scholarly journals Characterization of Responsive Plasters for Passive Moisture and Temperature Control

2020 ◽  
Vol 10 (24) ◽  
pp. 9116
Author(s):  
Jan Fořt ◽  
Jan Kočí ◽  
Jaroslav Pokorný ◽  
Luboš Podolka ◽  
Michal Kraus ◽  
...  
Keyword(s):  
Phase Change ◽  
Energy Performance ◽  
Specific Enthalpy ◽  
Scanning Calorimetry ◽  
Reduction Strategies ◽  
Air Control ◽  
Change Material ◽  
Moisture Buffering

Ambient comfort maintenance accompanied by excessive energy consumption is hugely criticized concerning the limited sustainability of the building sector in the long-term. In this sense, the energy reduction strategies based on the employment of passive air-control techniques are viewed as a prospective solution for improved energy performance. In order to contribute to this significant issue, this paper is aimed at the design and material characterization of novel plaster with an improved thermal and humidity control performance. For this purpose, a form-stable diatomite/dodecanol-based phase change material together with superabsorbent polymer are used as admixtures for the passive moderation of indoor air quality by newly designed modified plasters. The experimental assessment of the functional properties by means of mechanical strength, thermal conductivity, and hygric properties is performed. Considering the goal of the paper, particular attention is paid to the characterization of water vapor storage and moisture buffering according to the Nordtest method. Differential scanning calorimetry is employed for the description of phase change intervals as well as the specific enthalpy of phase change. The obtained results point to significant improvements in the hygroscopic performance and increased thermal energy storage that can be used for passive moderation of the indoor temperature and reduction of the relative humidity swings.

Preparation and characterization of phase-change energy storage nonwoven fabric

2021 ◽  
pp. 152808372110417
Author(s):  
Zhou Zhao ◽  
Ningning Tong ◽  
Hong Song ◽  
Yan Guo ◽  
Jinmei Wang
Keyword(s):  
Phase Transition ◽  
Thermal Stability ◽  
Energy Storage ◽  
Phase Change ◽  
Nonwoven Fabric ◽  
Scanning Calorimetry ◽  
Change Material ◽  
Stretching Process ◽  
Thermal Stability Of

In this work, a phase-change energy storage nonwoven fabric was made of polyurethane phase-change material (PUPCM) by a non-woven melt-blown machine. Polyethylene glycol 2000 was used as the phase transition unit and diphenyl-methane-diisocyanate as the hard segment to prepare PUPCM. Thermal stability of the PUPCM was evaluated through thermal stability analysis. The performance of pristine PUPCM was determined by Fourier transform infrared spectroscopy and differential scanning calorimetry to analyze the spinning technology of spinning temperature and the stretching process. Phase-change energy storage nonwoven fabric (413.22 g/m2) was prepared, and the morphology, solid–solid exothermic phase transition, mechanical properties, and the structures were characterized. The enthalpy of solid–solid exothermic phase transition reached 60.17 mJ/mg (peaked at 23.14°C). The enthalpy of solid–solid endothermic phase transition reached 67.09 mJ/mg (peaked at 34.34°C). The strength and elongation of phase-change energy storage nonwoven fabric were found suitable for garments and tent fabrics.

Synthesis and Characterization of a Novel Phase Change Luminescence Materials

2013 ◽  
Vol 750-752 ◽  
pp. 1150-1154
Author(s):  
Qi Song Shi ◽  
Lin Cao ◽  
Lei Wang ◽  
Xiao Feng ◽  
Xin Yi Jin ◽  
...  
Keyword(s):  
Phase Change ◽  
Luminescent Properties ◽  
Synthesis And Characterization ◽  
Poly Ethylene Glycol ◽  
Scanning Calorimetry ◽  
Carboxylate Groups ◽  
Result Show ◽  
Poly Ethylene ◽  
Change Material

In this study, a novel phase change material was prepared by coordinating rare earth Tb3+ions to the carboxylate groups of a poly (ethylene glycol).The properties of the material were characterized by differential scanning calorimetry (DSC), infrared spectroscopy (IR) and fluorescence spectroscopy. The synthesis and characterization a novel phase change luminescent Tb-PEG/SA material were described in this paper. The result show that this modified PEG material show both good phase change properties and excellent luminescent properties.

