Heat and Moisture Transport and Storage Parameters of Bricks Affected by the Environment

Kočí, Václav; Čáchová, Monika; Koňáková, Dana; Vejmelková, Eva; Jerman, Miloš; Keppert, Martin; Maděra, Jiří; Černý, Robert

doi:10.1007/s10765-018-2383-2

Cited by 15 publications

(4 citation statements)

References 28 publications

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“…The material characteristics of the studied materials were determined following the procedure described by Černý (2013). The results are summarized in Table 2 Kočí et al, 2017;Kočí et al, 2018b). The meaning of used symbols is as follows: ρ -bulk density (kg•m -3 ), ψ -total porosity (%), µ -water vapor diffusion resistance factor (measured using dry cup and wet cup methods) (-), κ app -apparent moisture diffusivity (m 2 •s -1 ), c -specific heat capacity (in dry and water saturated state) (J•kg -1 •K -1 ), λ -thermal conductivity (in dry and water saturated state) (W•m -1 •K -1 ).…”

Section: Materials and Methods Materialsmentioning

confidence: 99%

Assessment of Cumulative Damage of Selected Building Envelopes Exposed to Various Environmental Effects

Kočí¹,

Maděra²,

Černý³

2018

Healthy, Intelligent and Resilient Buildings and Urban Environments

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Hygrothermal performance of building envelopes based on three different building materials (solid brick, high performance concrete, aerated autoclaved concrete) is assessed under climatic conditions of Prague and Atlantic City. Main objective of the paper is to evaluate the influence of cumulative damage, which was induced by means of natural weathering in 2012-2015 period, on the long-term performance. The performance is assessed using various measures, namely time-of-wetness function, number of freeze/thaw cycles, and annual amount of energy transmitted through the envelope. The results show that thermal performance of the envelopes gets mostly better after weathering as the annual amount of energy is decreased by ~3.5% in average. On the other hand, time-of-wetness function and number of freeze/thaw cycles increase by ~24.1% and ~22.0%, respectively. Based on the results summary it can be concluded, that cumulative damage of materials has an indisputable influence on the hygrothermal performance of building envelopes which might be either negative or positive. A detailed computational assessment is therefore necessary, incorporating not only reference, but also weather-affected material properties.

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Section: Materials and Methods Materialsmentioning

confidence: 99%

Assessment of Cumulative Damage of Selected Building Envelopes Exposed to Various Environmental Effects

Kočí¹,

Maděra²,

Černý³

2018

Healthy, Intelligent and Resilient Buildings and Urban Environments

Self Cite

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“…A numerical investigation of moisture and heat transmission was described [ 23 ]. The impact of ouside surroundings was evaluated [ 24 ]. The solutions demonstrated enhancements to the yearly energy balances.…”

Section: Introductionmentioning

confidence: 99%

Numerical computation of heat transfer, moisture transport and thermal comfort through walls of buildings made of concrete material in the city of Douala, Cameroon: An ab initio investigation

Moyou,

Njifenjou,

Tiam Kapen

et al. 2024

Heliyon

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“…The aging of materials from decay or damage can also change material properties over time. This has been illustrated by several authors regarding micro-scale cracks, freeze-thaw effects and mortar damage impacting absorption (Kočí et al, 2018;Li et al, 2018;Roels et al, 2003;Rouchier, 2012;Smyl et al, 2016).…”

Section: Materials Propertiesmentioning

confidence: 86%

“…These effects are often not considered in hygrothermal simulations of masonry (Kersten & van Schnijdel, 2013;Kočí et al, 2018;Nagy & Tóth, 2016). included (Harrestrup & Svendsen, 2016;Iodice et al, 2016;Morelli & Svendsen, 2013).…”

Section: Heat Transfer and U-valuesmentioning

confidence: 99%

Evaluating Uncertainty in Hygrothermal Modelling of Heritage Masonry Buildings

Gutland¹

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Hygrothermal models are important tools for assessing durability risks in building envelopes, such as biological growth (mould and wood rot fungi), corrosion and freeze-thaw action in masonry. Hygrothermal modelling of mass masonry wall assemblies are known to have numerous weaknesses and gaps in our understanding. First, there are significant uncertainties relating to model inputs including material properties and boundary conditions. Second, it is difficult to calibrate model results against data measured in the field. Third, two and threedimensional interactions between adjacent materials in masonry assemblies are poorly understood and are rarely modelled in practice. And fourth, geometric irregularities, imperfections and the effects of decay are rarely considered by modellers. Combined, these uncertainties can lead to reduced confidence in the model's conclusion and alter our opinions on the durability risks and whether retrofits such as interior insulation are appropriate or not. This doctoral thesis examines how uncertainty factors into hygrothermal modelling of heritage masonry, and how it can be reduced, and or, acknowledged in practice. This is demonstrated using a combination of simulation studies and on-site monitoring work. Three peer-reviewed papers which demonstrate examples of uncertainty in hygrothermal modelling are presented.The first paper presents a methodology for integrating calibrated hygrothermal and energy models of the Southwest Tower of the East Block for the purpose of assessing durability. This project consisted of in-situ monitoring of the masonry and ii interior climate of the Southwest Tower for over a year. The calibrated energy model was used as basis for estimating the net benefit of interior climate retrofits on the durability of the masonry. The calibrated hygrothermal model was not as successful, but the lessons learned were transferable to the third paper.The second paper examines the imperfect nature of the mortar-unit interface in masonry and how this affects moisture transfer into and out of the wall. Simulations showed that modelling this interface explicitly as a fracture will increase water absorption during wetting periods, but also help slightly with releasing moisture under drying conditions.The third paper examines the uncertainty in geometry and construction of the rubble core walls of the East Block. The wall's stack pattern is highly irregular and the core of the walls are known to have significant levels of voids which can act like insulating layers, or act as mini-rainscreens slowing moisture transfer into the wall. A Python script was developed to stochastically-generate sections of walls with and without voids. A significant variation in state variables, and heat and moisture fluxes was found between stochastically generated geometries in the mortar joints and in the rubble core. This variation increased with the number of voids.Overall, this research contributes to efforts make hygrothermal modelling of masonry more accurate and more intuitive for practiti...

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Heat and Moisture Transport and Storage Parameters of Bricks Affected by the Environment

Cited by 15 publications

References 28 publications

Assessment of Cumulative Damage of Selected Building Envelopes Exposed to Various Environmental Effects

Assessment of Cumulative Damage of Selected Building Envelopes Exposed to Various Environmental Effects

Numerical computation of heat transfer, moisture transport and thermal comfort through walls of buildings made of concrete material in the city of Douala, Cameroon: An ab initio investigation

Evaluating Uncertainty in Hygrothermal Modelling of Heritage Masonry Buildings

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