Publication detail

Thermal CFD Analysis of Tubular Light Guides

ŠIKULA, O. MOHELNÍKOVÁ, J. PLÁŠEK, J.

Original Title

Thermal CFD Analysis of Tubular Light Guides

Type

journal article in Web of Science

Language

English

Original Abstract

Tubular 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.

Keywords

computer simulation; ANSYS Fluent; CFD model; tubular light guides; thermal bridges; temperature distribution; air flow; thermal radiation; discrete transfer radiation model

Authors

ŠIKULA, O.; MOHELNÍKOVÁ, J.; PLÁŠEK, J.

RIV year

2013

Released

3. 12. 2013

Publisher

MDPI

Location

Basel, Switzerland

ISBN

1996-1073

Periodical

ENERGIES

Year of study

6

Number

12

State

Swiss Confederation

Pages from

6304

Pages to

6321

Pages count

18

URL

http://www.mdpi.com/1996-1073/6/12/6304

Full text in the Digital Library

http://hdl.handle.net/11012/69288

BibTex

@article{BUT103274,
  author="Ondřej {Šikula} and Jitka {Mohelníková} and Josef {Plášek}",
  title="Thermal CFD Analysis of Tubular Light Guides",
  journal="ENERGIES",
  year="2013",
  volume="6",
  number="12",
  pages="6304--6321",
  doi="10.3390/en6126304",
  issn="1996-1073",
  url="http://www.mdpi.com/1996-1073/6/12/6304"
}