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.

Application of Fatty Acid Based Phase-Change Material to Reduce Energy Consumption From Roofs of Buildings

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Ahmad K. Sleiti ◽  
Edward J. Naimaster
Keyword(s):  
Fatty Acid ◽  
Energy Consumption ◽  
Phase Change ◽  
Phase Change Material ◽  
Thermal Energy ◽  
Energy Performance ◽  
Department Of Energy ◽  
Total Energy Consumption ◽  
Scanning Calorimetry ◽  
Change Material

Buildings account for a significant portion of the total energy consumption in the U.S., especially the energy-inefficient commercial building sector. As part of the future path toward realizing net zero energy buildings, innovative energy-efficient technologies must be developed. In this study, the potential of phase-change material (PCM)-enhanced constructions to lower heating, ventilating, and air conditioning (HVAC) energy consumption in a commercial restaurant building was investigated. A commercially available fatty acid based PCM product was selected due to their promising thermal and chemical properties. Differential scanning calorimetry (DSC) was used in isothermal step mode to accurately measure the latent heat energy storage of the PCM. A U.S. Department of Energy (DOE) commercial reference building model with a PCM-enhanced ceiling was simulated using a finite-difference conduction heat transfer algorithm in EnergyPlus to determine the effects of the PCM on the building energy performance. It was found that, although the PCM-enhanced ceiling had a beneficial stabilizing effect on the interior surface temperature of the ceiling, the zone mean air temperatures were not significantly altered. As such, minimal HVAC energy savings were seen. Future work should focus on active PCM systems, which utilize heat exchanging fluids to discharge the PCM to remove the stored thermal energy of the PCM during the night in summer, overcoming the fundamental issue of the passive PCM system returning stored thermal energy back into the building.

scholarly journals Preparation and Characterization of Expanded Clay-Paraffin Wax-Geo-Polymer Composite Material

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2191 ◽  
Author(s):  
Ahmed Hassan ◽  
Najif Ismail ◽  
Abdel-Hamid Mourad ◽  
Yasir Rashid ◽  
Mohammad Laghari
Keyword(s):  
Phase Change ◽  
Elevated Temperatures ◽  
Polymer Composite Material ◽  
Temperature History ◽  
Vacuum Impregnation ◽  
Scanning Calorimetry ◽  
Size And Morphology ◽  
The Stability ◽  
Change Material

Paraffin-based phase change material (PCM) is impregnated into the pores of lightweight expanded clay aggregate (LECA) through vacuum impregnation to develop PCM containing macro-capsules of LECA. Three different grades of LECA varying in size and morphology are investigated to host the PCM to determine the impregnation effectiveness, viability for coating, and its stability. The produced LECA-PCM is coated with geopolymer paste (GP) to provide leak proofing during the phase change. The PCM is thermophysically characterized by employing differential scanning calorimetry (DSC) and the temperature history method (THM) to determine the phase transition and the latent heat. The stability of the macro-capsules is determined by weight loss through rapid thermal cycling (RTC) at elevated temperatures. Leakage of the PCM is tested using the diffusion-oozing circle test (DOCT). The results show that the GP coated LECA-PCM macro-capsules achieved 87 wt % impregnation efficiencies and no noticeable loss of PCM, which indicates leak proofing of the developed capsules up to 1000 RTC.

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.

Maximizing Plant Efficiency While Minimizing Water Usage Through Use of a Phase Change Material-Based Cold Energy Storage System

2018 ◽  
Author(s):  
Joshua Charles ◽  
Carlos Romero ◽  
Sudhakar Neti ◽  
Chunjian Pan ◽  
Xingchao Wang ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Cooling System ◽  
System Optimization ◽  
Cfd Modeling ◽  
Scanning Calorimetry ◽  
Term Operation ◽  
Chloride Hexahydrate ◽  
Change Material

