Field comparison study of indoor environment quality in office buildings with underfloor and overhead ventilation systems

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Proceedings titleASHRAE Transactions
ConferenceASHRAE 2014 Annual Conference, June 28-July, 2014, Seattle, WA, USA
SubjectUFAD; mixing ventilation; office building; IAQ; predicted thermal comfort
AbstractThe use of UFAD (Underfloor Air Distribution) systems is increasing rapidly and reported advantages of UFAD include energy savings and improved indoor air quality. At present few publications documenting measurements of ventilation effectiveness and indoor environment quality in occupied buildings with UFAD have been identified. In this field comparison study we measured several aspects of the thermal environment in two buildings with different ventilation systems (underfloor air distribution and mixing) located in Montreal (Quebec). The results are presented in terms of thermal stratification, predicted thermal comfort indices (VATD , limit to air speed and PMV/ PPD), and IAQ index (CO2 level and stratification). The aim of the study was to determine whether UFAD in practice results in improved ventilation effectiveness compared to typical overhead air distribution without affecting the thermal comfort. The study found that there was little stratification for UFAD under operating conditions and it performed as a mixing system, thus no improvement in ventilation effectiveness was identified in the occupied zone, in comparison to the reference mixing system. In addition the predicted thermal comfort in term of VATD, air speed and PMV/PPD was similar to those obtained for mixing ventilation and was within the acceptable limits set by ASHRAE 55-2010.
Publication date
AffiliationNational Research Council Canada; Construction
Peer reviewedYes
NRC numberNRC-CONST-56151
NPARC number21275443
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Record identifierf7ceb901-de1e-4109-9dac-5074c2dfe5ad
Record created2015-07-14
Record modified2017-04-05
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