• Title/Summary/Keyword: Micro-encapsulated phase-change material

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Phase-change Temperature of Micro-encapsulated Phase-change Material (미립 피복 상변화 물질의 상변화 온도에 대한 연구)

  • 최은수
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.14 no.2
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    • pp.168-174
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    • 2002
  • In order to obtain a new heat transfer fluid having a high thermal capacity, micro-capsules of a phase-change material can be a successful candidate to be added into water. In this study, 25, 50, 100, and $200\mu$m diameter micro-encapsulated Lauric acids were tested by a differential scanning calorimeter. The Lauric acid itself had a single freezing curve, but the micro-encapsulated Lauric acid had double freezing curves. The second freezing dominated for $25\mu$m diameter Lauric acids. But the first freeing energy became big as the size of the capsule increased.

Heat Transfer Characteristics of Micro-encapsulated Phase-Change-Material Slurry (잠열 마이크로캡슐 슬러리의 열전달 특성)

  • Kim, Myoung-Jun;Park, Ki-Won
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.18 no.6
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    • pp.518-525
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    • 2006
  • The present experiments have been performed for obtaining the melting heat transfer characteristics of micro-encapsulated solid-liquid phase-change material and water mixture slurry flow in a circular tube heated with constant wall heat flux. The phase change material having a low melting point was selected for a domestic cooling system in the present study. The governing parameters were found to be latent heat material concentration, heat flux, and the slurry velocity. The experimental results revealed that the increase of tube wall temperature of latent microcapsule slurry was lower than that of water caused by the heat absorption of fusion.

Heat Transfer Characteristics of Micro-encapsulated Phase Change Material Slurry (잠열 마이크로캡슐 슬러리의 열전달 특성)

  • Park, Ki-Won;Kim, Myoung-Jun
    • Proceedings of the SAREK Conference
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    • 2005.11a
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    • pp.193-198
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    • 2005
  • The present experiments have been performed for obtaining the melting heat transfer characteristics of micro-encapsulated solid-liquid phase change material and water mixed slurry flow in a circular tube heated with constant wall heat flux. The phase change material having a low melting point was selected for a domestic cooling system in the present study. The governing parameters were found to be latent heat material concentration, heat flux, and the slurry velocity. The experimental results revealed that the increase of tube wall temperature of latent microcapsule slurry was lower than that of water caused by the heat absorption of fusion.

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Enhancement of Convective Heat Transfer by Using a Micro-Encapsulated Phase-Change-Material Slurry (피복된 미립 상변화물질 슬러리를 이용한 대류 열전달의 향상에 관한 연구)

  • Jung, Dong-Ju;Choi, Eun-Soo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.9
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    • pp.1277-1284
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    • 2000
  • To enhance heat transfer characteristics of water, micro-encapsulated octadecane of about $10{\mu}m$ diameter was added to water. Viscosity of the slurry was measured by using a capillary tube viscometer. The measured viscosity decreased as the temperature of the slurry increased, and it increased as the fraction of the capsules in the slurry increased. Thermal characteristics of the octadecane were studied by using a differential scanning calorimeter. The melting temperature and the melting energy of the octadecane were found to be $28.6^{\circ}$ and 34.4kcal/kg, respectively. The convective heat transfer characteristics of the slurry were investigated in a flow loop with a constant heat flux test section. Friction factor of the slurry flow was found to be similar to the expected curve by Petukhov. The Nusselt number of the slurry flow was highest when the octadecane melted. Effective thermal capacity of the 14.2% slurry was found to have 1.67 times of the thermal capacity of water.

Preparation of Polyurea Microcapsules Containing Phase Change Material and their Application on Fiber Composites (상전이물질을 함유한 폴리우레아 마이크로캡슐의 제조와 섬유복합소재에의 적용)

  • Kim, Hea-In;Jin, Xuan-Zhen;Choi, Hae-Wook;Park, Soo-Min
    • Textile Coloration and Finishing
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    • v.19 no.1 s.92
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    • pp.37-44
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    • 2007
  • In this study, for textile use, the octadecane of phase change materials(PCM) was encapsulated in several micro-diameter shell which prevents leakage of the material during its liquid phase. Microencapsulated PCM(PM) was prepared with the different weight ratio of core material to wall material and by interfacial polymerization methods using polyurea as shell material. Phase stability for O/W emulsion of PCM and PVA aq. (PE) was evaluated by Turbiscan Lab. The capsule formation win identified using FT-IR. Physical properties of microcapsules including diameter, particle distribution, morphology were investigated. Thermal transport properties of suede treated with PM(SPM) were determined by KES-F7 system.