A supplemental main steam condenser cooling system is under development, which utilizes a phase change material (PCM). This PCM rejects heat to the cool atmosphere at night until it is fully frozen. The frozen PCM is available for condenser cooling during peak daytime electric demand. Three calcium chloride hexahydrate (CaCl2·6H2O)-based PCMs were selected for development after being characterized using differential scanning calorimetry (DSC). Additives to minimize supercooling and phase separation have demonstrated good performance after long and short-term thermal cycling. Corrosion testing under both isothermal and cycling conditions was conducted to determine long-term compatibility between several common metals and the selected PCMs. Several metals were demonstrated to have acceptably low corrosion rates for long-term operation, despite continual immersion in the selected hydrated salts. A system optimization model was developed, which utilizes a 3D modeling approach called the Layered Thermal Resistance (LTR) model. This model efficiently models the nonlinear, transient solidification process by applying analytic equations to layers of PCM. Good agreement was found between this model and more traditional computational fluid dynamics (CFD) modeling. Next phases of the work includes prototype testing and a techno-economic analysis of the technology.

Potential of Phase Change Material-Enhanced Constructions in Commercial Buildings

2012 ◽  
Author(s):  
Edward J. Naimaster ◽  
Ahmad K. Sleiti
Keyword(s):  
Energy Consumption ◽  
Phase Change ◽  
Phase Change Material ◽  
Energy Savings ◽  
Chemical Properties ◽  
Energy Performance ◽  
Commercial Building ◽  
Total Energy Consumption ◽  
Scanning Calorimetry ◽  
Change Material

Buildings account for a significant portion of the total energy consumption in the US, especially the energy-inefficient commercial building sector. As part of the future path towards realizing net zero energy buildings, innovative energy-efficient technologies must be developed. In this study, the potential of phase change material (PCM)-enhanced constructions to lower HVAC energy consumption in a commercial building was investigated. A commercially available fatty acid-based PCM product was selected due promising thermal and chemical properties. Differential scanning calorimetry (DSC) was used in isothermal step mode to accurately measure the latent heat energy storage of the PCM. A US DOE commercial reference building model with a PCM-enhanced ceiling was simulated using a finite-difference conduction heat transfer algorithm in EnergyPlus to determine the effects of the PCM on the building energy performance. It was found that, although the PCM-enhanced ceiling had a beneficial stabilizing effect on the interior surface temperature of the ceiling, the zone mean air temperatures were not significantly altered. As such, minimal HVAC energy savings were seen. Future work should focus on the potential of active PCM constructions, which could successfully remove stored thermal energy from the PCM without increasing the space cooling energy consumption.

Accelerated long-term assessment of thermal and chemical stability of bio-based phase change materials

2016 ◽  
Vol 40 (4) ◽  
pp. 299-310 ◽  
Author(s):  
Jignesh S Patel ◽  
Elizabeth Gao ◽  
Veera M Boddu ◽  
Larry D Stephenson ◽  
Ashok Kumar
Keyword(s):  
Differential Scanning Calorimetry ◽  
Phase Change ◽  
Phase Change Material ◽  
Latent Heat ◽  
Chemical Stability ◽  
Phase Change Materials ◽  
Scanning Calorimetry ◽  
Change Material ◽  
Scanning Electron

Thermal energy storage systems incorporated with phase change materials have potential applications to control energy use by building envelopes. However, it is essential to evaluate long-term performance of the phase change materials and cost-effectiveness prior to full-scale implementation. For this reason, we have used the accelerated long-term approach for studying the thermal performance and chemical stability of a commercially available bio-based phase change material during thermal cycling over a simulated period of 20 years. The phase change material was subjected to accelerate thermal aging under controlled environmental conditions. Small samples of the phase change material were periodically removed to measure its latent heat, thermal decomposition, and chemical stability using various analytical methods such as differential scanning calorimetry, thermogravimetry analysis, and infrared spectroscopy. The topographic changes in the phase change material due to the aging process were observed using scanning electron microscopy. The differential scanning calorimetry data indicate a significant reduction of 12% in the latent heat during heating and cooling cycles during the initial 6.2 years remain nearly constant thereafter. The thermogravimetry analysis results showed that the phase change material has excellent thermal stability within the working temperature range and also shows long-term decomposition temperature stability. The Fourier transform infrared spectra of the phase change material indicate absorption of moisture but the phase change material was chemically stable over the duration of accelerated aging cycles. After several aging cycles, the baseline surface morphology appeared to be changed from uniform mix of phase change material with microstructures to segregated microstructures as evidenced by the observation of the scanning electron micrographs.

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.

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