Application Of External Thermal Imaging Technology In Thermal Engineering Defects And Evaluation

Green energy saving building is the future development direction of the construction industry,but also has been vigorously promoted by the government,which is the building energy saving effect of the site testing technology has higher requirements.Infrared thermal imaging detection technology can be a good application in this area,and it is also a worthy of discussion.More than and 20 years ago,the scholars try to apply infrared imaging detection technology in building energy saving detection,but its application at the stage of qualitative analysis,and in the aspects of building energy saving do quantitative analysis,the research literature is not sufficient.Therefore,by combing the theory of infrared radiation and energy detection methods commonly used,and will try to use the infrared thermal imaging method for the detection of surface two together,and summarizes the calculation method of surface temperature,pointed out that the measurement error may exist.After that,this paper sums up the method of using infrared detection technology in the field of building energy saving effect.To further clarify the scope of application of the infrared thermal imaging method in the aspects of building energy saving detection,the author surveys the relevant literature,and the cell has been built residential area and the construction site were investigated.The analysis of possible detection methods in the application of infrared imaging problems.Through field research,the building envelope has a more clear understanding,and basically determine the infrared thermal imaging system for on-site detection of the scope of the application,including the following aspects:The thermal insulation performance,air tightness and average heat transfer coefficient of building envelope are measured,and the local construction details of the building can be detected.Based on the above range,this paper mainly studies the detection of air tightness and the average heat transfer coefficient in two aspects.First,in the research of the air tightness test,according to the classification of the air tightness grade,choose different buildings and take the infrared photo,and analyze the infrared thermal spectrum.By calculating the infrared data of the building,it is concluded that the infrared thermal imaging technology can be used to detect the air tightness of the building exterior window.To this end,this paper combined with the operation of technical procedures,developed a set of infrared detection technology in the application of infrared detection methods and processes.By means of the method and the process,it is applied to four engineering cases.The method and the process of the method are verified.Though the surface,infrared detection method is feasible on the theoretical analysis,it can be used as a qualitative analysis only in the practical application,and the quantitative analysis still needs to be improved.Then the average heat transfer coefficient detection is studied,the basic operation is to choose the appropriate winter,the outside temperature is low,the selected buildings for continuous testing,for 24 hours.Then the test results are analyzed,the average heat transfer coefficient of each time period is calculated.After comparing with the theoretical value,it is found that there is a large gap between the two.After analyzing the factors that may cause deviation,the parameters are corrected,and the final calculation method is obtained.Then the calculation method of the revised application in two typical building detection and calculation,and take the line heat transfer coefficient method as the contrast analysis,the final results show that detection in good insulation effect of new buildings is relatively close to the test results of two methods.Therefore,the accuracy of the application of infrared thermal imaging detection method in the detection of the average heat transfer coefficient of the building wall is ideal,the operation process is relatively easy.At the end of the paper,pointed out that the infrared thermal imager can be applied to the large-scale building energy saving effect evaluation,especially in the calculation of building heat consumption,convenient operation,high precision.After the detection of the thermal imaging system,the performance of the external walls of the building is intuitive to show,and according to the relevant data to quantify the calculation,the method is simple,reliable,and can be applied to the evaluation of building energy efficiency.