An efficient numerical method for a long-term simulation of heat and mass transfer: the case of an insulated rammed earth wall

TL;DR

This paper introduces a novel Super-Time-Stepping numerical scheme that significantly reduces computational costs and allows larger time-steps for long-term heat and mass transfer simulations in insulated rammed earth walls.

Contribution

The study applies the Super-Time-Stepping method to building simulations, demonstrating its efficiency and accuracy in modeling drying processes of insulated rammed earth walls.

Findings

Achieves at least 100 times larger time-steps without loss of accuracy.

Reduces computational cost by over 92%.

Demonstrates effectiveness in long-term heat and mass transfer modeling.

Abstract

Innovative numerical scheme studied in this work enables to overcome two main limitations of Building Performance Simulation (BPS) programs as high computational cost and the choice of a very fine numerical grid. The method, called Super-Time-Stepping (STS), is novel to the state-of-the-art of building simulations, but has already proved to be sufficiently efficient in recent studies from anisotropic heat conduction in astrophysics (Meyer et al. 2014). The given research is focused on employment of this adopted numerical method to model drying of a rammed earth wall with an additional insulation layer. The results show considerable advantage of the STS method compared to standard Euler explicit scheme. It is possible to choose at least 100 times bigger time-steps to maintain high accuracy and to cut computational cost by more than 92% in the same time.