Mapeamento de coberturas e estimativa de irradiação solar

Abstract

This study aimed to evaluate a methodology for mapping and estimating solar radiation on the roofs of six buildings at the Universidade Federal da Fronteira Sul (UFFS) – Campus Cerro Largo. The coverages were grouped into three sample areas and the data collected, with the aid of an RPA (Remotely Piloted Aircraft), generated a Digital Surface Model (MDS). The average slope of area one was 14.75°, while areas two and three were 9.83° and 7.55°, respectively. The sloping roofs towards the north and south occupy a larger area in the roofs, with 30% each, the other orientations vary between 5% and 8%. From the MDS, the total solar irradiance was estimated, using the r.sun tool, developed by GrassGis, for two days of the year (winter and summer solstice in the southern hemisphere). For the coverage of area one, in the winter solstice the irradiation estimate varied between 336 and 6,958 Wh/m².day (average = 3,395 Wh/m².day). For the summer, the variation was between 575 and 9,466 Wh/m².day, with an average of 8,607 Wh/m².day. The solar irradiation data for the coverage of area two, obtained variation between 337 and 6,616 Wh/m².day in the winter solstice and 577 and 9,464 Wh/m².day in the summer solstice, with averages of 3,617 and 8,884 Wh/m². .day, respectively. For area three, on the other hand, the values varied between 338 and 6,956 Wh/m².day in the winter solstice and 578 and 9,465 Wh/m².day in the summer solstice, their averages were 3,595 and 9,108 Wh/m². day, respectively. The estimated total irradiation for the winter solstice in areas one, two and three was 5,639, 4,467 and 13,427 kWh.day, respectively. For the summer solstice, values of 14,296, 10,972 and 34,018 kWh.day were verified. The results obtained were compared with data from the INMET meteorological station network and the IRIOGRAN38 automatic meteorological station located on the university campus. There was a difference in the estimated values at the winter solstice between 38% and 47% for the mean data from the A810 meteorological station and 63%, 73% at the 83907 station and between 44% and 53% at the IRIGRAN38 station. For the summer solstice the differences were between 48% and 57% at station A810, 31% and 39% at station 83907 and 48% and 56% at station IRIGRAN38. The estimation of solar irradiation carried out through the r.sun tool present in the QGIS software proved to be efficient for modeling solar irradiation on clear sky days, if the intention of the project is to plan the installation of solar panels, one must add to the model a index that considers the cloudiness of the region.