The paper presents a comparison between the results of experimental tests airflow pattern forming in a room with displacement ventilation and numerical calculation. The heat source in the room was a heating plate. Quasi-laminar diffusers supplied the air with the ventilation change rate from l to 7 h-1. Temperature and velocity distributions in the plume and in its surroundings as well as the tracer gas concentrations in the background were measured. The airflow in the room was also predicted by means of CFD, using the standard k-E turbulence model and standard log-law wall-functions.
This paper is based on a dual approach (experimental and numerical) in order to predict the indoor air quality for small ventilated enclosures. The experimental part employs a ventilated test room and a tracer gas technique (constant method as gas injection) to estimate the diffusion of a pollutant. The gas used is the sulphur hexafluoride (F6S). The numerical approach is a CFD simulation, adding a convection - diffusion equation (to determine the local mass fraction of the pollutant) to the equations normally used to solve a turbulent flow.
The New Zealand Building Code has kept with tradition in allowing residential building ventilationdesigns based entirely on openable window areas. Working against this tradition, however, is a trend inNew Zealand towards more airtight construction and declining reliance on open windows. Contributingto this trend are changing patterns of occupancy with fewer people at home during the working week,along with developing concerns for personal security.
The air quality in a subway-train was studied to suggest optimal design criteria and operationconditions based on the ventilation demand by passengers. The C02 emitted from thepassengers was the tracer for this study. The C02 bioeffluent from a human body was firstlyquantified and used for the data analysis. Then the C02 concentration was monitored in asubway-train being operated.
The ventilation engineer's plan at the design stage could be influenced by many factors. It may also be different from the requirements for the final users of the spaces. In case of open-space design, which is getting popular due to its flexibility. It is more difficult to provide adequate ventilation to control the indoor air quality. Specially, when partitioning of the space is employed.
Few detailed comparisons of modeled ad measured pollutant concentrations in multizonebuildings have been published. The COMIS air flow and contaminant transport modelpermits simulation of the effects of building and HVAC operation, as well as the influence ofthe local meteorology, on air flows within the building. We have recently used this model tosimulate the release of a gas-phase tracer in a three-story, multi-room building located atDugway Proving Ground, Utah, USA.