Conjugate Heat Transfer Analysis in a Composite Building Wall: Effect of Double Plaster-Brick-Glass Wool

Abstract

AbstractThe goal of this analysis is to explore heat transmission by three modes of heat transfer in a double plaster-brick-glass wool wall with a layer of air between them. The governing equations were solved using SIMPLE scheme of finite volume method (FVM). Effects of solar radiation (up to 1000 W/m2), variation of glass wool thickness (2–5 cm), and variation of thermal emissivity (0.1–0.9) on the heat transfer through the composite wall were examined. It was found that the surface radiation has contributed more than 60%, while the natural convection and conduction were not exceeding 23.08% and 3.39%, respectively, in the heat transfer process. The effect of variation in glass wool thickness was insignificant on the coefficient of overall heat transfer, but the inside wall temperature reduced by 0.25%. The mean temperature of the inner wall surface was reduced to 10.8%. The low emissivity structure surfaces (Ɛ < 0.3) offered strong thermal resistance in heat transfer. The results suggested that a 2 cm layer of glass wool insulation and low emissivity surface can significantly reduce the building energy usage.KeywordsAir layerDouble plaster-brick-glass wool wallSolar radiationComposite wallHeat transfer