Building curtain wall material heat conductivity coefficient auxiliary analysis test method and system

Abstract

The invention belongs to the technical field of building material detection, and particularly relates to a building curtain wall material heat conductivity coefficient auxiliary analysis test method and system. The method comprises the steps of collecting temperature data in a heat conduction process, and identifying a stable fluctuation section based on a change trend of the temperature data to determine a heat conduction starting point and an effective section; based on the temperature data of the delay reference point before the heat conduction starting point and the temperature data in the effective section, an initial heat conduction coefficient is obtained through calculation; and judging whether the effective section meets a preset temperature stability condition or not, if not, determining a compensation correction according to the temperature deviation, and calculating according to the initial heat conductivity coefficient and the compensation correction to obtain a corrected heat conductivity coefficient. According to the method, by dynamically determining an effective section and introducing a temperature instability compensation correction mechanism, the accuracy, robustness and environmental adaptability of a test result are improved, and meanwhile, the consistency and repeatability of the result are ensured through automatic processing.

Description

Technical Field

[0001] This invention belongs to the field of building material testing technology, specifically relating to an auxiliary analysis and testing method and system for the thermal conductivity of building curtain wall materials. Background Technology

[0002] With the continuous development of green building and building energy-saving technologies, building curtain walls, as a key component of modern building envelopes, play a decisive role in the overall energy consumption of buildings and the comfort of indoor environments. The thermal conductivity of curtain wall materials is the core indicator for evaluating their thermal insulation capabilities.

[0003] Existing technologies for measuring the thermal conductivity of building curtain wall materials have many inherent technical defects and limitations. The measurement system itself introduces significant systematic errors. For example, there are unavoidable gaps between the test support used to fix the sample and the sample, which create additional thermal bridging effects. The test equipment itself also generates and dissipates heat during operation. These heat flows that are not transferred through the sample seriously interfere with the main thermal path of the measurement. Together, these factors cause the measured heat flux to fail to accurately reflect the heat transfer characteristics of the material itself, fundamentally reducing the accuracy of the measurement results. Summary of the Invention

[0004] The purpose of this invention is to provide an auxiliary analysis and testing method for the thermal conductivity of building curtain wall materials. This method avoids the large errors in the thermal conductivity process of the material under test due to the rapid temperature conduction between the heating element and the heated body of the testing plate, which makes it impossible to accurately control the temperature difference between the two ends of the material under test.

[0005] This invention is achieved through the following technical solution: Beneficial effects This invention provides an auxiliary analysis and testing method for the thermal conductivity of building curtain wall materials. It collects temperature data during the heat conduction process, identifies stable fluctuation zones based on the temperature data's changing trends, and determines the endpoint of these stable fluctuation zones as the heat conduction starting point, thus identifying the effective zone. This mechanism, based on actual data to dynamically determine the effective zone, objectively captures the heat conduction starting point of the effective heat conduction process, avoiding systematic errors introduced by manual settings or fixed time windows. This ensures the accuracy of the data foundation upon which subsequent thermal conductivity calculations rely, thereby improving the accuracy and reliability of the test results.

[0006] After calculating the initial thermal conductivity, this invention performs a thermal conductivity correction calculation. This process first determines whether the temperature data within the effective range meets the preset temperature stability conditions. If not, it calculates the compensation correction amount based on the temperature deviation between the actual temperature data and the preset target stable temperature distribution, and uses the compensation correction amount to correct the initial thermal conductivity. This mechanism can actively identify and quantify the temperature instability caused by environmental fluctuations during the test, and effectively compensate for the resulting errors. This mechanism overcomes the shortcomings of traditional methods in terms of accuracy degradation under non-ideal test conditions, and enhances the robustness and environmental adaptability of the test method.

[0007] This invention constructs the testing process into automated steps, including data acquisition, determination of the effective section, calculation of thermal conductivity, calculation of thermal conductivity correction, and result output. The determination of the effective section and the calculation of the compensation correction both rely on preset objective standards and preset calculation models, requiring no manual intervention. Through this fully automated data processing and analysis, the uncertainty introduced by the subjective judgment of the testers is eliminated, ensuring the consistency and repeatability of the test results, while shortening the data analysis time and improving the overall testing efficiency. Attached Figure Description

[0008] Figure 1 This is a flowchart of the testing method included in Embodiment 1 of the present invention. Detailed Implementation

[0009] Example 1 This embodiment provides an auxiliary analysis and testing method for the thermal conductivity of building curtain wall materials. This method aims to improve the accuracy and reliability of test results through precise data analysis and dynamic correction. The method of this embodiment includes the following steps: Step 1: Data Acquisition Step. In this step, multiple temperature sensors are placed on the material under test, the heating element of the detection plate in thermal contact with the material under test, and the heated body of the detection plate in thermal contact with the material under test. The temperature data of the three are collected in real time during the heat conduction process. The temperature data is continuously recorded at a preset sampling frequency to form high-density time series data, which provides a basis for subsequent refined analysis.

