• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.20 no.3
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• pp.175-183
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• 2010

Windows are widely used for natural ventilation of the various buildings. Especially high level windows as a part of industrial ventilation systems, play a crucial role in natural ventilation. Compared to mechanical ventilation system, natural ventilation has the advantage of lower installation and operating costs. In general, high level windows for industrial buildings have three types; louver type, 45$^{\circ}$ open type and 90$^{\circ}$ open type. Based on previous studies, it was found that the louver type and 45$^{\circ}$ open type are very effective in reducing rainwater penetration, but they did not have enough ventilation efficiencies. Preliminary tests were performed with the various types of windows. It was found that a 90$^{\circ}$ open double layer type window was the best among those which tested in our preliminary tests. Simulated rain was used to estimate the amount of rain penetrated through windows and to observe the paths of rain penetration. Various 90$^{\circ}$ open windows were tested to find the windows with minimum rain penetration and maximum ventilation efficiency.

• Journal of Environmental Science International
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• v.20 no.5
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• pp.581-587
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• 2011

Industrial natural ventilation systems consist of gravity ventilator, the high/low windows and doors. Especially, the high windows play an important role in the industrial natural ventilation systems. Generally speaking, industrial high windows are divided into 3 types; louver type, $45^{\circ}$ open type and $90^{\circ}$ open type. This study was numerically and experimentally conducted. Three types of windows were tested to know the ventilation characteristics and estimate the ventilation efficiencies. Numerically, computational fluid dynamics software (AIR PAK Ver. 2.0) was used to observe the flow characteristics inside the industrial building and the concentration contours generated by the tracer gas method. Experimentally, the flow visualization technique and the tracer gas method were applied with the model building to characterize the flow pattern inside the model building and to estimate the ventilation efficiencies with the different windows. It was found that $90^{\circ}$ open type window was most effective for the discharge of pollutants from the industrial building. On the other hand, the louver type window was found to be less effective than any other windows.

• JOURNAL OF ELECTRICAL WORLD
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• s.277
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• pp.63-68
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• 2000

요 몇 해 사이에 고내압$\cdot$대용량 파워디바이스에서는 아주 새로운 진전이 일어나고 있다. 파워일렉트로닉스 장치의 소형화$\cdot$고효율화 및 제어의 고속화 등의 요구에 응할 수 있는 차세대의 새로운 소자가 출현하여 그 제품화가 비약적으로 진전되고 있는 것이다. 새로운 파워디바이스의 대표적인 것으로는 다음의 3가지를 들 수 있다. $\cdot$HVIGBT(High Voltage Insulated Gate Bipolar Transistor Module)$\cdot$HVIPM(High Voltage Intelligent Power Module)$\cdot$GCT(Gate Commutated Turn-off)사이리스터 이들의 파워디바이스를 종래의 GTO(Gate Turn-off) 사이리스터와 비교해 보면 다음과 같은 특징이 있다.(1)GTO 사이리스터가 필요로 했던 스나버회로가 없어도(Snabber-less)턴오프가 가능하며, di/dt 억제용 아노드리액터의 생략 또는 저감이 가능하기 때문에 반도체 부녀회로의 소형화를 기할 수 있다. (2)게이트파워와 전체손실(소자 및 주변회로를 포함)의 저감으로 에너지 절약을 도모할 수 있다. (3)스위칭주파수를 2$\~$3kHz 정도까지 높일 수 있다. 이런 장점 때문에 다음과 같은 용도에의 적용이 기대되고 있다. (1)신간선, 지하철 등의 전철 응용 (2)액티브필터, SVG(무효전력발생장치), SVC(무효전력보상장치) BTB, 가변속 양수발전 스위치 등의 전력응용 (3) 철강압연이나 제지공장용 등의 대용량공업용 컨버터$\cdot$인버터 응용 HVIGBT와 HVIPM은 전철분야에서 신간선의 추진용 컨버터$\cdot$인버터장치와 보조전원장치, 그리고 지하철의 추진용 인버터 장치나 보조전원장치 등에 채용되고 GCT 사이리스터는 전력용 주파수변환기 등에 실용화되고 있다.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.705-706
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• 2008

When heat generated inside a large factory building is not discharged due to a stagnant flow, the working environment of workers becomes worse and the cooling of high-temperature products such as hot-rolling coils is delayed. To investigate the natural ventilation inside a large factory building, experimental studies were carried out using wind-tunnel tests. The scale-down factory building models were placed in an atmospheric boundary layer (ABL) and the mean and fluctuating velocity fields were measured using a particle image velocimetry (PIV) technique. For the prototype factory model, the outdoor air is only entrained into the factory building through the one-third open windward wall, and stagnant flow is formed in the rear part of the target area. In order to improve the indoor ventilation environment of the factory building, three different louver-type ventilators were attached at the upper one-third open windward wall of the factory model. Among the three louver ventilators tested in this study, the ventilator model #3 with the outer louver (${\theta}_o$ = 90$^{\circ}$) and the inner louver (${\theta}_i$ = -70$^{\circ}$) was found to improve the natural ventilation inside the factory building model effectively. The flow rate of the entrained air was increased with aligning the outer louver blades with the oncoming wind and guiding the entrained air down to the ground surface with elongated inner louver blades.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.1209-1211
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• 2017

