Comparative analysis of user comfort and thermal performance of six types of vernacular dwellings as the first step towards climate resilient, sustainable and bioclimatic architecture in western sub-Saharan Africa

Abstract

The purpose of this study is to assess thermal comfort conditions in vernacular dwellings in western sub-Saharan Africa. The paper identifies six vernacular and low-tech building typologies specific for selected countries. Comparative analysis of user comfort and thermal performance of case studies, representative for each typology was carried out, as the first step towards climate resilient, sustainable and bioclimatic architecture in the region of the investigation. The measurements of temperature, relative humidity, indoor air quality and daylighting as well as the user satisfaction survey were performed in February 2019 and repeated in August 2019. It was determined that during the hot and dry season, the indoor temperatures of 26–30 °C were achieved in traditional dwellings (Typologies I-IV) and accepted by 60–70% of inhabitants, while in ‘modern houses’ (Typology VL2 and VI) the level of user thermal comfort was significantly lower (only 20% felt comfortable). During the colder wet season 90% of users felt comfortable in vernacular dwellings and only 50% in ‘modern houses’. High levels of CO2 concentrations were detected in dwellings with tight envelopes (1800–1900 ppm) due to the lack of adequate ventilation. In pursue of solution various air exchange rates were examined to check how they comply with the user thermal comfort perception. It was found that the optimal ventilation should provide the air exchange rate of 0.5 VR/h which allows to fulfil minimal demands of ISO and ASHRAE standards. The study established the baselines for sustainable, bioclimatic, affordable housing model for western sub-Saharan Africa.