A method and system for auxiliary analysis and testing of the thermal conductivity coefficient of a building curtain wall material

Abstract

The present application belongs to the technical field of building material detection, and particularly relates to a kind of building curtain wall material heat conductivity coefficient auxiliary analysis test method and system.The method comprises: collecting temperature data in the heat conduction process, identifying stable fluctuation section based on the change trend of temperature data to determine the heat conduction starting point and 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, the initial heat conduction coefficient is calculated;Judge whether the effective section meets the preset temperature stability condition, if not, determine the compensation correction amount according to the temperature deviation, and calculate the corrected heat conduction coefficient according to the initial heat conduction coefficient and the compensation correction amount.The method improves the accuracy, robustness and environmental adaptability of the test results by dynamically determining the effective section and introducing the temperature instability compensation correction mechanism, and ensures the consistency and repeatability of the results through automatic processing.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of building material detection, and particularly relates to a building curtain wall material thermal conductivity auxiliary analysis test method and system. BACKGROUND

[0002] With the continuous development of green buildings and building energy-saving technologies, as a key component of modern building envelope structures, the thermal performance of building curtain walls plays a decisive role in the overall building energy consumption and indoor environmental comfort, and the thermal conductivity of curtain wall materials is a core index for evaluating their thermal insulation capacity.

[0003] The prior art has many inherent technical defects and limitations in measuring the thermal conductivity of building curtain wall materials, and the measurement system itself introduces significant systematic errors, such as the inevitable gaps between the detection bracket for fixing the sample to be measured and the sample, which form additional thermal bridge effects; the detection equipment itself also generates and emits heat during operation, which seriously interferes with the main heat path of the measurement, and together causes the measured heat flux to not truly reflect the heat transfer characteristics of the material itself, fundamentally reducing the accuracy of the measurement results. SUMMARY

[0004] The purpose of the present application is to provide a building curtain wall material thermal conductivity auxiliary analysis test method, which can avoid the temperature conduction speed between the detection plate heating body and the detection plate heated body being too fast, so that the temperature difference maintained at both ends of the material to be measured cannot be accurately controlled, resulting in a large error in the heat conduction process of the material to be measured.

[0005] The present application is achieved by the following technical solutions:

[0006] Advantages

[0007] The present application provides a building curtain wall material thermal conductivity auxiliary analysis test method, which collects temperature data during the heat conduction process, identifies a stable fluctuation section based on the change trend of the temperature data, determines the end point of the stable fluctuation section as the heat conduction starting point, and determines the effective section. This mechanism of dynamically determining the effective section based on actual data can objectively capture the heat conduction starting point of the effective heat conduction process, avoid the introduction of systematic errors caused by artificial setting or fixed time windows, ensure the accuracy of the data basis relied on subsequent thermal conductivity calculation, and thus improve the accuracy and reliability of the test results.

[0008] After the initial thermal conductivity coefficient calculation is completed, the present application performs thermal conductivity coefficient correction calculation, which firstly judges whether the temperature data in the effective section meets the preset temperature stability condition; if not, the compensation correction amount is calculated according to the temperature deviation between the actual temperature data and the preset target stable temperature distribution, and the initial thermal conductivity coefficient is corrected by using the compensation correction amount, which can actively identify and quantify the temperature instability state caused by environmental fluctuations in the test process, and effectively compensate the error caused thereby, thus overcoming the defects of the traditional method in the precision reduction under non-ideal test conditions, and enhancing the robustness and environmental adaptability of the test method.

[0009] The present application constructs the test process as an automatic processing step, including data acquisition, effective section determination, thermal conductivity coefficient calculation, thermal conductivity coefficient correction calculation and result output, the determination of the effective section and the calculation of the compensation correction amount both depend on the preset objective standard and the preset calculation model, without manual intervention, through the automatic data processing and analysis of the whole process, the uncertainty introduced by the subjective judgment of the test personnel is excluded, the consistency and repeatability of the test results are ensured, the data analysis time is shortened, and the overall test efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 is the test method flowchart included in embodiment 1 of the present application. DETAILED DESCRIPTION

[0011] Embodiment one

[0012] The present embodiment provides a kind of building curtain wall material thermal conductivity coefficient auxiliary analysis test method, which aims to improve the accuracy and reliability of test results by accurate data analysis and dynamic correction, the method of the present embodiment includes the following steps:

[0013] Step one: data acquisition step, in this step, by being arranged in the material to be measured, the heating body of the detection plate in thermal contact with the material to be measured and the heated body of the detection plate in thermal contact with the material to be measured Multiple temperature sensors, real-time acquisition of the temperature data of the three in the heat conduction process, temperature data is recorded continuously with preset sampling frequency, forms high-density time series data, provides basis for subsequent fine analysis.

