Study On Heat And Moisture Coupling Transfer And Freezing And Thawing Of Typical Walls In Severe Cold Region

The composite wall and its thermal insulation materials are composed of porous materials.Under the changing indoor and outdoor thermal and humid environment conditions,the research on the dynamic heat-moisture coupling transfer,freeze-thaw,wet accumulation and dehumidification problems inside the building envelope is very complicated and important.Based on Delphin software,this paper mainly studies the dynamic heat-moisture coupling law and characteristics of two typical composite walls in the severe cold regions of northern China.Firstly,the numerical model is validated by using the experimental data of the literature.On this basis,the wet stability time and its influencing factors,internal water content distribution,ice content distribution,average thermal conductivity and average heat transfer coefficient within typical composite walls were studied under unsteady environmental conditions.The one-dimensional model is used to calculate the dynamic heat-moisture coupling of reinforced concrete shear wall in the representative cities of Harbin,Nenjiang and Mohe.Obtain the internal water content distribution,ice content distribution of the reinforced concrete shear wall and the change of internal surface temperature under different initial relative humidity of materials,different building completion time,different wall orientations,different climatic conditions.The time required for the reinforced concrete shear wall to reach a wet stable state and the water content and thermal conductivity value of the wall when it reaches a wet stable state are obtained,and then comparative analysis is carried out.The two-dimensional model is used to simulate the dynamic heat-moisture coupling transfer of concrete hollow block wall in Harbin,and the internal water content and ice content of concrete hollow block wall are analyzed.The time required for the concrete hollow block wall to reach a wet stable state and the water content when the wall reaches a wet stable state are obtained.By studying the variation law of the average wall heat transfer coefficient of the typical wall with the initial relative humidity of the material,the completion time of the building,the thickness of the EPS board,the orientation of the wall,and the climatic conditions.The paper analyzes the factors affecting the average heat transfer coefficient of composite wall.Provide theoretical guidance and data support for the calculation and analysis of building heating energy consumption.