compressor stages reduces the intake volume of each stage of compression, thereby reducing the total compression work.

[0093] Figure 7 It shows the changes of multi-stage compression, multi-stage throttling cooling, isentropic compression specific work and specific cooling capacity. Figure 7 It can be seen that with Figure 6 Correspondingly, as the total number of compressor stages increases, the isentropic compression work ratio gradually decreases. For the working conditions of evaporation temperature -6.6℃ and condensation temperature 35℃, it decreases from 28.2kJ / kg of single-stage compression to 24.5kJ / kg, a decrease of 13.1%, indicating that the advantage of multi-stage compression is reflected in the reduction of compression work. At the same time, the reduction in compression work ratio from 2-stage compression to 5-stage compression is not large. Figure 7 It can also be seen that for refrigerators with different total compression stages, the specific cooling capacity does not change much, and Figure 5 The evaporation ratio of the evaporator corresponds to the evaporation ratio of the evaporator.

[0094] Figure 7The paper analyzed three typical cooling conditions: ice storage (evaporating temperature -6.6°C, condensing temperature 35°C), building air conditioning (evaporating temperature 6°C, condensing temperature 38°C), and data center cooling (evaporating temperature 14°C, condensing temperature 38°C). The results were essentially consistent across all three conditions, with the total number of stages having little impact on cooling capacity. Specific compression work decreased with increasing the number of compression stages, but the change was limited after two stages. For ice storage, the change in specific compression work from one to two stages was more pronounced. This suggests that for multi-stage compressors using R134a refrigerant, two stages already effectively utilize the compression work reduction advantage of multi-stage compression, and increasing the total number of compressor stages has little effect.

[0095] according to Figure 8 The results in the above table can be used to obtain the isentropic compression cycle refrigeration of compressors with different compression stages. .Depend on Figure 8 It can be seen that as the total number of compressor stages increases, the refrigerator It increases gradually. When the total number of compressor stages reaches 5, the increase tends to be gentle. It can be considered that when the 5-stage compression is completed, it is close to the isentropic compression of infinite-stage compression. In ice storage conditions, from single-stage compression to double-stage compression, 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 the third stage of compression, increasing the total number of compressor stages has an impact on the isentropic compression of the refrigerator. In air conditioning and data center cooling conditions, the COP of isentropic compression increases by 8.3% and 9.2% from single-stage compression to two-stage compression, and the COP of isentropic compression cycle increases by 8.3% and 9.2% from two-stage compression to five-stage compression. The increases were 4.4% and 5.7% respectively. Increasing the number of compressor stages had a significant impact on the isentropic compression performance of the refrigerator. The improvement effect is not obvious.

[0096] According to formula (19), for a certain evaporation temperature and condensation temperature, the compression work coefficient is It depends on the number of compressor stages and is an inherent performance parameter that has nothing to do with the actual operation of the compressor. Figure 9 Expressed As the total number of compression stages of the compressor changes, Figure 9 Three typical operating conditions are shown in Figure 1, including ice storage, air conditioning, and data center cooling. Figure 9 It can be seen from the figure that the compression power coefficient increases with the increase of the number of compressor stages, and its increase is Figure 7The 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 The compression work coefficient and refrigeration coefficient The comprehensive impact on refrigeration performance can be seen. Change curve and The change curves are close, indicating that for compressors with different numbers of stages, It has little effect on the performance of the refrigerator.

[0097] Isentropic compression refrigeration It is an inherent characteristic of the refrigerator and has nothing to do with the actual operating performance of the compressor. Depends on the saturation temperature of the evaporator and condenser, combined with the cooling capacity coefficient and compression work coefficient of different compression stages, for single-stage compression, two-stage compression and three-stage compression three types of compressors, and three refrigeration temperature conditions, isentropic compression refrigeration The curve of condensation temperature is as follows Figure 10 As shown. For the same refrigeration temperature condition, the influence of the three compressor stages is relatively small, while the refrigeration temperature has a relatively small influence on the isentropic compression refrigeration. For all working conditions, as the condensing temperature increases, the isentropic compression refrigeration Decrease. Figure 10 It can be seen that the cooling temperature and the condensing temperature have a great influence on the isentropic compression refrigeration of the refrigerator. The influence of the number of compressor stages is far greater than that of the compressor stages. It can be considered that in a certain range of refrigeration temperature and cooling temperature, reasonable operation of refrigeration system parameters can improve the isentropic compression refrigeration. , is just as important as choosing the number of compressor stages.

