11 results on '"Biwole, Pascal"'
Search Results
2. A Mini-Review on Straw Bale Construction.
- Author
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Tlaiji, Ghadie, Biwole, Pascal, Ouldboukhitine, Salah, and Pennec, Fabienne
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HYGROTHERMOELASTICITY , *STRAW , *THERMAL insulation , *SPECIFIC heat , *BUILDING design & construction , *CARBON emissions , *THERMAL conductivity - Abstract
Straw bale building construction is attracting a revived public interest because of its potential for reduced carbon footprint, hygrothermal comfort, and energy savings at an affordable price. The present paper aims to summarize the current knowledge on straw bale construction, using available data from academic, industry, and public agencies sources. The main findings on straw fibers, bales, walls, and buildings are presented. The literature shows a wide variability of results, which reflects the diversity of straw material and of straw construction techniques. It is found that the effective thermal conductivity, density, specific heat, and elastic modulus of straw bales used in construction are in the range 0.033–0.19 W/(m·K), 80–150 kg/m3, 1075–2000 J/(kg·K), and 150–350 kPa respectively. Most straw-based multilayered walls comply with fire resistance regulations, and their U-value and sound reduction index range from 0.11 to 0.28 W/m2 K and 42 to 53 dB respectively, depending on the wall layout. When compared to standard buildings, straw bale buildings do provide yearly reductions in carbon emissions and energy consumption. The reductions often match those obtained after applying energy-saving technologies in standard buildings. The paper ends by discussing the future research needed to foster the dissemination of straw bale construction. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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3. Silica aerogel blankets as super insulating material
- Author
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Nocentini, Kevin, Biwole, Pascal Henry, Achard, Patrick, Centre Procédés, Énergies Renouvelables, Systèmes Énergétiques (PERSEE), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut Pascal (IP), SIGMA Clermont (SIGMA Clermont)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL), Mines Paris - PSL (École nationale supérieure des mines de Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
[SPI.GCIV]Engineering Sciences [physics]/Civil Engineering ,[SPI.GCIV.CD]Engineering Sciences [physics]/Civil Engineering/Construction durable ,thermal properties ,thermal insulation ,hygric properties ,[PHYS.MECA.THER]Physics [physics]/Mechanics [physics]/Thermics [physics.class-ph] ,super insulating materials ,aerogel blankets ,ComputingMilieux_MISCELLANEOUS ,[SPI.MAT]Engineering Sciences [physics]/Materials - Abstract
International audience
- Published
- 2018
4. Fostering energy efficiency in buildings through aerogel-based renders
- Author
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Ibrahim, Mohamad, Wurtz, Etienne, Achard, Patrick, Biwole, Pascal Henry, Centre Procédés, Énergies Renouvelables, Systèmes Énergétiques (PERSEE), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), CEA, LITEN, Service bâtiment et systèmes thermiques, Le Bourget du Lac, France, Laboratoire Jean Alexandre Dieudonné (JAD), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS), Mines Paris - PSL (École nationale supérieure des mines de Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Jean Alexandre Dieudonné (LJAD), Université Nice Sophia Antipolis (1965 - 2019) (UNS), and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA)
- Subjects
building rehabilitation ,[SPI.ENERG]Engineering Sciences [physics]/domain_spi.energ ,thermal insulation ,energy efficient envelopes ,aerogel-based rendering - Abstract
International audience; In France, the building sector is the largest consumer of energy and accounts for about 43% of the total energy consumption and 25% of the CO2 emissions. In this study, we present a recently developed insulating rendering based on silica-aerogels. It is mainly developed for exterior thermal insulation applications. In addition to new buildings, it can be used for retrofitting existing ones since it has a high insulation performance and its application is compatible with the traditional masonry facades using the well-known ordinary techniques. The objectives are to examine the hygrothermal performance of exterior walls and to estimate the energy performance of houses with and without this rendering. On an envelope scale, numerical simulations are carried out using the software WUFI. The latter solves the coupled heat and moisture transfer within a multi-layered wall. On a full-scale house, the energy performance is estimated by the aid of numerical simulations using the whole building energy simulation program EnergyPlus. Results have shown that adding the aerogel-based rendering reduces significantly the heat losses as well as the moisture risks.
- Published
- 2015
5. Experimental study of solid-liquid phase change in the presence of supercooling and natural convection.
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Shamseddine, Ibrahim, Biwole, Pascal Henry, Pennec, Fabienne, and Fardoun, Farouk
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SUPERCOOLING , *THERMAL insulation , *MECHANICAL shock , *HEAT storage , *SOLID-liquid interfaces - Abstract
This study experimentally investigates the supercooling and natural convection behavior in three PCM, namely pure octadecane (organic), a eutectic PCM, and sodium acetate trihydrate (inorganic). The aim is to explore the effect of different factors on the degree of supercooling and on the natural convection, and to provide data for numerical simulation models. Results show that the type of PCM, the temperature of the cooling fluid, and mechanical shocks have a direct effect on the degree of supercooling. The supercooled PCM shows a high sensitivity to any changes in the applied conditions. The thermal insulation of the unheated PCM boundaries has a major effect on the solidification and melting dynamics and topology, particularly regarding the solid-liquid interface. The cross-sectional temperature profiles, the inclination of the solid-liquid interface, and the melting rate show that regardless of the PCM, natural convection plays a significant role during heating but not during cooling. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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6. Building envelope with a new aerogel-based insulating rendering: Experimental and numerical study, cost analysis, and thickness optimization.
