scholarly journals Characterization of Unripe and Mature Avocado Seed Oil in Different Proportions as Phase Change Materials and Simulation of Their Cooling Storage

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 107
Author(s):  
Evelyn Reyes-Cueva ◽  
Juan Francisco Nicolalde ◽  
Javier Martínez-Gómez
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Seed Oil ◽  
Energy System ◽  
Maturity Stage ◽  
Natural Environments ◽  
Renewable Materials ◽  
Scanning Calorimetry ◽  
Avocado Seed

Environmental problems have been associated with energy consumption and waste management. A solution is the development of renewable materials such as organic phase change materials. Characterization of new materials allows knowing their applications and simulations provide an idea of how they can developed. Consequently, this research is focused on the thermal and chemical characterization of five different avocado seed oils depending on the maturity stage of the seed: 100% unripe, 25% mature-75% unripe, 50% mature-50% unripe, 75% mature-25% unripe, and 100% mature. The characterization was performed by differential scanning calorimetry, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The best oil for natural environments corresponded to 100% matured seed with an enthalpy of fusion of 52.93 J·g−1, and a degradation temperature between 241–545 °C. In addition, the FTIR analysis shows that unripe seed oil seems to contain more lipids than a mature one. Furthermore, a simulation with an isothermal box was conducted with the characterized oil with an initial temperature of −14 °C for the isothermal box, −27 °C for the PCM box, and an ambient temperature of 25 °C. The results show that without the PCM the temperature can reach −8 °C and with it is −12 °C after 7 h, proving its application as a cold thermal energy system.

scholarly journals Characterization of Thermophysical Properties of Phase Change Materials Using Unconventional Experimental Technologies

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4687
Author(s):  
Arnold Martínez ◽  
Mauricio Carmona ◽  
Cristóbal Cortés ◽  
Inmaculada Arauzo
Keyword(s):  
Thermal Properties ◽  
Phase Change ◽  
Thermophysical Properties ◽  
Phase Change Materials ◽  
Small Sample ◽  
Alternative Methods ◽  
Accurate Estimation ◽  
Inhomogeneous Materials ◽  
Scanning Calorimetry

The growing interest in developing applications for the storage of thermal energy (TES) is highly linked to the knowledge of the properties of the materials that will be used for that purpose. Likewise, the validity of representing processes through numerical simulations will depend on the accuracy of the thermal properties of the materials. The most relevant properties in the characterization of phase change materials (PCM) are the phase change enthalpy, thermal conductivity, heat capacity and density. Differential scanning calorimetry (DSC) is the most widely used technique for determining thermophysical properties. However, several unconventional methods have been proposed in the literature, mainly due to overcome the limitations of DSC, namely, the small sample required which is unsuitable for studying inhomogeneous materials. This paper presents the characterization of two commercial paraffins commonly used in TES applications, using methods such as T-history and T-melting, which were selected due to their simplicity, high reproducibility, and low cost of implementation. In order to evaluate the reliability of the methods, values calculated with the proposed alternative methods are compared with the results obtained by DSC measurements and with the manufacturer’s technical datasheet. Results obtained show that these non-conventional techniques can be used for the accurate estimation of selected thermal properties. A detailed discussion of the advantage and disadvantage of each method is given.

Preparation and Characterization of Tetradecanol Microcapsule Phase Change Materials by Emulsion Polymerization

2015 ◽  
Vol 1089 ◽  
pp. 137-141 ◽  
Author(s):  
Xiao Qiu Song ◽  
Long Di Cao ◽  
Dan Dan Xu
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Good Thermal Stability ◽  
Result Show ◽  
Ft Ir ◽  
Latent Heats ◽  
Test Result

In this study, it was aimed at preparing and characterizating of poly (methyl methacrylate) (PMMA) shell microcapsules containing tetradecanol as phase change materials (PCMs) for thermal energy storage. The tetradecanol microcapsules were characterized by using scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The test result show that the contents of tetradecanol in microcapsules nearly 57.5% and the latent heats of melting and freezing were found to be 120.7 and 118.4 J/g. TGA analyses also indicated that the microPCMs degraded in two steps and have good thermal stability.