[0098] In this embodiment, the first evaluation results include: as the total number of compression stages increases, the exhaust temperature of the last stage of the compressor 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 increases slightly, but the change range is small; as the total number of compression stages increases, the proportion of compressed intake volume of the same stage gradually decreases.

[0099] The second evaluation results include: the ideal isentropic compression refrigeration energy efficiency is determined only by the saturation temperatures of the evaporator and condenser, and is not related to the total number of compression stages; as the total number of compression stages increases, the multi-stage compression work coefficient gradually increases and approaches 1; as the total number of compression stages increases, the multi-stage cooling capacity coefficient increases slightly and approaches 1; as the total number of compression stages increases, the isentropic compression refrigeration energy efficiency gradually increases and approaches the ideal isentropic compression refrigeration energy efficiency.

[0100] The third evaluation results include: the ideal isentropic compression refrigeration energy efficiency increases significantly with increasing evaporation temperature or decreasing condensing temperature; the multi-stage compression work coefficient is less affected by the refrigeration conditions, the compression work coefficient mainly depends on the number of stages and has a weak correlation with the operating conditions; the multi-stage cooling capacity coefficient is extremely small affected by the refrigeration conditions; the changing trend of the isentropic compression refrigeration energy efficiency is consistent with the ideal isentropic compression refrigeration energy efficiency, that is, it increases with increasing evaporation temperature or decreasing condensing temperature, and increases with increasing number of stages under the same operating conditions.

[0101] Based on the first, second, and third evaluation results, the impact of the total number of compression stages and refrigeration operating conditions on performance parameters was comprehensively determined, forming the evaluation results. The impact of the total number of compression stages is as follows: Low-stage compression (1-2) significantly reduces exhaust temperature and specific work, improving isentropic compression efficiency and making it the most cost-effective optimization method. The optimization effect of high-stage compression (2-5) slows down, with 5-stage compression approaching the theoretical limit of infinite-stage compression, and further increasing the number of stages has limited performance improvement. The total number of compression stages significantly affects the airflow distribution between each stage, but has a smaller impact on the relative cooling capacity. The impact of refrigeration operating conditions is as follows: evaporation temperature and condensing temperature are the core factors determining the ideal isentropic compression efficiency, with their influence far greater than the total number of compression stages. Isentropic compression efficiency increases significantly with increasing evaporation temperature or decreasing condensing temperature. Optimizing operating parameters (such as lowering the condensing temperature) can improve actual efficiency more than increasing the number of compression stages. The work coefficient and cooling capacity coefficient of multi-stage compression are less affected by operating conditions and are primarily determined by the total number of compression stages.

[0102] This example analyzes the impact of the total number of compression stages and refrigeration conditions on various performance parameters, revealing how compressor performance changes with these factors. This systematic analysis approach facilitates a deeper understanding of compressor performance characteristics, providing a scientific basis for compressor design optimization and operating parameter selection. Furthermore, through comprehensive analysis of multiple target performance parameters, the limitations of single-metric evaluation are avoided, resulting in more comprehensive and accurate performance evaluation results.

[0103] In some embodiments, step S400 may further include but is not limited to steps S500 to S600: Step S500, obtaining the value of the isentropic compression efficiency of the compressor under each of the preset conditions; Step S600, comparative analysis is performed on the total number of compression stages corresponding to each of the preset conditions and the values ​​of the isentropic compression efficiency under the refrigeration conditions corresponding to each of the preset conditions, and the total number of compression stages and the refrigeration conditions corresponding to the maximum value of the isentropic compression efficiency are used as the target total number of compression stages and the target conditions of the compressor.

