• 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.

• 설비공학논문집
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• 제24권2호
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• pp.136-141
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• 2012

Performance improvement of local exhaust system used in toilet and cooking place are main concern in a field of ventilation. In Korea, There are many high riser residential apartments in recent years. These buildings were not viewed as being major contributors to exhaust pollutants producted in indoor. It was because many engineers thought that exhaust in high riser building depends on stack effect. This study investigates on the performance improvement of terminal device, roof fan, of vertical spiral duct used in high riser residential apartments. This paper focuses mainly on the effect of accessories, number or shape of blades, composed of roof fan with function of exhaust air volume of toilet and cooking place. Roof fan with 10 blades is observed at optimum exhaust performance in this study.

• 설비공학논문집
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• 제23권2호
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• pp.139-146
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• 2011

The ventilation performance of a vertical exhaust duct system in the high riser public house has been evaluated by a commercial software, Fluid Flow, which solves pressure losses through the duct system including bathroom fans and a hybrid roof fan. During the numerical simulations, outdoor wind condition and stack effects in summer and winter were considered as well as the operating conditions of a basement damper and the roof fan. The results show that the bathroom ventilation in summer is the most unsatisfactory. The opening of the basement damper has a problem that the polluted air in the lower floors is exhausted to the underground parking lot, not to the rooftop. If the basement damper is closed, the exhaust flow rate in the lower floors is not sufficient due to the strong flow resistance in the long vertical duct even though the roof fan is under operating.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.889-894
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• 2008

Exhaust system used in toilet and cooking place of high riser public house is roof fan of two basic types : natural roof ventilator and natural/forced roof ventilator. Natural/forced roof ventilator has a motor in the rotary shaft. There are many high riser public house in Korea. These buildings were not viewed as being major contributors to exhaust pollutants producted in indoor. It was because many engineers thought that exhaust in high riser building depend on stack effect. This study investigates on stack pressure determined by exterior pressure and the difference pressure control in exhaust stack used in high riser public house. This paper focuses mainly on the effect of the time interval for power supply of motor installed in roof fan with function of natural wind velocity and of exhaust air volume of toilet. It is observed there are higher exhaust efficiency than the existing natural roof ventilator.

• 생물환경조절학회지
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• 제25권4호
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• pp.334-342
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• 2016

지붕 환기장치 설치방법의 개선에 의한 작물 재배효과를 검증하고자 농가현장에서 개선 지붕 환기방식과 관행환기방식을 비교, 분석하였다. 개선 지붕 환기방식은 참외재배 단동 플라스틱 온실(폭 5.6m, 길이 108m, 측고 1.1m, 동고 2.2m)에 지붕 환기팬(용량 $38m^3/min$)과 환기통(지름 60cm)을 각각 15m와 6m 간격으로 설치하였고, 대조구로서 관행 지붕 환기방식은 각각 20m와 8m 간격으로 설치하였다. 관행 및 개선 지붕 환기 방식에 따른 생육을 조사한 결과, 관행 환기통과 환기팬 처리에 비해 개선 환기통과 개선 환기팬 처리에서 경경, 엽장, 엽병장, 및 엽폭의 값이 낮게 나타나는 경향을 보였다. 생육기 전반부에 관행 환기통 처리는 환기팬 처리에 비해 절간장이 다소 길게 발달하였는데 이는 착과수가 환기팬 처리에 비해 적었고, 착과수 감소로 인해 동화산물이 잎과 줄기의 신장부로 좀 더 이동된 영향으로 판단되었다. 참외재배 단동 비닐하우스에서 과실 수량을 조사한 결과, 개선 환기팬과 개선 환기통 처리는 관행처리에 비해 과중은 약간 작았지만, 착과수 증가로 인해 전체 수량은 높게 나타났다. 개선 환기팬과 개선 환기통 설치 하우스에서는 관행 지붕 환기 하우스에 비해 상품과율이 높았으며, 10a당 상품수량도 각각 8,391kg, 7,283kg 으로 나타나 관행 지붕 환기에 비해 개선 환기팬 처리는 661kg, 개선 환기통 처리는 487kg 더 증가하였다. 개선 환기팬 처리는 고온기에 암꽃수와 착과수가 가장 많았고, 낙과수는 가장 낮게 나타났으며, 관행의 환기통 처리에 비해 과실의 크기는 작았다. 시기별 환기방식에 따른 참외 과실의 품질을 조사한 결과, 관행 환기통 환기에서 과중, 과경, 과폭, 및 과육두께가 가장 높게 나타났으나, 과폭, 과육두께에 있어서 통계적인 유의차는 나타나지 않았다.

• 유기물자원화
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• 제22권3호
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• pp.60-67
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• 2014

고층 공공주택의 화장실과 주방에 적용되는 배기 시스템은 기본적으로 두 종류의 환기팬이 적용된다. 가지 기본 유형의 지붕 팬이다. 그 하나가 자연 통풍력을 활용하는 무동력 팬이고 다른 하나는 자연 통풍력이 없을 때, 모터를 활용하여 강제로 구동하는 팬을 적용하는 방식이다. 자연/강제 겸용으로 지붕에 적용되는 환기팬은 회전축에 모터가 있습니다. 대한민국에는 많은 고층건물이 있다. 그러나 고층건물의 환기가 굴뚝효과에 의존된다고 판단하였기 때문에 이러한 건물의 실내에서 발생하는 오염물질의 제거에 대한 관심을 크게 갖지 않고 있다. 본 연구는 외기압력과 초고층아파트에 사용되는 배기연돌에 적용되는 차압에 의해 결정되는 연돌압력을 조사하기 위함이다. 본 논문은 화장실 배기풍량과 대기의 자연풍속을 변수로 하여 루프팬에 설치된 모타의 전력공급시간을 판단함으로써 기존 배기팬보다 향상된 배기효율을 예측하기 위해, 수행되었다.

