Performance of displacement ventilation in Canadian schools: field studies

Displacement ventilation systems take a fundamentally different approach to space conditioning than the systems found in the majority of commercial buildings, which currently use a fully mixed and dilution approach to ventilation. Displacement ventilation (DV) is an alternate air distribution method for commercial spaces, in particular schools. Previous research has shown that this type of system works well for regions where buildings require year-round cooling, however there are a growing number of buildings using this approach in Canada, where buildings require heating during winter months. A series of field studies in existing Canadian schools were carried out during the heating season over the last three years. This paper presents results from field studies conducted in schools designed for displacement ventilation with a perimeter radiant heating system. We measured several aspects of the performance of a DV systems installed in schools located in different parts of the country. The results show that the measured contaminant removal effectiveness was higher than that provided in previous studies for heating mode. In addition, key predictors of thermal comfort are also generally within limits set by ASHRAE standards. The results of these field studies provide some evidence of thermal comfort and IAQ-related benefits of DV in cold climate. However, before general conclusions are drawn, the benefits need to be confirmed in other studies.Peer reviewed: YesNRC publication: Ye