Thermal CFD Analysis of Tubular Light Guides

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dc.contributor.authorŠikula, Ondřejcs
dc.contributor.authorMohelníková, Jitkacs
dc.contributor.authorPlášek, Josefcs
dc.coverage.issue12cs
dc.coverage.volume6cs
dc.date.issued2013-12-03cs
dc.description.abstractTubular light guides are applicable for daylighting of windowless areas in buildings. Despite their many positive indoor climate aspects they can also present some problems with heat losses and condensation. A computer CFD model focused on the evaluation of temperature distribution and air flow inside tubular light guides of different dimensions was studied. The physical model of the tested light guides of lengths more than 0.60 m proves shows that Rayleigh numbers are adequate for a turbulent air flow. The turbulent model was applied despite the small heat flux differences between the turbulent and laminar model. The CFD simulations resulted into conclusions that the growing ratio of length/diameter increases the heat transmission loss/linear transmittance as much as by 50 percent. Tubular light guides of smaller diameters have lower heat transmission losses compared to the wider ones of the same lengths with the same outdoor temperature being taken into account. The simulation results confirmed the thermal bridge effect of the tubular light guide tube inside the insulated flat roof details. The thermal transmittance of the studied light guides in the whole roof area was substituted with the point thermal bridges. This substitution gives possibility for simple thermal evaluation of the tubular light pipes in roof constructions.en
dc.description.abstractTubular light guides are applicable for daylighting of windowless areas in buildings. Despite their many positive indoor climate aspects they can also present some problems with heat losses and condensation. A computer CFD model focused on the evaluation of temperature distribution and air flow inside tubular light guides of different dimensions was studied. The physical model of the tested light guides of lengths more than 0.60 m proves shows that Rayleigh numbers are adequate for a turbulent air flow. The turbulent model was applied despite the small heat flux differences between the turbulent and laminar model. The CFD simulations resulted into conclusions that the growing ratio of length/diameter increases the heat transmission loss/linear transmittance as much as by 50 percent. Tubular light guides of smaller diameters have lower heat transmission losses compared to the wider ones of the same lengths with the same outdoor temperature being taken into account. The simulation results confirmed the thermal bridge effect of the tubular light guide tube inside the insulated flat roof details. The thermal transmittance of the studied light guides in the whole roof area was substituted with the point thermal bridges. This substitution gives possibility for simple thermal evaluation of the tubular light pipes in roof constructions.en
dc.formattextcs
dc.format.extent6304-6321cs
dc.format.mimetypeapplication/pdfcs
dc.identifier.citationEnergies. 2013, vol. 6, issue 12, p. 6304-6321.en
dc.identifier.doi10.3390/en6126304cs
dc.identifier.issn1996-1073cs
dc.identifier.orcid0000-0002-7661-0732cs
dc.identifier.orcid0000-0002-5853-078Xcs
dc.identifier.orcid0000-0002-0509-1912cs
dc.identifier.other103274cs
dc.identifier.researcheridJ-4390-2012cs
dc.identifier.researcheridB-6585-2018cs
dc.identifier.researcheridF-7548-2013cs
dc.identifier.scopus55053563200cs
dc.identifier.scopus22980983700cs
dc.identifier.scopus55099842900cs
dc.identifier.urihttp://hdl.handle.net/11012/69288
dc.language.isoencs
dc.publisherMDPIcs
dc.relation.ispartofEnergiescs
dc.relation.urihttp://www.mdpi.com/1996-1073/6/12/6304cs
dc.rightsCreative Commons Attribution 3.0 Unportedcs
dc.rights.accessopenAccesscs
dc.rights.sherpahttp://www.sherpa.ac.uk/romeo/issn/1996-1073/cs
dc.rights.urihttp://creativecommons.org/licenses/by/3.0/cs
dc.subjectcomputer simulationen
dc.subjectANSYS Fluenten
dc.subjectCFD modelen
dc.subjecttubular light guidesen
dc.subjectthermal bridgesen
dc.subjecttemperature distributionen
dc.subjectair flowen
dc.subjectthermal radiationen
dc.subjectdiscrete transfer radiation modelen
dc.subjectcomputer simulation
dc.subjectANSYS Fluent
dc.subjectCFD model
dc.subjecttubular light guides
dc.subjectthermal bridges
dc.subjecttemperature distribution
dc.subjectair flow
dc.subjectthermal radiation
dc.subjectdiscrete transfer radiation model
dc.titleThermal CFD Analysis of Tubular Light Guidesen
dc.title.alternativeThermal CFD Analysis of Tubular Light Guidesen
dc.type.driverarticleen
dc.type.statusPeer-revieweden
dc.type.versionpublishedVersionen
sync.item.dbidVAV-103274en
sync.item.dbtypeVAVen
sync.item.insts2025.10.14 14:23:23en
sync.item.modts2025.10.14 10:42:16en
thesis.grantorVysoké učení technické v Brně. Fakulta stavební. Ústav pozemního stavitelstvícs
thesis.grantorVysoké učení technické v Brně. Fakulta stavební. Ústav technických zařízení budovcs
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