Orcc working medium screening method, system, medium and product based on critical temperature criterion

Abstract

The application discloses an ORC working medium screening method, system, medium and product based on a critical temperature criterion, relates to the field of ORC working medium screening, and comprises the following steps: firstly, determining a heat source temperature range of an ORC system and establishing a working medium database; then, setting a critical temperature criterion, so that the critical temperature of the working medium is close to but not higher than the heat source temperature, and the working medium meeting the condition is preliminarily screened according to the critical temperature criterion; then, calculating an evaporator integral temperature difference corresponding to each preselected working medium, wherein the evaporator integral temperature difference is determined by the relationship between the total heat exchange amount in the heat exchange process and the temperatures of the hot medium and the cold medium; then, establishing an evaporator loss prediction model according to the linear relationship between the evaporator integral temperature difference and the evaporator loss, and calculating the system thermal efficiency; finally, combining the economic evaluation of the market price of the working medium, and considering the environmental influence, so as to finally determine the target working medium. The application can quickly screen the optimal working medium for the heat source with different temperature ranges, and improves the efficiency and accuracy of the working medium screening.

Description

Technical Field

[0001] This application belongs to the field of ORC working fluid screening, and in particular relates to ORC working fluid screening methods, systems, media and products based on critical temperature criteria. Background Technology

[0002] With the global energy crisis becoming increasingly prominent, energy conservation and emission reduction have become core issues for the international community. The efficient utilization of low- and medium-temperature industrial waste heat and renewable energy is considered the "fifth conventional energy source," and is of great significance for achieving energy conservation goals. The Organic Rankine Cycle (ORC), as a typical low- and medium-temperature thermal energy utilization technology, uses low-boiling-point organic matter as the working fluid. The choice of working fluid directly affects the system's efficiency, energy output, economic performance, and environmental performance.

[0003] However, current ORC working fluid selection and parameter design cannot systematically analyze complex operating conditions with different waste heat temperatures, making it difficult to comprehensively evaluate the thermodynamic performance, economic performance, and environmental adaptability of various working fluids.

[0004] In related technologies, Wang et al. found that organic working fluids with lower molecular entropy can produce higher thermal efficiency, while Rayegen et al. confirmed that organic working fluids with higher critical temperatures are beneficial to improving cycle thermal efficiency.

[0005] However, existing technologies lack systematic methods for selecting working fluids, making it difficult to find the optimal working fluid for use under complex working conditions. This situation needs further improvement. Summary of the Invention

[0006] This application provides an ORC working fluid screening method based on the critical temperature criterion, addressing the lack of systematic evaluation in existing working fluid screening technologies. This method establishes a relationship criterion between the working fluid's critical temperature and the heat source temperature, and combines this with evaporator integral temperature difference and loss analysis to systematically evaluate the thermodynamic performance, economic performance, and environmental adaptability of the working fluid, achieving optimal working fluid selection for different heat source temperatures.

[0007] Firstly, this application provides an ORC working fluid screening method based on the critical temperature criterion, including: Determine the temperature range of the heat source in the ORC system; Based on the heat source temperature range, a critical temperature criterion is set and a working fluid is pre-selected. The critical temperature criterion satisfies... ,and Approaching but not higher ,in, The critical temperature of the working fluid. The temperature of the heat source. This is the condensation temperature; Calculate the corresponding integral temperature difference of the evaporator based on the pre-selected working fluid; Based on the linear relationship between the integral temperature difference of the evaporator and the evaporator loss, and combined with the thermodynamic properties, economic performance and environmental adaptability of the pre-selected working fluid, the target working fluid is determined.

