Multi-dimensional comprehensive performance evaluation method, system and device for fire storage combined system and medium

Abstract

This invention belongs to the field of thermal power generation peak-shaving technology, specifically involving a multi-dimensional comprehensive performance evaluation method for combined thermal power and thermal energy storage systems. Addressing the shortcomings of existing integrated thermal power and thermal energy storage systems, which lack a comprehensive evaluation system covering multiple performance characteristics for engineering selection, this invention adopts the following technical solution: The multi-dimensional comprehensive performance evaluation method for combined thermal power and thermal energy storage systems includes: constructing a model of a thermal power unit coupled with a molten salt thermal energy storage system; selecting and calculating performance evaluation indicators for the coupled system, including static and dynamic performance indicators; performing subjective and objective weighting based on the analytic hierarchy process (AHP) and entropy weighting method to obtain combined weights; and using the TOPSIS method to calculate the relative proximity of each evaluation object to the positive and negative ideal solutions, achieving comprehensive decision-making under multiple indicator conditions. The beneficial effect of this invention is that it better meets the needs of engineering practice for selecting schemes for coal-fired power units coupled with molten salt thermal energy storage systems.

Description

Technical Field

[0001] This invention belongs to the field of thermal power generation peak shaving technology, specifically involving a multi-dimensional comprehensive performance evaluation method, system, equipment and medium for thermal power storage combined system. Background Technology

[0002] Under the strategic goal of "dual carbon" (carbon diversification and energy conservation), the power system is accelerating its transition towards a higher proportion of renewable energy. However, wind and solar power are characterized by significant intermittency and volatility, leading to a continuous increase in grid peak-shaving pressure. As a stable supporting power source for the current power system, coal-fired power units are required to have stronger flexible adjustment capabilities to adapt to the rapid load changes brought about by the large-scale grid connection of new energy sources.

[0003] Molten salt thermal energy storage systems possess advantages such as large energy storage capacity, strong heat release stability, and efficient and controllable heat storage and release processes, and are considered an important technical approach to enhance the peak-shaving capacity of coal-fired power units. Its basic coupling mechanism is as follows: molten salt is heated for energy storage using waste heat or additional heating during low-load periods of the unit; during peak grid demand or rapid ramp-up phases, heat is released from the molten salt to the feedwater or steam system, enabling a rapid increase in unit load, thereby enhancing grid support capacity and system operational flexibility.

[0004] The operational performance of coal-fired power units coupled with molten salt thermal energy storage systems is influenced by a variety of factors, and their performance evaluation indicators typically include multiple dimensions such as heat storage and release capacity, peak-shaving performance, load response rate, and thermal performance. However, existing research largely focuses on the performance analysis of the coupled system and the comparison of single indicators, lacking a comprehensive evaluation system oriented towards engineering selection that covers multiple performance characteristics. This makes it difficult to accurately determine the overall performance advantages and disadvantages of different coupling schemes in actual operation. Furthermore, existing research on coal-fired power units coupled with molten salt thermal energy storage systems is mostly based on static models established under steady-state conditions. The analysis of system performance mainly focuses on static characteristics such as thermal efficiency and thermal storage capacity, while paying insufficient attention to the dynamic performance exhibited by the system during actual operation. In particular, during unit load change operation and heat storage and release switching, the key dynamic indicator of the system's load change rate has not been fully modeled and quantified, resulting in evaluation results that fail to reflect the dynamic performance of the coupled system.

[0005] Therefore, it is necessary to construct a comprehensive performance evaluation system that takes into account both static and dynamic characteristics and covers multiple performance indicators, so as to objectively and scientifically rank the performance of various coupling schemes and select the optimal scheme. Summary of the Invention

[0006] This invention addresses the deficiency in existing integrated thermal power and thermal energy storage systems, which lack a comprehensive evaluation system covering multiple performance characteristics for engineering selection. It proposes a multi-dimensional comprehensive performance evaluation method suitable for coal-fired power units coupled with molten salt thermal energy storage systems. This method achieves unified quantification and comprehensive evaluation of multiple performance aspects, including system heat storage and release capacity, peak-shaving performance, load change rate, and thermal performance, ultimately guiding engineering selection. This invention also provides a multi-dimensional comprehensive performance evaluation system, computer equipment, and computer-readable storage medium suitable for coal-fired power units coupled with molten salt thermal energy storage systems.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a multi-dimensional comprehensive performance evaluation method for integrated fire-storage systems, wherein the multi-dimensional comprehensive performance evaluation method for integrated fire-storage systems includes:

[0008] Step S1: Construct a model of a thermal power unit coupled with a molten salt thermal storage system; Step S2: Select and calculate the performance evaluation index of the coupled system. The performance evaluation index includes static performance index and dynamic performance index. Step S3: Perform subjective and objective weighting based on the analytic hierarchy process (AHP) and entropy weighting method to obtain the combined weights; Step S4: Using the TOPSIS method, calculate the relative proximity between each evaluation object and the positive and negative ideal solutions to achieve comprehensive decision-making under multiple index conditions.

[0009] As an improvement, in step S1, the coupled molten salt thermal energy storage system model of the thermal power unit includes a pulverizing system model, a steam-water system model, a steam turbine model, a regenerative system, and a molten salt thermal energy storage system model.