[0010] Step 2: Test Section Division Step. Based on temperature data, the heat conduction process is divided into multiple test sections according to the trend of temperature data changes. The division can be based on the turning points in the trend of temperature data changes, such as the turning point from gradual heating to rapid heating, or the turning point from heating to cooling. In this way, the complete heat conduction process is decomposed into several stages with different thermodynamic characteristics.

[0011] Step 3: Determining the effective segment. This step is the core of ensuring the accuracy of the test. Its purpose is to identify the effective segment from multiple test segments. The effective segment refers to the time segment from the final heat conduction start point to the final heat conduction end point of the heat conduction process. The data in this segment is used for the core thermal conductivity calculation.

[0012] This step can be further broken down as follows: Unstable test sections are identified and eliminated to obtain stable fluctuation sections. This process is used to determine the stable fluctuation section corresponding to the preparatory stage before the system reaches thermal equilibrium before the start of the heat conduction process. The stable fluctuation section refers to a specific time segment in which the system temperature fluctuates regularly and with small amplitudes around a certain reference value before the start of the formal heat conduction process, indicating that the system has reached the initial thermal equilibrium state. Specifically, based on temperature data, the rate of temperature change between adjacent data points is calculated. The inflection point of the alternating positive and negative changes in the rate of temperature change is identified as an alternation inflection point. Based on the direction of temperature change before and after the alternation inflection point, the alternation inflection point where the temperature change trend changes from decreasing to increasing or from increasing to decreasing is divided into... Positive and negative inflection points are identified based on preset screening criteria. These criteria are one or more sets of numerical standards used to identify a series of consecutive, alternating positive and negative inflection points that characterize stable fluctuations from all alternating inflection points. For example, the criteria may include the number of consecutive positive and negative inflection points or the minimum temperature difference between inflection points. This process filters out a series of consecutive, alternating positive and negative inflection points to remove random temperature noise and identify segments with regular small fluctuations. The process also determines whether the time interval between adjacent positive and negative inflection points within a group meets a preset time interval standard. If so, the segment defined by the start and end points of that time interval is identified as a stable fluctuation segment.

[0013] The endpoint of the stable fluctuation segment is determined as the heat conduction starting point. To ensure the effectiveness of the selected heat conduction starting point, verification is required. The test temperature range corresponding to the stable fluctuation segment is compared with the preset heat conduction starting point screening conditions. The heat conduction starting point screening conditions may include requiring the average temperature of the segment to be within a preset initial temperature range. If the test temperature range meets the heat conduction starting point screening conditions, the endpoint of the stable fluctuation segment is determined as the heat conduction starting point. If the test temperature range does not meet the heat conduction starting point screening conditions, the steps of claim 3 are repeated based on the temperature data until a stable fluctuation segment that meets the heat conduction starting point screening conditions is determined, and the heat conduction starting point is determined. If multiple stable fluctuation segments that meet the heat conduction starting point screening conditions are determined, the first stable fluctuation segment that appears in the time series is selected; the endpoint of the first stable fluctuation segment is determined as the final heat conduction starting point.

[0014] The heat conduction endpoint is determined, which is the precise time point at which the effective heat conduction process ends. The determination of the heat conduction endpoint corresponds to the determination of the heat conduction starting point. Based on a preset temperature change threshold, which refers to a pre-set critical value of temperature change rate or temperature difference, when the actual measured temperature change is lower than this value, it can be preliminarily judged that the heat conduction process has tended to stabilize or end. The temperature data is judged to preliminarily determine the heat conduction endpoint.

[0015] The time interval between the heat conduction start point and the heat conduction end point is determined as the effective interval. Based on the preset temperature adjustment delay time, which refers to a preset time value used to quantify and compensate for the delay between the issuance of the control command and the actual occurrence of the thermal response of the system, or the inherent thermal inertia effect of the system, the positions of the initially determined heat conduction start point and the initially determined heat conduction end point are corrected. This correction is used to compensate for the thermal inertia of the physical system or the response delay of the control system, thereby obtaining the final heat conduction start point and the final heat conduction end point. The time interval between the final heat conduction start point and the final heat conduction end point is the effective interval.

