Tracer gases are often used to assess airflow rates in air handling units. Published methods aremostly designed for units with recirculation ratios lower than those commonly found inSingapore and other tropical countries. Large recirculation ratio homogenize theconcentrations, so that concentrations in supply and extract ducts are close to each other. Inaddition, such units often present a large time constant, so the time needed to reachequilibrium is very large. A procedure for tracer gas dilution technique adapted to such airhandlingunits is presented.
Tracer gas sorption in and permeation through building materials influence tracer gas ventilationmeasurements. Therefore, it is important to have knowledge about these processes.The permeation of three commonly used tracers (SF6, N2O and the PFT C6F6) through untreatedgypsum board has been experimentally investigated. The result shows that all three tracers diffusereadily through this material (diffusion coefficients in the order of 1 10.-6 m2/s). Caution shouldtherefore be exercised when using tracer gas measurements in rooms with walls of gypsum boardor other porous materials.
The purpose of this study is to estimate the accuracy of the Supply Rate Fulfilment (SRF)value measured by using tracer gas on a test house. The SRF is intended to evaluate quantityindex and is defined as the ratio of the effective supply rate to the substantial required freshair supply rate. The procedures to measure the SRF value with use of tracer gas techniques,which are constant concentration method and constant injection method, were shown. TheSRF values of the each room in the test house were measured.
In the present paper, the influence of the initial inclination angle of the jet on the efficiency ofa vertical downward air curtain is analysed. The air curtain device was mounted over anoverture, in the wall between two equal contiguous rooms, with the typical dimensions of adoor.
Single- and double-section manufactured homes were instrumented in 2001-2003 to measure continuous energy usage and air infiltration with respect to the environmental conditions of a windy cold dry climate. The test site near Arlington, Wyoming, USA is ideal for testing the energy (and structural) performance of manufactured housing due to the naturally occurring high winds (in excess of 35 m/s annually) and temperature extremes (+35 to -35C). Tests included tracer gas monitoring, pressurized leakage tests, and infrared (IR) video scans.
To provide additional validation data for the multizone airflow and contaminant model, CONTAMW, experiments were performed in an occupied 3-story townhouse in Reston, VA. A tracer gas, sulfur hexaflouride (SF6), was manually injected within one room of the house and the concentration of SF6 was measured in each zone. This same process was then recreated in CONTAMW and the resulting predictions were statistically compared to the measured values. A total of 10 experiments were conducted and simulated between May 2000 and June 2001.
This paper describes a new tool, ils architecture and its predictive performance. BACH is a computational tool for air flow simulation in and around buildings in the early stages of the design process.
Airflow measurements techniques are necessary to determine the most basic of inddoor air quality questions : "Is there enough fresh air to provide a healthy environment for the occupants of the building?" . This publication outlines airflow measurement techniques, but it does not make recommendations for techniques that should be used. The airflows that are discussed are those within a room or zone, those between or zones, such as through doorways (open or closed) or passive vents, those between the building and outdoors, and those through mechanical air distribution systems.
This work, along with the experimental measurements on which it is based, was carried out in the framework of research undertaken by the French “Groupe de Pilotage sur la Qualité des Ambiances” (GPQA), whose task was to initiate and co-ordinate work on ai
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.
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