Experiments were operated to determine the thermal stratification in a full-scale enclosure with natural ventilation driven by thermal source. Results provided by various predictive techniques were compared with experimental data. The salt-bath modelling technique and related mathematical model of Linden appear to be unappropriate for this type of air flow. CFD gives realistic predictions, especially when using a complete thermal radiation model.
Thanks to an environmental chamber equipped with a displacement ventilation system, neutral height measurements were carried out with the presence of a heated mannequin and other heat sources.The relationship between the neutral height for air distribution and the ventilation load in a room with displacement ventilation was investigated.
In this paper, the objective of the authors is to investigate the use of artificial neural networks for the prediction of air pressure coefficients across the openings in a light weight single-sided naturally ventilated test room.
That paper deals with the use of nondimensioanl graphs for designing the envelopes of naturally ventilated buildings. The graphs can be generated from theoretical models or from experimental data via a direct measurment of ventilation rates in a wind tunnel model.
Examples of graphs are given: they cover conventional design conditions and off-design conditions.
Experimental data for an impinging jet in a room are presented in this paper and non-dimensional expressions for the decay of maximum velocity over the floor are derived. The performance of that system is compared with the one of a wall displacement ventilation.
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.
A new Adaptive Comfort Standard is included in the recently accepted revisions to Ashrae standard 55. That ACS permits warmer indoor temperatures for naturally ventilated buildings during summer and in warmer climate zones. It is based on the analysis of 21,000 sets of raw data compiled from field studies in 160 buildings located in different climatic zones on the 4 continents.
The author explains that too tight building envelopes can cause bad operation of atmosperically vented combustion systems (e.g. gas water heaters) in case of of unintended depressurization of the building, for example with large exhaust fans and dirt filters. He considers that airtightness requirements of standards are often too severe. He proposes a building airtightness of 2 to 6 air changes per hour at 50 Pa for warm climates and 1.5 to 4 for cold climates, buildings with atmospherically vented combustion appliances being at the high end of the range or higher.
This article analyses and comments 5 papers presented at Indoor Air 2002 Conference (see Airbase records 14454, 14455, 14539, 14695 and 14697) about indoor air quality and filters, from the point of view of filter changing frequency.
An analysis of recently published research results is provided, showing that if molds and the different compounds they produce can lead to some health effects (allergies, infections, potential toxicologic effects) when inhalated, these effects occur only for exposures at very high doses. The potential toxicity from indoor air exposures is therefore very low, which allows to consider the term 'toxic mold' as a misnomer.