Portuguese thermal building legislation and stategies for the future

Abstract

Portugal must evaluate, according to the Energu Performance Building Directive, the national requirements for energy performance of new buildings until 2011, which can be an opportunity to devise a national stretegy that tightens the minimum energy performance requirements. The present study intends to analyze the changes that should be introduced in the Portuguese Regulation to achieve highl energy efficient buildings. The objective consists on evaluating the relevant improvement of thermal envelope performance such as walls, roofs and floors thermal insulation (maximum U-values), air tightness (ventilation strategies) and windows (minimum shading requirements), heating and cooling systems, as well as wider use of integrated renewable energy. The study considers apartments with different shape factors located in different climatic zones. The optimizing methodology makes use of a genetic algorthm for the estimulation of primary heating and cooling energy indexes through a simplfied calculation methodology established by Portuguese Regulation.