Discussão dos requisitos e dos limites das propriedades térmicas para garantia de conforto térmico segundo as normas brasileiras

Abstract

The usual nether thermal performance of residential buildings occasioned the increase of energy consumption due to the use of artificial conditioning to obtain thermal comfort of the users. In order to regulate the minimum thermal performance of a building, national performance standards were established. Currently, two standards that approach the thermal performance of residential buildings are ruling in Brazil: NBR 15.220 (2005) and NBR 15.575 (2013). Studies developed indicate inconsistencies in these norms, besides there is a dissociation between the recommendations and the guarantee of thermal comfort of the user. Thus, the objective of this article is to propose an integration of the thermal performance requirements of NBR 15.220 and NBR 15.575, in addition to new requirements that can guarantee the thermal comfort conditions of users. The analyzes were carried out by means of computational simulation for a multifamily residential building in three cities of each bioclimatic zone. To evaluate the impact of thermal properties the envelope was altered in 6 types of walls, 4 types of coverings and 4 conditions of openings. The results indicated that the main properties for the thermal performance were the thermal capacity of the walls, the thermal transmittance of the roof and the absorbance of the envelope, besides the control of the thermal gain by the openings in hot climates. It is suggested that limit values for the thermal variables, also the need for ventilation.