[0104] In this embodiment, after a performance comparison evaluation is performed on the values ​​of multiple target performance parameters of the compressor under each preset condition and the evaluation results are obtained, the value of 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. The higher its value, the higher the operating efficiency of the compressor. The isentropic compression efficiency values ​​under different total compression stages are compared, and the influence of the total compression stage on the isentropic compression efficiency is analyzed. The isentropic compression efficiency values ​​under different refrigeration conditions are compared, and the influence of the refrigeration conditions on the isentropic compression efficiency is analyzed. The interactive influence of the total compression stage and the refrigeration conditions on the isentropic compression efficiency is comprehensively analyzed. The total compression stage and the refrigeration condition corresponding to the maximum value of the isentropic compression efficiency are used as the target total compression stage and target condition of the compressor. The target total compression stage and target condition are the configurations with the best operating efficiency of the compressor under current conditions, which can provide a basis for the design, selection and operation optimization of the compressor.

[0105] Specifically, based on an 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 chiller performance under different operating conditions. IPLV (Integrated Part Load Value) is the integrated part load performance coefficient, which is a single value representing the part load efficiency of an air conditioning chiller, calculated by weighting the unit's coefficient of performance at part load, calculated according to the cumulative load percentage of the unit under various load conditions. NPLV (Nonstandard Part Load Value) is the standardized part load value, primarily used in atypical cooling tower applications or where cooling water temperatures do not meet standard requirements. It takes into account equipment performance under nonstandard water temperature conditions and calculates energy efficiency values ​​using adjusted temperature conditions to provide a more accurate performance assessment under nonstandard conditions.

[0106] Table 7 shows the COP values ​​of two models of centrifugal refrigerators under different load rate conditions, including four refrigeration load rate conditions. Among them, refrigerator A is a variable frequency two-stage compression centrifugal refrigerator, and refrigerator B is a variable frequency magnetic levitation single-stage compression centrifugal refrigerator.

[0107] Table 7

[0108] Generally speaking, the inverter efficiency is 97.0~98.0%, AC motor About 95.0%, the efficiency of magnetic bearing The rolling bearing efficiency is 98.0~99.8%. 95.0~99.5%. 97.5%, AC motor 95.0%, magnetic bearing 98.9%, rolling bearings It is 97.3%.

[0109] According to formula (23), the isentropic compression efficiency of the compressor under the corresponding working condition can be obtained: It can be seen from Table 7 that for the two-stage compression refrigerator A, its maximum isentropic compression efficiency is 2 appears at the 100% load factor design condition. The isentropic compression efficiency at 75% and 50% load factors is also greater than 80%, close to the isentropic compression efficiency at 100% load factor. At 25% load factor, the isentropic compression efficiency drops significantly. This shows that this type of chiller should avoid operating at low loads as much as possible.

[0110] For a single-stage compression refrigerator B, the maximum isentropic compression efficiency 1 also appears at the design condition of 100% load rate. The isentropic compression efficiency at 75% and 50% load rates is also relatively high. The isentropic compression efficiency at 25% load rate is the same as that of model A refrigerator, and the efficiency decreases significantly.

[0111] It should be noted that the isentropic compression efficiency of single-stage compression is 1 with two-stage compression 2, only represents the isentropic compression efficiency of the compressor. If the refrigeration COP of the refrigerator is evaluated, the compression work coefficient and the refrigeration coefficient must be considered comprehensively. For example, as shown in Table 7, at 100% load rate, although the single-stage compression 1 is 92.2%, higher than double-stage compression 85.1% of 2, but with double-stage compression 2 is 8.67, single-stage compression 1 is 7.21, so the COP of two-stage refrigeration is 6.64, which is greater than the COP of single-stage refrigeration is 6.09. Therefore, it is necessary to comprehensively consider the impact of the compressor isentropic compression coefficient and the number of compression stages on the performance of the refrigerator.

