Abstract
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.
Highlights
Many models for multi-dimensional analysis of heat and moisture transfer in heterogenous porous building materials have been proposed [1,2,3,4,5,6,7,8,9]
In order to correctly predict the hygro-thermal behaviour of building materials or elements of building structures the heat and mass transfer should be modelled simultaneously and in the coupled way
The new non-equilibrium model of hygro-thermal behaviour of porous building materials consists of three coupled equations which account for vapour, water and energy balance, respectively
Summary
Many models for multi-dimensional analysis of heat and moisture transfer in heterogenous porous building materials have been proposed [1,2,3,4,5,6,7,8,9]. New models which deal with nonequilibrium moisture transfer in the heterogenous porous building materials have been proposed [11-16] These models assumed finite rate of mass transfer between vapour and water and vice versa. It was shown that if the proper kinetics for describing the transformation of moisture from gaseous to liquid state and vice versa is chosen these models may be applied to account for combined heat and moisture transfer in bio-based building materials in which classical assumption about hygric equilibrium between gaseous and liquid moisture is not valid [11, 12]. Influence of volumetric mass transfer coefficient which describes the dynamics of transition between gaseous and liquid moisture and vice versa in pores of building material investigated
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