[0010] As an improvement, in step S2, the selected performance evaluation indicators include molten salt heat storage and release capacity, peak shaving performance, load increase rate, and thermal performance.

[0011] As an improvement, the heat storage and release capacity of molten salt is referred to as heat storage capacity. Q hse Heat release capacity Q hre express: (20) (twenty one) In the formula: C p,ms The specific heat of molten salt is expressed in kJ / (kg·℃). D ms,hse This indicates the mass flow rate of molten salt in the molten salt heat exchanger, in kg / s. D w,hre This indicates the mass flow rate of the working fluid in the molten salt heat exchanger, in kg / s. T ms,hsei ,T ms,hseo These represent the inlet and outlet temperatures, respectively, of the molten salt in the molten salt heat exchanger, in K. h w,hrei , h w,hreo These represent the enthalpy values ​​at the inlet and outlet of the working fluid in the molten salt heat exchanger, respectively, in kJ / kg; Peak-shaving performance is expressed by peak-shaving capacity and peak-shaving depth. The peak-shaving capacity Δ during the heat storage and release stage is... P hse and Δ P hre The calculation expression is: (twenty two) (twenty three) In the formula: P 0、 P e These represent the output power (MW) of the coal-fired unit under 50% THA and 100% THA rated operating conditions, respectively. P hse , P hre They represent the actual output power of the coupled system during the heat storage and release process, in MW; Peak Shaving Depth l hse , l hre The calculation expression is: (twenty four) (25) Load increase rate v The calculation expression is: (26) In the formula: P 0,1 , P 0,2 Let these represent the initial load and target load of the coupled system, respectively, in MW; t 0 indicates that the unit has begun to change load to match the system. P 0,1 , P 0,2 The time required, in minutes, for the relative deviation between the two values ​​to be less than 0.1%. Thermal performance includes thermal efficiency, thermal efficiency, overall thermal efficiency, overall thermal efficiency, and cycle efficiency.

[0012] As an improvement, step S3 includes: S31. First, subjective empowerment is carried out: S32. Secondly, objective weighting is carried out; S33. Finally, the geometric mean method is used to combine subjective weights and objective weights to obtain the combined weights.

[0013] As an improvement, in S31, the subjective empowerment process includes: Based on the logical relationship between the evaluation objectives and the indicator system, a hierarchical structure model consisting of "objective layer - indicator layer - solution layer" is constructed. Based on expert experience, a judgment matrix is ​​constructed to compare the importance of each indicator at the same level relative to the target at the next higher level. The judgment matrix is ​​decomposed into eigenvalues ​​to find its largest eigenvalue and corresponding eigenvector, and the eigenvector is normalized to obtain the subjective weights of each indicator. Perform a consistency check; In S32, the objective weighting process includes: Construct a decision matrix; Standardize the data in the decision matrix; Based on the standardized decision matrix, the information entropy of each indicator is calculated. Calculate the objective weight of each evaluation indicator based on its information entropy value.

[0014] As an improvement, step S4 includes: S41. Construct a weighted decision matrix; S42. Based on the weighted decision matrix, construct the positive ideal solution and the negative ideal solution respectively. ， A positive ideal solution represents the optimal combination of values ​​for each indicator, while a negative ideal solution represents the worst combination of values ​​for each indicator. S43. The distance between each coupled system and the positive ideal solution and the negative ideal solution is calculated using Euclidean distance, which is used to measure the relative position of the evaluation object with respect to the optimal and worst states in the multi-index space. S44. Based on the Euclidean distance results, calculate the relative proximity of each evaluation object; S45. Sort the coupling schemes according to their relative proximity to each evaluation object. The coupling scheme with the highest relative proximity value is determined as the optimal scheme. The other coupling schemes are then sorted according to their corresponding ranking results, thus completing the comprehensive evaluation and decision-making under multiple index conditions.

[0015] The multi-dimensional comprehensive performance evaluation system for integrated fire-storage systems adopts the aforementioned multi-dimensional comprehensive performance evaluation method for integrated fire-storage systems. The multi-dimensional comprehensive performance evaluation system for integrated fire-storage systems includes: The model building module is used to build a model of a thermal power unit coupled with a molten salt thermal storage system. The index module is used to select and calculate performance evaluation indexes for coupled systems. The weighting module is used to perform subjective and objective weighting based on the analytic hierarchy process-entropy weighting method to obtain combined weights. The decision-making module is used to calculate the relative proximity of each evaluation object to the positive and negative ideal solutions using the TOPSIS method, thereby enabling comprehensive decision-making under multiple index conditions.

[0016] The computer device includes a processor and a storage medium, the storage medium storing a computer program, which, when executed by the processor, implements the aforementioned multi-dimensional comprehensive performance evaluation method for the combined fire and energy storage system.

[0017] A computer-readable storage medium having a computer program stored thereon, which, when executed, implements the aforementioned multi-dimensional comprehensive performance evaluation method for the combined fire and energy storage system.