[0014] Step two: test section division step, based on temperature data, according to the change trend of temperature data, the heat conduction process is divided into multiple test sections, the basis for division can be the nodes appearing in the change trend of temperature data, such as the turning point from gentle heating to rapid heating, or the turning point from heating to cooling, so as to decompose the complete heat conduction process into several stages with different thermodynamic characteristics.

[0015] Step three: effective segment determination step, which is the core of ensuring test accuracy, and the purpose is to identify the effective segment from multiple test segments, which refers to the time segment from the final heat conduction starting point to the final heat conduction ending point of the heat conduction process, and the data of this segment is used for the calculation of the thermal conductivity coefficient of the core.

[0016] This step is further refined as:

[0017] Identify and exclude unstable test segments to obtain stable fluctuation segments, which is used to determine the stable fluctuation segment corresponding to the preparation stage of the system reaching thermal equilibrium before the start of the heat conduction process, which refers to a specific time segment before the start of the formal heat conduction process, during which the system temperature alternately fluctuates regularly and slightly around a certain reference value, indicating that the system has reached an initial thermal equilibrium state. Specifically, based on temperature data, calculate the temperature change rate between adjacent data points, identify the turning point of the alternating change of the temperature change rate as the alternating inflection point, and divide the alternating inflection point into positive and negative inflection points according to the temperature change direction before and after the alternating inflection point, that is, the alternating inflection point where the temperature change trend changes from falling to rising or rising to falling. According to the preset screening condition, which refers to one or more numerical criteria for identifying a sequence of continuous and alternating positive and negative inflection points that represent stable fluctuations from all alternating inflection points, such as the number of consecutive positive and negative inflection points, the minimum temperature difference between inflection points, etc., screen out groups of consecutive and alternating positive and negative inflection points. This step is used to filter out random temperature noise to identify segments with regular small fluctuations. Determine whether the time interval between adjacent positive and negative inflection points in the group meets the preset time interval standard. If so, the segment defined by the start and end points of the time interval is determined as a stable fluctuation segment.

[0018] Determine the end time of the stable fluctuation segment as the heat conduction starting point. To ensure the effectiveness of the selected heat conduction starting point, verification is required. Compare the test temperature range corresponding to the stable fluctuation segment with the preset heat conduction starting point screening condition, which can include the requirement that the average temperature of the segment is within the preset initial temperature range. If the test temperature range meets the heat conduction starting point screening condition, the end point 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 condition, re-execute the above steps based on the temperature data until a stable fluctuation segment that meets the heat conduction starting point screening condition is determined, and the heat conduction starting point is determined. If multiple stable fluctuation segments that meet the heat conduction starting point screening condition are determined, select the first stable fluctuation segment that appears in the time sequence; determine the end point of the first stable fluctuation segment as the final heat conduction starting point.

[0019] 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.

[0020] 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.

[0021] 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:

[0022]

[0023] 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 being measured, which is 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; represents the thermal conduction delay, which means the time lag from the reference state to the start of effective thermal conduction, used to evaluate the degree of transient response of the system; represents the system characteristic time constant, which means an inherent parameter representing the time required for the test system (including heating, sensing, and the material to be tested) to reach thermal equilibrium, and is a preset value.

[0024] Step five: compensation correction amount calculation step, under certain test conditions, such as when the thickness of the material to be tested is large or the test time is limited, the system may not reach the 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 stabilization condition. The preset temperature stabilization condition is: in the effective section, define the sampling points higher than the preset high temperature threshold as high temperature sampling points; count the number of consecutive sampling points and the number of high temperature sampling points; 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 temperature values lower than the high temperature threshold in the consecutive sampling points is greater than sixty percent, it is determined that the preset temperature stabilization condition is met. If the effective section meets the preset temperature stabilization condition, the compensation correction amount is zero. If the effective section does not meet the preset temperature stabilization condition, the compensation correction amount is determined according to the temperature deviation between the temperature data in the effective section and the preset target stable temperature distribution. For example, by fitting the deviation between the temperature data in the effective section and the preset target stable temperature distribution with a function, the compensation correction amount is calculated.

[0025] Step six: correction of thermal conductivity coefficient output step, the final thermal conductivity coefficient value obtained by combining (such as adding or subtracting) the initial thermal conductivity coefficient and the compensation correction amount is closer to the true thermal conductivity coefficient of the material under ideal steady-state conditions. The corrected thermal conductivity coefficient is calculated and output.

