Modelling of Heat Transfer in Laterite-Stabilised Walls for Energy-Efficient Building Design in Nigeria

The building sector accounts for a substantial fraction of energy consumption in Nigerian urban centres, driven largely by space cooling loads in poorly insulated structures. Laterite-stabilised walls, combining the high thermal mass of laterite with the structural improvement of cement stabilisation, offer potential for passively reducing indoor temperature peaks. This study develops and validates a transient heat transfer model for laterite-cement stabilised walls under Nigerian tropical climate conditions. Wall samples of 150, 200, and 250 mm thickness are fabricated with laterite sourced from Ogun State at cement contents of 4, 6, and 8 percent. Thermal conductivity, specific heat capacity, and thermal diffusivity are measured by the transient plane source method. A finite difference numerical model of one-dimensional transient heat conduction is developed in MATLAB and validated against thermocouple measurements in a controlled outdoor test chamber over 30 days. The model is then applied to simulate annual thermal performance for typical house wall configurations in Lagos, Abuja, and Kano. Results indicate that 250 mm laterite-cement walls reduce peak indoor temperature by 4.2 to 6.8 degrees Celsius relative to standard sandcrete block construction. Decrement factor and time lag are quantified for each wall thickness and cement content combination. The study provides design data for energy-efficient affordable housing under Nigeria's National Housing Fund programme. Keywords: heat transfer, laterite wall, thermal mass, building energy, Nigeria