Optimized mitigation of heat loss by avoiding wall-to-floor thermal bridges in reinforced concrete buildings

Jiang, Lu; Xue, Yucong; Wang, Zhi; Fan, Yifan

doi:10.1016/j.jobe.2020.101214

Cited by 17 publications

(10 citation statements)

References 26 publications

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“…Simulated results show that moisture gathers at the interface between WFTB and the main part of walls, which leads to (1) the heat losses from the interface may have a sharp rise due to the increase of thermal conductivity and the bimodal phenomenon of temperature [2,3] , and (2) the vapour in the circled area (see Figure 2(a)) has a high risk of condensation when the ambient temperature has a sudden drop. It is also found that the moisture content at the interior surface of WFTB is relatively less than the surrounding area during every season.…”

Section: Discussionmentioning

confidence: 99%

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Moisture distribution in wall-to-floor thermal bridges under the analysis of coupled heat and moisture transfer

Xue

Fan

2021

Moisture Distribution in Wall-to-Floor Thermal Bridges Under the Analysis of Coupled Heat and Moisture Transfer

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A little change of moisture content in thermal bridges (TBs) can lead to a big difference in heat and moisture transfer here as heat transfers more violently at TBs than the main part of walls. We aimed to (1) reveal the moisture distribution in the typical TB (i.e., wall-to-floor thermal bridge, WFTB) and its surrounding area, and (2) find high-risk areas for condensation. The transient numerical simulations lasted for two years were performed to model the moisture distribution. Simulated results show that the moisture distribution presents significant seasonal and spatial difference due to the WFTB, and the interface between WFTBs and the main part of walls has likelihood of condensation in winter.Peer-review under the responsibility of the organizing committee of the ICMB21.

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Section: Discussionmentioning

confidence: 99%

“…Reinforced concrete is usually adopted to cast such structures due to its satisfactory mechanical property. However, the high thermal conductivity of reinforced concrete makes the frame structure TBs [2,3] . The wall-to-floor thermal bridge (WFTB) occupies the largest area with the most massive heat flux.…”

Section: Introduction/backgroundmentioning

confidence: 99%

Moisture distribution in wall-to-floor thermal bridges under the analysis of coupled heat and moisture transfer

Xue

Fan

2021

Moisture Distribution in Wall-to-Floor Thermal Bridges Under the Analysis of Coupled Heat and Moisture Transfer

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“…Furthermore, the heat loss caused by the thermal bridge in winter leads to a decrease in the temperature of the inner surface and an increase in condensation [11]. In apartment buildings, windows, doors, and junctions are weak areas that can form thermal bridges [12][13][14]. The balcony slab is the second-largest component of the thermal bridge in buildings, except for windows and doors.…”

Section: Introductionmentioning

confidence: 99%

Performance Evaluation of Thermal Bridge Reduction Method for Balcony in Apartment Buildings

2022

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Most apartment buildings in South Korea use internal insulation systems to reduce building energy demand. However, thermal bridges such as balcony slabs in apartment buildings still lead to significant heat loss in winter, because the internal insulation system is not continuous in the balcony slab structure, and floor heating systems are commonly used in residential buildings. Therefore, this study investigates two types of thermal break elements, namely thermal break (TB) and thermal break-fiber glass reinforced polymer (TB-GFRP), to improve the thermal resistance of a balcony thermal bridge. To understand the effects of balcony thermal bridges with and without thermal break elements, the linear thermal transmittances of different balcony thermal bridges were analyzed using Physibel simulations. Then, the heating demand of a model apartment under varying thermal bridge conditions was evaluated using TRNSYS simulations. To understand the effect of insulation systems on heat loss through a balcony thermal bridge, apartments with internal and external insulation systems were studied. Whether the apartment was heating was also considered in the thermal transmittance analysis. Thus, the linear thermal transmittance of the thermal bridges with thermal break elements was reduced by more than 60%, and the heating energy demands were reduced by more than 8%.

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“…Based on the above research gaps, the objective of this study is to establish a model which is capable of simulating the coupled heat and moisture transfer (denoted as HAMT model) in a typical thermal bridge. The wall-to-floor thermal bridge (WFTB) occupies the largest area with the most massive heat flux [8,9]. Therefore, the WFTB is employed as the object in our study to (1) reveal the moisture distribution, and (2) find high-risk areas for mould growth.…”

Section: Introductionmentioning

confidence: 99%

The moisture distribution in wall-to-floor thermal bridges and its influence on mould growth

Xue

Fan

2022

Preprint

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Moisture in the building envelopes increase the energy consumption of buildings and induce mould growth, which may be amplified within the area of thermal bridges due to their different hygrothermal properties and complex structures. In this study, we aimed to (1) reveal the moisture distribution in the typical thermal bridges (i.e., wall-to-floor thermal bridge, WFTB) and its surrounding area, and (2) investigate the mould growth in the building envelope that includes both WFTB and the main part of the wall. The transient numerical simulations that lasted for five years were performed to model the moisture distribution. Simulated results indicate that the moisture distribution presents significant seasonal and spatial differences due to the WFTB. The areas where moisture accumulates have a higher risk of mould growth. The thermal insulation layer laid on the exterior surface of WFTB can reduce the overall humidity while uneven moisture distribution, which may promote mould growth and water vapour condensation.

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Optimized mitigation of heat loss by avoiding wall-to-floor thermal bridges in reinforced concrete buildings

Cited by 17 publications

References 26 publications

Moisture distribution in wall-to-floor thermal bridges under the analysis of coupled heat and moisture transfer

Moisture distribution in wall-to-floor thermal bridges under the analysis of coupled heat and moisture transfer

Performance Evaluation of Thermal Bridge Reduction Method for Balcony in Apartment Buildings

The moisture distribution in wall-to-floor thermal bridges and its influence on mould growth

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