Evaluation of passive strategies, natural ventilation and shading systems, to reduce overheating risk in a passive house tower in the north of Spain during the warm season

Abstract

During the last decade in the European Union, some targets have been set to reduce energy consumption in buildings, promoting the construction of nearly Zero Energy Buildings and under certificates as Passivhaus. Different regulations define indoor comfort, also Passivhaus standards, considered in this study. Previous studies research the risk of overheating in these buildings, particularly during hot seasons, recommending multiple strategies that are described in this project. This study aims to detect the best natural ventilation and shading strategies to mitigate overheating issues during the hot period in a Passivhaus certified residential tower in Bilbao. The study will be carried out by dynamic simulations. It has been analysed different factors in order to quantify their direct impact on the indoor temperature, proving that overheating can occur, especially during the hot season. The research will conclude that corner-oriented and crossed-oriented flats work better than the single-oriented for natural ventilation, producing more renovations per hour. Shading systems work better when located outside and are mobile. When combining the best previous strategies, the temperature achieves Passivhaus limitations, but high airspeed rates occur, preventing users’ comfort. To achieve Passivhaus limitations is necessary to regulate different opening strategies to avoid high airflow rates and combine different passive strategies. • Overheat occurs on low energy consumption residential buildings in the warm season. • Internal gains are determinant of the design phase in this typology. • Natural ventilation or shading systems can reduce overheating risk. • Combining different passive solutions is more successful in mitigating overheating. • Strategies efficacy to mitigate overheating are simulated in Design Builder.