Vis enkel innførsel

dc.contributor.authorToivo, Säwén
dc.contributor.authorStockhaus, Martina
dc.contributor.authorHagentoft, Carl-Eric
dc.contributor.authorBunkholt, Nora Schjøth
dc.contributor.authorWahlgren, Paula
dc.date.accessioned2021-11-16T07:31:10Z
dc.date.available2021-11-16T07:31:10Z
dc.date.created2021-02-22T08:30:13Z
dc.date.issued2021
dc.identifier.issn1744-2591
dc.identifier.urihttps://hdl.handle.net/11250/2829705
dc.description.abstractTimber roof constructions are commonly ventilated through an air cavity beneath the roof sheathing in order to remove heat and moisture from the construction. The driving forces for this ventilation are wind pressure and thermal buoyancy. The wind driven ventilation has been studied extensively, while models for predicting buoyant flow are less developed. In the present study, a novel analytical model is presented to predict the air flow caused by thermal buoyancy in a ventilated roof construction. The model provides means to calculate the cavity Rayleigh number for the roof construction, which is then correlated with the air flow rate. The model predictions are compared to the results of an experimental and a numerical study examining the effect of different cavity designs and inclinations on the air flow rate in a ventilated roof subjected to varying heat loads. Over 80 different test set-ups, the analytical model was found to replicate both experimental and numerical results within an acceptable margin. The effect of an increased total roof height, air cavity height and solar heat load for a given construction is an increased air flow rate through the air cavity. On average, the analytical model predicts a 3% higher air flow rate than found in the numerical study, and a 20% lower air flow rate than found in the experimental study, for comparable test set-ups. The model provided can be used to predict the air flow rate in cavities of varying design, and to quantify the impact of suggested roof design changes. The result can be used as a basis for estimating the moisture safety of a roof construction.
dc.language.isoeng
dc.subjectAir flow
dc.subjectBuilding envelope
dc.subjectRoof construction
dc.subjectAnalytical model
dc.subjectCavity ventilation
dc.titleModel of thermal buoyancy in cavity-ventilated roof constructions
dc.typePeer reviewed
dc.typeJournal article
dc.description.versionpublishedVersion
dc.rights.holder© 2021 The Authors.
dc.subject.nsiVDP::Teknologi: 500
dc.source.journalJournal of Building Physics
dc.identifier.doi10.1177/1744259120984189
dc.identifier.cristin1892167
dc.relation.projectNorges forskningsråd: 237859
cristin.ispublishedtrue
cristin.fulltextoriginal
cristin.qualitycode2


Tilhørende fil(er)

Thumbnail

Denne innførselen finnes i følgende samling(er)

Vis enkel innførsel