[0112] In summary, the isentropic compression efficiency of the compressor By separating it from the complex factors affecting the performance of the refrigerator, shielding the influence of the refrigerant environmental parameters on the thermodynamic cycle performance of the refrigerator, and only considering the actual operating performance of the compressor, the universality of the compressor operating performance evaluation can be greatly improved, and it can be conveniently used in the design and operation analysis of refrigeration centrifugal compressors.

[0113] This embodiment uses isentropic compression efficiency to comprehensively compare and evaluate compressor performance under different compression stages and operating conditions, thereby determining the optimal operating parameters for the compressor. This avoids the limitations of relying solely on experience or local indicators for model selection, provides an objective basis for compressor design optimization and rational selection, and helps improve the overall performance and operating efficiency of the compressor.

[0114] The embodiment of the present application proposes definitions such as the ideal refrigeration COP, multi-stage compression work coefficient, multi-stage refrigeration capacity coefficient, isentropic compression efficiency of the multi-stage compression multi-stage throttling cooling compressor, and refrigeration COP of the multi-stage compression multi-stage throttling cooling thermodynamic cycle for analyzing the efficiency of refrigerators and compressors and establishing corresponding mathematical models; the thermophysical properties of the refrigerant R134a refrigerant are fitted, and the fitting formula can accurately represent the relationship between the specific entropy of superheated steam and the temperature and pressure; by establishing a mathematical model, the performance of the compressor is analyzed, including the exhaust temperature, specific work, specific refrigeration capacity, and intake volume of each stage of the multi-stage compression multi-stage throttling cooling compressor, as well as the ideal refrigeration COP, multi-stage compression work coefficient, multi-stage refrigeration capacity coefficient, and refrigeration CO of the infinite-stage compression infinite-stage throttling cooling thermodynamic cycle. The newly proposed refrigerator and compressor parameters such as COP, multi-stage compression, multi-stage throttling cooling compressor isentropic compression efficiency are analyzed to study the influence of different total compression stages of compressors; based on the COP data of the refrigerator, according to the mathematical model, the isentropic compression efficiency of the compressors of single-stage compression and two-stage compression refrigerators is obtained, and compressors with different compression stages can be compared horizontally, and different operating conditions of the same compressor can be compared; the factors of thermodynamic cycle efficiency (chilled water temperature and cooling water temperature) that affect the COP performance of the refrigerator are separated, and the compression efficiency of the compressor is obtained according to the COP of the refrigerator; the embodiment of the present application is universal for evaluating the compression efficiency of compressors with multi-stage compression, multi-stage throttling cooling, and provides a performance analysis method for analyzing centrifugal refrigeration compressors with multi-stage compression, multi-stage throttling cooling, which is a powerful tool for the design, selection and operation analysis and optimization of refrigeration compressors.

[0115] See also Figure 11 The present application also provides a compressor performance evaluation device 700, which can implement the above-mentioned compressor performance evaluation method. The device includes: A first constructing module 10 is configured to construct a thermodynamic cycle flow of the compressor under a plurality of preset conditions based on the compression process of the compressor under each of the preset conditions, wherein the preset conditions include at least one of a total number of compression stages and a refrigeration operating condition, and the refrigeration operating condition corresponds to an evaporation temperature and a condensation temperature; A second building module 20 is configured to build, for each of the preset conditions, a mathematical model of the compressor under the preset conditions based on the thermodynamic cycle process of the compressor under the preset conditions, wherein the mathematical model includes a plurality of target performance parameters for evaluating the performance of the compressor; A fitting module 30 is configured to fit the mathematical model of the compressor under the preset conditions with the thermophysical property parameters of the refrigerant of the compressor to obtain a value of each target performance parameter of the compressor under the preset conditions; The evaluation module 40 is configured to perform a performance comparison evaluation on the values ​​of the plurality of target performance parameters of the compressor under each of the preset conditions to obtain an evaluation result.

[0116] In some embodiments, the first building block 10 may include: The first construction submodule is used to decompose the compression process into multiple isentropic compression stages for each of the preset conditions according to the total number of compression stages of the compressor under the preset conditions, and introduce a throttling cooling process between each isentropic compression stage to construct the thermodynamic cycle process.

