Climate parameters for thermal performance simulation according to the Brazilian standard NBR 15.575

Abstract

The Brazilian standard NBR 15.575 states that thermal performance evaluation of a building should be conducted by the relationship between outdoor temperature and indoor temperature conditions for summer and winter design days, which allows quantifying the compliance of the user requirements. Thus, this research aims to evaluate the thermal performance of a building considering different methods to determine the summer and winter days and different algorithms to calculate solar radiation (sky model). The methodology starts from a building located in bioclimatic zone 7, for which three sky model algorithms were tested, through computer simulation, for summer and winter design days. Without considering the sky clearness, the maximum and minimum indoor temperatures suffered slight variations when using different methods to obtain the design days, resulting in a Superior thermal performance level for the researched building. When considering the sky models, introducing sky clearness as an input parameter on the summer design day, the performance level was also Superior for the ASHRAEClearSky and ASHRAETau models, and intermediate for the Zhang Huang model, showing that the sky models can influence the performance classification. The ASHRAETau model provided, for the summer design day, underestimated indoor temperatures compared to other sky models, so its use is not recommended. Similar behavior was obtained for winter design day. The study subsidizes the construction of the design day for Brazilian cities not specified in the Brazilian standard, contributing to analyzing the existent gaps on normative parameters.