Thermal Mass and Passive Cooling: An Original Computational Framework for Earth Architecture Optimisation in Nigerian Climate Zones

Earth architecture offers a climatically responsive, resource-efficient, and culturally grounded construction approach for Nigerian conditions, but its application is impeded by the absence of validated computational tools calibrated to Nigerian climate variability, earth material properties measured from locally available soils, and the specific building typologies characteristic of Nigerian construction contexts. This dissertation develops an original computational framework for optimising thermal mass and passive cooling performance in earth architecture across Nigerian climate zones, making contributions to building physics theory, computational simulation methodology, and earth architecture design practice. The theoretical contribution develops an enhanced thermal mass performance model that explicitly accounts for the complex moisture dynamics of unstabilised and partially stabilised earth walls under humid tropical and semi-arid conditions, which produces material thermal property variations overlooked in existing steady-state thermal mass models. Laboratory characterisation of thirty-two Nigerian earth material samples from six geopolitical zones provides the empirical material property database for the model, measuring thermal conductivity, specific heat capacity, density, moisture adsorption isotherms, and hygrothermal coupling coefficients. The computational framework integrates the enhanced material model with EnergyPlus dynamic thermal simulation, generating a validated coupled heat-and-moisture transfer simulation tool for Nigerian earth buildings. The tool is validated against three months of monitored building performance data from earth buildings in Sokoto, Plateau, and Kwara states. Application of the framework generates optimised design parameters for earth wall thickness, stabilisation level, roof overhang depth, and opening configuration for each of Nigeria's five main climate zones. Original design guidance documents derived from the framework are presented as practical outputs. Keywords: thermal mass, earth architecture, passive cooling, computational framework, Nigerian climate zones.