• 제목/요약/키워드: Insulation Assessment

검색결과 127건 처리시간 0.026초

절점망 해석프로그램을 이용한 해저터널 내 고전압 전력케이블에 의한 가스배관의 안전성 평가 연구 (A Study on the System Integrity of Gas Pipeline by High Voltage Power Line in Submarine Tunnel)

  • 배정효;하태현;이현구;김대경
    • 한국가스학회지
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    • 제5권4호
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    • pp.21-26
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    • 2001
  • 최근 국내에서는 효율적인 공간활용을 위해 해저터널을 이용하여 전력을 공급하는 것이 시도되고 있으며, 해저터널 내에 에너지 공급 기간시설물(진력케이블, 가스배관, 송유관, 지역난방배관 등)들이 같이 포설될 수 있으면 공사비 절감의 효과는 엄청날 것이므로 관심도가 높아지고 있다. 최근, 국내에서도 해저터널 내에 가스배관과 전력선이 병행 시공되는 경우가 발생하여 가스배관에 대한 안전성에 대한 평가가 요구되고 있다. 따라서 본 논문에서는 해해저터널 내 고전압 전력케이블에 의한 가스배관의 교류부식, 가스배관의 코팅과 용융. 절연 플랜지, 전기방식용 정류기 등의 전기방식설비의 안정성에 대하여 검토함으로써, 최종적으로 가스배관의 안전성을 평가$\cdot$연구하였다.

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공동주택 사용부문의 이산화탄소 배출량 추정모델 연구 (Estimation Model of the Carbon Dioxide Emission in the Apartment Housing During the Maintenance period)

  • 이강희;채창우
    • KIEAE Journal
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    • 제8권4호
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    • pp.19-27
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    • 2008
  • The carbon dioxide is brought from the energy consumption and regarded as a criteria material to estimate the Global Warming Potential. Building shares about 30% in national energy consumption and affects to environment as much as the energy consumption. But there is not enough data to forecast the amount of the carbon dioxide during the maintenance stage. Various factors are related with the energy consumption and carbon dioxide emission such as the physical area, the building exterior area, the maintenance type and location. Among these factors, the building carbon-dioxide emission can be estimated by the overall building characteristics such as the maintenance area, the number of household, the heating type, etc., The physical amount such as the thickness of the insulation and window infiltration could explained the limited scope and might not be use to estimate the total carbon-dioxide emission energy because the each value could not include or represent the overall building. In this paper, it provided the estimation model of the carbon-dioxide emission, explained by the overall building characteristics. These factors are shown as the maintenance area, no. of household, the heating type, the volume of the building, the ratio of the window to wall area etc., For providing the estimation model of th carbon-dioxide emission, it conducted the corelation analysis to filter the variables and suggested the estimation model with the power model and multiple regression model. Most of the model have a good statistics and fitted in the curve line.

마이카 고전압 커패시터의 환경시험과 가속 수명시험을 통한 신뢰성 평가 (Reliability assessment of mica high voltage capacitor through environmental test and accelerated life test)

  • 박성환;함영재;김정석;김경훈;소성민;전민석
    • 한국결정성장학회지
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    • 제29권6호
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    • pp.270-275
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    • 2019
  • 마이카 커패시터는 세라믹 커패시터에 비해 내고충격 특성이 우수하여 다양한 유도무기체계의 고전압 기폭장치에 적용된다. 본 연구에서는 국산화된 마이카 고전압 커패시터의 고전압 기폭장치 적용을 위해 단자강도시험, 내습성시험, 열충격시험과 같은 환경시험과 함께 가속 수명 시험을 진행하였다. 마이카 고전압 커패시터의 고장모드는 절연저항 감소 및 이를 통한 절연 파괴이다. 가속수명모델의 중요 상수를 실험적으로 도출하였으며 전압계수 n 및 활성화 에너지 Ea는 각각 5.28 및 0.805 eV이었다. 가속모델식을 이용하여 도출한 가속계수는 496이었으며 가속수명시험을 통해 도출된 정상 사용 조건에서의 마이카 고전압 커패시터의 수명은 38.5년으로 기폭장치 적용에 문제가 없는 것으로 확인되었다.

