Numerical study of time-dependent hygrothermal conditions in depressurized crawl space

Salo, Juha; Huttunen, Petteri; Vinha, Juha; Keskikuru, T.

doi:10.1007/s12273-018-0447-7

Cited by 4 publications

(3 citation statements)

References 15 publications

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“…In this study, the WUFI software was used to evaluate the simultaneous influence of humidity and temperature over thermal performance of green roof system including drainage layer of pozzolana and substrate. The WUFI software is capable of modeling the simultaneous moisture and temperature distribution through the depth of building materials (Azizkhani and Haberl 2020;Nore et al 2017;Salo et al 2018). Table 1 presents the characteristics of green roof's layers.…”

Section: Wufi Implementationmentioning

confidence: 99%

Simulation of humidity and temperature distribution in green roof with pozzolana as drainage layer: Influence of outdoor seasonal weather conditions and internal ceiling temperature

Kazemi

Courard

2021

Science and Technology for the Built Environment

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The outdoor seasonal weather conditions can influence the insulation performance of extensive green roof. In addition, the thermal behavior of extensive green roof can be affected by the thickness of its layers including substrate and drainage layer. On the other hand, the replacement of polyethylene modular panel with porous aggregates as drainage layer can affect the water retention capacity of green roof. Therefore, in this study, the green roofs with pozzolana (porous volcanic gravel) as drainage layer under constant and variable inside temperatures were modeled and subjected to the weather conditions of winter and summer to assess the humidity and temperature variations in the depth of the systems. The results showed that there was a decrease in temperature through the depth of the green roof system for the winter period, while the reverse occurred for the relative humidity. During the winter period, the green roof model with the 10-cm substrate and 8-cm pozzolana was recommended to be used.However, the model with the 8-cm substrate and 6-cm drainage layer had the best insulation performance, particularly for the summer period. Moreover, the internal ceiling temperature fluctuation of system under variable inside temperature was higher than that under constant inside temperature.

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Section: Wufi Implementationmentioning

confidence: 99%

Simulation of humidity and temperature distribution in green roof with pozzolana as drainage layer: Influence of outdoor seasonal weather conditions and internal ceiling temperature

Kazemi

Courard

2021

Science and Technology for the Built Environment

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“…The seriousness of the problem is shown by Svensson [5] reporting high relative humidity (between 80-90%) during the summer and even some condensation. In another study [6] the relative humidity in the crawl space was over 90% during the summertime.…”

Section: Introductionmentioning

confidence: 91%

Highly insulated crawl spaces with controlled minimal ventilation – proof of concept by field measurements

Airaksinen¹,

Olsson

Kurnitski

et al. 2020

E3S Web Conf.

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In current practices crawl spaces are typically ventilated with outdoor air. This leads very often to high relative humidity especially in the beginning of the summer, which can be problematic if the excess humidity cannot be ventilated efficiently enough. This paper introduces a crawl space concept where the crawl space is highly insulated and traditional ventilation openings are replaced by minimal mechanical exhaust ventilation set by pressure difference with the aim to prevent potential pollutants to penetrate indoors through the base floor. The concept that has been developed based on the simulation study is tested in this study with field measurements in four single family houses. Continuous measurements of relative humidity and temperature in crawl spaces and outdoor air were running more than one year in each building. The results revealed that all the crawl spaces had very low relative humidity, mostly below 75% and for very short periods close to 80% even though some of the buildings were new and construction phase moisture was drying out. The results revealed that the crawl space concept studied provided an ultimate moisture safety and can be recommended for all buildings with wooden floor.

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“…4. The more detailed content of this study's heat and moisture transport modelling is presented by Salo et al[37].…”

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confidence: 99%

Radon, fungal spores and MVOCs reduction in crawl space house: A case study and crawl space development by hygrothermal modelling

Keskikuru

Salo

Huttunen

et al. 2018

Building and Environment

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In this case study was to investigate how ventilation of the crawl space will influence on concentrations of radon, fungal spores and MVOCs in the crawl space and indoors of detached house. The crawl space pressurisation by exhaust air from indoors was successful to prevent the convective flow of radon from the soil, but it increased microbial growth in the crawl space. After installation of the supply and exhaust ventilation in the crawl-space and in the living space, the concentrations of fungal spores in the crawl space and also entry of radon and MVOCs into a house decreased. A microbiologically safe crawl space was determined with hygrothermal simulation utilizing the Finnish Mould Growth Model and a two year examination period. The optional structures of the crawl space being depressurised with exhaust ventilation included an open base uncovered ground and various air-sealed closed structures. When mould growth of building materials was at medium resistant sensitivity class, mould was not observed during different air change rates in any of the examined structures. Open base uncovered gravel ground is a functional solution of a crawl space, only when there are no organic materials. The air-sealed ground structure is recommended build with concrete + insulation and when air exchange rate (ach) varied from 0.2 to 1 h-1. A concrete

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Numerical study of time-dependent hygrothermal conditions in depressurized crawl space

Cited by 4 publications

References 15 publications

Simulation of humidity and temperature distribution in green roof with pozzolana as drainage layer: Influence of outdoor seasonal weather conditions and internal ceiling temperature

Simulation of humidity and temperature distribution in green roof with pozzolana as drainage layer: Influence of outdoor seasonal weather conditions and internal ceiling temperature

Highly insulated crawl spaces with controlled minimal ventilation – proof of concept by field measurements

Radon, fungal spores and MVOCs reduction in crawl space house: A case study and crawl space development by hygrothermal modelling

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