[0008] By adopting the above technical solution, this application first determines the heat source temperature range of the ORC system and establishes a working fluid database; then, it sets a critical temperature criterion so that the critical temperature of the working fluid is close to but not higher than the heat source temperature, and preliminarily screens working fluids that meet the conditions; next, it calculates the evaporator integral temperature difference corresponding to each pre-selected working fluid, which is determined by the relationship between the total heat exchange and the temperatures of the hot and cold media; then, it establishes a loss prediction model based on the linear relationship between the evaporator integral temperature difference and the evaporator loss, and calculates the system thermal efficiency; finally, it conducts an economic evaluation based on the working fluid market price and considers the environmental impact, and finally determines the target working fluid; this approach can quickly screen the optimal working fluid for heat sources with different temperature ranges, improving the efficiency and accuracy of working fluid screening. In conjunction with some embodiments of the first aspect, in some embodiments, the heat source is industrial waste heat or renewable energy heat. In conjunction with some embodiments of the first aspect, in some embodiments, the preselected working fluid is a single organic working fluid or a mixture of organic working fluids, wherein the organic working fluid is determined comprehensively based on thermophysical performance compatibility, environmental friendliness, chemical stability, safety and economic flexibility.

[0009] By adopting the above technical solution, the pre-selected working medium is a single organic working medium or a mixture of organic working media, which is determined comprehensively based on thermophysical performance compatibility, environmental friendliness, chemical stability, safety and economic flexibility, thereby improving the comprehensiveness and practicality of working medium screening. In conjunction with some implementations of the first aspect, in some implementations, the calculation of the corresponding evaporator integral temperature difference based on the pre-selected working fluid is specifically performed using the following formula: ,in, The integral temperature difference of the evaporator. The total heat exchanged during the heat exchange process. The temperature of the heat medium. This refers to the temperature of the cold medium.

[0010] By adopting the above technical solution, this application establishes a quantitative calculation method for the integral temperature difference of the evaporator. By evaluating the heat transfer performance of the working fluid through the relationship between the temperature of the hot medium, the temperature of the cold medium, and the heat exchange, it provides a reliable data basis for subsequent loss analysis, making the working fluid selection process more scientific and accurate. In conjunction with some implementations of the first aspect, in some implementations, determining the target working fluid based on the linear relationship between the evaporator integral temperature difference and evaporator losses, combined with the thermodynamic properties, economic performance, and environmental adaptability of the pre-selected working fluid, specifically includes: A linear fitting equation is established based on the evaporator integral temperature difference and evaporator loss data to obtain a loss prediction model; The thermal efficiency of the system is calculated based on the aforementioned loss prediction model, and the thermodynamic performance data of each working fluid are obtained. Based on the aforementioned thermodynamic performance data and working fluid market prices, an economic evaluation result is obtained; Based on the aforementioned thermodynamic performance data and the aforementioned economic evaluation results, a preliminary list of working fluids is determined; An environmental impact assessment was conducted based on the preliminary screening of the working fluid list to obtain the final target working fluid.

[0011] By adopting the above technical solution, this application establishes a complete evaluation process from loss prediction to final screening. By predicting loss through linear fitting equations and combining thermal efficiency calculation, economic evaluation and environmental impact analysis, a multi-dimensional quantitative evaluation of working fluid performance is achieved. In conjunction with some implementations of the first aspect, in some implementations, the process of pre-selecting the working fluid based on a preset critical temperature criterion specifically includes: A working fluid database is established based on molecular weight and critical parameters to obtain a list of candidate working fluids; Based on the candidate working fluid list, the ratio of specific heat capacity to latent heat of vaporization of the working fluid is analyzed to obtain the heat transfer characteristic data of the working fluid; Based on the degree of matching between the heat transfer characteristics data of the working fluid and the temperature of the heat source, a pre-selected working fluid that meets the critical temperature criterion is obtained.

[0012] By adopting the above technical solution, this application forms a systematic pre-selection process from the establishment of the working fluid database to the analysis of heat transfer characteristics. Through comprehensive evaluation of thermodynamic parameters such as molecular weight, critical parameters, and the ratio of specific heat capacity to latent heat of vaporization, it ensures that the pre-selected working fluid has good matching with the heat source temperature. In conjunction with some embodiments of the first aspect, in some embodiments, a thermal oil electric heater is used to simulate the heat source of the ORC system. Before determining the temperature range of the heat source of the ORC system, the method further includes: The heater power is set according to the preset heat source simulation requirements to obtain a stable heat source temperature; The target heat exchange capacity is obtained by adjusting the flow rate of the heat transfer oil based on the heat source temperature. The optimal heat transfer process is obtained based on the operating parameters of the target heat exchange control system.

