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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. The linear regression slope of 0.70 and intercept of 0.Many factors affect the airflow patterns, thermal comfort, contaminant removal efficiency and indoor air quality at individual workstations in office buildings. Modeled breathing zone concentrations were statistically correlated (p-value < 0.001) with independently collected ABS concentrations. Both models predicted probability distributions of asbestos breathing zone concentrations that bracketed experimentally measured personal exposure concentrations. A Monte Carlo simulation calculated the breathing zone concentration probability distribution for each scenario. A Lagrangian model tracked the cumulative number of individual particles entering the breathing zone volume at a particular time. The second scenario modeled exposure in a quiescent environment. One scenario used an Eulerian model based on a Gaussian concentration distribution to quantify aerosol exposure in the trailing wake of a moving object.
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The model predicted the particle emission rate, tracked particle transport to the breathing zone, and calculated the breathing zone concentration for two scenarios. As an alternative approach, a probabilistic model based on aerosol physics and fluid dynamics was developed to predict the breathing zone concentration of a particulate contaminant emitted from a surface during activities of variable intensity. Activity based sampling determines the contaminant concentration in a person's breathing zone as they perform a scripted activity, such as raking a specified area of soil, while wearing appropriate sample collection instrumentation. Activity based sampling (ABS) is typically performed to assess inhalation exposure to particulate contaminants known to have low, heterogeneous concentrations on a surface.