[0018] The beneficial effects of the multi-dimensional comprehensive performance evaluation method for coal-fired power plant coupled with molten salt thermal energy storage system of the present invention are as follows: It establishes a dynamic model of the coal-fired power plant coupled with molten salt thermal energy storage system, providing a mathematical basis for describing the dynamic behavior of the system during variable load operation and heat storage / release switching, thus laying the foundation for calculating dynamic performance indicators such as the variable load rate; simultaneously, it introduces both static and dynamic performance indicators to evaluate the coupled system. Based on static indicators such as traditional thermal efficiency, thermal efficiency, and heat storage / release capacity, it further introduces dynamic indicators reflecting the system's rapid response capability, such as the variable load rate, so that the evaluation results can comprehensively reflect the comprehensive performance characteristics of the coupled system during actual operation; it adopts a weight determination method combining subjective and objective approaches, introducing expert experience through the analytic hierarchy process to determine the relative importance of each evaluation indicator, while combining the entropy weight method to objectively assign weights using the information characteristics of the indicator data itself, effectively avoiding biases caused by a single subjective or objective weighting method, improving the scientificity and credibility of the comprehensive evaluation results, and realizing the scientific evaluation and optimization of the comprehensive performance of different coupling schemes, thereby better meeting the needs of engineering practice for selecting coal-fired power plant coupled with molten salt thermal energy storage system schemes. Attached Figure Description

[0019] Figure 1 This is a flowchart of the multi-dimensional comprehensive performance evaluation method for the combined fire and energy storage system according to an embodiment of the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be explained and described below. However, the following embodiments are only preferred embodiments of the present invention and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments in the implementation methods without creative effort are all within the protection scope of the present invention.

[0021] The multi-dimensional comprehensive performance evaluation method for combined fire and energy storage systems according to embodiments of the present invention includes: Step S1: Construct a model of a thermal power unit coupled with a molten salt thermal storage system; Step S2: Select and calculate the performance evaluation index of the coupled system. The performance evaluation index includes static performance index and dynamic performance index. Step S3: Perform subjective and objective weighting based on the analytic hierarchy process (AHP) and entropy weighting method to obtain the combined weights; Step S4: Using the TOPSIS method, calculate the relative closeness of each evaluation object to the positive and negative ideal solutions, achieving comprehensive decision-making under multi-index conditions. TOPSIS (Technique for Order Preference by Similarity to an Ideal Solution) is a ranking method for approximating ideal solutions.

[0022] In step S1, the thermal power unit coupled molten salt thermal storage system model of this embodiment includes a pulverizing system model, a steam-water system model, a steam turbine model, a regenerative system, and a molten salt thermal storage system model.

[0023] The pulverizing system experiences time delays and inertial effects during the process from receiving a fuel quantity command to feeding the fuel into the coal mill, grinding it into pulverized coal, and then delivering it to the boiler. This process affects the amount of fuel in the boiler. r B The calculation expression is: (1) In the formula: u B This indicates the coal feed rate, in kg / s. c 0 represents the inertial time of the powder-making system, in seconds; t Indicates the milling delay time, in seconds. Units include kg / s and s.

[0024] Boiler steam-water systems can be classified into two types according to their structure: drum boilers and once-through boilers. Drum boilers have a steam drum for steam-water separation and storage, providing a certain energy storage and buffering capacity, and are widely used in subcritical and some supercritical units. Once-through boilers, on the other hand, eliminate the steam drum structure, with steam and water flowing along the heating surface in a single pass to complete the heating and evaporation process, making them suitable for high-parameter, large-capacity units. Because the two types of boilers differ significantly in their thermodynamic processes and dynamic characteristics, corresponding mathematical models need to be established to support subsequent system control and optimization design.

[0025] The evaporation system of the steam drum boiler is equipped with a steam drum for the natural separation and storage of steam and water. Its mass conservation and energy conservation equations are as follows: (2) (3) In the formula: r l , rs Let represent the densities of saturated water and saturated vapor, respectively, in kg / s; V l , V s , V t Let m represent the volumes of saturated water, saturated steam, and the total volume of the circulating system, respectively. 3 ; h l , h s These represent the enthalpy values ​​of saturated water and saturated vapor, respectively, in kJ / kg; p D This indicates the pressure in the steam drum, in MPa. C t , M t , T t These represent the specific heat of the circulating system metal, the mass of the metal wall, and the temperature of the water-cooled wall metal, respectively, in kJ / (kg·℃), kg, and ℃; D st , D fw These represent the main steam and feedwater mass flow rates, respectively, in kg / s; h fw , h st These represent the enthalpy values ​​of feedwater and main steam, respectively, in kJ / kg; k 0 represents the boiler furnace fuel quantity coefficient.

[0026] The once-through boiler eliminates the steam drum; feedwater flows sequentially through the economizer, evaporator, and superheater in a single pass, transforming into superheated steam in one continuous flow. Its mass and energy conservation equations are as follows: (4) (5) In the formula: r m This represents the average working fluid pressure at the circulating system point, expressed in kg / s. h m This represents the average point enthalpy of the working fluid in the circulating system, expressed in kJ / kg.

[0027] Based on its working principle and structural characteristics, a steam turbine can be divided into three parts: the regulating stage, the pressure stage, and the final stage. The regulating stage pressure... p g With main steam pressure p st , regulating valve opening i The expression for calculating the relationship between them is: (6) In the formula: k g This represents the gain coefficient of the regulating stage outlet pressure.

