• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 제17회 워크샵 및 추계학술대회
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• pp.591-594
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• 2005

Geothermal energy becomes to be one of the promising energy sources. In this study, technology using water thermal energy from riverbank filtration system(including alluvial and riverbed deposit) is reviewed and checked as an energy resources. The objects of this study are (1) long-term monitoring of alluvial and riverbed sites, (2) preliminary design of cooling and heating system at riverbank filtration facility, and (3) calculation of potential groundwater heat energy, including riverbank filtration system. Measuring data of alluvial and riverbank filtration show slight fluctuations comparing to temperature of atmospheric air which indicates that groundwater obtained from the riverbank filtration system have a sufficient potential as a source of cooling and heating energy.

• 항공우주시스템공학회지
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• 제7권3호
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• pp.7-14
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• 2013

Hypersonic vehicles over Mach 5 need active cooling or thermal management systems to resolve excessive heating problems on their fuselage and engines. Endothermic fuels are widely used these days not only for the energy source but also for a heat sink. Therefore, fuel supply systems of hypersonic vehicles should be mainly composed of adiabatic fuel storage tank, cooling systems for the airframe and engine/nozzle, and fuel supply/injection systems in high pressure, high temperature, and high fuel flow rate conditions. This paper describes a conceptual design process of a hypersonic fuel supply system in order for designing a layout of the system, and identifying components and their specification requirements.

• International Journal of Air-Conditioning and Refrigeration
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• 제9권1호
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• pp.58-64
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• 2001

This study is to examine the emission quantity of $CO_2$ gas as the environmental load in office buildings. After the investigation of monthly consumption of each energy source(electricity and natural gas), it is analyzed that the $CO_2$ emission quantity of 34 office buildings surveyed is 22.4 kg-c/$m^2$-year, which consists of 17.5 kg-c/$m^2$-year by consurunlelectncif. and 4.9 kg-c/$m^2$-year by consuming natural gas. And the $CO_2$ emission quantity of each load in those buildings consists of 68% emitted by general electricity, 16% by cooling load and 16% by beating load. It is also proposed that the $CO_2$ emission quantity of cooling and heating load is profoundly pertinent to the variation of outdoor temperature.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 춘계학술발표대회 논문집
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• pp.13-18
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• 2009

Building is a major energy consumer, and now many efforts are made to save energy in the design and using equipments. The most noticeable achievement in those efforts is a building energy performance assessment program. But most programs are not satisfying enough to provide exact meteorological data, and data source and calculation, and data collection period are not clearly defined. That is common in most of domestic programs. This study collects typical meteorological data in 16 items and analyzes them with Visual DOE 4.0 to compare with existing data. The comparison found that revised data shows a 11% increase on average during cooling period from June to September, and a 13% decrease on average during heating period from December to February, in terms of building heating and cooling load in a monthly basis.

• 천문학논총
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• 제7권1호
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• pp.63-69
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• 1992

We have systematically investigated the X-ray spectra of normal galaxies, by using the Imaging Proportional Counter (IPC) data in the Einstein data base. We employed the X-ray color-color plot as well as the standard model fitting method which requires higher signal to noise ratio. We discuss X-ray emission mechanisms in terms of their spectral properties and the signature of cooling flows which are most likely present in X-ray bright early type galaxies. On the average, fits to absorbed thermal spectra show that the X-ray emission temperature of spirals is higher than that of ellipticals. This is consistent with our understanding that accreting binaries are a major X-ray source in spirals, while extended gaseous halos are present in ellipticals. The emission temperature becomes lower with increasing X-ray to optical luminosity ratio in E and S0 galaxies. This result is what we would expect if the emission of X-ray faint early type galaxies consists of a large evolved stellar component, while the gaseous emission becomes dominant in X-ray brighter galaxies. We also find a cool, self-absorbed core in some early type galaxies, which directly indicates the presence of cooling flows in such galaxies.

• 한국전산유체공학회지
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• 제18권2호
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• pp.9-16
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• 2013

The heat transfer enhancement of heat sink with mist flow is studied numerically by solving the conservation equations for mass, momentum and energy in the continuous and dispersed phases. A Lagrangian method is used for tracing dispersed water droplets in the heat sink and an Eulerian species transport model for air and steam mixture. The continuous and dispersed phases are interacted with the drag and evaporation source terms. The computed results show that addition of evaporating mist droplets enhances the cooling performance of heat sink significantly.

• 한국소음진동공학회논문집
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• 제21권6호
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• pp.529-535
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• 2011

Indoor noise is very important related to the morale and fighting power of the crew as well as environmental condition for them in a navel vessel. Especially, the crew members working in CIC (combat information center) and sonar equipment room require much more quiet environment condition. One of the most serious noise source in CIC is the cooling fan noise installed in the console of the combat system. Therefore, in this paper, the design of the plenum chamber is studied to reduce the noise of the fan from these consoles by numerical analysis and experiment.

• 천문학회보
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• 제35권1호
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• pp.71.2-71.2
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• 2010

Cooling hot gas sets a floor on the ionization level for diffuse gas in the ISM in general and the galactic halo. Many high galactic latitude sight lines, cooling hot gas is the dominant source of the ionization. Such sites are prime regions for the formation of both C IV and Si IV ions at a temperature of T~105K. To study of the ISM that have the 104.5~6K ionization state by ionization or photoionization by the collision, searching for the radiation energy that is emitted at far ultra violet range is required. In this paper, we report the analysis of NGP( North Galactic Pole, $l:270^{\circ},b:90^{\circ},rad:40^{\circ}$) region by fuv($1350{\sim}1750{\AA}$) data that are surveyed with FIMS. After making the FIMS FUV image of the NGP region, we divided up into 50 small regions for that and got the spectrum emission lines from each one.

• 천문학회보
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• 제35권2호
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• pp.70.2-70.2
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• 2010

Cooling hot gas sets a floor on the ionization level for diffuse gas in the ISM in general and the galactic halo. Many high galactic latitude sight lines, cooling hot gas is the dominant source of the ionization. Such sites are prime regions for the formation of both C IV and Si IV ions at a temperature of T~105K. To study of the ISM that have the 104.5~6K ionization state by ionization or photoionization by the collision, searching for the radiation energy that is emitted at far ultra violet range is required. In this paper, we report the analysis of NGP(North Galactic Pole, $l:0^{\circ},b:90^{\circ}$,rad: $40^{\circ}$) region by fuv($1350\sim1750\AA$) data that are surveyed with FIMS. After making the FIMS FUV image of the NGP region, we divided up into some small regions for that and got the spectrum emission lines from each one.

• 전력전자학회논문지
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• 제9권4호
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• pp.350-355
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• 2004

본 논문에서는 열원인 전력용 반도체 소자와 방열판 및 팬으로 구성된 강제 냉각방식 방열 시스템을 먼저 해석 가능한 요소로 나눈 후 각 요소에 대한 해석적이거나 실험적인 설계 식을 제시하고 이를 적용한 설계 방법을 제안하였다. 제안한 방법으로 400kW급 IGBT 인버터용 강제 냉각방식 방열 시스템을 설계하고 제작하였다. 실험결과는 설계 온도가 실험치에 대해 10［%］ 오차 범위 내에서 잘 일치함을 검증하여 제안한 해석적인 정상상태 설계방법의 타당성을 보였다.