• 제목/요약/키워드: phase change materials

검색결과 827건 처리시간 0.023초

High School Exploration of a Phase Change Material as a Thermal Energy Storage

  • Ardnaree, Kwanhathai;Triampo, Darapond;Yodyingyong, Supan
    • 대한화학회지
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    • 제65권2호
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    • pp.145-150
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    • 2021
  • The present study describes a hands-on experiment to help students understand the concept of phase change or phase transition and its application in a phase change material (PCM). PCMs are substances that have the capability of storing and releasing large amounts of thermal energy. They act as energy storage materials that provide an effective way to save energy by reducing the electricity required for heating and cooling. Lauric acid (LA) was selected as an example of the PCM. Students investigated the temperature change of LA and the temperature (of air) inside the test tube. The differences in the temperatures of the systems helped students understand how PCMs work. A one-group pretest and posttest design was implemented with 34 grade-11 students in science and mathematics. Students' understanding was assessed using a multiple-choice test and a questionnaire. The findings revealed that the designed activity helped students understand the concept of phase change and its application to materials for thermal energy storage.

상변화 물질의 상변이 촉진에 관한 실험적 연구 (Experimental Study on Accelerating Phase Change Heat Transfer)

  • 박설현;오율권;차경옥
    • Journal of Advanced Marine Engineering and Technology
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    • 제26권1호
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    • pp.23-29
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    • 2002
  • Solid-liquid phase change (i.e. melting or solidification) occurs in a number of situations of practical interest. Some common examples include the melting of edible oil, metallurgical process such as casting and welding, and materials science applications such as crystal growth. Therefore, due to the practical importance of the subject, there have been a large number of experimental and numerical studies of problems involving phase change during the past few decades. Also, this study presented the effective way to enhance phase change heat transfer.

상 변화와 인터페이스 이론을 이용한 고에너지물질의 반응연구 (Study of energetic materials using phase change and interface theory)

  • 김기홍;김학준;김형원;여재익
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2008년도 제31회 추계학술대회논문집
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    • pp.60-63
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    • 2008
  • 고에너지 물질의 상변화는 연소과정에서 발생하는 필연적으로 중요한 요소이다. 연소과정에서 발생한 고온, 고압의 가스는 주변의 물질과 상호작용을 통해 복잡한 현상을 일으키게 된다. 본 연구에서는 고에너지 물질의 상변화를 해석을 하기 위한 기초 연구로 상변화 변수를 이용하여, 증기 폭발을 해석하였다.

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GeSbTe계 이중층의 상변화 특성에 미치는 열처리 온도 효과 (Effect of Annealing Temperature on Phase-change Characteristics of GeSbTe-based Bilayers)

  • 윤회진;방기수;이승윤
    • 한국전기전자재료학회논문지
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    • 제30권2호
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    • pp.86-90
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    • 2017
  • This work reports the phase-change behavior and thermal stability of doped GeSbTe/GeSbTe bilayers. We prepared the bilayers using RF sputtering, and annealed them at annealing temperature ranging from $100^{\circ}C$ to $400^{\circ}C$. The sheet resistance of the bilayer decreased and saturated with increasing annealing temperature, and the saturated value was close to that of pure GeSbTe film. The surface of the bilayer roughened at $400^{\circ}C$, which corresponds to the surface roughening of doped GeSbTe film. Mixed phases of face-centered cubic and hexagonal close-packed crystalline structures were identified in the bilayers annealed at elevated temperature. These results indicate that the phase-change behavior of the bilayer depends on the concurrent phase-transitions of the two GeSbTe-based films. The dopants in the doped GeSbTe film were diffused out at annealing temperatures of $300^{\circ}C$ or higher, which implies that the thermal stability of the bilayer should be considered for its application in phase-change electronic devices.

2-PCM 잠열축열 시스템의 열역학적 성능 (Thermodynamic performance of 2-PCM latent heat thermal energy storage system)

  • 이세균;우정선;이재효;김한덕
    • 설비공학논문집
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    • 제12권2호
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    • pp.189-199
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    • 2000
  • This paper investigates the thermodynamic performance of latent heat thermal energy storage system using two phase change materials(2-PCM system). The thermodynamic merit of using 2-PCM is clear in terms of exergetic efficiency, which is substantially higher than that of 1-PCM system. Optimum phase change temperature to maximize the exergetic efficiency exists for each case. The heat transfer area ratio of high temperature storage unit, X, becomes another important parameter for 2-PCM system if the phase change temperatures of given materials are different from those of optimum conditions. It is a good approximation for X$_{opt}$ to be 0.5 when optimum phase change temperatures are used. Otherwise X$_{opt}$ is determined differently as a function of given phase change temperatures.res.