너클 형상에 따른 LNG 저장탱크 코너프로텍션 피로수명 예측 (Prediction of Fatigue Life for a 270,000 kl LNG Storage Tank According to Shape of Corner-protection Knuckle)

  • 이승림;이경민;김한상
    • 한국가스학회지
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    • 제18권2호
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    • pp.69-72
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    • 2014
  • LNG 저장탱크의 9% Ni강 내부탱크가 파손되면 LNG가 유출되어 콘크리트 외부탱크가 LNG를 저장하게 되는데 이때 외부탱크의 내면과 외면의 온도차에 의해서 외부탱크 원통형 하단부에 큰 인장응력이 발생하게 된다. 이러한 온도차에 의해 발생되는 인장응력을 감소시키기 위해 단열재와 9% Ni 강재로 이루어진 코너프로텍션이 2차 방벽으로 설치된다. 본 눈문에서는 유한요소법을 이용하여 코너프로텍션의 직사각형 너클형상과 원형 너클형상에 따른 구조해석을 실시하여 Von-Mises 응력과 용접부의 피로수명을 예측하였다. 구조해석 결과 안전계수는 원형 너클이 직사각형 너클보다 23% 크게 나타났고, 피로수명은 원형 너클이 직각 너클보다 21% 크게 나타났다. 동 결과를 이용해서 향후 코너프로텍션의 수명평가 및 최적설계 등에 활용이 가능할 것이다.

친환경 섬유소재에 대한 대학생들의 인식도 연구 (University Students' Awareness of Eco-friendly Textile Fiber)

  • 이선영;이승구;김정화;이정순
    • 한국생활과학회지
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    • 제21권4호
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    • pp.781-790
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    • 2012
  • In midst of growing interest and awareness towards sustainability and being "green", there has been increased demand for sustainable clothing. In the purpose of boosting eco-friendly textiles industry, this research was conducted by investigating environmentally-conscious clothing behavior of university students and assessing their views on eco-friendliness of fibers. Thus, their awareness on recycled polyester fiber was evaluated. The research was conducted by surveying 257 university students residing in Daejeon. The data were analyzed with descriptive statistics, factor analysis, and reliability analysis, using SPSS 19.0. The results were as follows. 1) The majority of the subjects answered "Disposing clothing in the clothing recycling container" to reduce environmental impact. 2) Six factors of eco-friendliness of fiber were extracted as reutilization, unfinishedness, economics, environment preservation, natural materials, and slow fashion by using factor analysis. 3) Subjects scored organic cotton as most eco-friendly among various fibers. Recycled polyester fiber was graded less sustainable than natural fiber, but more eco-friendly than artificial one. 4) In assessment of subject's awareness of recycled polyester fiber, they highly valued on resource-reutilization and economics, but less valued on its hygiene, thermal insulation and health-functionality.

Assessment of Cryogenic Material Properties of R-PUF Used in the CCS of an LNG Carrier

  • Song, Ha-Cheol
    • 한국해양공학회지
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    • 제36권4호
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    • pp.217-231
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    • 2022
  • Reinforced polyurethane foam (R-PUF), a material for liquefied natural gas cargo containment systems, is expected to have different mechanical properties depending on its stacking position of foaming as the glass fiber reinforcement of R-PUF sinks inside R-PUF under the influence of gravity. In addition, since R-PUF is not a homogeneous material, it is also expected that the coordinate direction within this material has a great correlation with the mechanical properties. So, this study was conducted to confirm this correlation with the one between the mechanical properties and the stacking position. In particular, in this study, R-PUF of 3 different densities (130, 170, and 210 kg/m3) was used, and tensile, compression, and shear tests of this material were performed under 5 temperatures. As a result of the tests, it was confirmed that the strength and modulus of elasticity of the material increased as the temperature decreased. Specifically, the strength and modulus of elasticity in the Z direction, which was the lamination direction, tended to be lower than those in the other directions. Finally, the strength and elastic modulus of different specimens of the material found at the bottom of their lamination compared to the specimens with these properties found at positions other than their lamination bottom were evaluated. Further analysis confirmed that as the temperature decreased, hardening of R-PUF occurred, indicating that the strength and modulus of elasticity increased. On the other hand, as the density of R-PUF increased, a sharp increase in strength and elastic modulus of R-PUF was observed.