[0028] The turbine pressure stage and final stage models are obtained based on the Vlugel formula, and their work processes can be approximated as isentropic processes. i The outlet enthalpy of cylinder number h i The calculation expression is: (7) In the formula: or i express i The isentropic efficiency of cylinder number 1; h iso,i express i The isentropic enthalpy at the outlet of cylinder number 1, kJ / kg.

[0029] Each stage heater in the regenerative system needs to draw a certain amount of steam from each pressure stage to heat the feedwater. i Steam extraction flow rate of cylinder No. 1 D i The magnitude is related to the pressure difference between each stage of the steam turbine and the regenerator, and its calculation expression is: (8) In the formula: k i Indicates the first i Resistance coefficient of the extraction steam pipeline; p i express i Cylinder No. 1 outlet pressure, MPa; p s,i Indicates the first i Saturation pressure of the stage regenerative heater, MPa.

[0030] The high-pressure / low-pressure regenerative heater uses surface heat exchange, and its shell-side and tube-side mass and energy conservation equations are as follows: (9) (10) (11) (12) (13) In the formula: M s,i This indicates the mass of the working fluid on the shell side of the regenerator, in kg; D d,i-1 , D d,i They represent the first i-1 level and i Mass flow rate of the condensate drain from the stage regenerative heater, kg / s; h d,i-1 , h d,i They represent the first i -1 level and i The enthalpy of condensate from the stage regenerative heater, kJ / kg; E s,i , E w,i These represent the total energy of the working fluid on the shell side and tube side of the regenerative heater, respectively, in kJ; D w,i This indicates the mass flow rate of feedwater or condensate on the tube side of the regenerator heater, in kg / s; h w,i+1 , h w,i They represent the first i +1 level and the i Enthalpy values ​​at the inlet and outlet of the feedwater or condensate of the stage regenerative heater, kJ / kg; r l,i , r v,i , h l,i , h v,i They represent the first i Density and enthalpy of saturated water and saturated steam in the stage heater, kg / m³ 3 kJ / kg; V l,i , V v,i , V s,i They represent the first i Saturated water, saturated steam, and total heater volume within the stage heater (m³) 3 ; Q s,i This indicates the heat exchange between the inner tube side and the shell side working fluid of the regenerating heater, expressed in kW. k f This represents the heat transfer coefficient of the regenerative heater, expressed in kW / ℃. T s,i , T w,i , T w,i+1 These represent the heater saturation temperature, the inlet and outlet temperatures of the feedwater or condensate on the pipe side, respectively, in °C.

[0031] The deaerator, acting as a mixing heat exchanger, mixes and exchanges heat between the turbine extraction steam and the condensate from the high-pressure heater and the condensate from the low-pressure heater. Its mass and energy conservation equations are as follows: (14) (15) In the formula: M de , E de These represent the mass of the working fluid and the total energy in the deaerator, respectively, in kg and kJ; D de , D d,de , D w,i , D w,o These represent the mass flow rates of deaerator extraction steam, upper stage condensate, and inlet / outlet feedwater, respectively, in kg / s; h de , h d,de , h w,i , h w,o These represent the enthalpy values ​​of deaerator extraction steam, upper stage condensate, and inlet / outlet feedwater, respectively, in kJ / kg.

[0032] The molten salt heat exchanger model describes the heat exchange process between molten salt and main steam, condensate, or feedwater. The enthalpy of the main steam, condensate, or feedwater after heat exchange is calculated based on the temperature change of the molten salt. The energy conservation equation for the heat exchange process is as follows: (16) (17) (18) (19) In the formula: M ms,hse , M ms,hre , M s,hse , M s,hre These represent the masses of molten salt and working fluid in the molten salt heat exchanger during the heat storage and release stage, respectively, in kg; C p,ms , C p,w These represent the specific heat of molten salt and feedwater or condensate, respectively, in kJ / (kg·℃); T ms,hsei , T ms,hseo , T ms,hrei , T ms,hreo , T w,hrei , Tw,hreo These represent the molten salt inlet and outlet temperatures during the heat storage stage and the molten salt and feedwater or condensate inlet and outlet temperatures during the heat release stage of the molten salt heat exchanger, respectively, in °C; D ms,hse , D ms,hre , D s,hse , D w,hre represents the mass flow rates of molten salt and working fluid during the heat storage and release phase of the molten salt heat exchanger, respectively, in kg / s; Q ms,hse , Q ms,hre These represent the heat exchange between the molten salt and the working fluid during the heat storage and release phase of the molten salt heat exchanger, in kW.

[0033] In step S2, the selected performance indicators include molten salt heat storage and release capacity, coupled system peak shaving performance, variable load rate, and thermodynamic performance. Based on the coupled system model constructed in step S1, the system's heat storage and release capacity, peak shaving capacity, peak shaving depth, variable load rate, and thermodynamic performance (including thermal efficiency, overall thermal efficiency, overall thermal efficiency, and cycle efficiency) under varying operating conditions are calculated.

[0034] The heat storage and release capacity of a coupled system is determined by its heat storage capacity. Q hse Heat release capacity Q hre express: (20) (twenty one) In the formula: C p,ms The specific heat of molten salt is expressed in kJ / (kg·℃). D ms,hse This indicates the mass flow rate of molten salt in the molten salt heat exchanger, in kg / s. D w,hre This indicates the mass flow rate of the working fluid in the molten salt heat exchanger, in kg / s. T ms,hsei , T ms,hseo These represent the inlet and outlet temperatures, respectively, of the molten salt in the molten salt heat exchanger, in K. h w,hrei , h w,hreo These represent the enthalpy values ​​at the inlet and outlet of the working fluid in the molten salt heat exchanger, respectively, in kJ / kg.

