Analysis of coupled heat and moisture transfer in masonry structures

TL;DR

This paper investigates the effective thermal conductivity in masonry structures considering coupled heat and moisture transfer, using finite element simulations to analyze boundary condition effects and nonlinear interactions.

Contribution

It provides a detailed analysis of boundary condition impacts and demonstrates a practical approach for evaluating coupled heat and moisture transfer using standard finite element codes.

Findings

No significant difference among boundary condition types for effective conductivity

Coupled nonlinear heat and moisture transfer can be effectively modeled with standard finite element software

Results facilitate practical assessment of masonry thermal properties

Abstract

Evaluation of effective or macroscopic coefficients of thermal conductivity under coupled heat and moisture transfer is presented. The paper first gives a detailed summary on the solution of a simple steady state heat conduction problem with an emphasis on various types of boundary conditions applied to the representative volume element -- a periodic unit cell. Since the results essentially suggest no superiority of any type of boundary conditions, the paper proceeds with the coupled nonlinear heat and moisture problem subjecting the selected representative volume element to the prescribed macroscopically uniform heat flux. This allows for a direct use of the academic or commercially available codes. Here, the presented results are derived with the help of the SIFEL (SIimple Finite Elements) system.