• Title/Summary/Keyword: Greenhouse horticulture

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Heat Transfer Characteristics of Coil Tube Heat Exchanger for Hot Water Heating of Greenhouse Thermal Tunnel (보온터널 난방을 위한 온수난방용 코일튜브 열교환기의 열전달 특성)

  • Ryou, Y.S.;Kang, K.C.;Kim, Y.J.;Paek, Y.;Kang, Y.G.;Lee, H.M.
    • Journal of Biosystems Engineering
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    • v.31 no.5 s.118
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    • pp.430-435
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    • 2006
  • Greenhouse horticulture in South Korea covered about 52,000 ha in 2005. Greenhouse area of about 12,000 ha has been heated during winter season with heating cost of $20{\sim}40%$ of total Production cost. Farmers engaged in greenhouse horticulture were changed into aged people. Therefore the laborsaving of working process and the saving of greenhouse heating cost should be accomplished simultaneously to increase income of greenhouse horticulture. The best method for saving of greenhouse heating cost is to install thermal tunnels into greenhouse. Then hot air heaters using fossil fuel should be changed into hot water heaters. In other words air heating using forced convection should be changed into natural convection system. In this research coil tube made of flexible PE pipe was designed as hot water heat exchanger and its heat exchanging characteristics were analyzed. This new heat exchanger has been adopted as a natural convection system for hot water heating of greenhouse horticulture.

Finite element modeling for structure-soil interaction analysis of plastic greenhouse foundation (온실기초의 구조물-지반 상호작용 해석을 위한 유한요소 모델링)

  • Ryu, Hee-Ryong;Cho, Myeong-Whan;Yu, In-Ho;Moon, Doo-Gyung
    • Korean Journal of Agricultural Science
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    • v.41 no.4
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    • pp.455-460
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    • 2014
  • In this study, structural behavior of plastic greenhouse foundation was investigated using rational finite element modeling for structures which have different material properties each other. Because the concrete foundation of plastic greenhouse and soil which surround and support the concrete foundation have very different material property, the boundary between two structures were modeled by a interface element. The interface element was able to represent sliding, separation, uplift and re-bonding of the boundary between concrete foundation and soil. The results of static and dynamic analysis showed that horizontal and vertical displacement of concrete foundation displayed a decreasing tendency with increasing depth of foundation. The second frequency from modal analysis of structure including foundation and soil was estimate to closely related with wind load.

A field survey on roof ventilation system of single-span plastic greenhouse in cucurbitaceae vegetable cultivation (박과작물 재배 단동 비닐하우스의 천장 환기시스템 설치 실태조사)

  • Yeo, Kyung-Hwan;Yu, In-Ho;Rhee, Han-Cheol;Cheong, Jae-Woan;Choi, Gyeong Lee
    • Korean Journal of Agricultural Science
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    • v.40 no.4
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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.

Shoot Growth Characteristics and Climatic Factors in Greenhouse Cultivation of Mulberry (뽕나무의 온실재배에서 신초 생육 특성과 기상 요인)

  • Kim, Ho-Cheol;Kwon, Tae-Oh;Bae, Jong-Hyang;Kim, Tae-Choon
    • Journal of Bio-Environment Control
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    • v.21 no.1
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    • pp.74-78
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    • 2012
  • This research was carried out to investigate the shoot growth characteristics and climatic factors for early harvest and stable yield by greenhouse on mulberry ($Morus$ $alba$) in Buan-gun, Jeollabuk-do. Budbreak and coloring date of mulberry in greenhouse were earlier 18~19 days than those in field, and from bud-break to coloring was 39 days in both cultivation types. Shoot length and fruit number per shoot of mulberry in greenhouse were not significantly different with those of field, but number of node was significantly little than that of field. For 39 days in greenhouse, weekly cumulative radiation were 0.3~0.8 times. But weekly cumulative temperature was not different with that of field. And relative humidity as range of 53.0~94.5% in greenhouse was higher than that of field. Therefore, mulberry is suitable to greenhouse cultivation for early harvest and stable yield.

Development of CFD model for analyzing the air flow and temperature distribution in greenhouse with air-circulation fans (유동팬이 설치된 온실 내 기류 및 기온분포 해석을 위한 CFD 모델 개발)

  • Yu, In-Ho;Yun, Nam-Kyu;Cho, Myeong-Whan;Ryu, Hee-Ryong;Moon, Doo-Gyung
    • Korean Journal of Agricultural Science
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    • v.41 no.4
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    • pp.461-472
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    • 2014
  • This study was conducted to build the CFD simulation model which can quantify the distribution of the meteorological factors in air-heated greenhouse for chrysanthemum according to the location and capacity of air-circulation fan. The CFD model was also verified by experiment. It was judged that SST model was the most appropriate turbulence model which can properly describe the airflow by the air-circulation fan. According to the simulation results, the differences between the measured and predicted temperatures from 18 points at each height in the greenhouse were $0.2{\sim}0.4^{\circ}C$ in average. This showed a good agreement between the predicted data and the measured ones. The developed CFD model can be a useful tool to evaluate and design the air-circulation systems in the greenhouse with various configurations.

