Solar energy heating efficiency increasing method and system of micro-channel flat-plate collector

Abstract

The present application relates to solar heating operation control technical field, especially to a kind of solar heating efficiency increasing method and system of microchannel flat-plate collector.The present application establishes state condition acoustic emission background database dynamically adjusted with solar irradiance, inlet temperature, total mass flow and collector pressure difference, constructs nonlinear acoustic emission state index by fusing local abnormal degree of effective acoustic emission event and adjacent detection area space-time aggregation characteristics, obtains the ability of accurately identifying pre-critical state and triggering local intervention before continuous delamination of interlayer connection interface detection calibration critical threshold.The present application can only implement local heat transfer fluid flow regulation of pressure safety constraint to the microchannel group mapped by detection area entering pre-critical state, reduce the flow variation of normal area, reduce circulating pump energy consumption under the premise of improving net heating energy.

Description

Technical Field

[0001] This invention relates to the field of solar heating operation control technology, and in particular to a method and system for enhancing the efficiency of solar heating using a microchannel flat plate collector. Background Technology

[0002] During the long-term operation of microchannel flat plate solar collectors, the interlayer connection interface between the absorber plate and the microchannel support layer will repeatedly undergo differential thermal deformation due to fluctuations in solar irradiance, changes in inlet temperature, and diurnal thermal cycling, gradually forming dispersed micro-misfit areas. Existing technologies rely on macroscopic operating parameters such as solar irradiance, collector inlet and outlet temperatures, total mass flow rate, and storage device temperature to determine the system status and adjust the heating supply. However, when the micro-misfit areas are still in the early stage, with small areas and dispersed from each other, they are still surrounded by large, intact connection areas, and the impact on the overall collector outlet temperature and effective heat output is not obvious. Macroscopic parameters cannot directly reflect the process of micro-misfit evolving from a dispersed state to an aggregated state within the interlayer connection interface. This early structural degradation is insidious and cumulative, and is not easily detected before the local temperature accumulation and significant increase in heat loss at the interface. When the misfit areas connect to form continuous misfits, the heat from the local absorber plate cannot be transferred to the heat transfer fluid in a timely manner, and the effective heating capacity will decrease irreversibly.

[0003] The method of cooling intervention by increasing the overall heat transfer fluid flow rate lacks the ability to distinguish between abnormal and normal regions at the interlayer interface, which can easily lead to unnecessary flow changes in normal regions and increase the energy consumption of the circulating pump. At the same time, existing acoustic emission monitoring methods only make judgments based on the absolute number of acoustic emission events and fixed thresholds, without taking into account the influence of solar irradiance, inlet temperature, total mass flow rate, and collector pressure difference on the acoustic emission background, making the judgment results susceptible to interference from changes in operating conditions. Furthermore, existing methods lack the means to jointly model the temporal anomaly of acoustic emission activity, the spatiotemporal aggregation relationship between adjacent detection areas, and the current thermal operating state, making it difficult to identify the pre-critical state before a significant continuous loss of adhesion forms at the interlayer interface. Summary of the Invention

[0004] To overcome the shortcomings of insufficient interface degradation control in microchannel flat plate solar collectors, this invention provides a method and system for enhancing the solar heating efficiency of microchannel flat plate solar collectors.

[0005] The technical implementation scheme of the present invention is as follows: a method for improving the solar heating efficiency of a microchannel flat plate solar collector, comprising the following steps:

[0006] S1: Establish a synchronous acquisition system for microchannel local connection areas, operating status parameters, acoustic emission signals, local temperature and fluid operation parameters, and establish a device parameter database and detection area topology;

[0007] S2: Under normal conditions, establish a state condition acoustic emission background database based on the operating state vector, extract effective acoustic emission events and construct spatiotemporal clustering features, and construct nonlinear acoustic emission state indices.

[0008] S3: Establish a calibration relationship between nonlinear acoustic emission state index and critical state of interlayer connection interface using interlayer connection interface, and identify the pre-critical state of interlayer connection interface online.

[0009] S4: Implement constrained local heat transfer fluid flow rate regulation for the microchannel group mapped to the detection area corresponding to the pre-critical state, and perform closed-loop control;

[0010] S5: Evaluate the changes in effective heating energy, heat collection efficiency, pump energy consumption, net heating energy and acoustic emission status indicators before and after adjustment under operating conditions, and update the acoustic emission background database under operating conditions.

[0011] Preferably, the establishment of a synchronous acquisition system for microchannel local connection regions, operating status parameters, acoustic emission signals, local temperature, and fluid operating parameters, and the establishment of a device parameter database and detection area topology, includes: dividing the interlayer connection interface along the microchannel arrangement direction into... Each detection area corresponds to a microchannel group formed by adjacent microchannels, establishing a fixed mapping relationship between the detection areas and the microchannel groups; an acoustic emission sensor is set in each detection area to collect the raw acoustic emission voltage signal. Local heat absorber temperature sensors are installed on the surface of the heat absorber in each detection area to collect the local heat absorber temperature. Collect the inlet temperature of the solar collector. collector outlet temperature Total mass flow rate Local microchannel mass flow rate Collector pressure difference Pressure difference between the two ends of the circulating pump Solar irradiance Ambient temperature Obtain the density of the heat transfer fluid. Specific heat capacity of heat transfer fluid Circulating pump efficiency Effective light-receiving area of ​​the solar collector Establish an adjacency matrix for the detection region. ,in Indicates the first The detection area and the first Adjacent detection areas Indicates the first The detection area and the first The detection areas are not adjacent.

[0012] Preferably, the step of establishing a state-conditional acoustic emission background database based on the operating state vector under normal conditions includes: defining the operating state vector. ,in , , , ; This is a reference value for solar irradiance. This is a reference value for temperature difference. This is a reference value for total mass flow rate. The collector pressure differential reference value is used; during the operating cycle where independent testing confirms that the interlayer connection interface is in a normal state, the initial valid acoustic emission events are extracted using preset initial acoustic emission event identification rules, and the statistical time window is calculated. Initial effective acoustic emission event rate within Logarithmic transformation of the initial effective acoustic emission event rate is given by the following formula: ,in This is the logarithmic transformation value of the initial effective acoustic emission event rate. To prevent positive values ​​with a logarithm of zero from being corrected, the operating state vector obtained from the normal operating cycle will be used as the correction parameter. Initial effective acoustic emission event rate Logarithmic transformation value of the initial effective acoustic emission event rate Store the acoustic emission background database to form state conditions; obtain the current running state. The first in the state-condition acoustic emission background database The running state vector of a normal sample Normalized distance between ; Calculate nonlinear kernel weights The formula is: ,in The state neighborhood scale parameter, The number of normal samples used in the calculation. Indicates the current running status With the The running state vector of a normal sample The normalized distance between them is obtained using the same distance calculation method; nonlinear kernel weights are used. Calculate the logarithmic baseline of the normal event rate Dispersion with normal state The calculation formula is: and ; Calculate the acoustic emission background reference under state conditions When the calculation result is less than zero, Set it to zero.

[0013] Preferably, the extraction of valid acoustic emission events and the construction of spatiotemporal clustering features include: based on the logarithm of the normal event rate. Dispersion with normal state Build dynamic event trigger thresholds The formula is: ,in Background deviation control coefficient; for the original acoustic emission voltage signal After bandpass filtering, removal of fixed-frequency mechanical vibration components, and amplitude normalization, the amplitude of the original acoustic emission voltage signal exceeds the dynamic event triggering threshold. When the minimum duration, maximum duration, and event dead time requirements are met, the signal segment is defined as a valid acoustic emission event; the current time window is statistically analyzed. Inner The set of valid acoustic emission events in a detection area and current effective event rate ; Calculate the standardized outliers of the state The formula is: ,in It is a dimensionless stable term; calculate the event-time synergy between adjacent detection regions. and normalized synergy The formula is and ;in For event time coordination window, It is a dimensionless stable term; obtain the first term. The detection area and the first Spatial distance between the centers of each detection area Spatial weights are constructed using the adjacency matrix and spatial distance between detection regions. The formula is: ,in For spatial correlation scale; calculate spatiotemporal clustering factor The formula is: ,in For the first The set of adjacent detection regions of a detection region.

[0014] Preferably, constructing the nonlinear acoustic emission state index includes: standardizing the state anomalies. Convert to non-negative smoothed risk The formula is: ,in Dimensionless shape coefficients; construct spatiotemporal co-enhancing terms The formula is: ,in For the nonlinear coefficients of the spatiotemporal coordination enhancement term, The exponent for spatiotemporal coordination enhancement; constructing nonlinear interaction terms. The formula is: ,in For nonlinear interaction term coupling coefficients, The exponent of the nonlinear interaction term is obtained; Nonlinear acoustic emission state index of each detection area The formula is: .

[0015] Preferably, the step of establishing the calibration relationship between the nonlinear acoustic emission state index and the critical state of the interlayer connection interface using the interlayer connection interface includes: preparing a calibration microchannel flat plate solar collector with the same material combination, microchannel structure, interlayer connection process, and sensor arrangement as the microchannel flat plate solar collector to be monitored; applying thermal cycling conditions to the calibration microchannel flat plate solar collector and simultaneously collecting data; and calculating the nonlinear acoustic emission state index of the calibration microchannel flat plate solar collector. During the preset thermal cycling phase, the thermal cycling operation is stopped, and the area of ​​micro-misfit is obtained using industrial CT. Total area of ​​interlayer connection interfaces and the area of ​​the largest continuous misfit region ; Calculate the proportion of micro-misfit area and micro-disconnection connectivity The formula is: and , The parameter is a positive correction parameter; based on the preset area critical value. and connectivity threshold Determine the calibration stage for the critical state of continuous mis-adhesion, when the proportion of micro-mis-adhesion area... Greater than or equal to the preset area threshold value And slight disconnection connectivity Greater than or equal to the critical value of connectivity At that time, the corresponding thermal cycle stage is determined as the continuous misalignment critical state calibration stage; the calibration corresponding to the continuous misalignment critical state calibration stage is performed using the nonlinear acoustic emission state index of the microchannel flat plate collector. Recorded as a critical index for continuous loss of interest Establish normalized critical process variables The formula is: ,in To establish a benchmark for the nonlinear acoustic emission performance of microchannel flat-plate solar collectors for calibration. This is a dimensionless stable term; based on the normalized critical process variable of the microchannel flat plate solar collector before the calibration stage of continuous misalignment critical state. The statistical distribution selects the pre-critical proportion Obtaining pre-critical indicators The calculation formula is: Statistical calibration of microchannel flat plate solar collectors during the pre-critical state The statistical distribution of the rate of change yields the maximum permissible state growth rate. ;Will The rate of change continuously exceeds the maximum permissible rate of increase. Furthermore, a state exhibiting an accelerating growth trend is defined as a rapid development state. This rapid development state... The statistical threshold of the rate of change as a threshold for rapid development ,Will , , , Store it.