Accelerated Thermal Aging Test for Predicting Lifespan of Urethane-Based Elastomer Potting Compound

  • Min-Jun Gim;Jae-Hyeon Lee;Seok-Hu Bae;Jung-Hwan Yoon;Ju-Ho Yun
    • Elastomers and Composites
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    • 제59권2호
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    • pp.73-81
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    • 2024
  • In the field of electronic components, the potting material, which is a part of the electronic circuit package, plays a significant role in protecting circuits from the external environment and reducing signal interference among electronic devices during operation. This significantly affects the reliability of the components. Therefore, the accurate prediction and assessment of the lifespan of a material are of paramount importance in the electronics industry. We conducted an accelerated thermal aging evaluation using the Arrhenius technique on elastic potting material developed in-house, focusing on its insulation, waterproofing, and contraction properties. Through a comprehensive analysis of these properties and their interrelations, we confirmed the primary factors influencing molding material failure, as increased hardness is related to aggregation, adhesion, and post-hardening or thermal-aging-induced contraction. Furthermore, when plotting failure times against temperature, we observed that the hardness, adhesive strength, and water absorption rate were the predominant factors up to 120 ℃. Beyond this temperature, the tensile properties were the primary contributing factors. In contrast, the dielectric constant and loss tangent, which are vital for reducing signal interference in electric devices, exhibited positive changes(decreases) with aging and could be excluded as failure factors. Our findings establish valuable correlations between physical properties and techniques for the accurate prediction of failure time, with broad implications for future product lifespans. This study is particularly advantageous for advancing elastic potting materials to satisfy the stringent requirements of reliable environments.

단독주택 건물 그린리모델링에 따른 건물 에너지 성능과 운전비용 절감 효과 평가 (Energy Performance and Operating Cost Assessment for Implementing Green Remodeling Technologies in a Detached House)

  • 손병후;이수인;강재식
    • 한국지열·수열에너지학회논문집
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    • 제19권4호
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    • pp.27-38
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    • 2023
  • The Government the Republic of Korea is showing a lot of interest in net zero-energy buildings (NZEBs) to reduce energy consumption of buildings and to promote green growth policy in construction sector. The application of building passive technologies and renewable energies is essential to achieving NZEBs. Green remodeling reinforced the insulation of the exterior walls and roofs of the buildings and replaced high-efficiency windows and doors. In this study, the energy performance before and after green remodeling applied in a detached house was comparatively analyzed for baseline scenario and three different ones, ALT 1, ALT 2 and ALT 3. A building modeling and simulation software (DesignBuilder V7.0) with EnergyPlus (V9.4) calculation engine was used to calculate the energy demand and energy consumption for each scenario. Based on the calculation results of the building's energy demand for baseline, it was determined that the target building required more heating energy than cooling energy. The simulation results also showed that the implementation of building envelope performance improvement technologies (ALT 1) could notably decrease the heating energy consumption of the building. After the remodeling (ALT 1), the source energy consumption per unit floor area was assessed to be reduced by 65.2%, compared to prior remodeling of 338.7 kWh/m2 -y. Meanwhile, ALT 2 can achieve energy savings of 67.7% and ALT 3 can achieve savings of 73.1%. Following completion of the remodeling project, actual construction costs, and on-site measurements and verification results will be gathered and compared with the simulation results. Additionally, economic analysis including construction costs and payback period will be conducted using actual site data.

알카리활성 기포콘크리트의 품질특성 및 환경영향 평가 (Quality Characteristics and Environmental Impact Assessment of Alkali-Activated Foamed Concrete)

  • 양근혁;유성원;이현호;김상철
    • 한국건설순환자원학회논문집
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    • 제1권2호
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    • pp.114-119
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    • 2013
  • 본 연구에서는 공동주택의 난방시스템을 위한 단열재로서 지속가능한 알카리활성 기포콘크리트 배합설계를 제시하기 위한 5배합을 실험하였다. 알카리활성 결합재를 위해 73.5%의 고로슬래그와 15%의 고로슬래그가 5%의 수산화칼슘과 6.5%의 규산나트륨에 의해 활성화되었다. 주요 실험변수인 단위 결합재양은 $325kg/m^3$에서 $425kg/m^3$까지 $25kg/m^3$ 단위로 증가하였다. 실험결과 AA 기포콘크리트는 단위 결합재양이 $375kg/m^3$일 때 KS F 4039에서 제시하는 최소 강도조건 및 경제성을 만족시켰다. 또한 보통포틀랜드시멘트 기포콘크리트 대비 알카리활성 기포콘크리트의 환경영향 저감율은 광화학산화물의 경우 99%, 지구온난화의 경우 87~89%, 자원고갈의 경우 78~82%, 그리고 산성화와 인간독성의 경우 70~75% 수준으로서 매우 높았다.

설비공학 분야의 최근 연구 동향 : 2013년 학회지 논문에 대한 종합적 고찰 (Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2013)

  • 이대영;김사량;김현정;김동선;박준석;임병찬
    • 설비공학논문집
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    • 제26권12호
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    • pp.605-619
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    • 2014
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.