• 한국지반공학회논문집
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• 제37권1호
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• pp.5-15
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• 2021

북극권과 같은 한대지역의 동상민감성 지반은 계절적 대기 온도 변화 및 설치된 구조물의 온도에 의해 지반의 융기 및 침하 문제가 존재한다. 이러한 동상민감성 지반의 융기 및 침하 방지를 위한 지반안정화 공법으로는 매립 및 치환공법, 열 사이펀 등이 존재한다. 여기서 열 사이펀이란 내부 냉매의 증발, 응축을 반복하며 열 순환을 통해 이상 유동(two-phase flow)의 형태로 냉매가 지반의 온도를 외부로 전달하여 지반 온도를 조절 할 수 있는 공법이다. 본 연구는 이러한 열 사이펀의 성능을 열전도율로 수치화하기 위하여 ABAQUS 내부의 User-subroutine 코딩을 통해 열 사이펀을 지중의 한 열원으로 간주, 경계조건으로 적용시켜 기존 문헌의 열 사이펀 실내모형실험의 온도분포 결과와 비교하여 산정하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.553-554
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• 2009

광섬유센서 등과 같은 정밀온도센서를 이용하여 기온, 수온 및 수중 지표면 온도를 측정하고, 각각의 온도 변화에 대응하여 교량 세굴 및 수위를 파악할 수 있는 계측시스템을 개발하고 이를 소개한다. 온도계측을 통한 교량 세굴 및 수위 측정 방법은, 온도를 측정할 수 있는 센서를 수중 지표면을 기준으로 일정깊이와 높이로 설치하여 각각의 위치에 따른 온도 변화량을 분석하여 세굴량을 추정하는 시스템이며, 센서를 교각 상부까지 연장할 경우 수심 측정까지도 가능한 방법이다.

• 한국화재소방학회논문지
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• 제24권6호
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• pp.1-6
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• 2010

산불 형태 중에서 뒷불은 지표층 내부의 발화점 이상 온도가 분해층에서 부식층으로 전이되어 뒷불이 발생 할 수 있는 형태로 잠재적 위험성을 가지고 있다. 본 논문은 뒷불의 현장과 유사한 지표층 구조로 설정하여 실험을 통해 뒷불의 잠재적 위험성과 연소특성 규명을 목적으로 한다. 시료는 침엽수종 소나무 낙엽층과 활엽수종 굴참나무 낙엽층으로, 실제 산림내의 지표층 구조인 낙엽층, 분해층, 부식층로 구분하여 재현하였다. 8개의 열전대(K-type)를 층별 경계면과 그 사이에 배치하여 전이온도, 지속시간, 전파속도를 측정하였다. 결과적으로 F-H층으로 전이되는 경우와 전이가 일어나지 않은 경우는 L층과 F층 경계면의 발화조건이며, 유기물층의 뒷불 전이 임계습도는 35~44% 사이에 존재하며, 온도는 $350^{\circ}C$ 이상시 뒷불 전이가 일어날 확률이 아주 높다는 결론을 도출하였다. 본 연구에서는 다층구조의 뒷불 모델을 제시하였으며 이를 사용하여 훈소의 층간 전이현상, 함수율에 따른 발화여부, 전파속도 및 시간에 따른 경계면의 온도변화 등을 알 수 있었다. 또한 뒷불의 연소특성을 규명할 수 있는 실험방법을 확립하였다.

• 신재생에너지
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• 제3권4호
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• pp.47-53
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• 2007

Effluent ground water overflow in deep and broad ground space building. Temperature of effluent ground water is in $12{\sim}20^{\circ}C$ annually and the quality of that water is as good as living water. Therefore if the flow rate of effluent ground water is sufficient as source of heat pump, that is good heat source and heat sink of heat pump. Effluent ground water contain the thermal energy of surrounding ground. So this is a new application of ground source heat pump. In this study open type and close type heat pump system using effluent ground water was installed and tested for a church building with large and deep ground space. The effluent flow rate of this building is $800{\sim}1000ton/day$. The heat pump capacity is 5RT each. The heat pump cooling COP is $4.9{\sim}5.2$ for the open type and $4.9{\sim}5.7$ for close type system. The system cooling COP is $3.2{\sim}4.5$ for open type and $3.8{\sim}4.2$ for close type system. This performance is up to that of BHE type ground source heat pump.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.471-476
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• 2007

Effluent ground water overflow in deep and broad ground space building. Temperature of effluent ground water is in $12{\sim}20^{\circ}C$ annually and the quality of that water is as good as living water. Therefore if the flow rate of effluent ground water is sufficient as source of heat pump, that is good heat source and heat sink of heat pump. Effuent ground water contain the thermal energy of surrounding ground. So this is a new application of ground source heat pump. In this study open type and c lose type heat pump system using effluent ground water was installed and tested for it church building with large and deep ground space. The effluent flow rate of this building is $800{\sim}1000$ ton/day. The heat pump capacity is 5RT each. The heat pump cooling COP is $4.9{\sim}5.2$ for the open type and $4.9{\sim}5.7$ for close type system. The system cooling COP is $3.2{\sim}4.5$ for open type and $3.8{\sim}4.2$for close type system. This performance is up to that of BHE type ground source heat pump.

