In displacement ventilation the airflow pattern in a room is mainly guided by the convection flows from the heat sources present in the room. This implies that the air in the breathing zone mostly comes from the lower parts of the room, where the air often is less polluted by pollutants originating from persons or electrical appliances present in the room.
The Particle Streak Tracking System (PST) is a fast method to measure two- and three-dimensional velocity fields in room air flows with measuring areas up to 5 m2. The two-dimensional method works with a single pulsed white light sheet and one digital camera. For three-dimensional velocity measurements in planes a laser light sheet system using three separate laser sheets with two different wavelengths and two CCD-cameras is employed. To visualise the flow helium filled bubbles are used. A description of the set-up will be given and the data evaluation process will be explained.
The airborne transmission of disease is a constant threat and while diseases such as Tuberculosis were considered all but extinct in the western world, the resurgence of it demonstrates that the spread of these diseases has to be taken very seriously. This paper describes the method of application of Computational Fluid Dynamics (CFD), more appropriately called Airflow Modelling for the Building Services Industry, to the airflow and heat transfer in a Hospital Isolation Room Application.
Field studies were carried out on air contamination by dust particles from air conditioning systems in four buildings in Tokyo area. We tried to investigate contamination of airborne particle and surface contamination by sedimentary dust in air duct, and considered a matter in all its aspects that caused indoor air pollution.
1. Time variations of airborne particle concentrations at supply outlet were influenced by the operation of air conditioning system.