[0035] The peak-shaving performance of a coupled system includes peak-shaving capacity and peak-shaving depth. The peak-shaving capacity Δ during the heat storage and release phase... P hse and Δ Phre The calculation expression is: (twenty two) (twenty three) In the formula: P 0、 P e These represent the output power (MW) of the coal-fired unit under 50% THA and 100% THA rated operating conditions, respectively. P hse , P hre These represent the actual output power (MW) of the coupled system during the heat storage and release process. THA (Thermal Heat Acceptance) is the thermal heat rate acceptance condition for thermal power generating units, referring to the standardized operating state under rated parameters for heat consumption assessment.

[0036] Peak Shaving Depth l hse , l hre The calculation expression is: (twenty four) (25) Loading rate of coupled system v The calculation expression is: (26) In the formula: P 0,1 , P 0,2 Let these represent the initial load and target load of the coupled system, respectively, in MW; t 0 indicates that the unit has begun to change load to match the system. P 0,1 , P 0,2 The time required, in min, for the relative deviation between the two sides to be less than 0.1%.

[0037] The thermodynamic performance of a coupled system includes thermal efficiency, thermal efficiency, overall thermal efficiency, overall thermal efficiency, and cycle efficiency. Thermal efficiency during the heat storage and release phase. or Te,hse , or Te,hre The calculation expression is: (27) (28) In the formula: LHV This indicates the lower heating value of coal, in kJ / kg. The lower heating value of standard coal is 29307.6 kJ / kg.m coal,hse , m coal,hse These represent the coal consumption during the heat storage and release stages of the coupled system, in kg / s.

[0038] Overall thermal efficiency or Te,a The calculation expression is: (29) water and steam E w Coal E coal molten salt E ms The calculation expression is: (30) (31) (32) In the formula: h w , s w Let represent the enthalpy and entropy of water and steam, respectively, in kJ / kg and kJ / (kg·K); T 0 represents the reference ambient temperature, in K; h 0、 s 0 represents water and steam in the reference state, respectively. T 0 = 293.15K p Enthalpy and entropy at 0=0.1 MPa, kJ / kg, kJ / (kg·K); m w、 m ms、 m coal These represent the mass flow rates of water and steam, molten salt and coal, respectively, in kg / s; T ms The temperature of the molten salt is expressed in K. oh ( C ), oh ( H ), oh ( O ), oh ( N The numbers () represent the mass fractions of carbon, hydrogen, oxygen, and nitrogen in coal, respectively.

[0039] Efficiency of the heat storage and release stage of the coupled system or Ex,hse , or Ex,hre The calculation expression is: (33) (34) In the formula: E ms,cold , E ms,hot These represent the volume (e) and power (kW) of hot and cold molten salt, respectively. E coal,hse , E coal,hse These represent the heat output of coal during the heat storage and release stage, in kWh and kW, respectively.

[0040] Overall efficiency or Ex,a The calculation expression is: (35) Cyclic efficiency of coupled systems or rt The calculation expression is: (36) In the formula: t hse , t hse and represent the heat storage and release times of the coupled system, in seconds.

[0041] In most engineering practices, different coupling schemes often exhibit differences in peak-shaving capability, thermal performance, and energy utilization level. In such cases, directly comparing performance indicators is insufficient to provide a reasonable and comprehensive evaluation of the overall system performance. To fully leverage the performance advantages of the coupled system and balance multi-dimensional performance indicators, it is necessary to conduct a comprehensive multi-dimensional performance evaluation. In step S3, First, subjective weighting is performed, and the specific steps are as follows: Establish a hierarchical structure. Based on the logical relationship between the evaluation objectives and the indicator system, construct a hierarchical model consisting of an "objective layer, criterion layer, and scheme layer." The objective layer represents the overall evaluation objective, namely, selecting the optimal heat storage and release coupling scheme; the indicator layer consists of the obtained evaluation indicators; and the scheme layer consists of different heat storage and release schemes for the coupling system to be evaluated.

[0042] Based on expert experience, the importance of each indicator at the same level relative to the target at the next higher level is compared pairwise, and a judgment matrix is ​​constructed using the nine-level scaling method shown in Table 1. A : (37) In the formula: a ij Indicates the first i The performance index is relative to the first j The importance scale of each performance metric, and satisfies: (38) Table 1

[0043] Calculate the subjective weights. For the judgment matrix... A Perform eigenvalue decomposition and find its largest eigenvalue. l max The corresponding feature vectors are obtained, and the feature vectors are normalized to obtain the subjective weights of each indicator: (39) In the formula: oh AHP，j Indicates the first j Subjective weights of each evaluation indicator.

