Hygrothermal Behavior of Thermal Insulating Material Based on Technical Hemp and its Application in Construction

2013 ◽  
Vol 860-863 ◽  
pp. 1223-1226
Author(s):  
Jiri Zach ◽  
Jitka Peterková ◽  
Martin Sedlmajer
Keyword(s):  
Building Materials ◽  
Moisture Absorption ◽  
Moisture Transfer ◽  
Natural Fibers ◽  
High Moisture ◽  
Building Envelopes ◽  
Thermal Insulating ◽  
Energy Demands ◽  
Hygrothermal Behavior ◽  
Heat And Moisture

Natural insulation materials have great potential of development given the contemporary requirements of the society in terms of reducing the energy demands of the production of building materials and the reduction of CO2emissions. Natural fibers are characteristic by their high moisture absorption and combustibility. The paper describes the results of research in the field of heat and moisture transfer within the structure of insulating materials based on natural fibers (hemp). The results of the experiments provided input data for computational simulations of hygrothermal behavior of hemp based fiber insulation applied in building envelopes.

scholarly journals Numerical modelling and experimental study of heat and moisture properties of a wall based on date palm fibers concrete

2019 ◽  
Vol 85 ◽  
pp. 02009 ◽  
Author(s):  
Tarek Alioua ◽  
Boudjemaa Agoudjil ◽  
Abderrahim Boudenne
Keyword(s):  
Relative Humidity ◽  
Building Materials ◽  
Moisture Transfer ◽  
Natural Fibers ◽  
Good Prediction ◽  
The Finite Element Method ◽  
Hygrothermal Behavior ◽  
Date Palm Fibers ◽  
Different Depths ◽  
Heat And Moisture

In the present paper, we study with both experimental and numerical aspect the heat and moisture transfer properties of a wall based on concrete filled with the natural fibers. The wall was placed in climatic chamber and temperature and relative humidity were monitored at different depths. A developed model describing heat and moisture transfers in porous building materials was implemented in COMSOL Multiphysics and solved with the finite element method. The obtained results are compared with experimental data. A relatively good agreement was obtained for both temperature and relative humidity variation at different depths. Finally, the developed model gives almost a good prediction despite the classical difficulties encountered at the experiment, which is very promising for the prediction of the hygrothermal behavior of bio-based building materials at different conditions.

Study of Hygrothermal Behavior of Insulation Materials Based on Natural Fibers

2015 ◽  
Vol 1124 ◽  
pp. 97-102
Author(s):  
Jiri Zach ◽  
Jitka Peterková
Keyword(s):  
Building Materials ◽  
Natural Fibers ◽  
Natural Fibre ◽  
Heat Propagation ◽  
Natural Fibres ◽  
Low Carbon ◽  
Insulating Materials ◽  
Thermal Insulating ◽  
Hygrothermal Behavior ◽  
Insulating Properties

Natural fibre based thermal insulating materials belong to progressive building materials representing one of the possible ways in sustainable development and which are characterised with low carbon trace and low value of primary bound energy. In case of industrially produced insulating materials (for instance using thermal connection method) the insulating materials based on natural fibres showed comparable properties with industrially produced insulating materials on building markets. In the view of thermal insulating properties the natural insulating material show slightly different behavior in comparison with synthetic insulating materials which is caused by fibrous structure of insulating materials and low thermal conductivity of natural fibres (contrary to glass or mineral fibres). The paper describes results of research oriented on study of heat propagation within materials based on natural fibres originated from agriculture and stockbreeding.

scholarly journals Numerical Network Modeling of Heat and Moisture Transfer through Capillary-Porous Building Materials

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1819
Author(s):  
Borys Basok ◽  
Borys Davydenko ◽  
Anatoliy M. Pavlenko
Keyword(s):  
Building Materials ◽  
Moisture Transfer ◽  
Three Dimensional ◽  
Total Pore Volume ◽  
Equivalent Diameter ◽  
Average Pore ◽  
The Difference ◽  
Three Dimensional Coordinate ◽  
Solid Liquid ◽  
Heat And Moisture

The article presents the modeling of the dynamics of the vapor-gas mixture and heat and mass transfer (sorption-desorption) in the capillary structure of the porous medium. This approach is underpinned by the fact that the porous structure is represented by a system of linear microchannels oriented along the axes of a three-dimensional coordinate system. The equivalent diameter of these channels corresponds to the average pore diameter, and the ratio of the total pore volume to the volume of the entire porous material corresponds to its porosity. The entire channel area is modeled by a set of cubic elements with a certain humidity, moisture content, pressure and temperature. A simulation is carried out taking into account the difference in temperatures of each of the phases: solid, liquid and gas.

Development of a numerical approach to assess the effect of coupled heat and moisture transfer on energy consumption of residential buildings in Moroccan context

2021 ◽  
pp. 174425912110560
Author(s):  
Yassine Chbani Idrissi ◽  
Rafik Belarbi ◽  
Mohammed Yacine Ferroukhi ◽  
M’barek Feddaoui ◽  
Driss Agliz
Keyword(s):  
Energy Consumption ◽  
Building Materials ◽  
Moisture Transfer ◽  
Residential Buildings ◽  
Building Design ◽  
Energy Performance ◽  
Climatic Conditions ◽  
Heat And Moisture Transfer ◽  
Coupled Heat And Moisture ◽  
Heat And Moisture

Hygrothermal properties of building materials, climatic conditions and energy performance are interrelated and have to be considered simultaneously as part of an optimised building design. In this paper, a new approach to evaluate the energy consumption of residential buildings in Morocco is presented. This approach is based on the effect of coupled heat and moisture transfer in typical residential buildings and on their responses to the varied climatic conditions encountered in the country. This approach allows us to evaluate with better accuracy the response of building energy performance and the indoor comfort of building occupants. Annual energy consumption, cooling and heating energy requirements were estimated considering the six climatic zones of Morocco. Based on the results, terms related to coupled heat and moisture transfer can effectively correct the existing energy consumption calculations of the six zones of Morocco, which currently do not consider energy consumption due to coupled heat and moisture transfer.

