• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2001.04b
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• pp.27-28
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• 2001

온실의 차광설계에 필요한 기초자료를 제시하기 위하여 온실모형과 실험온실을 이용하여 외부차광재의 적정 설치간격 분석, 차광재별 광투과율 분석, 차광율에 따른 온실내부온도의 변화 분석, 차광이 온실내부의 지온변화에 미치는 영향분석 및 외부차광과 내부차광의 차광효과 비교를 실시하였다. 외부경사차광시 온실 지붕과 차광재의 설치간격은 10-30cm에서 차광효율이 가장 좋은 것으로 나타났으나 환기창의 개폐를 위한 공간이 필요하지 않는 온실에서는 10cm 정도이면 충분한 간격이 될 것으로 판단된. (중략)

• Journal of Bio-Environment Control
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• v.10 no.2
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• pp.80-87
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• 2001

This study was conducted to provide basic data for the design of shading facility of greenhouse. The proper distance between external shading screen and roof surface, transmissivity of shading materials, and shading effects of external and internal shadings were analyzed. About a distance of 10 cm between inclined external shading screen and roof surface was enough to guarantee the external shading effect in the greenhouse without roof vent. The inside temperature of greenhouse installed with 85% internal shading screen was lower the maximum of 4$^{\circ}C$ and mean of 2$^{\circ}C$ than that with 55% internal shading screen in both natural ventilation and no ventilation condition. The difference of soil temperature between shading and no shading greenhouse was great, but the difference by shading rate or shading method was small. The performance of external shading for controlling inside temperature down was superior to that of the internal shading. The externally inclined shading screen parallel to the roof surface of greenhouse was more effective than the externally horizontal shading screen in controlling inside temperature of greenhouse without roof vent.

• Journal of Bio-Environment Control
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• v.22 no.3
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• pp.270-278
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• 2013

The objective of the present study is to provide data needed to decide covering method to be able to increase the thermal insulation and light transmittance efficiency of commercial greenhouse. The thermal insulation effect, PPF transmittance and quantity of condensation water were estimated in experimental tomato greenhouses covered with three types of coverings of single layer, air inflated and conventional double layers covering. The overall heat flow of air inflated double layers greenhouse was similar to that of conventional double layers greenhouse, but the temperature between covering material and thermal screen in air inflated double layers greenhouse was lower than that in conventional double layers greenhouse at the same outside temperature condition due to air leakage through the gap of roof vent. The overall heat transfer coefficients acquired by experiment that was performed in single layer and conventional double layers greenhouses were close to those obtained from model experiment. Even though the PPF transmittance of air inflated double layers greenhouse was lower than that of single layer greenhouse, which was greater than that of conventional double layers greenhouse. The quantity of condensation water on covering surface of single layer greenhouse was greater than that of air inflated double layers greenhouse due to lower covering surface temperature.

• Journal of Bio-Environment Control
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• v.24 no.3
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• pp.147-152
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• 2015

In order to develop the cooling load estimation method in the greenhouse, the cooling load calculation formula based on the heat balance method was constructed and verified by the actual cooling load measured in the fog cooling greenhouse. To examine the ventilation heat transfer in the cooling load calculation formula, we measured ventilation rates in the experimental greenhouse which a cooling system was not operated. The ventilation heat transfer by a heat balance method showed a relatively good agreement. Evaporation efficiencies of the two-fluid fogging system were a range of 0.3 to 0.94, average 0.67, and it showed that they increased as the ventilation rate increased. We measured thermal environments in a fog cooling greenhouse, and calculated cooling load by heat balance equation. Also we calculated evaporative cooling energy by measuring the sprayed amount in the fogging system. And by comparing those two results, we could verify that the calculated and the measured cooling load showed a relatively similar trend. When the cooling load was low, the measured value was slightly larger than calculated, when the cooling load was high, it has been found to be smaller than calculated. In designing the greenhouse cooling system, the capacity of cooling equipment is determined by the maximum cooling load. We have to consider the safety factor when installed capacity is estimated, so a cooling load calculation method presented in this study could be applied to the greenhouse environmental design.

