ESTIMATIVA DA DISPONIBILIDADE DE LUZ NATURAL E DO PADRÃO DE CÉU NA REGIÃO AMAZÔNICA

MACAPÁ-AP, LAT. 0°.

Abstract

Despite the importance of the quantification of the available natural light to provide basis to buildings and cities design, that kind of data has never been measured for the city of Macapá and it is the key to support the elaboration of window’s systems that take advantage of the natural light, improving quality and energy efficiency to the environments on both the building scale and the urban scale, ensuring that external natural light reaches the façades of buildings.In this sense, the objective of this article is to characterize the behavior of Macapá’s sky, providing an estimate of light availability and sky patterns, data that may support future studies on natural light in the capital of the state of Amapá. In order to achieve this, bibliographic research on the subject was carried out, collecting data on cloudiness, precipitation and insolation in the National Institute of Meteorology (INMET) database. The data on incident solar radiation for horizontal surface were obtained in “Luz do Sol” program and measurements were made of the levels of illuminance for horizontal plane, together with measurements of sky patterns. All data were collected at solstices and equinoxes, or near that dates, from June 2017 to March 2019, at a time interval from 9:00 am to 6:00 p.m., with hourly records organized in the form of graphics and histograms to characterize the frequency of occurrence. The results for the period shows that Macapá is a city with extreme variations of rainfall regimes (33.7mm to 415mm), cloudiness (6.0 to 9.6) resulting in variations of solar radiation of 3,698Wh / m² and 8,153 Wh / m² and sunshine between 83.10 hours and 282.3 hours, in which the maximum illuminance always appears in September and the minimum illuminance appears in sometimes March and sometimes in December. On measured illuminances, daily averages ranged from 73,412llux (in September) to 11,888 lux (in December), but the levels reached 121,565lux in September 2017. The characteristic sky pattern of the city is the overcast sky occurring at 58, 67% of the measured hours and the most frequent available light levels are those between 10,000 and 20,000lux, occurring in 21.79% of the measured hours.