Desempenho térmico da cobertura de habitação do tipo fita em clima quente e úmido e meio urbano adensado

Abstract

This work presents an evaluation of passive cooling potential of row houses through the roof in dense urban environment and warm and humid climate. Despite high solar radiation on roofs in this climate, its cooling capacity can be assessed to improve the low thermal performance of conventional roofs of red ceramic tiling and plaster ceiling, recurrent in self-built or social housing in Brazil. Row houses have the roof as the largest part of its envelope exposed to exterior climate, and the natural ventilation through wind is impaired due to its elongated plan, mainly when in a dense urban environment. In the case of these restrictions, this research aims to optimize the roof thermal performance, by means of recurrent characteristics in vernacular or contemporary architecture. A reference model of a row house in the climate of Fortaleza-CE was used in thermal simulations of the software EnergyPlus in order to quantify the influence of five different characteristics: type of tiles; thermal insulation; presence of attic and its ventilation; ventilation through the roof by chimney effect and 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 research showed that the combination of strategies of low solar absorptance, with bright colors or metallic surface, low thermal transmittance, with presence of attic or insulated layer, and ventilation through the roof, can reduce to 0% the heat discomfort occurrence throughout the year, due to low heat flows and low internal air and superficial temperatures. The attic ventilation benefited the performance in the cases without ventilation through the roof, and with high absorptance or high transmittance. The colonial ceramic tiling allows air changes of the air chamber formed by its overlaid tiles, and has superior performance compared to roman tiles when there is ventilation through the roof and the tiles have high thermal absorptance and transmittance. The high ceiling height didn’t influence significantly the roof thermal performance.