• 설비공학논문집
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• 제10권5호
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• pp.640-648
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• 1998

A numerical study has been conducted to investigate the effect of inflow supply air temperature and velocity on ventilation effectiveness in an underfloor air conditioning space. A low Reynolds number k-$\varepsilon$ model is implemented to calculate steady state turbulent velocity distributions. A step-down injection method is used to calculate local and room mean ages from transient concentrations based on the concept of the age of air. Results show that there is a significant effect of Archimedes number on ventilation effectiveness especially for cooling conditions. Reynolds number shows relatively minor effect on velocity distribution and ventilation effectiveness especially for isothermal and heating conditions. It can be concluded that underfloor air conditioning system provides good ventilation characteristics for cooling conditions because of temperature stratification in the space.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2008년도 춘계학술발표대회 논문집
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• pp.111-116
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• 2008

The objective of this paper was to show the possibility of demand-controlled ventilation (DCV) using the current Korean ventilation standard for multi-purposed facilites. Two attractive DCV approaches; $CO_2$-DCV and RFID-DCV were applied to DCV simulations for a theoretical public assembly space served by a dedicated outdoor air system (DOAS) with enthalpy recovery device. A numerical model for predicting realtime occupant number, ventilation rate, and $CO_2$ concentration under given conditions was developed using a commercial equation solver program. It was found that the current ventilation standard causes unstable ventilation system control in DCV applications, especially under $CO_2$-DCV. It is because the ventilation rate (per person) used in Korea is the sum of the outdoor air required to remove or dilute air contaminants generated by both occupant and building itself, and not a pure function of occupant numbers. Finally, it makes DCV control unstable when ventilation flow is regulated only by the number of occupants. In order for solving this problem, current Korean ventilation standard was modified as a form of ASHRAE Standard 62.1-2007 showing good applicability to various DCV approaches. It was found that this modification enhances applicability of the current ventilation standard to DCV significantly.

• 설비공학논문집
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• 제6권2호
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• pp.103-109
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• 1994

An experimental study is performed on the flow characteristics of a swirl-jet diffuser for factory ventilation. Swirl number ranges from 0(nonswirl jet) to 0.6 when the angle of swirl vane is 60 degree. As swirl becomes strong, the maximum velocity in the plane perpendicular to jet axis decreases fast and the uniformity of velocity becomes good, particularly in the ventilated area. The similarity in velocity profiles has been found for axial velocity from even when swirl number equals 0.6. The flow characteristics of the swirl-jet which has the swirl number of 0.6 is thought to be the best among these three swirl numbers for factory ventilation. However, the pressure drop in the diffuser increases as the swirl becomes strong. This should be considered in the design of the total ventilation system including a duct system.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.731-736
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• 2008

There was in a building and with the technical advance for a energy saving the secret efficiency of the building improved together and continuously was come. The indoor air environment brought about the deterioration which is remarkable because of it. But time of most the indoor air environmental matter is one in the element which healthily affects biggest in the moderns who lives from the interior space. Today the plan for the air environmental maintenance which dwelling space is appropriate is demanded, is the actual condition where the method of the ventilation control which is energy saving and efficient is necessary. From the research which it sees, number of ventilation 0.7 time of the aeration which is a domestic legal baseline is excessive is judged from the research which sees, The sleep hour assumes it stays most long the hour when, number of ventilation 0 time 0.1 times 0.4 times $CO_2$ consistency measurements and analyzes number of ventilation conclusive escape. And $CO_2$ peak point control leads it decides a data, effective and it talks an energy saving circulation control method and it does to sleep.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2001년도 학술발표대회논문집
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• pp.77-82
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• 2001

This paper is contents that measure the ventilation rates and temperature by driving condition of exhaust fan, vapor, contaminant occurrence amount of carbon dioxide etc. In kitchen of apartment house. The ventilation rates in the apartment kitchen measured by Tracer Gas Method. And, temperature of when cook by gas table hood lower part 10cm and floor upside 10cm of kitchen central part, 120cm, 210cm heights measure. As ventilation rates measurement result, ventilation number of times was 0.7(number of times/hour) when did not to operate exhaust fan. but we were measured by 2.3(number of times/hour) when drove strongly. As temperature measurement result at cooking by gas table, temperature showed highest in hood lower part 10cm of case that do not operate exhaust fan. Temperature at kitchen central was most low in 10cm height in talc floor, and 210cm were measured highest. Concentration of carbon dioxide is very high by 4,350ppm after measurement time 10 minutes in state who do not operate exhaust fan at cooking by gas table.

