Conjugate conduction-natural convection heat transfer in a hollow building block

Conjugate heat transfer across a hollow block is investigated numerically. Conduction heat transfer in the block material and natural convection in the cavity are considered. Results show that increasing the number of cavities while keeping the block width constant decreases the heat loss (increases the R-value) significantly. A maximum number of six cavities can fit the building block without compromising the strength. With this number of cavities, no insulation would be needed to fill the cavities as a result of the reduced effect of natural convection. This study may provide guidelines for engineers toward better design and selection of building materials for higher thermal resistance.