Design & placement of airing ducts in a passive house, driven by natural forces

A passive house in Norra Djurgårdsstaden drawn by Tengbom Arkitekter is going to be built. A shaft for airing is needed for a few apartments in the house. The airing shaft is designed for a few two room apartments in the house, which are not able to achieve satisfactory airing, as their outer walls are facing a single direction. The other apartments on the same floor are corner apartments. These apartments do not have the same difficulty with airing since they have their outer walls in different directions, with different pressures at the facades. The airflow in the airing shaft is supposed to be driven only by natural forces, by the sun. The purpose of natural driven forces is to achieve low energy consumption for the house.In this thesis, a design of the shaft for airing has been developed.Initially an open shaft for all apartments was analyzed. The shaft was not possible to implement due to risk of fire spread, acoustic problems and odor contamination between the apartments.Inspired by natural ventilation and the principle of double-skin facade, the idea of separate channels for each apartment with a glass facade on the outside emerged. The air in the channels is heated by solar energy on the glass facade to achieve a rising force in the channels.An air current is achieved in the apartment, through an opening to the shaft while a window is opened at the same time, due to the pressure difference. Through analytical calculations, the air flows in the channels are studied at different temperatures during the summer when the airing is most needed.Results show that it is possible to create a flow in channels with solar energy. According to the calculations, the air flow will be enough for airing of the two room apartments. Further studies are needed to ensure the shaft ability