• 한국대기환경학회지
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• 제20권4호
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• pp.493-501
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• 2004

The principle of vortex tube and cyclone was introduced to enhance the treatment efficiency of waste air streams containing particulate matters, toluene, and others developed by Hangreen Tech, Ltd. and Hoseo Chemical and Industrial Technology R＆D Center. Adsorption, condensation, and/or coagulation could be induced at low temperature zone formed by vortex tube and Joule-Thomson expansion. The pressurized air was introduced at the tangential direction into the cyclone system applied with the coaxial funnel tube. Easily condensible vapors such as toluene. carbon dioxide, and water vapor were adsorbed enforcedly on coagulated or condensed materials which were formed as cores for coagulation or condensation by themselves. These types of coagulation or condensation rates were rapidly promoted as the diameter being growing up. The maximum removal efficiency for carbon dioxide and toluene was achieved to about 87 and 90 percent, respectively. The Joule-Thomson coefficients were increased with the pressure of air injected in the range of the relative humidities between 10% and 30%. An optimum value was observed within the range of the tested temperatures at a fixed pressure. In conclusion. it could be identified that the treatment efficiency would be depended on the pressure of the process air introduced and physical and chemical characteristics of waste air streams containing target materials for a designed system. The final design parameters should be decided depending upon the given system and target materials.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.768-773
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• 2004

When a gas expands through a convergent nozzle in which the ratio of the ambient to the stagnation pressures is higher than that of the critical one, the issuing jet from the nozzle is underexpanded. If a flat plate is placed normal to the jet at a certain distance from the nozzle, a detached shock wave is formed at a region between the nozzle exit and the plate. In general, supersonic moist air jet technologies with nonequilibrium condensation are very often applied to industrial manufacturing processes. In spite of the importance in major characteristics of the supersonic moist air jets impinging to a solid body, its qualitative characteristics can not even know. In the present study, the effect of the nonequilibrium condensation on the underexpanded moist air jet impinging on a vertical flat plate is investigated experimentally. Flow visualization and impact pressure measurement are performed for various relative humidities and flat plate positions. The obtained results show the plate shock and Mach disk are dependent on the nozzle pressure ratio and the relative humidity, but for a given nozzle pressure ratio, the diameters of the plate shock and Mach disk depend on the stagnation relative humidity. The impact pressure deviation from the flow of without condensation is large, as the relative stagnation humidity increases.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.442-447
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• 2006

In semiconductor manufacturing clean rooms, it becomes important to remove airborne molecular contaminants as well as particulate contaminant in outdoor air introduced into clean rooms. One suitable control technique for these chemical contaminants is air washing by water in an outdoor air handling unit. In order to enhance the removal efficiency of chemical contaminants the effect of adding a heating and humidifying process before an air washer was examined.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.1137-1143
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• 2006

The purpose of this research lays on examining the adequacy of the hybrid ventilation system. The hybrid ventilation system must satisfy the next to be used. Firstly, the cold-draft phenomenon must not exist in the occupied zone. Secondly, the condensation must not happen on the surfaces of vents. Thirdly, the flow of make-up air must be happened in an each space by exhausted air of a rest room and living room. We used an examination and CFD method to verify these. Trough the examination of air-vents, We confirmed that the cold-draft to be induced by make-up air does not happen and could not find the condensation in the limits of outdoor temperature higher than 265K. Through CFD simulation, We confirmed that the rapid temperature change existed only within 0.5m the occupied zone and the flow of air was happened in an each space by only exhausted air in the rest room and living room. Consequently, the hybrid system is possible method to an apartment house.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2003년도 학술대회지
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• pp.626-629
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• 2003

본 연구는 외기에 면한 초고층 아파트 최상층부의 발코니 천장내부에 있는 H-Beam(내화피복+단열재로 구성)과 Parepet 부위 내부결로 발생가능성에 대한 예측을 해 봄으로써 해당공간 거주자의 쾌적한 환경 만족 및 불안을 해소 하는데 그 목적이 있다. 외주부를 성하고 있는 Curtain wall, Stone panel 또는 슬래브 바닥하부 등의 열적 취약공간에 대해 2차원 정상상태(온도평형) 열전도해석 Program을 이용, 온도예측과 온도분포해적을 통해 해당부위의 습기압분포에 따른 내부결로 예측을 실시하였다.

