• Journal of Mechanical Science and Technology
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• 제14권11호
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• pp.1286-1295
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• 2000

The ventilation effectiveness is evaluated as a function of air exchange rate and supply / extract locations in a simplified model chamber using a tracer gas technique of CO$_2$ gas injected into a supply duct. Ventilation systems consist of supply and extract fans, a CO$_2$gas generator, a CO$_2$gas analyzer and a test chamber. The ventilation effectiveness is evaluated using a step-down method based on ASTM Standard E741-83. The room mean age of the model chamber is decreased with increasing air exchange rate fanged from 6to 10 air changes per hour. The ventilation effectiveness of the mechanical inlet/natural extract system is better than that of the mechanical extract system.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 동계학술발표대회 논문집
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• pp.33-38
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• 2005

A hybrid ventilation system was introduced to predict the ventilation performance of the apartments. This ventilation system was composed of the natural supply-air inlet and the forced exhaust-air outlet. Analysis was conducted by CFD technique and was performed on three ventilating flow rates; 30, 60, 120 $m^3/h$. As the results, residents feel comfortable thermally and in air flow conditions for 60 $m^3/h$. But the case of 30 $m^3/h$ shows 1100ppm of $CO_2$ concentration due to the deficient of air flow rate. In the case of 120 $m^3/h$, however, residents feel uncomfortable thermally and in air currents. In this study the energy saving for space heating is also an important factor. A detailed prediction for more complicated whole apartment space will be investigated in the future.

• 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.

• 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.

• 한국환경과학회지
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• 제7권3호
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• pp.327-334
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• 1998

The oil crisis of the 1970s and the rise in oil prices motivated people to implement energy conservation strategies. Buildings were fitted with additional Insulation and reduced ventilation rates. The reduction of mechanical and natural ventilation rate led to Increases In Indoor pollutant concentrations which result- ed In Increased health risks from Indoor exposure to pollutants. The variable-air-volume /bypass fitration system/VAV/BPFS) is a variation of the conventional VAV systems, The VAV/BPFS is an electronically controlled system that provides costegectlve thermal comfort and acceptable indoor air quality Under controlled conditions In a chamber, a series experiments were performed to compare the ability of a VAV/BPFS to remove Indoor aerosol concentration and to reduce energy consumption no that ability of conventional VAV system. Results show that the VAV/BPFS Increases the effective ventilation rate and removes indoor air pollutant, and maintains acceptable indoor air Quality without sacrificing energy consumption.

• KIEAE Journal
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• 제4권3호
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• pp.195-202
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• 2004

This study focuses on the impacts of apartment building arrangements on the outdoor and indoor air quality - the efficiency of natural ventilation in the outside/inside area of an apartment with consideration to the characteristics of an air flow in outside area depending on the types of the arrangements, the main direction of the wind, and the outside wind pressure on the building facade. As indices to evaluate the efficiency of natural ventilation, the concepts of "Age of Air" and "Purging Flow Rate(PFR)" were used in this study. As indices to classify the efficiency of indoor natural ventilation, the mean values of the wind pressure differences between the front and the back elevations of an apartment building were used. The research showed that the PFR of each apartment building arrangement ranges from 0.867 to 3.253. The "minus-shaped" arrangement showed the highest PFR, 2.306; the "zigzag-shaped" arrangement measured 1.889; the "angle-shaped" arrangement measured 1.465, and the "square-shaped" arrangement measured 1.241. Depending on the direction of the wind, the pressure differences range extremely, with variations from 170% to 2300%. Thus, the indoor natural ventilation efficiency can be changed by the pressure differences of the wind, which are sensitive to the main direction of the wind even though the structure and planning of the apartment complexes are the same. Despite the same direction of the wind, even the efficiency can be diverse. This study showed how to predict the most beneficial apartment building arrangement for the profitable natural ventilation efficiency in each direction of the wind.

