![]() ![]() Fine particles (1 μm) follow the airflow pattern more strictly than coarse particles (7 μm), and the high ventilation effectiveness indicates better removal of fine particles than coarse particles. The results show that the relationship varies predominantly with airflow pattern and particle properties. This paper presents an experimentally and numerically based study that examines the relationship between ventilation effectiveness and particle concentration in typical indoor environments. Depending on pollutant properties and source position relative to the airflow, ventilation effectiveness can more or less successfully be used as an indicator of air quality and human exposure. It is a representation of how well a considered space is ventilated compared to a perfect air mixing condition. Ventilation effectiveness is an indicator of the quality of supply air distribution in ventilated rooms. The system also provides better thermal climate than mixing and displacement ventilation at elevated temperatures. Results show that the system qualifies to be used as a primary ventilation system and has local air change index >1 inside the jet, and a ventilation efficiency >50%. This paper presents an experimental evaluation/analysis of the proposed system with regard to ventilation efficiency and thermal comfort measurements in a classroom mockup. The jets coalesce into a single two-dimensional jet which is directed downwards in the sitting zone. The strategy uses ceiling mounted high momentum air jet diffusers (AJD) made from ventilation duct fitted with nozzles that generate confluent jets. This paper presents an experimental evaluation of a novel ventilation strategy for high occupancy spaces that provides fresh air and thermal comfort in the sitting zone through a controlled intermittent air jet system. Alternative ventilation strategies that optimize high air movements in the occupied zone allow human activities at elevated temperatures while attaining improve occupants' perception and acceptance of the indoor climate at a low energy use. To meet occupants' thermal comfort requirements traditional systems use a lot of energy. classrooms, auditoriums and restaurants, provide challenges to ventilate at a lower energy use due to elevated temperatures. Each ventilation system showed different airflow patterns and the efficiency of each ventilation system in the removal of the particles in the breathing zone showed no correlation with particle size and the various methods of analyses used. The efficiency of the ventilation system was analysed by measuring particle size and concentration, ventilation effectiveness and the indoor/outdoor ratio. The measurements aimed to analyse the particle removal efficiency in the breathing zone and the impact of particle concentration on an individual at the workstation. Measurements of particle concentration and thermal parameters (temperature and velocity) were carried out for each of the following types of ventilation systems: (a) conventional air distribution system with ceiling supply and return (b) conventional air distribution system with ceiling supply and return near the floor (c) underfloor air distribution system and (d) split system. In this study, four ventilation systems were used in a test chamber designed to represent an area of a typical office building floor and reproduce the real characteristics of a modern office space. ![]() Many factors affect the airflow patterns, thermal comfort, contaminant removal efficiency and indoor air quality at individual workstations in office buildings. ![]()
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