Effect of Solar Radiation on Hygrothermal Performance of Multi-layer Wall of South China

A dynamic model was established for evaluating the hygrothermal performance of typical plaster-brick-cement mortar wall in south China which used air humidity ratio and temperature as the driving potentials. In the main model, the hygrothermal performance of the multi-player wall under the effect of direct solar radiation by decomposing the total solar radiation into direct solar irradiation in different directions, while in the sub-model the solar radiation was neglected. The solution for the governing equations was obtained numerically by implementing the finite-difference scheme. The comparison of the computational simulation results with the experimental results indicated: Temperature at exterior layer of the wall was obviously affected by the change of direct solar irradiance and because of the rise of temperature, the relative humidity of the wall also increases. In most area of south China in summer the solar radiation may strong and cause the accumulation of moisture inside the wall which has adverse effect on building structure.