[0016] Preferably, the online identification of the pre-critical state of the inter-layer connection interface includes: real-time acquisition of the first... Nonlinear acoustic emission state index of each detection area ; Calculate short-period changes and long-term changes The calculation formula is: and ;in For the current time, To calculate a longer time window for short-cycle calculations, For long-period calculations, the time window is long. ; Calculate trend consistency The formula is: ,in A dimensionless stable term; construct a nonlinear evolution factor. The formula is: ,in It is a dimensionless state scale parameter. The coefficient is a dimensionless coupling coefficient; when and and At that time, the judgment of the first Each detection area enters a pre-critical state; when Time to determine the first Each detection area enters a critical state of continuous loss of adhesion; when Maintain normal monitoring status; when but It was determined to be in a high-level stable state.

[0017] Preferably, the step of implementing constrained local heat transfer fluid flow rate regulation for the microchannel group mapped to the detection region corresponding to the pre-critical state, and performing closed-loop control, includes: obtaining the basic mass flow rate of the microchannel group corresponding to the detection region entering the pre-critical state. Define the criticality variable. The formula is: ; Calculate the temperature change state of the local heat absorber plate The formula is: ,in For the first The surface temperature of the heat absorber plate at the corresponding location of each detection area. Establish a calculation window for temperature changes; construct dimensionless thermal state variables. The formula is: ,in This is a normal temperature change scale. It is a dimensionless stable term; calculate the pressure safety margin. The calculation formula is: ,in The maximum allowable pressure difference for the solar collector. It is a dimensionless stable term; calculate the local flow increment. The formula is: ,in To maximize traffic increment, This is the criticality weighting coefficient. This is the thermal state weighting coefficient. For the critical degree of nonlinearity, The thermal nonlinearity index is used to calculate the target local mass flow rate. ,in For the target local mass flow rate, and These represent the minimum and maximum allowable mass flow rates for the local microchannel group, respectively; based on the temperature change state of the local absorber plate and Make feedback and adjustments when and When economic activity resumes, when and At this time, it is permissible to continue increasing the local flow rate under pressure safety constraints, when Stop modifying local flow at a certain time; The upper limit of normal temperature variation is the economic operating flow rate, which is the recommended flow rate with the lowest energy consumption. As a safe threshold for the rate of temperature decrease, the Economic operating flow and Retrieved from the device parameter database; when Stop increasing the local flow when the time comes; When an anomaly occurs, it should be handled accordingly.

[0018] Preferably, the step of evaluating changes in effective heating energy, heat collection efficiency, pump energy consumption, net heating energy, and acoustic emission state indicators before and after adjustment under operating condition matching, and updating the state condition acoustic emission background database, includes: calculating effective heat power. The formula is: ; Calculate the heat collection efficiency The formula is: Heat collection efficiency exist Calculated within the evaluation range, Calculate the minimum effective irradiance threshold; calculate the input power of the circulating pump. The formula is: , Calculate the net effective heating power. The formula is: Construct the running state vectors before and after adjustment and calculate the running state distance, selecting only those with a running state distance less than or equal to... The evaluation is conducted within a specific time window. Set a threshold for allowed running states; define a matching window. The distance between the operating states before and after adjustment is less than or equal to A continuous time window; in the matching window Internal calculation of effective thermal energy Pump energy consumption The formula is and Calculate net heating energy The formula is: Define the net heating efficiency coefficient. The formula is: , A positive energy stabilization term; define the acoustic emission state improvement coefficient. The formula is: ,in To adjust the mean value of the acoustic emission state index, To adjust the mean values ​​of the front acoustic emission state parameters; a local temperature change improvement coefficient is defined. The formula is: ,in To adjust the average temperature change of the local heat absorber plate after adjustment, To adjust the average temperature change of the local heat absorber plate; when simultaneously satisfying , or The continued growth trend has been suppressed. If the preset net heating maintenance ratio is achieved and the local flow limit and pressure safety limit are not exceeded during the control period, the corresponding operating cycle of this adjustment will be marked as an effective control cycle; only data that meets the normal state requirements within a continuous time window will be marked as normal background candidate data, using exponential decay weighting. Update the state condition acoustic emission background database. The calculation formula is: , The time interval between the sample and the current time. Update the time scale for the background.

[0019] Preferably, a solar heating efficiency enhancement system for a microchannel flat plate collector further includes:

[0020] The synchronous acquisition and topology construction module is used to establish a synchronous acquisition system for microchannel local connection areas, operating status parameters, acoustic emission signals, local temperature and fluid operation parameters, and to establish a device parameter database and topological relationships of the detection area;

[0021] The acoustic emission background and index module is used to establish a state-condition acoustic emission background database based on the operating state vector under normal conditions, extract effective acoustic emission events and construct spatiotemporal clustering features, and construct nonlinear acoustic emission state indices.

[0022] The pre-critical state identification module is used to establish a calibration relationship between the nonlinear acoustic emission state index and the critical state of the interlayer connection interface using the interlayer connection interface, and to identify the pre-critical state of the interlayer connection interface online.

[0023] The local flow closed-loop control module is used to implement constrained local heat transfer fluid flow regulation for the microchannel group mapped to the detection area corresponding to the pre-critical state, and to perform closed-loop control.

[0024] The heating efficiency evaluation and update module is used to evaluate changes in effective heating energy, heat collection efficiency, pump energy consumption, net heating energy, and acoustic emission status indicators before and after adjustment under operating conditions, and to update the acoustic emission background database under the conditions.

[0025] Beneficial effects: This invention establishes a dynamic acoustic emission background database that varies with solar irradiance, inlet temperature, total mass flow rate, and collector pressure difference, allowing the normal acoustic emission benchmark to adaptively adjust with operating conditions, thus suppressing misjudgments of interlayer connection interfaces caused by changes in operating conditions from the source. By fusing the local anomaly degree of effective acoustic emission events with the temporal synchronization degree and spatial distance of adjacent detection areas into a nonlinear acoustic emission state index, the early concealed characteristics of micro-deadlock evolution from dispersion to connectivity are amplified. By establishing a calibration relationship between the nonlinear acoustic emission state index and the micro-deadlock area ratio and connectivity degree through interlayer connection interface detection, the pre-critical state can be identified online, achieving a leap from macroscopic heating performance judgment to early interface degradation identification without continuous imaging. After identifying the pre-critical state, based on the critical degree and local absorber plate temperature... The method calculates bounded local flow increments based on temperature change status and collector pressure safety margin, adjusting the local heat transfer fluid flow only for microchannel groups corresponding to abnormal detection areas. This, combined with local temperature and acoustic emission status feedback, forms a closed loop, enabling the control path to dynamically switch based on the error sources at the interlayer connection interface. The adjustment effect is evaluated by changes in net heating energy, collector efficiency, pump energy consumption, and acoustic emission status indicators under operating condition matching. Only data filtered for normal conditions is used to update the acoustic emission background database under conditional conditions, avoiding abnormal data contaminating the normal baseline. The method, from operational conditional error identification to spatiotemporal aggregation state modeling, offline critical calibration, and local closed-loop control path switching, forms a coupled mechanism that directly drives control path switching from error source identification, intervening before continuous misalignment occurs and improving the effective solar heating capacity. Attached Figure Description

[0026] Figure 1 This is a flowchart of a method for improving the efficiency of solar heating using a microchannel flat plate solar collector according to the present invention.

[0027] Figure 2 This is a schematic diagram of the solar heating efficiency enhancement system of a microchannel flat plate collector according to the present invention. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1: A method for enhancing the solar heating efficiency of a microchannel flat plate collector, such as... Figure 1 As shown, it includes the following steps:

[0030] S1: Establish a synchronous acquisition system for microchannel local connection areas, operating status parameters, acoustic emission signals, local temperature and fluid operation parameters, and establish a device parameter database and detection area topology;

[0031] S2: Under normal conditions, establish a state condition acoustic emission background database based on the operating state vector, extract effective acoustic emission events and construct spatiotemporal clustering features, and construct nonlinear acoustic emission state indices.

[0032] S3: Establish a calibration relationship between nonlinear acoustic emission state index and critical state of interlayer connection interface using interlayer connection interface, and identify the pre-critical state of interlayer connection interface online.

[0033] S4: Implement constrained local heat transfer fluid flow rate regulation for the microchannel group mapped to the detection area corresponding to the pre-critical state, and perform closed-loop control;

[0034] S5: Evaluate the changes in effective heating energy, heat collection efficiency, pump energy consumption, net heating energy and acoustic emission status indicators before and after adjustment under operating conditions, and update the acoustic emission background database under operating conditions.

[0035] The interlayer connection interface is divided along the microchannel arrangement direction into... Each detection area corresponds to a microchannel group formed by adjacent microchannels, establishing a fixed mapping relationship between the detection areas and the microchannel groups; an acoustic emission sensor is set in each detection area to collect the raw acoustic emission voltage signal. Local heat absorber temperature sensors are installed on the surface of the heat absorber in each detection area to collect the local heat absorber temperature. Collect the inlet temperature of the solar collector. collector outlet temperature Total mass flow rate Local microchannel mass flow rate Collector pressure difference Pressure difference between the two ends of the circulating pump Solar irradiance Ambient temperature Obtain the density of the heat transfer fluid. Specific heat capacity of heat transfer fluid Circulating pump efficiency Effective light-receiving area of ​​the solar collector Establish an adjacency matrix for the detection region. ,in Indicates the first The detection area and the first Adjacent detection areas Indicates the first The detection area and the first The detection areas are not adjacent.