• 대한환경공학회지
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• 제31권7호
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• pp.521-530
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• 2009

본 연구에서는 대전의 대규모 공동주택단지의 하나인 대덕테크노 밸리의 계절별 주풍향 및 풍속, 건물배치, 환기구 위치 등 다양한 외부 유동 변수에 따른 실내 환기 특성을 수치 해석적 방법을 활용하여 연구함으로써 실내 공기질 향상에 일조하기 위해 연구를 수행하였다. 계절별 주풍향은 여름과 겨울에 큰 차이를 나타냈는데, 여름철의 경우 주풍향은 남풍이며, 겨울철의 경우 주풍향은 10년 평균 주풍향과 동일한 북북서풍으로 나타났다. 풍향이 변화함에 따라 최대 압력차가 나타나는 단지도 변화하였으며 그에 따라 환기에도 차이를 나타냈다. 내부 환기량은 환기 우수지역의 경우는 자연환기만으로 기준치인 시간당 0.7ACH를 만족하였으나 환기 취약지역의 경우는 자연환기만으로는 기준치를 만족시키지 못하여 부수적으로 기계 환기를 병행해야 하는 것으로 나타났다. 이러한 외부유동 변화에 따른 내부 환기량의 연구결과를 바탕으로 향후 아파트의 배치나 환기구 위치 선정에 응용한다면 환기량 확보에 일조하여 기계환기에만 의존하지 않고 자연환기와 병행이 가능하므로 에너지 절감에 도움이 될 것으로 판단된다.

• 한국가스학회지
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• 제16권4호
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• pp.23-31
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• 2012

밀폐 공간 내의 천연가스 공급 시스템에서 가스 누설에 따른 재난을 방지하고 보다 안전한 설계를 하기 위해서는 누출된 천연가스의 확산거동을 이해하고 예측할 수 있는 기술이 필요하다. 본 연구에서는 CFD를 사용한 해석법을 제시하고, 기 수행된 British Gas Technology Co.의 실험결과와 비교하여 타당성을 제시하였다. 노즐에서의 분출유량 2D 해석 결과는 실험결과와 2.6% 이내로 잘 일치함을 보였다. 또한, 다양한 강제 환기 조건에 따른 가스 확산 특성을 비정상상태 3차원 CFD 해석을 수행한 결과 실험결과와 정성적인 경향이 잘 일치됨을 보였다.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 춘계학술발표대회 논문집
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• pp.174-178
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• 2011

This paper deals with the free cooling system of express bus using natural energy source in order to improve the room air quality and save cooling energy. In an express bus, there are may passengers in unit area, requiring the improvement of air quality and giving higher energy saving efficiency. Particularly, the express buses running fast make it easy to take in outdoor air at a flow rate controllable with a damper mechanism. This paper proposes the analysis on the air flow achieved by a damper controlled vertically and horizontally in order not to deteriorate the ride comfort of the passengers.

• KIEAE Journal
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• 제5권3호
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• pp.11-16
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• 2005

The recent trends of high-density and high-rise in apartment housing have caused the problems of decrease in ventilation rates and increase of indoor pollutant contaminants. SHS(Sick House Syndrome) has now become a major issue and threats the health of residents. To solve these indoor air problems, increase in ventilation rate is considered as one of the most efficient approach. Thus, the recent housing development is pursuing improvement in the site design and the layout of apartment building blocks to promote natural ventilation is now investigated as one of the fundamental solutions. This study was focused on the air flow characteristics of outdoor environment in an apartment complex to keep the pollutants out of the site. Age of air and pressure difference have been used as indices of the outdoor air quality. Four different types of apartment building layouts have been analyzed by CFD simulation. This study again selected a real apartment housing complex as a case study model. By analyzing the pressure differences between the front and rear of an apartment building block, the ventilation performance in each individual unit was evaluated, and its impact on ventilation performance is investigated by analyzing the stagnant air around the apartment building blocks. During this process, existing patterns of apartment housing layout have been evaluated, and the most appropriate site layout has been chosen to analyze the outdoor airflow patterns. Based on the analysis of airflow patterns of site layout, the possibilities of improving ventilation performance of an individual apartment housing is proposed.