AIVC - Air Infiltration and Ventilation Centre

Search form


You are here


air flow

Presumption experiment of supply rate fulfilment using tracer gas verification on the cylinder house

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.

Tracer gas measurement of airflow rates in rooms with several air-handling units

Methods to measure airflow rates using tracer gas in single air handling units are well known.However, in some buildings, in particular in Singapore, rooms are often ventilated with two ormore units. An adapted methodology that should be used to measure not only the airflow ratesprovided by each unit, but also to determine the inter-units airflow rates and the globalventilation efficiency is presented.

Indoor air quality and airflow distribution as a new factor in surgical operating theatres: a new hypothesis

This paper reviews the previous attempts to evaluate the Indoor Air Quality (IAQ),investigates previously proposed IAQ factors and analyses the evaluation methods of thesefactors. The present work also introduces a new hypothesis of the optimum HVAC airsidesystem design of the surgical operating theatres to achieve the comfort and hygiene levels.The present work is devoted to propose and formulate a new scale capable of adequatelyevaluating the airflow pattern in the surgical operating theatres. The proposed new scale isproposed to cover the local and overall air quality evaluations.

Influence of geometry of thermal manikins on room airflow

A number of different thermal manikins have been applied in literature to experimentallystudy the indoor environment. These manikins differ in size, shape and level of geometriccomplexity ranging from simple box or cylinder shaped thermal manikins to humanlikebreathing thermal manikins. None of the reported studies, however, deals with the influenceof geometry of the thermal manikin.

Development of an extraction equipment for preventing the transmission of contaminant exhaled air

In 2003, the World Health Organization received reports of ‘Severe Acute Respiratory Syndrome (SARS)’ in various parts of the World. Until 13 June 2003, there were 1755 people affected by atypical pneumonia in Hong Kong. While the mechanisms of the SARS a

The ups and downs of airflow in building ventilation

Almost all existing analysis methods for building ventilation airflows, such as the simpleanalytical methods, multi-zone methods and computational fluid dynamics (CFD), give onlyone unique solution for one set of identical input parameters when started with zeroinitialization or zero initial conditions. This can be shown to be incorrect in some situations.Multiple stable solutions are found in some very simple buildings, which indicate that thebuilding airflows are of a nonlinear dynamical system.

The effects of direct and indirect airflow on thermal comfort

A spot cooling system using the convective cooling effect of an air stream is known to beeffective by its smothering intensive hot environment, supplying comfort sense and utilizingenergy efficiently. However, its study on the interaction with human body or product itself isuncommon, showing that the spot cooling system intrinsically contains the possibility ofdraught because of its short emitting distance from the object, low air temperature, high airstream velocity and its direct local contact to human body.

Thermal mixing of outdoor and return airflows in typical air-handling units

This paper examines thermal mixing of outdoor and return airstreams in typical air-handling units equipped with parallel blade dampers. The mixing of the two airstreams in rectangular and square mixing chambers is studied for eight different dampers and blade orientations. Testing is conducted at a total supply air of 16000 CFM with outdoor flow percentages of 15% and 30%. The temperature differential between the outdoor and return airflows is kept at 40F. Damper blades with chords of 4 and 6 inches are tested.

An Algorithm of Stereoscopic Particle Image Velocimetry for Full-Scale Room Airflow Studies

One challenge in indoor air quality studies is the measurement of three-dimensional air velocity profiles in an airspace so that the nature of airflow can be better understood and appropriate ventilation systems can be designed. There is much dispute over a variety of computational fluid dynamics (CFD) models, primarily due to a lack of credible data to validate those models. This study aimed to develop a stereoscopic particle imaging velocimetry (SPIV) system suitable for easurement of full-scale room three-dimensional airflow.

An integrated zonal model for predicting airflow and VOC concentration distributions in a room

An Integrated Zonal Model was developed to predict the three-dimensional airflow andcontaminant concentration distributions in a room. This model integrated a zonal model withmaterial emission/sink models. This Integrated Zonal Model was applied to a mechanicallyventilated room to simulate airflow pattern and VOC concentration distributions. Results werecompared with prediction made by a CFD model. It was found that the Integrated ZonalModel could provide sufficiently reliable results and some global information regardingairflow pattern and VOC distributions within a room.