[0044] To ensure the rationality of the judgment matrix, a consistency check is performed. First, the consistency index is calculated: (40) Recalculate the consistency ratio: (41) In the formula: CI Indicates a consistency index; CR Indicates the consistency ratio; RI This represents a random consistency index. When... CR When the value is less than 0.1, the judgment matrix is ​​considered to meet the consistency requirement, and the subjective weights are considered valid. RI The possible values ​​are shown in Table 2: Table 2

[0045] Next, objective weighting is performed, and the specific steps are as follows: Calculate the evaluation index values ​​for each coupling scheme, and construct the decision matrix accordingly: (42) In the formula: x ij Indicates the first i The evaluation object is in the first j The values ​​for each indicator.

[0046] To eliminate the influence of dimensions, the data in the decision matrix is ​​standardized: (43) In the formula: z ij The standardized decision matrix is ​​represented by the first... i The evaluation object is in the first jThe values ​​for each indicator are standardized to make the data from different indicators comparable, providing a unified data foundation for subsequent information entropy calculations.

[0047] Based on the standardized decision matrix, the information entropy of each indicator is calculated. First, the weight of each indicator under different evaluation objects is calculated. p ij : (44) Calculate the next Information entropy of each indicator e j : (45) Calculate the objective weight of each evaluation indicator based on its information entropy value. oh EWM : (46) Objective weights reflect the relative importance of each indicator based on the actual data distribution, avoiding the singular influence of subjective human factors on weight allocation.

[0048] Finally, the geometric mean method is used to combine subjective and objective weights to obtain the combined weight. oh mix : (47)

[0049] In step S4, after obtaining the final combined weights of each evaluation index, the TOPSIS method is used to achieve comprehensive ranking of each evaluation object and selection of the optimal solution. This method calculates the relative proximity of each evaluation object to the positive and negative ideal solutions, thus enabling comprehensive decision-making under multi-index conditions. The specific steps are as follows: Construct a weighted decision matrix. This is based on the standardized decision matrix constructed in step three and the combined weights of each evaluation indicator. oh mix The decision matrix is ​​weighted to obtain the weighted decision matrix. V : (48) Based on the weighted decision matrix, construct the positive ideal solution respectively. V + and negative ideal solution V - A positive ideal solution represents the optimal combination of values ​​for each indicator, while a negative ideal solution represents the worst combination of values ​​for each indicator. (49) (50) (51) The Euclidean distance is used to calculate the distances between each coupled system and the positive and negative ideal solutions, respectively, to measure the relative position of the evaluation object with respect to the optimal and worst states in the multi-index space. The expressions for calculating the distances between each coupled system and the positive and negative ideal solutions are as follows: (52) (53) Based on the above distance results, the relative proximity of each evaluation object is calculated: (54) In the formula: C i The greater the relative proximity (∈[0,1]), the closer the coupling scheme is to the positive ideal solution, and the better its overall performance.

[0050] Comprehensive ranking and selection of the optimal solution. Based on the relative similarity of each evaluated object. C i Sort them. C i The coupling scheme with the largest value is determined as the optimal scheme, and the remaining coupling schemes are ranked accordingly, thus completing the comprehensive evaluation and decision-making under multiple index conditions.

[0051] To further illustrate the superiority of the multi-dimensional comprehensive performance evaluation method for the combined fire and energy storage system in this embodiment compared with existing methods, the following describes the scheme selection for a specific combined fire and energy storage system project.

[0052] The project is planned to include a 600MW coal-fired power unit and a 90MW thermal storage unit. The thermal storage medium is a ternary mixed nitrate HTS (53% KNO3-40% NaNO2-7% NaNO3).

[0053] The alternative coupling schemes are shown in the table below.

[0054]

[0055] The performance indicators for each scheme are calculated and shown in the table below.

[0056]

[0057] 1. Key indicators for the thermal storage stage.

[0058] Peak shaving performance: As shown in the table above, the B1 scheme is the best, with a peak shaving capacity of 43.01MW and a peak shaving depth of 7.16%, which is significantly higher than B2 (30.74MW / 5.12%) and B3 (34.76MW / 5.8%). This is because the main steam can simultaneously affect the output of the high, medium and low pressure cylinders, resulting in a wider adjustment range.

[0059] Thermodynamic performance: Scheme B2 has the highest thermal efficiency (44.18%), while Scheme B1 has a thermal efficiency of 42.67% (due to the high energy grade of the main steam, resulting in slightly greater energy loss after extraction); In terms of thermal efficiency, Scheme B1 has 36.40%, which is higher than that of hot water storage, because molten salt has a high thermal density and low energy grade loss.

[0060] 2. Key indicators during the heat release phase.

[0061] Peak shaving performance: As shown in the table above, scheme b1 is the best, with a peak shaving capacity of 26.09MW and a peak shaving depth of 4.35%, which far exceeds b2 (25.42MW / 4.23%) and b3 (15.40MW / 2.56%). This is because the condensate inlet of #2 high-pressure heater is close to the boiler feedwater side, with high water temperature and sufficient water volume, which can reduce the steam extraction of the high-pressure heater and increase the turbine flow rate.

[0062] Thermodynamic performance: Scheme b1 has the best thermal efficiency (39.83%) and heat transfer efficiency (40.96%) among the three heat release schemes; Scheme b3 has the lowest thermal efficiency and heat transfer efficiency due to the low energy grade of the condensate added at the bottom and the large heat transfer loss.

[0063] 3. Comprehensive evaluation (TOPSIS method).

[0064] The scores for each candidate scheme are shown in the table below.