[0026] The above steps solve the problem of difficult accurate control of the temperature difference between the two ends of the material to be tested due to the fast temperature conduction between the heating body and the heated body of the detection plate, reduce the test error of the material to be tested during the heat conduction process, and at the same time, avoid the influence of the heat dissipation of the heated body of the detection plate on the temperature of the heating body of the detection plate, so as to obtain a reliable test environment, realize accurate testing of the thermal conductivity coefficient of the building curtain wall material, and save test time and cost, facilitating popularization and application.

[0027] Embodiment two

[0028] In order to make the purposes, technical solutions and advantages of the present application clearer and more apparent, the present application will be further described in detail below in combination with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the protection scope of the present application. The embodiments provide a building curtain wall material thermal conductivity test system. The system is used to perform the above-mentioned building curtain wall material thermal conductivity auxiliary analysis test method, can automatically identify the effective data section in the heat conduction process, and compensate and correct the test results under the non-ideal steady state, thereby improving the accuracy and reliability of the thermal conductivity test. In specific implementation, the system can be deployed on a computing device including a personal computer, a server, a workstation or an embedded industrial control computer, and communicates with temperature sensors and test devices through a data interface. The system can be logically divided into the following modules that work cooperatively:

[0029] A data acquisition module is connected with temperature sensing devices installed in the test environment, and is used to collect temperature data in the heat conduction process in real time or periodically. Temperature time series data from three key positions, i.e. the material to be tested, the detection plate heating body as a heat source and the detection plate heat sink as a heat sink, are collected and recorded. The collected temperature data are formatted and stored for subsequent analysis and processing by the modules.

[0030] An effective segment determination module, the core task of which is to automatically determine an effective segment for subsequent thermal conductivity coefficient calculation according to the original temperature data collected by the data acquisition module, the working process of which is as follows: the time series of temperature data is analyzed to identify a stable fluctuation segment, which identifies the trend of temperature change by calculating the temperature change rate between adjacent data points and monitoring the sign of the change rate, marks a positive inflection point when the temperature change rate changes from negative to positive, and marks a negative inflection point when it changes from positive to negative. The module further screens groups composed of positive and negative inflection points that appear alternately and continuously in time. For each group, it determines whether the time interval between adjacent inflection points in the group meets a predetermined time interval standard. If the standard is met, it means that the temperature has entered a regular state of slight fluctuation, and the segment defined by the time interval is determined to be a stable fluctuation segment. After determining the stable fluctuation segment, the determination of the thermal conduction starting point is performed. In the case where multiple stable fluctuation segments are identified, the first stable fluctuation segment appearing in the time series is selected, and the end time of the segment is determined as the thermal conduction starting point. This is intended to capture the initial stage when heat begins to penetrate the material to be tested stably. The determination of the thermal conduction end point can be based on various strategies, for example, when the test has been conducted for a predetermined total duration, or when the temperature change trend again deviates significantly from the stable fluctuation state. This is only a preferred implementation and does not constitute a limitation on the present application. The time segment between the determined thermal conduction starting point and the thermal conduction end point is defined as the effective segment for thermal conductivity coefficient calculation, and the segment information is transmitted to the thermal conductivity coefficient correction module.

[0031] The thermal conductivity correction module receives the definition of the effective section and performs a core thermal conductivity correction calculation. The calculation process is divided into the following steps: first, calculate the initial thermal conductivity. Locate a delay reference point on the time axis before the thermal conduction starting point, and determine the time difference between the point and the thermal conduction starting point as the thermal conduction delay. Obtain the temperature at a certain time in the effective section and the temperature at the delay reference point, and determine the difference between the two temperature values as the instantaneous temperature difference. Based on the instantaneous temperature difference and the thermal conduction delay, an instantaneous thermal conduction value is calculated. A preset calculation model is called, which integrates the instantaneous thermal conduction value, the instantaneous temperature difference, and the thermal conduction delay to calculate the initial thermal conductivity. Second, determine the compensation correction. The module determines whether the temperature data in the effective section meets the preset temperature stability condition. The condition is that the sampling points in the effective section whose temperature is higher than a preset high temperature threshold are defined as high temperature sampling points, 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 whose temperature is lower than the high temperature threshold is greater than 60%. If the result is yes, it means that the thermal conduction process is relatively stable, and the compensation correction can be determined as a zero value or a very small default value. If the result is no, it means that the thermal conduction process is in a non-ideal non-steady state. The module will determine a non-zero compensation correction based on the temperature deviation between the actual temperature data in the effective section and a preset target stable temperature distribution. The size of the compensation correction is related to the degree of temperature deviation. Third, calculate the corrected thermal conductivity. The module calculates the final corrected thermal conductivity based on the initial thermal conductivity obtained in the first step and the compensation correction determined in the second step, for example, by adding the initial thermal conductivity and the compensation correction or performing other preset function operations.

