• 한국태양에너지학회 논문집
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• 제26권1호
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• pp.1-6
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• 2006

This paper presents the heating and cooling load estimations for the library of a cultural center building located in Gwangju Korea by TRNSYS with Type 56 of multi-zone building components. In this study, energy rate control mode is selected and the design temperatures for heating and cooling are specified respectively as 20oC and 26oC. Reading rooms of the library are located on the third floor of the cultural center building, and this third floor space is modeled as the five thermal zones for the TRNSYS simulation. Among the five zones, attention is given to the two zones which are the reading rooms 1 and 2. Since these two zones are to be heated and cooled by the solar thermal system which is planned to be installed in the building, dynamic thermal behaviors of the two zones are analyzed by the heating and cooling load estimations.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.953-958
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• 2006

Perimeter zone has been reinforced by active systems, such as fan-coil units, because it causes an increase in heating and cooling loads, dew condensation in winter, or discomfort with cold-draft to residents in buildings, through poor insulation by light-weighed skin due to progressing multi-storied buildings and skyscrapers. However, because these active systems raise Its capacity so that fossil fuel is used as much as they are added, and ultimately, greenhouse effect is urged, we proposed BIPV system functioned as solar collector which can substitute active system. As an early stage, heat balance equation in steady-state by Fortran was used not only for pre-heating effect and electric power capacity during the day in winter, but also for electric power capacity during day in slimmer and sky radiation effect during night in summer. Especially, we should have considered shading on PV, since even a little bit of it makes the efficiency too low for the PV to work. Still, when the flux of pre-heated air was increased to make air-barrier, its temperature was not enough to make it because the speed of heat exchange was too fast to warm up the air, thus the capacity to meet the condition was evaluated, and electric power from PV was made used for it.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.399-404
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• 2006

Heating and cooling load of ventilation is a very important part of building energy saving. Improving ventilation effectiveness can save building energy consume and supply fresh air to indoor efficiently. So this study measured mulity-zone aiflow and ventilation effectiveness according to ventilation types. Result of measurement show that ventilation effectiveness is depends on ventilation system design rather than ventilation types.

• 한국주조공학회지
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• 제17권6호
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• pp.598-607
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• 1997

Fractional melting process involves heating an alloy within its liquid-solid region simultaneously ejecting liquid from the solid-liquid mixture. The extent of the purification obtained is comparable to that obtained in multi-pass zone refining. The new fractional melting process in which centrifugal force was used for separating the liquid from the mixture has been developed and applied to the purification of the metallic grade. Refining ratio depends on partition ratio, cake wetness and diffusion in the solid, and it was controlled by various processing parameters such as rotating speed and heating rate. The new parameter called "refining partition coefficient" has been suggested to estimate the effects of processing variables on the refining ratio. Because major impurities in MG-silicon such as Fe, Al, Ni have a low segregation coefficient, good purification effect is expected. The results of refining MG-silicon(98%) showed that 3N-Si was obtained in refined solid of 50% of the original sample.

• 한국정밀공학회지
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• 제24권7호
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• pp.98-105
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• 2007

In modern industries, materials are required that possess multi-functional properties and at the same time flexibility in their shapes with structural stability. The major technology realizing this requirement consists of thinning metal wires and laying them with stable contact nodes. This research has dealt with a new method to manufacture thin wires by drawing without applying dies, but with introducing enforced necking, which enables to process multi-ends. Based on the new method, the process dynamics was modelled and its steady-state characteristics were analyzed. Results showed that the profiles of the material velocity in the drawing zone increased with a downward convex shape, while the cross-sectional area decreased with the shape of upward convex. The microwave heating turned out to be effective in wire drawing, but dependent on the input feeding direction. The variation in the diameters of the drawn wires was negatively affected by increasing the drawing ratio.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.304-309
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• 2008

The heating and cooling performances of system multi-air conditioner for various refrigerant flow rates with high-head and long-line conditions are experimentally investigated. The maximum head and tube length were 110 m and 1000 m, and the two different adjustments of refrigerant flow rates were +20 % and -20 %, respectively. The experimental system was composed of 4 outdoor units with module systems, and 13 indoor units which were joined with the mode change unit by single-tube circuit. Field tests without indoor and outdoor temperature control were performed in a general office building with two different refrigerant flow rates. Especially, the oil level in the compressor was normally maintained at the safety zone. Experimental results were prepared on the p-h diagram.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.760-765
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• 2000

