Recently indoor air quality (IAQ) became an important issue and as a result researchers have developed a large number of different air quality indicators. This study focuses on air exchange efficiency (ea) and contaminant removal effectiveness (e) as suitable indicators for use in design and on-site measurements. These two IAQ indicators were numerically studied and compared for five typical indoor spaces with different ventilation strategies and contaminant sources. Overall,
On account of Volatile Organic Compounds (VOCs), large proportions of workers suffer from eye and respiratory discomfort or headaches. In a small-scale painting process, efficient ventilation system must be provided for human health. In this study, ventilation characteristics of toluene have been analysed in a room of a small-scale painting process with various exit locations with different suction velocities at the exits.
Seven air supply and return diffusion layouts were tested to determine their effects on air distribution, air change efficiency and ventilation efficiency for workstations in an open-plan office. This document describes and comments the results of these measurements.
Variations in heat source positions in a room bring changes in the ventilation effectiveness. Those changes are studied using experimental data and CFD results. Results show that a good ventilation effectiveness can be achieved when the contaminant and the heat source are located close to the zone containing the exhaust opening.
Describes a study based on experimental work carried out in the full-size MiniBat experimental cell, comprising two zones separated by a wall and a door. Experiments were carried out in a steady state, under isothermal and non-isothermal conditions, with a heating system and a manikin. To determine ventilation effectiveness the tracer gas method was used. It was injected into zone 1 and two positions were examined. The study concluded that the heating system favoured the mixing of the air in the cell, which means that the ventilation effectiveness was always close to one.
Ventilation effectiveness is an important means to describe and evaluate the performance of a ventilation system. In terms of ventilation tasks, this paper presents a unified physical model for the ventilation efficiency scales based on conservation principles to which a ventilation system should conform. Transport equations for the local mean age of air and contaminant are respectively obtained, which can be integrated solved by the CFD program. To validate the proposed model and CFD simulation of the ventilation efficiency, a 2-D laminar ventilation flow is analysed.
Currently, in the design of new buildings and retrofit of old buildings, attention is turning towards a more integral energy design with focus not only on thermal insulation and airtightness but also on optimal use of sustainable technologies such as natural ventilation. There is a tendency for buildings to be designed in order to utilise the outdoor environment to create an acceptable indoor environment, whenever it is beneficial. Passive ventilation and natural cooling are sustainable energy efficient and clean technologies.
This study is a part of a research project called 'Convective Flows and Vertical Temperature Gradient within Active Displacement Air Distribution'. The project and the two zone model developed have been introduced by Sandberg (1). The aim of this study was to examine the ventilation effectiveness with different elevations and horizontal positions of the heat sources within active displacement air distribution. This was studied by carrying out experiments using convective heaters and ordinary fluorescent tube lamps at several elevations as heat sources.
The evaluation of the ventilation effectiveness and thermal comfort for various industrial ventilation schemes has been carried out by 1:4 scale model experimentation. Measurements of air speed, temperature, and contaminant concentration allowed the contaminant removal and thermal comfort to be quantified using ventilation effectiveness and thermal comfort indices, respectively. Archimedes number scaling was used to convert the small scale measurements to full scale conditions. The ventilation efficiency generally increased when the heat load was increased and/or the flow rate decreased.
The protection of non-smoking persons against cigarette smoke is a very popular subject. In Germany the ,pro' and , contra' of non-smoking regulations especially in public accessible areas like restaurants, train stations or in governmental buildings is discussed in a more and more controversial way. Especially the discussion about passive smoking and negative health effects through passive smoking lead to the demand of an effective protection of nonsmokers.