• 설비공학논문집
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• 제12권1호
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• pp.20-25
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• 2000

An experimental study on the condensation heat transfer coefficients of R-22, R-290 and R-600a inside horizontal tube was performed. Heat transfer measurements were performed for smooth tube with inside diameter of 10.07 mm and outside diameter of 12.07 mm and inner grooved tube having 75 fins whose height is 0.25 mm. This study was performed for condensation temperatures were from 308 K to 323 K, and mass velocity of $51 kg/m^2s - 250kg/m^2s$. The test results showed that the local condensation heat transfer coefficients increased as the mass flux increased, and also the effect of mass flow rate on heat transfer coefficients of R-290 was less than R-22. In addition, heat transfer coefficient of R-22 increased to a larger extent than R-290 and R-600a as the mass flow rate increased. Average condensation heat transfer coefficients of natural refrigerants were superior to that of R-22. The present results had a good agreement with Cavallini-Zecchin's correlation for smooth and inner grooved tubes.

• Journal of Korean Society for Atmospheric Environment
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• 제15권E호
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• pp.29-38
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• 1999

This study identified emission sources and emissions of air pollutants such as volatile organic compounds (VOCs), solvents, and acid gases produced from chemical plants. We collected air samples from various processes, reactors and facilities using VOC detectors and workers' experience. We identified chemical structures and emission concentrations of air pollutants. We analyzed total emissions of air pollutants emitted from the chemical plants. Also, we developed some emission reduction technologies based on chemical types and emission situations of the identified air pollutants. For reduction of air emissions of acid gases, we employed a method improving solubility of pollutants by reducing scrubber operation temperature, increasing surface area for effective contact of gas and liquid, and modifying or changing chemicals used in the acid scrubbers. In order to reduce air emissions of both amines and acid gases, which have had different emission sources each other but treated by one scrubber, we first could separate gas components. And then different control techniques based on components of pollutants were applied to the emission sources. That is, we first applied condensation and then acid scrubbing method using H2SO4 solution for amine treatment. However, we only used an acid scrubbing method using H2O and NaOH solution for acid gas treatment. In order to reduce air emissions of solvents such as dimethylformamide and toluene, we applied condensation and activated carbon adsorption. In order to reduce air emissions of mixture gases containing acid gases and slovents, which could not be separated in the processes, we employed a combination of various air pollution control devices. That is, the mixture gases were passed into the first condenser, the acid scrubber, the second condenser, and the activated carbon adsorption tower in sequence. In addition, for improvement of condensation efficiency of VOCs, we changed the type of the condensers attached in the reactors as a control device modification. Finally, we could successfully reduce air emissions of pollutants produced from various chenmical processes or facilities by use of proper control methods according to the types and specific emission situations of pollutants.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.460-463
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• 2008

the present study, the addresses the hysteric phenomenon of under-expanded jets with a help of a computational fluid dynamics methods. The under-expanded jets of both dry and moist air have been employed to the transient processes for the pressure ratio. It is known that under-expanded air jet produced during the process of increase in pressure ratio behaves different from the reducing process, leading to a hysteric phenomenon of under-expanded jet. It is also known that moist air jet significantly reduces the hysteric phenomenon found in the dry air jet, and that non-equilibrium condensation which occurs in the under-expanded moist air jet is responsible for these findings.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 추계 학술논문 발표대회
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• pp.17-18
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• 2012

Moisture condensation leading to defects that occur repeatedly in the winter, and recognize the same method, the problem of the other buildings in the same area again and again, a vicious cycle that occurs due to the temporary lack of systematic research and processing way of coping has been recurring. In this study, as warming progresses, more inside the air-conditioned summer season due to an increase in the ambient temperature of the condensation phenomenon to happen about summer wall condensation phenomena are expected to analyze the case of a building to prevent condensation and for insulation designs are proposed.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.1255-1260
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• 2006

This present study analyzed temperature depreciation ratio of window inside surface by KS F 2295 'Procedure for determining fenestration product condensation resistance values'. it estimated window indoor surface condensation due to variable environmental condition. Performance of condensation resistance by using temperature depreciation ratio until applied Low-e and Ar glazing improved about 45% from 24 mm clear. Temperature depreciation ratio by KS F 2295 considers analytic index of window condensation due to variable boundary condition.