[0036] It needs to be explained that the interlayer connection interface is divided along the microchannel arrangement direction into... When detecting a single detection area, based on the effective light-receiving surface size of the solar collector, the number of microchannels, and the localization resolution of the acoustic emission sensor for micro-misalignment events at the interlayer interface, the entire interlayer interface is divided into equal parts. Each segment is arranged sequentially along the arrangement direction, and each segment constitutes a detection area; The specific values ​​are determined by the structural parameters of the microchannel flat plate solar collector. After division, each detection area covers two sets of flow units formed by adjacent microchannels. When establishing a fixed mapping relationship between the detection area and the microchannel group, a unique number is assigned to each detection area. Based on the correspondence between the spatial location of the microchannel and the boundary of the detection area, the first... Each detection area is associated with a microchannel group consisting of two adjacent microchannels and an interlayer connection interface, forming a mapping table between the detection area number and the microchannel group number. This mapping table is stored in the device parameter database for subsequent control calls. When setting an acoustic emission sensor in each detection area, the acoustic emission sensor is attached to the microchannel carrier layer at a position with a stable mechanical propagation path to the interlayer connection interface. The sensor maintains acoustic contact with the measured surface through a coupling medium, and continuously records the first [number] ... The acoustic emission raw voltage signal of each detection area The The unit is volt; when installing a local absorber plate temperature sensor on the surface of the absorber plate, the sensor should be installed in an area close to the interlayer interface and without obstructing solar radiation. It should form thermal contact with the back of the absorber plate through bonding or pressing to measure the temperature of the first... Temperature of the local heat absorber plate corresponding to each detection area The unit is Kelvin; collector inlet temperature and outlet temperature Temperature is obtained by installing temperature sensors on the inlet and outlet pipes of the solar collector; the total mass flow rate ṁ(t) is measured by a mass flow meter installed on the main pipeline of the solar collector; the mass flow rate of the local microchannel group is also measured. Local flow sensors are configured on each microchannel branch to acquire data. When local flow sensors are difficult to install, the flow rate is calculated based on the real-time opening signal of the local regulating valve, the differential pressure across the valve, and the valve flow characteristics. The local mass flow rate of each microchannel group; during calculation, the flow coefficient corresponding to the current opening degree is first obtained from the valve flow characteristic relationship. Based on the flow equation of incompressible fluid through a regulating valve The calculation yielded, where The differential pressure across the local regulating valve, The heat transfer fluid density; the valve flow characteristics are obtained from standard flow characteristic data provided by the valve manufacturer; collector pressure difference. The pressure difference across the circulating pump is measured by differential pressure sensors at the inlet and outlet of the solar collector. Measured by differential pressure sensors at the pump inlet and outlet; solar irradiance. The ambient temperature was collected by a solar irradiance meter installed on the light-collecting surface of the solar collector. Temperature data is collected by temperature sensors positioned around the collector, avoiding direct sunlight; heat transfer fluid density. and specific heat capacity The data is obtained from the original manufacturer's calibration database based on the heat transfer fluid type and current average inlet and outlet temperatures. The relationships in the database are derived from fitting standard physical property measurement data. During fitting, temperature is used as the independent variable, and the least squares method is employed to perform polynomial fitting on density and specific heat capacity respectively. The fitting order is determined based on the fitting residuals and the number of data points. The obtained polynomial coefficients are stored in the physical property database. The standard physical property measurement data originates from the physical property data sheets provided by the heat transfer fluid manufacturer. (Circulation pump efficiency...) The efficiency-flow characteristic curve provided by the pump manufacturer was obtained based on the current volumetric flow rate; the effective light-receiving area of ​​the solar collector. The adjacency matrix of the detection area is determined by reading from the equipment design parameters or by measuring geometric dimensions and calibrating the light transmittance of the light-transmitting cover. The establishment process is as follows: based on the spatial distance between the center points of each detection area and the existence of shared boundaries, when the r-th detection area is adjacent to the r-th detection area... When two detection regions are adjacent and the center distance between them is less than the preset adjacency judgment scale, the matrix elements will be... Assign a value of 1 when the first The detection area and the first When a detection region is not adjacent or the center distance between two regions is greater than or equal to a preset adjacency determination scale, the value is assigned to 0; the matrix is ​​used to limit the subsequent calculation of the spatiotemporal aggregation factor to only consider the cooperative relationship between adjacent regions.

[0037] Define the running state vector ,in , , , ; This is a reference value for solar irradiance. This is a reference value for temperature difference. This is a reference value for total mass flow rate. The collector pressure differential reference value is used; during the operating cycle where independent testing confirms that the interlayer connection interface is in a normal state, the initial valid acoustic emission events are extracted using preset initial acoustic emission event identification rules, and the statistical time window is calculated. Initial effective acoustic emission event rate within Logarithmic transformation of the initial effective acoustic emission event rate is given by the following formula: ,in This is the logarithmic transformation value of the initial effective acoustic emission event rate. To prevent positive values ​​with a logarithm of zero from being corrected, the operating state vector obtained from the normal operating cycle will be used as the correction parameter. Initial effective acoustic emission event rate Logarithmic transformation value of the initial effective acoustic emission event rate Store the acoustic emission background database to form state conditions; obtain the current running state. The first in the state-condition acoustic emission background database The running state vector of a normal sample Normalized distance between ; Calculate nonlinear kernel weights The formula is: ,in The state neighborhood scale parameter, The number of normal samples used in the calculation. Indicates the current running status With the The running state vector of a normal sample The normalized distance between them is obtained using the same distance calculation method; nonlinear kernel weights are used. Calculate the logarithmic baseline of the normal event rate Dispersion with normal state The calculation formula is: and ; Calculate the acoustic emission background reference under state conditions When the calculation result is less than zero, Set it to zero.

[0038] It needs to be explained that the running state vector is defined. At that time, the solar irradiance, the temperature difference between the inlet and outlet of the collector, the total mass flow rate, and the pressure difference of the collector were dimensionlessized using their respective reference values ​​to obtain four components. , , and ;in Used to reflect the degree of deviation of the current solar irradiance from the reference irradiance level. Used to reflect the degree of deviation between the collector inlet temperature and the ambient temperature relative to a reference temperature difference. Used to reflect the degree of deviation of the total mass flow rate from the reference flow rate. Used to reflect the degree of deviation of the collector pressure difference from the reference pressure difference; the solar irradiance reference value The solar irradiance value corresponding to the standard test conditions specified in the collector design documents should be used preferentially. When the solar irradiance value is not specified in the collector design documents, solar irradiance data should be collected during operation when the interlayer connection interface is independently tested and confirmed to be in normal condition, and the statistical median value of the collected data should be used as the standard value. The "normal state" refers to a state where industrial CT scanning confirms the absence of micro-deadlock, cracks, and connectivity damage at the interlayer connection interface, and that the collector's heat output meets the normal range; the temperature difference reference value... The design value corresponding to the difference between the inlet temperature and the ambient temperature under the collector's design conditions should be used first. If the collector's design conditions do not specify this temperature difference, during operation where the interlayer connection interface is independently tested and confirmed to be in a normal state, the inlet temperature should be used as the primary reference. and ambient temperature Calculate the temperature difference, and use the statistical median of the calculated temperature difference as... The total mass flow rate reference value The design total mass flow rate specified under the rated operating conditions of the solar collector should be used preferentially. The rated operating conditions refer to the conditions under which the solar collector operates according to the rated solar irradiance, rated inlet temperature, and rated total mass flow rate specified in the equipment design. When the design documents do not specify the design total mass flow rate, the total mass flow rate data is collected through the main pipeline mass flow meter while the solar collector is operating under rated conditions, and the statistical median value of the collected data is used as the reference value. The reference value of the differential pressure of the solar collector. The design inlet and outlet pressure difference specified under the rated operating conditions of the solar collector should be used first; when the design documents of the solar collector do not specify the design inlet and outlet pressure difference, the pressure difference should be used when the solar collector is designed according to... During operation at the corresponding total mass flow rate, differential pressure data of the solar collector is collected by differential pressure sensors installed at the inlet and outlet of the collector, and the statistical median value of the collected data is used as... The statistical median values ​​are calculated based on data collected continuously for a preset sampling duration, where the preset sampling duration is the continuous sampling time covering one normal operating cycle. The normal operating cycle refers to the operating cycle within which the inter-layer connection interface is confirmed to be in a normal state through independent detection. The final determined... , , and The corresponding equipment number is stored in the equipment parameter database; the typical value and design value are read from the equipment parameter database; independent testing is performed to confirm that the interlayer connection interface is in a normal operating cycle. The independent testing method is to perform non-destructive testing on the interlayer connection interface through industrial CT scanning to confirm that there are no micro-misfits, cracks, or connectivity damage. Combined with heat transfer performance testing, it is confirmed that the heat output of the collector meets the normal range. The operating cycle containing only the normal structural state is selected as the background data acquisition cycle; when extracting the initial valid acoustic emission events using the preset initial acoustic emission event identification rules, the preset initial acoustic emission event identification rules include bandpass filtering of the original acoustic emission voltage signal to remove mechanical vibration and environmental noise, setting an initial amplitude threshold to exclude low amplitude noise, and setting a minimum duration and event dead time to avoid the same elastic wave being counted repeatedly. The initial amplitude threshold is determined according to the statistical distribution of acoustic emission background noise under normal conditions, and the upper quantile of the acoustic emission signal amplitude under normal conditions is taken as the initial threshold; statistical time window. Initial effective acoustic emission event rate within At that time, the time window The number of initial valid acoustic emission events identified internally divided by The initial effective acoustic emission event rate of the detection area within the corresponding time window is obtained; The value of is determined based on the timescale of the micro-misfit events at the interlayer connection interface and the real-time requirements of online monitoring, and is obtained through statistical analysis of historical acoustic emission event intervals; when performing a logarithmic transformation on the initial effective acoustic emission event rate, the formula is used. Transform the event rate to the logarithmic domain, where To prevent positive correction parameters with a logarithm of zero, the method of determination is to statistically calculate the minimum non-zero value of the initial effective acoustic emission event rate under normal conditions, and then take a positive number less than the minimum non-zero value as the correction parameter. This ensures that logarithmic calculations are always defined; the operating state vector obtained from the normal operating cycle... Initial effective acoustic emission event rate Logarithmic transformation value of the initial effective acoustic emission event rate When storing the state-conditional acoustic emission background database, the operating state vector, event rate, and logarithmic transformation value corresponding to each normal sample are stored according to the detection area number and timestamp, and the sample validity identifier is marked to form a database that can be used for subsequent state neighborhood queries; the current operating state is obtained. The first in the state-condition acoustic emission background database The running state vector of a normal sample Normalized distance between When using the weighted Euclidean distance formula Calculation, where This indicates that the square root operation is performed on the result of the weighted sum of squared differences within the parentheses. The current running state vector is the first... One portion, For the first The value of the component corresponding to each normal sample. The weighting coefficients for each component are determined using the analytic hierarchy process (AHP) and reflect the relative importance of the four operational parameters—solar irradiance, temperature difference, flow rate, and pressure difference—on the acoustic emission event rate. The nonlinear kernel weights are then calculated. When using the formula ,in The state neighborhood scale parameter is determined by taking the standard deviation of the distances between all pairs of running state vectors of normal samples in the state condition acoustic emission background database. The number of normal samples participating in the calculation is set to a value no less than a first preset proportion of the total number of normal samples in the state-conditional acoustic emission background database. When the number of normal samples is insufficient, all normal samples are used. The first preset proportion is determined by dividing all normal samples according to time order after establishing the state-conditional acoustic emission background database, and using cross-validation, selecting a different proportion of nearest-neighbor normal samples as the number of normal samples participating in the calculation each time. The optimization objective is to minimize the prediction error of the logarithmic baseline of the normal event rate under the current operating state. The proportion of the sample size corresponding to the minimum prediction error is determined as the first preset proportion. The prediction error is calculated by comparing the root mean square error between the logarithmic baseline of the normal event rate obtained by weighting the normal samples involved in the calculation and the actual logarithmic event rate of the normal samples not involved in the calculation. When the number of normal samples is insufficient, all normal samples are taken. Nonlinear kernel weights are used. Calculate the logarithmic baseline of the normal event rate hour, This means that the logarithmic event rates of each normal sample are weighted and averaged based on the similarity between the current running state and each normal sample, to obtain the i-th sample under the current running state. Logarithmic baseline of normal acoustic emission event rate for each detection area; calculation of dispersion in normal state. hour, This represents the weighted variance of the logarithmic event rate of each normal sample relative to the baseline, reflecting the fluctuation range of the acoustic emission event rate under normal conditions; it is used to calculate the acoustic emission background baseline under state conditions. When using the formula The logarithm of the normal event rate is restored to the event rate scale; when the calculated result is less than zero, [the following is omitted]. Set it to zero.