[0065]

[0066] The optimal coupling scheme is B1-b1 (main steam is the heat source, and the #2 high-pressure heater condensate inlet is the cold source), with a normalized score of 0.60. It has the best overall performance among the four indicators of peak-shaving capacity, peak-shaving depth, thermal efficiency, and thermal efficiency.

[0067] Scheme ranking: B1-b1 > B3-b3 > B2-b2. Although the thermal efficiency of scheme B1-b1 is slightly lower than that of B2 in the heat storage stage, it has a significant advantage in peak shaving capability and the best thermodynamic performance in the heat release stage, which meets the core needs of power grid peak shaving.

[0068] Therefore, the optimal application scheme for a 600MW coal-fired power unit coupled with a 90MW molten salt thermal storage system is the B1-b1 scheme (main steam thermal storage + #2 high-pressure heater condensate inlet heat release). This scheme performs best in terms of the comprehensive balance between peak-shaving capacity and thermodynamic performance, and can be the preferred choice for coal-fired power molten salt thermal storage peak-shaving projects.

[0069] The beneficial effects of the multi-dimensional comprehensive performance evaluation method for the combined fire and energy storage system in this embodiment include: 1. Establish a dynamic model of a coal-fired unit coupled with a molten salt thermal storage system. A unified model is constructed for the pulverizing system, boiler steam-water system, turbine system, regenerative system, and molten salt thermal storage system. This provides a mathematical basis for describing the dynamic behavior of the system during variable load operation and heat storage-release switching, thus laying the foundation for calculating dynamic performance indicators such as the variable load rate.

[0070] 2. At the same time, static and dynamic performance indicators are introduced to evaluate the coupled system. In addition to traditional static indicators such as thermal efficiency, heat efficiency, and heat storage and release capacity, dynamic indicators such as variable load rate, which reflect the system's rapid response capability, are further introduced so that the evaluation results can comprehensively reflect the overall performance characteristics of the coupled system in actual operation.

[0071] 3. Construct a comprehensive performance evaluation system covering multiple evaluation indicators. Systematically evaluate the comprehensive performance of different coal-fired units coupled with molten salt thermal energy storage schemes from multiple evaluation dimensions such as heat storage and release capacity, peak-shaving performance, dynamic response characteristics and thermal performance, so as to realize performance comparison and optimization under multiple scheme conditions.

[0072] 4. A weighting method combining subjective and objective approaches is adopted. The relative importance of each evaluation indicator is determined by introducing expert experience through the analytic hierarchy process. At the same time, the entropy weighting method is combined to objectively assign weights using the information characteristics of the indicator data itself. This effectively avoids the bias caused by a single subjective or objective weighting method and improves the scientificity and credibility of the comprehensive evaluation results.

[0073] This invention also provides a multi-dimensional comprehensive performance evaluation system for integrated fire-storage systems, employing the aforementioned multi-dimensional comprehensive performance evaluation method for integrated fire-storage systems. The multi-dimensional comprehensive performance evaluation system for integrated fire-storage systems includes: The model building module is used to build a model of a thermal power unit coupled with a molten salt thermal storage system. The index module is used to select and calculate performance evaluation indexes for coupled systems. The weighting module is used to perform subjective and objective weighting based on the analytic hierarchy process-entropy weighting method to obtain combined weights. The decision-making module is used to calculate the relative proximity of each evaluation object to the positive and negative ideal solutions using the TOPSIS method, thereby enabling comprehensive decision-making under multiple index conditions.

[0074] This invention also provides a computer device, including a processor and a storage medium, wherein the storage medium stores a computer program, and when the computer program is executed by the processor, it implements the aforementioned multi-dimensional comprehensive performance evaluation method for a combined fire and energy storage system.

[0075] This invention also provides a computer-readable storage medium storing a computer program thereon, which, when executed, implements the aforementioned multi-dimensional comprehensive performance evaluation method for combined fire and energy storage systems.

[0076] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes, but is not limited to, the content described in the above specific embodiments. Any modifications that do not depart from the functional and structural principles of the present invention will be included within the scope of the claims.

Claims

1. A multi-dimensional comprehensive performance evaluation method for combined fire and energy storage systems, characterized by: The multi-dimensional comprehensive performance evaluation method for the combined fire and energy storage system includes: Step S1: Construct a model of a thermal power unit coupled with a molten salt thermal storage system; Step S2: Select and calculate the performance evaluation index of the coupled system. The performance evaluation index includes static performance index and dynamic performance index. Step S3: Perform subjective and objective weighting based on the analytic hierarchy process (AHP) and entropy weighting method to obtain the combined weights; Step S4: Using the TOPSIS method, calculate the relative proximity between each evaluation object and the positive and negative ideal solutions to achieve comprehensive decision-making under multiple index conditions.

2. The multi-dimensional comprehensive performance evaluation method for a combined fire and energy storage system according to claim 1, characterized in that: In step S1, the thermal power unit coupled molten salt thermal storage system model includes a pulverizing system model, a steam-water system model, a steam turbine model, a regenerative system model, and a molten salt thermal storage system model.

3. The multi-dimensional comprehensive performance evaluation method for a combined fire and energy storage system according to claim 1, characterized in that: In step S2, the selected performance evaluation indicators include molten salt heat storage and release capacity, peak shaving performance, load increase rate, and thermal performance.

