Thermal Performance of Composite Wall Systems Made from Hollow Concrete Blocks, Common Insulation Materials and Local Timber Finishes in Benin City, Edo State, Nigeria

Abstract

Building energy demand in hot tropical regions is strongly influenced by heat gains through walls and roofs, which increase indoor temperatures and drive the use of mechanical cooling. Therefore, the objective of this paper was to evaluate the thermal performance of composite wall systems made from hollow concrete blocks (dense and medium-density), common insulation materials (fiberglass, rock wool and expanded polystyrene foam) and local timber finishes (Agba wood and mahogany) in Benin City, Edo State, Nigeria using appropriate standard methods. Results obtained show that across all solid-insulation cases, expanded polystyrene produced the lowest heat flux and U-value, while replacing the dense block with a medium-density block further reduced heat flux due to the lower thermal conductivity. The best-performing solid configuration achieved analytical heat flux of 8.82 W/m² (U = 0.88 W/m²K) and ANSYS heat flux of 11.75 W/m² (U = 1.18 W/m²K). Some configurations showed notable model-simulation mismatch, highlighting the need to treat coupled convection and radiation within cavities rather than approximating air as a purely conductive layer. The results provide practical guidance for selecting wall-layer combinations that reduce heat gains and improve thermal comfort in tropical building design.