- Author
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Ibrahim, Mohamad, Biwole, Pascal Henry, Achard, Patrick, Wurtz, Etienne, and Ansart, Guillaume
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BUILDING envelopes , *ENERGY consumption of buildings , *ENERGY conservation in buildings , *THERMAL insulation , *THICKNESS measurement , *MATHEMATICAL optimization - Abstract
In France, renovation of existing buildings has a high priority. The thickness of insulation layers becomes a major issue of concern especially in cities. In this study, we present a recently developed insulating rendering based on silica aerogels that can be applied to new buildings and to retrofit existing ones. A full scale experimental house is built near Chambery in France, with the rendering applied on its external facades. The results of a numerical model developed in EnergyPlus are compared to the on-site measurements. After validating the numerical model, the thickness of the rendering is optimized based on a cost analysis for different climates for the case of retrofitting an old building. Then, a sensitivity analysis is carried out to determine the thickness dependency on annual heating load, present worth factor, rendering’s cost, and heating set-point. Results show that the optimum rendering thickness is in the range of 1.7–4.4 cm and the payback period in the range of 1.4–2.7 years depending on the climate. The optimum thickness increases with the increasing heating set-point and increasing present worth factor; however, it decreases with the increasing rendering cost. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
7. Hygro-thermal properties of silica aerogel blankets dried using microwave heating for building thermal insulation.
- Author
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Nocentini, Kevin, Achard, Patrick, and Biwole, Pascal
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SILICA gel , *THERMAL insulation , *MICROWAVE heating , *THERMAL properties of buildings , *SILICA nanoparticles - Abstract
Silica aerogels are highly porous and open-cell materials made of amorphous silica nanoparticles, interconnected in a 3D random network. Silica aerogel-based materials have a great potential as thermal insulation in building thanks to their very low thermal conductivity. However, pure silica aerogels are fragile with low mechanical moduli. Making aerogel composite materials by combining fibers with a pre-gel mixture of a gel precursor or by impregnating a fiber network by such a mixture seems to be a promising way to enhance the mechanical properties of such materials. After drying, the resulting composite is called aerogel blanket. The aerogel blanket is mechanically strengthened, flexible and still has a very low thermal conductivity. Aerogel blankets are usually dried using supercritical process but it is considered as a main drawback for large scale industrialization. The present study uses an innovative micro wave drying. The purpose of this work is to analyze and characterize a handy, light, super-insulating aerogel blanket dried in ambient conditions and see if it could be suitable for building thermal insulation. Two types of blankets have been investigated: the first one with a glass fiber web and the second one with a PET (polyethylene terephthalate) fiber web. Hygro-thermal characterizations were done and show that the aerogel blankets have an excellent thermal conductivity (0.015 W m −1 K −1 ) and a hydrophobic behavior. The studied aerogel blankets obtained using a new ambient drying process show practically the same characteristics as their counterpart dried with a supercritical process and mark a step forward in the aerogel blanket industrialization. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
8. Multi-scale thermal, energetic and economic analysis of composite insulating materials made of silica aerogel in a fibrous inorganic mat.
- Author
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Nocentini, Kevin, Ibrahim, Mohamad, Biwole, Pascal Henry, and Achard, Patrick
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INSULATING materials , *COMPOSITE materials , *AEROGELS , *THERMAL insulation , *THERMAL resistance , *THERMAL conductivity , *HEATING load - Abstract
• A mathematical model to predict the aerogel blanket's effective thermal conductivity at the material scale is developed considering the gaseous, radiative, and solid heat transfer. • The in-situ thermal performance of the aerogel-based blankets is estimated via a real-scale experimental test facility using the average method as well as using two dynamic statistical methods. • The annual energy performance and economic analysis of a single-family detached house with and without the aerogel-based blanket is examined for different climate. Composite materials made of silica aerogel in a fibrous inorganic mat, hereafter called "aerogel blankets", represent promising insulating materials that can overcome the low mechanical resistance of monolithic aerogels, while preserving their very low thermal conductivity. Firstly, this paper details an experimentally validated mathematical model to predict the aerogel blankets' effective thermal conductivity, as a function of the blankets' density, fiber volume fraction, and temperature. Secondly, an experimental test building retrofitted internally with a layer of needle glass fiber (NGF) aerogel blanket is monitored, and its thermal behavior is compared to the baseline case before the retrofit. The retrofitted wall U-value is derived from experimental data series using stationary and transient parametric methods. Then, a validated whole building Energy Plus numerical model is used to predict the annual energy consumption of a detached single-family house retrofitted with an NGF aerogel blanket, in the climates of Brussels (Belgium), Nice (France), and Stockholm (Sweden). Lastly, a 1-D COMSOL multiphysics model evaluates the economic profitability of installing the blanket as an interior thermal insulation system. Results show that the aerogel blankets have an effective thermal conductivity of about 0.0165 W.m−1.K−1. The designed mathematical model can reliably predict the gaseous conduction in the blanket, but deviations from the experimental measurements appear when considering the radiative and solid conduction components. The blanket's effective thermal conductivity increases with fiber volume fraction and temperature while its dependency curve to density is concave, with a minimum for densities of around 140 kg.m−3. Retrofitting a wall with 2.5 cm of NGF aerogel blanket as an internal insulation system almost doubles the thermal resistance of the experimental wall and decreases the heating load by more than 40 % in all tested climates. Internal thermal insulation with aerogel blankets is more profitable than conventional insulation materials, in places of high floor area price, because it can preserve the indoor living space. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
