Determination of the Crystallisation Kinetics of Fast-Growth Phase-Change Materials for Mark-Formation Prediction

The thermal dynamic behavior of buildings represents an important aspect of the energy efficiency and thermal comfort of the indoor environment. For this, phase change material (PCM) wallboards integrated into building envelopes play an important role in stabilizing the temperature of the human comfort condition. This article provides an assessment of the thermal behavior of a “bi-zone” building cell, which was built based on high-energy performance (HEP) standards and heated by a solar water heater system through a hydronic circuit. The current study is based on studying the dynamic thermal behavior, with and without implantation of PCMs on envelope structure, using a simplified modeling approach. The evolution of the average air temperature was first evaluated as a major indicator of thermal comfort. Then, an evaluation of the thermal behavior’s dynamic profile was carried out in this study, which allowed for the determination of the PCM rate anticipation in the thermal comfort of the building cell.

Download Full-text

Thermodynamics and kinetics of glassy and liquid phase-change materials

Materials Science in Semiconductor Processing ◽

10.1016/j.mssp.2021.106094 ◽

2021 ◽

Vol 135 ◽

pp. 106094

Author(s):

Narges Amini ◽

Julian Pries ◽

Yudong Cheng ◽

Christoph Persch ◽

Matthias Wuttig ◽

...

Keyword(s):

Liquid Phase ◽

Phase Change ◽

Phase Change Materials ◽

Thermodynamics And Kinetics ◽

Kinetics Of

Download Full-text

Cement-Based Renders Manufactured with Phase-Change Materials: Applications and Feasibility

Advances in Materials Science and Engineering ◽

10.1155/2016/7254823 ◽

2016 ◽

Vol 2016 ◽

pp. 1-6 ◽

Cited By ~ 10

Author(s):

Luigi Coppola ◽

Denny Coffetti ◽

Sergio Lorenzi

Keyword(s):

Compressive Strength ◽

Phase Change ◽

Phase Change Materials ◽

Residential Buildings ◽

Setting Time ◽

Drying Shrinkage ◽

Hydration Kinetics ◽

Mechanical Performances ◽

Entrapped Air ◽

Kinetics Of

The paper focuses on the evaluation of the rheological and mechanical performances of cement-based renders manufactured with phase-change materials (PCM) in form of microencapsulated paraffin for innovative and ecofriendly residential buildings. Specifically, cement-based renders were manufactured by incorporating different amount of paraffin microcapsules—ranging from 5% to 20% by weight with respect to binder. Specific mass, entrained or entrapped air, and setting time were evaluated on fresh mortars. Compressive strength was measured over time to evaluate the effect of the PCM addition on the hydration kinetics of cement. Drying shrinkage was also evaluated. Experimental results confirmed that the compressive strength decreases as the amount of PCM increases. Furthermore, the higher the PCM content, the higher the drying shrinkage. The results confirm the possibility of manufacturing cement-based renders containing up to 20% by weight of PCM microcapsules with respect to binder.

Download Full-text

Reviewing the Exergy Analysis of Solar Thermal Systems Integrated with Phase Change Materials

Energies ◽

10.3390/en14030724 ◽

2021 ◽

Vol 14 (3) ◽

pp. 724

Author(s):

Macmanus Chinenye Ndukwu ◽

Lyes Bennamoun ◽

Merlin Simo-Tagne

Keyword(s):

Phase Change ◽

Phase Change Materials ◽

Second Law Of Thermodynamics ◽

Heat Transfer Fluid ◽

Solar Still ◽

Thermal Systems ◽

Solar Systems ◽

Exergy Balance ◽

Change Material

The application of thermal storage materials in solar systems involves materials that utilize sensible heat energy, thermo-chemical reactions or phase change materials, such as hydrated salts, fatty acids paraffin and non-paraffin like glycerol. This article reviews the various exergy approaches that were applied for several solar systems including hybrid solar water heating, solar still, solar space heating, solar dryers/heaters and solar cooking systems. In fact, exergy balance was applied for the different components of the studied system with a particular attention given to the determination of the exergy efficiency and the calculation of the exergy during charging and discharging periods. The influence of the system configuration and heat transfer fluid was also emphasized. This review shows that not always the second law of thermodynamics was applied appropriately during modeling, such as how to consider heat charging and discharging periods of the tested phase change material. Accordingly, the possibility of providing with inappropriate or not complete results, was pointed.