• Journal of Bio-Environment Control
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• v.18 no.3
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• pp.185-191
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• 2009

The construction of experimental greenhouses, operating test, and analysis on variation of different environment factors were conducted to provide fundamental data for design of Korean style air-inflated double-layer plastic greenhouse. The development of technology of attaching plastic to the structure and fasteners to be able to keep airtight was required in order to maintain proper static pressure in air space of double layer coverings. The insulation effect of air inflated greenhouse was better than conventional type. The temperature of arch type roof was greater about $2^{\circ}C$ than peach type roof in air inflated greenhouse. It was recommended that the plastic should be attached at the edges without clearance length in order to ease installation and raise airtightness of double layer coverings. The transmittance of arch type roof was greater than peach type in air inflated one span greenhouse. The transmittance of air inflated greenhouse was greater than conventional type due to frame ratio and distance between double layers in three span greenhouse. The condensation occurred on conventional type greenhouse was more than air inflated type. It was required to examine for a long time in order to analyze it quantitatively.

• Horticultural Science & Technology
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• v.29 no.5
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• pp.420-432
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• 2011

Population dynamics of greenhouse whitefly, Trialeurodes vaporariorum (Westwood), were modeled and simulated to compare the temperature effects of air and tomato leaf inside greenhouse using DYMEX model simulator (pre-programed module based simulation program developed by CSIRO, Australia). The DYMEX model simulator consisted of temperature dependent development and oviposition modules. The normalized cumulative frequency distributions of the developmental period for immature and oviposition frequency rate and survival rate for adult of greenhouse whitefly were fitted to two-parameter Weibull function. Leaf temperature on reversed side of cherry tomato leafs (Lycopersicon esculentum cv. Koko) was monitored according to three tomato plant positions (top, > 1.6 m above the ground level; middle, 0.9 - 1.2 m; bottom, 0.3 - 0.5 m) using an infrared temperature gun. Air temperature was monitored at same three positions using a Hobo self-contained temperature logger. The leaf temperatures from three plant positions were described as a function of the air temperatures with 3-parameter exponential and sigmoidal models. Data sets of observed air temperature and predicted leaf temperatures were prepared, and incorporated into the DYMEX simulator to compare the effects of air and leaf temperature on population dynamics of greenhouse whitefly. The number of greenhouse whitefly immatures was counted by visual inspection in three tomato plant positions to verify the performance of DYMEX simulation in cherry tomato greenhouse where air and leaf temperatures were monitored. The egg stage of greenhouse whitefly was not counted due to its small size. A significant positive correlation between the observed and the predicted numbers of immature and adults were found when the leaf temperatures were incorporated into DYMEX simulation, but no significant correlation was observed with the air temperatures. This study demonstrated that the population dynamics of greenhouse whitefly was affected greatly by the leaf temperatures, rather than air temperatures, and thus the leaf surface temperature should be considered for management of greenhouse whitefly in cherry tomato grown in greenhouses.

• Journal of The Korean Association For Science Education
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• v.23 no.5
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• pp.592-598
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• 2003

The purpose of this study is to analyze the tenth grade science textbooks as an origin of misconception on greenhouse effect concept and find incorrect descriptions on that concept and then suggest some improved schemes. Some incorrect descriptions, pictures. tables and experiments related to misconceptions on greenhouse effect were found in textbooks. They are considered to contribute to form and reinforce misconceptions on that concept : the most important gas of greenhouse effect, the role of $CO_2$ on the change of greenhouse effect. global warming. energy sources, greenhouse experiments and the physical processes of greenhouse effect. So some improved schemes were suggested

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.137-137
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• 2017

