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ŠIKULA, O. MOHELNÍKOVÁ, J. PLÁŠEK, J.
Originální název
Thermal Analysis of Light Pipes for Insulated Flat Roofs
Typ
článek v časopise ve Web of Science, Jimp
Jazyk
angličtina
Originální abstrakt
Light pipes transmit daylight into building interiors. Their installation into thermally insulated roofs of low energy buildings can be a problem because of thermal bridges and condensation problems. This article is focused on a CFD simulation thermal analysis that include four variations of light pipes with a segment of a flat roof. Common light pipes with a hollow light guiding tube were compared to special light pipes containing an additional glass unit located inside the tube. The additional glass units increase thermal resistance and reduce condensation risks of the light guiding systems. The light pipes were compared in two different simulation models run in ANSYS Fluent software and the CalA program. Temperature profiles and air flow patterns of the cross sectional profiles of the light pipes served to determine the total heat transmittance and heat losses of the studied light pipes installed in a segment of a thermally insulated flat roof. The paper compares simplified 2D rotational-symmetrical numerical model based on the thermal diffusion equation with the complex 3D CFD numerical simulation. The results confirm that the simplified 2D numerical model is suitable for the thermal evaluation of the light pipes containing an additional glass unit, too. The additional glass unit with the triple glass improves thermal resistance up to 88% in case of light pipe with diameter 600 mm and reduces optical transmittance to 28%.
Klíčová slova
Heat transfer; CFD simulation; Tubular light guide; Thermal bridge; Water vapor condensation.
Autoři
ŠIKULA, O.; MOHELNÍKOVÁ, J.; PLÁŠEK, J.
Rok RIV
2014
Vydáno
22. 10. 2014
Nakladatel
Elsevier B.V.
Místo
Amsterdam
ISSN
0378-7788
Periodikum
ENERGY AND BUILDINGS
Ročník
Číslo
85
Stát
Švýcarská konfederace
Strany od
436
Strany do
444
Strany počet
9
URL
http://www.sciencedirect.com/science/article/pii/S0378778814007816#
Plný text v Digitální knihovně
http://hdl.handle.net/11012/69289
BibTex
@article{BUT109707, author="Ondřej {Šikula} and Jitka {Mohelníková} and Josef {Plášek}", title="Thermal Analysis of Light Pipes for Insulated Flat Roofs", journal="ENERGY AND BUILDINGS", year="2014", volume="2014", number="85", pages="436--444", doi="10.1016/j.enbuild.2014.09.044", issn="0378-7788", url="http://www.sciencedirect.com/science/article/pii/S0378778814007816#" }