[0013] By adopting the above technical solution, precise control and stable output of heat source temperature were achieved. By adjusting the heater power and heat transfer oil flow rate, the target heat exchange capacity was established, the system operating parameters were optimized, and the reliability of the heat source simulation process and the optimal heat transfer effect were ensured. In a second aspect, embodiments of this application provide an ORC working fluid screening system based on a critical temperature criterion, comprising: one or more processors and a memory; the memory is coupled to one or more processors, the memory is used to store computer program code, the computer program code including computer instructions, and one or more processors call the computer instructions to cause the system to perform the method described in the first aspect and any possible implementation thereof. Thirdly, embodiments of this application provide a computer-readable storage medium including instructions that, when executed on a system, cause the system to perform the method described in the first aspect and any possible implementation thereof. Fourthly, embodiments of this application provide a computer program product that, when run on a system, causes the system to execute the method described in any possible implementation of the first aspect. One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages: 1. This application provides an ORC working fluid screening method based on the critical temperature criterion. First, the heat source temperature range of the ORC system is determined, and a working fluid database is established. Then, a critical temperature criterion is set, ensuring that the critical temperature of the working fluid is close to but not higher than the heat source temperature, thereby initially screening working fluids that meet the criteria. Next, the evaporator integral temperature difference corresponding to each pre-selected working fluid is calculated. The evaporator integral temperature difference is determined by the relationship between the total heat exchange and the temperatures of the hot and cold media. Then, a loss prediction model is established based on the linear relationship between the evaporator integral temperature difference and evaporator loss, and the system thermal efficiency is calculated. Finally, an economic evaluation is conducted in conjunction with the working fluid market price, and environmental impact is considered to ultimately determine the target working fluid. This method can quickly screen the optimal working fluid for heat sources with different temperature ranges, improving the efficiency and accuracy of working fluid screening.

[0014] 2. This application provides an ORC working fluid screening method based on the critical temperature criterion. The pre-selected working fluid is a single organic working fluid or a mixture of organic working fluids. The selection is based on a comprehensive consideration of thermophysical performance compatibility, environmental friendliness, chemical stability, safety and economic flexibility, which improves the comprehensiveness and practicality of working fluid screening.

[0015] 3. This application provides an ORC working fluid screening method based on the critical temperature criterion, establishes a quantitative calculation method for the integral temperature difference of the evaporator, and evaluates the heat transfer performance of the working fluid by the relationship between the temperature of the hot medium, the temperature of the cold medium and the heat exchange, providing a reliable data basis for subsequent loss analysis, and making the working fluid screening process more scientific and accurate. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating the ORC working fluid screening method based on the critical temperature criterion in an embodiment of this application.

[0017] Figure 2 This is another flowchart illustrating the ORC working fluid screening method based on the critical temperature criterion in this application.

[0018] Figure 3 This is a schematic diagram of the physical device structure of the ORC working fluid screening system based on the critical temperature criterion provided in the embodiments of this application. Detailed Implementation

[0019] The terminology used in the following embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. As used in the specification and appended claims of this application, the singular expressions “a,” “an,” “the,” “the,” “the,” and “this” are intended to include the plural expressions as well, unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in this application refers to any or all possible combinations including one or more of the listed items.

[0020] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature, and in the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more. In the field of energy utilization, the efficient use of industrial waste heat and renewable energy is of great significance for achieving energy conservation and emission reduction goals. The Organic Rankine Cycle (ORC), as a mature medium- and low-temperature thermal energy utilization technology, relies heavily on the selection of the working fluid for its system performance.

[0021] In related technologies, working fluid selection mainly relies on empirical judgment and lacks a systematic evaluation method, making it difficult to find the optimal working fluid for heat sources with different temperature ranges. Existing research shows that the critical temperature of the working fluid is closely related to system efficiency, but determining a suitable temperature criterion remains a key issue in working fluid selection.

