Effect of moisture migration and phase change on effective thermal conductivity of porous building materials

Wang, Yingying; Ma, Chao; Liu, Yanfeng; Wang, Dengjia; Liu, Jiaping

doi:10.1016/j.ijheatmasstransfer.2018.04.062

Cited by 42 publications

(15 citation statements)

References 37 publications

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“…Moreover, it is the porosity that determines the gas and moisture permeability of a material [ 15 ]. The predominance of channel porosity can be accompanied by moisture migration in building materials, which can lead to undesirable consequences [ 16 , 17 ]. Excess moisture on the wall can even unpredictably affect the operation of heating system devices [ 18 , 19 ].…”

Section: Introductionmentioning

confidence: 99%

Improving the Efficiency of Non-Stationary Climate Control in Buildings with a Non-Constant Stay of People by Using Porous Materials

Shkarovskiy

Mamedov

2021

Materials

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This article presents the results of experimental research on the non-stationary management of the internal climate of buildings with a non-constant stay of people. During the absence of people, a significant drop in air temperature and corresponding energy conservation in heating is possible. The effectiveness of porous building materials is shown, provided that the appropriate characteristics are selected. Daily fluctuations in the outside temperature are completely extinguished by a layer of foam polystyrene insulation. The absence of channel porosity in the structural material of the wall is a guarantee of the stability of its thermal and humidity regime. This, in turn, prevents the development of mold and mildew.

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Section: Introductionmentioning

confidence: 99%

Improving the Efficiency of Non-Stationary Climate Control in Buildings with a Non-Constant Stay of People by Using Porous Materials

Shkarovskiy

Mamedov

2021

Materials

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“…1) Because of this characteristic, PCM plays an important role in energy conservation and emission reduction. 2,3) Up to now, PCM have showed great application potential in many fields, such as solar energy utilization, [4][5][6] intelligent building, [7][8][9] waste heat recovery, [10][11][12] thermal management [13][14][15] and so on. In particular, phase change materials have great application value in waste heat recovery.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Heat Transfer Enhancement of Phase Change Material using Embedded Oscillating Heat Pipe for Thermal Energy Storage

Liu

Jiang

et al. 2020

ISIJ Int.

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“…You et al (2017) computed quantitatively the effect of outdoor air temperature, humidity ratio and air infiltration in the walls, showing that these are all determining factors for moisture condensation. Wang et al (2018) then showed that the additional thermal conductivity of the walls, generated by the moisture migration and phase change in the envelope, depends strongly on the thermal gradient but very weakly on the pressure difference indoor–outdoor.…”

Section: Introductionmentioning

confidence: 99%

Positive pressure effect on moisture performance in a school building

Ferrantelli

Vornanen-Winqvist²,

Mattila³

et al. 2019

Journal of Building Physics

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Moisture excess in buildings constitutes a complex problem affecting indoor air quality, energy consumption and the lifetime of the building envelope. We investigate the effect on moisture transfer in structures as a positive pressure is applied inside the enclosure. It is found that, contrary to established belief, the positive pressure does not induce any negative effects on the structures’ moisture content in normally ventilated classrooms, even with high occupancy. Our case study consists of a school building in Finland, subject to temperature and relative humidity measurements after a small (5–7 Pa) positive pressure was realized through ventilation control. We first address analytically the moisture excess generated inside the classrooms for 14 days, using dynamical balance equations that account for both ventilation effects and occupants’ moisture release in the environment. It is found that the average moisture excess is very small, largely below 1 g/m3, even for ventilation rates that are half the design value. We also examine the moisture performance of the envelope, by addressing the moisture migration at upper and lower joints of the external walls for both measured and design values of the indoor absolute humidity (AH). A coupled numerical model of diffusion and convection shows that moisture accumulation in the envelope and the according stresses are negligible for any realistic AH values. This result is in agreement with field measurements at the school. In conclusion, it seems that applying a small overpressure in a well-ventilated school building during a standard service period resulted in no accumulation inside the external walls, even at high occupancy and with low ventilation. Remarkably, it slightly dried out the moisture content in structures under actual occupancy conditions. The positive pressure has accordingly no negative effects on moisture performance, and is capable to guarantee a good indoor air quality as well.

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Effect of moisture migration and phase change on effective thermal conductivity of porous building materials

Cited by 42 publications

References 37 publications

Improving the Efficiency of Non-Stationary Climate Control in Buildings with a Non-Constant Stay of People by Using Porous Materials

Improving the Efficiency of Non-Stationary Climate Control in Buildings with a Non-Constant Stay of People by Using Porous Materials

Experimental Study on Heat Transfer Enhancement of Phase Change Material using Embedded Oscillating Heat Pipe for Thermal Energy Storage

Positive pressure effect on moisture performance in a school building

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