9. Hygrothermal performance of exterior walls covered with aerogel-based insulating rendering.
- Author
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Ibrahim, Mohamad, Wurtz, Etienne, Biwole, Pascal Henry, Achard, Patrick, and Sallee, Hebert
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HYGROTHERMOELASTICITY , *EXTERIOR walls , *AEROGELS , *RENDERING (Computer graphics) , *THERMAL insulation , *MASONRY , *NUMERICAL analysis - Abstract
In this study, we present a recently patented insulating rendering based on silica-aerogels. It is mainly developed for exterior thermal insulation applications. In addition to new buildings, it can be used for retrofitting existing ones since it has a high insulation performance and its application is easy, compatible with the traditional masonry facades, and using the well-known ordinary techniques. The objectives are to examine the hygrothermal performance of walls with this rendering and to compare different thermal insulation configurations. The methodology followed is developing a numerical model, then conducting an experimental set-up on a test-cell having the rendering on its south wall to validate the numerical model under real weather conditions. Different exterior wall structures are examined: no insulation, exterior insulation using this rendering, interior insulation, and interior and exterior insulation. Six assessment criteria are used: assembly water content, drying rate, mold growth, condensation risk, ASHRAE-160 criterion, and heat losses. Results show that interior thermal insulation systems can cause several moisture problems: inability to dry out over the years, condensation risk, etc. Adding the aerogel-based rendering on the exterior surface of the un-insulated or the already internally insulated walls reduces significantly or even removes the moisture risks. Also, it reduces significantly the wall heat losses. [ABSTRACT FROM AUTHOR]
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- 2014
- Full Text
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10. Corrigendum to ``Hygro-thermal properties of silica aerogel blankets dried using microwave heating for building thermal insulation'' [Energy and Buildings 158 (2018) 14–22].
- Author
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Nocentini, Kevin, Achard, Patrick, and Biwole, Pascal
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HYGROTHERMOELASTICITY , *THERMAL insulation - Published
- 2018
- Full Text
- View/download PDF
11. Hygrothermal performance of multilayer straw walls in different climates.
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Tlaiji, Ghadie, Pennec, Fabienne, Ouldboukhitine, Salah, Ibrahim, Mohamad, and Biwole, Pascal
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THERMAL insulation , *STRAW , *HYGROTHERMOELASTICITY , *MEDITERRANEAN climate , *TEMPERATE climate , *HUMIDITY ,TROPICAL climate - Abstract
• The temperature and relative humidity variations obtained by WUFI are in good agreement with the literature experimental findings. • The excessive moisture content in straw leads to bio-deterioration, mold, and decay damage in the whole structure. • The hygrothermal issues in a straw wall depend on the interior and exterior covering layers. • Hygrothermal issues can be solved by adding the straw thickness, adding a vapor retarder layer, adding an unventilated air layer, and controlling the indoor conditions. Straw is becoming a promising alternative insulation material to improve the building energy performance because of its low cost, large availability as cereal waste, its good hygrothermal properties, and its low embodied energy. The goal of this paper is to assess the hygrothermal performance of multi-layered straw walls with different boundary conditions. The study consists of evaluating five different straw-based wall assemblies, under a continental (Arkhangelsk, Russia), a tropical climate (Brasilia, Brazil), a temperate Mediterranean climate (Nice, France), and a cold desert climate Xinjiang (China). Numerical models of the heat and moisture transfer through the walls using WUFI software are developed, calibrated, and validated through experimental results from the literature. The chosen evaluation criteria are the total water content, the drying rate, the condensation risk, the mold growth, the moisture quantity, the time lag, and the decrement factor. Results show that straw walls with cement and/or wood covering can be used in tropical and temperate climates, coated straw walls with additional air layers in dry climates, while insulated straw walls are best fitted in continental climates. In the latter, the dryness rate varies between 7 and 40% with a low condensation risk of value in the range of 0–12%. It can be concluded that the straw wall's performance strongly depends on the interior and exterior added thermal insulation layers since they affect the ability of the material to dry out. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
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