[0039] Based on the logarithm of the normal event rate Dispersion with normal state Build dynamic event trigger thresholds The formula is: ,in Background deviation control coefficient; for the original acoustic emission voltage signal After bandpass filtering, removal of fixed-frequency mechanical vibration components, and amplitude normalization, the amplitude of the original acoustic emission voltage signal exceeds the dynamic event triggering threshold. When the minimum duration, maximum duration, and event dead time requirements are met, the signal segment is defined as a valid acoustic emission event; the current time window is statistically analyzed. Inner The set of valid acoustic emission events in a detection area and current effective event rate ; Calculate the standardized outliers of the state The formula is: ,in It is a dimensionless stable term; calculate the event-time synergy between adjacent detection regions. and normalized synergy The formula is and ;in For event time coordination window, It is a dimensionless stable term; obtain the first term. The detection area and the first Spatial distance between the centers of each detection area Spatial weights are constructed using the adjacency matrix and spatial distance between detection regions. The formula is: ,in For spatial correlation scale; calculate spatiotemporal clustering factor The formula is: ,in For the first The set of adjacent detection regions of a detection region.

[0040] It needs to be explained that the dynamic event triggering threshold is constructed. At that time, the public middle The current running state of the first Logarithmic baseline of normal event rate in each detection area This serves as a measure of the fluctuation of the logarithm of the normal event rate. Background deviation control coefficient; The determination method is to take the logarithmic event rate of all normal samples in the state-conditional acoustic emission background database. relative to their respective state weighted benchmarks The standardized deviation is calculated, and the upper quantile of the standardized deviation is determined to ensure that the probability of a normal sample being misclassified as a valid event does not exceed a preset false alarm rate. This upper quantile is then used as the standardization deviation. The value of ; the preset false alarm rate is determined by plotting different values ​​based on the standardized deviation data of historical normal samples and known abnormal samples. The relationship curve between the false alarm rate of normal samples being misclassified as valid events and the false negative rate of abnormal samples being missed is analyzed. The false alarm rate that minimizes the sum of the false alarm rate and the false negative rate is selected as the preset false alarm rate. Then, the upper quantile of the normal sample standardized deviation distribution corresponding to the preset false alarm rate is taken as the preset false alarm rate. The value of ; for the original acoustic emission voltage signal When performing bandpass filtering, the lower and upper frequency limits are determined based on the elastic wave frequency band generated by the slight misalignment at the interlayer interface. A standard acoustic emission source is used to excite the microchannel flat plate solar collector under monitoring, and the spectral range of the effective acoustic emission signal is measured. The frequency band with concentrated energy is selected as the bandpass filtering range. To remove fixed-frequency mechanical vibration components, vibration signals from rotating machinery such as circulating pumps and fans are collected. The fundamental frequency and harmonic frequencies of the mechanical vibration are extracted using Fourier analysis, and a notch filter is used to suppress the corresponding frequency components in the original acoustic emission voltage signal. Amplitude normalization is performed using peak normalization. The original acoustic emission voltage signal after filtering and vibration removal is divided by the absolute value of the peak value within a preset time window, ensuring the processed signal amplitude is within a set range. The processed original acoustic emission voltage signal amplitude must exceed the dynamic event trigger threshold. When the minimum duration, maximum duration, and event dead time requirements are met, the signal segment is defined as a valid acoustic emission event. The minimum duration is determined by measuring the duration distribution of valid acoustic emission events generated by micro-misfit propagation at the interlayer interface through calibration tests, and taking the lower quantile of the distribution as the minimum duration. The maximum duration is taken as the upper quantile of the distribution. The event dead time is determined based on the attenuation time of the acoustic emission signal at the interlayer interface and the sensor's residual vibration time. The time required for the sensor response caused by the same acoustic emission event to decay to the background noise level is taken as the event dead time. The current time window is statistically analyzed. Inner The set of valid acoustic emission events in a detection area At that time, the time window The arrival times of all valid acoustic emission events identified within are arranged sequentially to form a sequence. ,in The number of valid acoustic emission events within the time window; the current valid event rate. pass Calculated; Standardized outlier of the calculated state At that time, the public was adopted ,That To prevent positive correction parameters with a logarithm of zero, the parameters used during the construction of the state-conditional acoustic emission background database are... same; For the dimensionless stable term, the variance of the normal sample log event rate of all detection regions in the state-conditional acoustic emission background database under all normal time windows is taken. The smallest non-zero value is calculated, and the square root of the smallest non-zero value is taken as... ,when When the value is zero, the denominator is guaranteed to be non-zero; in the formula, the numerator represents the deviation of the current effective event rate logarithm from the normal baseline, and the denominator represents the stabilization estimate of the normal fluctuation level. The ratio is used to transform the anomaly level under different detection areas and different operating conditions to a unified dimensionless scale; the event time coordination between adjacent detection areas is calculated. When, formula middle Indicates the first The first detection area The arrival time of a valid acoustic emission event. Indicates the first The first detection area The arrival time of a valid acoustic emission event. For event time coordination window; The determination method is as follows: based on the propagation time of acoustic emission signals between adjacent detection areas and the statistical characteristics of the synchronicity of events in adjacent areas caused by micro-misfit propagation at the interlayer connection interface, acoustic emission events are artificially generated at the boundary of adjacent areas during calibration experiments, and the time difference recorded by the sensors in the two areas is measured. The width parameter of the time difference distribution is taken as the standard. ; Calculate normalized cooperativity When using the formula ,in This is a dimensionless stable term, determined by taking the minimum non-zero value of the number of effective acoustic emission events in adjacent detection areas under normal conditions. The benchmark is used to prevent the denominator from being zero when the number of events is zero, ensuring that the normalized coherence quantity can stably reflect the degree of temporal correlation even when there are large differences in the number of events; to obtain the first The detection area and the first Spatial distance between the centers of each detection area At that time, based on the center coordinates of each detection area determined during the division of the detection area, the straight-line distance between the two center points is calculated using the Euclidean distance formula. The coordinates are obtained from the solar collector structural drawings. Spatial weights are constructed using the adjacency matrix between detection areas and the spatial distance. When, formula middle To detect the elements of the region adjacency matrix, when the... The detection area and the first When two detection areas are adjacent When the first The detection area and the first When the detection areas are not adjacent ; The spatial correlation scale is determined by taking the statistical average of the center distances of all adjacent detection areas; the spatiotemporal aggregation factor is calculated. When, formula middle For the first The set of adjacent detection regions of the nth detection region, where the exponent term represents the set of all adjacent regions to the nth detection region. The sum of weighted coordination values ​​of each detection region is mapped to a range of 0 to 1 through an exponential transformation. This results in a higher degree of temporal coordination or closer spatial distance between adjacent regions. The closer it is to 1, the better. The more obvious the spatiotemporal clustered structural changes around each detection area, the better.

[0041] Standardize the state outliers Convert to non-negative smoothed risk The formula is: ,in Dimensionless shape coefficients; construct spatiotemporal co-enhancing terms The formula is: ,in For the nonlinear coefficients of the spatiotemporal coordination enhancement term, The exponent for spatiotemporal coordination enhancement; constructing nonlinear interaction terms. The formula is: ,in For nonlinear interaction term coupling coefficients, The exponent of the nonlinear interaction term is obtained; Nonlinear acoustic emission state index of each detection area The formula is: .