현재 상용화되어 있는 온실 환경제어시스템의 S/W 및 H/W는 서로 호환이 되지 않아 농민들이 원하는 맞춤형 복합 환경 제어시스템을 운영하는데 어려움이 있다. 따라서 본 연구는 다양한 제어알고리즘 및 장비를 적용시킬 수 있는 호환성이 향상된 온실 환경 제어인터페이스 모듈 성능평가를 목표로 한다. 센서 및 제어 인터페이스 모듈 성능평가를 위해 사용된 제어 시스템은 8 bit MCU가 적용된 전용 개발보드를 사용하였고, RS-232 통신 케이블을 사용하여 온실 환경 측정 데이터 값을 PC에서 수신할 수 있도록 하였다. 또한, 창개폐기, 환풍기를 사용하여 온실 내부 온/습도 환경조성을 하였다. 실험은 정오부터 제어장비를 작동시킨 후 1시간 간격으로 총 3시간 동안의 온실 내 온/습도의 변화량을 계측하였다. 3시간 중 1시간동안의 온/습도 값의 변화량을 계측한 결과 평균값은 각각 $33.21^{\circ}C$, 34.94%이었고 표준편차는 각각 $1.44^{\circ}C$, 2.74% 이었다. 제어 알고리즘은 단순한 ON/OFF 방법을 사용 하였고 총 2가지 제어장비를 사용하였으며 모두 정상 작동 하였다. 1시간동안 온실의 온도는 $30^{\circ}C{\sim}35^{\circ}C$사이를 유지하였으며, 습도는 30%~ 40% 사이로 최초 실험 목표였던 온실 내부의 온/습도 범위를 유지하였다. 이번 실험은 ON/OFF 방법의 제어 알고리즘을 사용하였지만 더욱 정밀한 온실 환경제어를 위하여 PID, 퍼지 제어 알고리즘을 추가하여 기상환경에 따른 제어범위를 더욱 세밀화 할 수 있도록 설계한다면 제어장비에 대한 효율성이 향상될 것이라 기대한다.

• Journal of Bio-Environment Control
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• v.20 no.2
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• pp.78-82
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• 2011

Ventilation rates, inside and outside weather data were measured in a arch-shape single-span plastic greenhouse growing tomatoes. On the roof of the experimental greenhouse, round windows which have a diameter of 0.6 m were installed at intervals of 8m. It showed that the number of air changes in this greenhouse were average 0.17 volumes per minute and in the range of 0.02 to 0.32 volumes per minute. These air changes are insufficient to meet the recommended ventilation rate for commercial greenhouses, and it is estimated that interval of 6 m is appropriate for spring or fall season. For summer season, it is necessary to narrow the space or to enlarge the open area of roof windows. Using the heat balance model, the evapotranspiration coefficients of greenhouse tomatoes were estimated from experimental ventilation data, overall heat transfer and solar radiation. It showed that the evapotranspiration coefficients were average 0.62 and in the 0.39 to 0.85 range. We suggest applying 0.6 as the evapotranspiration coefficient in design of ventilation for the single-span tomato greenhouses.

• Journal of Bio-Environment Control
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• v.10 no.1
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• pp.10-14
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• 2001

The cooling effect of a fog cooling system has a close relationship to air flow and relative humidity in the greenhouse. From the VETH chart for cooling design, a cooling efficiency can be improved by means of increasing the air exchange rate and the amount of sprayed water. In the no shading experimental greenhouse by time control, when average air exchange rate was 0.77 times.min$^{-1}$ and spray water amount was 2,009g, inside temperature of the greenhouse was 31$^{\circ}C$ that was almost close to outside temperature and cooling efficiency was 82%. When average air exchange rate was close to temperature of the greenhouse that was no cooling and 70% shading greenhouse environment. When average air exchange rate was 2.59times.min$^{-1}$ , spray water amount was 2,009g and shading rate was 70%, inside relative humidity of the greenhouse was increased was 2,009 g and shading rate was 70%, inside relative humidity of the greenhouse was increased, but temperature was not decreased. When average air exchange rate was 2.33 times.min$^{-1}$ and spray water amount was 2,009g, inside temperature was 31.4 and at that time maximum wind speed at the air inlet of greenhouse was 1.9m.s$^{-1}$ . Since time controller sprayed amount of constant water at a given interval, some of sprayed water remained not to be evaporated, which increased relative humidity and decreased cooling efficiency. Because the shading screen prevented air flow in the greenhouse, it also caused the evaporation efficiency to be decreased. In order to increase cooling efficiency, it was necessary to study on controling by relative humidity and air circulation in the greenhouse.