Air change rate in ventilated attics – reality and input for simulations

Eva B. Møller*, Martin Morelli, Thor Hansen

*Kontaktforfatter

Publikation: Bidrag til bog/antologi/rapport/konference proceedingKonferenceartikel i proceedingForskningpeer review

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Resumé

To remove moisture by ventilating constructions is a well-known strategy, used successfully in numerous facades and roofs. However, simulating ventilation is often difficult as convection in this case is in another dimension than what is usually in focus in 1D hygrothermal simulations. There are strategies for simulating ventilation in 1D programs assuming a fixed air change rate (ACH). Unfortunately, ACH in roofs highly depend on wind direction and speed, hence a constant rate is a gross simplification. The article describes a comparative study between simulations with a 1D hygrothermal simulation program (WUFI) and simulations with BSim, a program in which the indoor climate can be simulated in different zones, in this case the ventilated attic. Focus is the effect of ACH in the attic on temperature and relative humidity. Finally, measurements of ACH in attics of ten single-family houses are presented. These measurements show that average ACH measured over more than two weeks differ very much from house to house although the ventilation openings in all houses seemed to be in accordance with current guidelines. Even measurements of the same attic differ considerably from time to time. The paper discusses what implications this should have on simulations.
OriginalsprogEngelsk
Titel MATEC Web of Conferences : 4th Central European Symposium on Building Physics (CESBP 2019)
RedaktørerR. Černý, J. Kočí, V. Kočí
Antal sider6
Udgivelses stedPrague, Czech Republic
ForlagEDP Sciences
Publikationsdatosep. 2019
Sider1-6
Artikelnummer02073
DOI
StatusUdgivet - sep. 2019
BegivenhedCentral European Symposium on Building Physics 2019 - Faculty of Civil Engineering, CTU in Prague Thákurova 7 166 29 Prague, Czech Republic, Prague, Tjekkiet
Varighed: 2 sep. 20195 sep. 2019
Konferencens nummer: 4
https://www.cesbp2019.org/

Konference

KonferenceCentral European Symposium on Building Physics 2019
Nummer4
Lokation Faculty of Civil Engineering, CTU in Prague Thákurova 7 166 29 Prague, Czech Republic
LandTjekkiet
ByPrague
Periode02/09/201905/09/2019
Internetadresse
NavnMATEC Web of Conferences
Vol/bind282
ISSN2261-236X

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air
ventilation
simulation
roof
wind direction
rate
relative humidity
comparative study
wind velocity
convection
moisture
climate
programme
temperature

Citer dette

Møller, E. B., Morelli, M., & Hansen, T. (2019). Air change rate in ventilated attics – reality and input for simulations. I R. Černý, J. Kočí, & V. Kočí (red.), MATEC Web of Conferences: 4th Central European Symposium on Building Physics (CESBP 2019) (s. 1-6). [02073] Prague, Czech Republic: EDP Sciences. MATEC Web of Conferences, Bind. 282 https://doi.org/10.1051/matecconf/201928202073
Møller, Eva B. ; Morelli, Martin ; Hansen, Thor. / Air change rate in ventilated attics – reality and input for simulations. MATEC Web of Conferences: 4th Central European Symposium on Building Physics (CESBP 2019). red. / R. Černý ; J. Kočí ; V. Kočí. Prague, Czech Republic : EDP Sciences, 2019. s. 1-6 (MATEC Web of Conferences, Bind 282).
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title = "Air change rate in ventilated attics – reality and input for simulations",
abstract = "To remove moisture by ventilating constructions is a well-known strategy, used successfully in numerous facades and roofs. However, simulating ventilation is often difficult as convection in this case is in another dimension than what is usually in focus in 1D hygrothermal simulations. There are strategies for simulating ventilation in 1D programs assuming a fixed air change rate (ACH). Unfortunately, ACH in roofs highly depend on wind direction and speed, hence a constant rate is a gross simplification. The article describes a comparative study between simulations with a 1D hygrothermal simulation program (WUFI) and simulations with BSim, a program in which the indoor climate can be simulated in different zones, in this case the ventilated attic. Focus is the effect of ACH in the attic on temperature and relative humidity. Finally, measurements of ACH in attics of ten single-family houses are presented. These measurements show that average ACH measured over more than two weeks differ very much from house to house although the ventilation openings in all houses seemed to be in accordance with current guidelines. Even measurements of the same attic differ considerably from time to time. The paper discusses what implications this should have on simulations.",
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Møller, EB, Morelli, M & Hansen, T 2019, Air change rate in ventilated attics – reality and input for simulations. i R Černý, J Kočí & V Kočí (red), MATEC Web of Conferences: 4th Central European Symposium on Building Physics (CESBP 2019)., 02073, EDP Sciences, Prague, Czech Republic, MATEC Web of Conferences, bind 282, s. 1-6, Prague, Tjekkiet, 02/09/2019. https://doi.org/10.1051/matecconf/201928202073

Air change rate in ventilated attics – reality and input for simulations. / Møller, Eva B.; Morelli, Martin; Hansen, Thor.

MATEC Web of Conferences: 4th Central European Symposium on Building Physics (CESBP 2019). red. / R. Černý; J. Kočí; V. Kočí. Prague, Czech Republic : EDP Sciences, 2019. s. 1-6 02073 (MATEC Web of Conferences, Bind 282).

Publikation: Bidrag til bog/antologi/rapport/konference proceedingKonferenceartikel i proceedingForskningpeer review

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AU - Møller, Eva B.

AU - Morelli, Martin

AU - Hansen, Thor

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AB - To remove moisture by ventilating constructions is a well-known strategy, used successfully in numerous facades and roofs. However, simulating ventilation is often difficult as convection in this case is in another dimension than what is usually in focus in 1D hygrothermal simulations. There are strategies for simulating ventilation in 1D programs assuming a fixed air change rate (ACH). Unfortunately, ACH in roofs highly depend on wind direction and speed, hence a constant rate is a gross simplification. The article describes a comparative study between simulations with a 1D hygrothermal simulation program (WUFI) and simulations with BSim, a program in which the indoor climate can be simulated in different zones, in this case the ventilated attic. Focus is the effect of ACH in the attic on temperature and relative humidity. Finally, measurements of ACH in attics of ten single-family houses are presented. These measurements show that average ACH measured over more than two weeks differ very much from house to house although the ventilation openings in all houses seemed to be in accordance with current guidelines. Even measurements of the same attic differ considerably from time to time. The paper discusses what implications this should have on simulations.

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Møller EB, Morelli M, Hansen T. Air change rate in ventilated attics – reality and input for simulations. I Černý R, Kočí J, Kočí V, red., MATEC Web of Conferences: 4th Central European Symposium on Building Physics (CESBP 2019). Prague, Czech Republic: EDP Sciences. 2019. s. 1-6. 02073. (MATEC Web of Conferences, Bind 282). https://doi.org/10.1051/matecconf/201928202073