Position of exhaust air openings and the contaminant removal efficiency of displacement ventilation

Arto Säämänen, Matti Lehtimäki

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review


Displacement ventilation is used in many industrial premises due to its good energy efficiency characteristics and ability to create good air quality to the occupied zone. However, it has been observed that many kinds of disturbances can break down this stratification. This presentation is concerned with the possibilities to enhance the stability of the stratification and thus, the contaminant removal effectiveness of the displacement ventilation. Experiments were carried out in a test room with displacement ventilation system and an adjustable heat source. Location of exhaust opening in relation to the combined heat and tracer gas source was varied. Also, the effect of segmentation of stratification zone was tested. Measurements of the age of the contaminant as well as relative concentration of tracer gas in different location of the room were tested. The results indicated that the contaminant concentration at the occupied zone could be decreased by 50 % simply locating the exhaust opening to the position where the plume reached the ceiling. Further improvement was achieved by using the segmentation of the stratified zone together with correct position of the exhaust openings. The results imply that the age of the contaminant has to be kept as short as possible and thereby the exhaust has to be centralised to the areas where the emission is highest. The results can be utilised in designing of displacement ventilation.
Original languageEnglish
Title of host publicationProceedings of the 7th International Symposium on Ventilation for Contaminant Control, Ventilation 2003. Sapporo, JP, 5 - 8 Aug. 2003
Place of PublicationSapporo, Japan
Pages297 - 302
Publication statusPublished - 2003
MoE publication typeA4 Article in a conference publication


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