• 생물환경조절학회지
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• 제7권4호
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• pp.311-323
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• 1998

현재 경북지방의 수박 및 참외재배에 가장 많이 이용되고 있는 대형터널 하우스의 온도 변화를 분석한 결과, 터널하우스 내 기온은 일몰과 함께 강하하여 외기온과 비슷한 온도를 유지하는 시간은 일몰 후 약 2시간 30분 전후로 나타났으며, 자연환기장치인 환기공 및 수동식 측창이 설치되어 재배기간중 하우스내 최고기온은 4$0^{\circ}C$ 이상 유지되지는 않았다. 하우스야간온도는 높이별 위치에 관계없이 거의 같은 온도로 유지되었으며, 재배기간중 야간온도는 외기온보다 2~3$^{\circ}C$정도 높게 유지할 수 있었지만, 외기온이 적온 이하일 때는 보온의 필요성이 있었다. 또 재배기간중 20cm 깊이의 지온은 2$0^{\circ}C$ 이상을 유지할 수 있어서 적정지온 확보에는 문제가 없었으며, 일변동폭은 3~5$^{\circ}C$ 정도이고 관수로 인한 지온저하는 5~6$^{\circ}C$ 정도였다

• 생물환경조절학회지
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• 제23권4호
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• pp.391-400
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• 2014

The number of large scale greenhouses has recently been increasing to cope with mass consumption of agricultural product. Korean government announced a new development plan for constructing greenhouse complex in reclaimed lands for the purpose of improvement in exports and activation of domestic market of agricultural product. Wind environment in the reclaimed land is totally different from that of inland area, and it can give a strong influence on ventilation performance of naturally ventilated greenhouse facilities. In this study, internal airflow analysis of naturally ventilated greenhouse built on a reclaimed land was conducted using wind tunnel and PIV for validation research. Later, the PIV measured results will be used to improve the accuracy of 3 dimensional CFD simulation in the future. Wind profile at a reclaimed land was produced using ESDU program and it was applied to the wind tunnel. The calculated error was only 5% and 0.96 of correlation coefficient, implying that the computed profiles were designed properly. From the measured results, when external wind speed changed from $1m{\cdot}s^{-1}$ to $1.5m{\cdot}s^{-1}$, air velocities inside the greenhouse which PIV measured were also increased proportionately in case of both side vent open and side-roof vent open. Considering reduced ratio of air velocity inside the greenhouse, it was measured a minimum of 40% in case of side vent and 30% in case of side-roof vent compared with external wind speed from each vent type. From the quantitative and qualitative PIV analysis, the PIV measured results indicated that there were well ventilated and stagnant areas in the greenhouse according to external wind condition as well as ventilation design.

• Journal of Biosystems Engineering
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• 제24권1호
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• pp.19-24
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• 1999

Motivated by the need for developing the more efficient lighting system for light culture of strawberries in the greenhouse, this paper aims at acquiring and suggesting more concrete and scientific foundation of illuminating position, numbers of light source by investigating the types of lighting system and illumination distribution in the greenhouse for light culture of strawberries. The results of investigation and experiment are summarized as following below: 1. The types of lighting system used in the greenhouse producing strawberries were classified as 1 line and 2 lines lighting system. 2. As for the arranging types of artificial light, 2 lines lighting system, were classified as Z-type, N-type and W-type. (Refer Fig. 3) 3. The results of illumination distribution for Z-type, N-type and W-type of 2 lines illuminating system in the greenhouse with a small size tunnel measured at the height of 1.5m from the ground with 220V, 100W lamp in 6m light gap showed that maximum illuminance are 961x, 1211x, 1251x, minimum illuminance are 4.41x, 4.71x, average illuminance are 33.71x, 43.11x, 44.51x and standard deviations are 28.31x, 35.41x, 38.31x at each types. 4. Proportion of the area below optimal illuminance to floor area at the two lines illuminating system of Z-, N-, and W-type in greenhouse were appeared as 39.4%, 26.0% and 26.3%, respectively. Also proportion of the area over optimal illuminance to floor area at the two lines illuminating system of Z-, N-, W-type in greenhouse were appeared as 16.8%, 14% and 14.7%, respectively. Thus N-type was superior to the others from the view points of optimal illumination distribution and energy saving.