• 신재생에너지
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• 제3권2호
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• pp.40-46
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• 2007

Effluent ground water overflow in deep and broad ground space building. Temperature of effluent ground water is in $12{\sim}20^{\circ}...$ annually and the quality of that water is as good as well water. Therefore if the flow rate of effluent ground water is sufficient as source of heat pump, that is good heat source and heat sink of heat pump. Effuent ground water contain the thermal energy of surrounding ground. So this is a new application of ground source heat pump. In this study open type and close type heat pump system using effluent ground water was installed and tested for a church building with large and deep ground space. The effluent flow rate of this building is $800{\sim}1000\;ton/day$. The heat pump capacity is 5RT. The heat pump heating COP was $3.85{\sim}4.68$ for the open type and $3.82{\sim}4.69$ for the close type system. The system heating COP including pump power is $3.0{\sim}3.32$ for the open type and $3.32{\sim}3.84$ for close type system. This performance is up to that of BHE type ground source heat pump.

• KIEAE Journal
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• 제14권3호
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• pp.65-70
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• 2014

The thermal environment in a small city rapidly deteriorates due to the urbanization and overpopulation. It is important to understand and predict the thermal environment in a city area. The thermal environment is highly affected by the solar radiation and temperature distributions changing over time periodically. To predict the thermal environment precisely, the solar radiation calculation including radiation strength, incidence angle, and thermal radiation between building surface and ground should be considered. In this study, the computational domain includes various artificial structures such as building, ground, asphalt, brick and grass. To consider the solar radiation, the unsteady state numerical calculation is performed from sun rise to mid-day (2:00pm). The numerical methods consist of solar load and one dimensional heat conduction through the boundaries to reduce the computational load and improve the flexibility of the calculation.

• 한국주거학회논문집
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• 제22권3호
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• pp.25-33
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• 2011

Recently, concerns about conserving proper size of urban green spaces and accessibility are increasing, regarding it as a solution to diverse urban environmental problems including pollution, ecosystem deterioration, urban climate change. Artificial ground greening such as green roofs is regarded as the only alternative that can conserve green spaces which are impossible to be secured on the ground. However, green roofs are not popularized yet and levels are very low in provincial cities despite of related technology development and support systems of related agencies. Based on the background, this study tries to present a theoretical basis of methods for green roofs, conducting green roof simulations Finally, it aims to offer base data which help establish policy direction for activation of green roof technology. As a result of a simulation for verifying temperature reduction effect, it was possible to affirm effect of a plot that green roofs applied. Especially, it was revealed that a green roof method using ground covers such as mixed planting was the most effective way to reduce temperature. Based on precise analysis of the users, actual study for activation of green roofs should be developed in the future, by presenting a standard model for experiments and obtaining information about examples of green roofs on private houses.

• 한국환경과학회지
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• 제24권3호
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• pp.281-290
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• 2015

Recent climate change has led to fluctuations in agricultural production, and as a result national food supply has become an important strategic factor in economic policy. As such, in this study, panel data was collected to analyze the effects of seven meteorological elements on the production of five types of grain with error component panel data regression method following the test results of LM tests, Hausman test. The key factors affecting the production of rice were average temperature, average relative humidity and average ground surface temperature. The fluctuations in the other four grains types are not well explained by meterological elements. For other grains and beans, only average temperature and time (year) affect the production of other grains while average temperature, ground surface temperature, and time (year) influence the production of beans. For barley and millet, only average temperature positively affects the production of barley while ground surface temperature and time (year) negatively influence the production of millet. The implications of this study are as follow. First, it was confirmed that the meteorological elements have profound effects on the rice production. Second, when compared to existing studies, this study was not limited to rice but encompassed all five types of grains and went beyond other studies that were limited to temperature and rainfall to include various meteorological elements.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 봄 학술발표회논문집
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• pp.111-118
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• 2000

Concrete cracking due to the temperature gradient across the wall, caused by the difference in temperature between cryogenic liquid natural gas stored and surrounding environment of in-ground LNG storage tank, is investigated in this study. Crack propagation of concrete LNG tank is effectively simulated by using a layered degenerated shell element. In addition, material nonlinearity is taken into consideration on the basis of the nonlinear elastic-orthotropic model. Finally, numerical analysis for a real LNG storage tank is conducted with the objective to verify the efficiency of the introduced model.