A Study on the Landscape Preference Analysis of Facility Horticulture Complex in Rural Area - Focus on Korea, Netherlands, Japan - (농촌지역 시설원예단지 경관선호도 분석 연구 - 한국, 네덜란드, 일본을 대상으로 -)

  • Son, Jinkwan;Kong, Minjae;Shin, Minji;Shin, Jihoon;Kang, Donghyeon;Yun, Sungwook;Lee, Siyoung
    • Journal of Korean Society of Rural Planning
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    • v.23 no.4
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    • pp.27-38
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    • 2017
  • Humans are provided with a wide range of public benefits from ecosystems and agricultural ecosystems. But the establishment of the horticulture complex is a space that hampers the public ecosystem. Therefore, we have evaluated the creating landscape function of the horticulture complex and found improvement. A total of 20 landscape slides were used for the study. Korea-paddy field, Korea-vinyl greenhouse, Korea-glass greenhouse, Japan-vinyl greenhouse and Netherlands-glass greenhouse were selected as 4 slides. The evaluation used the AHP method and 10 adjectives Likert which compares 20 landscape slides. Four Korea-paddy fields were rated highly positive images. All 10 adjectives can be selected as representative images of production scenes. In most adjectives, four scenes of KVG1, KVG2, KVG3 and KVG4, which are the Korea-greenhouse scenes, were evaluated as negative images. Netherlands and Korea-glass greenhouse scenes and Japan-vinyl greenhouse scenes were generally positive images. In conclusion, it is confirmed that glass greenhouse scenery is higher than vinyl greenhouse scenery. And Japan and Netherlands scenery are higher and better than Korea. Therefore, JVG1 in Japan and NGG3 in the Netherlands were proposed to be set as landscape improvement targets.

Screening of Deoxynivalenol Producing Fungi from Greenhouse Horticulture by Enzyme Amplification System Immunoassay (Enzyme Amplification System Immunoassay에 의한 시설원예산물의 Deoxynivalenol 생성곰팡이의 검색)

  • Park, Mi-Ja;Park, Jung-Hyun;Chung, Duck-Hwa
    • Korean Journal of Food Science and Technology
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    • v.32 no.2
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    • pp.439-443
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    • 2000
  • In order to evaluate the safety of greenhouse horticulture products in Korea, we carried out this work by screening of Fusarium species, which produce deoxynivalenol (DON) from greenhouse horticulture in Western Gyeongnam and Northern Gyeongbuk, Korea. For this study, high sensitive enzyme-linked immunosorbent assay, ALP/NADP method, was applied to detection of DON by enzyme amplification system. From 192 samples of greenhouse horticulture soil and its products, 103 isolates of Fusarium species were obtained. The isolates were cultured at 28C for 15 days and the cultured mediums were extracted by ethyl acetate. The production of DON was verified by thin layer chromatography (TLC). As the results of TLC, 8 strains were identified as DON producing strain. We screened potential producers of DON by ALP/NADP. The levels of DON production were shown from 0.007 to 1.21 g/ml of YES medium. The maximum DON producing strain No. 32-D-3 was isolated from soil in Namhae, Korea. In conclusion, the above results indicate that DON producing fungi contaminated greenhouse horticulture products in Korea. Therefore, further studies are required to accumulate more detailed data about the contamination of DON in various cereals.

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Development of Multi-span Plastic Greenhouse for Tomato Cultivation (토마토 재배용 연동 플라스틱 온실 개발)

  • Yu, In Ho;Lee, Eung Ho;Cho, Myeong Whan;Ryu, Hee Ryong;Kim, Young Chul
    • Journal of Bio-Environment Control
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    • v.21 no.4
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    • pp.428-436
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    • 2012
  • This study aimed to develop the multi-span plastic greenhouse which is suitable for tomato cultivation and is safe against climatic disasters such as typhoon or heavy snow. The width and heights of eaves and ridge of newly developed tomato greenhouse are 7, 4.5 and 6.5 m, respectively. The width is the same but the eaves and ridge heights are 1.8 and 2 m higher than conventional 1-2 W greenhouses, respectively. Cross beam has been designed as a truss structure so it can sustain loads of tomato and equipment. Tomato greenhouse has been designed according to climatic disaster preventing design standard maintaining the high height. In other words, the material dimensions and interval of materials including column and rafter have been set to stand against $40m{\cdot}s^{-1}$ of wind and 40 cm of snow. Tomato greenhouse has been equipped with rack-pinion type roof vents which have been used in glass greenhouse in order to prevent excessive rise in air temperature. This vent type is different from that of 1-2 W type greenhouse which is made by rolling up and down the vinyl at upper part of column. Roof vents are installed at ridge, and thus external air inflow and natural ventilation are maximized. As the height increases, heating cost increase as well and, therefore, tomato greenhouse has been equipped with multi-layered thermal curtain, of which thermo-keeping is excellent, to prevent heat from escaping.