Modeling Solar Energy Transfer through Roof Material in Africa Sub-Saharan Regions

Abstract

As a result of the global warming, the atmospheric temperature in sub-Saharan regions of Africa may drastically increase, thus worsening the poor living conditions already experienced by people in those regions. Roof’s thermal insulation capacity may play key role in reducing indoor thermal comfort cost. In the present study, effort is put to model heat transfer through roofs in south Saharan regions. Validation of the model was achieved using the slightly sloppy galvanized aluminum-iron sheet roof. Atmospheric data were hourly measured during April and June in Ouagadougou, Burkina Faso. Solar energy values increase from 24.50±0.50 W/m2 in the morning to a maximum of 900.1±0.8 W/m2 in the early afternoon. Ambient temperature follows the same trend as solar radiation with a maximum at 40.0±0.2°C. Wind speed varies from 0.5 to 4.0±0.1 m/s. The measured roof inner wall temperatures agreed excellently with the developed model with a Nash-Sutcliffe Coefficient of Efficiency of 0.988. Energy flux entering the room through the roof varies from 63.1±0.3 W/m2 earlier in the morning to a maximum of 115.3±0.5 W/m2 in the earlier afternoon. These results shall help to better design human habitat under changing climate conditions in the sub-Saharan regions.