[0022] This application is mainly applied to industrial waste heat recovery and renewable energy power generation scenarios, such as waste heat utilization in industries like steel and chemicals, as well as solar and geothermal power generation systems. In these applications, the heat source temperature range is wide, and the selection of the working fluid directly affects the system's economy and environmental adaptability. To address the aforementioned technical problems, this application provides an ORC working fluid screening method, system, medium, and product based on the critical temperature criterion. An embodiment is described below in conjunction with... Figure 1 The ORC working fluid screening method based on the critical temperature criterion in the embodiments of this application is described as follows: Please see Figure 1This is a flowchart illustrating an ORC working fluid screening method based on the critical temperature criterion in an embodiment of this application.

[0023] S101. Determine the temperature range of the heat source for the ORC system.

[0024] Specifically, the heat source can be industrial waste heat, such as excess heat generated during factory production, or renewable energy heat, such as heat converted from solar or wind power. For industrial waste heat, its temperature range can be measured by installing temperature sensors at the waste heat emission outlet of the factory; for renewable energy heat, the temperature range can be determined based on the operating parameters of the corresponding energy collection device.

[0025] S102. Based on the temperature range of the heat source, set the critical temperature criterion and pre-select the working fluid.

[0026] Among them, the critical temperature criterion satisfies ,and Approaching but not higher ,in, The critical temperature of the working fluid. The temperature of the heat source. This is the condensation temperature.

[0027] Specifically, the pre-selected working fluid can be a single organic working fluid, such as R245fa, a common organic working fluid with good thermophysical properties; or it can be a mixture of organic working fluids, such as a mixture of R134a and R227ea in a certain proportion. The determination of the organic working fluid requires comprehensive consideration of thermophysical performance compatibility, environmental friendliness, chemical stability, safety, and economic flexibility. For example, in terms of environmental friendliness, working fluids with low ozone layer depletion and low greenhouse potential should be selected; in terms of safety, flammable, explosive, and highly toxic working fluids should be avoided.

[0028] The system first establishes a working fluid database based on molecular weight and critical parameters to obtain a list of candidate working fluids. Information such as the molecular weight and critical parameters of various organic working fluids can be collected and stored in the database. Then, based on the candidate working fluid list, the specific heat capacity to latent heat of vaporization ratio of the working fluid is analyzed to obtain working fluid heat transfer characteristic data. Finally, based on the degree of matching between the working fluid heat transfer characteristic data and the heat source temperature, pre-selected working fluids that meet the critical temperature criterion are obtained. For example, if the heat source temperature is high, a working fluid with good heat transfer characteristics and the ability to adapt to high temperatures is selected.

[0029] In some embodiments, the system establishes a multi-dimensional working fluid evaluation system. In addition to the working fluid database, it also includes a working fluid property parameter table, a thermodynamic performance table, and an environmental indicator table, recording the basic physical properties, thermodynamic parameters, and environmental impact indicators of the working fluid, respectively. A support vector machine (SVM) algorithm is used to construct a working fluid performance prediction model, establishing the mapping relationship between working fluid property parameters and thermodynamic performance, and between operating parameters and system performance, thereby achieving intelligent prediction and evaluation of the performance of pre-selected working fluids.

[0030] S103. Calculate the corresponding integral temperature difference of the evaporator based on the pre-selected working fluid.

[0031] Specifically through the formula Calculations are performed, in which, The integral temperature difference of the evaporator. The total heat exchanged during the heat exchange process. The temperature of the heat medium. The temperature of the cold medium is denoted as ΔT. In practical calculations, the total heat exchange can be calculated by measuring the temperatures of the hot and cold media at the inlet and outlet of the evaporator, combined with the heat balance principle of the heat exchanger, and then the integral temperature difference of the evaporator can be calculated. Furthermore, the system arranges ambient temperature sensors around the temperature measurement points at the evaporator inlet and outlet, and considers the thickness and thermal conductivity of the pipe insulation layer to establish a heat loss compensation model: ΔT 补偿 =k1(T 环境 -T 测量 The formula is: k1 + k2(δ / λ), where k1 is the ambient temperature influence coefficient, k2 is the insulation characteristic coefficient, δ is the insulation layer thickness, and λ is the thermal conductivity of the insulation material. The system uses this model to correct the measured temperature in real time, ensuring the accuracy of the heat exchange calculation.

