Natural ventilation of residential buildings in protuguese winter climatic conditions

In this paper, the current situation of Portuguese residential buildings in terms of ventilation systems ispresented. The indoor air renewal is, normally, obtained by providing fresh air exclusively by air leakage of doors and windows and their occasional opening and exhausting the air through ducts placed in kitchens and bathrooms. A recent revision of the Portuguese standard NP 1037-1, concerning natural ventilation of dwellings, is studied and its influence upon heating energy consumption and indoor temperatures is reported. In order to evaluate both thermal and ventilation impact of the adoption of NP 1037-1, a dynamic simulation was undertaken, using Trynsis 15 and Comis 3.1 software. Some results of this study concerning a residential building, located in different Portuguese winter climatic regions, are presented. The relative influence of both wind and thermal stack effect has been evaluated, the cooling effect of ventilation for unheated indoor environments has been quantified and the importance of parameters like the location of the dwelling in thebuilding, its orientation and the opening height have been analysed. Some ventilation devices were simulated, like self-regulated inlet grilles (trickle ventilators). Finally, other strategies of improving ventilation, keeping low heating energy consumption, have been considered, namely demand controlled ventilation.