• 한국태양에너지학회 논문집
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• 제32권6호
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• pp.60-67
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• 2012

Government Geothermal Cooling-Heating Projects has made efforts to reduce GHG(Greenhouse Gas) emissions and to manage cost of greenhouse farm households. This study evaluated the economic benefits of heating load rate of change by comparing Geothermal Cooling-Heating System with the existing system(greenhouse diesel heating) in the Government Geothermal Cooling-Heating Projects. Economic analysis results shows that, 1) When installing the Cooling-Heating system according to the ratio of 70% heating load in policy standards, the geothermal cooling-heating system has economic efficiency with greenhouse type or scale independent because the investment cost is recovered within 7 years. And It was more economic efficiency the ratio of 50% heating load than70% heating load. 2) When installing the Cooling-Heating system according to the glass greenhouse of the ratio of 90% heating load, pay period of investment cost is recovered within 5 years. Therefore it is necessary to apply flexible heating sharing according to greenhouse type or scale.

• 한국농공학회논문집
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• 제54권3호
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• pp.113-124
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• 2012

Reliable estimation of energy load inside the greenhouse and the selection of cooling and heating facilities are very important preceding factors to save energy as well as initial and maintenance costs of operating a greenhouse. Recently, building energy simulation (BES) technique to simulate a model similar to the actual conditions through a variety of dynamic simulation methods, and predict and analyze the flow of energy is being actively introduced and developed. As a fundamental research to apply the BES technique which is mainly used for analysis of general buildings, to greenhouse, this research designed four types of naturally-ventilated greenhouses using one of commercial programs, TRNSYS, and then compared and analyzed their energy load properties, by applying meteorological data collected from six regions in Korea. When comparing the greenhouse load of each region depending on latitude and topographical characteristics through simulation, Chuncheon had nearly 9~49 % higher heating load per year than other regions, but its annual cooling load was the reverse to it. Except for Jeju, 1-2W type greenhouses in five regions showed about 17 % higher heating load than a widespan type greenhouse, and 1-2W type greenhouses in Chuncheon, Suwon, Cheongju, Daegu, Cheonju and Jeju had 23 %, 20 %, 17 %, 16 %, 18 % and 20 % higher cooling load respectively than a wide span-type one. Glasshouse and vinyl greenhouse showed 8~11 % and 10~12 % differences respectively in heating load, while 2~10 % and 7~10 % differences in cooling load respectively.

• Journal of Biosystems Engineering
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• 제27권6호
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• pp.565-572
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• 2002

In order to control the root-zone temperature of greenhouse crops in the hydroponics at hot and cold season, heat pump system for cooling and heating was built and tested in this work. The system was air-to-water type and vapour compression type. The heating and cooling mode was selected by the four way valve. Capacity of the compressor was 3.75㎾ and heat transfer area of the evaporator and the condenser were 3.05㎡ and 0.6㎡, respectively. According to the performance test, it could supply heat of 42,360 to 64,372kJ/h depending on the water circulation rate of 600 to 1,500ℓ/h, respectively, when indoor air temperature was 10∼20$\^{C}$. COP of heat pump system was 3.0 to 4.0 in the heating mode. But, COP of the cooling mode was 1.3 to 2.1 at indoor temperature of 20∼35$\^{C}$. The feasibility test in the greenhouse the developed heating and cooling system was installed, showed that the heating cost of the developed system was only about 13% of that of the conventional heating system. The heating cost of the developed system was 367won/day(electric consumption 9.7㎾h/day), while that of the conventional system was 2,803won/day(oil consumption 7.7ℓ/day) at the same heating mode.

• 생물환경조절학회지
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• 제32권3호
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• pp.181-189
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• 2023

