Hygrothermal Modeling of Masonry with Interior Insulation Retrofit - Perspectives on hygrothermal performance and modeling-uncertainty
Doctoral thesis
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https://hdl.handle.net/11250/3115856Utgivelsesdato
2024Metadata
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Sammendrag
Energy retrofit of existing buildings is mainly an endeavor to reduce energy consumption. Interior insulation retrofit of masonry falls among retrofit measures in this regard. However, interior insulation of masonry may give rise to hygrothermal risks in the structure. Thus, hygrothermal analysis of solutions for such retrofit becomes paramount. Such analysis often involves hygrothermal simulations of models that represent the retrofit scenario. Unfortunately, analysis of this kind can be complex and often suffers from lack of information, like limited access to the material properties involved, or it suffers from inaccurate understanding of the acting moisture transfer mechanisms. Uncertainties thus exist that practitioners should be aware of.
The objective of this thesis is to provide a contribution to modeling techniques and to provide an insight that highlights modeling uncertainty. This with a focus on modeling bare brick masonry exposed to driving rain in the context of interior insulation retrofit.
The work spans small- and large-scale experiments, analytical work on material property modeling methods, and hygrothermal modeling and simulation. In the experiment work, a focus is given moisture absorption along the brick-mortar interface, which is an important aspect of rain absorption of bare brick masonry. The information gathered on such absorption is further investigated by hygrothermal simulation.
The work includes establishing a hygrothermal model for 2D and 3D analysis, where different parameters and modeling choices are investigated. A 3D analysis is of particular interest regarding beam ends embedded in the masonry, a detail vulnerable to moisture damage in interior insulation retrofitting of masonry.
A smart vapor barrier (SVB), which provides an inward drying potential during warm weather, while preventing interstitial condensation during cold weather, is given special attention since little data has previously been gathered on the performance of SVB as a measure in combination with interior insulated masonry.
Simplified modeling of hydraulic conductivity (liquid permeability) is explored to ease engineering applicability through prediction based on the capillary absorption coefficient and retention curve. This is done in the framework of a bundle of tubes model that is supplemented with a liquid film model, with the latter covering surface diffusion.
A large-scale laboratory experiment, including varying configurations of interior insulated masonry wall structures, is presented, and assessed for performance by the varying of parameters. In addition, it provides a scenario with accompanying performance results with which to compare hygrothermal simulations against, for a check of realism of simulation results.
Består av
Paper 1: Knarud, Jon Ivar Belghaug; Kvande, Tore; Geving, Stig. Experimental investigation of capillary absorption along mortar-brick interface plane. I: PROCEEDINGS OF THE CESBP Central European Symposium on Building Physics AND BauSIM 2016. Fraunhofer IRB Verlag 2016 ISBN 978‐3‐8167‐9798‐2.Paper 2: Knarud, Jon Ivar Belghaug; Geving, Stig; Kvande, Tore. Moisture performance of interior insulated brick wall segments subjected to wetting and drying – A laboratory investigation. Building and Environment 2021. Published by Elsevier Ltd. This is an open access article under the CC BY license. Available at: http://dx.doi.org/10.1016/j.buildenv.2020.107488
Paper 3: Knarud, Jon Ivar Belghaug; Geving, Stig. Implementation and benchmarking of a 3D hygrothermal model in the COMSOL Multiphysics software. Energy Procedia 2015 ;Volum 78. s. 3440-3445. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license. Available at: http://dx.doi.org/10.1016/j.egypro.2015.12.327
Paper 4: Knarud, Jon Ivar Belghaug; Geving, Stig. Comparative study of hygrothermal simulations of a masonry wall FILLIN. Energy Procedia 2017 ;Volum 132. s. 771-776. . Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license. Available at: http://dx.doi.org/10.1016/j.egypro.2017.10.027
Paper 5: Knarud, Jon Ivar Belghaug; Kvande, Tore; Geving, Stig. Modelling hydraulic conductivity for porous building materials based on a prediction of capillary conductivity at capillary saturation. International Journal of Heat and Mass Transfer 2021 ;Volum 186. s. - Published by Elsevier Ltd. This is an open access article under the CC BY license. Available at: http://dx.doi.org/10.1016/j.ijheatmasstransfer.2021.122457
Paper 6: Knarud, Jon Ivar Belghaug; Kvande, Tore; Geving, Stig. Hygrothermal Simulation of Interior Insulated Brick Wall—Perspectives on Uncertainty and Sensitivity. Buildings 2023 ;Volum 13.(7) s. - Published by MDPI. This is an open access article under the CC BY license. Available at: http://dx.doi.org/10.3390/buildings13071701