[0117] In some embodiments, the second building block 20 may include: a first acquisition submodule, configured to acquire, for each of the preset conditions, a plurality of first performance parameters of the compressor under the preset condition, where the first performance parameters are calculated based on existing performance parameters of the compressor; The second construction submodule is configured to construct the mathematical model of the compressor under the preset conditions based on the thermodynamic cycle process and a plurality of the first performance parameters.

[0118] In some embodiments, the fitting module 30 may include: a fitting submodule for performing the following processing for each of the preset conditions: the thermophysical property 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 energy efficiency, multi-stage compression work coefficient, multi-stage cooling capacity coefficient, isentropic compression efficiency, and isentropic compression refrigeration energy efficiency; the multiple second performance parameters include exhaust temperature, multi-stage isentropic compression specific work, multi-stage isentropic compression specific cooling capacity, and each stage compression intake volume; fitting the saturation pressure, the saturation 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 specific work, the value of the multi-stage isentropic compression specific cooling capacity, and the value of the compression intake volume at each stage; A first calculation submodule is configured to use the difference between the saturated liquid specific enthalpy and the saturated gas specific enthalpy as a value of an ideal specific cooling capacity; A second calculation submodule is configured to use the integral of the specific enthalpy difference from the evaporator pressure to the condenser pressure of the compressor as the value of the specific isentropic compression work; a third calculation submodule, configured to use a ratio of the ideal specific cooling capacity to the specific isentropic compression work as the ideal isentropic compression refrigeration energy efficiency; A fourth calculation submodule is configured to use a ratio of the multi-stage isentropic compression ratio cooling capacity to the ideal ratio cooling capacity as a value of the multi-stage cooling capacity coefficient; a fifth calculation submodule, configured to use a ratio of the value of the isentropic compression work ratio to the value of the multi-stage isentropic compression work ratio as a value of the multi-stage compression work coefficient; a sixth calculation submodule, configured to use the ratio of the value of the multi-stage isentropic compression specific work to the actual specific work as the value of the isentropic compression efficiency; The seventh calculation submodule is used to obtain the value of the isentropic compression refrigeration energy efficiency according to 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.

[0119] In some embodiments, the assessment module 40 may include: a second acquisition submodule, configured to acquire, for each of the preset conditions, values ​​of a plurality of target performance parameters of the compressor under the preset condition; An evaluation submodule is used to compare and evaluate the total number of compression stages corresponding to each of the preset conditions and the value of each target performance parameter under the refrigeration condition corresponding to each of the preset conditions to obtain the evaluation result, which indicates the impact of the total number of compression stages and the refrigeration condition on each of the multiple performance parameters.

[0120] In some embodiments, the evaluation submodule may include: a first evaluation unit, configured to compare and evaluate the exhaust temperature, the multi-stage isentropic compression specific work, the multi-stage isentropic compression specific cooling capacity, and the values ​​of the compressed air intake volume at each stage corresponding to each total number of compression stages, to obtain a first evaluation result, wherein the first evaluation result includes a change trend of the exhaust temperature, the change trend of the specific work, the change trend of the specific cooling capacity, and the change trend of the compressed air intake volume at each stage as the total number of compression stages increases; a second evaluation unit, configured to compare and evaluate the values ​​of the ideal isentropic compression refrigeration energy efficiency, the values ​​of the multi-stage compression work coefficient, the values ​​of the multi-stage cooling capacity coefficient, and the values ​​of the isentropic compression refrigeration energy efficiency under each total number of compression stages and each refrigeration operating condition, to obtain a second evaluation result, the second evaluation result including a change trend of the value of the ideal isentropic compression refrigeration energy efficiency, the change trend of the value of the multi-stage compression work coefficient, the change trend of the value of the multi-stage cooling capacity coefficient, and the change trend of the value of the isentropic compression refrigeration energy efficiency as the total number of compression stages increases; a third evaluation unit, configured to obtain a third evaluation result based on a change trend of a value of the ideal isentropic compression refrigeration energy efficiency of the compressor under different refrigeration conditions, a change trend of a value of the multi-stage compression work coefficient, a change trend of a value of the multi-stage cooling capacity coefficient, and a change trend of a value of the isentropic compression refrigeration energy efficiency; The result generating unit is configured to obtain the evaluation result according to the first evaluation result, the second evaluation result and the third evaluation result.

