• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2005.05a
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• pp.148-152
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• 2005

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2005.10a
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• pp.89-94
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• 2005

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2004.11a
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• pp.15-20
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• 2004

• Journal of the Korean Solar Energy Society
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• v.35 no.5
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• pp.49-56
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• 2015

In this study a hybrid heating system based on geothermal source and solar heat was developed in order to save energy for greenhouse heating and its field performance was evaluated. Developed system are composed of following parts: water tank, heat exchanger, heat pump, fan coil unit and heat storage unit. The working performance test was carried out in a greenhouse cultivating oriental orchids being managed by $23^{\circ}C$. Field performance test results showed that average heating coefficient of performance ($COP_h$) was 3.4 for the period from mid-January to mid-March 2013. Heating coefficient of performance ($COP_h$) of developed hybrid heat pump system was more sensitive to water tank temperature than outside air temperature. This study showed that developed hybrid heat pump system has a potential to save the heating costs up to 91% compared to conventional agricultural oil heaters.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2007.05a
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• pp.173-177
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• 2007

• Journal of Biosystems Engineering
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• v.41 no.4
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• pp.328-336
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• 2016

Purpose: The heat culture areas of greenhouses have been continuously increasing. In the face of international oil price fluctuations, development of energy saving technologies is becoming essential. To save energy, auxiliary heat source and thermal insulation technologies are being developed, but they lack cost-efficiency. The present study was conducted to save energy by developing a conceptually new semi-basement type greenhouse. Methods: A semi-basement type greenhouse, was designed and constructed in the form of a three quarter greenhouse as a basic structure, which is an advantageous structure to inflow sunlight. To evaluate the performance of the developed greenhouse, a similar structured general greenhouse was installed as a control plot, and heating tests were conducted under the same crop growth conditions. Results: Although shadows appeared during the winter in the semi-basement type greenhouse due to the underground drop, the results of crop growth tests indicated that there were no differences in crop growth and development between the semi-basement type greenhouse and the control greenhouse, indicating that the shadows did not affect the crop up to the height of the crop growing point. The amount of fuel used for heating from January to March was almost the same between the two greenhouses for tests. The heating load coefficients of the experimental greenhouses were calculated as $3.1kcal/m^2{\cdot}^{\circ}C{\cdot}h$ for the semi-basement type greenhouse and $2.9kcal/m^2{\cdot}^{\circ}C{\cdot}h$ for the control greenhouse. Since the value is lower than the double layer PE (polyethylene) film greenhouse value of $3.5kcal/m^2{\cdot}^{\circ}C{\cdot}h$ from a previous study, Tthe semi-basement type greenhouse seemed to have energy saving effects. Conclusions: The semi-basement type greenhouse could be operated with the same fuel consumption as general greenhouses, even though its underground portion resulted in a larger volume, indicating positive effects on energy saving and space utilization. It was identified that the heat losses could be reduced by installing a thermal curtain of multi-layered materials for heat insulation inside the greenhouse for the cultivation of horticultural products by installing thermal curtain of multi-layered materials for heat insulation inside the greenhouse, it was identified that the heat losses could be reduced.

• Korean Journal of Agricultural Science
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• v.41 no.4
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• pp.473-480
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• 2014

Upon setting up a dedicated plastic greenhouse for tomato cultivation developed by the Rural Development Administration on the Gyehwa reclaimed land, this study was aimed at analyzing the problems can be occurred in the installation of plastic greenhouse on reclaimed lands as well as finding out solutions for improvement. A relatively cheaper wooden pile was used in the installation in order to supplement the soft ground conditions. Based on the results of ground investigation of the installation site, both the allowable bearing capacity and pulling resistance of the wooden pile with a diameter of 150 mm and a length of 10 m were computed and came out to be 30.645 kN. It was determined that the values were enough to withstand the maximum compressive force (17.206 kN) and the pullout force (20.435 kN) that are generally applied to the greenhouse footing. There are three problems aroused in the process of greenhouse installation, and the corresponding countermeasures are as follow. First, due to the slightly bent shape of the wooden pile, there were phenomenon such as deviation, torsion, and fracture when driving the pile. This could be prevented by the use of the backhoe (0.2) rotating tongs, which are holding the pile, to drive the pile while pushing to the direction of the driving and fixing it until 5 m below ground and applying a soft vibrating pressure until the first 2 m. Second, there exists a concrete independent footing between the column of the greenhouse and the wooden pile driven to the underground water level. Since it is difficult to accurately drive the pile on this independent footing, the problem of footing baseplate used to fix the column being off the independent footing was occurred. In order to handle with this matter, the diameter of the independent footing was changed from 200 mm to 300 mm. Last, after films were covered in the condition that the reinforcing frame and bracing are not installed, there was a phenomenon of columns being pushed away by the strong wind to the maximum of $11m{\cdot}s^{-1}$. It is encouraged to avoid constructions in winter, and the film covering jobs always to be done after the frame construction is completely over. The height of the independent footing was measured for 9 months after the completion of the greenhouse installation, and it was found to be within the margin of error meaning that there was no subsidence. The extent to the framework distortion and the value of inclinometers as well showed not much alteration. In other words, the wooden pile was designed to have a sufficient bearing capacity.

• Journal of Bio-Environment Control
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• v.13 no.4
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• pp.251-257
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• 2004

This experiment was carried out to investigate the effects of different covering materials and methods on heat insulation of a plastic greenhouse, growth and yield of tomato. Night air and soil temperatures in a double-layer greenhouse with external multifold thermal cover (MTC; eight-ounce cassimere+four-fold polyform+double-fold non-woven fabric+single-fold polypropylene covering were about $1^{\circ}C$ lower than in that with internal MTC covering, but about $3^{\circ}C$ higher than in that with an EVA film screen. Tomato yield in the external MTC covering increased by $2\%\;and\;19\%$ as compared to that in the internal MTC covering and the non-covering of MTC, respectively, due to its high light transmission and insulation effect. Night air temperatures in a double-layer greenhouse with external MTC covering and with thermal screen (polyester plus aluminium) were $2.2^{\circ}C\;and\;4.5^{\circ}C$ higher than those in a double-layer greenhouse with an external MTC covering and in a double-layer greenhouse equipped an EVA film screen, respectively. Tomato yield in the treatment with external MTC covering and a thermal screen was $18\%\;and\;37\%$ greater than that in the external MTC covering and in an EVA film screen, respectively. Results indicate that tomato could be grown without heating or with minimal heating in a double-layer greenhouse covered with MTC and a thermal screen during the winter season in sourthern regions of Korea.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2005.05a
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• pp.214-217
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• 2005

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2006.05a
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• pp.91-97
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• 2006