[0016] Step 4: Thermal Conductivity Calculation. In this step, the initial thermal conductivity of the material under test is calculated based on the temperature data at the delayed reference point before the thermal conductivity initiation point and the temperature data within the effective range. Specifically, a delayed reference point is determined before the thermal conductivity initiation point. This reference point is used to obtain a stable initial temperature reference unaffected by the main heat flow. The time difference between the thermal conductivity initiation point and the delayed reference point is defined as the thermal conductivity delay. The temperature corresponding to the delayed reference point and the temperature at a certain moment within the effective range are obtained, and the difference between the two is defined as the instantaneous temperature difference. Based on the thermal conductivity delay and the instantaneous temperature difference, the instantaneous thermal conductivity value is calculated. Based on the instantaneous thermal conductivity value, the instantaneous temperature difference, and the thermal conductivity delay, the initial thermal conductivity is calculated using a preset calculation model. The preset calculation model refers to a calculation model used to calculate the initial thermal conductivity of a material based on transient thermal response data. Its specific formula is as follows:

[0017] In the formula, This represents the initial thermal conductivity, which means the thermal conductivity of the material under the current test conditions without compensation for unsteady-state effects. This indicates the heating plate power, which means the stable thermal power applied by the heating element of the test plate during the test; This indicates the thickness of the material to be measured, which means the geometric thickness of the material in the direction of heat flow. This represents the cross-sectional area of ​​the material under test, which is the effective heat transfer area of ​​the material under test perpendicular to the heat flow direction. Indicates instantaneous temperature difference, which means the temperature difference between the two sides of the material at a certain calculation moment within the effective range; This indicates the thermal conduction delay, which is the time lag from the reference state to the start of effective thermal conduction. It is used to evaluate the transient response of the system. The system characteristic time constant is an inherent parameter that characterizes the time required for the test system (including heating, sensing, and the material under test) to reach thermal equilibrium. It is a preset value.

[0018] Step 5: Compensation Correction Calculation Step. Under specific test conditions, such as when the material under test is thick or the test time is limited, the system may not achieve ideal steady-state heat conduction. This step aims to compensate for this non-ideal state. Specifically, based on the temperature data of the effective section, it is determined whether the effective section meets the preset temperature stability condition. The preset temperature stability condition is as follows: within the effective section, sampling points with temperatures higher than the preset high-temperature threshold are defined as high-temperature sampling points; the number of consecutive sampling points and the number of high-temperature sampling points are counted; if the number of consecutive sampling points is more than three times the number of high-temperature sampling points, and the proportion of sampling points with temperatures lower than the high-temperature threshold is greater than 60% among the consecutive sampling points, then it is determined that the preset temperature stability condition is met. If the effective section meets the preset temperature stability condition, the compensation correction is zero. If the effective section does not meet the preset temperature stability condition, the compensation correction is determined based on the temperature deviation between the temperature data within the effective section and the preset target stable temperature distribution. For example, the compensation correction is calculated by fitting a function to the deviation between the temperature data within the effective section and the preset target stable temperature distribution.

[0019] Step Six: Corrected Thermal Conductivity Output Step. Based on the initial thermal conductivity and the compensation correction amount, the final thermal conductivity value is obtained by combining (e.g., adding or subtracting). This value is closer to the true thermal conductivity of the material under ideal steady-state conditions. The corrected thermal conductivity is calculated and output.

[0020] This embodiment solves the problem of difficulty in accurately controlling the temperature difference between the two ends of the material under test due to the fast temperature conduction speed between the heating element and the heated body of the testing plate. It reduces the test error of the material under test during the heat conduction process. At the same time, this embodiment avoids the influence of heat dissipation from the heated body of the testing plate on the temperature of the heating element of the testing plate, thereby obtaining a reliable testing environment, realizing accurate testing of the thermal conductivity of building curtain wall materials, saving testing time and cost, and facilitating its widespread application.

[0021] Example 2 To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely for explaining the invention and are not intended to limit the scope of protection of the invention. This embodiment provides a thermal conductivity testing system for building curtain wall materials. This system is used to execute the above-described auxiliary analysis and testing method for the thermal conductivity of building curtain wall materials. It can automatically identify the effective data segments in the heat conduction process and compensate and correct the test results under non-ideal stable conditions, thereby improving the accuracy and reliability of thermal conductivity testing. In specific implementation, it can be deployed on computing devices including personal computers, servers, workstations, or embedded industrial control computers, and communicate with temperature sensors and testing devices through data interfaces. Logically, this system can be divided into the following collaborative modules: The data acquisition module connects to the temperature sensing device installed in the test environment to collect temperature data during the heat conduction process in real time or periodically. It collects and records temperature time series data from three key locations: the material under test, the heating element of the detection plate as a heat source, and the heated body of the detection plate as a heat sink. The collected temperature data is formatted and stored for subsequent analysis and processing by the modules.