Characterization Phase Change Materials (PCM) Using T-History Method

2016 ◽  
Author(s):  
Navin Kumar ◽  
Debjyoti Banerjee
Keyword(s):  
Phase Change ◽  
Experimental Validation ◽  
Phase Change Materials ◽  
Reference Sample ◽  
Cost Effective ◽  
Experimental Protocol ◽  
Scanning Calorimetry ◽  
Numerical Predictions ◽  
Change Material

“T-history method” is widely used for characterization of thermal properties of Phase Change Material (PCM). In this study improvements are proposed to the experimental protocol used in the conventional T-History method. Experimental validation of numerical predictions for various samples of PCM were performed using the proposed measurement technique. This enabled the evaluation of the improvements in the proposed approach as well as for analyzing the experimental results. This involved measurement of temperature at the surface and in the center of the PCM samples (as well as that of the reference sample materials). The proposed modifications enable enhanced accuracy for estimation of the material properties (when compared to the conventional approaches). The estimates from the proposed approach were observed to be within 10% of the measured values obtained using Differential Scanning Calorimetry (DSC). The proposed approach is amenable to testing large sample sizes, is simpler to implement, provides more rapid data collection and is more cost-effective than that obtained using standard DSC protocols.

scholarly journals Thermal Analysis of Organic and Nanoencapsulated Electrospun Phase Change Materials

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 995
Author(s):  
Evdoxia Paroutoglou ◽  
Peter Fojan ◽  
Leonid Gurevich ◽  
Göran Hultmark ◽  
Alireza Afshari
Keyword(s):  
Phase Change ◽  
Latent Heat ◽  
Phase Change Materials ◽  
Electrospun Fiber ◽  
Sodium Dodecyl ◽  
Scanning Calorimetry ◽  
Electrospinning Technique ◽  
Improve Energy Efficiency ◽  
Change Temperature

Latent heat stored in phase change materials (PCM) can greatly improve energy efficiency in indoor heating/cooling applications. This study presents the materials and methods for the formation and characterization of a PCM layer for a latent heat thermal energy storage (LHTES) application. Four commercially available PCMs comprising the classes of organic paraffins and organic non-paraffins were selected for thermal storage application. Pure organic PCM and PCM in water emulsions were experimentally investigated. PCM electrospun microfibers were produced by a co-axial electrospinning technique, where solutions of Polycaprolactone (PCL) 9% w/v and 12% w/v in dichloromethane (DCM) were used as the fiber shell materials. PCM emulsified with sodium dodecyl sulfate (SDS), and Polyvinylalcohol 10% w/v (PVA) constituted the core of the fibers. The thermal behavior of the PCM, PCM emulsions, and PCM electrospun fibers were analyzed with differential scanning calorimetry (DSC). A commercial organic paraffin with a phase change temperature of 18 °C (RT 18) in its pure and emulsified forms was found to be a suitable PCM candidate for LHTES. The PVA-PCM electrospun fiber matrix of the organic paraffin RT18 with a PCL concentration of 12% w/v showed the most promising results leading to an encapsulation efficiency of 67%.

Phase Change Materials: A Prospective Solution for Surface Layers of Building Envelopes

2015 ◽  
Vol 749 ◽  
pp. 415-419
Author(s):  
Zbyšek Pavlík ◽  
Anton Trník ◽  
Milena Pavlíková ◽  
Jan Fořt ◽  
Robert Černý
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Phase Changes ◽  
Surface Layers ◽  
Scanning Calorimetry ◽  
Powder Density ◽  
The Difference ◽  
And Storage ◽  
Change Material

