Numerical modelling of coupled heat, air and moisture transfer in building envelopes

Maliki, Mustapha; Laredj, Nadia; Missoum, Hanifi; Bendani, Karim; Naji, Hassane

doi:10.1051/meca/2015033

Cited by 5 publications

(6 citation statements)

References 26 publications

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“…For this, the working of the aforementioned model equations has been recently implemented by Maliki et al (2014Maliki et al ( , 2015 considering the 1D benchmark exercise #1. The latter arises from a series of benchmark cases from a work outcome of the EU-initiated project for standardization of heat, air and moisture calculation methods (European project known as HAMSTAD-WP2) (Hagentoft et al 2004;Hagentoft 2002).…”

Section: Numerical Handling Of the Two-dimensional Casementioning

confidence: 99%

Two-Dimensional Transient Modeling of Energy and Mass Transfer in Porous Building Components using COMSOL Multiphysics

Maliki¹,

Laredj²,

Bendani³

et al. 2017

JAFM

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This paper reports on a transient heat, air and moisture transfer (HAM) model. The governing partialdifferential equations are simultaneously solved for temperature and capillary pressure through multi-layered porous media, including the non-linear transfer and storage properties of materials. Using partial differential equations functions, some thermo-physical properties of porous media are converted into coefficients depending on temperature and capillary pressure. Major features of the model are multi-dimensional and transient coupling of heat, air and moisture transport. The coupled equations are solved using the COMSOL Multiphysics time-dependent solver. This solver enables HAM (Heat, Air, Moisture) modeling in porous media. Besides, the good agreements obtained with a 2D benchmark suggest that the model can be used to assess the hygrothermal performance of building envelope components. This paper concludes that the total heat flux in the insulated wall represents only the quarter of that crossing the uninsulated concrete roof. On the other hand, the concrete having the lowest water vapour permeability of all used materials allows maintaining the vapour pressure levels close to the initial value (10 3 Pa). This induces a situation of interstitial condensation within the concrete of the roof. Being able to evaluate the hygrothermal behaviour, the proposed model may turn out to be a valuable tool to solve other building problems.

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Section: Numerical Handling Of the Two-dimensional Casementioning

confidence: 99%

Two-Dimensional Transient Modeling of Energy and Mass Transfer in Porous Building Components using COMSOL Multiphysics

Maliki¹,

Laredj²,

Bendani³

et al. 2017

JAFM

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“…Mechanical ventilation is the most significant factor affecting indoor humidity [2]. State-of-the-art methods typically use physics-based models [3][4][5][6] to investigate the nonlinear relationship between ventilation rate and indoor humidity. However, certain factors, particularly the moisture buffering effects of building materials, can be challenging to account for in physical models [7].…”

Section: Introductionmentioning

confidence: 99%

Performance Comparison of Indoor Humidity Modeling: A Novel Hybrid Model vs. the Simplified Calculation Model by EN ISO 13788

Lu,

Lü,

Salonen

2023

J. Phys.: Conf. Ser.

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Ventilation is essential for maintaining indoor air quality and human comfort, particularly in buildings with mechanical ventilation systems. However, modeling the complex relationship between ventilation rate and measurable indoor environmental parameters, such as humidity, poses significant challenges. Current methods for modeling this relationship are often inefficient. For example, data-driven models frequently require sufficient information on ventilation, which may not be available for constant air volume (CAV) systems. On the other hand, simulation programs can be time-consuming and require expert engagement. In this study, we present two simplified calculation models, including a hybrid model developed by the authors, and a well-known model introduced by EN ISO 13788. We compare their performance in evaluating the impact of ventilation rate on indoor humidity. The hybrid model uses a novel analytical method to upgrade a single-input regression model (which considers only outdoor humidity as input) to enable the evaluation of indoor humidity based on both outdoor humidity and ventilation rate. We used the commercial TRNSYS program to model two scenarios: increasing the reference ventilation rate and decreasing the reference ventilation rate. The results showed that both models matched TRNSYS simulations with satisfactory accuracies, but the hybrid model demonstrated superior performance to the EN ISO 13788 model in both scenarios. The hybrid model’s higher accuracy and hybrid features make it better suited for big data analysis and field studies.

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“…The aforementioned HAM simulation tools are used to undertake detailed numerical simulations to understand the moisture response of materials and components to their imposed boundary conditions. As well, all have been used in various projects within NRC's Facade Systems and Products (FSP) group and have been properly validated through HAMSTAD Benchmarking Exercises or against experimental data (Cornick, 2006;Hagentoft et al, 2004;Hagerstedt and Arfvidsson, 2010;Knarud and Geving, 2015;Maliki et al, 2014;Maref et al, 2003;Mundt-Petersen and Harderup, 2013;Sontag et al, 2013). However, there are some fundamental differences amongst them that, depending on the boundary conditions, the intent of the simulations or the problem that needs to be solved, may lead to different results.…”

Section: Introductionmentioning

confidence: 99%

A comparison of hygrothermal simulation results derived from four simulation tools

Defo

Lacasse

Laouadi

2021

Journal of Building Physics

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The objective of this work was to compare the hygrothermal responses and the moisture performance of four wood-frame walls as predicted by four hygrothermal (HAM) simulation tools, namely: DELPHIN, WUFI, hygIRC and COMSOL. The four wall systems differ only in their cladding type; these were fibreboard, vinyl, stucco and brick. Three Canadian cities having different climates were selected for simulations: Ottawa, Ontario; Vancouver, British Columbia and Calgary, Alberta. In each city, simulations were run for 2 years. Temperature and relative humidity of the outer layer of OSB sheathing were compared amongst the four simulation tools. The mould growth index on the outer layer of the OSB sheathing was used to compare the moisture performance predicted by the respective hygrothermal simulation tools. Temperature profiles of the outer layer of the OSB sheathing were all in good agreement for the four HAM tools in the three locations. For relative humidity, the highest discrepancies amongst the four tools were found with stucco cladding where differences as high as 20% could be found from time to time. Mould growth indices predicted by the four HAM tools were similar in some cases but different in other cases. The discrepancies amongst the different HAM tools were likely related to: the material property processing, how the quantity of wind-driven rain absorbed at the cladding surface is computed and some implementation details. Despite these discrepancies, The tools generally yielded consistent results and could be used for comparing the impacts of different designs on the risk of premature deterioration, as well as for evaluating the relative effects of climate change on a given wall assembly design.

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Numerical modelling of coupled heat, air and moisture transfer in building envelopes

Cited by 5 publications

References 26 publications

Two-Dimensional Transient Modeling of Energy and Mass Transfer in Porous Building Components using COMSOL Multiphysics

Two-Dimensional Transient Modeling of Energy and Mass Transfer in Porous Building Components using COMSOL Multiphysics

Performance Comparison of Indoor Humidity Modeling: A Novel Hybrid Model vs. the Simplified Calculation Model by EN ISO 13788

A comparison of hygrothermal simulation results derived from four simulation tools

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