O impacto dos parâmetros urbanísticos no desempenho da ventilação natural urbana: o controle da ocupação do solo a partir dos recuos progressivos

Abstract

Regions of hot humid climate, such as Maceió-AL, present small daily fluctuations of air temperature and high humidity. For best thermal performance, buildings should avoid heat gain and dissipate heat produced internally as well as the heat absorbed by the envelope. Natural ventilation plays a fundamental role in this heat dissipation. The general objective of this doctoral research is to investigate the effect of the porosity of the urban mesh from different progressive recoils, associated with other urbanistic parameters and its impact on natural ventilation, for the context of Maceió-AL. We sought to investigate seven adaptations of the calculation formula of progressive recoils existing in the urban legislation of Maceió. For this purpose, the performance of natural ventilation was analyzed comparatively in different scenarios created according to parameters established by the legislation, as well as in scenarios proposed based on the maximum utilization of the land use coefficient and avoiding the control of the height of the site template. For this, simulations of computational models were performed in CFD environment, with the program Phoenics 2018 v1.0. Thirty-two construction models were simulated, with normal wind incidence angle (90 °) or oblique (135 °), representing the two prevailing wind incidence directions of the region. In addition, the existence or not of the pilotis in the architectural party was considered. Statistical analyzes were also developed to identify the most impacting variables for natural ventilation. The results indicated that the modeled urban scenarios were quite sensitive to wind orientation, and the oblique incidence (135 °) to the built mesh promoted the maximum wind speeds. The sectioned effect of the pilotis was conditioned to where the measuring points were located, as the presence of its built-up area affected the wind speed results. Finally, it was found that the increased porosity of the urban mesh from the dimensioning of the distances resulted in significant improvements in natural ventilation, especially at pedestrian level. And its relationship with higher building heights also showed better performance, especially in the most distant regions of the ground.