Towards a Theory of Bioclimatic Urbanism for Sub-Saharan African Tropical Cities: Methodology and Application

Bioclimatic design at the scale of urban form, rather than the individual building, offers the most substantial opportunity for reducing heat stress, improving outdoor comfort, and reducing cooling energy demand in sub-Saharan African tropical cities, yet no coherent theoretical framework for bioclimatic urbanism calibrated to the specific climate conditions and urban morphology patterns of this region has been developed. This dissertation develops an original theory of bioclimatic urbanism for sub-Saharan African tropical cities, constructing both a theoretical framework and a validated design methodology through research conducted in Lagos, Ibadan, and Aba. The theoretical framework integrates urban heat island theory, computational fluid dynamics modelling of urban airflow, outdoor thermal comfort physiology adapted to West African climate and skin pigmentation variables, and morphological analysis of existing urban fabric to produce a multi-scale theory of bioclimatic urban design operating at the urban precinct, street canyon, and open space scales. An original street morphology-to-outdoor comfort transfer function is developed from field measurement data and CFD validation, enabling rapid performance prediction for alternative urban form configurations without full simulation. The design methodology derived from the theoretical framework specifies bioclimatic street orientation corridors, solar access-shading design envelopes for buildings, tree placement strategies for combined shade and wind channelling effects, and surface material albedo requirements. Application of the methodology to three urban intensification projects in the case study cities demonstrates measurable improvement in predicted outdoor comfort conditions compared to conventional design alternatives. The dissertation contributes original theory, a validated analytical methodology, and demonstrated design applications. Keywords: bioclimatic urbanism, sub-Saharan Africa, outdoor thermal comfort, urban heat island, tropical cities.