• 설비공학논문집
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• 제17권10호
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• pp.922-929
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• 2005

This paper compared ventilation performance between the sound roof tunnel with flat roof and the sound roof tunnel with gable roof. The ventilation rate of the sound roof tunnel is calculated by natural ventilation rate plus ventilation by vehicle. The roof type is divided by the shape of the roof and the ventilator location on the roof. The results between calculation and CFD on the ventilation rate are almost alike. The ventilation rate on the flat roof is $558.4\;m^3/s$ with mid-ventilator and $496.8\;m^3/s$ with left-right ventilator. The ventilation rate on the gable roof is $653.2\;m^3/s$ with mid-ventilator and $611.6\;m^3/s$ with left-right ventilator. The ventilation rate of soundproof with gable roof is higher than that with flat roof. The ventilation rate and with mid-ventilator is higher than that with left-right ventilator the soundproof roof. Therefore, the ventilation performance of soundproof roof depends on the roof shape and ventilator location on the roof.

• 설비공학논문집
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• 제20권2호
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• pp.121-127
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• 2008

This paper investigates the effects of outdoor pressure fluctuations on natural ventilation through an opening on a building envelope. The ventilation airflow rate depends on the magnitude and the period of the pressure fluctuations, the size of the opening relative to the space volume, and the resistance characteristics of the opening. Non-dimensional parameters have been derived, which determine indoor pressure responses due to outdoor pressure fluctuations. The flow regions are categorized into (1) synchronized region, (2) opening resistance region, and (3) transition region depending on the non-dimensional parameter derived. Pressure fluctuations and flow characteristics are investigated numerically using the 4th order Runge-Kutta method.

• 한국태양에너지학회 논문집
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• 제22권4호
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• pp.68-76
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• 2002

This paper discusses thermal and ventilation performance which might be caused by the adoption of one of specific building facade techniques, Double Skin System(DSS). One building with a prototypical DSS was selected and systematically investigated through field monitoring and computer simulation techniques. A network model of ventilation was successfully made using COMIS to evaluate ventilation performance of the system which can hardly be done by field measurements. Various operating conditions of air conditioning on/off and window opening were implemented in this type of building. Through the appropriate operation of the DSS in summer, simulation-based and experimental results implicate that it can lead to cooling energy savings.

• 원예과학기술지
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• 제34권6호
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• pp.845-859
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• 2016

본 연구는 스탠다드 국화 '백마'의 시설재배에 있어서 야간 환기 방법과 난방처리 조건에 따른 온습도의 변화, 흰녹병 발생 및 절화의 생육에 미치는지 영향을 알아보고자 수행되었다. 환기 방법에 관한 실험에서 측창을 밀폐시킨 대조구의 평균 상대습도 94.5%에 비해 자연환기는 74.3%, 자연+Fan환기 처리구에서는 72.8%로 낮았다. 흰녹병 발생률은 대조구 100%, Fan환기 98.3%, 자연환기 75.6%, 자연+Fan환기 처리구에서 43.4%로 나타났다. 또한 발병엽수와 동포자퇴수도 다른 처리들보다 자연+Fan환기 처리는 가장 적었다. 대조구에서는 과습과 흰녹병 발생으로 절화의 생육이 크게 억제되었는데, 자연+Fan환기 처리구는 초장, 엽수, 줄기직경, 절화의 생체중 등 절화의 생육이 양호하였다. 난방 조건에 따른 시설 내의 야간 평균 온도는 대조구인 RH 95% 난방처리에서 $18.4^{\circ}C$ 인데 반하여 RH 70% 난방처리에서 $25.8^{\circ}C$ 로 나타나 $7.4^{\circ}C$ 상승하였다. RH 70% 난방처리에서도 흰녹병 발생률 34.4%, 주당 발병엽수 0.9개, 발병엽당 동포자퇴수 1.0개로 대조구보다 흰녹병 발생이 크게 억제되었다. 또한 RH 70% 난방 처리구에서 습도가 높은 대조구보다 초장, 엽수, 줄기직경, 생체중 등 절화의 생육이 양호하였다. 따라서 시설 내에서 국화 '백마'를 재배시 자연+Fan환기와 난방처리는 흰녹병을 크게 억제할 수 있을 뿐만 아니라 절화의 생육에도 효과적이었다.

• 한국터널지하공간학회 논문집
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• 제11권4호
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• pp.395-401
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• 2009

장대터널의 환기 및 방재시스템 설계시 주요한 요소설계인자 중 하나인 자연환기력은 그 중요성에도 불구하고 관련 영향변수들의 상호관계는 정량화가 매우 복잡하여, 자연환기력에 의한 유입 자연풍에 관한 설계기준을 정량적 근거하에서 제시하고 있지 못하다. 최근 발생한 터널화재에 의한 문제 및 터널 이용자에 의한 보다 나은 공기질에 대한 요구 등으로 터널 환기시스템의 최적화가 시급히 필요하며, 따라서 최적화의 주요 설계인자인 자연환기력에 대한 연구가 절실히 요구된다. 본 연구에서는 국내 최장대 도로터널로 계획된 인제터널(연장 10.9 km)을 대상으로 자연환기력의 예측을 목적으로 하였다. 지형적 요인에 의한 외부풍의 풍압에 기인하는 자연환기력의 최대 가능수준을 예측할 수 있는 기압장벽고의 개념을 적용하여 외부풍에 의한 자연환기력을 추정하고 터널내외부 공기 밀도차로 인한 굴뚝효과에 따른 자연환기력을 동시에 분석하였다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.80-83
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• 2008

