scholarly journals Thermal conductivity of aerated concrete (AC) composites containing micro-encapsulated phase change materials

2019 ◽  
Vol 282 ◽  
pp. 02033
Author(s):  
Shuai-Qi Tian ◽  
Ming-Liang Qu ◽  
Li-Wu Fan ◽  
Zi-Tao Yu ◽  
Jian Ge
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Phase Change ◽  
Phase Change Materials ◽  
Storage Capacity ◽  
Volumetric Heat Capacity ◽  
Liquid Phases ◽  
Aerated Concrete ◽  
Insulation Performance ◽  
Composite Samples

Aerated concrete (AC) was incorporated with micro-encapsulated phase change materials (PCMs) to form a novel PCM-composite AC with improved thermal storage capacity. RT25 paraffin was selected as the PCM and the composite materials were prepared by adding micro-encapsulated paraffin as an ingredient at various loadings. The effective thermal conductivity of the composite samples was measured at both 17 ºC and 35 ºC, while the paraffin was in solid and liquid phases, respectively. The volumetric heat capacity of the composites were also measured. Results showed that both the thermal conductivity and volumetric heat capacity increase upon adding the micro-encapsulated paraffin. However, they were found to decrease when further increase the paraffin loading. The maximum thermal conductivity and volumetric heat capacity were enhanced by approximately 35% and 30% when the paraffin loadings were 1% wt. and 3% wt., respectively. Since the increase of thermal conductivity leads to the deterioration of the thermal insulation performance, the composite samples with 3% wt. micro-encapsulated paraffin with lower thermal conductivity but the highest volumetric heat capacity was exhibited to be more appropriate.

scholarly journals Testing a Gypsum Composite Based on Raw Gypsum with a Direct Admixture of Paraffin and Polymer to Improve Thermal Properties

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3241
Author(s):  
Krzysztof Powała ◽  
Andrzej Obraniak ◽  
Dariusz Heim
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Thermal Properties ◽  
Phase Change ◽  
Large Scale ◽  
Building Materials ◽  
Residential Buildings ◽  
Energy Performance ◽  
Polymer Content ◽  
Volumetric Heat Capacity

The implemented new legal regulations regarding thermal comfort, the energy performance of residential buildings, and proecological requirements require the design of new building materials, the use of which will improve the thermal efficiency of newly built and renovated buildings. Therefore, many companies producing building materials strive to improve the properties of their products by reducing the weight of the materials, increasing their mechanical properties, and improving their insulating properties. Currently, there are solutions in phase-change materials (PCM) production technology, such as microencapsulation, but its application on a large scale is extremely costly. This paper presents a solution to the abovementioned problem through the creation and testing of a composite, i.e., a new mixture of gypsum, paraffin, and polymer, which can be used in the production of plasterboard. The presented solution uses a material (PCM) which improves the thermal properties of the composite by taking advantage of the phase-change phenomenon. The study analyzes the influence of polymer content in the total mass of a composite in relation to its thermal conductivity, volumetric heat capacity, and diffusivity. Based on the results contained in this article, the best solution appears to be a mixture with 0.1% polymer content. It is definitely visible in the tests which use drying, hardening time, and paraffin absorption. It differs slightly from the best result in the thermal conductivity test, while it is comparable in terms of volumetric heat capacity and differs slightly from the best result in the thermal diffusivity test.

scholarly journals Thermal applications of hybrid phase change materials: A critical review

2020 ◽  
Vol 24 (3 Part B) ◽  
pp. 2151-2169 ◽  
Author(s):  
Syeda Tariq ◽  
Hafiz Ali ◽  
Muhammad Akram
Keyword(s):  
Thermal Conductivity ◽  
Energy Storage ◽  
Phase Change ◽  
Phase Change Materials ◽  
Storage Capacity ◽  
Short Review ◽  
Hybrid Form ◽  
Great Ability ◽  
Heating And Cooling ◽  
Energy Storage Capacity

Phase change materials (PCM) with their high latent heat capacity have a great ability to store energy during their phase change process. The PCM are renowned for their applications in solar and thermal energy storage systems for the purpose of heating and cooling. However, one of the major drawbacks of PCM is their low thermal conductivity due to which their charging and discharging time reduces along with the reduction in energy storage capacity. This reduction in the energy storage capacity of PCM can be improved by producing organic-inorganic hybrid form-stable PCM, with the combination of two or more PCM together to increase their energy storage capacity. Nanoparticles that possess high thermal conductivity are also doped with these hybrid PCM (HPCM)to improve the effectiveness of thermal conductivity. This paper presents a short review on the applications of HPCM in energy storage and building application. Apart from this a short section of applications of composite PCM (CPCM) is also reviewed with discussions made at the end of each section. Results from the past literature depicted that the application of these HPCM and CPCM enhanced the energy storage capacity and thermal conductivity of the base PCM and selection of a proper hybrid material plays an essential role in their stability. It is presumed that this study will provide a sagacity, to the readers, to investigate their thermophysical properties and other essential applications.

scholarly journals Evaluation of Energy Performance and Thermal Comfort Considering the Heat Storage Capacity and Thermal Conductivity of Biocomposite Phase Change Materials

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2191
Author(s):  
Su-Gwang Jeong ◽  
Taemin Lee ◽  
Jeonghun Lee
Keyword(s):  
Thermal Conductivity ◽  
Energy Consumption ◽  
Thermal Comfort ◽  
Phase Change ◽  
Chemical Stability ◽  
Phase Change Materials ◽  
Storage Capacity ◽  
Heat Storage ◽  
Building Energy ◽  
Vacuum Impregnation

