Study On The Performances Of Heat Moisture And Air Permeation For The Wall Materials Of Composite Insulation Block

Energy saving for the wall of composite insulation block and indoor environment of building are significantly influenced by performances of heat and moisture as well as air permeance for the wall materials of composite insulation block. The lack of performances of heat and moisture as well as air permeance brings certain difficulty to analysis on the performances of heat and moisture as well as air permeance for them and further research must be taken. By the theoretical analysis and physical test methods, we focused on composite insulation block wall materials, and studied the performances of heat and moisture as well as air permeance for them, including two types of main materials as fly ash composite insulation block and coal gangue and shale composite insulation block, 3 types of backfill materials as rice husk slurry, expanded perlite slurry, expanded polystyrene board.A coupled heat and moisture as well as air transfer model of composite insulation block wall which is driven by air humidity rate and temperature is established. Parameters like heat and moisture as well as air permeance which are required in solution of model’s control equations are obtained.Moisture content of equilibrating in 6 saturated salt solution for five composite insulation block wall materials were tested and the isothermal sorption curves of these 5 materials were obtained respectively according to 3 types of fitted equation. And thermal conductivities of different moisture contents were measured, the relationship between coefficient of thermal conductivity and moisture content was fitted. Thermal conductivity of materials increase exponentially as the increase of the moisture content. The change of thermal conductivity should be considered in the research of thermal and moisture transfer performances of composite insulation block wall and the moisture-proof measures must be taken to ensure the good efficiency of energy-saving.Water vapor diffusion coefficient for 5 wall materials of composite insulation block was tested. Change law between water vapor diffusion coefficient and relative humidity was studied The relationships between water vapor diffusion coefficient and equilibrium relative humidity are established by fitting and the relationship between them can be described as power function. Water vapor diffusion coefficient can be deam as a constant when the equilibrium relative humidity is less and it obviously increases when the equilibrium relative humidity is larger than a certain value.Absorption coefficient and capillary saturation water content of 5 composite insulation block wall materials were studied by self-made instruments. And the relationships between the liquid water diffusion coefficient and moisture content were established. Liquid water diffusion coefficient increases with the increase of moisture content. Liquid water diffusion coefficients of the wall materials must be considered when studied on the heat and moisture as well as air permeance performance of the wall. Water vapor diffusion coefficient should be considered when the humidity is very high and liquid water diffusion coefficient should also be considered.The air permeability coefficients of five composite insulation block wall materials were tested by customized air permeability apparatus. The air permeability coefficients of different materials are different.