scholarly journals Thermal Response Of An Aerated Concrete Wall With Micro-Encapsulated Phase Change Material

2015 ◽  
Vol 23 (2) ◽  
pp. 19-22
Author(s):  
Dušana Halúzová
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Thermal Response ◽  
Concrete Wall ◽  
Laboratory Equipment ◽  
R Program ◽  
Concrete Blocks ◽  
Aerated Concrete ◽  
Encapsulated Phase Change Material ◽  
Change Material

Abstract For many years Phase Change Materials (PCM) have attracted attention due to their ability to store large amounts of thermal energy. This property makes them a candidate for the use of passive heat storage. In many applications, they are used to avoid the overheating of the temperature of an indoor environment. This paper describes the behavior of phase change materials that are inbuilt in aerated concrete blocks. Two building samples of an aerated concrete wall were measured in laboratory equipment called “twin-boxes”. The first box consists of a traditional aerated concrete wall; the second one has additional PCM micro-encapsulated in the wall. The heat flux through the wall was measured and compared to simulation results modeled in the ESP-r program. This experimental measurement provides a foundation for a model that can be used to analyze further building constructions.

Reducing Heat Conduction of Autoclaved Aerated Concrete Wall Using Phase Change Material

2013 ◽  
Vol 807-809 ◽  
pp. 2779-2783
Author(s):  
Atthakorn Thongtha ◽  
Somchai Maneewan ◽  
Chantana Punlek ◽  
Yothin Ungkoon
Keyword(s):  
Heat Conduction ◽  
Phase Change ◽  
Phase Change Material ◽  
Thermal Source ◽  
Concrete Wall ◽  
Autoclaved Aerated Concrete ◽  
Thermal Delay ◽  
Aerated Concrete ◽  
Change Material ◽  
Minimum Heat

In this work, the effect of the salt hydrated phase change material (PCM) on microstructure and heat conduction of the autoclaved aerated concrete (AAC) was studied. The microstructure in the AAC and AAC with composed phase change material was imaged by scanning electron microscopy (SEM). The ability in heat conduction was compared among AAC (AAC1), AAC with composed phase change material (0.417 (AAC2) and 0.833 (AAC3) kg/m2 in contents), and AAC which was composed by PCM (0.417 (AAC4) and 0.833 (AAC5) kg/m2 in contents) and was coated by the cement in 2 sides. These ones were tested the thermal delay at 40, 50 and 60 °C using the heater that was the thermal source. It was found that the optimum content of PCM on top surface was found at 0.417 kg/m2 because the minimum heat conduction and the lowest average temperatures of inside wall and inside room were shown in this sample at 40, 50 and 60 °C.

A Simplified Model for Encapsulated Phase Change Material

1999 ◽  
Author(s):  
Linda J. Hayes ◽  
Michael A. Spieker ◽  
Eugene H. Wissler ◽  
David P. Colvin
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Thermal Management ◽  
Latent Heat ◽  
Phase Change Materials ◽  
Flow In Porous Media ◽  
Simplified Model ◽  
Encapsulated Phase Change Material ◽  
Change Material ◽  
Conductive Media

Abstract One of the emerging technologies of this decade is macroencapsulated phase change materials (PCM), which is being developed to provide significantly enhanced thermal management for coolants, textile fibers, foams, composites and coatings with applications to avionics, spacesuits, machine coolants, apparel, packaging, and agriculture (Kaska and Chen, 1985, Colvin and Mulligan 1989). The encapsulated PCM is embedded or suspended in a conductive media. The characteristics of the capsules, the phase change material and the conductive media can be designed so as to provide enhanced thermal management in a wide variety of applications. The traditional way to model this system is to take a macroscopic view of the entire system, to use a volume averaged value for the release of latent heat from the PCM and to incorporate this term into the standard heat conduction equation. We propose a simplified model which has its origins in flow in porous media. The system is modeled with two components, the underlying conductive material and the phase change capsules. The amount of latent heat released from the PCM capsules is determined by the local temperature in the capsules, which can differ from the temperature in the conducting media. This model closely represents the physical systems which are being modeled Numerical results using this model are compared to experimental data from a garment layer which is constructed using macroencapsulated PCM capsules.

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

Energies ◽  
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.

Numerical Thermal Performance Investigation of an Electric Motor Passive Cooling System Employing Phase Change Materials

2021 ◽  
Author(s):  
Ali Deriszadeh ◽  
Filippo de Monte ◽  
Marco Villani
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Electric Motor ◽  
Phase Change Materials ◽  
Cooling System ◽  
Passive Cooling ◽  
Time Step ◽  
Cooling Performance ◽  
Passive Cooling System ◽  
Change Material

Abstract This study investigates the cooling performance of a passive cooling system for electric motor cooling applications. The metal-based phase change materials are used for cooling the motor and preventing its temperature rise. As compared to oil-based phase change materials, these materials have a higher melting point and thermal conductivity. The flow field and transient heat conduction are simulated using the finite volume method. The accuracy of numerical values obtained from the simulation of the phase change materials is validated. The sensitivity of the numerical results to the number of computational elements and time step value is assessed. The main goal of adopting the phase change material based passive cooling system is to maintain the operational motor temperature in the allowed range for applications with high and repetitive peak power demands such as electric vehicles by using phase change materials in cooling channels twisted around the motor. Moreover, this study investigates the effect of the phase change material container arrangement on the cooling performance of the under study cooling system.

Preparation and Properties of Phase Change Thermal Insulation Materials

2018 ◽  
Vol 281 ◽  
pp. 131-136
Author(s):  
Shi Chao Zhang ◽  
Wei Wu ◽  
Yu Feng Chen ◽  
Liu Shi Tao ◽  
Kai Fang ◽  
...  
Keyword(s):  
Phase Change ◽  
Thermal Insulation ◽  
Calcium Silicate ◽  
Phase Change Materials ◽  
Performance Test ◽  
Thermal Protection ◽  
Insulation Material ◽  
Insulation Materials ◽  
Short Time ◽  
Change Material

With the increase of the speed of vehicle, the thermal protection system of its powerplant requires higher insulation materials. Phase change materials can absorb large amounts of heat in short time. So the introduction of phase change materials in thermal insulation materials can achieve efficient insulation in a limited space for a short time. In this paper, a new phase change thermal insulation material was prepared by pressure molding with microporous calcium silicate as matrix and Li2CO3 as phase change material. The morphology stability, exudation and heat insulation of the materials were tested. The results show that the porous structure of microporous calcium silicate has a good encapsulation when the phase transition of Li2CO3 is changed into liquid. And the material has no leakage during use. The thermal performance test also shows that the insulation performance of the material has obvious advantages in the short term application.

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