Discussion of “Thermal conductivity of porous building materials: An exploration of new challenges in fractal modelling solutions”

Authors

  • Hans Janssen KU Leuven, Departmentof Civil Engineering, Building Physics & Sustainable Design

DOI:

https://doi.org/10.21809/rilemtechlett.2024.199

Keywords:

Thermal conductivity, Porous materials, Fractal dimension, Fractal geometry, Discussion

Abstract

In November 2023 this journal published “Thermal conductivity of porous building ma­terials: An exploration of new challenges in fractal modelling solutions”.  That paper gauges four fractal building materials’ thermal conductivity models, concluding that fractal-geometry-based approa­ches appear “a promising method” as they “demonstra­te high reliability in repro­ducing experimental data”.  This discussion of the pa­per aims to shine a different light on the potential of fractal thermal conductivity models.  It shows that good agreement with experimental data usually ori­ginates from calibration of various “physical” factors comprised in these models, with the fitted numbers commonly deviating from physical rea­lity.  Moreover, exemplary instances reveal that good agreement with experimental data is obtained des­pite misinterpretation of measured outcomes or critical defects in model development, or, exceptio­nally, due to fabrication of validation information.  This discussion does hence not share the pa­per’s positive opinion on the prospects of fractal-geometry-ba­sed ther­­mal conductivity models, and advises caution instead.

Reproduction of [1]’s Figure 15, with additional highlighting of three characteristic data point clusters. Therein k+ is normalised thermal conductivity [-] (effective conductivity over fluid conductivity) and Sw [-] is saturation degree (moisture volume over pore volume).

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Published

07.11.2024

How to Cite

(1)
Janssen, H. Discussion of “Thermal Conductivity of Porous Building Materials: An Exploration of New Challenges in Fractal Modelling solutions.” RILEM Tech Lett 2024, 9, 10-16.

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Section

Articles