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$Ge_2Sb_2Te_5$ 상변화 소자의 상부구조 변화에 따른 결정화 특성 연구 (A study on characteristics of crystallization according to changes of top structure with phase change memory cell of $Ge_2Sb_2Te_5$)

  • 이재민;신경;최혁;정홍배
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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    • pp.80-81
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    • 2005
  • Chalcogenide phase change memory has high performance to be next generation memory, because it is a nonvolatile memory processing high programming speed, low programming voltage, high sensing margin, low consumption and long cycle duration. We have developed a sample of PRAM with thermal protected layer. We have investigated the phase transition behaviors in function of process factor including thermal protect layer. As a result, we have observed that set voltage and duration of protect layer are more improved than no protect layer.

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The Study of Phase-change with Temperature and Electric field in Chalcogenide Thin Film

  • Yang, Sung-Jun;Shin, Kyung;Park, Jung-Il;Lee, Ki-Nam;Chung, Hong-Bay
    • Transactions on Electrical and Electronic Materials
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    • 제4권5호
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    • pp.24-27
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    • 2003
  • We have been investigated phase-change with temperature and electric field in chalcogenide Ge$_2$Sb$_2$Te$\sub$5/ thin film. T$\sub$c/(crystallization temperature) is confirmed by measuring the resistance with the varying temperature on the hotplate. We have measured I-V characteristics with Ge$_2$Sb$_2$Te$\sub$5/ chalcogenide thin film. It is compared with I-V characteristics after impress the variable pulse. The pulse has variable height and duration.

칼코게나이드 다층박막의 상변화 특성에 관한 연구 (A Study on Characteristics of Phase Change in Chalcogenide Multilayered Thin Film)

  • 최혁;김현구;정홍배
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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    • pp.1426-1427
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    • 2006
  • Chalcogenide based phase-change memory has a high capability and potential for the next generation nonvolatile memory device. Fast writing speed, low writing voltage, high sensing margin, low power consume and long cycle of read/write repeatability are also good advantages of nonvolatile phase-change memory. We have been investigated the new material for the phase-change memory. Its composition is consists of chalcogenide $Ge_{1}Se_{1}Te_2$ material. We made this new material to solve problems of conventional phase-change memory which has disadvantage of high power consume and high writing voltage. In the present work, we are manufactured $Ge_{1}Se_{1}Te_{2}/Ge_{2}Sb_{2}Te_{5}/Ge_{1}Se_{1}Te_{2}$ and $Ge_{2}Sb_{2}Te_{5}/Ge_{1}Se_{1}Te_{2}/Ge_{2}Sb_{2}Te_{5}$ sandwich triple layer structure devices are manufactured to investigate its electrical properties. Through the present work, we are willing to ensure a potential of substitutional method to overcome a crystallization problem on PRAM device.

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비정질 $Ge_1Se_1Te_2$$Ge_2Se_2Te_5$ 칼코게나이드박막의 상변화특성 (Phase change properties of amorphous $Ge_1Se_1Te_2$ and $Ge_2Se_2Te_5$ chalcogenide thin films.)

  • 정홍배;조원주;구상모
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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    • pp.118-119
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    • 2006
  • In the present work, we investigate the basic physical and thermal properties and electrical resistance change due to phase change in chalcogenide-based $Ge_1Se_1Te_2$ and $Ge_2Se_2Te_5$ thin films. The phase transition from amorphous to crystalline states, and vice versa, of $Ge_1Se_1Te_2$ and $Ge_2Se_2Te_5$ thin films by applying electrical pulses have been studied. The reversible phase transition between the amorphous and crystalline states, which is accompanied by a considerable change in electrical resistivity, is exploited as means to store bits of information.

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상변화물질을 활용한 원통형 리튬이온 배터리 셀의 냉각성능 및 등온유지성에 관한 연구 (Study on cooling performance and isothermal maintenance of cylindrical type lithium-ion battery cell using phase change material)

  • 윤재형;현수웅;정희준;신동호
    • 한국가시화정보학회지
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    • 제21권2호
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    • pp.34-45
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    • 2023
  • When lithium-ion batteries operate out of the proper temperature range, their performance can be significantly degraded and safety issues such as thermal runaway can occur. Therefore, battery thermal management systems are widely researched to maintain the temperature of Li-ion battery cells within the proper temperature range during the charging and discharging process. This study investigates the cooling performance and isothermal maintenance of cooling materials by measuring the surface temperature of a battery cell with or without cooling materials, such as silicone oil, thermal adhesive, and phase change materials during discharge process of battery by the experimental and numerical analysis. As a result of the experiment, the battery pack filled with phase change material showed a temperature reduction of 47.4 ℃ compared to the case of natural convection. It proves the advanced utility of the cooling unit using phase change material that is suitable for use in battery thermal management systems.