• 생물환경조절학회지
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• 제5권2호
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• pp.187-193
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• 1996

여름철 고온기 참외재배시 환기방법에 따른 시설내 온도차이가 참외의 생육 및 품질에 미치는 영향을 구명하고자 측면환기공 환기구(Type 1), 측면환기공 환가+천정 환기공 환기구(Type 2) 및 권취식 환기구(Type 3)로 구분하여 시험을 실시한 결과를 요약하면 다음과 같다. 1. 환기방법별 온도의 하강효과는 Type 3이 가장 좋았고 Type 2, Type 1의 순으로 나타났다. 2. 환기방법에 따른 온도분포는 측면환기공만 있는 Type 1과 천정환기통 및 측면환기공이 있는 Type 2의 경우 환기공 및 환기통의 면적이 적어 중력환기 및 풍력환기가 미세하여 온도가 상승하였다. Type 3은 측면환기 면적이 넓어 풍력환기에 의한 공기의 유입, 유출이 쉬워 온도분포가 비교적 균일하였다. 3. 실측치를 이용하여 내외기온차이에 의한 환기량을 추정한 결과, Type 3이 Type 1 및 Type 2보다도 많음을 알 수 있었다. 4. 생육 및 상품성을 조사한 결과, Type 3이 Type 2, Type 1보다도 엽수 및 엽면적이 증가하여 생육이 양호하였고 과중, 과육두께, 기형과율, 상품과율 등 상품성도 우수하였다. 5. 수확시기별 상품수량은 각처리 공히 수확초기 보다는 후기로 갈수록 증가하였다. 특히 Type 3에서 뚜렷한 경향을 보였다.

• 생물환경조절학회지
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• 제4권1호
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• pp.1-8
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• 1995

One of the most destructive forces around greenhouses is wind. Wind loads can be obtained by multiplying velocity pressure by dimensionless wind force coefficient. Generally, wind force coefficients can be determined by wind tunnel experiments. The wind force coefficient distribution on a single - span arched greenhouse was estimated using experimental data and compared with reported values from various countries. The results obtained are as follows : 1. The coefficients obtained from this study agree with the values proposed by G. L. Nelson except about 0.5 of difference in the middle region of roof section. This discrepancy is mainly attributed to the dissimilarity of experimental conditions (or wind tunnel test such as Reynolds number, type of terrain, surface roughness of model, location of the lapping and measuring methods. 2. Considering that the wind force coefficients are varied along the height of a wall at wind direction perpendicular to wall, structural analysis using subdivided wind force coefficient distribution is more resonable for wall. 3. It is recommendable that wind force coefficient distribution on a roof should take more subdivision than the existing four equal divisions for more accurate structural design. 4. Structural design using wind forces close to real values is more advantageous in safety and expense.

• 한국농공학회지
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• 제38권2호
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• pp.145-151
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• 1996

Wind force coefficients of multi-span arched greenhouses with respect to wind direction of $0^{\circ}$ and $30^{\circ}$ were estimated to give more reasonable coefficient. The conventional and subdivided division types of wind force coefficient distribution diagrams were constructed by using the wind tunnel experimental data. Bending moments on the greenhouses were determined through structural analysis using obtained wind force coefficients, and were analyzed. Because actual wind pressure values on a face of greenhouse varied with locations, the more divisions of wind force coefficient distribution were subdivided, the better distribution type was coincided with actual state. In order to calculate the more accurate section force occurred on the arched greenhouse by the wind loads, it was recommendable that the wind force coefficient distribution should take more subdivision type. The maximum bending moment at the multi-span greenhouse frame at wind direction of $30^{\circ}$ was greater than that at O。, therefore the wind force coefficient at inclined wind direction to the wall was needed to be considered for the multi-span greenhouse structural design.