As SOC (Social Overhead Capital) has been expanded, the highway road construction has been accelerated and city road system has been more complicated. So, long road tunnels have been increased and traffic flow rate also has been raised. Accordingly, the exhausting gas of vehicle cars seriously deteriorates the tunnel inside air quality and driving view. In order to improve tunnel inside air quality, we may need to introduce a compulsory ventilation system as well as natural ventilation mechanism. The natural ventilation mechanism is enough for short tunnels, meanwhile longer tunnels require a specific compulsory ventilation facility. Many foreign countries already have been devoting on development of effective tunnel ventilation system and especially, some European nations and Japan have already applied their developed tunnel ventilation system for longer road tunnels. More recently, as the quality of life improved, our concerns about safety of driving and better driving environment have been increased. In order to obtain clearer and longer driving view, we are more interested in EP tunnel ventilation system in order to remove floating contaminants and automobile exhaust gas. Evan though it's been a long time since many European countries and Japan applied more economical and environment-friendly tunnel ventilation system with their self-developed Electrostatic Precipitator, we are still dependant on imported system from foreign nations. Therefore, we need to develop our unique technical know-how for optimum design tools through validity investigation and continuous possibility examination, eventually in order to localize the tunnel ventilation system technology. In this project, we will manufacture test-run products to examine the performance of system in order to develop main parts of tunnel ventilation system such as electrostatic precipitator, high voltage power generator, water treatment system, etc.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.965-968
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• 2007

Two major parameters, i.e. carbon dioxide ($CO_2$) and particulate matters smaller than $10{\mu}m\;(PM_{10})$, were selected as the index pollutants in managing indoor air quality. The former pollutant, $CO_2$, is the index that shows the ventilation status and is exhaled by passengers when they breathe in train or subway. It is generally known that high $CO_2$ concentration in the vehicle may be decreased by insufficient air-tightening vehicle bodies and the air is ventilated when vehicles stop at the station and doors open. However, there is no established proof or quantitatively identified data on how much the $CO_2$ concentration is reduced when ventilation is done while doors are opened. In this study, $CO_2$ concentrations were measured in 6 lines of Korail and one line of Seoul Metro subway linesand a theoretical approach was takento predict the changing trend of $CO_2$ concentrations during the operation of vehicle by using $CO_2$ dilution factor through natural ventilation. As a result, the change could be quantified and it was found that app. 35% of indoor $CO_2$ was removed through natural ventilation.

• KIEAE Journal
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• 제10권5호
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• pp.87-93
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• 2010

The objective of this study is to verify the safety in case of fire and change of residential environment for different wall construction approaches in a stairways apartment house. In order to confirm that case_1, which is current case that most of wall is opened and the case 2, which upper part of wall is limitedly opened are compared and analyzed based on simulations of fire, escape and natural ventilation performance. The analysis reveals that possible escape time for case 1 was more than 600 seconds and for case 2 was 195 seconds. Since the escape times for both cases were over 128 seconds, it would be reasonable to assume that every resident would escape. The simulation results on natural ventilation performance shows the air change per hour of case 1 and case 2 were .19n/h and .16n/h and there was 1.2 times difference. However, the difference was too insignificant and it could be seen as that different approaches on wall construction would not significantly influence on natural ventilation performance.

• 한국가스학회지
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• 제6권1호
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• pp.74-80
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• 2002

지하공간에서 천연가스가 고압으로 분출될 때, 이에 응하여 작동되는 환기시스템이 전체 지하공간 내 유동에 미치는 영향은 매우 크며 이에 대한 적정한 선계는 안전성 확보측면에서 매우 중요한 일이다. 본 연구에서는 천연가스 분출 비상시의 유동을 전산해석을 통하여 반밀폐공간 내 천연가스의 농도분포 및 유동특성을 규명함으로써, 내부유동을 가시화하고 상부 환기팬 유$\cdot$무에 따른 환기효율을 비교함으로써 환기시스템의 개선사항 및 설계 방안을 제시하였다.

• Structural Engineering and Mechanics
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• 제88권6호
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• pp.521-533
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• 2023

In the present study, the finite volume method is applied for the thermal performance prediction of the natural ventilation system using vertical solar chimney whereas, design parameters are optimized through the response surface methodology (RSM). The computational simulations are performed for various parameters of the solar chimney such as absorber temperature (40≤T_abs≤70℃), inlet temperature (20≤T₀≤30℃), inlet height of (0.1≤h≤0.2 m) and chimney width (0.1≤d≤0.2 m). Analysis of variance (ANOVA) was carried out to identify the design parameters that influence the average Nusselt number (Nu) and mass flow rate (ṁ). Then, quadratic polynomial regression models were developed to predict of all the response parameters. Consequently, numerical and graphical optimizations were performed to achieve multi-objective optimization for the desired criteria. According to the desirability function approach, it can be seen that the optimum objective functions are Nu=25.67 and ṁ=24.68 kg/h·m, corresponding to design parameters h=0.18 m, d=0.2 m, T_abs=46.81℃ and T₀=20℃. The optimal ventilation flow rate is enhanced by about 96.65% compared to the minimum ventilation rate, while solar energy consumption is reduced by 49.54% compared to the maximum ventilation rate.