Assessment of the validity of some common assumptions in hygrothermal modelling of earth based materials

L. Soudani; A. Fabbri; Jean-Claude Morel; M Woloszyn; P. A. Chabriac; H. Wong; A. C. Grillet

doi:10.1016/j.enbuild.2016.01.025

Assessment of the validity of some common assumptions in hygrothermal modelling of earth based materials

L. Soudani, A. Fabbri, Jean-Claude Morel, M Woloszyn, P. A. Chabriac, H. Wong, A. C. Grillet

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Abstract

The goal of this paper is to identify the effects of in-pore transport of liquid water and water vapor as well as phase changes on the hygrothermal behavior of earthen buildings. Indeed, one of the main assets used to promote these constructions is their role in moisture buffering hence temperature and relative-humidity quality controlling. However, there is no clear consensus yet concerning the impact of these phenomena on the global energy performance of the buildings. A coupled model is therefore proposed in this paper, based on heat and mass balances inside the earthen walls, in order to clarify this question. This model considers separately the kinematics of each phase (e.g. liquid water, vapor, dry air and solid matrix), in interaction with each other. It also takes into account the impact of pore water confinement on the liquid-to-vapor phase change, in particular on the resulting latent heat released or absorbed. The model is successfully compared to experimental results on instrumented full-scale rammed earth wall subjected to temperature cycles. It eventually allows identifying the singular hygrothermal behaviour of earth material by testing the range of applicability of the simplifying assumptions which are commonly made in function of the permeability of the tested material.

Original language	English
Pages (from-to)	498–511
Number of pages	14
Journal	Energy and Buildings
Volume	116
Early online date	21 Jan 2016
DOIs	https://doi.org/10.1016/j.enbuild.2016.01.025
Publication status	Published - 15 Mar 2016

Bibliographical note

NOTICE: this is the author’s version of a work that was accepted for publication in Energy and Buildings. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Energy and Buildings, [116, (2016)] DOI: 10.1016/j.enbuild.2016.01.025

© 2016, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/

Keywords

Heat and moisture transport
Hygrothermal modeling
Numerical simulation
Rammed earth
Adobe
Cob

Access to Document

10.1016/j.enbuild.2016.01.025

1-s2 0-S0378778816300251-mainAccepted author manuscript, 1.87 MBLicence: CC BY-NC-ND

Cite this

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title = "Assessment of the validity of some common assumptions in hygrothermal modelling of earth based materials",

abstract = "The goal of this paper is to identify the effects of in-pore transport of liquid water and water vapor as well as phase changes on the hygrothermal behavior of earthen buildings. Indeed, one of the main assets used to promote these constructions is their role in moisture buffering hence temperature and relative-humidity quality controlling. However, there is no clear consensus yet concerning the impact of these phenomena on the global energy performance of the buildings. A coupled model is therefore proposed in this paper, based on heat and mass balances inside the earthen walls, in order to clarify this question. This model considers separately the kinematics of each phase (e.g. liquid water, vapor, dry air and solid matrix), in interaction with each other. It also takes into account the impact of pore water confinement on the liquid-to-vapor phase change, in particular on the resulting latent heat released or absorbed. The model is successfully compared to experimental results on instrumented full-scale rammed earth wall subjected to temperature cycles. It eventually allows identifying the singular hygrothermal behaviour of earth material by testing the range of applicability of the simplifying assumptions which are commonly made in function of the permeability of the tested material. ",

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author = "L. Soudani and A. Fabbri and Jean-Claude Morel and M Woloszyn and Chabriac, {P. A.} and H. Wong and Grillet, {A. C.}",

note = "NOTICE: this is the author{\textquoteright}s version of a work that was accepted for publication in Energy and Buildings. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Energy and Buildings, [116, (2016)] DOI: 10.1016/j.enbuild.2016.01.025 {\textcopyright} 2016, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/",

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AU - Chabriac, P. A.

AU - Wong, H.

AU - Grillet, A. C.

N1 - NOTICE: this is the author’s version of a work that was accepted for publication in Energy and Buildings. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Energy and Buildings, [116, (2016)] DOI: 10.1016/j.enbuild.2016.01.025 © 2016, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/

PY - 2016/3/15

Y1 - 2016/3/15

N2 - The goal of this paper is to identify the effects of in-pore transport of liquid water and water vapor as well as phase changes on the hygrothermal behavior of earthen buildings. Indeed, one of the main assets used to promote these constructions is their role in moisture buffering hence temperature and relative-humidity quality controlling. However, there is no clear consensus yet concerning the impact of these phenomena on the global energy performance of the buildings. A coupled model is therefore proposed in this paper, based on heat and mass balances inside the earthen walls, in order to clarify this question. This model considers separately the kinematics of each phase (e.g. liquid water, vapor, dry air and solid matrix), in interaction with each other. It also takes into account the impact of pore water confinement on the liquid-to-vapor phase change, in particular on the resulting latent heat released or absorbed. The model is successfully compared to experimental results on instrumented full-scale rammed earth wall subjected to temperature cycles. It eventually allows identifying the singular hygrothermal behaviour of earth material by testing the range of applicability of the simplifying assumptions which are commonly made in function of the permeability of the tested material.

AB - The goal of this paper is to identify the effects of in-pore transport of liquid water and water vapor as well as phase changes on the hygrothermal behavior of earthen buildings. Indeed, one of the main assets used to promote these constructions is their role in moisture buffering hence temperature and relative-humidity quality controlling. However, there is no clear consensus yet concerning the impact of these phenomena on the global energy performance of the buildings. A coupled model is therefore proposed in this paper, based on heat and mass balances inside the earthen walls, in order to clarify this question. This model considers separately the kinematics of each phase (e.g. liquid water, vapor, dry air and solid matrix), in interaction with each other. It also takes into account the impact of pore water confinement on the liquid-to-vapor phase change, in particular on the resulting latent heat released or absorbed. The model is successfully compared to experimental results on instrumented full-scale rammed earth wall subjected to temperature cycles. It eventually allows identifying the singular hygrothermal behaviour of earth material by testing the range of applicability of the simplifying assumptions which are commonly made in function of the permeability of the tested material.

KW - Heat and moisture transport

KW - Hygrothermal modeling

KW - Numerical simulation

KW - Rammed earth

KW - Adobe

KW - Cob

U2 - 10.1016/j.enbuild.2016.01.025

DO - 10.1016/j.enbuild.2016.01.025

M3 - Article

SN - 0378-7788

SN - 1872-6178

VL - 116

SP - 498

EP - 511

JO - Energy and Buildings

JF - Energy and Buildings

ER -

Assessment of the validity of some common assumptions in hygrothermal modelling of earth based materials

Abstract

Bibliographical note

Keywords

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