scholarly journals Experimental investigation of the drying behaviour of the building materials

2020 ◽  
Vol 172 ◽  
pp. 17002
Author(s):  
Jianhua Zhao ◽  
Frank Meissener ◽  
John Grunewald ◽  
Shuo Feng
Keyword(s):  
Material Characterization ◽  
Building Materials ◽  
Moisture Transfer ◽  
Test Procedure ◽  
Drying Process ◽  
Ceramic Brick ◽  
Complex Process ◽  
Drying Behaviour ◽  
Heat And Moisture ◽  
Simultaneous Heat

The drying process gives an important insight for material characterization, during which the material experiences the moisture changing from saturation until the equilibrium with the environment, thus it sends both the liquid and vapor transport information. Drying in the material is a complex process that involves the simultaneous heat and moisture transfer. Due to its complex mechanism, currently there is no stipulation/rules on standardizing the drying test procedure of the moist building materials. In this paper, the drying behaviours of two building materials, ceramic brick and calcium silicate, are experimentally investigated. Different factors that influence their drying behaviours are explored. The approaches to assess the drying rate in two drying phases are also compared and discussed.

Fundamental Parameters of Heat and Moisture Transfer for Energy Efficiency in Buildings

2014 ◽  
Vol 632 ◽  
pp. 79-93 ◽  
Author(s):  
Stefania Liuzzi ◽  
P. Stefanizzi
Keyword(s):  
Energy Efficiency ◽  
Building Materials ◽  
Moisture Transfer ◽  
Physical Parameters ◽  
Heat And Moisture Transfer ◽  
Fundamental Parameters ◽  
Basic Concepts ◽  
Heat And Moisture ◽  
Simultaneous Heat ◽  
Hygrothermal Behaviour

Heat and moisture transfer in a room is critical for the indoor comfort.This first chapter introduces the basic concepts of heat and moisture transfer in buildings, dealing with the main theoretic fundamentals.It focuses on the most common parameters, used to analyze heat and moisture transfer in buildings.Furthermore this section takes into account a numerical model to calculate the simultaneous heat and moisture transfer in building materials.It is demonstrated that both the microstructure and physical parameters, e.g. density and porosity, may influence greatly the hygrothermal behaviour of the building materials. This is the reason why this chapter also gives prominence to the porous materials.

scholarly journals Testing of a new non-equilibrium heat and moisture transfer model in porous building materials

2020 ◽  
Vol 172 ◽  
pp. 04003
Author(s):  
Piotr Łapka ◽  
Michał Wasik ◽  
Łukasz Cieślikiewicz ◽  
Piotr Furmański
Keyword(s):  
Building Materials ◽  
Moisture Transfer ◽  
Reference Data ◽  
Transfer Model ◽  
Ceramic Brick ◽  
Heat And Moisture Transfer ◽  
Model Predictions ◽  
Heat And Moisture ◽  
Kinetics Of ◽  
Non Equilibrium

In this paper the new non-equilibrium model of heat and moisture transfer in heterogenous building materials is presented and tested. The new hygro-thermal model differs from the other approaches which are based on the classical assumption of instantaneous local mechanical, thermal and hygric equilibrium between vapour and water in the pores in building materials. Instead of this assumption the model uses the finite rate of transition of moisture from the liquid to the vapour state and vice versa while still keeping mechanical and thermal equilibrium between components of the medium. The linear kinetics of this transition is applied. The assessment of the model correctness is also performed in the paper. In the first step of the testing the model predictions were successfully verified with the reference data obtained numerically. Then the model was validated using reference data obtained experimentally. Finally, the influence of volumetric mass transfer coefficient between vapour and water as well as water and vapour in pores is investigated, i.e., kinetics of the vapour-water/water-vapour transition is analysed. During the model testing traditional building material were considered (i.e., ceramic brick). However, the model may be used for investigation of hygro-thermal behaviour of bio-based materials.

Mathematical Models of Papermaking

2001 ◽  
Vol 6 (1) ◽  
pp. 9-19 ◽  
Author(s):  
A. Buikis ◽  
J. Cepitis ◽  
H. Kalis ◽  
A. Reinfelds ◽  
A. Ancitis ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Initial Value Problems ◽  
Moisture Transfer ◽  
Bound Water ◽  
Drying Process ◽  
Initial Value ◽  
First Order ◽  
Heat And Moisture ◽  
The Mathematical Model ◽  
The Web

The mathematical model of wood drying based on detailed transport phenomena considering both heat and moisture transfer have been offered in article. The adjustment of this model to the drying process of papermaking is carried out for the range of moisture content corresponding to the period of drying in which vapour movement and bound water diffusion in the web are possible. By averaging as the desired models are obtained sequence of the initial value problems for systems of two nonlinear first order ordinary differential equations. 

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 Identification of heat and mass transfer processes in bread during baking

2005 ◽  
Vol 9 (2) ◽  
pp. 73-86 ◽  
Author(s):  
Ivanka Zheleva ◽  
Vesselka Kambourova
Keyword(s):  
Partial Differential Equations ◽  
Moisture Content ◽  
Differential Equations ◽  
Moisture Transfer ◽  
Partial Differential ◽  
Linear Partial Differential Equations ◽  
Mass Transfer Processes ◽  
Model Equations ◽  
Heat And Moisture ◽  
Simultaneous Heat

A mathematical model representing temperature and moisture content in bread during baking is developed. The model employs the coupled partial differential equations proposed by Luikov. Dependences of mass and thermal properties of dough on temperature and moisture content are included in the model. Resulting system of non-linear partial differential equations in time and one space dimension is reduced to algebraic system by applying a finite difference numerical method. A numerical solution of the model equations is obtained and simultaneous heat and moisture transfer in dough during baking is predicted. The changes of temperature and moisture content during the time of the process are graphically presented and commented.

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