Influence of the Inlet Size on the Natural Ventilation System Operation in a Residential Multi-storey Building

Abstract

When equipping the buildings with tight windows, the designers are required to take into account the aerodynamic resistance of the supply devices. The apartment plans, which became much more complicated over the past twenty years, resulted in increasing the number of prefabricated ducts of natural exhaust ventilation systems in each apartment of a residential house. Aerodynamic calculations of each exhaust system shall consider the ventilation paths starting from the outside air in the supply unit of a living room and ending above the exhaust shaft of the system. The results were obtained on the basis of the air mode calculations of the building as a whole. In this article, the calculation of the building air mode has been carried out by the iterative method. The object of the study was a section of a residential building with 18 residential floors equipped with natural ventilation systems. The article considers two options of the air inflow: through the swing-out window sash with 0.231 m2 open area and through the supply valves in each room of the apartment with 0.0036 m2 live section of one valve. It has been shown that in case of insufficient area of supply devices it is impossible to provide the ventilation air design flow rate under design ventilation conditions even with the help of air ducts of unrealistically large sizes.

Design of Natural Ventilation System to Ensure Standard Air Consumption

“…The assessment of the impact of the refusal to take into account the room pressures in aerodynamic calculations of the natural ventilation exhaust system has been performed by comparing the results of multivariate analysis of the building air mode on a computer and the manual calculation. The PC calculation analysis has been performed according to the program developed by us [25][26][27], and the manual aerodynamic calculations have been performed according to the generally recognized method of the building isolated system [3]. The options with the inflow through the opening rotary sash of a window and through the inflow valve have been considered.…”