Amandine Piot's research while affiliated with Cea Leti and other places

Publications (22)

Article
Full-text available
The building materials used indoors constantly interact with the environment in which the occupants live. Recent studies have shown that natural materials, such as wood, can improve human well-being. In addition, the building materials facing the indoor air are able to adsorb and desorb water vapour from their surface and exchange it with the surro...
Conference Paper
Full-text available
Moisture buffering can be defined as the effect on the atmosphere of the exchanges of water vapour between the surface layers of hygroscopic materials and the indoor environment. Since latent heat exchanges take place, the moisture buffering has a direct thermal effect on summer indoor temperatures. We propose here to investigate this thermal effec...
Article
Full-text available
Prediction of moisture transfer within material using a classic diffusive model may lack accuracy, since numerical simulations underestimate the adsorption process when a sample is submitted to variations of moisture level. Model equations are always established with assumptions. Consequently, some phenomena are neglected. This paper therefore inve...
Article
Heat and mass transfers are becoming increasingly important in the field of building physics. They should be considered to predict building performance, especially for a wall containing highly hygroscopic materials. The moisture balance at the room scale is influenced by air leakage and moisture sources, by the vapour transfer within the material a...
Article
Models for the prediction of heat and mass transfers in building porous materials have been developed since the 90’s with simulation programs such as MATCH, UMIDUS, DELPHIN and Wufi. These models are used to analyze the physical phenomena occurring and particularly the impact of moisture on buildings’ energy performance and durability. With this go...
Article
The standard methods to determine the vapour permeability and the moisture sorption curve may lack of accuracy since discrepancies are observed when comparing numerical predictions to experimental data. Moreover, these properties are determined in steady state conditions while the numerical predictions are carried in transient regime. Thus, this pa...
Article
Full-text available
In order to improve understanding of heat and mass transfer, two studies, at material and room scale are carried out. At the material scale, a dynamic experimental method has been developed and applied to a wood fiber previously characterized with classical steady-state methods. Several samples were subjected to successive steps of relative humidit...
Conference Paper
In order to improve understanding of heat and mass transfer, two studies, at material and room scale are carried out. At the material scale, a dynamic experimental method has been developed and applied to a wood fiber previously characterized with classical steady-state methods. Several samples were subjected to successive steps of relative humidit...
Article
The present work is the hygric characterization of wood fibre insulation boards, using dynamic measurements of relative humidity and sample weight, analyzed in the frame of Bayesian inference for parameter identification under uncertainty. It is an attempt at identifying detailed profiles of moisture-dependent properties, and thus a relatively high...
Article
Hemp concrete is becoming a popular building construction material, as it has a low environmental impact and helps reducing the heat conductivity of walls. The generally used binder is lime, but in this study a prompt natural cement binder was used. The objective of this study was to analyse the behaviour of a hempcrete wall in realistic conditions...
Conference Paper
Full-text available
RESUME. La prise en compte des transferts couplés chaleur-masse devient nécessaire afin de prédire la performance d'un bâtiment, notamment lorsque la paroi contient des matériaux hygroscopiques. La caractérisation des matériaux se fait habituellement avec des mesures en régime permanent ce qui n'est pas en accord avec les charges hydriques d'un bât...
Presentation
Full-text available
Experimental assessment of hemp-concrete walls Coupled heat and moisture numerical simulation of hemp-concrete in real conditions Use of bio based materials in buildings
Conference Paper
Full-text available
The use of bio-based materials in construction is significantly improving. One of the bio-based materials is hemp concrete which is a composite obtained by mixing a binder and the non-fibrous part of hemp, called shiv. This specific hemp concrete developed by Vicat is made with Prompt Natural Cement (PNC) as binder. In situ hygro-thermal performanc...
Conference Paper
Full-text available
The use of bio-based materials in construction is significantly improving. One of the bio-based materials is hemp concrete which is a composite obtained by mixing a binder and the nonfibrous part of hemp, called shiv. This specific hemp concrete developed by Vicat is made with Prompt Natural Cement (PNC). Hemp concrete is used for its insulating pr...
Conference Paper
Full-text available
The aim of this work is to understand the hygrothermal behaviour of hempcrete based on cement at a wall size level. For this both simulation and experimental measurements are conducted in parallel. In the experimental study two Passys test cells are used to compare 2 test walls, subjected to weather solicitations outside and hygrothermal regulati...
Conference Paper
Full-text available
Alternative products such as green materials are either back or newly implemented in the construction field. The low environmental impact of hemp concrete and its thermo-hydric behaviour show the possibilities of healthier construction and let obtain a better comfort of users. In contrast with usual concrete, the hemp concrete has huge hygroscopic...
Article
An experimental investigation has begun concerning the hygrothermal behaviour of wooden frame houses. The experimental set-up, consisting in a full-scale wooden frame house exposed to natural exterior climate is presented in the paper. It is located in Grenoble (South-East of France), and is equipped with over 150 sensors in order to collect a larg...
Conference Paper
Full-text available
Un modèle de transferts couplés chaleur-air-vapeur d’eau est sensible à de nombreux paramètres rendant difficile son ajustement vis-à-vis des résultats expérimentaux. Cette étude propose une approche simplifiée en s’appuyant sur des bilans en humidité appliqués à l’air intérieur d’une cellule test. Il est ainsi apparu qu’avec des parements intérieu...
Article
Wooden frame houses are very sensitive to air and moisture flows. Recent studies showed that such flows can seriously affect the quality and durability of buildings. \par After a brief description of the physics of heat and mass transfers, we present the experimental set-up that was built for this study. It consists in a wooden frame house, exposed...
Article
Les maisons à ossature bois sont des structures particulièrement sensibles aux flux d'air et d'humidité. Des études récentes ont montré que de telles sollicitations peuvent dégrader la qualité et la durabilité d'un bâtiment. Après avoir décrit la physique des transferts couplés d'énergie et de masse, nous présentons le support expérimental de cette...
Article
: A study was planned in order to improve the knowledge on heat, air and moisture transfers within light-weight building envelopes. In this aim, an experimental cell exposed to real climate, consisting of a small wooden frame structure and panel walls is being built. The aim of this large scale experiment is to evaluate the influence of different e...