수소는 다양한 신재생에너지 중 환경친화적인 에너지로 각광받고 있지만 농업에 적용된 사례는 드물다. 본 연구는 수소연료전지 삼중 열병합 시스템을 온실에 적용하여 에너지를 절약하고 온실가스를 줄이고자 한다. 이 시스템은 배출된 열을 회수하면서 수소로부터 난방, 냉각 및 전기를 생산할 수 있다. 수소 연료 전지 삼중 열 병합 시스템을 온실에 적용하기 위해서는 온실의 냉난방 부하 분석이 필요하다. 이를 위해서는 온실의 형태, 냉난방 시스템, 작물 등을 고려해야 한다. 따라서 본 연구에서는 건물 에너지 시뮬레이션(BES)을 활용하여 냉난방 부하를 추정하고자 한다. 전주지역의 토마토를 재배하는 반밀폐형 온실을 대상으로 2012년부터 2021년까지의 기상데이터를 수집하여 분석했다. 온실 설계도를 참고하여 피복재와 골조를 모델화하여 작물 에너지와 토양 에너지 교환을 실시했다. 건물 에너지 시뮬레이션의 유효성을 검증하기 위해 작물의 유무에 의한 분석, 정적 에너지 및 동적 에너지 분석을 실시했다. 또한 월별 최대 냉난방 부하 분석에 의해 평균 최대 난방 용량 449,578kJ·h^-1, 냉방 용량 431,187kJ·h^-1이 산정되었다.

• KIEAE Journal
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• 제16권5호
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• pp.103-109
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• 2016

Purpose: In Korea, to reduce greenhouse gas emissions, energy performance standard of buildings is being reinforced with goals of Passive House until 2017 and Zero Energy House until 2025 in order to reduce emissions from buildings which constitute a quarter of greenhouse gas emissions. In order to achieve the target of Zero Energy House, it is certainly necessary to develop renewable energy that can replace cooling and heating energy occupying a significant amount of building energy consumption after increasing the energy performance firstly. Method: In this study, effects of heat in greenhouse heated by solar heating on indoor heating were analyzed by constructing a greenhouse in front of the Low Energy Building. Result: As a result, indoor temperature was increased by peak average $27.8^{\circ}C$, peak average $6.8^{\circ}C$ was increased from when heat in greenhouse has not been used for heating and indoor surface temperature was increased by average $5.1^{\circ}C$. It shows it can be possible to use heat in greenhouse for heating, if the heating effects can be same as this experimental result because Energy Saving-Type buildings such as Low Energy House or Passive House keep from 18 to $20^{\circ}C$ in winter. Therefore, even if energy supply is cut off by disasters and other reasons, cooling and heating can be possible for some time.

• 한국농공학회논문집
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• 제51권6호
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• pp.45-52
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• 2009

This study was conducted in the process that the basic plan of the formation of the thermal energy complex in the Iwon reclaimed land of Taean was being made. Targeting for the large-sized greenhouse to be made in this area, it examined the cooling and heating load and the amount of ventilation, and also analyzed the economic efficiency of heating. The research results are as per the below: The minimum ambient temperature of this area was measured on January 7, 2001, which was $-18.7^{\circ}C$, and the maximum ambient temperature of this area was measured on July 24, 1994, which was $36.7^{\circ}C$. The maximum heating load was 39,011 MJ/h, but the date when the maximum heating load was not consistent with the date when the minimum temperature was measured. The maximum cooling load was 88,562MJ/h, It was approximately 2.3 times of the maximum heating load, which was measured at 14:00 hours on September 4, 2000. The maximum amount of ventilation heat was 138,639MJ/h. Assuming the rate of solar heat use as 10%, 20%, 50%, and 100%, the total sum of cost-benefit would be ￦-193,450,000, ￦-634,930,000, ￦-3,372,960,000, and ￦-9,850,420,000, respectively 20 years later. The break-even point of the geothermal heat pump would be about 4 years for 10% use, about 3 years for 20% or 50% use, and approximately 6 years for 100% use. It was found that 50% use would be most advantageous. In case two systems are combined, the break-even point will be 10 years, 8 years, and 11 years respectively.

• 한국수소및신에너지학회논문집
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• 제34권6호
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• pp.667-672
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• 2023

This study proposes polymer electrolyte membrane fuel cell (PEMFC) based cogeneration system for greenhouse heating and cooling. The main scope of this study is to examine the proposed cogeneration system's suitability for the 660 m²-class greenhouse. A 25 kW PEMFC system generates electricity for two identical air-cooled heat pumps, each with a nominal heating capacity of 70 kW and a cooling capacity of 65 kW. Heat recovered from the fuel cell supports the heat pump, supplying hot water to the greenhouse. In cooling mode, the adsorption system provides cold water to the greenhouse using recovered heat from the fuel cell. As a result, the cogeneration system satisfies both heating and cooling capability, performing 175 and 145 kW, respectively.