The study deals with the development of a computational procedure for evaluating the temperature rise in dry and lubricated multi-layered contacts of head/disk interface. A transient computational model with a transformed rectangular computational domain is utilized. A model and a computational method for micro-contact with sub-lubricated zone, including friction heat generation, have been presented. The model was applied, taking full account of the changes in contact area and contact load due to frictional heating. The computational distribution of temperature is obtained with the analytical findings for various composition and contact conditions. Especially, a rapid rise ($220^{\circ}C$ or above) in read head temperature lese to a saturation in the influence of a thermal spike on signal performance. This general class of problems can be treated provided that heat generation distribution and layer properties are known.

• 대한기계학회논문집B
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• 제24권9호
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• pp.1195-1209
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• 2000

The purpose of this study is to develop the non-gravity fluidized dryer. In this non-gravity fluidized dryer the fluidized zone is produced by two paddles in mixer, which maximizes the surface area of materials and then heated air through the guiding panels dehumidify them. This can conduct the drying process quickly and control moisture contents to lower limits. The ventilation system is closed loop system, which can be changeable to open system, and can be used as a multi-purposed dryer in which mixing, drying, granulating and cooling process is conducted. In order to develop the non-gravity fluidized dryer, in the first fundamental experiments were performed to mixing accuracy and then the other parts of dryer and control system were examined to check whether they were designed properly and operated harmoniously with mixer. Also the preparatory experiments were fulfilled to examine the efficiency and reliability of the dryer. Lastly, on the basis of preparatory experiments, performance test for the non-gravity fluidized dryer carried out for the variation of the initial moisture contents, desired moisture contents, heated air velocity and heating temperature.

• 생물환경조절학회지
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• 제19권4호
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• pp.189-194
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• 2010

본 연구는 딸기의 수경재배에서 전열선이 삽입된 온수관을 이용하여 배지의 지하부 온도를 관리할 수 있는 가온시스템을 개발하고, 가온튜브내 물의 온도가 $25^{\circ}C$ 일 때 배지 4종류(왕겨, 펄라이트, 왕겨 80%+피트모스20%, 펄라이트80%+피트모스20%), 멀칭 2종류(멀칭무, 멀칭)의 처리구별로 온실기온 3수준(5, 10, $15^{\circ}C$)에 따른 배지 내 온도의 변화를 측정하였다. 그 결과로 다선식 기온튜브의 제어성능은 3선식이 설정온도 도달성이 30분이며 제어된 온도폭 ${\pm}1^{\circ}C$로서 가장 좋은 것으로 니타났다. 배지의 종류별로는 펄라이트 80%의 배지보다 왕겨 80%의 배지가, 멀칭 유무 별로는 멀칭한 경우에서 배지온도가 안정되는 시간이 180분으로 빠르게 나타났다. 왕겨 배지, 멀칭, 온실내 기온 $5^{\circ}C$ 일 경우 배지온 모델에서 온도상수 a는 -0.1458, b는 -0.1088로 나타났으며, 개발된 모델을 이용할 경우 저온기에서 온실내 기온에 따라 배지내 온도상승을 예측할 수 있다.

• 한국초전도ㆍ저온공학회논문지
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• 제9권1호
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• pp.18-21
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• 2007

Highly textured MgO template by ion-beam-assisted deposition(IBAD) was successfully fabricated using a continuous reel-to-reel(R2R) mode. To enlarge the deposition area, the previous IBAD system was modified into the system with 14-pass and five heating zone. Every processing step was carried out using this multi-turn IBAD system. The overall process consists of R2R electropolishing of a hastelloy C276 tape, deposition of $Al_2O_3$ diffusion barrier, $Y_2O_3$ seed layer, IBAD-MgO and homoepi-MgO layer. The IBAD-MgO templates were fabricated using the IBAD system with 216 cm-length deposition zone and 32 cm diameter ion source. The texture of MgO films developed during the IBAD process was monitored by in-situ reflection high energy electron diffraction(RHEED) to optimize the IBAD process. Recently, 100 m long IBAD-MgO tape with in-plane texture of $\Delta{\phi}<10^{\circ}$ was successfully fabricated using the modified IBAD system. In this report, the detailed deposition condition of getting a long length IBAD-MgO template with a good epitaxy is described.