Combined effects of sorption hysteresis and its temperature dependency on wood materials and building enclosures – Part I: Measurements for model validation

Zhang, Xiaobo; Zillig, Wolfgang; Künzel, Hartwig M.; Mitterer, Christoph; Zhang, Xu

doi:10.1016/j.buildenv.2016.06.025

Cited by 25 publications

(11 citation statements)

References 19 publications

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“…Hygroscopic materials, such as foam materials, have the ability to adsorb and desorb moisture with variations in surrounding conditions. 45 Figure 10 shows the sorption measurement sequences of the samples under 33, 55, and 75% humidity levels. When the measurement was finished, the equilibrium moisture content by mass (g/g) was measured using eq 1 where m 0 and m a are the masses of the sample under the initial dry and controlled relative humidity environments, respectively.…”

Section: Results and Discussionmentioning

confidence: 99%

Comprehensive Investigation of the Behavior of Polyurethane Foams Based on Conventional Polyol and Oligo-Ester-Ether-Diol from Waste Poly(ethylene terephthalate): Fireproof Performances, Thermal Stabilities, and Physicomechanical Properties

Pham

Nguyen

et al. 2020

ACS Omega

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The chemical recycling of postconsumer poly-(ethylene terephthalate) (PET) bottles to produce highly thermally stable polyurethane foam (r-PUF) with excellent flame-retardant (FR) performance could be applied on an industrial scale to create a sustainable recycling industry. The advantage of oligo-ester-ether-diol obtained from waste PET glycolysis is its application in r-PUF, generating a durable foam with excellent fire resistance at rather low loadings of phosphorus− nitrogen FRs (P−N FRs), especially in high moisture environments. Compared to polyurethane foam from commercial polyol (c-PUF), r-PUF is notably more thermally stable and efficient in terms of flame retardancy, even without adding FRs. By incorporating 15 php diammonium phosphate (DAP) as a P−N FR, r-PUF/DAP self-extinguished 5 s after the removal of the 2nd flame application with a limited oxygen index value of 24%. However, for c-PUF, a much higher DAP (30 php) loading did not exhibit any rating in the vertical burning test. The aromatic moiety in the oligo-ester-ether-diol structure strongly enhanced the compressive strength and thermal stability. The positive outcomes of this study also confirmed that the r-PUF/DAP prepared from oligo-ester-ether-diol not only satisfied the fire safety requirements of polymer applications but also contained a high percentage of postconsumer PET, which could help reduce the amount of recycled polymer materials and improve waste management.

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Section: Results and Discussionmentioning

confidence: 99%

Comprehensive Investigation of the Behavior of Polyurethane Foams Based on Conventional Polyol and Oligo-Ester-Ether-Diol from Waste Poly(ethylene terephthalate): Fireproof Performances, Thermal Stabilities, and Physicomechanical Properties

Pham

Nguyen

et al. 2020

ACS Omega

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“…At the top of the sample x = 0 , Robin type boundary conditions are assumed for heat and vapor flows according to Eqs. (6) and (8). At the bottom of the sample x = L , the temperature is prescribed using measurements.…”

Section: Comparison Of Numerical Predictions With Experimental Observmentioning

confidence: 99%

“…In [7], the prediction of the durability risks of material are more accurate with hysteresis effects. In [8,9], the importance of hysteresis effects on mold growth on wood material is enhanced. Thus, the issue stems from including the hysteresis effects in the mathematical model describing the moisture content in the material.…”

Section: Introductionmentioning

confidence: 99%

Critical assessment of a new mathematical model for hysteresis effects on heat and mass transfer in porous building material

Berger

Busser

Colinart

et al. 2020

International Journal of Thermal Sciences

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The reliability of mathematical models for heat and mass transfer in building porous material is of capital importance. A reliable model permits to carry predictions of the physical phenomenon with sufficient confidence in the results. Among the physical phenomena, the hysteresis effects on moisture sorption and moisture capacity need to be integrated in the mathematical model of transfer. This article proposes to explore the use of an smooth Bang-Bang model to simulate the hysteresis effects coupled with heat and mass transfer in porous material. This model adds two supplementary differential equations to the two classical ones for heat and mass transfer. The solution of these equations ensures smooth transitions between the main sorption and desorption curves. Two parameters are required to control the speed of transition through the intermediary curves. After the mathematical description of the model, an efficient numerical model is proposed to compute the fields with accuracy and reduced computational efforts. It is based on the Du Fort-Frankel scheme for the heat and mass balance equations. For the hysteresis numerical model, an innovative implicit-explicit approach is proposed. Then, the predictions of the numerical model are compared with experimental observations from literature for two case studies. The first one corresponds to a slow cycle of adsorption and desorption while the second is based on a fast cycling case with alternative increase and decrease of moisture content. The comparisons highlight a very satisfactory agreement between the numerical predictions and the observations. In the last Section, the reliability and efficiency of the proposed model is investigated for long term simulation cases. The importance of considering hysteresis effects in the reliability of the predictions are enhanced by comparison with classical approaches from literature.

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“…In thermal calculations, the moisture content of materials plays a significant role in heat transfer. The thermal conductivity of the material will depend on the sorption moisture [1][2][3][4][5]. For this reason, the protective properties of the enclosing structures may decrease.…”

Section: Introductionmentioning

confidence: 99%

Study of the dependence of equilibrium sorption humidity of heat-insulating products on temperature

Petrov

Kupriyanov

2021

E3S Web Conf.

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The desiccator method for products like mineral wool has a low accuracy, which is due to the small mass of the samples and the uneven content of the binder between the samples. The standard method does not involve testing materials at different temperatures. However, the value of sorption moisture depends not only on the nature and structure of the material, but also on the temperature conditions. At the moment, the regularities of changes in the sorption moisture content of materials depending on the air temperature have been studied only in separate scientific works and do not cover the entire spectrum of modern building materials. The paper presents the results of a study of the sorption moisture content of modern mineral wool products at various temperatures above 0 ºС. The results show an increase in sorption humidity with decreasing temperature from 22 ºС to 0 ºС. The greatest increase in humidity occurs at values of relative air humidity in the range of 90–97 %. It is shown that the standard desiccator method for studying sorption moisture requires scientific development and increased control of test conditions with decreasing temperature.

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Combined effects of sorption hysteresis and its temperature dependency on wood materials and building enclosures – Part I: Measurements for model validation

Cited by 25 publications

References 19 publications

Comprehensive Investigation of the Behavior of Polyurethane Foams Based on Conventional Polyol and Oligo-Ester-Ether-Diol from Waste Poly(ethylene terephthalate): Fireproof Performances, Thermal Stabilities, and Physicomechanical Properties

Comprehensive Investigation of the Behavior of Polyurethane Foams Based on Conventional Polyol and Oligo-Ester-Ether-Diol from Waste Poly(ethylene terephthalate): Fireproof Performances, Thermal Stabilities, and Physicomechanical Properties

Critical assessment of a new mathematical model for hysteresis effects on heat and mass transfer in porous building material

Study of the dependence of equilibrium sorption humidity of heat-insulating products on temperature

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