Citations

... In (Nore et al., 2017) hygrothermal simulations of this phenomenon are validated using experiments in two test rooms made of solid wood. Similar room-scale numerical simulations in (Legros et al., 2020) show, that a spruce surface has a lower surface temperature and air temperature during the summer period when compared to painted plasterboards. They attribute these findings to the higher hygroscopicity of the spruce. ...
... Numerical hygrothermal models [28][29][30] have been developed in the literature, which take into account, at best, internal processes (vapor transport, sorption, etc.), but they also generally involve some unknown parameters concerning the sorption-desorption dynamics. Finally, significant discrepancies subsist between the predictions of these models and macroscopic measurements [31,32], suggesting the need of progress concerning the description of physical processes in these model. ...
... To establish the likelihood of moisture accumulation and mould growth, hygrothermal and bio-hygrothermal simulation tools are used to inform the design and construction processes [1][2][3][4]. Pliable building membranes are used to prevent the presence of unmanaged and excess indoor moisture from water vapour, which can lead to moisture accumulation, support mould growth, and Timber buildings [24][25][26][27][28]. However, more recent research has been undertaking more specific empirical validation tasks and questioning the material properties and calculation methods within the hygrothermal simulation tools. ...
... Numerical hygrothermal models [28][29][30] have been developed in the literature, which take into account, at best, internal processes (vapor transport, sorption, etc.), but they also generally involve some unknown parameters concerning the sorption-desorption dynamics. Finally, significant discrepancies subsist between the predictions of these models and macroscopic measurements [31,32], suggesting the need of progress concerning the description of physical processes in these model. ...
... Among the most common measurement methods (sweat guarded hot plates [7], permeation cells [8], or inverse methods applied to diffusion experiments [9,10]), the cup method [11][12][13] remains the most widely used thanks to its simplicity. Broadly, this test consists in measuring the moisture flow due to relative humidity gradient across a sample sealed on a cup containing desiccant or saturated salt solution under steady state and isothermal condition. ...
... Surface case hardening of materials which occurs towards the last period of drying can make the material surface impermeable to a greater degree, which plays a role to protect the material from rain and unfavourable weather conditions. Therefore, it is obvious that the moisture level of the materials used in building construction affects the moisture variations within the building [18,19]. Moreover, it can seriously affect the hygrothermal transfer in the building envelop [20]. ...
... This connection originates from an essential weakness in [1]'s measurement strategy, wherein solely relative humidities are measured while sample weight is not monitored. This is contrary to many other studies in this field [9][10][11][12], which typically combine measurements of relative humidity and sample weight during vapour sorption experiments. Let us assume a simple vapour sorption experiment, wherein a sample at initial vapour pressure pv,0 is exposed to an environment at vapour pressure pv,1 via one surface while the other surface is impermeable. ...
... Climate change is one of the biggest threats to the environment (weather contrasts with extremely low or high air temperatures, increased windiness, increased flooding in coastal areas, etc.); social environment (equal access to food and fresh water); and annual economic losses and changes must be made to mitigate the above impacts. To reduce the impact of climate change, the European Union has set a goal to reduce greenhouse gas emissions by 40% by 2030 [1]. Promoting the use of renewable energy and reducing non-renewable resources is an important means to achieve this goal. ...
... Their results confirmed the excellent moisture buffer capacity of hemp concrete, and the simulation results and experimental results are in good agreement. Piot et al. [31] also investigated the hygrothermal behavior of multilayer walls containing hemp concrete. The numerical simulation in the study results underestimated the dynamic change of relative humidity in a small-time range. ...
... Among the few works on hemp concrete durability, Bessette et al. [24] studied the effect of aging and mould growth during the manufacture of cement-based hemp concrete and during its exploitation. ...