• Wind and Structures
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• 제19권1호
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• pp.15-33
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• 2014

This paper describes partial turbulence simulation and validation of the aerodynamic pressures on building models for an open-jet small-scale 12-Fan Wall of Wind (WOW) facility against their counterparts in a boundary-layer wind tunnel. The wind characteristics pertained to the Atmospheric Boundary Layer (ABL) mean wind speed profile and turbulent fluctuations simulated in the facility. Both in the wind tunnel and the small-scale 12-Fan WOW these wind characteristics were produced by using spires and roughness elements. It is emphasized in the paper that proper spectral density parameterization is required to simulate turbulent fluctuations correctly. Partial turbulence considering only high frequency part of the turbulent fluctuations spectrum was simulated in the small-scale 12-Fan WOW. For the validation of aerodynamic pressures a series of tests were conducted in both wind tunnel and the small-scale 12-fan WOW facilities on low-rise buildings including two gable roof and two hip roof buildings with two different slopes. Testing was performed to investigate the mean and peak pressure coefficients at various locations on the roofs including near the corners, edges, ridge and hip lines. The pressure coefficients comparisons showed that open-jet testing facility flows with partial simulations of ABL spectrum are capable of inducing pressures on low-rise buildings that reasonably agree with their boundary-layer wind tunnel counterparts.

• 농업과학연구
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• 제42권4호
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• pp.325-333
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• 2015

The ventilation systems composed three types of side vent (roll-up) 'SV', side vent+roof vent 'SV+RV', and side vent+roof fan 'SV+RF' with 7.5 m spacing, with specific set point temperatures for ventilation: SV ($35^{\circ}C$ open / $33^{\circ}C$ close), SV+RV or SV+RH ($35^{\circ}C$ open/$33^{\circ}C$ close for root ventilation and $37^{\circ}C$ open / $35^{\circ}C$ close for side vent). In the treatment of SV+RV, although the average daily maximum temperature inside the greenhouse temporarily increased by $38-40^{\circ}C$, thermal stress by high temperature did not occur and the disease incidence (%) of powdery mildew and downy mildew on the oriental melon were 25 - 75% lower than in the conventional SV treatment. In the SV treatment, the disease incidence (%) of powdery mildew and downy mildew were 1.4 - 7.7% and 4.2 - 15.9% for 'Deabakkul', and 20.3 - 22.8% and 2.8 - 11.3%, for 'Ildeungkkul'. The yield for one month was higher in the treatment of SV+RV than those in other treatments, with values of 2,105 kg/10a for 'Deabakkul' and 2,537 kg/10a for 'Ildeungkkul'. The simultaneous treatment with side vent and roof vent resulted in 16.2% higher yield (18.1% higher marketable yield) than that in the SV treatment for 'Deabakkul'.

• 건축역사연구
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• 제21권2호
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• pp.21-36
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• 2012

As wooden construction developed, it was observed that the rafters with corners changed to angled rafters. The change from rafters to angle rafters means that the angle rafters became the most important member in supporting the roof weight as the construction scale increased and structurally developed. The specific installation methods of angle rafters were all unique in Korea, China, and Japan. In East Asia, the angle of the angle rafter gradually decreased along with the development of construction. However, in Joseon Dynasty Korea, the angle of the angle rafter was larger than that of the Gorye era because the method of fixing the corner of the roof more firmly by building the fan-shaped rafter was utilized. The changes to the angle rafter installation method is a unique characteristic of Korea, in that it was developed in a totally different way from the methods used in China and Japan.

• 한국축산시설환경학회지
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• 제4권1호
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• pp.1-8
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• 1998

The objective of this study was conducted to develope a mobile pig nursery(MPN) for segregation of early weaned piglet. The units of MPN was consisted of 4 rectangle-type pens, 1 workroom, 2 doors, 3 windows, 1 air-inlet, 1 exhaust fan, and 1 cooling and heating system. Total of 40 piglet were weaned at 7 days of age. The period of the feeding test was 63 days. The results obtained are as follows: 1. The insulation thickness was 70, 70 and 50 mm of roof, floor and wall, respectively. R-value was 15.32 and 10.32 of roof and wall, respectively. 2. Exhaust fan( 30.48) was installed near back door 40cm from the bottom. When exhaust fan speeds were 15, 20, 30 and 35%, Air ventilation was required 9.75, 7.07, 1.72, 1.45 minutes of respectively. 3. Average temperature in the MPN was able to maintain 27∼28$^{\circ}C$ from 7∼28 days of age, 24∼25$^{\circ}C$ from 35∼56 days of age and 20∼21.5$^{\circ}C$ from 56∼70 days of age. 4. Average daily gain, feed intake and feed conversion were 420.6g, 761.5g, 1.81 respectively.