scholarly journals Experimental Investigation on Graphene Oxide/SrCl2·6H2O Modified CaCl2·6H2O and the Resulting Thermal Performances

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1507 ◽  
Author(s):  
Zhiyang Jin ◽  
Yuanyuan Tian ◽  
Xiaoxiao Xu ◽  
Hongzhi Cui ◽  
Waiching Tang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Phase Change ◽  
Phase Change Materials ◽  
Test Results ◽  
Scanning Calorimetry ◽  
Average Temperature ◽  
Supercooling Degree ◽  
Nucleation Agents ◽  
Heat Value ◽  
Change Temperature

Although the inorganic salt hydrate phase change materials (PCMs) such as CaCl2·6H2O have promising potential for thermal energy storage in building application, the issue of supercooling has restricted their practical application. In this study, graphene oxide (GO) and SrCl2·6H2O as binary nucleation agents were used to modify CaCl2·6H2O and reduce its supercooling degree. Compared with pure CaCl2·6H2O, the incorporation of graphene oxide (GO)/SrCl2·6H2O reduced the supercooling degree to 0.3 °C significantly. In addition, the supercooling degree of modified CaCl2·6H2O after 200 thermal cycles was still much lower than that of non-modified CaCl2·6H2O. From the results of differential scanning calorimetry (DSC), the latent heat value and phase change temperature of the modified CaCl2·6H2O were 207.88 J/g and 27.6 °C, respectively. Aluminum capsules were used to encapsulate the modified PCM and placed inside the composite wallboard. The thermal performances of the composite wallboard with modified PCM were investigated using infrared thermography. Experimental results showed that the average temperature difference between the top and bottom surfaces of modified CaCl2·6H2O/wallboard composite after 1 h heating was kept around 15.8 °C, while it was 4.9 °C for the control wallboard. The above test results proved that the modified CaCl2·6H2O demonstrated good thermal performance and can be used in buildings to maintain thermal comfort.

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%.

Preparation and Study of Polyethylene Glycol (PEG)/Titanium Dioxide (TiO2) Phase Change Materials

2011 ◽  
Vol 284-286 ◽  
pp. 214-218 ◽  
Author(s):  
Hai Yang Kang ◽  
Gui Juan Li
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Sol Gel ◽  
Scanning Calorimetry ◽  
Dsc Measurements ◽  
Good Potential ◽  
Ft Ir ◽  
Change Temperature ◽  
Thermal Energy Storage Material ◽  
General Method

This paper adopted the general method of sol-gel to prepare a list of PEG/TiO2 phase change materials (PCMs). The chemical structure of the materials was investigated by FT-IR respectively. The infrared indicate that the materials have good chemical compatibility. The thermal properties of the samples were measured by differential scanning calorimetry(DSC) and thermogravimetry(TG). The surface topography and crystallized behavior of the materials were detected by SEM and XRD. The TG thermographs show the samples can sustain high temperature about 212°C. The DSC measurements display that the phase change temperature of the materials’ range from 52°C to 56°C. The results obtained from experiments show that the phase change materials possesses a good potential as a thermal energy storage material.

scholarly journals Investigation of Lactones as Innovative Bio-Sourced Phase Change Materials for Latent Heat Storage

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1300 ◽  
Author(s):  
Rebecca Ravotti ◽  
Oliver Fellmann ◽  
Nicolas Lardon ◽  
Ludger Fischer ◽  
Anastasia Stamatiou ◽  
...  
Keyword(s):  
Phase Change ◽  
Latent Heat ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Scanning Calorimetry ◽  
Latent Heat Storage ◽  
Chemical Structures ◽  
Wide Range ◽  
Temperature Ranges ◽  
Change Temperature

In the presented work, five bio-based and bio-degradable cyclic esters, i.e. lactones, have been investigated as possible phase change materials for applications in latent heat storage systems. Commercial natural lactones such as ε-caprolactone and γ-valerolactone were easily purchased through chemical suppliers, while 1,2-campholide, oxa-adamantanone and dibenzochromen-6-one were synthesized through Baeyer-Villiger oxidation. The compounds were characterized with respect to attenuated total reflectance spectroscopy and gas chromatography coupled with mass spectroscopy, in order to confirm their chemical structures and identity. Subsequently, thermogravimetric analysis and differential scanning calorimetry were used to measure the phase change temperatures, enthalpies of fusion, degradation temperatures, as well to estimate the degree of supercooling. The lactones showed a wide range of phase change temperatures from −40 °C to 290 °C, making them a high interest for both low and high temperature latent heat storage applications, given the lack of organic phase change materials covering phase change temperature ranges below 0 °C and above 80 °C. However, low enthalpies of fusion, high degrees of supercooling and thermal degradations at low temperatures were registered for all samples, rendering them unsuitable as phase change materials.