[0121] In some embodiments, the apparatus may further comprise: an acquisition module, configured to acquire a value of the isentropic compression efficiency of the compressor under each of the preset conditions; An analysis module is used to compare and analyze the total number of compression stages corresponding to each of the preset conditions and the values ​​of the isentropic compression efficiency under the refrigeration conditions corresponding to each of the preset conditions, and to take the total compression stages and refrigeration conditions corresponding to the maximum value of the isentropic compression efficiency as the target total compression stages and target conditions of the compressor.

[0122] The specific implementation of the compressor performance evaluation device is basically the same as the specific embodiment of the above-mentioned compressor performance evaluation method, and will not be repeated here.

[0123] The present application also provides an electronic device comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the compressor performance evaluation method described above when executing the computer program. The electronic device can be any smart terminal, such as a tablet computer or an in-vehicle computer.

[0124] See also Figure 12 , Figure 12 The hardware structure of an electronic device according to another embodiment is shown. The electronic device includes: The processor 801 may be implemented as a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of the present application. The memory 802 can be implemented in the form of a read-only memory (ROM), a static storage device, a dynamic storage device, or a random access memory (RAM). The memory 802 can store an operating system and other application programs. When the technical solutions provided in the embodiments of this specification are implemented through software or firmware, the relevant program code is stored in the memory 802 and is called by the processor 801 to execute the compressor performance evaluation method of the embodiments of this application. Input / output interface 803, used to implement information input and output; Communication interface 804, used to implement communication interaction between this device and other devices, which can be achieved through wired means (such as USB, network cable, etc.) or wireless means (such as mobile network, WiFi, Bluetooth, etc.); Bus 805 , which transmits information between various components of the device (e.g., processor 801 , memory 802 , input / output interface 803 , and communication interface 804 ); The processor 801 , the memory 802 , the input / output interface 803 and the communication interface 804 are connected to each other in communication within the device via a bus 805 .

[0125] An embodiment of the present application further provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the above-mentioned compressor performance evaluation method is implemented.

[0126] The memory, as a non-transient computer-readable storage medium, can be used to store non-transient software programs and non-transient computer executable programs. In addition, the memory may include a high-speed random access memory and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some embodiments, the memory may optionally include a memory remotely arranged relative to the processor, and these remote memories may be connected to the processor via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0127] The compressor performance evaluation method, compressor performance evaluation device, electronic device and storage medium provided in the embodiments of the present application construct a thermodynamic cycle process according to the compression process of the compressor under multiple preset conditions. Different preset conditions include at least one of the total number of compression stages and the refrigeration working condition. In this way, the influence of different working conditions and the number of compression stages on the compressor performance can be fully considered. For each preset condition, a mathematical model of the compressor is established based on the constructed thermodynamic cycle process. The mathematical model includes multiple target performance parameters for evaluating the performance of the compressor, which can fully reflect the performance characteristics of the compressor under the condition. The mathematical model of the compressor under the preset conditions is fitted with the thermophysical parameters of the refrigerant to obtain the specific value of each target performance parameter. The theoretical model is combined with the actual working condition to improve the accuracy of the evaluation result. Finally, the performance comparison and evaluation of the multiple target performance parameters of the compressor under each preset condition is performed 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 working conditions can be found. The present application constructs thermodynamic cycle processes and mathematical models under different preset conditions, combines the refrigerant thermophysical parameters to obtain the target performance value and performs comparative evaluation, which can accurately quantify the compressor performance and eliminate external environmental interference.