4. The multi-dimensional comprehensive performance evaluation method for a combined fire and energy storage system according to claim 3, characterized in that: Molten salt heat storage and release capacity is measured by heat storage capacity. Q hse Heat release capacity Q hre express: (20) (21) In the formula: C p,ms The specific heat of molten salt is expressed in kJ / (kg·℃). D ms,hse This indicates the mass flow rate of molten salt in the molten salt heat exchanger, in kg / s. D w,hre This indicates the mass flow rate of the working fluid in the molten salt heat exchanger, in kg / s. T ms,hsei , T ms,hseo These represent the inlet and outlet temperatures, respectively, of the molten salt in the molten salt heat exchanger, in K. h w,hrei , h w,hreo These represent the enthalpy values ​​at the inlet and outlet of the working fluid in the molten salt heat exchanger, respectively, in kJ / kg; Peak-shaving performance is expressed by peak-shaving capacity and peak-shaving depth. The peak-shaving capacity Δ during the heat storage and release stage is... P hse and Δ P hre The calculation expression is: (22) (23) In the formula: P 0、 P e These represent the output power (MW) of the coal-fired unit under 50% THA and 100% THA rated operating conditions, respectively. P hse , P hre They represent the actual output power of the coupled system during the heat storage and release process, in MW; Peak Shaving Depth λ hse , λ hre The calculation expression is: (24) (25) Load increase rate v The calculation expression is: (26) In the formula: P 0,1 , P 0,2 Let these represent the initial load and target load of the coupled system, respectively, in MW; t 0 indicates that the unit has begun to change load to match the system. P 0,1 , P 0,2 The time required, in minutes, for the relative deviation between the two values ​​to be less than 0.1%. Thermal performance includes thermal efficiency, thermal efficiency, overall thermal efficiency, overall thermal efficiency, and cycle efficiency.

5. The multi-dimensional comprehensive performance evaluation method for a combined fire and energy storage system according to claim 1, characterized in that: Step S3 includes: S31. First, subjective empowerment is carried out: S32. Secondly, objective weighting is carried out; S33. Finally, the geometric mean method is used to combine subjective weights and objective weights to obtain the combined weights.

6. The multi-dimensional comprehensive performance evaluation method for a combined fire and energy storage system according to claim 5, characterized in that: In S31, the subjective empowerment process includes: Based on the logical relationship between the evaluation objectives and the indicator system, a hierarchical structure model consisting of "objective layer - indicator layer - solution layer" is constructed. Based on expert experience, a judgment matrix is ​​constructed to compare the importance of each indicator at the same level relative to the target at the next higher level. The judgment matrix is ​​decomposed into eigenvalues ​​to find its largest eigenvalue and corresponding eigenvector, and the eigenvector is normalized to obtain the subjective weights of each indicator. Perform a consistency check; In S32, the objective weighting process includes: Construct a decision matrix; Standardize the data in the decision matrix; Based on the standardized decision matrix, the information entropy of each indicator is calculated. Calculate the objective weight of each evaluation indicator based on its information entropy value.

7. The multi-dimensional comprehensive performance evaluation method for a combined fire and energy storage system according to claim 6, characterized in that: Step S4 includes: S41. Construct a weighted decision matrix; S42. Based on the weighted decision matrix, construct the positive ideal solution and the negative ideal solution respectively. ， A positive ideal solution represents the optimal combination of values ​​for each indicator, while a negative ideal solution represents the worst combination of values ​​for each indicator. S43. The distance between each coupled system and the positive ideal solution and the negative ideal solution is calculated using Euclidean distance, which is used to measure the relative position of the evaluation object with respect to the optimal and worst states in the multi-index space. S44. Based on the Euclidean distance results, calculate the relative proximity of each evaluation object; S45. Sort the coupling schemes according to their relative proximity to each evaluation object. The coupling scheme with the highest relative proximity value is determined as the optimal scheme. The other coupling schemes are then sorted according to their corresponding ranking results, thus completing the comprehensive evaluation and decision-making under multiple index conditions.

8. A multi-dimensional comprehensive performance evaluation system for combined fire and energy storage systems, characterized in that: The multi-dimensional comprehensive performance evaluation method for the combined fire and energy storage system according to any one of claims 1 to 7 is adopted, wherein the multi-dimensional comprehensive performance evaluation system for the combined fire and energy storage system includes: The model building module is used to build a model of a thermal power unit coupled with a molten salt thermal storage system. The index module is used to select and calculate performance evaluation indexes for coupled systems. The weighting module is used to perform subjective and objective weighting based on the analytic hierarchy process-entropy weighting method to obtain combined weights. The decision-making module is used to calculate the relative proximity of each evaluation object to the positive and negative ideal solutions using the TOPSIS method, thereby enabling comprehensive decision-making under multiple index conditions.

9. A computer device, comprising a processor and a storage medium, wherein the storage medium stores a computer program, characterized in that: When the computer program is executed by the processor, it implements the multi-dimensional comprehensive performance evaluation method for the combined fire and energy storage system as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: It stores a computer program, which, when executed, implements the multi-dimensional comprehensive performance evaluation method for the combined fire and energy storage system as described in any one of claims 1 to 7.

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