• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2019년도 추계 학술논문 발표대회
• /
• pp.130-131
• /
• 2019

As part of recent low-energy policies, thermal insulation standards for buildings are being tightened every year. In addition, the conventional styrofoam insulating material has a problem that the thickness of the heat insulating material to achieve a standard heat permeability is rapidly increased. Due to the thick insulation, there is a high risk of spreading vulnerable structures such as fire due to lack of space between buildings. On the other hand, the method of using the insulation as a formwork is known to be excellent cost saving effect through the reduction of the formwork usage and the simplification of the external insulation work. In order to solve this problem, this study aims to fabricate a multi-layered insulator that combines high-performance phenolic foam insulation and styrofoam insulation and evaluate the deflection characteristics for use as formwork.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2009년도 제40회 하계학술대회
• /
• pp.2061_2062
• /
• 2009

Within serviced period of time in transformer, thermal stress is the most influential parameter affecting the aging behavior of an insulation system. The thermal stress on the insulation system may occur from operation in a high temperature environment due to Joule's heat at winding coils. This paper describes a development of capacitive sensor and preventive diagnosis techniques for electrical insulating oil, widely used for power and distribution transformer. To survey the dielectric properties of the virgin and used mineral insulating oil, we utilized the highly precise measuring system of KRISS. And the results were used to determine the design factors of the sensor. To evaluate diagnosis by the sensor, we performed accelerated aging test about insulating oils. The condition of aged specimens were investigated by measurements of relative permittivity i.e. capacitance change by capacitive sensor.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2016년도 춘계 학술논문 발표대회
• /
• pp.221-222
• /
• 2016

The replacement ratio of waste EPS was varied, and its effect on compressive strength and absorption capacity was investigated. According to the experimental results, The 28th day compressive strengths for the W/C 50% specimens were 17.5~21.2MPa, which was relatively low compared to the 13.6~22.2MPa of the W/C 70%.

• 한국화재소방학회:학술대회논문집
• /
• 한국화재소방학회 2003년도 춘계학술논문발표회논문집
• /
• pp.164-170
• /
• 2003

In this paper, we studied on the firing characteristics and electrical fire analysis of power cord deteriorated by thermal stress. The cross section of PVC insulating cord deteriorated by indirect flame decreased through heat convection. PVC insulating cord deteriorated by direct flame was bumpy shape. The exothermic peak of normal cord was shown at ($526.7^{\circ}C$), but the peaks or on(heat treatment temperature) ($150^{\circ}C$) cord was shown at ($299.6^{\circ}C$) and [$502.2^{\circ}C$]. The exothermic peaks according to high temperature were similar to those of amorphous carbon. In the FT-IR analysis, the absorption peak of normal cord indicated double bond of oxygen and carbon in benzene ring at 1720.0$cm^{1}$. As the HTT was high, the height of characteristic peak decreased and the peak of carbonyl group was shown at about 1625.7$cm^{-1}$. The characteristic peak of single bond(O-H) was shown at about 3479.2$cm^{-1}$. In case of the internal part of wire covering deteriorated by over current, the characteristic peak were shown at about 3417.3$cm^{-1}$ and 1600.2$cm^{-1}$. The above results show that we can distinguish the differences according to the fire pattern through the internalㆍexternal analysis of wire covering deteriorated by heat.

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

• 생물환경조절학회지
• /
• 제28권3호
• /
• pp.273-278
• /
• 2019

본 연구는 최근 신소재 단열재로 주목받고 있는 실리카 에어로겔을 이용하여 현재 사용되고 있는 다겹보온커튼의 단점을 보완하고 보온성을 유지 및 향상 시킬 수 있는 새로운 조합의 다겹보온커튼을 제작 하고, 보온 특성을 분석하고자 한다. 실험에 사용된 다겹보온커튼은 에어로겔이 함유된 부직포를 사용하여 총 6가지의 조합으로 제작하였으며 중량, 두께 및 온도변화에 따른 열유속을 측정하여 비교분석하였다. 실험결과 조합별 보온커튼의 열유속은 마트지+에어로겔 멜트블로운+발포 에어로겔 부직포+에어로겔 멜트블로운+마트지 조합이 가장 낮게 측정되었다. 열유속은 단위면적당 단위시간에 통과하는 열량을 뜻하며 수치가 높을수록 다겹보온커튼을 통과하는 열량이 많다는 것을 의미하여 보온성이 낮다고 판단할 수 있다. 조합형 보온커튼의 무게와 두께는 보온성과 상관이 높은 것으로 나타났으며, 특히 에어로겔 멜트블로운 부직포가 조합된 보온커튼이 같은 매수의 단열재가 조합된 보온커튼에 비해 보온성이 상대적으로 높게 나타났다. 하지만 에어로겔 멜트블로운 부직포는 내광성과 내구성이 약하고, 까다로운 제작공정과 에어로겔이 비산하는 문제점이 있다. 이러한 문제점을 해결하기 위하여 비교적 제작공정이 단순하고 보온성이 우수한 중공사 부직포와 에어로겔 발포 부직포를 조합한 다겹보온커튼이 실제 농가에서 사용하기에 적합하다고 판단된다.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2006년도 추계 학술논문 발표대회 논문집
• /
• pp.5-8
• /
• 2006

