Calculation of airflow rate with displacement ventilation in dynamic conditions

Natalia Lastovets*, Risto Kosonen, Juha Jokisalo

*Corresponding author for this work

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


Design of displacement ventilation (DV) is usually based on a heat balance method when overheating is the primary indoor climate concern. Various models for calculating airflow rate have been developed for several decades. Commonly used models are based only on steady-state models. However, in practical applications, the performance of DV depends on potentially dynamic parameters, such as strength, type and location of heat gains and changing heat gain schedule. Besides, thermal mass affects dynamically changing room air temperature. The paper presents case studies of dynamic DV design in a lecture room. The difference in the designed airflow rate was studied with various models in both dynamic and steady-state conditions. The presented dynamic DV model demonstrated a capability to take into account the combination of dynamic parameters in typical applications of DV. In the case analysed, the airflow rate calculated with the dynamic model is significantly lower than the one calculated with the steady-state models
Original languageEnglish
Title of host publicationBuildSIM-Nordic 2020 Selected papers
Subtitle of host publication International Conference Organised by IBPSA-Nordic, 13th–14th October 2020, OsloMet
Place of PublicationOslo, Norway
Number of pages7
ISBN (Electronic)978-82-536-1679-7
Publication statusPublished - 12 Oct 2020
MoE publication typeA4 Article in a conference publication
EventBuildSim-Nordic - Online, Oslo, Norway
Duration: 13 Oct 202014 Oct 2020

Publication series

NameSINTEF proceedings
ISSN (Electronic)2387-4295


Abbreviated titleBSN
Internet address


  • displacement ventilation design
  • airflow rate
  • temperature gradient
  • dynamic model

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