Roof thermal performance analysis to passive cooling of dwellings in warm humid climate
passive cooling, thermal performance, dwelling roof, dynamic computer simulation
This work presents an analysis of passive cooling potential of dwellings through the roof, in a low latitude warm and humid climate. Despite high solar radiation on the horizontal plane in this climate, conventional roofs of red ceramic tiling and plaster ceiling or concrete slabs have low thermal performance, which can be improved by passive cooling techniques. Therefore, the work aims to determine roof strategies that provide thermal comfort. A reference model of a row house in the climate of Fortaleza-CE was used in dynamic computer simulations with the EnergyPlus algorithm through the Grasshopper/Ladybug platform. It was analyzed flat roof strategies, of green or cool roof, and five diferent strategies of tiled roofs: change of tiles with external surface characteristics of high solar reflectivity and thermal emittance; thermal insulation; ventilated attic; ventilation through the roof with air outlets on tilings and ceiling; and high ceiling height. Based on the criteria of thermal comfort or discomfort occurrence of adaptative models (ASHRAE, 2017; DE DEAR; BRAGER, 2002), the green or cool insulated flat roof or the combination of at least two of the tiled roof strategies, with the exception of high ceiling height, reduce the annual period in heat to zero and requiring air movement on people in few hours by the capacity of lowering indoor temperatures.