[0032] To improve the system's adaptability to heat source temperature fluctuations, this application establishes a heat source characteristic analysis system, including a temperature fluctuation model. The system models the periodic changes in heat source temperature using methods such as Fourier analysis, for example, the fluctuation pattern of waste heat temperature in a steel plant within the range of 120℃-150℃. Based on the temperature fluctuation model, the system automatically divides the operating conditions into high-temperature, medium-temperature, and low-temperature segments. For different temperature ranges, a working fluid mixing optimization system is constructed. For example, in the high-temperature segment, the mixing ratio of R227ea is increased to improve heat transfer efficiency, while in the low-temperature segment, the ratio of R134a is increased to ensure sufficient heat exchange. The system collects parameters such as temperature and pressure through an online monitoring module, the evaluation feedback module calculates the current integral temperature difference and heat exchange efficiency, and the optimization execution module adjusts the working fluid ratio accordingly to achieve dynamic optimization of the evaporator's heat exchange performance.

[0033] S104. Based on the linear relationship between the integral temperature difference of the evaporator and the evaporator loss, and combined with the thermodynamic properties, economic performance and environmental adaptability of the pre-selected working fluid, determine the target working fluid.

[0034] Specifically, the system first establishes a linear fitting equation based on evaporator integral temperature difference and evaporator loss data to obtain a loss prediction model. A large amount of evaporator integral temperature difference and loss data under different operating conditions can be collected, and linear fitting is performed using mathematical methods such as the least squares method. Then, the system thermal efficiency is calculated based on the loss prediction model, obtaining the thermodynamic performance data of each working fluid. Based on the thermodynamic performance data and working fluid market prices, economic evaluation results are obtained, such as comparing the costs required for different working fluids to achieve the same thermal efficiency. Based on the thermodynamic performance data and economic evaluation results, a preliminary list of working fluids is determined. Finally, an environmental impact assessment is conducted based on the preliminary list of working fluids, such as assessing the carbon emissions of the working fluids, ultimately yielding the final target working fluid.

[0035] In the above embodiments, a working fluid screening method based on the critical temperature criterion is established to systematically evaluate and select the working fluid. First, the system heat source temperature range is determined, and a critical temperature criterion is set for preliminary screening. Then, the working fluid is quantitatively evaluated through evaporator integral temperature difference calculation and loss prediction model. Finally, the optimal working fluid is determined by comprehensively considering thermal performance, economic efficiency, and environmental impact.

[0036] In the above embodiments, a systematic screening of working fluids was achieved through the critical temperature criterion and integrated temperature difference analysis. However, in practical applications, experimental verification is required to validate the reliability of the screening method. To further improve the accuracy and practicality of working fluid screening, this application also provides another ORC working fluid screening method based on the critical temperature criterion. The following is a combination of... Figure 2 Another ORC working fluid screening method based on the critical temperature criterion is described in the embodiments of this application: Please see Figure 2 This is another flowchart illustrating an ORC working fluid screening method based on the critical temperature criterion in an embodiment of this application.

[0037] S201. Set the heater power according to the preset heat source simulation requirements to obtain a stable heat source temperature.

[0038] Specifically, a thermal oil electric heater is used as the heat source simulation device, and the temperature of the thermal oil is controlled by adjusting the input power of the heater. For example, if it is necessary to simulate 120°C of industrial waste heat, the heater power is set at an appropriate level to stabilize the thermal oil temperature at around 120°C. To ensure temperature stability, a temperature sensor can be installed on the heater for real-time monitoring and feedback control.

[0039] S202. Adjust the flow rate of the heat transfer oil based on the heat source temperature to obtain the target heat exchange.

