Investigations

DECODING THE IMPLUVIUM COURTYARD: Southwest / Tropical Savanna 

CLIMATE ZONE: Wet-and-Dry / High Humidity 

SUBJECT TYPOLOGY: Yoruba Afin (Palace) & Domestic Courtyards 

FOCUS: Passive Cooling, The Stack Effect, and Hydraulic Harvesting

01. THE INVESTIGATION 

In the humid tropical savanna of southwestern Nigeria, standard modern concrete construction creates lethal indoor heat indexes, relying heavily on grid-tied HVAC systems that fail during frequent power outages. Case File 002 investigates the indigenous alternative: the traditional impluvium courtyard structure. Historically utilized in Yoruba Afin (palace) architecture, the impluvium is a sunken central courtyard fed by inward-sloping roofs. While historically cataloged merely as a "water collection" system, A|WA hypothesizes that it functions as a sophisticated passive cooling machine.

02. THE HYPOTHESIS: THERMODYNAMIC PERFORMANCE 

We propose that the impluvium geometry generates a localized "Stack Effect" (buoyancy-driven ventilation). As the sun heats the roof material, the inward-sloping geometry funnels rainwater into the central basin. The evaporation of this trapped water creates a high-humidity, low-temperature micro-climate in the center of the structure. As hot air naturally rises and escapes through the roof aperture, it pulls cooler, shaded air from the surrounding rooms into the courtyard. We hypothesize that this continuous thermodynamic loop keeps the interior of the structure 5°C to 8°C cooler than the

exterior ambient temperature, entirely off-grid.

03. FORENSIC METHODOLOGY 

To move this indigenous technology from "historical artifact" to "empirical data," A|WA will deploy the Mobile-Field Studio (DRU-01) to capture the thermodynamic metrics of surviving impluvium structures in the Ife/Lagos corridor.

• Airflow Mapping (CFD): We will utilize localized anemometers and Computational Fluid Dynamics (CFD) modeling to map the exact velocity and trajectory of air moving from the peripheral rooms through the central roof aperture.

• Environmental Logging: Deployment of HOBO UX100 series data loggers over 72-hour cycles to record precise Temperature and Relative Humidity (RH) differentials between the impluvium center, the interior rooms, and the exterior environment.

• Spatial Documentation: Sub-millimeter LiDAR scanning to archive the precise roof-pitch angles and basin dimensions required to optimize the Stack Effect.

04. APPLICATION & FUTURE HORIZON 

The objective of Case File 002 is not preservation, but translation. By extracting the exact geometric and thermal ratios that make the Yoruba impluvium successful, we can digitally translate these principles into modern, high-density housing prototypes. The data collected here will directly inform the design protocols for passive ventilation in off-grid tropical environments.