湿热气候条件下砌体结构材料热湿物性参数对热工计算的影响

The influence of thermal and moisture property parameters of masonry structure materials on thermal calculation in hot and humid climate

针对湿热气候地区高湿度对砌体结构隔热的不利影响,利用计算机软件模拟四种不同砌体结构材料热湿物性参数:导热系数、蒸汽渗透系数和液态水扩散系数在动态热湿环境下的变化,从而分析热湿物性参数变化对建筑围护结构热工计算的影响程度.结果表明:在湿热气候条件下,湿传递对热工计算结果的影响较大,传热量最多增加30%;导热系数变化对传热量影响的幅度在5%~10%;蒸汽渗透系数变化对传热量影响在3%以下;液态水渗透系数受室外计算条件影响,非雨天时,其值变化对传热量计算不大,雨天时,其值变化对传热量影响在30%以上.因此,在湿热气候条件下,进行砌体结构围护结构的热工计算时,导热系数应视为材料含湿量的函数计算,蒸汽渗透系数可按常数计算,液态水扩散系数需要考虑雨天和非雨天分别进行计算.

Aiming at the adverse effect of high humidity on the thermal insulation of the masonry structure in hot and humid climates,this paper uses the computer software to simulate the thermal and moisture physical parameters of four different masonry structural materials:thermal conductivity,coefficient of vapor permeability and liquid diffusivity under dynamic thermal and humid environment changes.Thereby to analyze the influence degree of the change of thermal and moisture physical property parameters on the thermal calculation of the building envelope.The results show that in hot and humid climate conditions,moisture transfer has a greater impact on the thermal calculation results,which will increase the heat transfer by up to 30%.The influence of thermal conductivity change on heat transfer is 5%~10%.The change of vapor permeability coefficient has less than 3%influence on heat transfer.The liquid water permeability coefficient is affected by the outdoor calculation conditions.In non-rainy days,its value change has little effect on the calculation of heat transfer.In rainy days,its value change affects the heat transfer by more than 30%.Therefore,under hot and humid climate conditions,when performing thermal calculations of masonry structure,the thermal conductivity should be calculated as a function of moisture content,and the coefficient of vapor permeability can be calculated as constants.And the liquid water diffusion coefficient needs to be calculated separately considering rainy days and non-rainy days.