• 생물환경조절학회지
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• 제25권2호
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• pp.123-132
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• 2016

The importance of energy saving technology for managing greenhouse was recently highlighted. For practical use of energy in greenhouse, it is necessary to simulate energy flow precisely and estimate heating/cooling loads of greenhouse. So the main purpose of this study was to develope and to validate greenhouse energy model and to estimate annual/maximum energy loads using Building Energy Simulation (BES). Field experiments were carried out in a multi-span plastic-film greenhouse in Jeju Island ($33.2^{\circ}N$, $126.3^{\circ}E$) for 2 months. To develop energy model of the greenhouse, a set of sensors was used to measure the greenhouse microclimate such as air temperature, humidity, leaf temperature, solar radiation, carbon dioxide concentration and so on. Moreover, characteristic length of plant leaf, leaf area index and diffuse non-interceptance were utilized to calculate sensible and latent heat exchange of plant. The internal temperature of greenhouse was compared to validate the greenhouse energy model. Developed model provided a good estimation for the internal temperature throughout the experiments period (coefficients of determination > 0.85, index of agreement > 0.92). After the model validation, we used last 10 years weather data to calculate energy loads of greenhouse according to growth stage of greenhouse crop. The tendency of heating/cooling loads change was depends on external weather condition and optimal temperature for growing crops at each stage. In addition, maximum heating/cooling loads of reference greenhouse were estimated to 644,014 and $756,456kJ{\cdot}hr^{-1}$, respectively.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2002년도 학술발표회 발표논문집
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• pp.61-64
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• 2002

We constructed climagraphs for 16 regions of Korea by using the average monthly minimum air temperature, maximum air temperature and global radiation. We characterized the outside climate requirements corresponding to the climate requirements of crops in greenhouses. The climagraphs allow to decide the appropriate climate periods for greenhouse cultivation without heating and cooling equipment. These graphs may be used for analyzing climatic characteristic of a given area, selecting the suitable region and greenhouse and making a rational plan for greenhouse cropping in Korea. We found difficulty in deciding the beginning and end of greenhouse heating and cooling period due to insufficient references.

• 생물환경조절학회지
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• 제25권4호
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• pp.308-319
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• 2016

온실의 냉난방시스템 설계 기준에 적용하기 위한 외부기상조건을 설정하기 위하여 난방 설계용 외기온, 난방 degree-hour, 냉방 설계용 건구온도, 습구온도, 일사량을 분석하여 제시하였다. 우리나라 전 지역을 대상으로 현재 기상청에서 제공하는 기후평년값 기준인 1981~2010년까지 30년간의 매 시각 기상자료를 분석에 사용하였다. 표준기상데이터의 이용이 제한적이기 때문에 30년간의 전체 기상자료를 이용하여 설계용 기상조건을 구하고, 전체 자료기간의 평균값을 설계기준으로 제시하였다. TAC 방식으로 위험률 1, 2.5, 5%에 대한 설계용 기상자료를 분석하고, 설계기준에서 추천하고 있는 난방용은 위험률 1%, 냉방용은 위험률 2.5%의 기상조건 분포도를 제시하였다. 지역별, 위험률별 및 설정온도별로 최대난방부하, 기간난방부하 및 최대냉방부하의 변화를 고찰하였다. 제시된 각종 설계용 기상조건은 온실의 냉난방시스템 설계에 직접 이용할 수 있을 뿐만 아니라 냉난방 설비 보강이나 에너지 절감대책의 수립에 활용이 가능할 것으로 판단된다. 한편 기후변화로 인하여 최근 여름철 폭염이나 겨울철 이상고온 현상이 자주 발생하고 있으므로 주기적인 설계용 기상자료의 분석이 필요하고, 최소한 10년 주기로 설계기준을 개정할 필요가 있는 것으로 생각된다. 본 연구에서는 현재 기후평년값 기준인 1981~2010년까지의 기상자료를 분석하였으나 이 기준이 1991~2020년으로 바뀌는 2021년에는 즉시 이 기간의 기상자료를 분석하여 새로운 설계기준으로 제공해야 할 것으로 판단된다.