• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.3
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• pp.119-126
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• 2017

Recently, ground source heat pump systems are being used in buildings for cooling and heating to reduce greenhouse gas and save energy. However, ground source heat pump systems mainly use the vertical closed-loop geothermal system design rather than the open-loop geothermal system design. This is due to a lack of knowledge and few research feasibility studies. In this research, a dynamic thermal analysis numerical simulation based on a standard house model was conducted for an open-loop geothermal system. Based on heating load analysis results, the life cycle costs of a standard house using an open two-well geothermal system were analyzed and compared with a vertical closed-loop geothermal system, and a diesel boiler. As a result, it was found that using an open two-well geothermal system shows economic return on investment after three years.

• Journal of Bio-Environment Control
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• v.21 no.2
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• pp.79-87
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• 2012

This research was conducted to obtain basic data with regard to the heating performance that would be produced by installing an aluminum hot water pipe inside the greenhouse with the goal of reducing the heating energy in greenhouse. The research results are summarized as follows. The degree of difference in relation to the temperature by height within the greenhouse during the entire experiment was significant - within the range of 4.0~$7.0^{\circ}C$. The temperature difference between incoming and outgoing water was about $3.3^{\circ}C$ greater when FCU was activated compared to when it was not activated. Meanwhile, the amount of energy consumed increased about 36.2~40.1%. The amount of pyrexia per hour also increased by 44.6~52.0%. During the experiment period, circulated flux was within the range of 0.48~$0.49L{\cdot}s^{-1}$ while average fluid speed was 1.53~$1.56m{\cdot}s^{-1}$. The average temperature difference between incoming and outgoing water was 6.24~$11.50^{\circ}C$. The amount of heating value by each set temperature within the minimum outdoor temperature range of -14.0~$-0.6^{\circ}C$ was 135,930~307,150 kcal, and the range was within the 9,610~$19,630kcal{\cdot}h^{-1}$ per hour. This demonstrated that about 23~53% heating energy of the maximum heating load could be supplied. Total radiating value and amount of energy consumed were 2,548,306 kcal and 3,075.7 kWh, respectively. When heating takes place using oil, which is a fossil fuel, the total amount of light oil consumed was 281.6 L while the cost was 321,000 won. When the electricity cost for farms is applied, the total cost was about 110,730 won, which is about 33.5% of the cost required compared to oil consumption. The temperature at in the experiment area was about 8.3~$14.6^{\circ}C$ higher compared to that of the control area.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1998.10a
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• pp.5-10
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• 1998

최근 온실에 온수 보일러를 설치하여 실내를 가온하는 시스템이 많이 도입되고 있다. 이들 장치들은 설정된 실내온도를 맞추기 위한 온도 제어장치가 부가되어 있지만, 대부분 ON-OFF제어 시스템을 구성하고 있기 때문에 온도 진폭의 현상이 발생하여 온도 제어 정밀성이 떨어지고 에너지소비도 많다. 이 문제점을 해결하기 위하여는 보일러 온수저장조와 온설 내 방열관 사이에 삼방변을 설치하고 설정온도, 실내온도 및 외기온을 비교하여 삼방변의 위치를 조절하여야 한다. (중략)

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1999.07a
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• pp.326-331
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• 1999

1997년말 현재 우리나라의 시설재배면적은 47,264㏊이며 이 중 85%인 40,000㏊ 정도가 무가온 단동비닐온실이다. 이런 단동온실은 난방을 하지 않고 그림 1과 같이 보온덮개를 사용하는 무가온 재배를 하고 있으며, 온실내에 보온덮개를 덮기 위한 터널을 설치하고 있는데 이 터널의 설치에 사용되는 골조는 강선 또는 FRP재로 길이는 1.8-2.4m이고, 터널폭은 0.9-l.2m 정도로 하고 있다. (중략)

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• v.10 no.2
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• pp.233-236
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• 2005

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2001.04b
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• pp.86-87
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• 2001

자갈축열 태양열온실의 기본원리는 주간에 일사로 데워진 온실내부공기를 자갈축열층사이로 순환시켜 이때 자갈층에 축열된 에너지를 난방에 이용하는 것이므로 축열층 사이로 충분한 공기순환이 이루어져야 한다. 따라서, 자갈축열층내로 순환되는 공기의 풍량이 축열성능과 밀접한 관계가 있으며 효과적인 공기 순환방식을 분석하고자 자갈축열성능실험을 수행하였다. (중략)

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1999.11a
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• pp.104-108
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• 1999

