Análise do desempenho de aberturas zenitais em regiões tropicais através de modelagem paramétrica

Abstract

The zenith openings of a building are responsible for allowing the entry of daylight inside the ambient, as well as the admission of solar radiation. Which can bring unwanted thermal gains, especially in locations with a tropical climate. For the indoor enviroment to be comfortable, it is important that there is a balance between the amount of daylight, and the levels of solar radiation that affect the interior of the environment. This balance can be sought through the proper dimensioning of this environment, along with the dimensions of the zenith openings. For this reason, the present study proposes to evaluate the autonomy of the zenith daylighting as well as to quantify the indoor direct radiation incidence in a parametric geometric model, developed buildings with 4 skylights types: Skylight, Sawtooth, Dome and Lantern. The illuminance evaluation took place in an indoor architectural environment with dimension values obtained from the literature. The dimensional parameters of the building and the zenith daylighting typologies can be changed by the parametric models in search of an optimal solution for maximum use of daylighting, considering the lowest rate of solar radiation accumulated inside the studied environments. This study was developed based on the hot and humid tropical climate of the city of João Pessoa - PB. The research was developed with the aid of the Rhinoceros 3D + Grasshopper modeling software together with the plug-ins for dynamic computer simulations related to daylight and accumulated incident solar radiation, Ladybug and Honeybee. The performance of daylight autonomy was analyzed through Daylight Autonomy metrics (DA 300) and Useful Daylight Illuminances intervals (UDI 150-2000 lux), the accumulated incident solar radiation was quantified through Radiance, in kWh/m². For the simulations, meshes with photosensitive sensors were created, equidistant at 0.50 m each sensor, the meshes with photosensors were allocated on all internal walls and also on the floor. The reflectance indices of the materials assigned to the ceiling, walls and floor, as well as the refractive indices of the glasses used were based on the Inmetro Normative Instruction for the Energy Efficiency Classification of Commercial, Service and Public Buildings (INI-C). The analyzes were carried out over a period of one year, based on the luminous behavior of the models between 08:00 am and 4:00 pm. During the computer simulation process, 66716 possible dimensional combinations of the four studied typologies were tested. The study included analyzes for North and East facade orientation, as well as tests with photosensitive sensor meshes on the walls and floor were simulated separately. The exploration of the solution space of the parametric models generated very clear results of the relationship between the autonomy of daytime lighting and the incidence of direct solar radiation inside the geometric models, showing that the size of the zenith openings and other room dimensions can generate direct influences in the results of daylight autonomy and incidence of direct solar radiation inside the environment. It was observed that the orthogonal positioning in relation to the ground of the openings in the Sawtooth and Lantern typologies generated more uniform results during the convergence to the best parametric configuration. The Skylight presented the smallest openings among all typologies analyzed, due to the positioning of its zenith openings. The Dome presented greater similarity between the configurations of the best result, in each scenario proposed for the study. Finally, Lantern presented the largest openings, as well as generating the best global results among all the typologies studied.