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상온에서 $1100^{\circ}C$까지 온도변화에 따른 콘크리트의 열물성 측정치
신기열,정모,김상백,김종철,Shin, Ki-Yeol,Chung, Mo,Kim, Sang-Baik,Kim, Jong-Chul 대한기계학회 1998 大韓機械學會論文集B Vol.22 No.5
Thermophysical properties and the compressive strength of concrete used in nuclear power plants in Korea were measured. The chemical composition of the concrete was also analyzed. The measured thermophysical properties include the density, the thermal conductivity, the thermal diffusivity and the specific heat for a wide temperature range of 20.deg. C to 1100.deg. C. The chemical composition of Korean concrete is similar to that of US basaltic concrete and the thermophysical properties are strongly temperature dependent. The density, the conductivity and the diffusivity decrease with an increase in temperature, and particularly the conductivity and the diffusivity are a 50-perdent decrease at 900.deg. C as compared with these values at room temperature. The specific heat increases until 500.deg. C, decreases from 700.deg. C to 900 .deg. C, and then increases again when temperature is above 900.deg. C. The measurement beyond 1100.deg. C is not acceptably accurate because the concrete decomposes to a liquid phase from a solid phase at that temperature. The results of this study can be applied, for example, to an analysis of the molten core-concrete interaction (MCCI) phenomenon of concrete structures at high temperature will also require those property data, especially for high temperature ranges.
플라즈마 용사에 있어 플라즈마 가스와 분말입자의 열전달 상호작용에 대한 수치해석
신기열(Ki-Yeol Shin),정모(Mo Chung) 한국전산유체공학회 1997 한국전산유체공학회 학술대회논문집 Vol.1997 No.-
Numerical analysis of the jet flow which was developed from DC non-transfered plasma torch was investigated for an analysis of thermal palsma spray characteristics. The numerical flow field resulted in a two-dimensional, steady state fluid model where the turbulence effects were considered in the standard K-ε model. The sprayed particle-plasma interaction with dual injection ports are considered.
차경엽(Kyung-Yup Cha),신기열(Ki-Yeol Shin) 한국에너지기후변화학회 2021 에너지기후변화학회지 Vol.16 No.1
Energy demand management is a way to achieve energy conservation by improving the energy use efficiency of consumers or by changing energy consumption behavior. In spite of the governments mid-to-long-term plan and various financial support and regulatory policies, Koreas energy consumption is steadily increasing and efficiency improvement is insufficient. In this study, energy efficiency was assessed by quantitative analysis methods in the industrial sector, which accounts for a large portion of energy consumption, in order to analyze the operation status of energy demand management in Korea. From the study, it was found that despite the governments efforts, the energy efficiency of the industrial sector has not improved. This was due to the increase in consumption by more energy intensity companies with an annual energy consumption of 2,000 TOE or more, and some high-energy intensity industries such as steel and petrochemicals. And the result of factor analysis shows that the improvement effect of energy intensity in more energy efficiency industries is insufficient. Besides, by company size, small and medium-sized enterprises are showing improvement in energy efficiency, but it was found that large-sized enterprises are not effective.
LED 히트싱크 설치조건과 형상변화에 따른 방열성능 실험
정연국(Yeon-Guk Jeong),신기열(Ki-Yeol Shin),김준환(Jun-Hwan Kim) 대한기계학회 2020 대한기계학회 춘추학술대회 Vol.2020 No.12
In this paper, an experiment was conducted to investigate the heat dissipation performance by changing installation angles and the design shape of a heat sink in the automotive LED(Light Emitting Diode) lamps. The surface convective heat transfer coefficient can be derived through the heat dissipation performance test according to the installation angles as vertical and horizontal directions. The general thermal performance test of heat sink was performed at the natural convection experimental conditions. As a result, the heat sink installation angle of 90° by the horizontal direction showed the best heat dissipation performance, and when convective holes are added, the junction temperatures were measured lower than normal shape as 2.4~2.8℃ less because of the fin surface heat transfer improvement. However, as conductive heat resistance in the basement increases by the number of holes, the optimal design condition of the convective hole was existed for improving the total heat dissipation performance.
진태환(Tae-Hwan Jin),신기열(Ki-Yeol Shin),임용훈(Yong-Hoon Im),윤시원(Si-Won Yoon),장기창(Ki-Chang Chang) 대한기계학회 2016 대한기계학회 춘추학술대회 Vol.2016 No.12
A high energy, efficient, harmonious, ecological greenhouse has been highlighted by advanced future agricultural technology recently. This greenhouse is essential for expanding the production cycle toward growth conditions through combined thermal environmental control. However, it has a negative effect on farming income via huge energy supply expenses. Because not only production income, but operating costs related to thermal load for thermal environment control is important in farming income, it needs studies such as a harmonious ecological greenhouse using natural ventilation control. This study is simulated for energy consumption and thermal environmental conditions in a three-layered greenhouse by natural ventilation using window opening. A virtual 3D model of a three-layered greenhouse was designed based on the real one in the Gangneung area. This 3D model was used to calculate a thermal environment state such as indoor temperature, relative humidity, and thermal load in the case of a window opening rate from 0 to 100 %. There was also a heat exchange operated for heating or cooling controlled by various setting temperatures. The results show that the cooling load can be reduced by natural ventilation control in the summer season, and the heat exchange capacity for heating can also be simulated for growth conditions in the winter season.
진태환(Tae-Hwan Jin),유걸(Jie Liu),정모(Mo Chung),신기열(Ki-Yeol Shin) 대한기계학회 2020 大韓機械學會論文集B Vol.44 No.12
본 연구에서는 당진시 스마트팜 단지 조성을 위한 열에너지 공급안을 분석하였다. 먼저 TRNSYS 프로그램으로 시계열 날씨 정보와 3D 벤로형 유리온실 모델을 통해 동적 에너지부하를 산정하였다. 그리고 경유보일러, 발전온배수, 하천수, 외기열 활용 열펌프를 동적 에너지부하를 통해 적정용량으로 난방설비 모델로 구성하였고, 저온성 및 고온성 작물의 생육조건에 맞는 난방운전 모델을 구성하였다. 이를 통해 case별 난방성능 평가와 경제성 평가를 위한 case study를 수행하였다. 그 결과, 해당 지역에서는 저온성 작물이 고온성 작물에 비해 400% 가량 더 우수한 경제성을 가지며, 고온성 작물에는 50% 이상의 금융 보조금이 필요한 것으로 평가되었다. 또 열펌프를 사용한 경우 보일러에 비해 운영비를 40% 가량 감소시킬 수 있어 보다 우수한 경제성을 가지는 것으로 분석되었다. In this paper, the thermal energy supply plan for a smart farm complex in Dangjin area was analyzed. First, the dynamic energy load was calculated by time-series weather data and 3D venlo-type glass greenhouse model with the TRNSYS program. In addition, the boiler and power plant waste water source heat-pump, stream water source heat-pump, and the ambient air source heat-pump was configured as the heating facility model with optimum capacity through dynamic energy load value. The heating simulation to maintain growth conditions of crops familiar with low-temperature and high-temperature was also performed. Through these models, the heating performance and economic evaluation in each cases were carried out. As a result, it was evaluated that low-temperature crops (strawberry) has a better economic performance by 400 % than high-temperature one (tomato), and 50 % or more of government subsidies should be required for high-temperature crops. It was analyzed that the heat pump heating cases showed better economic efficiency because the operating cost could be reduced by about 40 % compared to the boiler.