[0040] Specifically, the flow rate is controlled by adjusting the speed of the heat transfer oil circulation pump, thereby achieving the expected heat exchange. The flow rate of the heat transfer oil can be measured by a flow meter, and the actual heat exchange can be calculated by combining this with the inlet and outlet temperature difference measured by a temperature sensor. If the actual heat exchange deviates from the target value, the flow rate is adjusted to correct for this deviation until the desired effect is achieved.

[0041] S203. Based on the operating parameters of the target heat exchange control system, the optimal heat transfer process is obtained.

[0042] Specifically, system operating parameters include working fluid flow rate, evaporation pressure, and superheat. Adjusting these parameters can optimize the heat transfer process and improve heat exchange efficiency. For example, the working fluid flow rate can be changed by adjusting the speed of the working fluid circulation pump, the evaporation pressure can be controlled by adjusting the expansion valve opening, and the superheat can be controlled by adjusting the heater power. After completing the commissioning of the heat source simulation system, the temperature range of the system under different operating conditions is measured and recorded, providing an experimental basis for subsequent working fluid selection. For example, the system's operating data at different temperature levels can be obtained by changing the heater power.

[0043] In the above embodiments, a controllable experimental environment was established by simulating the actual heat source using a thermal oil electric heater, which can accurately simulate the characteristics of the heat source within different temperature ranges. By precisely controlling the heater power, thermal oil flow rate, and system operating parameters, the stability and reliability of the heat source simulation were ensured. The system in the embodiments of this invention is described below from the perspective of hardware processing. Please refer to [link / reference needed]. Figure 3 This is a schematic diagram of the physical device structure of the ORC working fluid screening system based on the critical temperature criterion provided in the embodiments of this application.

[0044] It should be noted that, Figure 3 The system structure shown is merely an example and should not be construed as limiting the functionality or scope of application of the embodiments of the present invention. ORC working fluid screening method based on critical temperature criterion. like Figure 3 As shown, the system includes a Central Processing Unit (CPU) 301, which can perform various appropriate actions and processes based on a program stored in Read-Only Memory (ROM) 302 or a program loaded from storage portion 308 into Random Access Memory (RAM) 303, such as executing the methods described in the above embodiments. The RAM 303 also stores various programs and data required for system operation. The CPU 301, ROM 302, and RAM 303 are interconnected via a bus 304. An Input / Output (I / O) interface 305 is also connected to the bus 304.

[0045] The following components are connected to I / O interface 305: input section 306 including a camera, infrared sensor, etc.; output section 307 including a liquid crystal display (LCD) and speakers, etc.; storage section 308 including a hard disk, etc.; and communication section 309 including a network interface card such as a LAN (Local Area Network) card and a modem, etc. Communication section 309 performs communication processing via a network such as the Internet. Drive 310 is also connected to I / O interface 305 as needed. Removable media 311, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., are installed on drive 310 as needed so that computer programs read from them can be installed into storage section 308 as needed.

[0046] In particular, according to embodiments of the present invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present invention include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing computer programs for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via communication section 309, and / or installed from removable medium 311. When the computer program is executed by central processing unit (CPU) 301, it performs the various functions defined in the present invention.

[0047] It should be noted that the computer-readable medium shown in the embodiments of the present invention can be a computer-readable signal medium or a computer-readable storage medium, or any combination thereof. A computer-readable storage medium can be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), flash memory, optical fiber, portable compact disc read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In the present invention, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. In the present invention, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, wherein a computer-readable computer program is carried. The transmitted data signal can take many forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof.

[0048] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. Each block in a flowchart or block diagram may represent a module, segment, or portion of code, which contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0049] In another aspect, the present invention also provides a computer-readable storage medium, which may be included in the system described in the above embodiments; or it may exist independently and not assembled into the system. The storage medium carries one or more computer programs that, when executed by a processor of a system, cause the system to implement the methods provided in the above embodiments.

[0050] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0051] As used in the above embodiments, depending on the context, the term "when..." can be interpreted as "if...", "after...", "in response to determining...", or "in response to detecting...". Similarly, depending on the context, the phrase "when determining..." or "if (the stated condition or event) is interpreted as "if determining...", "in response to determining...", "when (the stated condition or event) is detected", or "in response to detecting (the stated condition or event)".

