Temperature effects on the effective thermal conductivity of phase change materials with two distinctive phases

2011 ◽  
Vol 38 (10) ◽  
pp. 1344-1348 ◽  
Author(s):  
X.H. Yang ◽  
T.J. Lu ◽  
T. Kim
Keyword(s):  
Thermal Conductivity ◽  
Phase Change ◽  
Effective Thermal Conductivity ◽  
Temperature Effects ◽  
Phase Change Materials

scholarly journals Improvement of Phase Change Materials (PCM) Used for Solar Process Heat Applications

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1260
Author(s):  
Cristina Prieto ◽  
Anton Lopez-Roman ◽  
Noelia Martínez ◽  
Josep M. Morera ◽  
Luisa F. Cabeza
Keyword(s):  
Thermal Conductivity ◽  
Solar Energy ◽  
Phase Change ◽  
Effective Thermal Conductivity ◽  
High Temperatures ◽  
Phase Change Materials ◽  
Material Selection ◽  
Inert Atmosphere ◽  
Enhancement Effect ◽  
Process Heat

The high intermittency of solar energy is still a challenge yet to be overcome. The use of thermal storage has proven to be a good option, with phase change materials (PCM) as very promising candidates. Nevertheless, PCM compounds have typically poor thermal conductivity, reducing their attractiveness for commercial uses. This paper demonstrates the viability of increasing the PCM effective thermal conductivity to industrial required values (around 4 W/m·K) by using metal wool infiltrated into the resin under vacuum conditions. To achieve this result, the authors used an inert resin, decoupling the specific PCM material selection from the enhancement effect of the metal wools. To ensure proper behavior of the metal wool under standard industrial environments at a broad range of temperatures, a set of analyses were performed at high temperatures and an inert atmosphere, presenting a thorough analysis of the obtained results.

scholarly journals RECOVERING OF ANISOTROPIC THERMAL PROPERTIES IN PHASE-CHANGE MATERIALS USING DIRECT AND INVERSE MATHEMATICAL MODELLING

2021 ◽  
Author(s):  
Sergey Markov
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Mathematical Modelling ◽  
Phase Change ◽  
Effective Thermal Conductivity ◽  
Phase Change Materials ◽  
Conductivity Tensor ◽  
Thermal Conductivity Tensor

We present the results of applying the developed algorithms for direct and reverse mathematical modelling to calculate the effective thermal conductivity tensor in samples of phase-change materials.

Development of plug-ins to predict effective thermal conductivity of woven and microencapsulated phase change composite

2016 ◽  
Vol 51 (6) ◽  
pp. 733-743
Author(s):  
Muhammad Owais Raza Siddiqui ◽  
Danmei Sun
Keyword(s):  
Thermal Conductivity ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Phase Change ◽  
Effective Thermal Conductivity ◽  
Phase Change Materials ◽  
Research Work ◽  
Element Analysis ◽  
Microencapsulated Phase Change Materials ◽  
Automatic Model Generation

The thermal property of textile structures plays an important role in the understanding of thermal behaviour of the clothing. In this work, user-friendly GUI plug-ins have been developed to generate both microscopic and mesoscopic scale models for finite element analysis. The plug-ins were developed by using Abaqus/CAE as a platform. The GUI Plug-ins enable automatic model generation and prediction of the effective thermal conductivity of woven composite and microencapsulated Phase Change Materials composites via finite element analysis by applying boundary conditions. The predicted effective thermal conductivities from plug-ins have been compared with the results obtained from published experimental research work based on an established mathematical model. They are correlated well. Moreover, the influence of phase change materials on heat transfer behaviour of microencapsulated Phase Change Materials composites was further analysed.

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

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2552 ◽  
Author(s):  
Elisabetta Gariboldi ◽  
Luigi P. M. Colombo ◽  
Davide Fagiani ◽  
Ziwei Li
Keyword(s):  
Thermal Conductivity ◽  
High Temperature ◽  
Phase Change ◽  
Effective Thermal Conductivity ◽  
Phase Change Materials ◽  
Thermal Response ◽  
Active Phase ◽  
Length Scale ◽  
Fe Simulations ◽  
Passive Phase

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.

Enhanced performances of macro-encapsulated phase change materials (PCMs) by intensification of the internal effective thermal conductivity

Energy ◽  
2013 ◽  
Vol 55 ◽  
pp. 956-964 ◽  
Author(s):  
Nicolas Calvet ◽  
Xavier Py ◽  
Régis Olivès ◽  
Jean-Pierre Bédécarrats ◽  
Jean-Pierre Dumas ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Phase Change ◽  
Effective Thermal Conductivity ◽  
Phase Change Materials

An Effective Thermal Conductivity Model for Architected Phase Change Material Enhancer

2020 ◽  
Author(s):  
Romain Hubert ◽  
Olivier Bou-Matar ◽  
Jerome Foncin ◽  
Philippe Coquet ◽  
Dunlin Tan ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Source ◽  
Phase Change ◽  
Effective Thermal Conductivity ◽  
Phase Change Materials ◽  
Heated Surface ◽  
Analytical Investigation ◽  
Heat Of Fusion ◽  
Conductivity Enhancement ◽  
Thermal Conductivity Model

Abstract Phase Change Materials (PCM) have been widely used for thermal energy storage due to their high latent heat of fusion. However, PCMs suffer from their very low thermal conductivity which limits heat spreading around the heat source. Without proper thermal conductivity enhancement, melting would mainly occur at the interface between the heated surface and the PCM, and would slowly spread in the bulk of the PCM, greatly reducing its performance. Metallic foams are usually used as thermal conductivity enhancer, yet recent progress in additive manufacturing have allowed architected structures to be used and optimized. We present here an analytical investigation of the effective thermal conductivity of porous architected structures and emphasize is made on the effect of thermal constriction at the interface with a heat spreader in contact with the heat source.

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