A porta de entrada para a iluminação natural: uma análise do desempenho luminoso da porta na arquitetura residencial dos trópicos

Abstract

For long periods in history, some civilisations used the door as the only opening in their buildings. As well as necessarily functioning as a passageway, it was through the door that many of the buildings' internal environments were lit. As the history of architecture evolved, this function of illuminating spaces was taken over by courtyards and atriums and, later, by the window, which is now the main architectural device used in studies that assess the performance of natural light inside environments. Although the focus is on windows, the principles used in these studies can be applied to the entrance door, which can also function as a source of natural light for internal spaces. With this in mind, the general aim of this dissertation is to evaluate the use of the entrance door in utilising natural light in a residential environment in the city of Maceió/AL. As specific objectives, the work aims to assess whether the use of the entrance door to provide natural light inside the room meets the lighting comfort conditions established in current standards, and to analyse the influence of the different opening configurations of this element on the availability and distribution of natural light inside the room. The study was carried out for a hypothetical environment, using the computer simulation method. TropLux software was used for the processing, in order to comparatively analyse the influence of a set of variables on the availability of natural light inside the proposed environment. The results show that, for most scenarios, the entrance door meets the requirements established by NBR 15575-1 and the RTQ-R. External elements, such as eaves and obstructing buildings, can attenuate illuminance levels, contributing to a better distribution of natural light in the internal environment and avoiding situations of potential luminous discomfort. Wider doors, despite being able to maintain the minimum illuminance of 120 lx in more than 70 per cent of the area during more than 70 per cent of the daytime hours, can compromise visual comfort conditions due to the excessive incidence of the sun's rays, contributing to the occurrence of unwanted contrasts and glare. Centralised doors provide brighter environments with a better distribution of natural light. Opening angles of less than 45° can significantly affect the overall average illuminances, negatively impacting the autonomy of natural light in the space. Dutch doors, on the other hand, show a peculiar behaviour in terms of lighting performance, due to one of their openings being situated below the reference plane for measuring illuminances. The shape, layout and distribution pattern of the glazed surfaces also have a significant influence on luminous performance, revealing the importance of this multifunctional piece in the design of spaces.