[0128] The embodiments described in the embodiments of this application are intended to more clearly illustrate the technical solutions of the embodiments of this application and do not constitute a limitation on the technical solutions provided by the embodiments of this application. Those skilled in the art will appreciate that with the evolution of technology and the emergence of new application scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0129] Those skilled in the art will understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of the present application, and may include more or fewer steps than shown in the figures, or a combination of certain steps, or different steps.

[0130] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, i.e., they may be located in one place or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of this embodiment.

[0131] Those skilled in the art will appreciate that all or some of the steps in the methods, systems, and functional modules / units in the devices disclosed above may be implemented as software, firmware, hardware, or appropriate combinations thereof.

[0132] The terms "first", "second", "third", "fourth", etc. (if any) in the specification of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0133] It should be understood that in this application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0134] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the above-mentioned units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0135] The units described above as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0136] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0137] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes multiple instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of various embodiments of the present application. The aforementioned storage medium includes: various media that can store programs, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0138] The preferred embodiments of the present invention are described above with reference to the accompanying drawings, but are not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and essence of the present invention should be within the scope of the present invention.

Claims

1. A compressor performance evaluation method, characterized in that: The method comprises: constructing a thermodynamic cycle flow of the compressor under each of the preset conditions according to a compression process of the compressor under a plurality of preset conditions, wherein the different preset conditions include at least one of a total number of compression stages and a refrigeration operating condition, and the refrigeration operating condition corresponds to an evaporation temperature and a condensation temperature; For each of the preset conditions, based on the thermodynamic cycle process of the compressor under the preset conditions, a mathematical model of the compressor under the preset conditions is constructed, wherein the mathematical model includes a plurality of target performance parameters for evaluating the performance of the compressor; Fitting the mathematical model of the compressor under the preset conditions with the thermophysical property parameters of the refrigerant of the compressor to obtain the value of each target performance parameter of the compressor under the preset conditions; A performance comparison evaluation is performed on the values ​​of the plurality of target performance parameters of the compressor under each of the preset conditions to obtain an evaluation result.

2. The method according to claim 1, characterized in that The step of constructing a thermodynamic cycle flow of the compressor under each of the preset conditions according to the compression process of the compressor under the multiple preset conditions includes: 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.

3. The method according to claim 1, characterized in that For each of the preset conditions, based on the thermodynamic cycle process of the compressor under the preset conditions, a mathematical model of the compressor under the preset conditions is constructed, including: For each of the preset conditions, obtaining a plurality of first performance parameters of the compressor under the preset conditions, where the first performance parameters are calculated based on existing performance parameters of the compressor; The mathematical model of the compressor under the preset conditions is constructed based on the thermodynamic cycle process and the plurality of the first performance parameters.

4. The method according to claim 1, wherein The thermophysical property 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 energy efficiency, multi-stage compression work coefficient, multi-stage refrigeration capacity coefficient, isentropic compression efficiency and isentropic compression refrigeration energy efficiency. The multiple second performance parameters include exhaust temperature, multi-stage isentropic compression specific work, multi-stage isentropic compression specific refrigeration capacity and compression intake volume of each stage. The fitting of 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 includes: For each of the preset conditions, the following processing is performed: Fitting the saturation pressure, the saturation 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 specific work, a value of the multi-stage isentropic compression specific refrigeration capacity, and a value of the compression intake volume of each stage; Taking the difference between the saturated liquid specific enthalpy and the saturated gas specific enthalpy as the value of the ideal specific cooling capacity; The integral of the specific enthalpy difference from the evaporator pressure to the condenser pressure of the compressor is used as the value of the specific isentropic compression work; The ratio of the ideal specific cooling capacity to the specific isentropic compression work is used as the ideal isentropic compression refrigeration energy efficiency; The ratio of the multi-stage isentropic compression ratio cooling capacity to the ideal ratio cooling capacity is used as the multi-stage cooling capacity coefficient; The ratio of the value of the isentropic compression work to the value of the multi-stage isentropic compression work coefficient is used as the value of the multi-stage compression work coefficient; The ratio of the multi-stage isentropic compression specific work value to the actual specific work value is used as the isentropic compression efficiency value; The value of the isentropic compression refrigeration energy efficiency is obtained according to 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.

