Study of the influence of roof insulation involving local materials on cooling loads of houses built of clay and straw

This paper presents an investigation of the influence of local insulated roofing materials used in Burkina Faso on air conditioning loads of typical individual houses located in dry tropical climates. The walls are made of a composite clay–straw mixture whereas the insulated materials are made of red wood, white wood, and two assembled insulated panels. The thermophysical properties of the insulating materials as well as the clay–straw composite have been studied, utilizing an experimental apparatus based on the hot plate method. The values of the thermophysical properties obtained are in the same range as those published in the literature. Afterward, the house has been modeled using TRNSYS together with the climatic data of Ouagadougou. This simulation shows that the clay–straw mixture reduces the air conditioning load by about 8% compared to clay walled houses. As for the roof, the study indicates the influence of the insulated materials on the air conditioning load. Hence, a 1.5 cm thick insulator made of red wood induces a saving of energy about 6.2% and 12.1% for an insulation panel made of natural fiber and a lime–cement mixture on the air conditioning load.

► Small amount of straw (3%) in a clay wall largely improves the insulation properties.
► Panel made of natural fibers of Burkina Faso and lime–cement is a good insulator.
► These insulation materials can reduce the energy consumption in a house by 18.4%.