scholarly journals Numerical modelling of a hemp concrete wall

2019 ◽  
Vol 85 ◽  
pp. 08003 ◽  
Author(s):  
Georges Costantine ◽  
Chadi Maalouf ◽  
Tala Moussa ◽  
Guillaume Polidori ◽  
Elias Kinab
Keyword(s):  
Building Materials ◽  
Moisture Transfer ◽  
Numerical Study ◽  
Object Oriented ◽  
Hysteresis Phenomenon ◽  
Energy Costs ◽  
Concrete Wall ◽  
Heat And Moisture ◽  
Account Heat ◽  
Indoor And Outdoor

In a global warming context associated to the abuse of energy consumption, actual researches focus more and more on reducing energy costs in the building sector. This target could be achieved by using innovative building materials, such as hemp concrete, due to its positive impacts on thermal and environmental levels. The aim of this work is to carry out a numerical study of a hemp concrete wall subjected to several indoor and outdoor conditions of temperature and relative humidity using the program object oriented SPARK. The hygrothermal behaviour of the wall is investigated taking into account heat and moisture transfer within the wall as well as hysteresis phenomenon between the sorption and desorption curves and their temperature dependency.

A Numerical and Experimental Study of Heat and Moisture Transfer With Phase Change and Mobile Condensates in Fibrous Insulation

2003 ◽  
Author(s):  
Jintu Fan ◽  
Xiaoyin Cheng
Keyword(s):  
Phase Change ◽  
Moisture Absorption ◽  
Moisture Transfer ◽  
Water Vapor Pressure ◽  
Heat And Moisture Transfer ◽  
Moisture Movement ◽  
Saturation State ◽  
New Model ◽  
Fibrous Insulation ◽  
Heat And Moisture

This paper reports on an improved model of coupled heat and moisture transfer with phase change and mobile condensates in fibrous insulation. The new model considered the moisture movement induced by the partial water vapor pressure, a super saturation state in condensing region as well as the dynamic moisture absorption of fibrous materials and the movement of liquid condensates. The results of the new model were compared and found in good agreement with the experimental ones. Numerical simulation was carried using the model to investigate the effect of various material parameters on the transport phenomena.

scholarly journals Hygrothermal Behavior of Earth-Based Materials: Experimental and Numerical Analysis

2020 ◽  
Vol 330 ◽  
pp. 01030
Author(s):  
Meriem Saidi ◽  
Amel Soukaina Cherif ◽  
Ezeddine Sediki ◽  
Belkacem Zeghmati
Keyword(s):  
Building Materials ◽  
Moisture Transfer ◽  
Transfer Problem ◽  
Numerical Study ◽  
Water Vapor Permeability ◽  
Average Moisture Content ◽  
Vapor Permeability ◽  
Hygrothermal Behavior ◽  
Coupled Heat And Moisture ◽  
Building Walls

Bio-based building materials such as earth bricks are attracting renewed interest throughout the world due to their thermal and environmental properties. In this work, a numerical study of the hygrothermal behavior of building walls consist of compressed earth bricks (CEB) and stabilized earth bricks (SEB) was performed. A two-dimensional Luikov model for evaluating the temperature and the moisture migration in porous building materials was proposed. The coupled heat and moisture transfer problem was modeled. The governing equations of a mathematical model were solved numerically with the finite difference method. Input parameters in the model and their dependency on stabilizers content were determined by laboratory experiments. In order to specify the effect of chemical stabilization on the heat and mass transfer within studied materials, average moisture content and temperature were presented as a function of time. Results show that the addition of chemical stabilizers enhances the heat transfer through the earthen materials and reduces their water vapor permeability.

scholarly journals Simulation Research on the Effect of Coupled Heat and Moisture Transfer on the Energy Consumption and Indoor Environment of Public Buildings

Energies ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 141 ◽  
Author(s):  
Shui Yu ◽  
Yumeng Cui ◽  
Yifei Shao ◽  
Fuhong Han
Keyword(s):  
Energy Consumption ◽  
Indoor Environment ◽  
Moisture Transfer ◽  
Building Envelope ◽  
Thermal Calculation ◽  
Heat And Moisture Transfer ◽  
Building Envelopes ◽  
Coupled Heat And Moisture ◽  
Heat And Moisture ◽  
Humidity Environment

A building envelope is a multi-layer porous structure. It transfers heat and moisture to balance the indoor and outdoor temperature difference and water vapor partial pressure difference. This is a typical coupled heat and moisture migration process. When the space is filled with moist air, water or ice, it will directly affect the thermal properties of the material. With respect to moisture coming through the wall into the indoor building, it will also affect the indoor environment and the energy consumption due to the formation of latent heat. However, the moisture transfer process in the building envelopes is not taken into account in the current conventional thermal calculation and energy consumption analysis. This paper analyzes the indoor thermal and humidity environment and building energy consumption of typical cities in Harbin, Shenyang, Beijing, Shanghai, and Guangzhou. The results show that it is obvious that the coupled heat and moisture transfer in the building envelopes has an impact on the annual cooling and heating energy consumption, the total energy consumption, and the indoor thermal and humidity environment. The geographical location of buildings ranging from north to south influences the effect of coupled heat and moisture transfer on the annual energy consumption of the building, moving from positive to negative. It is suggested that the additional coefficient of the coupled thermal and moisture method can effectively correct the existing energy consumption calculation results, which do not take the consumption from the coupled heat and moisture in the building envelopes into account.

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