창문을 열고 닫음에 있어서 사람의 신체에 따라, 창문의 위치에 따라 어려움이 발생한다. 또한 최근 대기 오염도가 심해지고 지구 온난화로 인한 한반도 기후 변화로 국지성 집중호우의 빈도가 증가하고 있다. 이로 인해 사용자가 부재중일 때 창이 열려있다면 집 안으로 먼지가 들어올 것이고, 국지성 호우에 의해 비가 들어오는 경우가 생길 수 있다. 본 논문에서는 이 문제점들에 주목하여, 어플과 연계를 통한 원격 창문 개폐 장치를 고안하였다. 본 장치를 이용한다면 신체적인 한계가 있는 어린이, 노약자, 장애인과 같은 이들이 쉽게 창문을 개폐할 수 있을 것이다. 그리고 환기가 필요한 공장, 격납고 등의 높은 위치에 있는 창문을 쉽게 개폐할 수 있어 분진 폭발로 인한 안전사고 역시 예방하는 효과가 있을 것이다. 또한 사용자가 외출할 때 창문을 닫고 나오지 못한 경우 어플을 이용하여 원격으로 닫을 수 있으며, 이를 통해 밖에 황사, 미세먼지가 들어오는 것과 비가 들어오는 것을 차단할 수 있다. 마지막으로 열린 창을 닫는다는 것에서 방범의 효과 역시 가져올 수 있다.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2540-2543
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• 2008

Liquid crystal displays (LCD's) are continuously coated with some chemicals in the clean room of a factory. Spreading of these chemicals is causing serious problems both in controlling clean room quality as well as to the workers inside the factory. It is required to alleviate or properly control the offensive odor which is mainly composed of propylene glycol mono ethyl acetate, novolak resin and photo active compound. The control strategy employed is to bleed the offensive odor gas out the clean room. A full scale 3D CFD model was created with anisotropic porous media, chemical species transport with no volumetric reaction, and thermal diffusion with propane gas (tracer gas) to simulate the odor spreading. A segregated implicit solver with standard k-$\varepsilon$ model is employed. The detailed CFD analysis made it possible to develop an effective method of ventilating the coater room and optimizing their capacities.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.3
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• pp.465-470
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• 2017

This paper designs and implements a smart garden system using probabilistic filter algorithm using SLAM that can be used in apartment or veranda. To do this, we used Arduino and environtal sensors, which are open hardware controllers, and designed to control and observe automatic water supply, lighting, and growth monitoring with three wireless systems (Bluetooth, Ethernet, WiFi). This system has been developed to make it possible to use it in an indoor space such as an apartment, rather than a large-scale cultivation system such as a conventional plant factory which has already been widely used. The developed system collects environmental data by using soil sensor, illuminance sensor, humidity sensor and temperature sensor as well as control through smartphone app, analyzes the collected data, and controls water pump, LED lamp, air ventilation fan and so on. As a wireless remote control method, we implemented Bluetooth, Ethernet and WiFi. Finally, it is designed for users to enable remote control and monitoring when the user is not in the house.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.9
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• pp.1189-1194
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• 2013

The Intermediate Heat Exchanger (IHX) of a Very High Temperature Reactor (VHTR) is a core component that transfers the high heat of $950^{\circ}C$ generated in the VHTR to a hydrogen production plant. The Korea Atomic Energy Research Institute manufactured a lab-scale prototype of a Printed Circuit Heat Exchanger (PCHE) as a candidate for an IHX. In this study, as a part of a high-temperature structural integrity evaluation of the lab-scale PCHE prototype made of SUS316L, we carried out high temperature structural analysis modeling and macroscopic thermal and elastic structural analysis for the lab-scale PCHE prototype under helium experimental loop (HELP) test conditions as a precedent study prior to the performance test in HELP.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.9
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• pp.1137-1143
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• 2011

The IHX (intermediate heat exchanger) of a VHTR (very high-temperature reactor) is a core component that transfers the high heat generated by the VHTR at $950^{\circ}C$ to a hydrogen production plant. Korea Atomic Energy Research Institute manufactured a small-scale prototype of a PCHE (printed circuit heat exchanger) that was being considered as a candidate for the IHX. In this study, as a part of high-temperature structural integrity evaluation of the small-scale PCHE prototype, we carried out high-temperature structural analysis modeling and macroscopic thermal and elastic structural analysis for the small-scale PCHE prototype under small-scale gas-loop test conditions. The modeling and analysis were performed as a precedent study prior to the performance test in the small-scale gas loop. The results obtained in this study will be compared with the test results for the small-scale PCHE. Moreover, these results will be used in the design of a medium-scale PCHE prototype.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.2
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• pp.113-126
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• 2009

In the recent years, health effect of dimethylformamide(DMF) has been one of critical industrial hygiene issues. There might be many factors to increase the exposure level of DMF. Among those factors, industrial ventilation would be one of the main factors. In this study, industrial ventilation systems of printing processes in synthetic leather factories were thoroughly surveyed and the improved ventilation systems were proposed. 7 synthetic leather factories were selected for this study. After the ventilation systems were visually inspected, each component of the system was tested by using the appropriate instruments. Hood face velocities, fan exhaust flow rates, fan static pressures, fan rotation rates, etc were measured. In addition, flow visualization techniques were used to observe flow patten around hoods and inside the factory buildings. After gathering all qualitative and quantitative information, the test results were analysed to see if any improvement might be necessary. For the system to be improved, the re-design plans were made by using computational fluid dynamics softwares. The softwares used in this study were AIRPAK and STAR-CD. The effectiveness of the several improvement options were tested, then the best cost effective option was selected. Finally, the standard ventilation systems were proposed to minimize the exposure levels of DMF.