• 한국초전도ㆍ저온공학회논문지
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• 제14권2호
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• pp.32-35
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• 2012

The objective of the present work is to develop a precise instrument for measuring the thermal property of insulating material over a temperature range from 30 K to near room temperature by utilizing a cryocooler. The instrument consists of two thermal links, a test sample, heat sink, heat source and vacuum vessel. The cold head of the cryocooler as a heat sink is thermally anchored to the thermal link and used to bring the apparatus to a desired temperature in a vacuum chamber. An electric heater as a heat source is placed in the middle of test sample for generating uniform heat flux. The entire apparatus is covered by thermal shields and wrapped in multi-layer insulation to minimize thermal radiation in a vacuum chamber. For a supplied heat flux the temperature distribution in the insulating material is measured in steady and transient state. The thermal conductivity of insulating material is measured from temperature difference for a given heat flux. In addition, the specific heat of insulating material is obtained by solving one-dimensional heat diffusion equation.

• 전기학회논문지
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• 제59권10호
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• pp.1832-1838
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• 2010

Aging of transformer insulating material in natural ester insulating oil is compared to that in conventional transformer oil. Aging of insulating paper and insulating oil have been studied by performing accelerated thermal aging test. Sealed aging test vessels containing cooper, laminated core, Kraft paper and insulating oil(natural oil or mineral oil) were aged at $140^{\circ}C$ for 500, 1000, 1500 and 2000 hours. Insulating oils after aging are investigated with total acid number, breakdown voltage and viscosity. Also, degradation of insulating paper after aging is determined using breakdown voltage and mechanical strength. Accelerated aging studies demonstrate a slower aging rate for natural ester insulating oil compared to the rate for conventional mineral oil.

• 토지주택연구
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• 제15권3호
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• pp.189-198
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• 2024

본 연구는 펄라이트와 EPS Beads를 활용한 단열 콘크리트의 열전도율과 구조적 특성을 분석하고, 물 흡수와 단열 성능 간의 상관관계를 규명하였다. 실험 결과, EPS Beads의 함유량이 4.2%일 때 가장 낮은 열전도율을 나타냈으며, 펄라이트의 함유량 증가에도 불구하고 열전도율의 변화가 나타나지 않았음을 확인하였다. 또한, 단열 콘크리트의 물 흡수를 최소화하는 것이 단열 성능 향상에 중요한 요소임을 발견하였으며, 이를 통해 도시의 탄소 중립 실현에 기여할 수 있음을 제시하였다. 이 연구는 지속 가능한 건축 재료 개발과 에너지 효율 향상에 기여할 수 있는 중요한 시사점을 제공한다.

• 한국건설순환자원학회논문집
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• 제9권4호
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• pp.642-649
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• 2021

건축물의 에너지 절약기준이 강화되면서 외단열 공법의 적용과 단열재 두께가 증가하고 있다. 유기계 단열재는 시공성, 경제성 등 시공비용 절감 효과와 뛰어난 단열성능을 가지고 있다. 하지만, 유기계 단열재 특성상 열에 매우 취약하므로 화재 발생 시 급격한 화재확산과 유독가스 발생으로 심각한 피해가 발생한다. 무기계 단열재는 기본적으로 불연성능을 가지나 무겁고 유기계 단열재에 비해 단열성능이 떨어진다. 글라스 버블은 소다 라임 보로실리케이트 유리로 밀도가 매우 낮고, 내부가 비어 있는 구형의 입자로 볼베어링 효과로 유동성이 개선된다. 또한, 무기계 단열재에 혼입하여 사용할 경우 밀도와 단열성능이 개선된다. 본 연구는 시멘트계 재료와 글라스 버블을 혼합하여 무기 단열재를 제조하였고 단열, 난연 및 불연성능을 평가하였다. 연구 결과, 글라스 버블의 혼입률이 증가할수록 열린 기공을 형성하고 있으나, 기공 및 셀 벽에 분포됨에 따라 충분한 단열성능을 보인다. 또한, 글라스 버블의 혼입률은 10% 이하로 사용하는 것이 바람직하다.

• 한국화재소방학회논문지
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• 제23권2호
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• pp.62-66
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• 2009

본 연구는 국내에서 사용되고 있는 누전차단기 외함 절연재료의 소손 특성에 대하여 연구하였다. 시료는 3개 제조사의 누전차단기 외함 절연재료를 사용하였으며, 시료의 열분해특성, 연소특성, 트래킹 특성 등을 비교 분석하였다. 열분해특성은 TGA를 사용하였으며, 연소특성은 ISO5660(Fire Tests - Reaction to Fire, part 1)을 만족하는 Mass Loss Calorimeter(FTT 사)를 사용하였고, 트래킹 특성은 고체 절연재료의 내트래킹 및 비교트래킹 지수를 측정하는 실험인 KSC IEC 60112.의 기준에 따라 분석하였다. 연구결과 A제조사의 경우 내트래킹성이 가장 우수하였고, B제조사의 경우 내트래킹성이 가장 낮은 반면 $350^{\circ}C$ 이상의 고온에서 열안정성이 가장 우수하였으며, C제조사의 경우 $400^{\circ}C$ 이하의 온도에서 열안정성이 가장 우수한 것을 알 수 있었다.