[0042] It needs to be explained that the state is standardized to include outliers. Convert to non-negative smoothed risk When, formula middle It is a dimensionless shape coefficient used to control the transition rate of the function from the linear segment to the saturation segment; The determination method is to collect data from the microchannel flat plate solar collector under known normal conditions, pre-critical conditions, and continuous misalignment critical conditions. Sample, with Sample corresponding For subsequent nonlinear acoustic emission state indices The optimization objective is to achieve the highest accuracy in hierarchical identification. This is determined through cross-validation within a preset search range. The value is determined by statistically analyzing all known samples. Value, take The maximum value is denoted as Set the lower limit of the preset search range to The upper limit is set to ,make When varying within the range exist The typical value range of can cover a variety of shapes from approximately linear to approximately saturated; in the formula For soft addition functions, when When it is a large positive value Approximately equal to ,when When it is a large negative value Approaching zero, the state-standardized outliers are transformed into non-negative and smooth risk measures; a spatiotemporal co-enhancing term is constructed. When, formula middle For the nonlinear coefficients of the spatiotemporal coordination enhancement term, For the spatiotemporal coordination enhancement term index; and The determination method is to calculate the corresponding spatiotemporal aggregation factor using two types of data: synchronous acoustic emission events and asynchronous acoustic emission events in adjacent detection areas. Two types of data Enhanced nonlinear acoustic emission state index The optimization objective is to maximize the distinguishability of synchronous events, which is determined through nonlinear fitting. and ; in the formula The nonlinear amplification term representing the spatiotemporal aggregation factor, when When it is zero An equal value of 1 indicates no additional enhancement when spatiotemporal coordination is absent. When it increases, A value greater than 1 causes the enhancement term to grow slowly at first and then rapidly, highlighting the influence of highly clustered states; a nonlinear interaction term is constructed. When, formula middle For nonlinear interaction term coupling coefficients, For non-linear interaction terms, the exponent is used. and The determination method is to calculate based on samples with known micro-misfit area ratios and connectivity in calibration tests. and ,by The optimization objective is to minimize the prediction error of the actual disconnection trend, which is determined through multivariate regression. and ; in the formula This represents the multiplicative coupling term between the degree of spatiotemporal clustering and the local risk quantity, when zero or When it is zero, When the value is equal to 1, no additional enhancement is produced. When both increase simultaneously, the exponential function makes... Rapid increase reflects the synergistic amplification effect when the degree of anomaly and spatial aggregation occur together; the first... Nonlinear acoustic emission state index of each detection area When, formula Multiply the nonnegative smoothing risk, the spatiotemporal collaborative enhancement term, and the nonlinear interaction term, where Provides a basic metric for the degree of anomaly in a single detection area. Provides an enhancement factor for the spatiotemporal clustering of adjacent regions. It provides an additional amplification factor for the coupling of anomalies and clusters; the product of the three factors makes it possible to achieve a situation where there are only local anomalies but no spatial clusters. Maintaining a moderate level, only when spatially concentrated but with low local risk. Similarly suppressed, when local anomalies occur simultaneously with synchronous activities in adjacent areas. This allows for a more sensitive characterization of the evolutionary trend of interlayer interface from dispersed micro-misalignment to connected misalignment.

[0043] A calibration microchannel flat-plate solar collector with the same material composition, microchannel structure, interlayer bonding process, and sensor arrangement as the microchannel flat-plate solar collector to be monitored was prepared. Thermal cycling conditions were applied to the calibration microchannel flat-plate solar collector while data was collected synchronously. The nonlinear acoustic emission state index of the calibration microchannel flat-plate solar collector was calculated. During the preset thermal cycling phase, the thermal cycling operation is stopped, and the area of ​​micro-misfit is obtained using industrial CT. Total area of ​​interlayer connection interfaces and the area of ​​the largest continuous misfit region ; Calculate the proportion of micro-misfit area and micro-disconnection connectivity The formula is: and , The parameter is a positive correction parameter; based on the preset area critical value. and connectivity threshold Determine the calibration stage for the critical state of continuous mis-adhesion, when the proportion of micro-mis-adhesion area... Greater than or equal to the preset area threshold value And slight disconnection connectivity Greater than or equal to the critical value of connectivity At that time, the corresponding thermal cycle stage is determined as the continuous misalignment critical state calibration stage; the calibration corresponding to the continuous misalignment critical state calibration stage is performed using the nonlinear acoustic emission state index of the microchannel flat plate collector. Recorded as a critical index for continuous loss of interest Establish normalized critical process variables The formula is: ,in To establish a benchmark for the nonlinear acoustic emission performance of microchannel flat-plate solar collectors for calibration. This is a dimensionless stable term; based on the normalized critical process variable of the microchannel flat plate solar collector before the calibration stage of continuous misalignment critical state. The statistical distribution selects the pre-critical proportion Obtaining pre-critical indicators The calculation formula is: Statistical calibration of microchannel flat plate solar collectors during the pre-critical state The statistical distribution of the rate of change yields the maximum permissible state growth rate. ;Will The rate of change continuously exceeds the maximum permissible rate of increase. Furthermore, a state exhibiting an accelerating growth trend is defined as a rapid development state. This rapid development state... The statistical threshold of the rate of change as a threshold for rapid development ,Will , , , Store it.

[0044] It should be explained that when preparing the calibration microchannel flat plate solar collector, the material combination, microchannel structure, interlayer bonding process, and sensor arrangement are kept consistent with those of the solar collector to be monitored. After preparation, a thermal cycle condition corresponding to the actual operating conditions of the device to be monitored is applied to the calibration solar collector. The irradiance variation range, inlet temperature fluctuation amplitude, and flow rate adjustment range of the thermal cycle condition are extracted from the historical operating data of the device to be monitored. During the application process, the original acoustic emission voltage signal, operating status parameters, and local temperature data are collected simultaneously to calculate the nonlinear acoustic emission state index of the calibration solar collector. The thermal cycling process is stopped and industrial CT scanning is performed during a preset thermal cycling phase. This preset thermal cycling phase is divided according to an equal number of thermal cycling cycles, with the specific interval determined based on the expected degradation rate of the interlayer interface and the cost of industrial CT inspection. Before scanning, the calibration collector is cooled to room temperature. The CT scan resolution meets the requirements for identifying micron-level misalignment defects. The scanned image is then subjected to grayscale thresholding, binarization, and connected component analysis to extract the first... Micro-dead area within each detection zone Total area of ​​interlayer connection interfaces and the area of ​​the largest continuous misfit region When calculating the proportion of micro-misfit area, the following method is used: ,in This is the sum of the areas of all micro-misfit regions within the stated region. The geometric total area of ​​the interlayer connection interface in the region is used; when calculating the degree of micro-defit connectivity, the following is adopted: ,in This represents the area of ​​the largest single, continuous area of ​​mislabeling. As a positive correction parameter, a second preset ratio is taken as the total area of ​​the interlayer connection interface in the detection region. The second preset ratio is based on the minimum identifiable misalignment area of ​​industrial CT and The magnitude is determined; a preset area critical value is set. and connectivity threshold The determination method is as follows: A mapping relationship is established between the micro-misfit area ratio, connectivity degree, and the decrease in the effective heat transfer capacity of the collector through heat transfer performance testing and structural strength analysis. The micro-misfit area ratio and connectivity degree corresponding to the point where the effective heat transfer capacity decreases to a preset allowable limit are selected as critical values. The preset allowable limit is determined based on the collector's design thermal performance indicators and safety margin. and At that time, the corresponding thermal cycling stage is determined as the continuous mis-adhesion critical state calibration stage, and the data recorded during the stage are... Statistical mean as a critical indicator of continuous loss of interest Establish normalized critical process variables When, in the formula To calibrate the solar collector in the normal state during the initial stage of the thermal cycle The statistical average, This is a dimensionless stable term, taking the value of The third preset ratio is used to prevent the denominator from being too small; the third preset ratio is taken in the normal state stage. Time series standard deviation and The ratio, i.e. The variable will Linear mapping to 0, A scale of 1 is used to unify the state process of different detection areas; based on the continuous loss of adhesion critical stage Statistical distribution selects the pre-critical proportion At that time, all data from multiple calibration collectors before the critical stage of continuous misalignment is collected. The optimal sample is determined through receiver operating characteristic curve analysis, with preset false positive and false negative rates as constraints. A threshold is set to ensure that the pre-critical warning time meets the early identification requirements; thus, pre-critical indicators are obtained. ; Statistical pre-critical state period When calculating the rate of change, the difference between adjacent sampling times is used to calculate the rate of change sequence, and the upper quantile of the rate of change sequence is taken as the maximum permissible state growth rate. The upper quantile is selected based on a preset safety margin; the preset safety margin is taken as the normal state stage. In the cumulative distribution of the rate of change sequence, the cumulative probability equals the rate of change value corresponding to the preset upper limit of the false alarm rate, and the rate of change value is directly used as... ; keep the rate of change above Furthermore, a state exhibiting accelerated growth is identified as a rapid development state. Accelerated growth is determined by the sign of the second difference in the rate of change sequence. When the rate of change itself is positive and the second difference is positive multiple times consecutively, it is considered accelerated growth. The statistical threshold of the rate of change sequence during the rapid development state is used as... Finally , , , Stored in the critical calibration database of interlayer connection interfaces.

[0045] Get the first in real time Nonlinear acoustic emission state index of each detection area ; Calculate short-period changes and long-term changes The calculation formula is: and ;in For the current time, To calculate a longer time window for short-cycle calculations, For long-period calculations, the time window is long. ; Calculate trend consistency The formula is: ,in A dimensionless stable term; construct a nonlinear evolution factor. The formula is: ,in It is a dimensionless state scale parameter. The coefficient is a dimensionless coupling coefficient; when and and At that time, the judgment of the first Each detection area enters a pre-critical state; when Time to determine the first Each detection area enters a critical state of continuous loss of adhesion; when Maintain normal monitoring status; when but It was determined to be in a high-level stable state.