• 한국터널지하공간학회 논문집
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• 제17권3호
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• pp.341-351
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• 2015

강우가 도로터널에 발생될 경우 공기 중 존재하는 빗방울에 의해 도로터널 내 환기력은 영향을 받을 것이라 예상되지만, 국내 도로터널 환기시스템 설계 시에는 이러한 인자가 고려되지 않은 채 설계되고 있는 실정이다. 따라서 본 연구에서는 비 강우 시와 시간 당 강우량을 변화시켜가며 강우가 도로터널 내 환기력에 미치는 영향을 3차원 수치해석 기법을 이용하여 알아본 결과 강우 시를 기준으로 시간 당 150 mm의 강우가 도로터널에 발생될 경우 도로터널 내부로 유입되는 공기의 유량은 52.34%만큼 감소되었고, 도로터널 입 출구의 압력차이는 22.22% 감소되어 나타나 강우에 의해 도로터널 내 환기력은 감소되는 것으로 나타났다. 시간당 강우량을 변화시켜가며 도로터널에 필요한 제트팬의 대수를 산정해본 결과 비 강우 시에는 12대인 반면 시간 당 강우량이 80 mm인 경우에는 16대, 150 mm 인 경우에는 17대의 제트팬이 필요한 것으로 나타나 도로터널의 환기시스템을 설계할 때에는 강우에 대한 인자가 추가되어야 한다.

• 터널과지하공간
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• 제22권5호
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• pp.365-372
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• 2012

본 논문에서는 환기구의 존재, 환기구 설치 대수, 환기구 용량, 복수 화원의 존재가 도로터널에서 발생한 차량 화재에 의한 연기 온도 분포에 미치는 영향을 평가하였다. 6개의 시나리오를 가정하였으며 FDS를 이용하여 시나리오 해석을 실시하였다. 해석 결과 환기구의 설치 대수가 증가함에 따라 연기의 온도는 감소하는 것으로 나타났지만, 환기구의 설치 대수가 2대인 경우와 3대인 경우에 온도 감소 효과는 거의 같은 것으로 나타났다. 환기구의 설치 용량은 환기구의 설치 대수 보다 연기 온도 감소에 더 큰 영향을 주는 것으로 해석되었다. 환기구가 없는 시나리오 No. 1과 복수 화원을 갖는 시나리오 No. 6를 제외한 나머지 시나리오에 대해서 해석한 결과 화원 상부에서의 연기 온도는 모두 $400^{\circ}C$ 이하로 나타났는데, 이는 화원 상부 연기층에서 발생하는 복사에 의해 화원 주변 가연물의 착화가 어렵다는 것을 나타낸다.

• 농업과학연구
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• 제40권4호
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• pp.317-323
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• 2013

This research was conducted to obtain the basic information for establishment of standard guidelines in the design and installation of roof ventilation system in single-span plastic greenhouse. To achieve this, the greenhouse structure & characteristics, cultivation status, and ventilation system were investigated for single-span greenhouse with roof ventilation system cultivating the Cucurbitaceae vegetables, watermelon, cucumber, and oriental melon. Most of single-span watermelon greenhouse in Haman and Buyeo area were a hoop-style and the ventilation system in those greenhouses mostly consisted of two different types of 'roof vent (circular or chimney type) + side vent (hole) + fan' and 'roof vent (circular type) + side vent (hole or roll-up type)'. The diameter of circular and chimney-type vent was mostly 60cm and the average number of vents was 10.5 per a bay with vent spacing of average 6.75m. The ratio of roof vent area to floor area and side vent area in the single-span watermelon greenhouse with ventilation fan were 0.46% and 7.6%, respectively. The single-span cucumber greenhouse in Haman and Changnyeong area were a gable roof type, such as even span, half span, three quarter and the 70.6% of total investigated single-span greenhouses was equipped with a roof ventilation fan while 58.8% had a circulation fan inside the greenhouse. The ratios of roof vent area to floor area in the single-span cucumber greenhouse ranged from 0.61 to 0.96% and in the case of the square roof vent, were higher than that of the circular type vent. On average, the roof ventilation fan in single-span cucumber greenhouse was equipped with the power input of 210W and maximum air volume of $85.0m^3/min$, and the number of fans was 9.75 per a bay. The number of roof vent of single-span oriental melon greenhouse with only roll-up type side vent ranged from 8 to 21 (average 14.8), which was higher than that of other Cucurbitaceae vegetables while the vent number of the greenhouse with a roof ventilation fan was average 7 per a bay.

• Journal of Advanced Marine Engineering and Technology
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• 제21권3호
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• pp.229-235
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• 1997

The comparison of radiative and convective heat transfer in a room air ventilation is investi¬gated by a numerical simulation. The room air temperature distributions with radiation are appeared more uniform than without radiation at Gr= 1460 and Re=50. The mean Nusselt number in the radiative heat transfer shows less value than convective heat transfer. The total mean Nusselt number is found Wall 1> Wall 3${\fallingdotseq}$Wall 2 7 Wall 4.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.778-783
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• 2008

In this paper, numerical method was calculated on evaluation of underground ventilation system to keep servicing a fresh air. The tunnel length for simulation is 18.2 km with various located seven ventilation shaft. Generally, owing to thermal generation in cable tunnel under about 50 m depths, cable tunnel ventilation system is more important than that of other tunnels. So, we conducted that the effects of ventilation systems was simulated depending on the difference of electrical power tunnel length, the number of shaft tunnel, forced ventilation and duct was or not. Test results show that the main conditions in order to enhance the underground cable tunnel are that ventilation systems have to be designed with forced ventilation and with duct.