[0032] The output module is the final interactive interface of the system. It 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 tracking and quality control analysis.

[0033] Through the cooperative work of the above-mentioned data acquisition module, effective section determination module, thermal conductivity correction module and output module, the system of the embodiment can automatically process the original temperature data in the thermal conductivity test, intelligently select the key data section that best reflects the thermal conductivity characteristics of the material, and quantitatively correct the non-steady state process caused by experimental condition fluctuations or material nonlinear response. Finally, a more accurate and reliable thermal conductivity value is output. The system is particularly suitable for building curtain wall material performance evaluation scenarios with high test precision requirements and experimental environment susceptible to interference, improving test efficiency and the credibility of the results.

[0034] The above descriptions are only the preferred embodiments of the present application, and are not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for assisting in the analysis of the thermal conductivity of building curtain wall materials, characterized in that, The method comprises: determining an effective section for the calculation of the thermal conductivity coefficient according to the temperature data in the heat conduction process; performing a thermal conductivity coefficient correction calculation for the effective section, the thermal conductivity coefficient correction calculation comprising: calculating an initial thermal conductivity coefficient based on the temperature data within the effective section and the temperature data at a delayed reference point before the start of heat conduction in the effective section; determining whether the effective section meets a preset temperature stabilization condition, and determining a compensation correction amount based on the determination result, wherein if the effective section does not meet the preset temperature stabilization condition, the compensation correction amount is determined according to the temperature deviation between the temperature data within the effective section and a preset target stable temperature distribution; calculating a corrected thermal conductivity coefficient according to the initial thermal conductivity coefficient and the compensation correction amount, and outputting the corrected thermal conductivity coefficient; wherein the determination of the effective section comprises: identifying a stable fluctuation section based on the trend of the temperature data; determining the start time of the heat conduction as the end time of the stable fluctuation section; determining the end time of the heat conduction, and determining the time section between the start time of the heat conduction and the end time of the heat conduction as the effective section; wherein the identification of the stable fluctuation section comprises: calculating the temperature change rate between adjacent data points based on the temperature data, and identifying an alternating inflection point according to the positive and negative alternating changes of the temperature change rate; screening out continuous and alternating positive and negative inflection point groups, and determining whether the time interval between adjacent inflection points in the group meets a preset time interval standard; if it meets, the section defined by the time interval is determined as the stable fluctuation section; wherein the calculation of the initial thermal conductivity coefficient comprises: determining the heat conduction delay as the time difference between the start time of the heat conduction and the delayed reference point; obtaining the temperature corresponding to the delayed reference point and the temperature at a certain time within the effective section, and determining the difference between the two as the instantaneous temperature difference; calculating the instantaneous heat conduction value based on the heat conduction delay and the instantaneous temperature difference; and calculating the initial thermal conductivity coefficient through a preset calculation model based on the instantaneous heat conduction value, the instantaneous temperature difference and the heat conduction delay.

2. The method according to claim 1, characterized in that, The method further comprises: if multiple stable fluctuation sections are determined, selecting the first stable fluctuation section appearing in the time sequence to determine the end time thereof as the start time of the heat conduction.

3. The method according to claim 2, wherein, The preset temperature stabilization condition is that, within the effective section, the sampling points higher than a preset high temperature threshold are defined as high temperature sampling points. Moreover, the total number of sampling points in the effective section is greater than three times the number of high temperature sampling points, and the proportion of sampling points with a temperature value lower than the high temperature threshold in the sampling points within the effective section is greater than 60%.

4. The system for testing the thermal conductivity of building curtain wall materials is applied to the method for testing the thermal conductivity of building curtain wall materials according to claim 1, wherein, The method comprises: a data acquisition module configured to collect temperature data of a material to be tested, a heating body of a detection plate and a heated body of the detection plate in a heat conduction process; an effective section determination module configured to determine an effective section for the calculation of a thermal conductivity coefficient according to the temperature data; a thermal conductivity coefficient correction module configured to perform a thermal conductivity coefficient correction calculation in response to the determination of the effective section by the effective section determination module, the thermal conductivity coefficient correction calculation comprising: calculating an initial thermal conductivity coefficient, determining a compensation correction amount based on the determination of whether the effective section meets a preset temperature stabilization condition, and calculating a corrected thermal conductivity coefficient according to the initial thermal conductivity coefficient and the compensation correction amount; an output module configured to output the corrected thermal conductivity coefficient.

5. The building curtain wall material thermal conductivity testing system according to claim 4, characterized in that, The effective section determination module is configured to: Identify stable fluctuation segments based on the change trend of temperature data; Determine the heat conduction starting point and the heat conduction ending point based on the stable fluctuation segments to define the effective segment.

Images