[0046] It needs to be explained that the real-time acquisition of the first... Nonlinear acoustic emission state index of each detection area At that time, the current time is read according to the preset calculation cycle. The value, the preset calculation period and the acoustic emission event statistical time window Maintain consistency to ensure that the update frequency of status indicators is synchronized with the rhythm of acoustic emission signal processing; calculate short-period changes. and long-term changes At that time, store the time before the current time respectively. Duration and Duration corresponding Historical values ​​are obtained by subtracting the corresponding historical value from the current value to obtain the change over two time scales. To ensure a long calculation time window for short-cycle calculations, the method is to take one-third of the development time from the start of the pre-critical state to the continuous loss of contact critical state in the calibration test, plus the statistical time window of acoustic emission events. The larger of the two; To ensure a long calculation time window, take... Integer multiples thereof, the multiples are determined according to the calibration test. The typical number of cycles required for a transition from slow to rapid growth in the pre-critical state is determined, satisfying the following conditions. and Not exceeding one-fifth of the duration of the normal state phase in the calibration test; reflect The latest direction and magnitude of change on a short timescale. reflect The cumulative change trend over a longer time scale is used in conjunction to distinguish between instantaneous fluctuations and continuous development; the consistency of the trend is calculated. When, formula The numerator is the product of the short-period change and the long-period change; the product is positive when the two have the same sign and negative when they have opposite signs. The denominator is the absolute value of the product plus... This compresses the result to between -1 and 1; This is a dimensionless stable term, taking the value of and The fourth preset proportion of the standard deviation of the product sequence under normal conditions, which is determined through statistical analysis of normal state samples, ensures that the absolute value of the product is much greater than... hour When the product is close to ±1, it is close to zero. Approaching zero without division-to-zero anomaly; constructing a nonlinear evolution factor When, in the formula The short-period variation is normalized to the range of -1 to 1 using the hyperbolic tangent function. This is a dimensionless state scale parameter, taking values ​​under normal conditions. The standard deviation of a short-period change series makes the normal fluctuations corresponding to... In The approximate linear region of the function; the second term This is the product of trend consistency and the square of the short-period change. The dimensionless coupling coefficient is determined by combining known pre-critical state samples and normal state samples in a calibration test. , Substitution Expression, using pre-critical state samples Compared with normal state samples The optimization objective is to maximize the inter-class distance, which is determined through a one-dimensional search. The value; when the short-cycle change is positive and the directions of the short and long cycles are consistent, the second term is positive and amplifies the first term, indicating that the trend continues to rise and is strengthened; when the short-cycle change is negative... The squared term is negative, so the second term remains positive, but its direction is dominated by the first term. Overall, The status remains negative; when determining the status, the procedure should be performed in the following order: first check the critical situation of continuous loss of contact, then check the situation before the critical situation, and finally distinguish between normal and high-level stable conditions. When the state of continuous loss of adhesion is determined; when and and When determining whether to enter the pre-critical state, where From the calibration database, Ensure the long-term trend is upward, and avoid misjudgments caused by short-term surges; when Maintain normal monitoring status; when but If the condition is determined to be in a high-level stable state, it means that the indicator is in the warning range but there are no signs of accelerated development. Continue monitoring and do not initiate local flow regulation.

[0047] Obtain the basic mass flow rate of the microchannel group corresponding to the detection region before entering the critical state. Define the criticality variable. The formula is: ; Calculate the temperature change state of the local heat absorber plate The formula is: ,in For the first The surface temperature of the heat absorber plate at the corresponding location of each detection area. Establish a calculation window for temperature changes; construct dimensionless thermal state variables. The formula is: ,in This is a normal temperature change scale. It is a dimensionless stable term; calculate the pressure safety margin. The calculation formula is: ,in The maximum allowable pressure difference for the solar collector. It is a dimensionless stable term; calculate the local flow increment. The formula is: ,in To maximize traffic increment, This is the criticality weighting coefficient. This is the thermal state weighting coefficient. For the critical degree of nonlinearity, The thermal nonlinearity index is used to calculate the target local mass flow rate. ,in For the target local mass flow rate, and These represent the minimum and maximum allowable mass flow rates for the local microchannel group, respectively; based on the temperature change state of the local absorber plate and Make feedback and adjustments when and When economic activity resumes, when and At this time, it is permissible to continue increasing the local flow rate under pressure safety constraints, when Stop modifying local flow at a certain time; The upper limit of normal temperature variation is the economic operating flow rate, which is the recommended flow rate with the lowest energy consumption. As a safe threshold for the rate of temperature decrease, the Economic operating flow and Retrieved from the device parameter database; when Stop increasing the local flow when the time comes; When an anomaly occurs, it should be handled accordingly.

[0048] It should be explained that the basic mass flow rate of the microchannel group corresponding to the detection region before entering the critical state is obtained. At that time, the average local mass flow rate during the most recent stable operating period of the microchannel group is retrieved from the device parameter database. When a critical state is detected, the current actual flow rate is frozen as a benchmark; a criticality degree variable is defined. hour, , and Taken from the calibration database, the numerator represents the extent to which the current indicator exceeds the pre-critical threshold, and the denominator is the width of the interval from the pre-critical threshold to the continuous misfit threshold. the sum of To prevent the denominator from being too small, The value is between 0 and 1; calculate the local temperature change state of the absorber plate. hour, The data was obtained from the equipment parameter database through autocorrelation analysis of the local absorber plate temperature time series under normal operating conditions. The data was derived from the time delay corresponding to the first drop of the correlation coefficient below the statistical noise threshold. The statistical noise threshold was determined by extracting a data segment from the end of the autocorrelation coefficient of the local absorber plate temperature time series under normal operating conditions that has no obvious periodic component, calculating the standard deviation of the autocorrelation coefficient of this data segment, and taking a set multiple of the standard deviation as the statistical noise threshold. This set multiple is determined by comparing different threshold values. The ability to distinguish between normal temperature fluctuations and abnormal temperature drifts is determined, and the optimal threshold is stored in the equipment parameter database. express Average rate of temperature change of the absorber plate over a period of time; construct dimensionless thermal state variables. hour, Take the normal state The upper quantile of the absolute value sequence is determined based on the allowable temperature fluctuation range; Pick The product of the product and the preset stability coefficient, the preset stability coefficient after normal data disturbance. Sensitivity analysis was conducted to obtain the pressure safety margin; hour, Provided in the solar collector design specification; Pick The product of the pressure stability factor and the preset pressure stability factor, which is based on the standard deviation of the differential pressure sensor noise and The ratio is determined; the local flow increment is calculated. hour, The difference between the maximum allowable flow rate and the base flow rate of the microchannel group; and The entropy weight method is used to determine the expected flow increment samples under different criticality and thermal state combinations from the calibration data. The entropy weight method assigns weights based on the degree of variation of the index. and By using different and The target flow increment under the combined conditions is determined by regression fitting of the response variable; When the pressure safety margin is negative, the flow rate increment is zero; when calculating the target local mass flow rate, The function limits the sum of the base flow and the increment to 1. and between, and Taken from the equipment parameter database; during feedback adjustments, The method for determining this is to collect a sequence of absolute values ​​of local absorber plate temperature changes under normal conditions. For multiple samples, plot their empirical cumulative distribution function, and then... Determined to make normal samples Exceed When the ratio equals the preset false alarm rate The preset false alarm rate is determined by analyzing the overlapping areas of historical normal and abnormal temperature change samples. The false alarm rate that minimizes the sum of the false alarm rate for normal samples and the false negative rate for abnormal samples is selected. The false alarm rate and its corresponding value are then used to determine the optimal false alarm rate. The value is written into the equipment parameter database; the economic operating flow rate is calculated with the goal of minimizing the sum of pump energy consumption and net heating energy. Pick The product of this and a preset descent amplification factor, which is determined based on the requirements for preventing overcooling shock; when Immediately stop increasing the local flow; when When an anomaly occurs, the system initiates an emergency response procedure, which includes maintaining safe traffic flow, issuing maintenance alerts, and logging event data.

[0049] Calculate effective heat power The formula is: ; Calculate the heat collection efficiency The formula is: Heat collection efficiency exist Calculated within the evaluation range, Calculate the minimum effective irradiance threshold; calculate the input power of the circulating pump. The formula is: , Calculate the net effective heating power. The formula is: Construct the running state vectors before and after adjustment and calculate the running state distance, selecting only those with a running state distance less than or equal to... The evaluation is conducted within a specific time window. Set a threshold for allowed running states; define a matching window. The distance between the operating states before and after adjustment is less than or equal to A continuous time window; in the matching window Internal calculation of effective thermal energy Pump energy consumption The formula is and Calculate net heating energy The formula is: Define the net heating efficiency coefficient. The formula is: , A positive energy stabilization term; define the acoustic emission state improvement coefficient. The formula is: ,in To adjust the mean value of the acoustic emission state index, To adjust the mean values ​​of the front acoustic emission state parameters; a local temperature change improvement coefficient is defined. The formula is: ,in To adjust the average temperature change of the local heat absorber plate after adjustment, To adjust the average temperature change of the local heat absorber plate; when simultaneously satisfying , or The continued growth trend has been suppressed. If the preset net heating maintenance ratio is achieved and the local flow limit and pressure safety limit are not exceeded during the control period, the corresponding operating cycle of this adjustment will be marked as an effective control cycle; only data that meets the normal state requirements within a continuous time window will be marked as normal background candidate data, using exponential decay weighting. Update the state condition acoustic emission background database. The calculation formula is: , The time interval between the sample and the current time. Update the time scale for the background.