This study investigates the field application, Songdo the # 1st WORLD, on zero-crack construction of the fundamental mass concrete using double bubble sheets and applying low heat mixture. Experimental results of hydration heat analysis showed that crack modulus of concrete incorporating 20% of blast furnace slag cement was 1.0 in 120 hours, representing 50% probability of crack occurrence, thus requiring additional measures. As for a curing method, a specimen insulating two layers of vinyl chloride+double bubble sheets exhibited only $16.5^{\circ}C$ difference between upper and lower sections, and it also showed favorable workability as well as competitive economic side. Therefore it was determined to use it for curing method in this field. For the curing results of practical field, using 2 layers of vinyl chloride+double bubble sheets and applying low heat mixture on the fundamental mass concrete in 3A residential building exhibited less than only $15^{\circ}C$ difference between surface and center section of that in 5 days elapse and less than $20^{\circ}C$ in 9 days. This means that the crack by hydration heat was prevented, and other fields structures also resisted the plastic shrinkage by insulating the vinyl, sinking crack by second temping, even drying shrinkage by the mixture of low unit water. Therefore the crack on the placement has not been found so far, since the construction was started before 6 month.

• 한국의류학회지
• /
• 제20권4호
• /
• pp.647-654
• /
• 1996

The purpose of this study was to analyze the effect of fiber type, compressional resilience and moisture transport properties of wool and polyester fiber on the heat transfer of insulation nonwovens. The results obtained were as follows: 1) Overall heat transfer of wool nonwoven was slightly higher than that of polyester nonwovens. Warmability of wool nonwoven was lower than that of polyester nonwovens. The radiative heat transfer was in the range of 11~18% of overall heat transfer in polyester nonwovens and 25% in wool nonwoven. 2) As wool nonwoven compressed, overall heat transfer was increased by increasing radiative heat transfer and wamability was decreased due to the poor compressional resilience. 3) Increasing rate of heat transfer by moisture absorption in wool nonwoven was lower than that of polyester nonwovens. Thickness and compressional resilience of wool nonwoven were reduced extremely by moisture absorption.

• 한국의류학회지
• /
• 제18권2호
• /
• pp.244-251
• /
• 1994

The purpose of this study was to analyze conductive convective and radiative heat transfer characteristic of the nonwovens were studied by measuring thermal conductance at atmospheric and low air pressure. The results obtained were as follows . 1) As thickness of air layer Increased, overall heat transfer was decreased by reducing conductive and radiative heat trasfer. 2) The conductive and convective heat trasfer by air were in the range of 79~8971 of overall heat transfer. 3) As thickness of nonwoven increased for a given solidity, overall heat trasfer was decresed by increasing total thickness of air layer and by reducing conductive and radiative heat transfer. 4) For a given weight, increasing thickness is more effective than increasing solidity.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2008년도 추계 학술발표회
• /
• pp.1638-1646
• /
• 2008

This paper presents a series of numerical simulations on the thermal performance and sectional efficiency of a closed-loop vertical ground heat exchanger (U-loop) equipped in a geothermal heat pump system (GHP). A 2-D finite element analysis, ANSYS, was employed to evaluate the temperature distribution on the borehole cross section involving HDPE pipe/grout/soil formation to compare the sectional efficiency between the conventional U-loop and a new latticed HDPE pipe system which is equipped with a thermally insulating latice in order to reduce thermal interference between the inflow and outflow pipes. In addition, a 3-D finite volume analysis (Fluent) was used to simulate the operating process of the closed-loop vertical ground heat exchanger by considering the effect of grout's thermal properties, rate of circulation pump, distance between the inflow and outflow pipes, and the effectiveness of the latticed HDPE pipe system. It was observed that the thermal interference between the two strands of U-loop is of importance in determining the efficiency of the ground heat exchanger, and thus it is highly recommendable to modify the cross section configuration of the conventional U-loop system by including a thermally insulating latice between the two strands.