1998년말 현재 우리나라의 시설원예 면적은 48,612ha이고 전체의 90.2%인 43,852ha가 단동비닐온실을 비롯한 관행온실이고, 9.8%인 4,760ha만이 자동화 온실이다. 관행의 단동비닐온실은 태양광에 의존하여 무가온으로 재배하고 있으며, 대부분 2중 하우스로 하거나 내부에 터널을 설치하여 보온덮개를 개폐하는 방식의 보온을 위주로 하여 온실의 온도를 관리한다. (중략)

• Korean Journal of Agricultural Science
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• v.41 no.3
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• pp.251-258
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• 2014

In order to set up the basic environmental control systems which the new concept greenhouses have to equip, greenhouse characteristics, environmental management and control systems in domestic glasshouses and plastic houses were investigated and analyzed comparatively. Survey results on the width, length, eaves height, and the number of spans etc. showed that glasshouses were bigger than plastic houses significantly. New concept greenhouses claim to be plastic houses, but it will be reasonable to follow the specifications of the glasshouse. Specifications to be applied to new concept greenhouses were proposed as follows; hot water heating systems, aluminum screens as the thermal curtain, evaporative cooling systems, roof vents on the ridge, circulation fans, $CO_2$ enrichment, hydroponic systems, and automatic irrigation control systems. Environmental measurement systems for the indoor and outdoor temperature, humidity, light, wind speed and indoor $CO_2$ concentration have to be fully equipped. The automatic control system has to be as a complex environmental control system, not a single item control system. Also, for stable dissemination, domestically producing complete greenhouse control system should be made as soon as possible.

• Journal of Bio-Environment Control
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• v.27 no.3
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• pp.269-275
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• 2018

In order to establish the criterion for analyzing outdoor weather conditions in the greenhouse heating and cooling system design, we analyzed heating and cooling design outdoor temperatures by the annual percentile method and compared with design outdoor temperatures by the existing seasonal percentile method. In the annual percentile method, 0.4%, 1% and 2% of the total 8,760 hours per year are presented as cooling design outdoor temperatures and 99.6% and 99% as heating design outdoor temperatures. When the annual percentile method was adopted, heating design outdoor temperatures increased by 6.7 to 9.6% compared with the seasonal percentile method, and cooling design outdoor temperatures decreased by 0.6 to 1.1%. The maximum heating load in the same greenhouse condition decreased by 3.0 to 3.6% when the annual percentile method was adopted, but the effect on the maximum cooling load was insignificant. Therefore, it is necessary to consider the change of heating design outdoor temperatures to the annual percentile method, but it is not necessary to change the cooling design outdoor temperatures since there is little difference between the two methods.

• Journal of Biosystems Engineering
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• v.20 no.2
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• pp.162-172
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• 1995

The ventilation in greenhouse have been important for such as adjustment of temperature, supplying of the oxygen, prevention of the overhumidity, density adjustment of $CO_2$, discharge of harmfulness gas, etc. However, the general ventilation which had been used the quantitative control method in discharge of a property of air mechanism in greenhouse, and caused mainly in waste of the heating energy and growth obstacle of the vegetable. Therefore, this study was peformed to obtain more scientific ventilation method using by analysis and measurement of the isothermal lines according to opening of window ventilation in greenhouse, and the results are summarized as follows. 1. The ventilating amount was more influenced by rather opening amount of window than the ventilating time. 2. In window ventilation, the temperature in greenhouse was mostly changed within 5 minutes after ventilating not regard to the spot of opening, after about 10 minutes temperature became to equilibrium state under the respective ventilating conditions. 3. In opening of the skylight only, isothermal lines were complicated, therefore, a tall vegetable may be possible to damage by a cold-weather from the lower central port in greenhouse. 4. Isothermal lines were a tendency to simply in opening of a side window that may be more effective ventilation in kinds of the short vegetable. 5. In conditions of internal temperature>setting temperature>external temperature, a skylight can be suitable to open 10~20cm in order to the optimum ventilation in greenhouse. 6. In conditions of internal temperature>external temperature>setting temperature, opening of all the windows or both the side windows that can be suitable in order to obtain the optimum ventilation in greenhouse. 7. An effect of ventilation was the most excellent to open of all the windows or both the side windows, and it were also found orderly excellent to open of the side window and the skylight or the skylight only, to open of the side window only. 8. Temperature was varied as the equation of T=Tc+ (To-Tc)e-at, and the ranges of (a) values were limited within 0.34~0.68. 9. A variations of humidity were similar to that of temperature, s.