Dynamic thermal evaluation of a green roof system under warm weather conditions: Case of Tropical and Dry climates

Abstract

This study presents the thermal evaluation of a green roof (GR) under the climatic conditions of two typical warm climates in Mexico: dry arid (BWh) and humid tropical (Af). The thermal behavior of the analyzed system was assessed using a numerical code based on the finite volume method, which was effectively validated with experimental data, showing less than 6% difference in volumetric water content (VWC) and surface temperature on the substrate. The GR was evaluated over the warmest and coldest periods of the year; its performance was compared to that of a conventional concrete roof (RR). The results indicated that the GR system significantly reduces energy gains by up to 90 and 94% during the warmest period in the BWh and Af climates, respectively. For the Af climate, the VWC decreased by 18% during the warm period and by 4% in the cold period. For the BWh climate, there was a reduction of 17.1% in the cold period and 60% in the warm period. This finding highlights the need for substrate irrigation to maintain evaporation energy dissipation in the arid climate during the summer.