A Phase Change Material (PCM) based on paraffinic wax encapsulated in polymer shell is used for improvement of the heat storage capacity of commercially produced dry plaster, originally developed for both exterior and interior hand application. The composition of PCM modified plasters is designed with respect to the workability of fresh mixtures. Characterization of applied PCM is done using the measurement of particle size distribution, powder density, and matrix density. For the newly developed composite plasters, basic physical properties, mechanical properties, and thermal properties are accessed, whereas a specific attention is paid to the Difference Scanning Calorimetry (DSC) analysis. Using DSC measurement, temperatures of phase change transitions and phase changes enthalpies are identified. The obtained results show that the temperature induced phase change can be used for the release and storage of thermal energy in buildings, which can be beneficially utilized for saving the energy spent for the achievement of the indoor thermal comfort.

scholarly journals Experimental Characterization of Phase Change Materials for Refrigeration Processes

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3033
Author(s):  
Anastasia Stamatiou ◽  
Lukas Müller ◽  
Roger Zimmermann ◽  
Jamie Hillis ◽  
David Oliver ◽  
...  
Keyword(s):  
Energy Density ◽  
Phase Change ◽  
Thermophysical Properties ◽  
Phase Change Materials ◽  
Cost Effective ◽  
Latent Heat Storage ◽  
Lower Energy Density ◽  
Change Material ◽  
Storage Units

Latent heat storage units for refrigeration processes are promising as alternatives to water/glycol-based storage due to their significantly higher energy densities, which would lead to more compact and potentially more cost-effective storages. In this study, important thermophysical properties of five phase change material (PCM) candidates are determined in the temperature range between −22 and −35 °C and their compatibility with relevant metals and polymers is investigated. The goal is to complement existing scattered information in literature and to apply a consistent testing methodology to all PCMs, to enable a more reliable comparison between them. More specifically, the enthalpy of fusion, melting point, density, compatibility with aluminum, copper, polyethylene (PE), polypropylene (PP), neoprene and butyl rubber, are experimentally determined for 1-heptanol, n-decane, propionic acid, NaCl/water mixtures, and Al(NO3)3/water mixtures. The results of the investigations reveal individual strengths and weaknesses of the five candidates. Further, 23.3 wt.% NaCl in water stands out for its very high volumetric energy density and n-decane follows with a lower energy density but better compatibility with surrounding materials and supercooling performance. The importance of using consistent methodologies to determine thermophysical properties when the goal is to compare PCM performance is highlighted.

scholarly journals pH-controlled synthesis of sustainable lauric acid/SiO2 phase change material for scalable thermal energy storage

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shafiq Ishak ◽  
Soumen Mandal ◽  
Han-Seung Lee ◽  
Jitendra Kumar Singh
Keyword(s):  
Electron Microscopy ◽  
Phase Change ◽  
Lauric Acid ◽  
Photoelectron Spectroscopy ◽  
Phase Change Materials ◽  
Precursor Solution ◽  
Thermal Reliability ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Heating And Cooling

AbstractLauric acid (LA) has been recommended as economic, eco-friendly, and commercially viable materials to be used as phase change materials (PCMs). Nevertheless, there is lack of optimized parameters to produce microencapsulated PCMs with good performance. In this study, different amounts of LA have been chosen as core materials while tetraethyl orthosilicate (TEOS) as the precursor solution to form silicon dioxide (SiO2) shell. The pH of precursor solution was kept at 2.5 for all composition of microencapsulated LA. The synthesized microencapsulated LA/SiO2 has been characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-Ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), and Transmission electron microscopy (TEM). The SEM and TEM confirm the microencapsulation of LA with SiO2. Thermogravimetric analysis (TGA) revealed better thermal stability of microencapsulated LA/SiO2 compared to pure LA. PCM with 50% LA i.e. LAPC-6 exhibited the highest encapsulation efficiency (96.50%) and encapsulation ratio (96.15%) through Differential scanning calorimetry (DSC) as well as good thermal reliability even after 30th cycle of heating and cooling process.

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