scholarly journals Preparation and Characterization of Novel Plaster with Improved Thermal Energy Storage Performance

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3318 ◽  
Author(s):  
Jan Fořt ◽  
Radimír Novotný ◽  
Anton Trník ◽  
Robert Černý
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Scanning Calorimetry ◽  
Change Temperature ◽  
Negative Impacts ◽  
A Minor ◽  
Thermal Energy Storage Systems

Thermal energy storage systems based on latent heat utilization represent a promising way to achieve building sustainability and energy efficiency. The application of phase change materials (PCMs) can substantially improve the thermal performance of building envelopes, decrease the energy consumption, and support the thermal comfort maintenance, especially during peak periods. On this account, the newly formed form-stable PCM (FSPCM) based on diatomite impregnated by dodecanol is used as an admixture for design of interior plasters with enhanced thermal storage capability. In this study, the effect of FSPCM admixture on functional properties of plasters enriched by 8, 16 and 24 wt.% is determined. On this account, the assessment of physical, thermal, hygric, and mechanical properties is done in order to correlate obtained results with applied FSPCM dosages. Achieved results reveal only a minor influence of applied FSPCM admixture on material properties when compared to negative impacts of commercially produced PCMs. The differential scanning calorimetry discloses variations of the phase change temperature, which ranging from 20.75 °C to 21.68 °C and the effective heat capacity increased up to 15.38 J/g accordingly to the applied FSPCM dosages.

Effect of Latent Heat on Insulation Characteristics in Phase Change Roof

2013 ◽  
Vol 275-277 ◽  
pp. 687-690
Author(s):  
Meng Gao ◽  
Jing Wang ◽  
Guo Zhong Wu
Keyword(s):  
Phase Change ◽  
Latent Heat ◽  
Heat Transfer Characteristic ◽  
Phase Change Materials ◽  
Influencing Factor ◽  
Transfer Characteristic ◽  
Unsteady Heat Transfer ◽  
Average Temperature ◽  
Change Temperature ◽  
Hourly Distribution

Under summer climatic features of Daqing area in China, numerical simulation on the unsteady heat transfer characteristic of phase change roof was investigated, considering direct influence of solar radiation. The main influencing factor of latent heat in the phase change roof was analyzed in this paper. The results show that, latent heat in different phase change temperature has little effect on hourly distribution of average temperature and average heat flux of base upper surface. Choosing appropriate phase transition temperature is still the key to take efficient and reasonable adventage of phase change materials in the roof structures.

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.

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.

A Study on the Cooling Characteristics of TMA Clathrate Compound with Additives

2006 ◽  
Vol 326-328 ◽  
pp. 1275-1278 ◽  
Author(s):  
Chang Oh Kim ◽  
Jin Heung Kim ◽  
Nak Kyu Chung
Keyword(s):  
Heat Source ◽  
Phase Change ◽  
Specific Heat ◽  
Freezing Point ◽  
Phase Change Temperature ◽  
Source Temperature ◽  
Heat Source Temperature ◽  
Clathrate Compound ◽  
Supercooling Degree ◽  
Change Temperature

This study aims to find out cooling characteristics of TMA 25wt%-water clathrate compound with ethanol such as supercooling, phase change temperature and specific heat. For this purpose, ethanol is added as per weight concentration and cooling experiment is performed at -6, -7 and -8, cooling heat source temperature, and it leads the following result. (1) Phase change temperature is decreased due to freezing point depression phenomenon. Especially, it is minimized as 5.1 and 5.0, 3.8 according to cooling source temperature in case that 0.5wt% of ethanol is added. (2) If 0.5wt% of ethanol is added, average supercooling degree is 0.9 and minimum supercooling is 0.8, 0.7 according to cooling heat source temperature. The restraint effect of supercooling is shown. (3) Specific heat shows tendency to decrease if ethanol is added. It is 3.013~3.048 kJ/kgK according to cooling heat source temperature if 0.5wt% of ethanol is added. Phase change temperature higher than that of water and inhibitory effect against supercooling can be confirmed through experimental study on cooling characteristics of TMA 25wt%-water clathrate compound by adding additive, ethanol.

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