• 한국농공학회논문집
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• 제59권4호
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• pp.109-117
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• 2017

Coastal reclamation has created large flat lands, part of which is an attractive site to construct greenhouse complexes for the horticulture industry. Wind environments over these coastal lands are entirely different from those of the inland area, and demand increased structural safety. The objective of this study is to evaluate the structural safety of two single-span greenhouses, peach type and even-span type, under the wind characteristics of coastal reclaimed lands. The wind pressure coefficients acting on the walls and roofs of two greenhouses were measured by wind tunnel experiments, and those acting on the roofs were approximately two times larger than those suggested by the existing design guidelines. Consequently, structural analysis conducted by SAP2000 showed that greenhouse structures designed by the existing guidelines might lead to structural failure under coastal wind conditions because their maximum allowable wind speeds were lower than the design wind speed. Especially, the peach type greenhouse constructed in a reclaimed land could be damaged by approximately 48 % of the design wind speed and needed improvement of structural designs. This study suggested increasing the spacing of rafters with thicker pipes for the peach type greenhouse to enhance economic feasibility of the building under strong wind conditions of reclaimed lands.

• 대한토목학회논문집
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• 제36권2호
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• pp.307-315
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• 2016

국내 외 기후변화 대응 체제의 강화에 따라 전 세계적으로 온실가스 감축을 위한 노력을 기울이고 있다. 건설 분야에서는 건축물을 중심으로 온실가스 저감을 위한 연구가 활발히 이루어지고 있으나, 온실가스 이외에 지구환경에 영향을 미치는 각종 오염물질을 고려한 종합적인 환경부하 저감을 위한 연구는 다소 부족하다. 이에 본 연구에서는 NATM터널을 대상으로 LCA (Life Cycle Assessment, 전과정 평가) 방법론을 이용하여 공종별 환경부하 특성을 분석하였다. 분석 결과, 라이닝콘크리트공, 숏크리트공, 갱문 및 개착터널 등 7대 공종이 NATM터널의 주요 환경부하 공종으로 나타났으며 전체 환경부하량의 89.22%를 차지하는 것으로 나타났다. 또한 대표공종들의 연장(m)당 환경부하량을 산정하여 비교 분석한 결과 개착구간에 해당하는 갱문 및 개착터널 공종의 환경부하량이 가장 큰 것으로 나타났으며, 전체 터널 구간을 대상으로 할 경우 라이닝콘크리트공과 숏크리트공에서 환경부하량이 많이 발생하는 것으로 분석되었다. 본 연구의 결과는 설계초기단계에서 환경부하 대표공종의 물량을 개략적으로 산출하여 전체 환경부하량을 추정하는 모델 개발 시 활용할 수 있을 것으로 판단되며, 향후 친환경 SOC건설을 위한 환경부하 관리방안을 수립하는데 큰 역할을 할 것으로 기대된다.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2000년도 학술발표회 발표논문집
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• pp.315-320
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• 2000

An investigation and structural safety analysis was conducted to get the basic data for establishing maintenance strategy of pipe framed greenhouses. The number of greenhouses investigated was 108 in total. Most multi-span greenhouses had narrower width and lower height than the standard 1-2W greenhouse, and most of single-span greenhouses were tunnel type. In multi-span greenhouses, the size and interval of frameworks such as rafter, purline, column, and cross beam were mostly suitable, but frameworks of single-span greenhouses were mostly insufficient.

• 한국농공학회지
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• 제42권4호
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• pp.106-114
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• 2000

An investigation was conducted to get the basic data for establishing maintenance strategy of pipe framed greenhouses. The contents of the investigation consisted of actual state of structures, maintenance status, meteorological disaster, and corrosion characteristics of pipe framework in greenhouses. the number of greenhouses investigated was 108 in total. Most multi-span greenhouses had narrower width and lower height than the standared 1-2W greenhouse, and most of single-span greenhouses were tunnel type. In multi-span greenhouses, the size and interval of frameworks such as rafter, purline, column , and cross beam were mostly suitable, but frameworks of single-span greenhouses were mostly insufficient. After about 7 years in grounds, 8 years in joints, 10 years in bending parts. and 13 years in columns. pipe surface was mostly rusted. Most weak parts in corrosion were pipes in contact with the ground, joints, roll-up shaft pipes, and pipes close to the gutter. Almost all of the greenhouse farmers didn't pay any attention to maintenance affair in a regular interval for pipe framed grenhouses. Many greenhouses have experienced the meteorologicla diaster such as uplift of foundation, partial or complete failure by the hyphoon and/or high winds.