An experimental study on thermal performance evaluation of PCM mixed coating material constructed in and out of the wall (벽체 내·외부에 시공한 PCM혼입 도료의 열적성능 평가에 관한 실험적 연구)

  • Ju, Dong-Uk;Shin, Sang-Heon;Lee, Han-Seung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2014.05a
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    • pp.216-217
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    • 2014
  • Optimum finishing position, thickness and phase change temperature of winter and summer season were selected and suitability of finishing materials was evaluated based on temperature measurement of specimens applying the coating material mixed phase change materials(PCM). As a result, when finishing position was interior and finishing thickness of coating material mixed n-Octadecane(28℃ PCM) was 4mm, thermal performance was effective. n-Octadecane in summer season and n-Hexadecane(18℃ PCM) in winter season are indicated effective on energy savings, respectively.

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Physical Properties of Microencapsulated Phase Change Material Slurries (미립잠열슬러리의 물성에 관한 실험적 연구)

  • 이효진;홍재창;이재구
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.12 no.9
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    • pp.860-869
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    • 2000
  • The thermal conductivity and density of slurries entrained with the particles of Micro-PCM are measured with respect to its temperatures as well as concentrations. For the thermal conductivity of slurries, a device made from P.A. Hilton (Model No. H470) is adopted. There is a well-scaled 0.3 mm gap between shells into which the slurry is injected. The temperatures of the slurry are changed to $5~25^{\circ}C$ , for which it is controled by the supplied voltage and cooling water circulated around the outer shell. The concentrations of Micro-PCM slurries are varied from 5 wt% to 50 wt%. Some general equations such as Maxwell's equation, are evaluated for their applicability with Micro-PCM slurry. As a result, it happens to be some 20% discrepancy between the experiment and the applied equations. The density measurements of Micro-PCM slurry to its temperature and concentration are peformed by hydrometer. For the experiment, tetradecane encapsulated slurry (($t_m≒6^{\circ}C$) and a mixed wax ($t_m≒50^{\circ}C$) are tested. The temperature changes of tetradecane are applied for $0^{\circ}C\;to\;$20^{\circ}C$and a mixed wax for $20^{\circ}C\;to\;$60^{\circ}C$ and its concentrations are changed from 5 wt% to 30 wt%. The results are compared with a general equation and the referenced data. For the conclusion, the experimental result and a general equation are well agreed.

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The Analysis of the Energy Saving Performances of Building Materials using Phase Change Materials (상변화물질을 적용한 건축자재의 에너지절약 가능성 분석)

  • An, Sang-Min;Hwang, Suck-Ho;Kim, Tae-Yeon;Leigh, Seung-Bok
    • 한국태양에너지학회:학술대회논문집
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    • 2011.04a
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    • pp.162-167
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    • 2011
  • Thermal storage plays an important role in building energy saving, which is greatly assisted by the incorporation of latent heat storage in building materials. A phase change material is a substance with a high heat of fusion which, melting and solidifying at a certain temperature, can be storing and releasing large amount of energy. Heat is stored or released when the material changes from solid to liquid. Integration of building materials incorporating PCMs into the building envelope can result in increased efficiency of the built environment. The aim of this research is to identify thermal performance of PCMs impregnated building materials which is applied to interior of building such as gypsum and red clay. In order to analyze thermal performance of phase change materials, test-cell experiments and simulation analysis were carried out. The results show that micro-encapsulated PCM has an effect to maintain a constant indoor temperature using latent heat through the test-cell experiments. PCM wallboard makes it possible to reduce the fluctuation of room temperature and heating and cooling load by using EnergyPlus simulation program. Phase change material can store solar energy directly in buildings. Increasing the heat capacity of a building is capable of improving human comfort by decreasing the frequency of indoor air temperature swings so that the interior air temperature is closer to the desired temperature for a long period of time.

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