5. The method according to claim 4, characterized in that The comparative evaluation of the values ​​of the plurality of target performance parameters of the compressor under each of the preset conditions to obtain an evaluation result includes: For each of the preset conditions, obtaining values ​​of a plurality of target performance parameters of the compressor under the preset condition; The total number of compression stages corresponding to each of the preset conditions and the value of each target performance parameter under the refrigeration condition corresponding to each of the preset conditions are compared and evaluated to obtain the evaluation result, which indicates the impact of the total number of compression stages and the refrigeration condition on each of the multiple performance parameters.

6. The method according to claim 5, characterized in that Comparing and evaluating the total number of compression stages corresponding to each of the preset conditions and the value of each of the target performance parameters under the refrigeration conditions corresponding to each of the preset conditions to obtain the evaluation results includes: Comparing and evaluating the exhaust temperature, the multi-stage isentropic compression specific work, the multi-stage isentropic compression specific cooling capacity, and the values ​​of the compressed air intake volume at each stage corresponding to each total number of compression stages, to obtain a first evaluation result, the first evaluation result including a change trend of the exhaust temperature value, a change trend of the specific work value, a change trend of the specific cooling capacity value, and a change trend of the compressed air intake volume at each stage as the total number of compression stages increases; Comparing and evaluating the values ​​of the ideal isentropic compression refrigeration energy efficiency, the values ​​of the multi-stage compression work coefficient, the values ​​of the multi-stage cooling capacity coefficient, and the values ​​of the isentropic compression refrigeration energy efficiency for each total number of compression stages and each refrigeration operating condition, to obtain a second evaluation result, the second evaluation result including a changing trend of the value of the ideal isentropic compression refrigeration energy efficiency, the changing trend of the value of the multi-stage compression work coefficient, the changing trend of the value of the multi-stage cooling capacity coefficient, and the changing trend of the value of the isentropic compression refrigeration energy efficiency as the total number of compression stages increases; Obtaining a third evaluation result based on a change trend of the ideal isentropic compression refrigeration energy efficiency value of the compressor under different refrigeration conditions, a change trend of the multi-stage compression work coefficient value, a change trend of the multi-stage cooling capacity coefficient value, and a change trend of the isentropic compression refrigeration energy efficiency value; The evaluation result is obtained according to the first evaluation result, the second evaluation result and the third evaluation result.

7. The method according to claim 5, characterized in that After performing a performance comparison evaluation on the values ​​of the plurality of target performance parameters of the compressor under each of the preset conditions to obtain an evaluation result, the method further includes: Obtaining a value of the isentropic compression efficiency of the compressor under each of the preset conditions; A comparative analysis is performed on the total number of compression stages corresponding to each of the preset conditions and the values ​​of the isentropic compression efficiency under the refrigeration conditions corresponding to each of the preset conditions, and the total compression stages and refrigeration conditions corresponding to the maximum value of the isentropic compression efficiency are taken as the target total compression stages and target conditions of the compressor.

8. A compressor performance evaluation device, characterized in that: The device comprises: a first constructing module, configured to construct, based on the compression process of the compressor under a plurality of preset conditions, a thermodynamic cycle flow of the compressor under each of the preset conditions, wherein the preset conditions include at least one of a total number of compression stages and a refrigeration operating condition, the refrigeration operating condition corresponding to an evaporation temperature and a condensation temperature; a second building module, configured to build, for each of the preset conditions, a mathematical model of the compressor under the preset conditions based on the thermodynamic cycle process of the compressor under the preset conditions, wherein the mathematical model includes a plurality of target performance parameters for evaluating the performance of the compressor; a fitting module, configured to fit the mathematical model of the compressor under the preset conditions with the thermophysical property parameters of the refrigerant of the compressor to obtain a value of each target performance parameter of the compressor under the preset conditions; An evaluation module is used to perform a performance comparison evaluation on the values ​​of the multiple target performance parameters of the compressor under each of the preset conditions to obtain an evaluation result.

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

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

Images