The effect of the change in object positions (i.e. office furniture) on the air quality in a room was studied using zonal purging flow rates. In relation to the zonal purging flow rate in a room, the transfer probability from the inlet to a certain zone can provide information on the amount of fresh air from the inlet to the zone. In this study, the probability obtained from Markov chain theory was used to analyze the ventilation performance.
Experimental investigations and practical experiences in Europe have proved that hydronic cooled ceilings are able to remove high cooling loads without impairing thermal comfort. As hydronic cooled ceilings cannot remove latent loads and pollutants, e.g., C02, VOCs, odors, additional ventilation has to be applied. Often, displacement ventilation is used, which is able to provide lower pollutant levels in the occupation zone than mixing flow systems, if the occupants are causing most of the pollution.
An environmental chamber has been used to compare the effectiveness of mixing and displacement ventilation in terms of heat and contaminant removal. Results are presented for CFD simulations of the air movement in the chamber and for measurements using a heated mannequin with displacement ventilation. The CFD simulations and the measurements suggest that displacement ventilation is more energy efficient than a mixing system.
This study focuses on the way to apply CEN test methods to a full range of air diffusers and is dedicated to the improvement of these methods proposed by the CEN TC l 56/WG4 of which both authors are members. Air terminals of different sizes have been tested on aerodynamic and acoustic aspects both in a Spanish and a French laboratory. The tests were made according to pr EN 12238 ''Air Terminal devices - Aerodynamic testing and rating for mixed flow applications" and to EN 25135 (ISO 5135).
The ventilation engineer's plan at the design stage could be influenced by many factors. It may also be different from the requirements for the final users of the spaces. In case of open-space design, which is getting popular due to its flexibility. It is more difficult to provide adequate ventilation to control the indoor air quality. Specially, when partitioning of the space is employed.
In modem livestock buildings the design of the ventilation systems is important in order to obtain good air distribution. The use of Computational Fluid Dynamics for predicting the air flow and air quality makes it possible to include the effect of room geometry, equipment and occupants in the design of ventilation systems. However, it is not appropriate to include the detailed geometry of a large group of lying or standing animals affecting the air flow in the building. It is necessary to have relatively simple models of the animals, which are easier to implement in the computer models.
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