[0050] It needs to be explained that the calculation of effective heat power At that time, total mass flow rate The specific heat capacity of the heat transfer fluid is measured in real time by a mass flow meter installed on the main pipeline of the solar collector. Based on the current average inlet and outlet temperatures, the collector outlet temperature was determined from the physical property database. With inlet temperature Temperature data are collected by temperature sensors installed on the inlet and outlet pipes, respectively. The product represents the effective heat absorbed by the heat transfer fluid from the collector per unit time, in watts. When the relative rate of change of the specific heat capacity of the heat transfer fluid with temperature exceeds a preset specific heat capacity change threshold, the calculation is performed using the inlet and outlet enthalpy difference. The enthalpy value is provided by the physical property database; the preset specific heat capacity change threshold is determined by statistically analyzing the specific heat capacity data of the heat transfer fluid within the operating temperature range of the collector, calculating the relative change in specific heat capacity between adjacent temperature points, and taking the maximum relative change that ensures the effective heat power calculation error does not exceed the preset heat power error upper limit as the threshold. The preset heat power error upper limit is determined by the accuracy requirements of the heating efficiency evaluation; the heat collection efficiency is calculated. At that time, solar irradiance The effective light-receiving area of ​​the solar collector is measured in real time by an irradiance meter installed on the light-receiving surface of the collector. Read from the equipment design parameters; the heat collection efficiency is only... Calculated within the evaluation range, The minimum effective irradiance threshold is determined by statistically analyzing the relationship between the measurement uncertainty of solar irradiance and collector efficiency during historical operation. The minimum irradiance value corresponding to the measurement of collector efficiency without exceeding a preset error upper limit is selected. The preset error upper limit is set according to the reliability requirements of the evaluation results. The data is written into the device parameter database; the reliability requirement is the degree of influence of the heat collection efficiency evaluation error on the effective control cycle determination conclusion, and the misjudgment rate of the effective control cycle caused by the heat collection efficiency measurement error is used as the reliability index, through statistical analysis of different... The confidence interval width of the net heating energy difference before and after the adjustment is selected, and the maximum measurement error corresponding to the condition that the confidence interval width is less than the minimum resolvable value of the net heating energy difference is selected as the preset error upper limit; the input power of the circulating pump is calculated. At that time, the pressure difference across the circulating pump Volumetric flow rate is measured by differential pressure sensors at the pump inlet and outlet. Total mass flow rate Divide by the density of the heat transfer fluid get, Querying the physical property database, the efficiency of the circulating pump... The efficiency-flow characteristic curve provided by the pump manufacturer is obtained based on the current volumetric flow rate; calculate the net effective heating power. At that time, it is obtained by subtracting the pump input power from the effective thermal power, representing the net power available for heat utilization after deducting the energy consumption of transmission; when constructing the operating state vector before and after adjustment and calculating the operating state distance, the operating state vector is taken as Each component is normalized according to the same reference value as the acoustic emission background database under state conditions. The operating state distance is calculated using weighted Euclidean distance, and the weight coefficients are determined using the analytic hierarchy process (AHP). A judgment matrix is ​​constructed to assess the influence of five operating state variables—solar irradiance, ambient temperature, inlet temperature, total mass flow rate, and collector pressure difference—on energy evaluation. Each element in the judgment matrix represents a scale of relative importance between two state variables, and the scale value is derived from the correlation coefficient ranking results of the independent variables and net heating energy changes in historical energy data before and after adjustments. The judgment matrix is ​​subjected to a consistency check. When the consistency ratio exceeds the preset consistency upper limit, the element with the largest deviation in the judgment matrix is ​​adjusted and re-checked until the consistency ratio meets the requirements. The preset consistency upper limit is determined by statistically analyzing the distribution of consistency ratio values ​​during the construction of historical judgment matrices, and taking the maximum consistency ratio value corresponding to the weight ranking obtained by the AHP without significant changes as the upper limit. The weight coefficients of each operating state variable are obtained through the normalized eigenvector corresponding to the largest eigenvalue of the judgment matrix. Only operating state distances less than or equal to... The evaluation is conducted within a specific time window. The acceptable operating state matching threshold is determined by statistically analyzing the distribution of operating state distances under the same operating conditions in historical operations, and taking the maximum distance corresponding to the condition that ensures the energy index calculation error within the matching window before and after adjustment does not exceed the preset matching error upper limit as the acceptable operating state matching threshold. The upper limit of the preset matching error is determined by the accuracy requirements of energy evaluation; the matching window is defined. The distance between the operating states before and after adjustment is less than or equal to A continuous time window, in Internally respectively to and Effective thermal energy is obtained by time integration. and pump energy consumption Define the net heating efficiency coefficient. hour, To adjust the net heating energy within the matching window, To adjust the net heating energy within the pre-matching window, For the positive energy stability term, the value is taken as the standard deviation of the absolute value sequence of net heating energy before adjustment to prevent the denominator from being too small; A value greater than zero indicates an increase in net heating energy after adjustment; the acoustic emission state improvement coefficient is defined. hour, and These are the time average values ​​of the nonlinear acoustic emission state parameters within the matching window before and after adjustment, respectively. The values ​​of the dimensionless stability terms in the critical calibration database are used as is. A value less than or equal to zero indicates that the acoustic emission performance indicators have not deteriorated; a local temperature change improvement coefficient is defined. hour, and These are the time averages of the absolute values ​​of the local absorber plate temperature changes within the matching window before and after adjustment, respectively. The values ​​of the positive dimension stable terms in the equipment parameter database are adopted; A value less than zero indicates a decrease in the magnitude of local temperature change; this must be met when determining the effective control period. ; or The sustained growth trend was suppressed. The way to determine that the sustained growth trend was suppressed is to compare the matching window before and after adjustment. The slope of the linear fit is considered suppressed if the adjusted slope is less than the original slope. Alternatively, a preset net heating maintenance ratio can be achieved. This preset ratio is determined by minimizing the sum of the increase in pump energy consumption and the net heating energy loss after adjustment. Historical operating data is used to analyze the net economic benefits of different maintenance ratio values ​​over effective control periods. The net economic benefit is calculated by subtracting the increased pump energy cost due to flow regulation from the net heating energy gain after adjustment. The pump energy cost is determined by electricity prices and pump energy consumption. The maintenance ratio that maximizes net economic benefits while meeting minimum heating guarantee requirements is selected as the preset net heating maintenance ratio. The minimum heating guarantee requirement is determined based on the system's designed heating capacity and user-side heating demand, meaning that the net heating energy after adjustment is not lower than the preset net heating maintenance ratio before adjustment, and the local flow rate does not exceed the upper limit during the control period. and pressure safety limit Only data that meets the normal state requirements within a continuous time window are marked as normal background candidate data. Normal state requirements include... , , Furthermore, it is not under mandatory control; it employs exponentially decaying weights. When updating the state condition acoustic emission background database, The time interval between the sample and the current time. The background update time scale is determined by statistically analyzing the time required for a significant change in the operating characteristics of the equipment, and then taking a fifth preset proportion of that time length as the background time scale. The fifth preset ratio is determined based on the background database's requirements for the adaptation speed of equipment aging; the weights are normalized after being multiplied by the weights of the original state's neighborhood to achieve the fusion of new and old samples.

[0051] Example 2: Based on Example 1, a solar heating efficiency enhancement system for a microchannel flat plate collector, such as... Figure 2 As shown, it also includes:

[0052] The synchronous acquisition and topology construction module is used to establish a synchronous acquisition system for microchannel local connection areas, operating status parameters, acoustic emission signals, local temperature and fluid operation parameters, and to establish a device parameter database and topological relationships of the detection area;

[0053] The acoustic emission background and index module is used to establish a state-condition acoustic emission background database based on the operating state vector under normal conditions, extract effective acoustic emission events and construct spatiotemporal clustering features, and construct nonlinear acoustic emission state indices.

[0054] The pre-critical state identification module is used to establish a calibration relationship between the nonlinear acoustic emission state index and the critical state of the interlayer connection interface using the interlayer connection interface, and to identify the pre-critical state of the interlayer connection interface online.

[0055] The local flow closed-loop control module is used to implement constrained local heat transfer fluid flow regulation for the microchannel group mapped to the detection area corresponding to the pre-critical state, and to perform closed-loop control.

[0056] The heating efficiency evaluation and update module is used to evaluate changes in effective heating energy, heat collection efficiency, pump energy consumption, net heating energy, and acoustic emission status indicators before and after adjustment under operating conditions, and to update the acoustic emission background database under the conditions.

[0057] Although this disclosure has been shown and described with reference to specific exemplary embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made to this disclosure without departing from the spirit and scope of the disclosure as defined by the appended claims and their equivalents. Therefore, the scope of this disclosure should not be limited to the above embodiments, but should be defined not only by the appended claims, but also by their equivalents.

Claims

1. A method for enhancing the solar heating efficiency of a microchannel flat plate solar collector, characterized in that, Includes the following steps: S1: Establish a synchronous acquisition system for microchannel local connection areas, operating status parameters, acoustic emission signals, local temperature and fluid operation parameters, and establish a device parameter database and detection area topology; S2: Under normal conditions, establish a state condition acoustic emission background database based on the operating state vector, extract effective acoustic emission events and construct spatiotemporal clustering features, and construct nonlinear acoustic emission state indices. S3: Establish a calibration relationship between nonlinear acoustic emission state index and critical state of interlayer connection interface using interlayer connection interface, and identify the pre-critical state of interlayer connection interface online. S4: Implement constrained local heat transfer fluid flow rate regulation for the microchannel group mapped to the detection area corresponding to the pre-critical state, and perform closed-loop control; S5: Evaluate the changes in effective heating energy, heat collection efficiency, pump energy consumption, net heating energy and acoustic emission status indicators before and after adjustment under operating conditions, and update the acoustic emission background database under operating conditions.

2. The method for enhancing the solar heating efficiency of a microchannel flat plate solar collector according to claim 1, characterized in that, The establishment of a synchronous acquisition system for microchannel local connection regions, operating status parameters, acoustic emission signals, local temperature, and fluid operation parameters, and the establishment of an equipment parameter database and detection area topology, includes: dividing the interlayer connection interface along the microchannel arrangement direction into... Each detection area corresponds to a microchannel group formed by adjacent microchannels, establishing a fixed mapping relationship between the detection areas and the microchannel groups; an acoustic emission sensor is set in each detection area to collect the raw acoustic emission voltage signal. Local heat absorber temperature sensors are installed on the surface of the heat absorber in each detection area to collect the local heat absorber temperature. Collect the inlet temperature of the solar collector. collector outlet temperature Total mass flow rate Local microchannel mass flow rate Collector pressure difference Pressure difference between the two ends of the circulating pump Solar irradiance Ambient temperature Obtain the density of the heat transfer fluid. Specific heat capacity of heat transfer fluid Circulating pump efficiency Effective light-receiving area of ​​the solar collector Establish an adjacency matrix for the detection region. ,in Indicates the first The detection area and the first Adjacent detection areas Indicates the first The detection area and the first The detection areas are not adjacent.

3. The method for enhancing the solar heating efficiency of a microchannel flat plate solar collector according to claim 1, characterized in that, The process of establishing a state-conditional acoustic emission background database based on the operating state vector under normal conditions includes: defining the operating state vector. ,in , , , ; This is a reference value for solar irradiance. This is a reference value for temperature difference. This is a reference value for total mass flow rate. The collector pressure differential reference value is used; during the operation cycle where independent testing confirms that the interlayer connection interface is in a normal state, the initial valid acoustic emission events are extracted using preset initial acoustic emission event identification rules, and the statistical time window is calculated. Initial effective acoustic emission event rate within Logarithmic transformation of the initial effective acoustic emission event rate is given by the following formula: ,in This is the logarithmic transformation value of the initial effective acoustic emission event rate. To prevent positive values ​​with a logarithm of zero from being corrected, the operating state vector obtained from the normal operating cycle will be used as the correction parameter. Initial effective acoustic emission event rate Logarithmic transformation value of the initial effective acoustic emission event rate Store the acoustic emission background database to form state conditions; obtain the current running state. The first in the state-condition acoustic emission background database The running state vector of a normal sample Normalized distance between ; Calculate nonlinear kernel weights The formula is: ,in The state neighborhood scale parameter, The number of normal samples used in the calculation. Indicates the current running status With the The running state vector of a normal sample The normalized distance between them is obtained using the same distance calculation method; nonlinear kernel weights are used. Calculate the logarithmic baseline of the normal event rate Dispersion with normal state The calculation formula is: and ; Calculate the acoustic emission background reference under state conditions When the calculation result is less than zero, Set it to zero.

