| China has a large stock of existing buildings,and the operating energy consumption is generally higher than that of new buildings.The energy-saving transformation of existing buildings is inevitable and has great carbon reduction potential,which is the key link to achieve the goal of "double carbon".At the same time,the energy consumption and indoor environment of existing buildings are significantly different due to different construction years and different operation and maintenance levels.Based on the infrared thermal imaging technology of UAV,this paper puts forward the establishment method of building three-dimensional thermal infrared model,and puts forward the rapid screening method for high heat loss of heating building and the quantitative evaluation method of overall heat loss of enclosure structure based on multi building three-dimensional thermal infrared model.The main research work is as follows:(1)This paper analyzes the inevitable relationship between the change of building surface temperature and the change of building envelope structure.Through the analysis of the heat transfer process of the enclosure structure,the influence laws of heat transfer coefficient,indoor and outdoor ambient temperature,wind speed,thermal bridge and other factors on the external surface temperature are revealed;Finally,through the analysis of the principle of infrared temperature measurement,the feasibility of judging the high heat loss of buildings caused by poor thermal performance of enclosure structure,excessive heating and thermal bridge based on infrared temperature measurement is demonstrated.(2)An experimental method of building infrared image acquisition using UAV equipped with infrared camera is proposed.Through literature research,the requirements of infrared image acquisition environment and image overlap for heat loss research are clarified;Through the field comparison experiment,the flight route,distance range and shooting angle range of the UAV during image acquisition are determined.(3)A method of building 3D thermal infrared model based on UAV infrared image is proposed.Firstly,based on the principle analysis of SFM 3D reconstruction,the reason of temperature loss in 3D model is revealed;Then,taking a building in Guangzhou as an example,this paper expounds in detail the method and process of retrieving the temperature value in the three-dimensional thermal infrared model,establishes the color three-dimensional point cloud model with temperature information,and verifies the accuracy of the temperature in the three-dimensional point cloud model with the help of the measured temperature of thermocouples;Finally,the three-dimensional infrared models of five test buildings in Shandong are established by using this modeling method.(4)A rapid screening method for high heat loss buildings in regional buildings is proposed.Firstly,the establishment method of three-dimensional infrared model of regional buildings is proposed,including unified monomer model working condition and unified temperature color mapping relationship;Then,taking Shandong Jining test project as an example,the three-dimensional thermal infrared model of regional buildings including five single buildings is established,and the screening method of high heat loss buildings is put forward;Finally,the accuracy of this method is verified by the measured energy consumption data.(5)Based on the method of "numerical simulation + regression analysis",the prediction model of "temperature baseline" on the outer surface of enclosure structure is established,and the evaluation method of local heat loss and the grading method of overall heat loss based on the overall facade of single building are proposed.Firstly,780 groups of exterior surface temperature data of building envelope under infrared image acquisition conditions are simulated by Flo VENT.By comparing and analyzing the prediction results of different regression analysis methods,the "temperature baseline" prediction model based on correlation vector machine(RVM)is finally determined;Then,the mask method for the overall image of each facade of the building envelope and the segmentation method of outer wall and outer window are proposed.Based on this,all the outer wall and outer window of each facade are obtained,and the local heat loss evaluation and overall heat loss rating of the whole envelope are carried out respectively;Finally,taking the temperature baseline as the comparison temperature,the quantitative evaluation method of local heat loss and the grading method of overall heat loss are proposed.Based on the combination of qualitative and quantitative principles,the detection and evaluation method for the heat loss of existing buildings in the northern heating area proposed in this paper covers the rapid general measurement for the regional scale at the meso level to the detailed detection for the building facade at the micro level,which provides a theoretical basis for the implementation of building energy-saving transformation in the northern heating area,It is of great significance to achieve energy conservation and emission reduction in the construction field and the "double carbon" goal at the national level. |