[0022] The effective segment determination module's core task is to automatically determine the effective segment for subsequent thermal conductivity calculations based on the raw temperature data collected by the data acquisition module. Its workflow is as follows: It analyzes the time series of temperature data to identify stable fluctuation segments. This is done by calculating the rate of temperature change between adjacent data points and monitoring the sign of this rate to identify the trend of temperature change. When the rate of temperature change changes from negative to positive, a positive inflection point is marked; when it changes from positive to negative, a negative inflection point is marked. The module then filters out groups consisting of consecutive and alternating positive and negative inflection points. For each group, it determines whether the time interval between adjacent inflection points within the group meets a preset time interval standard. If the standard is met, it means that the temperature has entered a state of regular, small fluctuations. The segment defined by the interval is determined as a stable fluctuation segment. After determining the stable fluctuation segment, the thermal conductivity starting point is determined. If multiple stable fluctuation segments may be identified, the first stable fluctuation segment that appears in the time series will be selected, and its end time will be determined as the thermal conductivity starting point. This aims to capture the initial stage when heat begins to stably penetrate the material under test and determine the thermal conductivity ending point. The determination of the thermal conductivity ending point can be based on various strategies, such as when the test has been carried out for a preset total time, or when the temperature change trend deviates significantly from the stable fluctuation state again. This is only a preferred implementation method and does not constitute a limitation of the present invention. The time segment between the determined thermal conductivity starting point and the thermal conductivity ending point is defined as the effective segment for thermal conductivity calculation, and the segment information is passed to the thermal conductivity correction module.

[0023] The thermal conductivity correction module, upon receiving the definition of the effective section, performs the core thermal conductivity correction calculation. This calculation process is broken down into the following steps: First, it calculates the initial thermal conductivity. A delay reference point is located on the time axis before the thermal conductivity start point, and the time difference between this point and the thermal conductivity start point is defined as the thermal conductivity delay. The temperature at a certain moment within the effective section and the corresponding temperature at the delay reference point are obtained, and the difference between these two temperature values ​​is defined as the instantaneous temperature difference. Based on this instantaneous temperature difference and the thermal conductivity delay, an instantaneous thermal conductivity value is calculated. A preset calculation model is called, which integrates parameters such as the instantaneous thermal conductivity value, instantaneous temperature difference, and thermal conductivity delay to calculate the initial thermal conductivity. Second, it determines the compensation correction amount. The module judges whether the temperature data within the effective section meets the preset temperature stability condition. Specifically, this condition is: sampling temperatures within the effective section that are higher than a preset high-temperature threshold. The point is defined as a high-temperature sampling point, and it is determined whether the total number of sampling points in the effective section is greater than three times the number of high-temperature sampling points, and whether the proportion of sampling points with a temperature value lower than the high-temperature threshold is greater than 60%. If the judgment result is yes, it indicates that the heat conduction process is relatively stable, and the compensation correction amount can be determined as a zero value or a very small default value. If the judgment result is no, it indicates that the heat conduction process is in a non-ideal unsteady state. The module will determine a non-zero compensation correction amount based on the temperature deviation between the actual temperature data in the effective section and a preset target stable temperature distribution. The magnitude of the compensation correction amount is related to the degree of temperature deviation. The third step is to calculate the corrected thermal conductivity. The module performs the final calculation based on the initial thermal conductivity obtained in the first step and the compensation correction amount determined in the second step. For example, the final corrected thermal conductivity is obtained by adding the initial thermal conductivity and the compensation correction amount or by performing other preset function operations.

[0024] The output module, which is the final interactive interface of the system, receives the corrected thermal conductivity calculated by the thermal conductivity correction module. After receiving the value, the output module presents it in a user-friendly way, such as displaying it on a graphical user interface, generating a test report document, or storing it in a database for historical traceability and quality control analysis.

