ventilation

Environmental and economic concerns linked to conventional heating, ventilation and air-conditioning systems (HY AC) have sparked a renewed interest in natural ventilation, passive cooling and other low energy microclimate control strategies for buildings. In Canada, the combination of extreme weather conditions, wind variability, transient occupancy patterns and high internal heat gains may hinder the feasibility of implementing natural ventilation as an exclusive means of ventilating non-domestic buildings.

Natural ventilation systems for industrial buildings have traditionally been designed using empirical engineering models, which often require the designer to 'over-engineer' the design to achieve a 'guaranteed' level of ventilation performance. This paper describes an application of computational fluid dynamics (CFD) and multi-zone thermal and airflow modelling to analyse the effectiveness of natural ventilation in removing moisture from a red mud filtration building used in the alumina industry in Australia.

The aim of this study is to improve the utilization of CFD approach in the applications of air conditioning technology. More precisely, to establish principles and recommendations to follow in order to design air distribution systems in small enclosures at low room air changes per hour by means of CFD technique. By the use of a commercial code, Fluent, the accuracy and reliability of such a numerical simulation are elucidated in this work for a mixing ventilation system; the air supply terminal is a commercial diffuser which creates a complicated 3D - wall jet below the ceiling.

This paper reports on an investigation of the use of an innovative earth tube ventilation system designed to improve the internal comfort conditions without the need for mechanical cooling. The numerical model and computer simulation developed for the prediction of air and soil temperatures has been made. The paper demonstrates the accuracy of this model and describes the results of analysis.

This paper presents a summary of calculations on the total cost effects of the remedial measures to reduce high summer time room temperatures in a hypothetical building. In the base case the room air temperature is too high during the summer, and causes a considerable reduction in the productivity. The following economical items are included in the study: first cost of the remedial measure, the effect of the measure in operating cost, particularly on energy consumption, and the effect on productivity.

The provision of a healthy and satisfactorily clean indoor environment requires that consideration be given to a range of issues, such as the type of indoor environment, indoor and outdoor sources, indoor activity and others. The selection of relevant measures to achieve the required indoor air quality (IAQ) depends on knowledge and understanding of the mechanisms and parameters affecting the concentration levels indoors.

Gas cooking in the home can release high levels of nitrogen dioxide (N02) and carbon monoxide (CO). This study investigated the effect of various ventilation strategies to reduce personal exposure to these pollutants. It considered the effectiveness of windows, a kitchen extract fan and trickle ventilators for different dwellings, occupant behaviour, environmental conditions etc. Strategy selection was based on the need to minimise both personal exposure and energy loss. These strategies were simulated using BRE's BREEZE multi-zonal computer code.

Epidemiological studies suggest that cooking with gas leads to an increase of air pollutants and may enhance symptoms of respiratory diseases. However, little experimental data are available concerning the emission of pollutants due to different cooking processes. The goal of this study was to investigate the influence of cooking under standardized conditions on the indoor air quality. A model kitchen was built and three different gas stoves and one electric stove were included in the study. Two different menus were prepared with different settings of the ventilation rate of the exhaust.

Air may be pre-cooled using thermal mass before it is supplied to an occupied space. One option is to pre-cool the air in a basement space and exhaust the air at high level through stacks. However, the thermal forces that determine the direction of airflow, including heat gains in the occupied space, thermal mass cooling and the external air temperature may counter each other, and result in flow reversal.