[0052] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state drive), etc.

[0053] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. This program can be stored in a computer-readable storage medium, and when executed, it can include the processes described in the above method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as ROM or random access memory (RAM), magnetic disks, or optical disks.

Claims

1. An ORC working fluid screening method based on the critical temperature criterion, characterized in that, include: Determine the temperature range of the heat source in the ORC system; Based on the heat source temperature range, a critical temperature criterion is set and a working fluid is pre-selected. The critical temperature criterion satisfies... ,and Approaching but not higher ,in, The critical temperature of the working fluid. The temperature of the heat source. This is the condensation temperature; Calculate the corresponding integral temperature difference of the evaporator based on the pre-selected working fluid; Based on the linear relationship between the integral temperature difference of the evaporator and the evaporator loss, and combined with the thermodynamic properties, economic performance and environmental adaptability of the pre-selected working fluid, the target working fluid is determined.

2. The method according to claim 1, characterized in that, The heat source is industrial waste heat or renewable energy heat.

3. The method according to claim 1, characterized in that, The pre-selected working medium is a single organic working medium or a mixture of organic working mediums. The organic working medium is determined comprehensively based on its thermophysical performance compatibility, environmental friendliness, chemical stability, safety, and economic flexibility.

4. The method according to claim 1, characterized in that, The calculation of the corresponding evaporator integral temperature difference based on the pre-selected working fluid is specifically performed using the following formula: ,in, The integral temperature difference of the evaporator. The total heat exchanged during the heat exchange process. The temperature of the heat medium. This refers to the temperature of the cold medium.

5. The method according to claim 4, characterized in that, The determination of the target working fluid based on the linear relationship between the integral temperature difference and evaporator loss, combined with the thermodynamic properties, economic performance, and environmental adaptability of the pre-selected working fluid, specifically includes: A linear fitting equation is established based on the evaporator integral temperature difference and evaporator loss data to obtain a loss prediction model; The thermal efficiency of the system is calculated based on the aforementioned loss prediction model, and the thermodynamic performance data of each working fluid are obtained. Based on the aforementioned thermodynamic performance data and working fluid market prices, an economic evaluation result is obtained; Based on the aforementioned thermodynamic performance data and the aforementioned economic evaluation results, a preliminary list of working fluids is determined; An environmental impact assessment was conducted based on the preliminary screening of the working fluid list to obtain the final target working fluid.

6. The method according to claim 1, characterized in that, The process of pre-selecting the working fluid based on a preset critical temperature criterion specifically includes: A working fluid database is established based on molecular weight and critical parameters to obtain a list of candidate working fluids; Based on the candidate working fluid list, the ratio of specific heat capacity to latent heat of vaporization of the working fluid is analyzed to obtain the heat transfer characteristic data of the working fluid; Based on the degree of matching between the heat transfer characteristics data of the working fluid and the temperature of the heat source, a pre-selected working fluid that meets the critical temperature criterion is obtained.

7. The method according to claim 1, characterized in that, The method employs a thermally conductive oil electric heater to simulate the heat source of the ORC system. Before determining the temperature range of the heat source of the ORC system, the method further includes: The heater power is set according to the preset heat source simulation requirements to obtain a stable heat source temperature; The target heat exchange capacity is obtained by adjusting the flow rate of the heat transfer oil based on the heat source temperature. The optimal heat transfer process is obtained based on the operating parameters of the target heat exchange control system.

8. An ORC working fluid screening system based on the critical temperature criterion, characterized in that, The system includes: One or more processors and a memory; the memory is coupled to the one or more processors, the memory being used to store computer program code, the computer program code including computer instructions, the one or more processors invoking the computer instructions to cause the system to perform the method as described in any one of claims 1-7.

9. A computer-readable storage medium comprising instructions, characterized in that, When the instructions are executed on the system, the system performs the method as described in any one of claims 1-7.

10. A computer program product, characterized in that, When the computer program product is run on the system, the system performs the method as described in any one of claims 1-7.

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