[0025] Through the collaborative work of the aforementioned data acquisition module, effective section determination module, thermal conductivity correction module, and output module, the system in this embodiment can automatically process the raw temperature data in thermal conductivity testing, intelligently select the key data segments that best reflect the thermal conductivity characteristics of the material, and quantitatively correct the unsteady-state process caused by fluctuations in experimental conditions or nonlinear responses of the material, ultimately outputting a more accurate and reliable thermal conductivity value. This system is particularly suitable for performance evaluation scenarios of building curtain wall materials where high testing accuracy is required and the experimental environment is easily disturbed, thus improving testing efficiency and the credibility of the results.

[0026] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for auxiliary analysis and testing of the thermal conductivity of building curtain wall materials, characterized in that, include: Based on the temperature data during the heat conduction process, determine the effective section for calculating the thermal conductivity. Perform thermal conductivity correction calculations for the effective section. The thermal conductivity correction calculations include: The initial thermal conductivity is calculated based on the temperature data within the effective section and the temperature data at the delayed reference point before the thermal conduction start point of the effective section. Determine whether the effective section meets the preset temperature stability conditions, and determine the compensation correction amount based on the determination result. If the effective section does not meet the preset temperature stability conditions, the compensation correction amount is determined based on the temperature deviation between the temperature data in the effective section and the preset target stable temperature distribution. The corrected thermal conductivity is calculated and output based on the initial thermal conductivity and the compensation correction amount.

2. The auxiliary analysis and testing method for the thermal conductivity of building curtain wall materials according to claim 1, characterized in that, Determining the effective segment includes: identifying stable fluctuation segments based on the changing trends of temperature data; determining the end time of the stable fluctuation segment as the heat conduction start point; determining the heat conduction end point, and defining the time segment between the heat conduction start point and the heat conduction end point as the effective segment.

3. The auxiliary analysis and testing method for the thermal conductivity of building curtain wall materials according to claim 2, characterized in that, The identification of stable fluctuation segments includes: calculating the rate of temperature change between adjacent data points based on temperature data, and identifying alternating inflection points based on the alternating positive and negative changes in the rate of temperature change; filtering out continuous and alternating groups of positive and negative inflection points, and determining whether the time interval between adjacent inflection points in the group meets the preset time interval standard; if it meets the standard, the segment defined by the time interval is determined as a stable fluctuation segment.

4. The auxiliary analysis and testing method for the thermal conductivity of building curtain wall materials according to claim 2, characterized in that, The method also includes: if multiple stable fluctuation segments are identified, the first stable fluctuation segment that appears in the time series is selected, and its endpoint is determined as the heat conduction starting point.

5. The auxiliary analysis and testing method for the thermal conductivity of building curtain wall materials according to claim 1, characterized in that, The initial thermal conductivity was calculated by determining the time difference between the thermal conductivity initiation point and the delay reference point as the thermal conductivity delay. Obtain the temperature corresponding to the delay reference point and the temperature at a certain moment within the effective segment, and determine the difference between the two as the instantaneous temperature difference; calculate the instantaneous thermal conductivity value based on the thermal conduction delay and the instantaneous temperature difference; calculate the initial thermal conductivity coefficient based on the instantaneous thermal conductivity value, the instantaneous temperature difference, and the thermal conduction delay through a preset calculation model.

6. The auxiliary analysis and testing method for the thermal conductivity of building curtain wall materials according to claim 1, characterized in that, The preset temperature stability condition is: within the effective range, sampling points that are higher than the preset high temperature threshold are defined as high temperature sampling points; Furthermore, the total number of sampling points within the effective section is more than three times the number of high-temperature sampling points, and among the sampling points within the effective section, the proportion of sampling points with temperature values ​​below the high-temperature threshold is greater than 60%.

7. A system for testing the thermal conductivity of building curtain wall materials, characterized in that, include: The data acquisition module is used to collect temperature data of the material under test, the heating element of the detection plate, and the heated body of the detection plate during the heat conduction process; The effective section determination module is used to determine the effective section for thermal conductivity calculation based on temperature data. A thermal conductivity correction module is configured to perform thermal conductivity correction calculations in response to the determination of the effective section by the effective section determination module. The thermal conductivity correction calculations include: The initial thermal conductivity is calculated, and the compensation correction amount is determined based on the judgment of whether the effective section meets the preset temperature stability conditions. The corrected thermal conductivity is calculated based on the initial thermal conductivity and the compensation correction amount. The output module is used to output the corrected thermal conductivity.

8. The thermal conductivity testing system for building curtain wall materials according to claim 7, characterized in that, The valid segment determination module is configured as follows: Identify stable fluctuation zones based on the changing trends of temperature data; The effective range is defined by determining the heat conduction start and end points based on the stable fluctuation range.

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