4. The method for enhancing the solar heating efficiency of a microchannel flat plate solar collector according to claim 1, characterized in that, The extraction of valid acoustic emission events and the construction of spatiotemporal clustering features include: based on the logarithm of the normal event rate benchmark. Dispersion with normal state Build dynamic event trigger thresholds The formula is: ,in Background deviation control coefficient; for the original acoustic emission voltage signal After bandpass filtering, removal of fixed-frequency mechanical vibration components, and amplitude normalization, the amplitude of the original acoustic emission voltage signal exceeds the dynamic event triggering threshold. When the minimum duration, maximum duration, and event dead time requirements are met, the signal segment is defined as a valid acoustic emission event; the current time window is statistically analyzed. Inner The set of valid acoustic emission events in a detection area and current effective event rate ; Calculate the standardized outliers of the state The formula is: ,in It is a dimensionless stable term; calculate the event-time coordination between adjacent detection regions. and normalized synergy The formula is and ;in For event time coordination window, It is a dimensionless stable term; obtain the first term. The detection area and the first Spatial distance between the centers of each detection area Spatial weights are constructed using the adjacency matrix and spatial distance between detection regions. The formula is: ,in For spatial correlation scale; calculate spatiotemporal clustering factor The formula is: ,in For the first The set of adjacent detection regions of a detection region.

5. The method for enhancing the solar heating efficiency of a microchannel flat plate collector according to claim 1, characterized in that, The construction of the nonlinear acoustic emission state index includes: standardizing the state anomalies. Convert to non-negative smoothed risk The formula is: ,in Dimensionless shape coefficients; construct spatiotemporal co-enhancing terms The formula is: ,in For the nonlinear coefficients of the spatiotemporal coordination enhancement term, The exponent for spatiotemporal coordination enhancement; constructing nonlinear interaction terms. The formula is: ,in For nonlinear interaction term coupling coefficients, The exponent of the nonlinear interaction term is obtained; Nonlinear acoustic emission state index of each detection area The formula is: .

6. The method for enhancing the solar heating efficiency of a microchannel flat plate solar collector according to claim 1, characterized in that, The process of establishing a calibration relationship between nonlinear acoustic emission state indices and the critical state of interlayer connection interfaces includes: preparing a calibration microchannel flat-plate solar collector with the same material combination, microchannel structure, interlayer connection process, and sensor arrangement as the microchannel flat-plate solar collector to be monitored; applying thermal cycling conditions to the calibration microchannel flat-plate solar collector and simultaneously collecting data; and calculating the nonlinear acoustic emission state indices of the calibration microchannel flat-plate solar collector. During the preset thermal cycling phase, the thermal cycling operation is stopped, and the area of ​​minimal misalignment is obtained using industrial CT. Total area of ​​interlayer connection interfaces and the area of ​​the largest continuous misfit region ; Calculate the proportion of micro-misfit area and micro-disconnection connectivity The formula is: and , A positive correction parameter; based on a preset area threshold. and connectivity threshold Determine the calibration stage for the critical state of continuous mis-adhesion, when the proportion of micro-mis-adhesion area... Greater than or equal to the preset area threshold value And slight disconnection connectivity Greater than or equal to the critical value of connectivity At that time, the corresponding thermal cycle stage is determined as the continuous misalignment critical state calibration stage; the calibration corresponding to the continuous misalignment critical state calibration stage is performed using the nonlinear acoustic emission state index of the microchannel flat plate collector. Recorded as a critical indicator for continuous loss of interest Establish normalized critical process variables The formula is: ,in To establish a benchmark for the nonlinear acoustic emission performance of microchannel flat-plate solar collectors for calibration. This is a dimensionless stable term; based on the normalized critical process variable of the microchannel flat plate solar collector before the calibration stage of continuous misalignment critical state. The statistical distribution selects the pre-critical proportion Obtain pre-critical indicators The calculation formula is: Statistical calibration of microchannel flat plate solar collectors during the pre-critical state The statistical distribution of the rate of change yields the maximum permissible state growth rate. ;Will The rate of change continuously exceeds the maximum permissible rate of increase. Furthermore, a state exhibiting an accelerating growth trend is defined as a rapid development state. This rapid development state... The statistical threshold of the rate of change as a threshold for rapid development ,Will , , , Store it.

7. The method for enhancing the solar heating efficiency of a microchannel flat plate collector according to claim 1, characterized in that, The online identification of the pre-critical state of the inter-layer connection interface includes: real-time acquisition of the first... Nonlinear acoustic emission state index of each detection area ; Calculate short-period changes and long-term changes The calculation formula is: and ;in For the current time, To calculate a longer time window for short-cycle calculations, For long-period calculations, the time window is long. ; Calculate trend consistency The formula is: ,in A dimensionless stable term; construct a nonlinear evolution factor. The formula is: ,in It is a dimensionless state scale parameter. The coefficient is a dimensionless coupling coefficient; when and and At that time, the judgment of the first Each detection area enters a pre-critical state; when Time to determine the first Each detection area enters a critical state of continuous loss of adhesion; when Maintain normal monitoring status; when but It was determined to be in a high-level stable state.

8. The method for enhancing the solar heating efficiency of a microchannel flat plate solar collector according to claim 1, characterized in that, The constrained local heat transfer fluid flow rate regulation and closed-loop control implemented for the microchannel group mapped to the detection region corresponding to the pre-critical state includes: obtaining the basic mass flow rate of the microchannel group corresponding to the detection region entering the pre-critical state. Define the criticality variable. The formula is: ; Calculate the temperature change state of the local heat absorber plate The formula is: ,in For the first The surface temperature of the heat absorber plate at the corresponding location of each detection area. Establish a calculation window for temperature changes; construct dimensionless thermal state variables. The formula is: ,in This is a normal temperature change scale. It is a dimensionless stable term; calculate the pressure safety margin. The calculation formula is: ,in The maximum allowable pressure difference for the solar collector. It is a dimensionless stable term; calculate the local flow increment. The formula is: ,in To maximize traffic increment, This is the criticality weighting coefficient. This is the thermal state weighting coefficient. For the critical degree of nonlinearity, The thermal nonlinearity index is used to calculate the target local mass flow rate. ,in For the target local mass flow rate, and These represent the minimum and maximum allowable mass flow rates for the local microchannel group, respectively; based on the temperature change state of the local absorber plate and Make feedback and adjustments when and When economic activity resumes, when and At this time, it is permissible to continue increasing the local flow rate under pressure safety constraints, when Stop modifying local flow at a certain time; The upper limit of normal temperature variation is the economic operating flow rate, which is the recommended flow rate with the lowest energy consumption. As a safe threshold for the rate of temperature decrease, the Economic operating flow and Retrieved from the device parameter database; when Stop increasing the local flow when the time comes; When an anomaly occurs, it should be handled accordingly.

9. A method for enhancing the solar heating efficiency of a microchannel flat plate solar collector according to claim 1, characterized in that, The evaluation of changes in effective heating energy, heat collection efficiency, pump energy consumption, net heating energy, and acoustic emission state indicators before and after adjustment under matching operating conditions, and the updating of the state-condition acoustic emission background database, includes: calculating effective heat power. The formula is: ; Calculate the heat collection efficiency The formula is: Heat collection efficiency exist Calculated within the evaluation range, Calculate the minimum effective irradiance threshold; calculate the input power of the circulating pump. The formula is: , ; Calculate the net effective heating power The formula is: Construct the running state vectors before and after adjustment and calculate the running state distance, selecting only those with a running state distance less than or equal to... Pairing and evaluation are conducted within a time window. Set a threshold for allowed running states; define a matching window. The distance between the operating states before and after adjustment is less than or equal to A continuous time window; in the matching window Internal calculation of effective thermal energy Pump energy consumption The formula is and Calculate net heating energy The formula is: Define the net heating efficiency coefficient. The formula is: , A positive energy stabilization term; define the acoustic emission state improvement coefficient. The formula is: ,in To adjust the mean value of the acoustic emission state index, To adjust the mean values ​​of the front acoustic emission state parameters; a local temperature change improvement coefficient is defined. The formula is: ,in To adjust the average temperature change of the local heat absorber plate after adjustment, To adjust the average temperature change of the local heat absorber plate; when simultaneously satisfying , or The continued growth trend has been suppressed. If the preset net heating maintenance ratio is achieved and the local flow limit and pressure safety limit are not exceeded during the control period, the corresponding operating cycle of this adjustment will be marked as an effective control cycle; only data that meets the normal state requirements within a continuous time window will be marked as normal background candidate data, using exponential decay weighting. Update the state condition acoustic emission background database. The calculation formula is: , The time interval between the sample and the current time. Update the time scale for the background.

10. A solar heating efficiency enhancement system for a microchannel flat plate solar collector, used to implement the solar heating efficiency enhancement method for a microchannel flat plate solar collector as described in any one of claims 1-9, characterized in that, Also includes: The synchronous acquisition and topology construction module is used to establish a synchronous acquisition system for microchannel local connection areas, operating status parameters, acoustic emission signals, local temperature and fluid operation parameters, and to establish a device parameter database and topological relationships of the detection area; The acoustic emission background and index module is used to establish a state-condition acoustic emission background database based on the operating state vector under normal conditions, extract effective acoustic emission events and construct spatiotemporal clustering features, and construct nonlinear acoustic emission state indices. The pre-critical state identification module is used to establish a calibration relationship between the nonlinear acoustic emission state index and the critical state of the interlayer connection interface using the interlayer connection interface, and to identify the pre-critical state of the interlayer connection interface online. The local flow closed-loop control module is used to implement constrained local heat transfer fluid flow regulation for the microchannel group mapped to the detection area corresponding to the pre-critical state, and to perform closed-loop control. The heating efficiency evaluation and update module is used to evaluate changes in effective heating energy, heat collection efficiency, pump energy consumption, net heating energy, and acoustic emission status indicators before and after adjustment under operating conditions, and to update the acoustic emission background database under the conditions.

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