• KIEAE Journal
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• 제15권6호
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• pp.11-18
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• 2015

Purpose: The current study analyzed trends in thermal insulation performance with aging, and condensation characteristics caused by the former. Method: Thermal insulation and condensation prevention performance of an architecture were assessed using Temperature Difference Ration Inside, or TDRi. Subjects of this quantitative analysis in thermal insulation performance change due to aging included recently constructed apartments and aged apartments older than 40 years. Time series comparison and analysis were conducted to observed changes in the thermal insulation performance and condensation characteristics. Result: Analysis showed that wall insulation performance degraded with aging regardless of fortified insulating material usage or insulating material type, which caused increased danger of condensation. In addition, when fortified insulating material was installed on the connection between the walls, insulation performance degradation was lower compared to cases in which fortified materials were not used. In all cases from 1 to 10, the rate of thermal insulation performance degradation increased after 20 years of aging.

• 한국의류학회지
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• 제13권3호
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• pp.295-303
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• 1989

This study is to measure the thermal resistance of 7 types of Parka of different materials with thermal manikin and to compare their effects on physiological responses & subjective wear sensations. Following are the results obtained from the experiments 1) From the thermal manikin experiment, i) As an outer layer, although not significant, water proof fabric was warmer than water proof-vapor permeable fabric. ii) In case of insulating material, down was better for thermal resistance than polyester wadding of the same thickness. Moreover, as the down was thicker, it had more efficiency in thermal resistance. However, the marginal efficiency of thickness was found to be decreasing. 2) From the male-subject experiments, i) Chest temperature, mean skin temperature & microclimate temperature showed the same results on thermal resistance as those of the thermal manikin experiment. ii) Only during rest periods, there was a significant difference among 5 insulating materials in the sense of microclimate humidity. The almost same conclusion was obtained from the above experiments. Even the outer layer did not significantly affect thermal resistance & subjective wear sensation, insulating materials had a significant influence upon them. But in case of 3.5 cm down, it gave less comfortable than that of the thinner. Therefore the optional one for the best comfort & thermal resistance among 7 combinatins is the outer layer of water proff-vapor permeable & insulating material of 2.1 cm down.

• Elastomers and Composites
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• 제46권1호
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• pp.29-36
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• 2011

단열재(thermal insulating materials)는 외부의 온도에 저항하여 내부의 열 손실이나 외부로의 열 방출을 최소화 하기 위한 재료로 열의 전도, 복사, 대류 현상을 최소화 하여 기계의 효율을 높일 수 있는 재료를 말한다. 이러한 단열재는 건축 산업을 비롯하여 자동차, 우주 항공 및 석유화학 등 수 많은 분야에 다양하게 사용되고 있다. 특히 실리카 에어로젤은 어떤 고체보다 낮은 열전도율로 인해 열차단제로 많이 사용되어 왔다. 하지만 낮은 기계적 강도로 인해 기존의 소재를 대체하는데 있어 문제점이 있다. 본고에서는 단열재에 대해 소개하고 최근 각광을 받고 있는 열 차단소재로의 실리카 에어로젤에 대해 다룬다.

• 한국환경복원기술학회지
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• 제7권1호
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• pp.1-9
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• 2004

Caused on the excessive heat accumulation of concrete material, the indoor thermal environment of reinforced concrete building is so bad in Okinawa. As the interruption of solar radiation could be one of the methods to improve it, the purpose of this study is to find out the effect of adopting solar radiation interrupting materials -Solar insulating block, Grass, and both of them- for the improvement of thermal environment. As the result, it was found that grass on the solar insulating block which has an air layer obviously improved the indoor thermal environment of RC building which was applied to. And it was found that the systems have an effectuality on heat island phenomenon simultaneously. It could be proposed as a good system which improve the indoor thermal environment of the existent houses.

• Journal of Ceramic Processing Research
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• 제19권5호
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• pp.428-433
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• 2018

In this study, using the pilot plant activation system, the activated cement has been manufactured and then applied to the manufacturing process of mineral hydrate insulating material. The fineness of the activated cement is controlled at $5,000cm^2/g$ and $7,500cm^2/g$ and the features of mineral hydrate insulating material, using OPC and the activated cement for each degree of fineness, has been analyzed. As the result of analyzing the crystal habit of the manufactured mineral hydrate insulting material, it is analyzed that the main crystal phase of specimen is tobermorite and some quartz peak has been detected. As the degree of fineness of the activated cement increases, the height of bubble of slurry increases as well, whereas the tendency for the density character to decrease has been detected. Along with it, as the density character decreases, the compression strength has decreases, whereas the tendency for the thermal characteristic to increases has been detected. The main features of mineral hydrate insulating material, using the activated cement with the fineness of $7,500cm^2/g$, the compression strength of 0.36 MPa, and the thermal conductivity of $0.044W/m{\cdot}K$, presents the excellent features as insulation.