30 human subjects participated in a 3 h 45 min. experiment, that took place in an office with mixing ventilation and personalised ventilation systems (PVS).Each person could choose the position of the personal air terminal device, the direction of the air supplied and the flow rate (up to 15 l/s.person).The subjects were exposed to 4 following experimental conditions : PVS supplying outdoor air at 20C, then 23C ; PVS supplying re-circulated room air ; mixing ventilation, without PVS.Results allow to know how the PVS were used by participants (choice of position and flow rate).
At first, this paper deals with the history of indoor environment and ventilation , with the evidence that a good IAQ is essential for public health. An inadequate ventilation plays a major role on the global burden of allergies, airways infections. The more complex the HVAC system is, the more liable it is to fail (if improper maintenance) sothe non-industrial indoor environment is the most important environment from a human health perspective.
This paper deals with the development of 2 approaches for the modelling of the transport of gaseous pollutant with CFD code Fluent. The pollutant is either considered as a scalar and modelled with a transport equation, or it is described through species transported modelling. The 2 methods are presented and the results compared to those obtained from an experiment made in a test cell with tracer gas SF6.
Advances in infection control practices include improved operating room environment (airflow velocity, turbulence level, temperature, and relative humidity). Operating theatres are complex spaces. CFD modelling is a powerful tool to enhance the knowledge of the air characteristics. The 3DHVAC program was used to predict the performance of HVAC system design in operating theatres of a 1200-beds Egyptian modern teaching hospital.
This paper deals with the CFD (Computational Fluid Dynamics) method used for the analysis of the micro-climate surrounding the human body. The airflow characteristics of inhalation and exhalation are analysed under both steady and unsteady breathing conditions. The various examples given in this report make clear that CFD is a very effective and powerful tool for analysis and design of healthy indoor environments.
The study in 5 European countries has shown that indoor air quality was noted depending on the country first and on the perceived thermal comfort. Moderate humidity is perceived better while temperature in comfort zone less influence indoor air quality. When it is too hot or too humid, indoor air quality is badly perceived. CO2 levels have few relationship with perceived indoor air quality.
This paper discusses architectural design of buildings for a good indoor air quality, material selection, building design process, relationships between indoor and outdoor air quality. It shows that the roles of architects and engineers are complementary to obtain a good indoor air quality.
A thermal manikin with a simulated lung was placed in an air-conditioned office with fresh air supplied in close proximity to the facial area at flow rates from 0.1 to 2 l/s. CO2 concentration measurements allow to define the fresh air utilization efficiency and the pollutant exposuer reduction efficiency.
This paper examines the performance of five different air terminal devices for personalized ventilation in relation to the quality of air inhaled by a breathing thermal manikin in a climate chamber. The personalized air was supplied either isothermally or non-isothermally (6 C cooler than the room air) at flow rates ranging from less that 5 l/s up to 23 /s. The air quality assessment was based on temperature measurements of the inhaled air and on the portion of the personalized air inhaled. The percentage of dissatisfied with the air quality was predicted.
Experiments with 30 human subjects were performed in an office equipped with personalized ventilation systems (individual control of flowrate and direction) for 6 workers and with different supply air temperatures to analyse perceived air quality and sick building symptoms.
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