Download Full-text

Phase Change Materials - From Structures to Kinetics

MRS Proceedings ◽

10.1557/proc-0918-h04-03 ◽

2006 ◽

Vol 918 ◽

Cited By ~ 1

Author(s):

Matthias Wuttig ◽

Wojciech Welnic ◽

Ralf Detemple ◽

Henning Dieker ◽

Johannes Kalb ◽

...

Keyword(s):

Phase Change ◽

Crystalline State ◽

Phase Change Materials ◽

Amorphous State ◽

Structural Difference ◽

Fast Time ◽

Optical Contrast ◽

Fast Time Scale ◽

Kinetics Of ◽

Structure Properties

AbstractPhase change materials possess a unique combination of properties which include a pronounced property contrast between the amorphous and crystalline state, i.e. a high electrical and optical contrast. In particular the latter observation is indicative for a considerable structural difference between the amorphous and crystalline state. At the same time the crystallization of the amorphous state proceeds on a fast time scale. This raises the question how structure, properties and kinetics are related in phase change alloys. It will be demonstrated that only a small group of covalent semiconductors with octahedral-like coordination has the required property combination. This is related to their thermodynamic properties which govern the kinetics of crystallization.

Download Full-text

Determination of enthalpy temperature curves of phase change materials with the temperature-history method: improvement to temperature dependent properties

Measurement Science and Technology ◽

10.1088/0957-0233/14/2/305 ◽

2003 ◽

Vol 14 (2) ◽

pp. 184-189 ◽

Cited By ~ 131

Author(s):

Jos M Mar n ◽

Bel n Zalba ◽

Luisa F Cabeza ◽

Harald Mehling

Keyword(s):

Phase Change ◽

Phase Change Materials ◽

Temperature History ◽

Temperature Dependent ◽

Temperature Dependent Properties ◽

Method Improvement

Download Full-text

Crystal Growth Rates in Doped SbxTe Fast-Growth Phase-Change Films Studied with Transmission Electron Microscopy

MRS Proceedings ◽

10.1557/proc-1072-g04-04 ◽

2008 ◽

Vol 1072 ◽

Author(s):

Bart J. Kooi ◽

Ramanathaswamy Pandian ◽

Jeff Th. M. De Hosson

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Crystal Growth ◽

Phase Change ◽

Growth Phase ◽

Growth Rates ◽

Fast Growth ◽

Various Boundary Conditions ◽

Dielectric Layers ◽

Transmission Electron

ABSTRACTIsothermal crystallization of doped SbxTe fast-growth phase-change films was investigated using transmission electron microscopy with in situ heating. SbxTe films with four different values for the Sb/Te ratio, x=3.0, 3.3, 3.6 and 4.2, were analyzed and the films were sandwiched between two types of dielectric layers. One dielectric layer type is based on 80at.%ZnS-20at.%SiO2, the other on (Ge,Cr)N. The crystal growth rates reduce if the phase-change films are sandwiched between amorphous dielectric layers. The reduction is very pronounced at the lowest measured temperatures (150 °C), becomes smaller at higher temperatures and probably disappears at around 200 °C. The crystal growth rates increase with increasing Sb/Te ratio, but the activation energy for crystal growth is not significantly affected by the Sb/Te ratio. Finally a systematic study of the effect of the electron beam of the TEM on the crystal growth rates is performed showing accelerated growth rates. The present work shows that particularly at relative low temperatures, just above the glass-transition temperature, the growth rates as limited by the atomic mobilities are sensitive to various (boundary) conditions, e.g. capping layers and irradiation.

Download Full-text