- Passive ventilation and heating in a multi-storey structure, by natural convection in a heated vertical duct were studied. Experimental study and computer simulations were first performed in a scaled-down laboratory model, divided into three levels, and connected by a duct, in which an electrically heated plate was used. The experiments included temperature and velocity measurements at each inner space, and inside the duct. The results obtained from the simulations and supported by the measurements, indicated that effective ventilation and heating, by the proposed method, were achievable in the laboratory structure. For a real-size structure of a five-storey building, which has a duct heated by solar irradiation, computer simulations were performed. Temperature fields and average temperatures were obtained at all levels of the building. The results have shown that even at low solar irradiation fluxes ventilation was achieved in summer, and heating in winter. The study has demonstrated that the proposed method is operable and feasible.