Avaliação do impacto de subcoberturas no desempenho térmico de uma edificação residencial

Abstract

Single-family houses have large heat gain by its roofs, since the roof is the portion of the building most exposed to solar radiation along the day. In order to decrease this heat gain the use of roof underlayment is become common. The aim of this study is to verify the energy savings for air conditioning of a residential building in hot and humid climate (Belem), and to quantify the improvement in thermal comfort inside the same building for a mild climate (Porto Alegre and Sao Paulo), with the use of such insulating elements. Six roofing compositions were evaluated through computer simulation tool, Energy Plus. The following materials that compose the under layer were analyzed: asbestos cement roof , glass wool felt coated with aluminum foil on the upper surface and the lower layer coated with white laminate PVC, aluminum underlayment and wood ceilin. The parameters that characterize these materials are total thermal resistance and emissivity and the parameters used to describe the internal environment were electricity consumption for cooling and operative temperature according to adaptive model of thermal comfort analysis of ASHRAE Standard 55 - 2004. Contrary as expected, results for the city of Belem show that insulating materials minimize the lost of heat in the evening increasing the energy consumption for air conditioning around 4%(inverted glass wool felt and setpoit of 24 oC) and 27% (newly installed glass wool and setpoint of 26 oC). But the analysis of the seven hottest days of the year for the three cities shows that the use of underlayment of the roof reduces the internal peak of temperature between 5°C and 10 oC. Thus,