Comparison of passive cooling techniques in reducing overheating of clay-straw building in semi-arid climate

Abstract

Residential and tertiary buildings constitute, in Morocco, the largest energy-intensive sector, accounting for 51% of its total electricity consumption. Decreasing the growing building energy demand presents, therefore, one of the key factors for achieving energy autarky and substantially reducing the use of imported fossil fuels for electricity generation. In this paper, we studied several passive cooling techniques integrated into a numerical model of a clay-straw building in semi-arid climate, aiming simultaneously to reduce the energy demand for cooling and improve the building thermal comfort by reducing overheating hours. The results show that automated movable shading is the most effective solution. Moreover, the clay-straw building that integrates the passive cooling techniques shows a reduction of the indoor temperature by 5 °C in the warmest day of summer in comparison to a reference building representative of actual Moroccan villas made of concrete and lacking passive cooling techniques. Furthermore, it reduces the total energy demand by 65% while decreasing the number of discomfort hours resulting from overheating by 25%. In addition, the passive cooling techniques showed quite the same effectiveness in summer conditions whether used in a concrete or a clay-straw building. Eventually, we suggest that the Moroccan thermal code should encourage the use of passive cooling techniques, especially in hot semi-arid climate.