Next Article in Journal
The Effect of Localized Vibration during Welding on the Microstructure and Mechanical Behavior of Steel Welds
Previous Article in Journal
Investigation of Surface Roughness and Predictive Modelling of Machining Stellite 6
Previous Article in Special Issue
The Use of Eutectic Fe-Si-B Alloy as a Phase Change Material in Thermal Energy Storage Systems
Article Menu

Export Article

Open AccessArticle

Methods to Characterize Effective Thermal Conductivity, Diffusivity and Thermal Response in Different Classes of Composite Phase Change Materials

1
Dipartimento di Meccanica, Politecnico di Milano, Via La Masa 1, 20156 Milan, Italy
2
Dipartimento di Energia, Politecnico di Milano, Via Lambruschini 4, 20156 Milan, Italy
*
Author to whom correspondence should be addressed.
Materials 2019, 12(16), 2552; https://doi.org/10.3390/ma12162552
Received: 13 July 2019 / Revised: 6 August 2019 / Accepted: 8 August 2019 / Published: 10 August 2019
(This article belongs to the Special Issue Phase Change Materials for Thermal Energy Storage)
  |  
PDF [3728 KB, uploaded 13 August 2019]
  |  

Abstract

The phase change materials (PCMs) used in devices for thermal energy storage (TES) and management are often characterized by low thermal conductivity, a limit for their applicability. Composite PCMs (C-PCM), which combine active phase (proper PCM) with a passive phase with high conductivity and melting temperature have thus been proposed. The paper deals with the effect of length-scale on thermal characterization methods of C-PCM. The first part of the work includes a review of techniques proposed in the scientific literature. Up to now, special focus has been given to effective thermal conductivity and diffusivity at room or low temperature, at which both phases are solid. Conventional equipment has been used, neglecting length-scale effect in cases of coarse porous structures. An experimental set-up developed to characterize the thermal response of course porous C-PCMs also during active phase transition at high temperature is then presented. The setup, including high temperature-heat flux sensors and thermocouples to be located within samples, has been applied to evaluate the thermal response of some of the above C-PCMs. Experimental test results match Finite Elements (FE) simulations well, once a proper lattice model has been selected for the porous passive phase. FE simulations can then be used to estimate temperature difference between active and passive phase that prevents considering the C-PCM as a homogeneous material, to describe it by effective thermo-physical properties. In the engineering field, under these conditions, the design steps for TES systems design cannot be simplified by considering C-PCMs as homogeneous materials in FE codes. View Full-Text
Keywords: composite phase change materials; experimental methods; effective thermal conductivity; effective thermal diffusivity; heat flux probes composite phase change materials; experimental methods; effective thermal conductivity; effective thermal diffusivity; heat flux probes
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Gariboldi, E.; Colombo, L.P.M.; Fagiani, D.; Li, Z. Methods to Characterize Effective Thermal Conductivity, Diffusivity and Thermal Response in Different Classes of Composite Phase Change Materials. Materials 2019, 12, 2552.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Materials EISSN 1996-1944 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top