The application of phase change materials (PCMs) has been verified as an effective strategy for improving energy efficiency and reducing greenhouse gas emissions. Biocomposite PCMs (Bc-PCM) exhibit large latent heat, chemical stability, and a wide temperature range. In this study, thermal conductivity improved Bc-PCM (TBc-PCM) was made via vacuum impregnation with graphene nanoplatelets (GNPs). Chemical stability analysis and thermal performance analyses of the Bc-PCM and TBc-PCM were carried out as well as building energy simulations and thermal comfort analyses. Our results show Bc-PCM showed a higher heat storage capacity and enthalpy value compared to TBc-PCM. TBc-PCM exhibited a 378% increase in thermal conductivity compared to Bc-PCM. Building energy simulation results revealed that annual heating and cooling energy consumption decreased as the thickness of the PCM layer increased. In addition, the Bc-PCM with a larger PCM capacity was more effective in reducing energy consumption during the heating period. On the other hand, the cooling energy reduction effect was greater when TBc-PCM with high thermal conductivity was applied because of the high heat transfer during the cooling period. Thermal comfort evaluation revealed it was more comfortable when PCM was applied.

scholarly journals Preparation and characterization of phase change energy storage gypsum

2020 ◽  
pp. 217-217
Author(s):  
Yichao Zhang ◽  
Ying Wang ◽  
Jinghai Zhou ◽  
Jian Huang ◽  
Xiaoxin Wu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Compressive Strength ◽  
Energy Storage ◽  
Phase Change ◽  
Phase Change Materials ◽  
Loss Rate ◽  
Thermal Conductivity Coefficient ◽  
Mass Loss Rate ◽  
Capric Acid

The thermophysical properties of binary phase change materials with different ratios of capric acid and palmitic acid were studied by step cooling curve method and differential scanning calorimetry in this paper. Furthermore, the best adsorption materials and coating materials were selected by testing their mass adsorption rate and mass loss rate. Finally, the specific heat capacity, thermal conductivity coefficient and compressive strength of phase change energy storage gypsum (PCESG) was determined respectively, and the energy-saving effect of the PCESG in the wall is evaluated. The results show that the binary phase change materials can form a eutectic system. When the mass ratio of capric acid to palmitic acid is 7:3, the low eutectic point of the binary system is formed, and the crystallization temperature of system is 26?C. The adsorption capacity of expanded perlite is much larger than that of ceramsite, and the mass loss rate of the material coated by styrene acrylic emulsion is lower than that of EVA. The specific heat capacity of PCESG is about twice that of ordinary gypsum. With the addition of phase change materials, the thermal conductivity coefficient of PCESG decreases gradually, and the compressive strength of PCESG decreases gradually at the same time. Compared with ordinary gypsum, PCESG has better energy-saving performance.

Uncertainty Analysis of Thermal Protection by Microencapsulated Phase Change Micro/Nanoparticles during Hyperthermia

2011 ◽  
Vol 291-294 ◽  
pp. 1816-1819
Author(s):  
Yong Gang Lv ◽  
Yang Zou ◽  
Li Yang
Keyword(s):  
Phase Transition ◽  
Thermal Conductivity ◽  
Heat Capacity ◽  
Phase Change ◽  
Phase Change Materials ◽  
Thermal Protection ◽  
Treatment Protocol ◽  
Lower Phase ◽  
Phase Transition Temperatures ◽  
Protection Efficacy

Uncertainties for thermal protection efficacy caused by deviations of the values of phase change materials (PCMs) properties (including conductivity, heat capacity, thermal conductivity, latent heat and phase transition temperature) were studied based on our previous study. Our results suggested that the radius of the micro/nano PCM particle, and the upper and lower phase transition temperatures of the PCM should be carefully measured before performing thermal protection by PCMs during hyperthermia. The results will further help us to enlarge the application of clinical hyperthermia in cancer treatment and optimize the treatment protocol of thermal protection by PCMs.

Temperature Dependence of Enthalpy and Heat Capacity of Alkanes and Related Phase Change Materials (PCMs) with a Peltier-element-based Adiabatic Scanning Calorimeter

MRS Advances ◽  
2016 ◽  
Vol 1 (60) ◽  
pp. 3935-3940 ◽  
Author(s):  
Jan Leys ◽  
Christ Glorieux ◽  
Jan Thoen
Keyword(s):  
Heat Capacity ◽  
Phase Change ◽  
Temperature Dependence ◽  
Phase Change Materials ◽  
Storage Capacity ◽  
Thermal Storage ◽  
Scanning Calorimetry ◽  
Peltier Element ◽  
Simulation Input ◽  
Adiabatic Scanning Calorimeter

ABSTRACTResearch in the field of phase change materials (PCMs) requires that the temperature dependence of the thermal storage capacity be well known for the selection of PCMs as well as for simulation input. A differential scanning calorimeter (DSC) is often used, but it substantially misrepresents the true heat capacity in the vicinity of large-enthalpy phase transitions. Therefore, other suitable experimental techniques should be applied for the determination of the thermal storage capacity. Peltier-element-based adiabatic scanning calorimetry (pASC) measures the heat capacity and the enthalpy of PCMs in thermodynamic equilibrium, thus removing the rate dependence and deformation that are inherent to DSC. The technique is illustrated here by measurements on the pure alkane tricosane (C23), the commercial alkane mixture RT42 and its bound counterpart PX42.

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